To see the other types of publications on this topic, follow the link: Magmax.
Journal articles on the topic 'Magmax'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Magmax.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Flannery, John, Rebecca Moore, Laura Marsella, Katie Harris, Martin Ashby, Paulina Rajko-Nenow, Helen Roberts, Simon Gubbins, and Carrie Batten. "Towards a Sampling Rationale for African Swine Fever Virus Detection in Pork Products." Foods 9, no. 9 (August 20, 2020): 1148. http://dx.doi.org/10.3390/foods9091148.
Full textAbstract:
African swine fever (ASF) is a highly lethal disease of pigs caused by the ASF virus (ASFV), which presents a serious threat to global food security. The movement of contaminated pork products has previously been postulated as contributing to the introduction of ASF into new areas. To evaluate the performance of ASFV detection systems in multi-component pork products, we spiked sausage meat with four different ASFV-containing materials (ASFV cell culture, pork loin, meat juice and bone marrow). DNA was extracted using two manual systems (MagMAX CORE, Qiagen) and one automated (MagMAX CORE) one, and three qPCR assays (VetMAX, King, UPL) were used. The performance of the DNA extraction systems was as follows; automated MagMAX > manual MagMAX > manual Qiagen. The commercial VetMAX qPCR assay yielded significantly lower CT values (p < 0.001), showing greater sensitivity than the World Organization for Animal Health (OIE)-prescribed assays (King, UPL). Detection probability was the highest for matrices contaminated with bone marrow compared with pork loin or meat juice. An estimated minimum sample size of one 1-g sample is sufficient to detect ASFV in a homogenous pork product if bone marrow from infected pigs comprises 1 part in 10,000. We demonstrated that existing ASFV detection systems are appropriate for use in a food-testing capacity, which can provide an additional control measure for ASF.
2
Fang, Xingwang, Roy C. Willis, Angela Burrell, Kurt Evans, Quoc Hoang, Weiwei Xu, and Mangkey Bounpheng. "Automation of Nucleic Acid Isolation on KingFisher Magnetic Particle Processors." JALA: Journal of the Association for Laboratory Automation 12, no. 4 (August 2007): 195–201. http://dx.doi.org/10.1016/j.jala.2007.05.001.
Full textAbstract:
We describe automated nucleic acid (NA) isolation from diverse sample types using MagMAX kits (Ambion, Inc.) on KingFisher Magnetic Particle Processors (Thermo Scientific). The MagMAX-96 Blood RNA Isolation Kit is designed for total RNA isolation from whole blood from several species, without white blood cell fractionation, in about 45 min (including genomic DNA removal). The MagMAX-96 Total RNA Isolation Kit is designed for total RNA isolation from up to 2 × 10 6 cultured cells and up to 10-mg tissue. The isolated total RNA is highly intact and pure, ready to use in downstream applications such as microarray analysis or real-time reverse transcription (RT)-PCR for gene expression profiling or pathogen detection. The MagMAX-96 Viral RNA Isolation Kit is designed for viral RNA and DNA isolation from cell free or nearly cell-free samples such as swabs, serum, and plasma; it takes about 15 min. Total NA of high quality and purity is recovered at >75% efficiency, providing high sensitivity for pathogen detection by real-time RT-PCR. Unlike automated liquid handling systems that move reagents into and out of a single well of a multiwell plate to perform the different steps of an RNA isolation procedure, the KingFisher Magnetic Particle Processors use permanent magnetic rods to collect magnetic beads from solution and release them into another well containing reagent for the subsequent step of the procedure. The effectiveness of bead collection and transfer lead to superior washing and elution efficiency, as well as rapid processing. It is a very effective strategy for automation of magnetic-bead-based NA isolation kits. (JALA 2007; 12:195–201)
3
Soldatova, Kristina I., Oleg Ivanovich Kit, Roman E. Tolmakh, Liubov Yu Vladimirova, and Denis S. Kutilin. "Cancer-testis gene-expression features in various tumors." Journal of Clinical Oncology 37, no. 15_suppl (May 20, 2019): e14260-e14260. http://dx.doi.org/10.1200/jco.2019.37.15_suppl.e14260.
Full textAbstract:
e14260 Background: Cancer-testis antigens (CTA) can be an effective target for immunotherapy. Immunotherapeutic approaches targeting CTA in breast cancer (BC), endometrial cancer (EC), ovarian cancer (OC), and colon cancer (CRC) are in the incipient stages of development. The purpose of our study was screening of CTA specific for BC, EC, OC and CRC, based on an analysis of transcriptional profiles of CT-genes. Methods: Tumor and intact tissues of the breast, uterus, ovaries and colon were studied in 35, 30, 20 and 60 patients, respectively. RNAs were isolated using the method described by Chomczynski and Sacchi (2006). The REVERTA-L reagent kit was used for the cDNA synthesis. Relative expression of 16 genes ( MAGEA1, MAGEA2, MAGEA3, MAGEA4, MAGEB1, MAGEB2, GAGE1, GAGE3, GAGE4, MAGEC1, BAGE, XAGE3, NYESO1, SSX2, SCP1, PRAME1) was determined by Real-Time qPCR (with GAPDH and GUSB as reference genes). Statistical analysis was performed using the Mann-Whitney test. Results: BC patients showed significantly (p < 0.005) increased expression of MAGEA3, MAGEA4 and GAGE3 in tumor tissues compared to normal ones; EC patients - significantly (p < 0.05) increased expression of MAGEA1, MAGEA2, MAGEA4, MAGEB2, GAGE3, NY-ESO1, SCP1 and PRAME1 in tumor tissues compared to normal ones; OC patients - significantly (p < 0.05) increased expression of MAGEB1, MAGEB2, GAGE1, NY-ESO1 and decreased expression of MAGEA3, MAGEA4, GAGE3, GAGE4, XAGE3, SSX2, SCP1 and PRAME1; CRC patients - significantly (p < 0.05) increased expression of SSX2 and PRAME1, together with decreased BAGE expression, in tumors compared to normal tissues. Conclusions: Analysis of the transcriptional activity of CT-genes revealed the most common diagnostic markers and immunotherapeutic targets for every malignancy: in BC - MAGEA3, MAGEA4 and GAGE3, in EC - MAGEA1, MAGEA2, MAGEA4, MAGEB2, GAGE3, NY-ESO1, SYCP1 and PRAME1, in OC - MAGEB1, MAGEB2, GAGE1 and NY-ESO, in CRC - SSX2 and PRAME1.
4
Sevilla, Iker A., Joseba M. Garrido, Elena Molina, María V. Geijo, Natalia Elguezabal, Patricia Vázquez, and Ramón A. Juste. "Development and Evaluation of a Novel Multicopy-Element-Targeting Triplex PCR for Detection of Mycobacterium avium subsp. paratuberculosis in Feces." Applied and Environmental Microbiology 80, no. 12 (April 11, 2014): 3757–68. http://dx.doi.org/10.1128/aem.01026-14.
Full textAbstract:
ABSTRACTThe enteropathy called paratuberculosis (PTB), which mainly affects ruminants and has a worldwide distribution, is caused byMycobacterium aviumsubsp.paratuberculosis. This disease significantly reduces the cost-effectiveness of ruminant farms, and therefore, reliable and rapid detection methods are needed to control the spread of the bacterium in livestock and in the environment. The aim of this study was to identify a specific and sensitive combination of DNA extraction and amplification to detectM. aviumsubsp.paratuberculosisin feces. Negative bovine fecal samples were inoculated with increasing concentrations of two different bacterial strains (field and reference) to compare the performance of four extraction and five amplification protocols. The best results were obtained using the JohnePrep and MagMax extraction kits combined with an in-house triplex real-time PCR designed to detect IS900, ISMap02(an insertion sequence ofM. aviumsubsp.paratuberculosispresent in 6 copies per genome), and an internal amplification control DNA simultaneously. These combinations detected 10M. aviumsubsp.paratuberculosiscells/g of spiked feces. The triplex PCR detected 1 fg of genomic DNA extracted from the reference strain K10. The performance of the robotized version of the MagMax extraction kit combined with the IS900and ISMap02PCR was further evaluated using 615 archival fecal samples from the first sampling of nine Friesian cattle herds included in a PTB control program and followed up for at least 4 years. The analysis of the results obtained in this survey demonstrated that the diagnostic method was highly specific and sensitive for the detection ofM. aviumsubsp.paratuberculosisin fecal samples from cattle and a very valuable tool to be used in PTB control programs.
5
Ha, Trang, and Valentina Harizanov. "Orders on magmas and computability theory." Journal of Knot Theory and Its Ramifications 27, no. 07 (June 2018): 1841001. http://dx.doi.org/10.1142/s0218216518410018.
Full textAbstract:
We investigate algebraic and computability-theoretic properties of orderable magmas. A magma is an algebraic structure with a single binary operation. A right order on a magma is a linear ordering of its domain, which is right-invariant with respect to the magma operation. We use tools of computability theory to investigate Turing complexity of orders on computable orderable magmas. A magma is computable if it is finite, or if its domain can be identified with the set of natural numbers and the magma operation is computable. Interesting orderable magmas that are not even associative come from knot theory.
6
Andrade, Valéria C. C., André L. Vettore, Manuella S. S. Almeida, José S. R. Oliveira, Maria de Lourdes L. F. Chauffaille, Mihoko Yamamoto, Adagmar Andriolo, et al. "Prognostic Impact of Cancer Testis Antigens Expression in Advanced Stage Multiple Myeloma Patients." Blood 110, no. 11 (November 16, 2007): 4733. http://dx.doi.org/10.1182/blood.v110.11.4733.4733.
Full textAbstract:
Abstract Background: Cancer testis antigens have become the most extensively studied antigen group in the field of tumor immunology. Aims: This study aims to analyze global expression of 14 CT (cancer/testis) antigens in MM to identify possible prognostic markers and therapeutic targets. Patients and Methods: The expression of MAGEA1, MAGEA2, MAGEA3/6, MAGEA4, MAGEA10, MAGEA12, BAGE1, MAGEC1/CT7, GAGE family, LAGE-1, PRAME, NY-ESO-1, SPA17 and SSX1 was studied by RT-PCR in: 15 normal tissues, one pool of 10 normal bone marrow samples, three normal tonsils and bone marrow aspirates from six normal donors, three monoclonal gammophaties of undetermined significance (MGUS), five solitary plasmacytomas, 39 MM samples (95% advanced stage) and MM cell line U266. CodeLink Human UniSet I Bioarrays 10,000 genes was used for arrays analyses. Results: SPA17 was positive in all normal tissues and was excluded for further analyses. MAGEC1/CT7 was positive in bone marrow aspirates from one MGUS and in one plasmacytoma. U266 cell line was positive for all CT antigens, except SSX1. The frequencies of CT antigens expression in MM patients were: MAGEC1/CT7 = 30/39 (77%); LAGE-1 = 19/39 (49%); MAGEA3/6 = 16/39 (41%); MAGEA2 = 14/39 (36%); GAGE family = 13/39 (33%); NY-ESO-1 = 13/39 (33%); BAGE-1 = 12/39 (28%); MAGEA1 = 10/39 (26%); PRAME = 9/39 (23%); SSX-1 = 10/39 (26%); MAGEA12 = 8/39 (20.5%); MAGEA4 and MAGEA10 = 0%. Cox’s regression model showed that GAGE family positivity and number of positive CT antigens > 6 were independent prognostic factors when all patients were analyzed. However, MAGEC1/CT7 expression was the only independent prognostic factor when non-transplanted patients where analyzed. Three samples predominantly positive (> 6) and three samples predominantly negative (0 or 1) for the 13 analyzed CT antigens were submitted to microarrays analyses. 147 genes were overexpressed in predominantly positive CT antigens samples. Conclusions: Based on our findings, MAGEC1/CT7, MAGEA3/6 and LAGE-1 seem good candidates for immunotherapy, since together they are overexpressed in 85% of our MM cases. Besides, GAGE family expression, number of CT antigens > 6 and MAGEC1/CT7 seem to have impact on MM prognosis. Also, the results of arrays analyses corroborate the hypothesis that MM can be separate in two groups: predominantly positive and predominantly negative for CT antigens, meaning that these antigens may have important role for MM biology.
7
Wiebe, R. A. "Mafic-silicic layered intrusions: the role of basaltic injections on magmatic processes and the evolution of silicic magma chambers." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 87, no. 1-2 (1996): 233–42. http://dx.doi.org/10.1017/s0263593300006647.
Full textAbstract:
ABSTRACT:Plutonic complexes with interlayered mafic and silicic rocks commonly contain layers (1–50 m thick) with a chilled gabbroic base that grades upwards to dioritic or silicic cumulates. Each chilled base records the infusion of new basaltic magma into the chamber. Some layers preserve a record of double-diffusive convection with hotter, denser mafic magma beneath silicic magma. Processes of hybridisation include mechanical mixing of crystals and selective exchange of H2O, alkalis and isotopes. These effects are convected away from the boundary into the interiors of both magmas. Fractional crystallisation aad replenishment of the mafic magma can also generate intermediate magma layers highly enriched in incompatible elements.Basaltic infusions into silicic magma chambers can significantly affect the thermal and chemical character of resident granitic magmas in shallow level chambers. In one Maine pluton, they converted resident I-type granitic magma into A-type granite and, in another, they produced a low-K (trondhjemitic) magma layer beneath normal granitic magma. If comparable interactions occur at deeper crustal levels, selective thermal, chemical and isotopic exchange should probably be even more effective. Because the mafic magmas crystallise first and relatively rapidly, silicic magmas that rise away from deep composite chambers may show little direct evidence (e.g. enclaves) of their prior involvement with mafic magma.
8
Thirumalapura, Nagaraja R., Willard Feria, Eric Hue, Corey Zellers, and Deepanker Tewari. "Evaluation of a high-throughput nucleic acid extraction method for the detection of Mycobacterium avium subsp. paratuberculosis in bovine fecal samples by PCR." Journal of Veterinary Diagnostic Investigation 33, no. 2 (February 1, 2021): 375–78. http://dx.doi.org/10.1177/1040638721991118.
Full textAbstract:
Johne’s disease (paratuberculosis) is an economically important disease of cattle worldwide. The disease is caused by Mycobacterium avium subsp. paratuberculosis (MAP), a fastidious gram-positive bacterium. PCR is increasingly used in diagnostic laboratories for the detection of MAP in fecal samples given the rapid test turnaround time and sensitivity and specificity comparable to fecal culture. However, efficient extraction of DNA for sensitive detection of MAP by PCR is affected by the complex lipid-rich cell wall of MAP and the presence of PCR inhibitors in feces. We evaluated a high-throughput nucleic acid extraction method (MagMAX core nucleic acid purification kit with mechanical lysis module) in conjunction with an hspX gene PCR for the detection of MAP from bovine fecal samples, which resulted in correct identification of all negative (13 of 13) and positive (35 of 35) proficiency test samples obtained from the National Veterinary Services Laboratories. In addition, all 6 negative and 50 of 51 positive diagnostic specimens tested were categorized correctly.
9
Poli, G., S. Tommasini, and A. N. Halliday. "Trace element and isotopic exchange during acid-basic magma interaction processes." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 87, no. 1-2 (1996): 225–32. http://dx.doi.org/10.1017/s0263593300006635.
Full textAbstract:
ABSTRACT:Interaction processes between acid and basic magmas are widespread in the Sardinia–Corsica Batholith. The resulting hybrid magmas are extremely variable and can be broadly divided into: (i) microgranular mafic enclaves with geochemical characteristics of both magmatic liquids and cumulates; (ii) basic gabbroic complexes with internal parts mainly formed by cumulates and with interaction zones developing only in the marginal parts; and (iii) basic septa with the form of discrete, lenticular-like bodies often mechanically fragmented in the host rock. Different styles of interaction, ranging from mixing to mingling, have been related to variations in several physicochemical parameterś, such as: (i) the initial contrast in chemical composition, temperature and viscosity; (ii) the relative mass fractions and the physical state of interacting magmas; and (iii) the static versus dynamic environment of interaction.A model is presented for the origin and history of interaction processes between basic and acid magmas based on the geochemical characteristics of hybrid magmas. Physico-chemical processes responsible for the formation of hybrid magmas can be attributed to: (i) fractional crystallisation of basic magma and contamination by acid magma; (ii) loss of the liquid phase from the evolving basic magma by filter pressing processes; (iii) mechanical mixing between basic and acid magmas; and (iv) liquid state isotopic diffusion during the attainment of thermal equilibrium.
10
Heincz, Adrián, Elemér Pál-Molnár, Balázs Kiss, Anikó Bataki, Enikő Eszter Almási, and Luca Kiri. "Nyílt rendszerű magmás folyamatok: magmakeveredés, kristálycsere és kumulátum-recirkuláció nyomai a Ditrói alkáli masszívumban (Orotva, Románia)." Földtani Közlöny 148, no. 2 (June 10, 2018): 125–42. http://dx.doi.org/10.23928/foldt.kozl.2018.148.2.125.
Full textAbstract:
A Tarniţa Komplexum a Keleti-Kárpátokban (Románia) felszínre bukkanó Ditrói alkáli masszívum északi területének jellemző ultramafikus és mafikus kőzetegyüttese. A komplexum Ny-i részén, az Orotva-patak és a Felső-Pietrăriei-patak összefolyásánál található mélységi magmás kőzettestben kialakított mesterséges feltárás egyedülálló betekintést enged az egykori magmatározóban zajlott, több magma között lejátszódott keveredési és elegyedési folya matokba, illetve az új magmabenyomulások során feltépett, korábban kikristályosodott magmás kőzetfragmen tumok bekeveredési folya mataiba. A feltárásban látható befogadó kőzetben (szürke, közép- és durvaszemcsés, irányított szövetű diorit) négy különböző keveredési kőzetzárvány (mafikus kőzetzárvány; földpátszemes kőzetzárvány; porfíros (földpátaggregátumos), mafikus kőzetzárvány és ultramafikus kőzetzárvány) és egy eltérő eredetű felzikus kőzetzárvány típus figyelhető meg. A keveredési kőzetzárványok modális összetételük alapján mezokrata és melanokrata dioritok, valamint piroxénhorn blenditek, a felzikus kőzetzárványok pedig hololeukokrata dioritok. A különböző magmák közötti keveredés (mingling) legfontosabb bélyege az egymással — és a befogadó kőzet ásványainak orientált elhelyezkedésével — párhuzamos, megnyúlt, finomszemcsés, lencse alakú kőzetzárványok meg jele nése. A szögletes felzikus xenolitok és ultramafikus kőzetzárványok korábbi kumulátumok recirkulációját felté telezik, amelyek a benyomuló magmával kerültek a magmatározóba. A keveredési kőzetzárványok mafikus pereme és a közelükben megfigyelhető „slírek” további fontos jellemzői a legalább két magma keveredése során kialakuló szerke ze teknek. A magmaelegyedés gyakori velejárója a kristálycsere (crystal transfer). A vizsgált ásványok számos esetben mutatnak olyan jellegzetes mikroszöveti bélyegeket, amelyek e kristálycsere-folyamathoz köthetők a benyomuló és a befogadó magma, illetve a benyomuló magma és a feltépett kumulátumok között: a különféle zónásságot mutató és különbözőzárványgazdag plagioklászok, az amfibolköpennyel rendelkező piroxének és a plagioklászokban megjelenő tűs apatit kristályok. A jelen tanulmányban bemutatott részletes petrográfiai vizsgálatok rávilágítanak a Ditrói alkáli masszívum magmatározóinak összetett és változatos fejlődéstörténetére, amelyben meghatározó szerepet játszottak a nyílt rendszerű magmás folyamatok.
11
Downes, H. "Magma mixing in undersaturated alkaline volcanics, Cantal, Massif Central, France." Mineralogical Magazine 53, no. 369 (March 1989): 43–53. http://dx.doi.org/10.1180/minmag.1989.053.369.04.
Full textAbstract:
AbstractSeveral examples of magma mixing exist within the undersaturated alkaline magma series of the Tertiary/Quaternary volcanics in the French Massif Central. This study describes magma mixing in the Puy Griou/Griounot area of the Cantal volcano (10-3 Ma). Petrographic evidence for injection of blebs of basic magma into phonolitic host magmas is abundant (cauliform inclusions, liquid-liquid contacts, vesiculation and chilling). Compositions of the inclusions are basic tephrite, whereas the hosts are miaskitic phonolites. Petrographic examination reveals the presence of disequilibrium mineralogical features (e.g. Mg-rich olivine in phonolites) and strong zoning in many clinopyroxenes. Transfer of phenocrysts between basic inclusions and phonolite hosts was common, and can be seen clearly in the wide range of compositions of clinopyroxene. Hornblende, magnetite and olivine were also transferred from inclusions to host.Sr and Nd isotope data indicate that, unlike most other fractionated magmas of the region, phonolites which show evidence for magma mixing are uncontaminated by the continental crust and have isotopic ratios similar to local primitive basic magmas. This leads to the suggestion that the magma mixing event took place at great depth, rather than being a high-level phenomenon. The phonolites were thus generated by high-pressure fractional crystallisation of an earlier basanitic or tephritic parent, perhaps at upper-mantle depths. This conclusion may explain why some phonolites elsewhere in the world have entrained spinel Iherzolite mantle xenoliths.
12
Kutilin, D. S., and Kh A. Mogushkova. "EFFECT OF ANTHRACYCLINE ANTITUMOR ANTIBIOTICS UPON TRANSCRIPTION ACTIVITY OF CANCER-TESTIS ANTIGENS IN MODEL EXPERIMENTS WITH HeLa CELLS." Medical Immunology (Russia) 21, no. 3 (July 13, 2019): 539–46. http://dx.doi.org/10.15789/1563-0625-2019-3-539-546.
Full textAbstract:
Cancer-testis antigens (CTA) can be used as a target for immunotherapy of various malignant tumors, including cervical cancer. However, immunotherapy is often used in combination with anthracycline chemotherapy, in particular, doxorubicin (DXR). Their effects upon expression of CTA genes have not been yet studied. Therefore, we studied the effects of doxorubicin at different concentrations and exposure time upon transcriptional profile of 17 cancer-testicular (CT) genes of HeLa CCL-2 cells. A long-term line of human cervical cancer cells (HeLa CCL-2 line) was used in this work. Culturing of HeLa CCL-2 cells was carried out in sterile culture flasks with adhesive surface and ventilated lids at 5% CO2, and 95% humidity at 37 °C, in RPMI-1640 medium with 10% fetal bovine serum, supplied with gentamicin (50 μg/ml), and different concentrations of doxorubicin: 0 μg/ml (control), 2 μg/ml, and 4 μg/ml. Expression levels of 16 RT-genes were determined by quantitative RT-PCR using a Bio-Rad CFX96 thermal cycler. Normalization of results was performed against a reference gene, and expression of tested genes in the control samples. We have found that the time of in vitroexposure, and concentration of doxorubicin exert a significant influence upon expression ofMAGEA1, MAGEA3, MAGEA4, MAGEB1, MAGEB2, GAGE1, GAGE3, BAGE, CTAG1B, XAGE3, NY-ESO1, PRAME1andSYCP1genes, however, without affecting theSSX2, MAGEA2, GAGE4andMAGEC1expression, and DXR concentration as a single factor did not affectMAGEB1andMAGEB2expression. Time of response to DXR effects enabled us to discern early cancer testicular genes with increased expression (MAGEA1, MAGEA3, MAGEA4, NY-ESO1, SYCP1), reduced expression (GAGE1andBAGE), and late inducible testicular genes (GAGE3andXAGE3). These results must be taken into account when carrying out immunotherapy based on the dendritic-cell vaccine technology.
13
Perry, Michael D., P. Lewis White, and Rosemary A. Barnes. "Comparison of four automated nucleic acid extraction platforms for the recovery of DNA from Aspergillus fumigatus." Journal of Medical Microbiology 63, no. 9 (September 1, 2014): 1160–66. http://dx.doi.org/10.1099/jmm.0.076315-0.
Full textAbstract:
Invasive aspergillosis is a significant cause of morbidity and mortality within at-risk groups. Directed antifungal chemotherapy, guided by effective screening algorithms that incorporate reliable and validated molecular assays, reduces the morbidity associated with empirical administration and allows earlier diagnosis. The efficient extraction of nucleic acid from Aspergillus fumigatus is the main limiting factor for successful Aspergillus PCR from clinical specimens. With the integration of automated extraction platforms, assessment of the suitability of these platforms for specific targets is of paramount importance. In this study, four extraction robots (Applied Biosystems MagMAX, bioMérieux easyMAG, Qiagen EZ1 and Roche MagNA Pure LC) were evaluated for their ability to extract clinically significant levels of A. fumigatus from blood. All of the platforms could detect 101 c.f.u. ml−1 from EDTA whole blood, although only the easyMAG, EZ1 and MagNA Pure had 100 % reproducibility at this level. Despite good analytical sensitivity, contamination associated with the easyMAG platform excluded its use for diagnostic Aspergillus PCR. The EZ1 and MagNA Pure platforms demonstrated equivalent high sensitivity and negative predictive values (97.4–100 %), essential for screening assays.
14
Koyaguchi, Takehiro, and Katsuya Kaneko. "Thermal evolution of silicic magma chambers after basalt replenishments." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 91, no. 1-2 (2000): 47–60. http://dx.doi.org/10.1017/s0263593300007288.
Full textAbstract:
In order to understand the governing factors of petrological features of erupted magmas of island-arc or continental volcanoes, thermal fluctuations of subvolcanic silicic magma chambers caused by intermittent basalt replenishments are investigated from the theoretical viewpoint. When basaltic magmas are repeatedly emplaced into continental crust, a long-lived silicic magma chamber may form. A silicic magma chamber within surrounding crust is composed of crystal-melt mixtures with variable melt fractions. We define the region which behaves as a liquid in a mechanical sense (‘liquid part’) and the region which is in the critical state between liquid and solid states (‘mush’) collectively as a magma chamber in this study. Such a magma chamber is surrounded by partially molten solid with lower melt fractions. Erupted magmas are considered to be derived from the liquid part. The size of a silicic magma chamber is determined by the long-term balance between heat supply from basalt and heat loss by conduction, while the temperature and the volume of the liquid part fluctuate in response to individual basalt inputs. Thermal evolution of a silicic magma chamber after each basalt input is divided into two stages. In the first stage, the liquid part rapidly propagates within the magma chamber by melting the silicic mush, and its temperature rises above and decays back to the effective fusion temperature of the crystal-melt mixture on a short timescale. In some cases the liquid part no longer exists. In the second stage, the liquid part ceases to propagate and cools slowly by heat conduction on a much longer timescale. The petrological features of the liquid part, such as the amount of unmelted preexisting crystals, depend on the intensity of individual pulses of the basalt heat source and the degree of fractionation during the first stage, as well as the bulk composition of the silicic magma.
15
Aalto, Kenneth. "A Natural Order of Volcanic Succession: Midnineteenth-Century Field-based Models of Von Richthofen, King, and Dutton." Earth Sciences History 27, no. 1 (January 1, 2008): 59–77. http://dx.doi.org/10.17704/eshi.27.1.n6682008250q2315.
Full textAbstract:
During the latter half of the nineteenth century, pioneering studies of volcanic rocks were undertaken by Ferdinand von Richthofen, Clarence King, and Clarence Dutton in the Great Basin and California Cascades. They developed hypotheses on the petrogenesis of magmas in order to explain what they deemed to be a regular progression of volcanic rock types through time during the Cenozoic Era. There was general agreement that effusive volcanism resulted in an orderly sequence of magmas: propylitic, andesitic, trachytic, rhyolitic, and basaltic. Von Richthofen related this phenomenon to the tapping of magma sources at ever-greater depths during orogenic activity, the basic magmas being denser and occupying a lower level within the Earth. King felt that so-called ‘lakes of fusion’ developed within the Earth as a result of erosional unloading of its crust; and that within such lakes gravity separation resulted in silicic magmas floating upon basic. In the secular refrigeration of the globe these temporary lakes would necessarily occur successively at greater and greater depths and the secular changes that recorded themselves in the subtle petrographical distinctions by which the various acidic and basic members could be distinguished were in each case an expression of depth. Dutton, by contrast, saw no connection between unloading and volcanism and established a modified model for the genesis of magma, emphasizing the importance of magma provenance being controlled by the fusion of variable source rocks. All felt that such temporal changes in magma type were universal and provided a basis for a natural classification of volcanic rocks.
16
Nizametdinov, I. R., D. V. Kuzmin, S. Z. Smirnov, A. V. Rybin, and I. Yu Kulakov. "Water in parental basaltic magmasof the Menshiy Brat volcano (Iturup Island, Kurile islands)." Доклады Академии наук 486, no. 1 (May 10, 2019): 93–97. http://dx.doi.org/10.31857/s0869-5652486193-97.
Full textAbstract:
The paper presents study of the liquidus assemblage of olivine and spinel in high-magnesian basalts (MgO up to 10 mas. %) of the Menshiy Brat volcano (Iturup Island). It was possible to reconstruct the water content and evolution of volatile components in the primary parental magmas that took part in the formation of the Medvezhya Caldera, Iturup Islands. It is shown that the initial water content in the primary melts could reach 5 mas. % with oxygen fugacity corresponding to oxygen buffer NNO + 0.4 log. units. The evolution of magmas involved continuous degassing while magma rises to the surface. The water-rich fluid, which is constantly separated by evolving magma, could play a significant role in the formation of large siliceous magma chambers, which participated in catastrophic caldera eruptions.
17
Cao, Yonghua, Christina Yan Wang, and Bo Wei. "Magma oxygen fugacity of mafic-ultramafic intrusions in convergent margin settings: Insights for the role of magma oxidation states on magmatic Ni-Cu sulfide mineralization." American Mineralogist 105, no. 12 (December 1, 2020): 1841–56. http://dx.doi.org/10.2138/am-2020-7351.
Full textAbstract:
Abstract Oxygen fugacities (fO2) of mantle-derived mafic magmas have important controls on the sulfur status and solubility of the magmas, which are key factors to the formation of magmatic Ni-Cu sulfide deposits, particularly those in convergent margin settings. To investigate the fO2 of mafic magmas related to Ni-Cu sulfide deposits in convergent margin settings, we obtained the magma fO2 of several Ni-Cu sulfide-bearing mafic-ultramafic intrusions in the Central Asian Orogenic Belt (CAOB), North China, based on the olivine-spinel oxygen barometer and the modeling of V partitioning between olivine and melt. We also calculated the mantle fO2 on the basis of V/Sc ratios of primary magmas of these intrusions. Ni-Cu sulfide-bearing mafic-ultramafic intrusions in the CAOB include arc-related Silurian-Carboniferous ones and post-collisional Permian-Triassic ones. Arc-related intrusions formed before the closure of the paleo-Asian ocean and include the Jinbulake, Heishan, Kuwei, and Erbutu intrusions. Post-collisional intrusions were emplaced in extensional settings after the closure of the paleo-Asian ocean and include the Kalatongke, Baixintan, Huangshandong, Huangshan, Poyi, Poshi, Tulaergen, and Hongqiling No. 7 intrusions. It is clear that the magma fO2 values of all these intrusions in both settings range mostly from FMQ+0.5 (FMQ means fayalite-magnetite-quartz oxygen buffer) to FMQ+3 and are generally elevated with the fractionation of magmas, much higher than that of MORBs (FMQ-1 to FMQ+0.5). However, the mantle fO2 values of these intrusions vary from ~FMQ to ~FMQ+1.0, just slightly higher than that of mid-ocean ridge basalts (MORBs) (≤FMQ). This slight difference is interpreted as the intrusions in the CAOB may have been derived from the metasomatized mantle wedges where only minor slab-derived, oxidized components were involved. Therefore, the high-magma fO2 values of most Ni-Cu sulfide-bearing mafic-ultramafic intrusions in the CAOB were attributed to the fractionation of magmas derived from the slightly oxidized metasomatized mantle. In addition, the intrusions that host economic Ni-Cu sulfide deposits in the CAOB usually have magma fO2 of >FMQ+1.0 and sulfides with mantle-like δ34S values (–1.0 to +1.1‰), indicating that the oxidized mafic magmas may be able to dissolve enough mantle-derived sulfur to form economic Ni-Cu sulfide deposits. Oxidized mafic magmas derived from metasomatized mantle sources may be an important feature of major orogenic belts.
18
CHRISTIANSEN, ERIC H. "Contrasting processes in silicic magma chambers: evidence from very large volume ignimbrites." Geological Magazine 142, no. 6 (November 2005): 669–81. http://dx.doi.org/10.1017/s0016756805001445.
Full textAbstract:
Very large volume (>1000 km3 of magma) crystal-rich dacitic ignimbrites that lack pronounced evidence of fractional crystallization or vertical zonation erupt in some continental magmatic arcs (e.g. the Lund Tuff of the Great Basin and the Fish Canyon Tuff of Colorado in western USA). Apparently, their magma chambers were only modestly heterogeneous and not systematically zoned from top to bottom. These ignimbrites have 40 to 50% phenocrysts set in a high-silica rhyolite glass. Mineral assemblages and mineral compositions suggest pre-eruption temperatures were 730 to 820°C and water and oxygen fugacities were relatively high. We have speculated that these very large volume ignimbrites are unzoned because crystallization and convection in slab-shaped magma chambers inhibited separation of crystals from liquids and resulted in a chamber filled with compositionally heterogeneous magma that lacked systematic chemical zonation or strong fractionation. However, many other very large volume silicic ignimbrites are strongly fractionated and may be vertically zoned (e.g. tuffs related to the Yellowstone hotspot). These rhyolitic tuffs typically have few phenocrysts, anhydrous mineral assemblages, low oxygen fugacities, crystallization temperatures of 830 to 1050°C, and a strong imprint of fractional crystallization. Yet these Yellowstone-type rhyolites are derived from chambers 40 to 70 km across which have sill-like shapes (depth/diameter ratios much less than 1). Thus, factors other than chamber shape must be important for establishing the degree of evolution and nature of zonation in silicic magma chambers. Here, the role of crystallinity-dependent viscosity on the evolution of these two types of contrasting magmas is explored. Calculated magma viscosities for the hot, dry, crystal-poor rhyolites are significantly lower than for the cooler, wetter, crystal-rich dacites. Perhaps these hot rhyolites had low enough crystal contents and viscosities to allow efficient crystal–liquid separation, probably by a combination of unhindered crystal-settling, floor crystallization (including compaction), and crystallization on the walls of large chambers. Clean separation of melt from residual solids at their sources may have been promoted by their high temperatures and low viscosities (<104.5 Pa s). In contrast, monotonous dacitic magmas may never have been crystal-free near-liquidus magmas. Their large magma chambers may have developed by progressive growth at a shallow level with repeated input of intermediate to silicic magma. Crystallization of the water-enriched dacitic magmas occurred at lower temperatures (<800 °C) where crystallinity and hence magma viscosity (>106.5 Pa s) were significantly higher. These characteristics inhibited all forms of crystal–liquid separation, hindered development of systematic vertical zonation, and promoted quasi-equilibrium crystallization in small domains within large heterogeneous magma chambers. Eruptions of these crystal-rich dacites may only occur if the roof fails over a growing magma chamber that is becoming increasingly molten.
19
Chalokwu, Christopher I., and Pamela J. Seney. "Open-system magma chamber process in the Freetown Complex of Sierra Leone: evidence from Zone 3." Geological Magazine 132, no. 3 (May 1995): 261–66. http://dx.doi.org/10.1017/s0016756800013595.
Full textAbstract:
AbstractThe ˜ 7 km thick Freetown layered complex of Sierra Leone consists of four zones each composed of a cyclically layered sequence of troctolite, gabbro, olivine gabbro, gabbronorite, and anorthosite. The complex is thought by previous workers to have solidified in situ from a single parental magma without stratigraphic changes in mineral compositions. Evidence for cryptic variation is presented based on electron microprobe analyses of mega-unit Zone 3. Two reversals in olivine forsterite content, plagioclase anorthite content, and 100 Mg/(Mg Fe2) in clinopyroxene match the variations of Ni in olivine and Cr in clinopyroxene. These changes are consistent with a magma chamber that was open to periodic influxes of new magmas, and the mixing of new and fractionated resident magmas. Expansion of the magma chamber is thought to have occurred at 2000 m, corresponding to the level of a major influx.
20
Sawyer, E. W. "Melt segregation and magma flow in migmatites: implications for the generation of granite magmas." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 87, no. 1-2 (1996): 85–94. http://dx.doi.org/10.1017/s0263593300006507.
Full textAbstract:
ABSTRACT:To form a granite pluton, the felsic melt produced by partial melting of the middle and lower continental crust must separate from its source and residuum. This can happen in three ways: (1) simple melt segregation, where only the melt fraction moves; (2) magma mobility, in which all the melt and residuum move together; and (3) magma mobility with melt segregation, in which the melt and residuum move together as a magma, but become separated during flow. The first mechanism applies to metatexite migmatites and the other two to diatexite migmatites, but the primary driving forces for each are deviatoric stresses related to regional-scale deformation. Neither of the first two mechanisms generates parental granite magmas. In the first mechanism segregation is so effective that the resulting magmas are too depleted in FeOT, MgO, Rb, Zr, Th and the REEs, and in the second no segregation occurs. Only the third mechanism produces magmas with compositions comparable with parental granites, and occurs at a large enough scale in the highest grade parts of migmatite terranes, to be considered representative of the segregation processes occurring in the source regions of granites.
21
Walker, Brett H., Michael O. Garcia, and Tim R. Orr. "Petrologic Insights into Rift Zone Magmatic Interactions from the 2011 Eruption of Kīlauea Volcano, Hawaiʻi." Journal of Petrology 60, no. 11 (November 1, 2019): 2051–75. http://dx.doi.org/10.1093/petrology/egz064.
Full textAbstract:
Abstract The high frequency of historical eruptions at Kīlauea Volcano presents an exceptional opportunity to address fundamental questions related to the transport, storage, and interaction of magmas within rift zones. The Nāpau Crater area on Kīlauea’s East Rift Zone (ERZ) experienced nine fissure eruptions within 50 years (1961–2011). Most of the magma intruded during these frequent eruptions remained stored within the rift zone, creating a potential magma mixing depot within the ERZ. The superbly monitored and sampled 2011 eruption (Puʻu ʻŌʻō episode 59) presents an extraordinary opportunity to evaluate magma mixing processes within the ERZ. Whole-rock, glass, and olivine compositions were determined, not only for lava from the 2011 eruption, but also for a new suite of Nāpau Crater area samples from the 1963, 1965, 1968, 1983, and 1997 eruptions, as well as the previously undocumented 1922 eruption. Whole-rock XRF data revealed two geochemically distinct magma batches for episode 59: one less evolved (∼6·6 wt % MgO, 0·46 wt % K2O) than the other (∼6·2 wt % MgO, 0·58 wt % K2O). Episode 59 lava is remarkably aphyric (∼0·1 vol. % phenocrysts), making use of mineralogy to identify parent magma affinities problematic. Linear compositional trends of whole-rock major and trace elements, and reversely zoned olivine crystals indicate episode 59 lavas underwent magma mixing. Least squares regression calculations and plots of major and trace element data, were used to evaluate whether the episode 59 samples are products of mixing summit-derived magma with residual magma from previous Nāpau Crater area eruptions. The regression results and trace element ratios are inconsistent with previously proposed mixing scenarios, but they do support mixing between summit-derived magma and residual magma from the 1983 and 1997 Nāpau Crater area eruptions. These magmas were stored in physically and chemically distinct pods at depths of 1·6–3·0 km prior to mixing with new magma intruded from the summit to produce the episode 59 lava. One pod contained a fractionated equivalent of 1983 lava, and the other a hybrid of compositions similar to 1983 and 1997 lavas. The petrology of episode 59 lava demonstrates that magmas from two previous eruptions (1983 and 1997) were available to mix with magma intruded from the summit region. This study clarifies the pre-eruptive history of the mixed episode 59 lava, and elucidates the evolution of the volcano's magmatic system in a region of frequent eruptions.
22
Pleško, I. Mavrič, M. Viršček Marn, G. Seljak, and I. Žežlina. "First Report of Grapevine Pinot gris virus Infecting Grapevine in Slovenia." Plant Disease 98, no. 7 (July 2014): 1014. http://dx.doi.org/10.1094/pdis-11-13-1137-pdn.
Full textAbstract:
Unusual virus-like symptoms were first observed in 2001 on grapevine cvs. Pinot gris and Sauvignonasse in vineyards from the western part of Slovenia. Symptomatic plants showed shortened internodes, poor leaf development, mottling, and deformations of leaves that resulted in poor growth of symptomatic plants. In 2003 and 2004, several samples were tested for Arabis mosaic virus, Cherry leafroll virus, Grapevine fanleaf virus, Raspberry bushy dwarf virus, Strawberry latent ringspot virus, Tomato black ring virus, Tomato ringspot virus, and Tobacco ringspot virus by DAS-ELISA, but none of them could be confirmed as the cause of the observed symptoms. During intensive visual inspections between 2002 and 2006, the symptoms were observed on most grapevine cultivars grown in the Primorska region but predominantly on the two previously mentioned cultivars. In Trentino, northern Italy, similar virus-like symptoms, i.e., chlorotic mottling, puckering and deformation of the leaves, reduced yield, and low quality of the berries were observed in grapevine plants cv. Pinot gris in 2003 and in cvs. Traminer and Pinot noir in 2009 (2). No common grapevine viruses could be associated with the disease. In 2012, a new trichovirus named Grapevine Pinot gris virus (GPGV) was found in Pinot gris plants using deep sequencing. The virus was also detected in symptomless plants (2). GPGV was later reported also from Korea causing inner necrosis of berries and poor fruit set in grapevine cv. Tamnara (1). In 2012, 42 leaf samples from mostly symptomatic grapevine plants of cvs. Pinot gris, Pinot noir, and Muscat blanc were collected at three locations in the Primorska region. Total RNA was extracted from leaves using the MagMAX Express magnetic particle processor with MagMAX-96 Total RNA Isolation Kit and Plant RNA Isolation Aid in Lysis Binding Solution Concentrate (all by Life Technologies, Grand Island, NY). DNA fragments of 1,049 bp corresponding to the movement protein gene were successfully amplified by RT-PCR from 40 samples using primers GPgV5619 and GPgV6668 (2). Amplification products from three plants were cloned into the pGEM-T Easy vector (Promega, Madison, WI) and sequenced. The sequences were deposited in the EBI database under the accession numbers HG738850 to 52. All the nucleotide sequences shared 97.4 to 97.6% identity with GPGV from Italy (sequence FR877530) and 97.1 to 98.2% amino acid identity within the translated region. To our knowledge, this is the first report of GPGV in Slovenia. The disease seems to be spreading extensively in the Primorska region, causing considerable economic losses, and in 2013 it was also observed in other regions of Slovenia. Since the virus could be found in symptomless plants in Italy and in Slovenia, its role in the development of the disease should be further investigated. References: (1) I. S. Cho et al. New Dis. Rep. 27:10, 2013. (2) A. Giampetruzzi et al. Virus Res. 163:262, 2012.
23
Metcalf, Rodney V. "Volcanic–plutonic links, plutons as magma chambers and crust–mantle interaction: a lithospheric scale view of magma systems." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 95, no. 1-2 (March 2004): 357–74. http://dx.doi.org/10.1017/s0263593300001127.
Full textAbstract:
ABSTRACTThe northern Colorado River extensional corridor (NCREC, USA) provides an excellent record of coeval volcanic and mid- to upper-crustal (<13 km) plutonic suites. The NCREC is a 50–100-km-wide zone that records late Tertiary lithospheric extension, volcanism, continental sedimentation and plutonism. Compilation of published studies of NCREC magmatic rocks permits an assessment of volcanic–plutonic links, magma sources and magmatic processes. The volcanic sections provide an excellent record of magma compositions (basalt, trachyandesite, trachyte and rhyolite) which span a 9-million-year period in the Miocene age (20–11 Ma).Contemporaneous Miocene plutons span a similar compositional range (gabbro, diorite, quartz monzonite and granite) and were emplaced during a 4·5-million-year interval from 17 to 12·5 Ma. Geochemical and isotopic compositions and compositional trends allow direct correlation between plutonic and volcanic suites across the entire compositional range. Petrogenetic models demonstrate that intermediate magmas formed by a combination of magma mixing and fractional crystallisation involving mantle-derived mafic with crustal-derived felsic end-member magmas. Plutons exhibit a variety of features which suggest magma chamber processes, including (1) mafic cumulate sequences, (2) felsic cumulate sequences, and (3) magma mingling and advanced stages of magma mixing. Thus, the NCREC plutonic-volcanic record provides a link between magmatic processes recorded in pluton magma chambers and magmatic products in the form of extrusive igneous rocks. The NCREC plutons represent upper crustal magma chambers which connected volcanic eruptive centres to deeper-level magma chambers, and ultimately, to zones of mantle and crustal mel
24
Cox, Daniel, Sebastian F. L. Watt, Frances E. Jenner, Alan R. Hastie, Samantha J. Hammond, and Barbara E. Kunz. "Elevated magma fluxes deliver high-Cu magmas to the upper crust." Geology 48, no. 10 (June 10, 2020): 957–60. http://dx.doi.org/10.1130/g47562.1.
Full textAbstract:
Abstract Porphyry Cu-Au ore deposits are globally associated with convergent margins. However, controls on the processing and distribution of the chalcophile elements (e.g., Cu) during convergent margin magmatism remain disputed. Here, we show that magmas feeding many Chilean stratovolcanoes fractionate sulfides with a high-Cu/Ag ratio early in their crustal evolution. These magmas show evidence of lower-crustal garnet and amphibole crystallization, and their degree of sulfide fractionation and Cu depletion increase with both crustal thickness and the extent of garnet fractionation. However, samples from a small proportion of volcanoes with elevated eruptive fluxes depart from this Cu-depleting trend, instead erupting Cu-rich magmas. This implies that at these atypical sites, elevated magma productivity and crustal throughput, potentially facilitated by “pathways” exploiting major crustal fault systems, enable rapid magma transit, avoiding lower-crustal Cu-depleting sulfide fractionation and potentially playing an important role in porphyry ore genesis.
25
Conway, Chris E., Katy J. Chamberlain, Yumiko Harigane, Daniel J. Morgan, and Colin J. N. Wilson. "Rapid assembly of high-Mg andesites and dacites by magma mixing at a continental arc stratovolcano." Geology 48, no. 10 (June 25, 2020): 1033–37. http://dx.doi.org/10.1130/g47614.1.
Full textAbstract:
Abstract Studies of pre-eruptive processes at active volcanoes require precise petrochronological constraints if they are to contribute to hazard assessment during future eruption events. We present petrological and geochemical data and orthopyroxene diffusion time scales for samples from Late Pleistocene high-Mg andesite-dacite lavas (Mg# 53–69) at Ruapehu volcano, New Zealand, as a case study of rapid magma genesis and eruption at a continental arc stratovolcano. Assembly of Ruapehu high-Mg magmas involved the mixing of primitive magmas plus entrained mantle-equilibrated olivines with mid-crustal felsic mush bodies, yielding hybridized magmas with ubiquitous pyroxene reverse-zoning patterns. Orthopyroxene Fe-Mg interdiffusion time scales linked to quantitative crystal orientation data show that most lavas erupted <10 days after resumption of crystal growth following magma mixing events. The eruption of lavas within days of mixing events implies that pre-eruptive warnings may be correspondingly short.
26
Sun, Jing-gui, Yun-peng He, Ji-long Han, and Zhong-yu Wang. "Genesis of the Wuxing Pt–Pd-rich Cu–Ni sulfide deposit in the eastern Central Asian Orogenic Belt: evidences from geochronology, elemental geochemistry, and Sr–Nd–Hf isotopic data." Canadian Journal of Earth Sciences 56, no. 4 (April 2019): 380–98. http://dx.doi.org/10.1139/cjes-2018-0233.
Full textAbstract:
The Wuxing Pt–Pd-rich Cu–Ni sulfide deposit in Heilongjiang Province, Northeast China, is located to the northeast of the Dunhua–Mishan fracture of the eastern Central Asian Orogenic Belt. The mafic–ultramafic complex consist of early-period hornblende–olivine pyroxenite, diopsidite, and hornblende pyroxenite and late-period gabbro and diabase units. An early-period hornblende pyroxenite yielded a zircon U–Pb age of 208.2 ± 2.6 Ma and a late-period diabase yielded a U–Pb age of 205.6 ± 1.1 Ma, with zircon εHf(t) values of +1.24 to +8.13. The early- and late-period lithofacies are relatively enriched in LILE (Rb, Ba, and Sr) and LREE, and variably depleted in HFSE (Nb, Ta). The whole-rock and single-mineral analyses of the early-period lithofacies yield (87Sr/86Sr)i ratios of 0.7055–0.7083 and εNd(t) ratios of −7.98–+3.10. These geochemical data suggest that the parental magmas of the Wuxing complex are high-Mg subalkaline basaltic in nature and were derived from an enriched mantle source. The magmas chamber formed after the injection of magma into the crust along with crustal contamination, producing early crystalline minerals and ore-bearing magmas. The rupturing of the magma chamber released evolved magmas, which then ascended and generated Pt–Pd-bearing lithofacies and Cu–Ni sulfide orebodies by fractional crystallization, accumulation, and liquation. During the late period, the residual magma invaded the early lithofacies and Cu–Ni orebodies. The fluids exsolved from the gabbroic magmas concentrated the mineralized metal elements and enhanced the precipitation of Pt–Pd-bearing veinlet-disseminated orebodies and Pt–Pd–Cu–Ni orebodies.
27
DePaolo, Donald J., Frank V. Perry, and W. Scott Baldridge. "Crustal versus mantle sources of granitic magmas: a two-parameter model based on Nd isotopic studies." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 83, no. 1-2 (1992): 439–46. http://dx.doi.org/10.1017/s0263593300008117.
Full textAbstract:
ABSTRACTTemporal and spatial variations in the Nd isotopic compositions of Tertiary caldera-forming rhyolite tuffs, and Cretaceous and Tertiary granites of the western U.S.A. are used as a basis for a model that accounts for the observed proportions of crustal versus mantle contributions to silicic magmas in terms of two parameters: the ambient crustal temperature and the rate of supply of basaltic magma from the mantle. The crustal contribution to silicic igneous rocks is measured in terms of the Neodymium Crustal Index (NCI). The relationships between crustal temperature, basalt supply and NCI are quantified using a model of a magma chamber undergoing continuous recharge, wall-rock assimilation and fractional crystallisation. From the model, a critical value of the ratio of basalt recharge-to-assimilation, (r/a)c, is deduced, which increases with decreasing crustal temperature. The r/a value must exceed (r/a)c to allow the volume of differentiated magma to increase, a prerequisite for developing large volumes of silicic magma. Strongly peraluminous (or S-type) magmas (NCI = 0·8–1), form under conditions of high crustal temperature and low basalt supply. Metaluminous or I-type granites form over a wide range of conditions (NCI = 0·1–1), generally where basalt supply is substantial. In individual long-lived volcanic centres, the large-volume high-silica ignimbrites are associated with the highest r/a and lowest NCI values, indicating that these magmas are typically differentiates of mantle-derived basaltic parents.
28
Woolley, Alan R., and R. Garth Platt. "The mineralogy of nepheline syenite complexes from the northern part of the Chilwa Province, Malawi." Mineralogical Magazine 50, no. 358 (December 1986): 597–610. http://dx.doi.org/10.1180/minmag.1986.050.358.05.
Full textAbstract:
AbstractThe mineralogy, including the accessory phases låvenite, rosenbuschite, and catapleiite, and consequent petrogenetic implications have been investigated for a group of four overlapping nepheline syenite complexes (Chikala, Chaone, Mongolowe, and Chinduzi) and for spatially associated silica-saturated and over-saturated perthosites, from the northern part of the Chilwa Alkaline Province, Malawi.The complexes are thought to have formed by injection into high-level chambers of magma pulses genetically related to a common source magma at depth. Evidence for the source magma is preserved in salitic cores observed in the pyroxenes and a trend to more hedenbergite-rich compositions is believed to have formed by evolution of this magma. Subsequent trends of acmite enrichment followed magma injection into the higher-level chambers; the actual pyroxene trend associated with each individual complex is a function of the evolution attained by the source magma, oxidation potential, and perhaps even alkali activity. On the basis of such a two-stage model, the pyroxene data suggest emplacement of the Chaone and Mongolowe magmas somewhat earlier than that of Chikala, with the Chinduzi magma migrating even later.Amphiboles and biotites are believed to have formed after high-level injection of the magmas. Their compositions broadly reflect the nature of the crystallizing pyroxenes in that magnesian hastingsitic hornblendes and more Mg-rich biotites are associated with more Mg-rich sodic pyroxenes, whereas katophorites and annite-rich micas are generally associated with sodic pyroxenes somewhat richer in hedenbergite. Sub-solidus crystallization in some of the complexes is represented by aegirine and magnesio-arfvedsonite. Nepheline compositions indicate broadly similar crystallization temperatures within the complexes, namely 950 to 750°C. Oxygen fugacities for these magmas obtained from biotite/annite compositions vary from 10−19 to 10−14 bars for this temperature range. Mineralogical data, particularly from pyroxenes and amphiboles, strongly suggest that the perthosites, spatially associated with the nepheline syenite complexes, are genetically unrelated.
29
Janoušek, Vojtěch, D. R. Bowes, Colin J. R. Braithwaite, and Graeme Rogers. "Micro structural and mineralogical evidence for limited involvement of magma mixing in the petrogenesis of a Hercynian high-K calc-alkaline intrusion: the Kozárovice granodiorite, Central Bohemian Pluton, Czech Republic." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 91, no. 1-2 (2000): 15–26. http://dx.doi.org/10.1017/s0263593300007264.
Full textAbstract:
Textural and mineralogical features in the high-K calc-alkaline Kozárovice granodiorite (Hercynian Central Bohemian Pluton, Bohemian Massif) and associated small quartz monzonite masses imply that mixing between acid (granodioritic) and basic (monzonitic/monzogabbroic) magmas was locally petrogenetically significant.Net veining, with acicular apatite and numerous lath-shaped plagioclase crystals present in the quartz monzonite, and abundant mafic microgranular enclaves (MME) in the granodiorite, indicate that as the monzonitic magma was injected into the granodioritic magma chamber, it rapidly cooled and was partly disintegrated by the melt already present. Evidence from cathodoluminescence suggests that the two magmas exchanged early-formed plagioclase crystals. In the quartz monzonite, granodiorite-derived crystals were overgrown by narrow calcic zones, followed by broad, normally zoned sodic rims. In the granodiorite, plagioclase crystals with calcic cores overgrown by normally zoned sodic rims are interpreted as xenocrysts from the monzonite. After thermal adjustment, crystallisation of the monzonitic magma ceased relatively slowly, forming quartz and K-feldspar oikocrysts.Although the whole-rock geochemistry of the quartz monzonite and the MME support magma mixing, major- and trace-element based modelling of the host granodiorite has previously indicated an origin dominated by assimilation and fractional crystallisation. Magma mixing therefore seems to represent a local modifying influence rather than the primary petrogenetic process.
30
Attia, Snir, John M. Cottle, and Scott R. Paterson. "Erupted zircon record of continental crust formation during mantle driven arc flare-ups." Geology 48, no. 5 (February 14, 2020): 446–51. http://dx.doi.org/10.1130/g46991.1.
Full textAbstract:
Abstract Coupled zircon U-Pb age, trace-element, and Lu-Hf isotope analyses from central Sierra Nevada (eastern California, USA) metavolcanic strata reveal the expression of three Mesozoic arc flare-ups in the volcanic record over ∼150 m.y. of magmatic activity. Zircon εHf(i) values vary up to 20 epsilon units within individual samples and coeval sample populations but show no clear links with other geochemical indices, requiring both mixing and fractionation for arc magma genesis. Zircon compositions show repeated temporal trends across flare-ups: Hf isotopes spanning evolved to juvenile values converge to more juvenile compositions, middle rare earth element (MREE) depletion and heavy REE slopes increase during flare-up main phases, and highly variable U/Yb values converge to low values as flare-ups conclude. Despite pervasive contamination, juvenile source magmas dominate magmas erupted throughout the entirety of high-magma-addition episodes. Arc flare-ups thus represent ∼30 m.y. of increased mantle magma input that represents significant continental crust formation in Cordilleran arcs.
31
Husakova, Marketa, Petr Kralik, Vladimir Babak, and Iva Slana. "Efficiency of DNA Isolation Methods Based on Silica Columns and Magnetic Separation Tested for the Detection of Mycobacterium avium Subsp. Paratuberculosis in Milk and Faeces." Materials 13, no. 22 (November 12, 2020): 5112. http://dx.doi.org/10.3390/ma13225112.
Full textAbstract:
Timely and reliable detection of animals shedding Mycobacterium avium subsp. paratuberculosis (MAP) should help to effectively identify infected animals and limit infection transmission at early stages to ensure effective control of paratuberculosis. The aim of the study was to compare DNA extraction methods and evaluate isolation efficiency using milk and faecal samples artificially contaminated by MAP with a focus on modern instrumental automatic DNA isolation procedures based on magnetic separation. In parallel, an automatic and manual version of magnetic separation and two methods of faecal samples preparation were compared. Commercially available DNA isolation kits were evaluated, and the selected kits were used in a trial of automatic magnetic beads-based isolation and compared with the manual version of each kit. Detection of the single copy element F57 was performed by qPCR to quantify MAP and determine the isolation efficiency. The evaluated kits showed significant differences in DNA isolation efficiencies. The best results were observed with the silica column Blood and Tissue kit for milk and Zymo Research for faeces. The highest isolation efficiency for magnetic separation was achieved with MagMAX for both matrices. The magnetic separation and silica column isolation methods used in this study represent frequently used methods in mycobacterial diagnostics.
32
Lee, Eun Young, Eun-Ju Lee, Hana Yoon, Dong Hyeon Lee, and Kwang Hyun Kim. "Comparison of Four Commercial Kits for Isolation of Urinary Cell-Free DNA and Sample Storage Conditions." Diagnostics 10, no. 4 (April 18, 2020): 234. http://dx.doi.org/10.3390/diagnostics10040234.
Full textAbstract:
Urinary cell-free DNA (cfDNA) is an attractive body fluid for liquid biopsy. In this study, we compared the efficiencies of four commercial kits for urinary cell-free DNA (cfDNA) isolation and of various sample storage conditions. Urinary cfDNA was isolated from 10 healthy individuals using four commercial kits: QIAamp Circulating Nucleic Acid Kit (QC; Qiagen), MagMAX™ Cell-Free DNA Isolation Kit (MM; Applied Biosystems), Urine Cell-Free Circulating DNA Purification Midi Kit (NU; Norgen Biotek), and Quick-DNA™ Urine Kit (ZQ; Zymo Research). To assess the isolation efficiency, an Agilent 2100 Bioanalyzer with High Sensitivity DNA chips was used, and cfDNA yield was defined as the amount of cfDNA obtained from 1 mL of urine. MM and QC provided the highest cfDNA yield in the 50–300 bp range, and MM and NU gave the highest cfDNA yield in the 50–100 bp range. In particular, the NU kit was efficient for isolation of more fragmented cfDNA in the range of 50–100 bp with the lowest cellular genomic DNA contamination. ZQ had the best cost-efficiency for isolating the same amount of urinary cfDNA. Samples stored at −70 °C with the addition of 10 mM EDTA resulted in the highest cfDNA yield 3 months after sample collection.
33
Riccardi, Marco. "Free Magmas." Formalized Mathematics 18, no. 1 (January 1, 2010): 17–26. http://dx.doi.org/10.2478/v10037-010-0003-0.
Full textAbstract:
Free Magmas This article introduces the free magma M(X) constructed on a set X [6]. Then, we formalize some theorems about M(X): if f is a function from the set X to a magma N, the free magma M(X) has a unique extension of f to a morphism of M(X) into N and every magma is isomorphic to a magma generated by a set X under a set of relators on M(X). In doing it, the article defines the stable subset under the law of composition of a magma, the submagma, the equivalence relation compatible with the law of composition and the equivalence kernel of a function. We also introduce some schemes on the recursive function.
34
Litavrin, Andrey Viktorovich. "Subsystems and Automorphisms of Some Finite Magmas of Order k + k2." Izvestiya of Saratov University. New Series. Series: Mathematics. Mechanics. Informatics 20, no. 4 (2020): 457–67. http://dx.doi.org/10.18500/1816-9791-2020-20-4-457-467.
Full textAbstract:
This work is devoted to the study of subsystems of some finite magmas S = (V, ∗) with a generating set of k elements and order k + k2. For k > 1, the magmas S are not semigroups and quasigroups. An element-by-element description of all magmas S subsystems is given. It was found that all the magmas S have subsystems that are semigroups. For k > 1, subsystems that are idempotent nonunit semigroups are explicitly indicated. Previously, a description of an automorphism group was obtained for magmas S. In particular, every symmetric permutation group Sk is isomorphic to the group of all automorphisms of a suitable magma S. In this paper, a general form of automorphism for a wider class of finite magmas of order k + k2 is obtained.
35
Fulignati, P., P. Marianelli, and A. Sbrana. "Glass-bearing felsic nodules from the crystallizing sidewalls of the 1944 Vesuvius magma chamber." Mineralogical Magazine 64, no. 3 (June 2000): 481–96. http://dx.doi.org/10.1180/002646100549373.
Full textAbstract:
AbstractIn the 1944 Vesuvius eruption, the shallow magma chamber was disrupted during the highly energetic explosive phases. Abundant cognate xenoliths such as subvolcanic fergusites and cumulates, hornfels, skarns and rare marbles occur in tephra deposits.Mineral chemistry, melt inclusions in minerals and glassy matrix compositions show that fergusites (highly crystalline rocks made of leucite, clinopyroxene, plagioclase, olivine, apatite, oxides and glass) do not correspond to melt compositions but result from combined sidewall accumulation of crystals, formed from K-tephriphonolitic magma resident in the chamber, and in situ crystallization of the intercumulus melt. Very low H2O contents in the intercumulus glass are revealed by FTIR and apatite composition. Whole rock compositions are essentially determined by the bulk mineral assemblages.Glass–bearing fergusites constitute the outer shell of the magma chamber consisting of a highly viscous crystal mush with a melt content in the range 20–50 wt.%. The leucite/(clinopyroxene+olivine) modal ratio, varies with the extraction order of magmas from the chamber, decreasing upwards in the stratigraphic sequence. This reflects a vertical mineralogical zonation of the crystal mush. These data contribute to the interpretation of the subvolcanic low–pressure crystallization processes at the magma chamber sidewalls affecting alkaline potassic magmas.
36
Tsvetov, V. P. "FRACTAL MAGMAS AND PUBLIC-KEY CRYPTOGRAPHY." Vestnik of Samara University. Natural Science Series 26, no. 2 (February 1, 2021): 23–49. http://dx.doi.org/10.18287/2541-7525-2020-26-2-23-49.
Full textAbstract:
In this paper, we deal with magmas the simplest algebras with a single binary operation. The main result of our research is algorithms for generating chain of finite magmas based on the self-similarity principle of its Cayley tables. In this way the cardinality of a magmas domain is twice as large as the previous one for each magma in the chain, and its Cayley table has a block-like structure. As an example, we consider a cyclic semigroup of binary operations generated by a finite magmas operation with a low-cardinality domain, and a modify the Diffie-Hellman-Merkle key exchange protocol for this case.
37
Barbarin, Bernard, and Jean Didier. "Genesis and evolution of mafic microgranular enclaves through various types of interaction between coexisting felsic and mafic magmas." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 83, no. 1-2 (1992): 145–53. http://dx.doi.org/10.1017/s0263593300007835.
Full textAbstract:
ABSTRACTThermal, mechanical and chemical exchange occurs between felsic and mafic magmas in dynamic magma systems. The occurrence and efficiency of such exchanges are constrained mainly by the intensive parameters, the compositions, and the mass fractions of the coexisting magmas. As these interacting parameters do not change simultaneously during the evolution of the granite systems, the exchanges appear sequentially, and affect magmatic systems at different structural levels, i.e. in magma chambers at depth, in the conduits, or after emplacement. Hybridisation processes are especially effective in the plutonic environment because contrasting magmas can interact over a long time-span before cooling. The different exchanges are complementary and tend to reduce the contrasts between the coexisting magmas. They can be extensive or limited in space and time; they are either combined into mixing processes which produce homogeneous rocks, or only into mingling processes which produce rocks with heterogeneities of various size-scales. Mafic microgranular enclaves represent the most common heterogeneities present in the granite plutons. The composite enclaves and the many types of mafic microgranular enclaves commonly associated in a single pluton, or in polygenic enclave swarms, are produced by the sequential occurrence of various exchanges between coexisting magmas with constantly changing intensive parameters and mass fractions. The complex succession and repetition of exchanges, and the resulting partial chemical and complete isotopic equilibration, mask the original identities of the initial components.
38
Thy, P. "Magmas and magma chamber evolution, Troodos ophiolite, Cyprus." Geology 15, no. 4 (1987): 316. http://dx.doi.org/10.1130/0091-7613(1987)15<316:mamcet>2.0.co;2.
Full text
39
Harangi, Szabolcs, and Réka Lukács. "A Kárpát-Pannon térség neogén-kvarter vulkanizmusa és geodinamikai kapcsolata." Földtani Közlöny 149, no. 3 (September 24, 2019): 197. http://dx.doi.org/10.23928/foldt.kozl.2019.149.3.197.
Full textAbstract:
A Kárpát-Pannon térség neogén-kvarter vulkáni működése szorosan kapcsolódik a térség geodinamikai fejlődéséhez. Horváth Ferenc professzor munkássága, ösztönzése nagy mértékben segített abban, hogy a magmaképződés eseményeit, a vulkanizmust igyekezzünk behelyezni a tágabb lemeztektonikai környezetbe. A lemeztektonika elmélete segít abban, hogy a vulkánok elhelyezkedését, a felszínre törő magma összetételét jobban megértsük. Horváth professzor jelentős szerepet játszott abban, hogy a dinamikus Föld globális modellje hazai szinten is elfogadást kapjon és élete végéig kereste az újabb és újabb magyarázatokat, hogy feltárjuk a Pannon-medence keletkezésének okát és a kapcsolódó földtani és geofizikai eseményeket. Az elmúlt 50 év tudományos munkái azonban rámutattak arra, hogy a lemeztektonika paradigmája nem alkalmazható rutinszerűen a vulkáni működés értelmezésében és a földtudományok különböző területeit integráló kutatások szükségesek bolygónk folyamatainak jobb megismeréséhez. A vulkanizmust a forrástól a felszínig kell megértenünk, azaz megtalálni a magmaképződés okát, a magma elhelyezkedését a földkéregbe, a magmatározóban zajló folyamatokat és azok időskáláját, a vulkánkitörések okait és a vulkáni működés lefolyását. A modern geokémiai analitikai módszerek elterjedésével és az ezekhez való hozzáféréssel jelentős mennyiségű, nagy pontosságú összetétel adat áll rendelkezésünkre, amit kiegészítenek az egyre nagyobb pontosággal meghatározott geokronológiai eredmények a vulkánkitörések idejére. Mindezek megteremtik az alapot, hogy a vulkáni működés okaira következtethessünk. Habár a petrogenetikai modellek egyre jobban finomodnak, azonban ezek újabb kérdéseket is felvetnek, perspektívát adva a további kutatásoknak.A Kárpát-Pannon térség neogén-kvarter vulkáni működését négy nagyobb csoportba oszthatjuk: (1) szilíciumgazdag magmák kitörése; (2) mészalkáli bazalt-andezit-dácit-riolit vulkanizmus; (3) alkáli bazalt és trachit vulkáni működés és (4) káli-ultrakáli vulkáni kitörések. Mindegyik magmás esemény esetében a fő befolyásoló tényező a litoszféra és ezen belül a földkéreg elvékonyodása volt. A riftesedés kezdetén andezit-dácit vulkánosság zajlott (19-20 Ma), a földkéregbe nyomuló magmák átfűtötték a litoszférát, megteremtve a lehetőséget többek között arra, hogy néhány millió évvel később jelentős (több ezer) térfogatú szilíciumgazdag magma alakítson ki kiterjedt magmatározó rendszert a Pannon-medence belső területén. A több szakaszban zajló kitörések 4000 km3-t meghaladó mennyiségű vulkáni hamuanyagot hoztak a felszínre, ami alapján a földkéregben ennek többszörös mennyiségű magmás anyaga helyezkedhetett el. Mindez nagymértékben befolyásolta a földkéreg termomechanikai állapotát. A szilíciumgazdag magmák kitörésének egyik fő időszaka 17,5-14,4 millió évvel ezelőtt volt, ami Európában, az elmúlt 20 millió év legnagyobb vulkánkitöréseit eredményezte. Az új cirkon U-Pb koradatok nem csak a kitörési korokat pontosították, hanem a vulkáni működéssel egyidejű blokkforgások idejét (16,8-17,1 Ma, illetve 15-16 Ma), továbbá a magmatározók fennállási idejét is. Ez utóbbiak szerint a szilíciumgazdag magmatározók több százezer éven keresztül létezhettek a földkéreg középső-felső részén. A vulkáni hamurétegek kulcsszerepet játszanak a Paratethys üledékgyűjtők rétegsorainak korrelációjában. A mészalkáli kőzetsorozatok látszólag a Kárpátok ívét követik, azonban a fúrás adatok és a szeizmikus szelvények értelmezései rámutatnak arra, hogy jelentős mennyiségben keletkeztek a Pannon-medence belső területein is. A felszínen megjelenő vulkáni komplexumok esetében a Pannon-medence északi részén húzódó szegmens számos különbséget mutat a keleti vulkáni ághoz képest, ami eltérő képződést sejtet. Az északi szegmens vulkáni területei alapvetően a Pannon-medence fő extenziós időszakában alakultak ki. Az elsődleges magmák kezdetben a korábbi szubdukciós események során átalakult (metaszomatizálódott) földköpeny-litoszféra részleges, nyomáscsökkenéses olvadása során jöttek létre, majd 13 millió év után egy markáns változás tapasztalható a kitörő magmák összetételében, ami a forrásterület megváltozására utal. Ekkor már túlnyomórészt az asztenoszféra-földköpeny olvadása hozta létre a magmákat és vezetett később az alkáli bazalt vulkanizmushoz. A keleti szegmens vulkáni működése időben később történt egy posztkollíziós környezetben, ahol a magmák kialakulásában és felnyomulásában fontos szerepet kapott a tektonikai környezet. Az egyre délebbre húzódó transztenziós szerkezeti mozgások okozhatták a vulkáni működés dél felé fiataladó jellegét. Az alkáli bazalt vulkáni működés fő időszaka 2-5 millió évvel ezelőtt volt, jóval a fő extenziós időszak után. A vulkáni mezők elhelyezkedése és a bazaltok kémiai összetételén alapuló petrogenetikai modellszámítások azt jelzik, hogy a magmák heterogén asztenoszféra-földköpeny kis mértékű olvadása során alakultak ki. A magmaképződésben kulcsszerepet játszhatott a Pannon-medence alatt anomálisan elvékonyodott litoszféra peremi részein indukált asztenoszféra kőzetanyag feláramlás. A káliumban dús magmák erősen metaszomatizált litoszféra földköpeny olvadása során alakultak ki, részben a fő riftesedési időszakban, részben az elmúlt 2 millió évben. A fiatal káli-ultrakáli vulkáni működés a Pannon-medence déli peremére koncentrálódik és egy nyugat-keleti csapású tektonikai zónához kapcsolódik. Ekkor friss asztenoszféra anyag feláramlás hőhatása okozhatta a metaszomatizált litoszféra kis mértékű olvadását. A Kárpát-Pannon térség vulkáni működésének fő időszaka 10-17 millió éve volt, azonban még a kvarterben is tucatnyi kitörés zajlott. A legfiatalabb vulkáni működés értékelése arra hívja fel a figyelmet, hogy a térség alatti asztenoszféra kőzettani felépítése olyan, hogy még jelenleg is képes olvadásra, azaz magma keletkezhet, továbbá a geodinamikai környezet több helyen is lehetőséget adhat magma felnyomulásra és vulkánkitörésre. Mindezek fontos további perspektívát adnak, hogy Horváth professzor szellemi örökségét követve igyekezzünk még jobban megérteni térségünk geodinamikai fejlődését és jelenlegi állapotát, beleértve a vulkáni működés kapcsolatát.
40
Scaillet, Bruno, Alan Whittington, Caroline Martel, Michel Pichavant, and François Holtz. "Phase equilibrium constraints on the viscosity of silicic magmas II: implications for mafic–silicic mixing processes." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 91, no. 1-2 (2000): 61–72. http://dx.doi.org/10.1017/s026359330000729x.
Full textAbstract:
Isobaric crystallisation paths obtained from phase equilibrium experiments show that, whereas in rhyolitic compositions melt fraction trends are distinctly eutectic, dacitic and more mafic compositions have their crystallinities linearly correlated with temperatures. As a consequence, the viscosities of the latter continuously increase on cooling, whereas for the former they remain constant or even decrease during 80% of the crystallisation interval, which opens new perspectives for the fluid dynamical modelling of felsic magma chambers. Given the typical dyke widths observed for basaltic magmas, results of analogue modelling predict that injection of mafic magmas into crystallising intermediate to silicic plutons under pre-eruption conditions cannot yield homogeneous composition. Homogenisation can occur, however, if injection takes place in the early stages of magmatic evolution (i.e. at near liquidus conditions) but only in magmas of dacitic or more mafic composition. More generally, the potential for efficient mixing between silicic and mafic magmas sharing large interfaces at upper crustal levels is greater for dry basalts than for wet ones. At the other extreme, small mafic enclaves found in many granitoids behave essentially as rigid objects during a substantial part of the crystallisation interval of the host magmas, which implies that finite strain analyses carried out on such markers can give only a minimum estimate of the total amount of strain experienced by the host pluton. Mafic enclaves carried by granitic magmas behave as passive markers only at near solidus conditions, typically when the host granitic magma shows near-solid behaviour. Thus they cannot be used as fossil indicators of direction of magmatic flow.
41
Trua, Teresa, and Michael P. Marani. "Clinopyroxene Crystals in Basic Lavas of the Marsili Volcano Chronicle Early Magmatic Stages in a Back-Arc Transcrustal Mush System." Geosciences 11, no. 4 (April 1, 2021): 159. http://dx.doi.org/10.3390/geosciences11040159.
Full textAbstract:
Constraining the pre-eruptive processes that modulate the chemical evolution of erupted magmas is a challenge. An opportunity to investigate this issue is offered by the interrogation of the crystals carried in lavas. Here, we employ clinopyroxene crystals from back-arc lavas in order to identify the processes driving basalt to andesite magma evolution within a transcrustal plumbing system. The assembled clinopyroxene archive reveals that mantle melts injected at the crust-mantle transition cool and crystalize, generating a clinopyroxene-dominated mush capped by a melt-rich domain. Magma extracted from this deep storage zone fed the eruption of basalt to basaltic andesite lavas. In addition, chemically evolved melts rapidly rising from this zone briefly stalled at shallow crustal levels, sourcing crystal-poor andesite lavas. Over time, hot ascending primitive magmas intercepted and mixed with shallower cooling magma bodies forming hybrid basic lavas. The blended clinopyroxene cargoes of these lavas provide evidence for the hybridization, which is undetectable from a whole-rock chemical perspective, as mixing involved chemically similar basic magmas. The heterogeneity we found within the clinopyroxene archive is unusual since it provides, for the first time, a complete set of mush-related scenarios by which mantle melts evolve from basalt to andesite compositions. Neither the whole-rock chemistry alone nor the record of the mineral phases crystallizing subsequent to clinopyroxene can provide insights on such early magmatic processes. The obtained clinopyroxene archive can be used as a template for interpretation of the record preserved in the clinopyroxene cargoes of basalt to andesite lavas elsewhere, giving insights into the magma dynamics of the feeding plumbing system that are lost when using whole-rock chemistry.
42
Baker, Leslie L., and Malcolm J. Rutherford. "Crystallisation of anhydrite-bearing magmas." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 87, no. 1-2 (1996): 243–50. http://dx.doi.org/10.1017/s0263593300006659.
Full textAbstract:
ABSTRACT:Anhydrite has been identified as a phenocrystic phase in some silicic volcanic magmas, but it is not commonly described in plutonic rocks. Anhydrite-bearing magmas tend to form in arc environments and to contain hydrous, low-temperature, oxidised mineral assemblages. Phenocrystic anhydrite coexists with sulphur-enriched apatite and sometimes with pyrrhotite, in silicate melt that contains from 50 ppm to 1 wt% S, depending on temperature and conditions. Vapour coexisting with anhydrite- and water-saturated magma may contain from a few tenths of a mole per cent to a few mole per cent sulphur gases (SO2 and H2S), with the exact composition and gas speciation depending on temperature and oxygen fugacity. Samples of one anhydrite-bearing magma, the 1991 Pinatubo dacite, have been experimentally crystallised to determine whether the magma retains its characteristic sulphur-rich mineral phases during solidification. Results show that anhydrite and sulphur-rich apatite are retained throughout crystallisation and vapour phase evolution. This suggests that anhydrite-bearing intrusive equivalents of the Pinatubo dacite should be present in arc plutonic complexes.
43
GAFFNEY, AMY M. "Environments of Crystallization and Compositional Diversity of Mauna Loa Xenoliths." Journal of Petrology 43, no. 6 (June 1, 2002): 963–81. http://dx.doi.org/10.1093/petrology/43.6.963.
Full textAbstract:
Abstract Two picrite flows from the SW rift zone of Mauna Loa contain xenoliths of dunite, harzburgite, lherzolite, plagioclase-bearing lherzolite and harzburgite, troctolite, gabbro, olivine gabbro, and gabbronorite. Textures and olivine compositions preclude a mantle source for the xenoliths, and rare earth element concentrations of xenoliths and clinopyroxene indicate that the xenolith source is not old oceanic crust, but rather a Hawaiian, tholeiitic-stage magma. Pyroxene compositions, phase assemblages and textural relationships in xenoliths indicate at least two different crystallization sequences. Calculations using the pMELTS algorithm show that the two sequences result from crystallization of primitive Mauna Loa magmas at 6 kbar and 2 kbar. Independent calculations of olivine Ni–Fo compositional variability in the plagioclase-bearing xenoliths over these crystallization sequences are consistent with observed olivine compositional variability. Two parents of similar bulk composition, but which vary in Ni content, are necessary to explain the olivine compositional variability in the dunite and plagioclase-free peridotitic xenoliths. Xenoliths probably crystallized in a small magma storage area beneath the rift zone, rather than the large sub-caldera magma reservoir. Primitive, picritic magmas are introduced to isolated rift zone storage areas during periods of high magma flux. Subsequent eruptions reoccupy these areas, and entrain and transport xenoliths to the surface.
44
Lin, Selena Y., Yue Luo, Matthew M. Marshall, Barbara J. Johnson, Sung R. Park, Zhili Wang, and Ying-Hsiu Su. "A New Method for Improving Extraction Efficiency and Purity of Urine and Plasma Cell-Free DNA." Diagnostics 11, no. 4 (April 3, 2021): 650. http://dx.doi.org/10.3390/diagnostics11040650.
Full textAbstract:
This study assessed three commercially available cell-free DNA (cfDNA) extraction kits and the impact of a PEG-based DNA cleanup procedure (DNApure) on cfDNA quality and yield. Six normal donor urine and plasma samples and specimens from four pregnant (PG) women carrying male fetuses underwent extractions with the JBS cfDNA extraction kit (kit J), MagMAX Cell-Free DNA Extraction kit (kit M), and QIAamp Circulating Nucleic Acid Kit (kit Q). Recovery of a PCR product spike-in, endogenous TP53, and Y-chromosome DNA was used to assess kit performance. Nucleosomal-sized DNA profiles varied among the kits, with prominent multi-nucleosomal-sized peaks present in urine and plasma DNA isolated by kits J and M only. Kit J recovered significantly more spike-in DNA than did kits M or Q (p < 0.001) from urine, and similar amounts from plasma (p = 0.12). Applying DNApure to kit M- and Q-isolated DNA significantly improved the amplification efficiency of spike-in DNA from urine (p < 0.001) and plasma (p ≤ 0.013). Furthermore, kit J isolated significantly more Y-chromosome DNA from PG urine compared to kit Q (p = 0.05). We demonstrate that DNApure can provide an efficient means of improving the yield and purity of cfDNA and minimize the effects of pre-analytical biospecimen variability on liquid biopsy assay performance.
45
Barnes, Sarah-Jane, M. L. Zientek, and M. J. Severson. "Ni, Cu, Au, and platinum-group element contents of sulphides associated with intraplate magmatism: a synthesis." Canadian Journal of Earth Sciences 34, no. 4 (April 1, 1997): 337–51. http://dx.doi.org/10.1139/e17-030.
Full textAbstract:
The tectonic setting of intraplate magmas, typically a plume intersecting a rift, is ideal for the development of Ni – Cu – platinum-group element-bearing sulphides. The plume transports metal-rich magmas close to the mantle–crust boundary. The interaction of the rift and plume permits rapid transport of the magma into the crust, thus ensuring that no sulphides are lost from the magma en route to the crust. The rift may contain sediments which could provide the sulphur necessary to bring about sulphide saturation in the magmas. The plume provides large volumes of mafic magma; thus any sulphides that form can collect metals from a large volume of magma and consequently the sulphides will be metal rich. The large volume of magma provides sufficient heat to release large quantities of S from the crust, thus providing sufficient S to form a large sulphide deposit. The composition of the sulphides varies on a number of scales: (i) there is a variation between geographic areas, in which sulphides from the Noril'sk–Talnakh area are the richest in metals and those from the Muskox intrusion are poorest in metals; (ii) there is a variation between textural types of sulphides, in which disseminated sulphides are generally richer in metals than the associated massive and matrix sulphides; and (iii) the massive and matrix sulphides show a much wider range of compositions than the disseminated sulphides, and on the basis of their Ni/Cu ratio the massive and matrix sulphides can be divided into Cu rich and Fe rich. The Cu-rich sulphides are also enriched in Pt, Pd, and Au; in contrast, the Fe-rich sulphides are enriched in Fe, Os, Ir, Ru, and Rh. Nickel concentrations are similar in both. Differences in the composition between the sulphides from different areas may be attributed to a combination of differences in composition of the silicate magma from which the sulphides segregated and differences in the ratio of silicate to sulphide liquid (R factors). The higher metal content of the disseminated sulphides relative to the massive and matrix sulphides may be due to the fact that the disseminated sulphides equilibrated with a larger volume of magma than massive and matrix sulphides. The difference in composition between the Cu- and Fe-rich sulphides may be the result of the fractional crystallization of monosulphide solid solution from a sulphide liquid, with the Cu-rich sulphides representing the liquid and the Fe-rich sulphides representing the cumulate.
46
Francis, P. W., R. S. J. Sparks, C. J. Hawkesworth, R. S. Thorpe, D. M. Pyle, S. R. Tait, M. S. Mantovani, and F. McDermott. "Petrology and geochemistry of volcanic rocks of the Cerro Galan caldera, northwest Argentina." Geological Magazine 126, no. 5 (September 1989): 515–47. http://dx.doi.org/10.1017/s0016756800022834.
Full textAbstract:
AbstractAt least 2000 km3 of relatively uniform dacitic magma have been erupted from the Cerro Galan caldera complex, northwest Argentina. Between 7 and 4 Ma ago several composite volcanoes predominantly of dacitic lava were constructed, and several large high-K dacitic ignimbrites were erupted. 2.2 Ma ago the > 1000km3 Cerro Galan ignimbrite was erupted. The predominant mineral assemblage in the ignimbrites is plagioclase-biotite-quartz-magnetite-ilmenite; the Cerro Galan ignimbrite also contains sanidine. Fe-Ti oxide minerals in the Cerro Galan ignimbrite imply temperatures of 801–816 °C. Plagioclase phenocrysts in the ignimbrites typically have rather homogeneous cores surrounded by complex, often oscillatory zoned, rims. Core compositions show a marked bimodality, with one population consisting of calcic cores surrounded by normally zoned rims, and a second of sodic cores surrounded by reversely zoned rims. The older ignimbrites do not show systematic compositional zonation, but the Cerro Galan ignimbrite exhibits small variations in major elements (66–69% SiO2) and significant variations in Rb, Sr, Ba, Th and other trace elements, consistent with derivation from a weakly zoned magma chamber, in which limited fractional crystallization occurred. The ignimbrites have 87Sr/86Sr = 0.7108–0.7181; 143Nd/144Nd = 0.51215–0.51225, and δ18O = + 10 to + 12.5, consistent with a significant component of relatively non-radiogenic crust with high Rb/Sr and enriched in incompatible elements. Nd model ages for the source region are about 1.24 Ga. 87Sr/86Sr measurements of separated plagioclases indicate that Anrich cores have slightly lower 87Sr/86Sr than less calcic plagioclases, suggesting a small degree of isotopic heterogeniety in different components within the magmas. Pb isotope data for plagioclase show restricted ranges (206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb = 18.87–18.92, 15.65–15.69 and 39.06–39.16 respectively), and suggest derivation from Proterozoic crustal material(> 1.5 Ga).Contemporaneous satellite scoria cones and lavas are high-K basalts, basaltic andesites and andesites with SiO2 = 51–57%; K2O = 2–3% and normative plagioclase compositions of An37–48, and may be derived from a mantle source containing both ‘subduction zone’ and ‘within plate’ components. 87Sr/86Sr ranges from 0.7055 to 0.7094 and 143Nd/144Nd from 0.51250 to 0.51290. Variation diagrams such as MgO: SiO2 show two trends, one indicating closed system fractional crystallization and the other crustal contamination. AFC modelling of the open system rocks indicates a parental mantle-derived mafic magma which is itself enriched in K, Rb, Ba, U, Ta/Sm, Ta/Th and Sr, and has 87Sr/86Sr = 0.705–0.706, while the contaminant need not be more radiogenic than the dacitic ignimbrites.The Cerro Galan dacitic magmas are interpreted in terms of a deep and uniform region of the central Andean continental crust repeatedly melted by emplacement of incompatible-element-enriched, mantle-derived mafic magmas, a proportion of which may also have mixed with the dacite magmas. A component of the crustal material had a Proterozoic age. The magmas derived by crustal melting were also enriched in incompatible elements either by crystal/liquid fractionation processes, or by metasomatism of their source regions just prior to magma generation. Much of the crystallization took place in the source region during the melting process or in mid-crustal magma chambers. The magmas may have re-equilibrated at shallow levels prior to eruption, but only limited compositional zonation developed in high-level magma chambers.
47
Robin, Claude, and Alain Potrel. "Multi-stage magma mixing in the pre-caldera series of Fuego de Colima volcano." Geofísica Internacional 32, no. 4 (October 1, 1993): 605–15. http://dx.doi.org/10.22201/igeof.00167169p.1993.32.4.606.
Full textAbstract:
Datos geoquímicos y petrográficos acerca de las lavas anteriores de la caldera del Volcán de Fuego de Colima indican dos procesos magmáticos; cristalización fraccionada y mezcla de magma. Estos procesos pudieron suceder juntos, de tal manera que sus efectos se adicionan. Se distinguen tres tipos de mezcla: (i): mezcla entre nuevas inyecciones de magma profundo y minerales máficos acumulados en la parte inferior de la cámara magmática somera (ii): Mezcla, en la cámara, entre este magma juvenil (anteriormente diferenciado o no en una cámara más profunda, contaminando por olivino y clinopiroxeno o no) y un magma diferenciado de composición andesítica o dacítica. (iii) Mezcla por convección entre magmas ya diferenciados, por separación de minerales, o mezcla, o por ambos procesos, a diferentes niveles en la cámara somera.
48
Latypov, R. M., and S. Yu Chistyakova. "Origin of non-cotectic cumulates: A novel approach." Geology 48, no. 6 (March 27, 2020): 604–8. http://dx.doi.org/10.1130/g47082.1.
Full textAbstract:
Abstract Plutonic mafic complexes are composed of cumulates in which minerals mostly occur in cotectic proportions. This is consistent with a concept that basaltic magma chambers predominantly crystallize in situ from margins inward. However, cumulates with two (or more) minerals in proportions that are at odds with those expected from liquidus phase equilibria also locally occur in these complexes. Such non-cotectic cumulates are commonly attributed to either mechanical separation of minerals crystallizing from the same parental magma or mechanical mixing of minerals originating from different parental magmas. Here we introduce a novel concept that does not require any of these processes to produce non-cotectic cumulates. The model involves melts that start crystallizing upon their cooling, while ascending along feeder conduits from deep staging reservoirs toward the Earth’s surface. Depending on the degree of cooling, the melts become successively saturated in one, two, and more liquidus phases. Given that most crystals are kept in suspension, the resulting magmas would contain a cargo of equilibrium phenocrysts in notably non-cotectic proportions. The replenishment of basaltic chambers developing through in situ crystallization by such magmas is likely responsible for the occasional formation of non-cotectic cumulates in plutonic mafic complexes.
49
Wang, X., W. L. Griffin, S. Y. O’Reilly, X. M. Zhou, X. S. Xu, S. E. Jackson, and N. J. Pearson. "Morphology and geochemistry of zircons from late Mesozoic igneous complexes in coastal SE China: implications for petrogenesis." Mineralogical Magazine 66, no. 2 (April 2002): 235–51. http://dx.doi.org/10.1180/0026461026620025.
Full textAbstract:
AbstractThe Pingtan and Tonglu igneous complexes in SE China are typical of the calc-alkaline series developed at active continental margins. These two complexes are dominated by felsic rocks, temporally and spatially associated with minor mafic rocks. Morphological and trace-element studies of zircon populations in rocks from each of these complexes show that the zircon populations may be divided into 3–4 distinct growth stages, characterized by different distributions of morphological indices (Ipr, Ipy and Iel), and different contents of the substituting elements (Hf, U, Th, Y and P). The four growth stages recognized in the zircons are believed to have formed successively in the magma chamber, during the emplacement, and in the early and later stages of magma consolidation, respectively. All four stages are recognized in the plutonic Pingtan complex, whereas the stages 3 and 4 are less developed in the volcanic/subvolcanic Tonglu complex. Based on the chemistry and morphology of the different zircon populations of the Pingtan and Tonglu complexes, it is suggested that basaltic magmas underplating at the boundary between crust and mantle caused partial melting of the mid–lower crust and produced granitoid magmas. Subsequently, mixing between magmas was important.
50
MacDonald, R., B. Bagiński, B. G. J. Upton, H. Pinkerton, D. A. MacInnes, and J. C. MacGillivray. "The Mull Palaeogene dyke swarm: insights into the evolution of the Mull igneous centre and dyke-emplacement mechanisms." Mineralogical Magazine 74, no. 4 (August 2010): 601–22. http://dx.doi.org/10.1180/minmag.2010.074.4.601.
Full textAbstract:
AbstractGeochemical data are presented for five large Palaeogene dykes, members of the Mull swarm in southern Scotland and northern England (the Moneyacres, Hawick-Acklington, Barrmill, Muirkirk- Hartfell and Dalraith-Linburn dykes). The rock types range from basalt through andesite to dacite, although the range in individual intrusions is more restricted. The dykes are divisible into two groups; those where the compositional variation was generated by fractional crystallization of basaltic magmas, and those where it resulted from variable degrees of mixing of basaltic and silicic magmas. Several dykes are composite; the marginal facies can be more or less evolved than the central facies. The dyke magmas are thought to have originated from stratified magma chambers beneath the Mull centre and models are presented to show how the different components were derived from the chambers. Some dykes appear to have been terminated at or near the Southern Upland Fault, perhaps as a result of the chilling of early magma pulses by water in the fault. The Palaeogene dyke swarm is considerably more complex than previously recognized and has a significant input to models of the evolution of the Mull magmatic system.