Dissertations / Theses: 'Zircon trace element geochemistry'

1

Alberts, Rebecca C. "Petrogenesis of Plagiogranite and Granitoid in the Oman Ophiolite: A Comparative StudyUsing Oxygen Isotopes and Trace Elements in Zircon." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1479230993411029.

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Roell, Jennifer L. "Geochemical evidence for incremental emplacement of Palms pluton, southern California." Thesis, Connect to resource online, 2009. http://hdl.handle.net/1805/2061.

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Thesis (M.S.)--Indiana University, 2009.
Title from screen (viewed on February 2, 2010). Department of Earth Sciences, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Andrew P. Barth, Gabriel M. Filippelli, Kathy Licht. Includes vitae. Includes bibliographical references (leaves 102-110).

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Thomas, Christine L. "Hafnium Isotope Geochemistry of the Gabbroic Crust Sampled Along the Mid-Atlantic Ridge: Constraints on the Nature of the Upper Mantle." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1366731477.

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4

Dalpé, Claude. "Trace element partitioning between amphibole and basaltic melt." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34939.

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The effects of composition, pressure and oxygen fugacity on partition coefficients between amphibole and hydrous basaltic melt were studied at 1.5 to 2.5 GPa and 1000 to 1130°C. Partition coefficients (D i = concentration of element i in amphibole/concentration of i in melt) of large-ion-lithophile elements (LILE: Rb, Sr, Ba), high-field-strength elements (HFSE: Y, Zr, Nb, Ta, Hf), and rare-earth elements (REE: La to Lu) were determined between amphiboles and coexisting quenched melts created by partial crystallization of seven different starting compositions in a piston-cylinder high-pressure apparatus. Trace elements were analyzed by laser-ablation, microprobe inductively coupled plasma-mass spectrometer (LAM-ICP-MS). The effects of premium, temperature and oxygen fugacity on the partition coefficients are minor, but statistically measurable. Amphibole composition affects partitioning of these trace elements by a maximum factor of 3.5 in the range of pressures and temperatures studied with an oxygen fugacity range of 2 orders of magnitude above and below nickel-nickel oxide buffer. Experiments specifically investigating the role of Ti demonstrate that a positive correlation exists between amphibole VITi 4+ content and DBa, D Sr, DTa, D Zr, DLa, DCe, DPr, and DNd. Increasing pressure from 1.5 GPa, to 2.2 or 2.5 GPa (depending upon composition) increases DLILE, but decreases DHFSE and DREE. Raising the oxygen fugacity at 1.5 or 2.5 GPa by 3 orders of magnitude increases DRb, DBa, DLa, and D Nd, whereas DTi, D Hf, and DZr decrease; however, the maximum difference between partition coefficients measured at low and high oxygen fugacities is only a factor of 1.7. All of the effects of composition, pressure, and oxygen fugacity reflect the control of crystal chemistry on the partitioning of trace elements between amphibole and basaltic melt. No effects of melt composition were discerned in this study. The measured partition coefficients were used to investigate tr

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Hibbard, Shannon Maria. "Trace Element Geochemistry of Compositionally Layered Impact Spherules." Master's thesis, Temple University Libraries, 2017. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/460665.

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Geology
M.S.
Impact spherules are sand-sized spherical particles that have been interpreted to have formed by the cooling, crystallization, and quenching of melt droplets condensed from vapor plumes that are created during large meteor impacts. Spherules may be deposited globally as unique marker beds, such as at the K-Pg boundary. A minimum of 11 spherule beds have been identified in the Archean and Paleoproterozoic, and provide a record of impact events that predate any known craters. This study of 3.24 Ga impact spherules from the S3 spherule layer in the Barberton Greenstone Belt (BGB) in the Kaapvaal Craton of South Africa focuses on the heterogeneity of textures and geochemistry produced during the cooling and crystallization of spherules within a vapor plume. Type 4b spherules are layered phyllosilicate spherules with discrete differences in texture and composition between the inner and outer layer, even after alteration. Compositionally layered phyllosilicate spherules were analyzed using Energy Dispersive X-ray Spectroscopy (EDS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) to measure major, trace, and rare earth element (REE) concentrations. Backscatter Electron (BSE) images and elemental X-ray maps indicate a range of compositional differences between the inner and outer layers of type 4b spherules. The majority of REE plots have nearly flat patterns, with little to no light to heavy REE fractionation; however, the outer layers consistently have higher concentrations, averaging about 10x chondritic, whereas the interiors are at or below chondritic levels with a mid-REE enrichment. The trace and REE patterns of the type 4b spherules are consistent with a more mafic inner layer and a more intermediate outer layer. Mechanisms to produce this layered texture may include: (1) accretion of less mafic material from the plume onto existing melt droplets as the plume continues to fractionate, (2) collision of melt droplets of different viscosities, (3) by differentiation within the melt droplet prior to crystallization, or (4) by diagenetic effects. Based on textures, such as distinct boundaries between layers, and compositional patterns, such as an enrichment of Ti and REE in the outer layer, the data best fits the particle collision formation mechanism hypothesis, which has important implications for impact plume studies, such as plume density, turbulence, temperature, and opacity.
Temple University--Theses

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Gordon, Christopher Paul. "Major, minor and trace element geochemistry of Taiwan bedrock /." Connect to resource, 2006. http://hdl.handle.net/1811/21998.

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7

Nelson, James Baird 1967. "Analysis of trace element distributions distal to porphyry copper deposits." Thesis, The University of Arizona, 1996. http://hdl.handle.net/10150/278566.

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Enrichment and depletion of trace elements occurs in host rocks distal to porphyry copper deposits as a result of hydrothermal metasomatism. Subtle geochemical distributions in weakly propylitized host rocks is sufficient to indicate proximity to a mineralized system and may be applied to porphyry copper exploration. Samples collected adjacent to four porphyry copper deposits were analyzed for a multi-element suite, then normalized to the elemental concentrations of the fresh host rocks. The probability that an element has been enriched or depleted is determined by using concentrations in the unaltered host in conjunction with a calculated standard deviation. The probabilities have distinct zoning that is related to alteration around the deposits. Contribution lateral to deposits was observed with: Ag, As, Au, Bi, Br, Ca, Cu, Hg, Mn, Mo, Pb, Sb, Se, V, and Zn. Proximal to the mineralized portion of the systems elemental removal was observed with: Ba, Br, Ca, Mg, Mn, P, Pb, Ti, V, Y, and Zn.

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Jian, Han. "AN EXPERIMENTAL INVESTIGATION OF TRACE ELEMENT PARTITIONING DURING CORE CRYSTALLIZATION." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459182154.

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9

Bond, Brian Robert 1958. "Selective trace element geochemistry, San Antonio Mine, Santa Eulalia, Chihuahua." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/558066.

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Bouch, Jonathan E. E. "Trace element geochemistry of authigenic heavy minerals in reservoir sandstones." Thesis, University of Aberdeen, 1996. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU089767.

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Authigenic growths of heavy minerals, crystallised under relatively low temperature diagenetic conditions have been recognised in a number of sedimentary sequence. A range of microbeam techniques have revealed trace element geochemical variations on several scales in authigenic titanites and apatites. These variations occur, within individual cement grains and patches, within a single sedimentary sequence, and between different sedimentary sequences. Mixed fluvial-aeolian, Permian, sediments at the Cock of Arran (Isle of Arran, Scotland) contain pore filling titanite cements. The titanites show a range of zoning patterns, dominated by compositional sector zones. The sector zones are defined by large (order of magnitude) differences in rare earth element (REE) and high field strength element (HFSE) concentrations between titanite grown at different crystal faces. The mechanism responsible for sector zone formation is considered to relate to differences in the surface structure of titanite at different crystal faces. Faces of the forms { 100 } and { 001 } are likely to have surface configurations more amenable for impurity element incorporation than faces of the form { 161 }. This evidence for disequlibirium titanite growth, and the large differences which must exist between effective partition coefficients at different titanite crystal faces, makes models of equilibrium trace element partitioning effectively meaningless. Minor growth zones are also present and relate to subtle differences in the REE composition of the titanite. These variations have been used to construct a model of titanite-fluid REE partitioning which suggests that the HREE have higher effective titanite-fluid partition coefficients than the LREE. In the continental Statfjord Formation (Jurassic, North Viking Graben) authigenic apatite occurs as overgrowths on variably corroded detrital cores. The authigenic apatite is chemically very distinct from the detrital apatite and contains high concentrations of Sr, REE, F, and probable concentrations of C.

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11

Lightfoot, P. C. "Isotope and trace element geochemistry of the South Deccan lavas, India." Thesis, Open University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355991.

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12

Pegram, William Joseph. "The isotope, trace element, and major element geochemistry of the Mesozoic Appalachian tholeiite province." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/15104.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1986.
MICROFICHE COPY AVAILABLE IN ARCHIVES AND LINDGREN.
Bibliography: leaves 598-622.
by William Joseph Pegram.
Ph.D.

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13

Spitz, Anna Hargrave, and Anna Hargrave Spitz. "Trace element analysis of ureilite meteorites and implications for their petrogenesis." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185743.

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Ureilite meteorites are the second largest class of achondrite meteorites. They are perhaps the most enigmatic of all classes of meteorites and the dilemma over how they were formed has perplexed the meteoritic community for over a decade. This research was undertaken to illuminate the details of the petrogenesis of ureilites through the collection of trace element data. The results presented here indicate that many of the petrogenesis hypotheses promoted are no longer tenable and that the available data on ureilites are not sufficient to unravel the mystery of their origin. This dissertation discusses the data collected using two techniques: neutron activation analysis and inductively coupled plasma-mass spectrometry. Specific procedures required to study the ureilites (due to low concentrations of some trace elements) are delineated. Results are presented for the following elements: Ca, Co, Zn, Ga, Cu, Cs, Rb, Sr, Mo, Y, Ba, REE, Hf, W, Re and Ir. The results lead to the conclusion that the ureilites must be considered a mixture of materials--an original ultramafic rock formed by melting of processed source material combined with carbonaceous material added after the ultramafic formation. This conclusion explains the trace element chemical signatures and is supported by the age information obtained from Sm-Nd and Rb-Sr isotopic systems.

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14

Kay, Andrew. "Sm-Nd isotope, major element, and trace element geochemistry of the Nashoba terrane, eastern Massachusetts." Thesis, Boston College, 2012. http://hdl.handle.net/2345/bc-ir:107672.

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Thesis advisor: Christopher J. Hepburn
The Nashoba terrane in eastern Massachusetts comprises Cambrian-Ordovician mafic to felsic metavolcanic rocks and interlayered sediments metamorphosed during the mid-Paleozoic and intruded by a series of dioritic to granitic plutons during the Silurian to earliest Carboniferous. This work comprises two parts discussing the Sm-Nd isotope characteristics and major and trace element geochemistry of the Nashoba terrane: the first discusses the Cambrian-Ordovician metamorphosed units, the second discusses the Silurian-Carboniferous plutons. Part I: The Nashoba terrane in eastern Massachusetts lies between rocks of Ganderian affinity to the northwest and Avalonian affinity to the southeast. Its relationship to either domain was unclear and has been investigated. Major and trace element geochemical data indicate a mix of arc, MORB, and alkaline rift related signatures consistent with an origin of the terrane as a primitive volcanic arc-backarc complex built on thinned continental crust. Newly determined Sm-Nd isotopic data clarifies the original tectonic setting. Amphibolites of the Marlboro and Nashoba Formations have high εNd values (+4 to +7.5) consistent with formation in a primitive volcanic arc with minimal interaction between arc magmas and crust. Intermediate and felsic gneisses have moderate εNd values between +1.2 and –0.75 indicating a mixture of juvenile arc magmas and an evolved (likely basement) source. Depleted mantle model ages of 1.2 to 1.6 Ga indicate a Mesoproterozoic or older age for this source. Metasedimentary rocks have negative εNd values between –6 and –8.3 indicating derivation primarily from an isotopically evolved source (or sources). The model ages of these metasedimentary rocks (1.6 to 1.8 Ga) indicate a source area of Paleoproterozoic or older age. The εNd values and model ages of the intermediate and felsic rocks and metasedimentary rocks indicates that the basement to the Nashoba terrane is Ganderian rather than Avalonian. The Nashoba terrane therefore represents a southward continuation of Ganderian arc-backarc activity as typified by the Penobscot and/or Popelogan-Victoria arc systems and the Tetagouche-Exploits backarc basin in the northern Appalachians. Part II: Between 430 and 350 Ma the Nashoba terrane experienced episodic dioritic and granitic plutonism. Previous workers have suggested a supra-subduction zone setting for this magmatism based on the calc-alkaline nature of the diorites. Previously determined major and trace element geochemical data along with newly determined Sm-Nd isotopic data indicate that a subduction zone was active beneath the Nashoba terrane during the majority of the 430 to ca. 350 Ma magmatism (and likely throughout). Trace element geochemistry indicates a strong arc component in all magmas and suggests that the various Silurian to Carboniferous plutonic rocks of the Nashoba terrane could all have been derived by modification of a slightly enriched NMORB-type source via subduction zone input and crustal contamination. Most of the rocks from this period have intermediate εNd values consistent with contamination of juvenile magmas by an evolved source. The late Proterozoic model ages for most of these rocks suggest the Ganderian basement of the Nashoba terrane as the source of evolved material. One rhyolite from the nearby Newbury Volcanic Complex (of unknown affinity) has a moderately negative εNd value consistent with derivation by partial melting of Cambrian-Ordovician metasedimentary rocks of the Nashoba terrane. This suggests that the Newbury Volcanic Complex formed as the surface expression of mid-Paleozoic Nashoba terrane plutonism. Geochemical and isotopic similarities between the plutonic rocks of the Nashoba terrane and widespread contemporary Ganderian plutonism suggest that the Nashoba terrane remained a part of Ganderia during its transit and accretion to the Laurentian margin. Significantly younger model ages in the youngest granitic rocks indicate that Avalonian crust may have underthrust the Nashoba terrane after 400 Ma and contributed to the generation of these granites
Thesis (MS) — Boston College, 2012
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Earth and Environmental Sciences

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15

Jones, Bryn. "Relationships between organic maturity and inorganic geochemistry in Upper Jurassic petroleum source rocks from the Norwegian North Sea and the United Kingdom." Thesis, University of Newcastle Upon Tyne, 1991. http://hdl.handle.net/10443/679.

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The aim of this study was to. examine the relationship between organic maturity and trace element geochemistry of organic rich mudstones, to assess their behaviour as sources or sinks of metals during diagenesis, and their role in mineral deposit genesis. The suite studied consisted of 193 samples from the Draupne, Heather, and Kimmeridge Clay Formations from the Norwegian North Sea and onshore UK. All three formations had above average contents of C and S, and the Draupne and Heather Formations had a low carbonate content. The Draupne Formation was particularly enriched in a number of trace elements but only Cr, Mo, Nb, and U were enriched in all three formations. After transformation of the data to avoid difficulties in interpretation, correlation analysis allowed the trace elements to be divided into three groups on the basis of their mineralogical residences. The use of a battery of geochemical and mineralogical indices demonstrated that variation in sedimentological and environmental factors were significant within the formations studied, and that the relationship between organic maturity and trace element content could not be investigated in isolation. The technique of path analysis was used to assess the strength and nature of this relationship relative to the variation due to other causes. Pb and Zn were found to increase with increasing maturity in both the Draupne and Heather Formations, and Mo was found to decrease. U was seen to decrease, and Cd to increase, in the Draupne Formation only, where they were especially abundant. It is believed that Pb and Zn were supplied by migrating basinal brines which may have acted to remove Mo and U. Other processes which may have mobilised these elements are the in situ generation of organic acids and hydrocarbons.

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Sarkar, Chiranjeeb. "Trace element and isotope geochemistry of perovskites from kimberlites of Southern Africa." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.544325.

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17

Jones, Christina. "Trace element fingerprinting in the Gulf of Mexico volcanic ash." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/863.

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18

Thomas, Jay Bradley. "Melt Inclusion Geochemistry." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/11262.

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Silicate melt inclusions (MI) are small samples of melt that are trapped during crystal growth at magmatic pressures and temperatures. The MI represent a sample of the melt that was isolated from the magma during host crystal growth. Thus, MI provide a valuable tool for constraining the magmatic history of igneous systems because they provide an unambiguous method to directly determine compositions of melts from which the host crystal grew. As such, coupled petrographic examination and geochemical analyses of MI and host crystals can reveal information about crystal/melt processes in igneous systems that are difficult (or impossible) to assess through conventional methods. Many studies have used MI to monitor large scale petrogenetic processes such as partial melting and fractional crystallization. The research presented below focuses on using MI to constrain processes that operate at the crystal/melt interface because MI are samples of melt that resided adjacent to the host crystal prior to entrapment as an inclusion. Chapter one addresses challenges associated with preparing small crystals containing MI for geochemical analysis. In chapter two trace element analyses of MI and the immediately adjacent host zircon crystals are used to determine zircon/melt partition coefficients. In chapter 3 the significance of boundary layer development adjacent to growing crystals is evaluated by comparing the trace element compositions of MI host crystals that have significantly different trace element mineral/melt partitioning behavior.
Ph. D.

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19

Peshkepia, Ardian. "Trace element geochemistry of andesites associated with massive sulfide deposits in Noranda, Quebec." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0021/MQ49755.pdf.

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20

Jamieson, Robert Andrew. "Trace element geochemistry of Belizean and Bermudan stalagmites : new tools, proxies and applications." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12055/.

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Speleothem trace elements are an important and effective tool for palaeoenvironmental reconstruction. They can be used to reconstruct a plethora of climate variables, and are a vital tool for improving our understanding of the climate system. This is particularly important given the on-going challenges of comprehending and tackling anthropogenic climate change. Only by thoroughly understanding controls on climate variability can we attempt to predict future change. This thesis presents a broad study of current speleothem trace element proxies. In addition to reviewing the current state of knowledge, this thesis presents several additions and developments to the speleothem trace element toolkit. The 22 year ATM-7 trace element record from Belize has a greater than seasonal resolution, and a highly precise chronology. As a result of this exceptional chronology, combined with extremely high resolution LA-ICP-MS analysis, it is possible to detect the geochemical indicators of volcanic ash deposition. Principal Component Analysis identifies a clear signal of a multi-elemental input of trace elements at the beginning of the wet season following volcanic eruptions with ash reaching the cave site. U/Ca variability in aragonitic speleothems is strongly influenced by the occurrence of Prior Aragonite Precipitation. The U/Ca record in Belizean stalagmite YOK-G strongly suggests that modern drying has occurred in Belize, primarily caused by a reduction in wet season rainfall. This is consistent with published stable isotope data from YOK-G, previously interpreted as the result of southward ITCZ displacement. These results strongly suggest that U/Ca values in aragonitic speleothems are excellent proxies for rainfall variability. This new tool, combined with the exceptional chronological control characteristic of aragonitic stalagmites and the high spatial resolution afforded by modern microanalytical techniques, should facilitate the construction of new exquisitely resolved rainfall records, providing rare insights into seasonality changes as well as long-term changes in local recharge conditions. In the Bermudan stalagmite BER-SWI-13, magnesium concentrations record, via varying prior calcite precipitation, changes in local rainfall which appear to correspond to variation in the North Atlantic Oscillation (NAO). Through a different mechanism, phosphorous also correlates with changes in the NAO. We infer that local effective rainfall changes, influenced by NAO state, influence bioproductivity above the cave and thus the amount of phosphorous in dripwaters. Surprisingly, for a location such as Bermuda, we see no evidence of clear direct anthropogenic influence on speleothem chemistry. These results V suggest that Bermudan speleothems are well situated to record basin scale climate changes in the North Atlantic. Together, these three separate studies demonstrate the strength and versatility of high- resolution trace element analysis of speleothems. They establish new techniques of data analysis, new proxies, and the applications of existing proxies in new contexts to reconstruct palaeoenvironmental variables. Looking forward, these discoveries demonstrate that speleothem trace elements continue to have a great deal to offer to the field of palaeoclimate reconstruction, and that there are still new techniques and applications to be developed.

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McHugh, Kelly C. "APPLICATIONS OF TRACE ELEMENT AND ISOTOPE GEOCHEMISTRY TO IGNEOUS PETROLOGY AND ENVIRONMENTAL FORENSICS." Miami University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=miami1494441686890672.

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22

Van, Achterbergh Esmé. "The development of the national accelerator centre proton microprobe as an analytical tool in geochemistry." Master's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/22046.

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Bibliography: pages 94-99.
This thesis describes work performed to establish and demonstrate a quantitative trace element microanalysis technique for geological material using protons accelerated by the Van de Graaff Accelerator at the National Accelerator Centre (NAC) in Faure near Cape Town. The method relies on the analysis of Proton Induced X-ray Emission (PIXE) spectra, interpreted with the help of the GeoPIXE software package. The use of the Si(Li) energy dispersive detector provides simultaneous multi-element detection at the parts-per-million (ppm) level, and a scanning beam facility permits trace element distributions to be studied at these levels. The calibration of the detector efficiency and the thicknesses of selectable X-ray attenuating filters was performed using pure elemental samples. This involved the accurate determination of the target to detector distance, the thickness of the active volume of the Si(Li) detector crystal, the thicknesses of all the absorbing layers between the sample and the detector crystal, and the assessment of the effects of incomplete charge collection in the detector.

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Wilkinson, Darren James. "Geochemistry of eclogites from Western Norway : implications from high-precision whole-rock and rutile analyses." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/10531.

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The Western Gneiss Region (WGR) in Norway is home to some of the world’s most spectacular exposures of high pressure (HP) and ultrahigh pressure (UHP) eclogites. Despite extensive petrological studies into their pressure, temperature and time (PTt) histories, relatively few have reported on their trace element compositions. Such data can be used to supplement our understanding of the provenance and history of Norwegian eclogites, as well as to further our understanding of trace element fluxes during HP to UHP metamorphism in subduction zone settings. In order to address this shortfall in data availability, the first step was to investigate and apply the best dissolution techniques for preparing eclogite samples for chemical analysis. Eclogites commonly contain up to a few weight percent rutile (TiO2), which is known to be an important host for a variety of major and trace elements (e.g. Ti, Nb and Ta). However, typical rock digestion procedures are incapable of dissolving rutile, and thus may lead to inaccurate measurements. It was found that that total dissolution of rutile can be achieved by dissolving samples in sealed pressure vessels at increased pressures and temperatures, ultimately leading to greatly increased data accuracy for analyses of any rutile-bearing lithology. The solutions were analysed by standard ICP-MS techniques and the results compared to analyses of powders by XRF spectrometry. Our high-accuracy and high-precision data were subjected to immobile trace element discriminant analyses that suggested eclogites belonged to three broad geochemical groups: eclogites with mid ocean ridge Basalt (MORB)-like composition; eclogites with arc-like composition; and eclogites with geochemical signatures significantly perturbed by metamorphism. The geochemistry of eclogites in the first two groups are shown to likely reflect protolith composition, and as such we used model protolith compositions to calculate estimated element mobilities (EMMs) for those elements considered relatively mobile during metamorphism. It was not possible to determine protoliths for eclogites in the third category using trace elements alone. Finally, the trace element geochemistry of a large number of separated eclogite-hosted rutiles was studied. The data collected were used to demonstrate that rutile contains significant amounts of the whole-rock’s high field strength element (HFSE) budget, and may exert significant control on the HFSE composition of passing hydrothermal fluids. Furthermore, Zr-in-rutile thermometry (ZRT) was applied to separated rutiles. This temperature information was used to better our understanding of the thermal history of the WGR, as well as to create a map of eclogite temperatures in the Nordfjord-Statlandet area. This high-resolution thermal map of arguably the most important area of the WGR, supports current interpretations that during the Caledonian Orogeny the leading edge of the Baltica plate was consumed in a northwest to north-northwest-dipping subduction zone under Laurentia. Furthermore, isotherms on this map mimic several major fold hinges in the region rather well, thus providing support to the hypothesis that such structures were most likely formed during the collapse of the Scandinavian Caledonian Orogen after the peak metamorphism of most eclogites.

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Thomas, Louise Elana. "Uranium series, major and trace element geochemistry of lavas from Tenerife and Lanzarote, Canary Islands." Thesis, Open University, 1999. http://oro.open.ac.uk/58003/.

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Ocean Islands Basalts provide important windows into the compositional variations of the Earth's mantle, which in tum constrains models for mantle convection and evolution. The Canary Islands show contrasting styles of eruption and evolution of magmas in an ocean island setting. U-Th-Ra disequilibrium have been used to constrain rates and timescales of melt generation and differentiation beneath ocean islands, and to estimate the buoyancy flux, potential mantle temperature and the depth and degree of melting. The Canary Islands provide a rare opportunity to observe U-Th-Ra disequilibrium, because they are underlain by a region of low buoyancy flux, and were expected to show significant disequilibrium. Tenerife is underlain by numerous magma chambers, in which magmas have time to differentiate from basanites to phonolites, erupting to form large strato-volcano complexes. The fissure and small vent eruptions of unusually primitive basanites and alkali basalts from Lanzarote show little evidence of magma chambers, unless of substantial size and longevity at depth. The U-Th results indicate that lavas underwent rapid transport from the melt region. The historic and recent pre-historic eruptions (1824, 1730-36, Corona) from Lanzarote have some of the most primitive compositions found on oceanic islands with low SiO² contents (< 51 %), Mg numbers of 67-74 and high Cr and Ni contents. The rocks are restricted in Sr, Nd and Pb isotopes, being displaced from MORB towards the HIMU om field. The major and trace elements have been modelled by mixing a deep smaller degree (1 %) melt and a shallower larger degree (4%) melt. Negative K anomalies were observed in the small degree melts indicating that melt generation may have continued at a shallow level, perhaps to within the lithospheric mantle with melting in the presence of residual phlogopite. The Lanzarote source was modelled as a mixture of HIMU and EMIl asthenospheric mantle, with a small contribution from a shallow, lithospheric source. Thermal erosion of the lithospheric mantle is required for melting at depths (58 and 73 km) modelled from the major and trace elements. The Lanzarote lavas exhibit significant (²³⁰Th/²³⁸U) disequilibrium with ²³⁰Th excesses of 6 - 81 %. This was modelled by dynamic melting giving a calculated melt rate of 0.125 x 10^-3 kg.m^-1.yr^-1, a timescale of melt generation (matrix transfer time) of 270 ka for the 1 % melt and 1,100 ka for the 4 % melt. A consistent upwelling rate of I cm.yr^-1 and an assumption that the melting process has remained consistent over tens of km at depth. The Teide-Pico Viejo complex lavas have undergone fractionation and mixing to form compositions from basanite to phonolite. Crystallising phases differ in the Pico Viejo series, where amphibole is dominant in the more evolved lavas, and Pico Teide series, where olivine in the major control. The more evolved lavas require assimilation and fractional crystallisation to explain the range in ⁸⁷Sr/⁸⁶Sr. (²³⁰Th/²³⁸U) ranges from 1.004-1.39 and gives information regarding the timescales of differentiation within the magma chambers, not least because the youngest mafic rocks have the highest (²³⁰Th/²³⁸U) and the most evolved phonolites have the lowest. The timescale of differentiation from basanite to phonolite is of the order of 150,000 years, which links to the periodicity of the eruption cycles on the island. A Ra-Th 'pseudo' whole rock isochron gave an age of fractionation for the Montafia Blanca eruption of 2.3 ka ± 80, which is a maximum of 300 years prior to eruption, indicating that fractionation of plagioclase as a possible trigger of an eruption.

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25

Taylor, Arthur. "A trace element study of sediments from the Olifants River estuary, the Berg River estuary, and the off-shore Mud Belt." Master's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/9027.

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Includes bibliographical references (leaves 99-105).
Trace elements have received increased attention since the mid-1900's. Although some studies have investigated trace element accumulation as a result of urban expansion in the Western Cape, South Africa, few have catalogued the accumulation and behavior of trace elements resulting from agricultural practices. This study investigates the distribution and behavior of trace elements for the Olifants and Berg river catchments by focusing on the sediments of the estuaries. The dominant industry in both catchments is agriculture and there exists relatively little urban sprawl. Two sediment samples taken from the offshore mud belt in the vicinity of the two river mouths were also analyzed. The sediments were analyzed for trace elements using inductively coupled plasma mass spectrometry (ICP-MS), major elements using X-ray ﬂuorescent spectroscopy (XRF), total sulfur using XRF, total and organic carbon using a C:H:N analyzer, and grain size analysis was performed (>62 μm, 38-63 μm, 2-38 μm, <2μm). The mud belt cores were dated using 14C dating. Estuarine surface waters were analyzed for trace elements, pH, dissolved oxygen (DO), electrical conductivity (EC), and temperature. The trace elements arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) were focused on. The trace element concentrations in the sediments were compared with those of soils that occur in the study area, as well as their parent materials, to determine background concentrations. The concentration proﬁles of elements with respect to depth are compared with natural deposition rates to recognize signs of recent enrichment of individual trace elements. Inter-element comparisons are made in an attempt to determine speciation. Comparison between the estuarine and mud belt sediments were made to assess the estuaries ability to ﬁlter ﬂuvial trace elements, as well as to determine the sediment contributions of the Olifants and Berg rivers to the mud belt. Statistical analysis was performed to"group sediment populations Trace element and organic matter concentrations showed strong positive correlations with ﬁne-sized particles. The mud belt sediments displayed considerably more OC than the estuarine sediments. The trace elements appear to associate predominantly with clay minerals (alumino-silicates), Fe/Mn oxides, and organic matter. Trace element correlations with S and carbonate carbon were also observed. Comparison with estimates of natural deposition rates and compositions of soils occurring in the catchments did not suggest an anthropogenic pollution input. From the data available the estuarine and Mud Belt sediments appear enriched in Cd, Cu and Zn in comparison to the background soils. The estuaries seem to effectively trap Zn and Pb, but do not capture As well. Statistical analysis suggest that, of the rock types considered, the sediments of the Olifants and Berg river estuaries and those of the off shore mud belt are most similar to sediments derived from the Malmesbury and Ecca Groups. The Olifants and Berg rivers are important sources of water for the farming community, as well as for municipal use in the Western Cape. Based on this investigation of the estuarine waters and sediments the rivers appear to be in good health in regards to trace element concentrations.

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26

Caprile, Jose A. "The geochemical influence of trace element concentrations from marine sedimentary bedrock on freshwater streams in the western Transverse Mountain Ranges." Thesis, California State University, Long Beach, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10134003.

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Government agencies assess the biological integrity of streams and the chemistry of groundwater to monitor anthropogenic impacts on freshwater ecosystems. Some of the impacted streams lack obvious stressors that can be linked to the impacts. In the case of elevated nutrients and ionic concentrations found in impacted stream sites within the Malibu Creek Watershed, research from the Las Virgenes Municipal Water District pointed towards the naturally occurring leachate from the Modelo formation, which contests previous studies suggesting an influence from anthropogenic activity. Differentiating between natural sources of trace element concentrations and point/non-point source contamination could aid in resolving water quality issues since monitoring occurs near anthropogenic development. Water, bedrock, and diatoms were sampled from spring, seep, and stream sites underlain by Tertiary sedimentary bedrock throughout the study area. Multivariate analyses revealed an association of groups driven by salinity along with a correlation between geochemistry and diatom assemblages. Mixing models and radar charts identified potential rock types as sources for analyte concentrations. Sites that were underlain by the Modelo formation presented brackish water conditions and high nutrient concentrations, which potentially influenced the diatom species compositions found at the spring/seep sites as a result of weathering.

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27

Schmidberger, Stefanie. "Hf, Sr, Nd and Pb isotope systematics and major and trace element compositions of the Archean subcratonic lithosphere beneath Somerset Island, Arctic Canada." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37656.

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Hf, Sr, Nd and Pb isotopes, and major, trace and rare earth elements (REE) were determined for a suite of peridotite and pyroxenite xenoliths, constituent garnet and clinopyroxene and the host Nikos kimberlite (100 Ma) from Somerset Island, in order to constrain the chemical and isotopic composition of the lithosphere beneath the northern Canadian craton. The refractory Nikos peridotites are characterized by high olivine forsterite contents (avg. Fo = 92.3) and depletions in incompatible major elements (Fe, Al, Ca), but are enriched in incompatible trace elements, such as large ion lithophile elements (LILE) and light rare earth elements (LREE), while having approximately chondritic heavy rare earth element (HREE) contents. Mass balance calculations using REE contents of clinopyroxene and garnet indicate that calculated LREE abundances for the Nikos xenoliths are significantly lower (e.g. Nd ~50%) than those of the analyzed whole-rocks. These results suggest the presence of small amounts of a kimberlite-related LREE-rich interstitial component (i.e. ~1% kimberlite liquid and/or ~0.01% apatite) to account for the excess LREE abundances, with little effect on the HREE budgets of the xenoliths.
The 143Nd/144Nd(0.1Ga) (0.51249--0.51276) isotopic compositions of the Nikos peridotites are little variable and overlap those of the Nikos kimberlite at the time of sample transport. The low-temperature peridotites (<1100°C) that sample the shallow lithosphere are characterized by more radiogenic 176Hf/177Hf(0.1Ga) (0.28296--0.28419) and Pb (206Pb/204Pb (0.1Ga) = 17.82--19.03), but lower 87Sr/ 86Sr(0.1Ga) (0.7047--0.7066) isotopic ratios than those of the high-temperature peridotites (>1100°C; 0.28265--0.28333; 17.18--18.30; 0.7064--0.7085, respectively). Incompatible trace element compositions of the xenoliths confirm this depth stratification indicating that shallow and deep (>160 km) Somerset lithosphere are characterized by distinct chemical and isotopic characteristics.
The Lu-Hf isotope compositions of the low-temperature peridotites plot along a 2.8 Ga reference isochron, which is consistent with an interpretation that the shallow Somerset lithosphere stabilized in the Archean to depth of ~150 km. The deep lithospheric mantle, which is probably younger, does not share the same petrogenetic history and may contain recycled material (altered oceanic crust and sedimentary component?). The Hf isotope compositions for the shallow low-temperature peridotites indicate that part of the lithosphere beneath the Canadian craton is characterized by more radiogenic Hf isotope signatures than estimates for "depleted" mantle.

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Johnson, Kevin Todd Michael. "Trace element geochemistry of oceanic peridotites and silicate melt inclusions--implications for mantle melting and ocean ridge magmagenesis." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/54339.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, and Woods Hole Oceanographic Institution, 1990.
Vita.
Includes bibliographic references.
by Kevin Todd Michael Johnson.
Ph.D.

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29

O'Driscoll, Cynthia Marie. "The application of trace element geochemistry to determine the provenance of soapstone vessels from Dorset Palaeoeskimo sites in western Newfoundland /." Internet access available to MUN users only, 2003. http://collections.mun.ca/u?/theses,164162.

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30

Starkey, Natalie. "Evolution of the Earth's mantle-crust-atmosphere system from the trace element and isotope geochemistry of the plume-mantle reservoir." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/5934.

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The 62 million year old lava flows of Baffin Island and West Greenland represent the earliest phase of magmatism in the North Atlantic Igneous Province (NAIP). These picritic lavas are characterised by high magnesium contents owing to their high proportion of olivine crystals. The parental magmas for the picrites are likely to have accumulated olivine crystals on their transit through the lithosphere and crust. Debate over the origin of accumulated crystals in the lavas results in uncertainty in the temperature and composition of the parental magmas for the early NAIP. The magnesium-rich olivine crystals (up to Fo93) in the picrites of this study are shown not to have a xenocrystic origin. The samples, therefore, support the inference of high potential temperatures for the Baffin Island-West Greenland magmas, ~200oC above ambient mantle. The picrites of Baffin Island and West Greenland display the highest terrestrial magmatic 3He/4He (up to 50 Ra, where Ra is the atmospheric value 1.39 x 10-6), values that are considerably higher than the highest 3He/4He in contemporary ocean island basalts, which reach a maximum of ~30 Ra. High 3He/4He in Baffin Island and West Greenland are associated with a wide range of incompatible trace element and lithophile radiogenic isotopic compositions, not dissimilar to the range of compositions displayed by lavas at mid-ocean ridges, and overlapping the range displayed by most northern hemisphere ocean island basalts. Crustal contamination modelling in which high-grade Proterozoic crustal basement rocks are mixed with depleted parents cannot account for the compositional trends displayed by the picrites. Major and trace element compositions were determined on melt inclusions in high- 3He/4He picrites that span a wide range of whole-rock incompatible trace element and radiogenic isotopic compositions. The melt inclusions support the findings from the whole-rock study since melt inclusion compositions reflect the composition of their associated whole-rock, with no anomalous compositions present. In addition, there is no evidence for a contribution of a proportion of depleted melts to the source of the relatively enriched whole-rock samples. Therefore, since all melt inclusions were contained within high-3He/4He samples, it is shown that high 3He/4He is a feature of both depleted and relatively enriched melt compositions. The wide range in whole-rock compositions of the Baffin Island and West Greenland picrites represents that of the sub-lithospheric mantle source region and is inconsistent with derivation of the picrites from residues of ancient mantle depletion. The apparent decoupling of helium from trace elements and radiogenic isotopes is hard to reconcile with simple mixing of a high-helium concentration, high-3He/4He reservoir with various depleted and enriched helium-poor mantle reservoirs. It is possible that primordial helium has diffused into a reservoir with a composition similar to that of the convecting upper mantle. However, this must have occurred after the development of existing mantle heterogeneity. The high-3He/4He picrites require the existence of a deep, primordial helium-rich reservoir. Whether this reservoir is present in the upper or deep mantle, or even the core, remains uncertain.

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Cosky, Brian Wright. "Os-Sr-Nd-Pb ISOTOPIC AND TRACE ELEMENT STUDY OF MAGMATIC PROCESSES WITHIN THE SIERRA DEL CHICHINAUTZIN VOLCANIC FIELD, TRANS-MEXICAN VOLCANIC BELT." Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1291864089.

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32

Telfeyan, Katherine Christina. "Analysis of trace element cycling in marsh pore waters of the lower Mississippi River Delta with a case study of vanadium in groundwaters of Texas and Nevada." Thesis, Tulane University School of Science and Engineering, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10143983.

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This dissertation combines field and laboratory work to examine how delta hydrology and sedimentology affects trace element cycling in marsh porewaters. This work was prompted by our lack of understanding of the hydrogeochemistry in the lower Mississippi Delta and how biogeochemical reactions affect fluxes of groundwater constituents to the ocean. In particular, I measured the concentrations of a suite of redox-sensitive trace elements (Fe, Mn, V, As) to determine the dominant geochemical reactions operating in marsh aquifers.

Because much more is known about As, I first conducted a study comparing V geochemistry along flow paths in a reducing sand aquifer in Texas and an oxidizing bedrock aquifer in Nevada. In agreement with other studies, V concentrations are much higher under oxidizing alkaline conditions. Under the reducing, circumneutral conditions of the Carrizo Sand aquifer, V concentrations are low but relatively constant, owing to complexation with dissolved organic matter. Similar observations regarding V geochemistry are observed in marsh groundwaters. Specifically, in pore waters of organic-rich sediment experiencing sulfate-reducing conditions, V concentrations are high owing to V complexation with organic matter, whereas in coarser-grained sediments, V may be removed from solution by adsorption. Arsenic geochemistry in pore waters varies as a function of depth. In the shallow subsurface, As concentrations are high and stabilized in solution by formation of thioarsenates. At depth, As appears to be sequestered through coprecipitation with pyrite.

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33

Porter, Sarah Julie. "Nickel and osmium isotope and trace element geochemistry of organic-rich sedimentary rocks : the first investigation of Ni isotope systematics in marine sediments." Thesis, Durham University, 2012. http://etheses.dur.ac.uk/4427/.

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Understanding the chemical composition of organic-rich marine sediments has the potential to: 1) allow evaluation of variations in ocean chemistry, enabling assessment of changes in global processes throughout geological time; and 2) provide an increased temporal and spatial understanding of petroleum systems. Herein two geologically distinct organic-rich sedimentary formations are explored utilising trace elements, and rhenium-osmium (Re-Os) and nickel (Ni) isotope systematics. Additionally, this thesis is the first study to investigate the behaviour of Ni isotope systematics in organic-rich marine sediments. Osmium isotope profiling across the Sinemurian-Pliensbachian boundary GSSP indicates that there was a significant contribution of unradiogenic Os to the oceans at this time. Seawater 187Os/188Os(i) values range from ~0.20 – 0.48, becoming increasingly unradiogenic up-section. This progressive change in ocean chemistry is coincident with flooding of the Hispanic Corridor, formed during rifting of the Pangean supercontinent and creation of the Central Atlantic Ocean, evident from sudden levels of faunal exchange between the eastern Pacific and western Tethyan oceans. The Os isotope signal here reflects the onset of hydrothermal activity associated with formation of the Hispanic Corridor. New Ni stable isotope data presented herein for the Sinemurian-Pliensbachian (S-P) GSSP and the Devonian-Mississippian Exshaw Formation, demonstrates that organic-rich marine sediments are characterised by δ60Ni values that are distinct to those of extraterrestrial and abiotic terrestrial samples. Further, the level of Ni isotope fractionation in organic-rich sediments (ranging from ~1.32 ‰ in the S-P sediments, and ~2.04 ‰ in the Exshaw Formation) is far greater than that seen in the other sample suites (ranges of ~0.17 – 0.37 ‰; Cameron et al., 2009). Although there are limited datasets available for comparison at present, the ranges of δ60Ni values for the S-P GSSP and Exshaw Formation are similar (0.28 ± 0.05 to 1.60 ±0.05 ‰ and 0.46 ± 0.04 to 2.50 ± 0.04 ‰, respectively), suggesting that such variation in Ni isotope fractionation may be characteristic of organic-rich sediments. This may be due to complexities that are ubiquitous to the sediment-seawater depositional environment. In addition, trace element ratios utilised to establish depositional paleoredox conditions demonstrate that redox did not exert control on the level of Ni isotope fractionation observed in these sediments. The study herein also demonstrates that thermal maturation of the Exshaw Formation has a negligible effect on Ni isotope systematics in mature source rocks, strongly suggesting that Ni isotopes may have the potential to be developed as an oil-source correlation tool.

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34

Madrigal, Quesada Maria Del Pilar. "Mantle melting processes: evidences from ophiolites, large igneous provinces, and intraplate seamounts." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/81071.

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Melting processes in the mantle have a key role in plate tectonics and in the most colossal phenomena in the Earth, like large igneous provinces, mantle plume upwellings, and the constant growth of the planet's tectonic plates. In this study we use the geochemical and petrological evidence preserved in ophiolites, large igneous provinces, and intraplate seamounts to understand causes, timing and implications of melting in these different tectonic environments. We studied melting at extensional environments, in mid-ocean ridges and back-arc basins, preserved in ophiolites. The Santa Elena Ophiolite in Costa Rica comprises a well-preserved fragment of the lithospheric mantle that formed along a paleo-spreading center. Petrological models of fractional crystallization suggest deep pressures of crystallization of >0.4 GPa for most of the samples, in good agreement with similar calculations from slow/ultra-slow spreading ridges and require a relatively hydrated (~0.5 wt% H2O) MORB-like source composition. Our findings suggest a complex interplay between oceanic basin and back-arc extension environments during the Santa Elena Ophiolite formation. Secondly, we analyzed large igneous provinces and their mechanisms of formation. As the surface expression of deep mantle processes, it is essential to understand the time frames and geodynamics that trigger these massive lava outpourings and their impact to life in the planet. We analyze the record and timing of preserved fragments of the Pacific Ocean Large Igneous Provinces to reconstruct the history of mantle plume upwellings and their relation with a deep-rooted source like the Pacific Large Low Shear Velocity Province during the Mid-Jurassic to Upper Cretaceous. Lastly, we explore the occurrence of low-volume seamounts unrelated to mantle plume upwellings and their geochemical modifications as they become recycled inside the mantle, to answer questions related to the nature and origin of upper mantle heterogeneities. We present evidence that an enriched mantle reservoir composed of recycled seamount materials can be formed in a shorter time period than ancient subducted oceanic crust, thought to be the forming agent of the HIMU mantle reservoir endmember. A "fast-forming" enriched reservoir could explain some of the enriched signatures commonly present in intraplate magmas not related with an active mantle plume upwelling.
Ph. D.

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35

Ver, Hoeve Thomas James. "Applications of LA-ICP-MS analysis to zircon : assessing downhole fractionation and pre-treatment effects for U-Pb geochronology and trace element variations in accessory minerals from the Bushveld Complex." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/60201.

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Zircon and other U-Th-Pb-bearing minerals are now recognized as key geochemical and geochronological tracers of the evolution of late-stage fractionated interstitial melt in mafic layered intrusions. Two separate, yet complementary, applications of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) on zircon from layered intrusions are presented with the goals of advancing the analytical capabilities of LA-ICP-MS and showcasing the powerful geochemical fingerprinting of zircon. The effects of downhole fractionation, the time-dependent evolution of Pb-U ratios during laser ablation, represents a significant limitation on the accuracy of U-Th-Pb zircon geochronology by LA-ICP-MS. Exponential downhole correction models developed from the analyses of three common zircon reference materials (Plešovice, Temora-2, 91500) and applied to low-U zircon from Precambrian mafic intrusions (Laramie, Bushveld, Stillwater) indicate that successful correction requires careful matrix-matching the reference zircon to the unknowns. Pre-treatment protocols, including annealing and leaching, applied to all analyzed zircon produces strong effects on downhole fractionation with correlative impact on the relative accuracy of the calculated ages as a function of the downhole behaviour in the reference material used. In the Paleoproterozoic Bushveld Complex, the world’s largest layered intrusion, the trace element systematics of zircon provide temperature-composition constraints on the near-solidus crystallization of mafic-ultramafic cumulates and overlying granitic rocks. Zircon occurs with other late-stage interstitial minerals (e.g., quartz, biotite, Na-plagioclase) and crystallized at temperatures ranging from 950°C down to 690°C based on Ti-in-zircon thermometry. Forward modeling using rhyolite-MELTS of proposed Bushveld parental magmas yields similar zircon saturation temperatures from melts of intermediate-silicic composition, representing less than ~15% remaining melt, and reproduces the observed mineral assemblages. Anomalously high and variable Th/U in zircon from the Critical Zone (e.g., UG2 chromitite, Merensky Reef) reflects U loss to late, oxidized Cl-rich fluids that exsolved from the fractionated interstitial melt, a process that may be a characteristic feature of large open-system layered intrusions (e.g., Neoarchean Stillwater Complex). The presence of late-stage interstitial zircon and other accessory minerals in layered intrusions provides new in situ geochemical and geochronological tools for evaluating the origin and evolution of mafic-ultramafic magmatism in the Earth’s crust throughout geological time.
Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate

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36

Dell'Oro, Trent Arthur. "Sr-Nd-Hf-Pb isotope and trace element geochemistry of the Natkusiak Formation continental flood basalts of the Neoproterozoic Franklin large igneous province, Victoria Island, Canada." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43518.

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The Neoproterozoic (ca. 723 Ma) Franklin large igneous province (LIP) located on Victoria Island, Arctic Canada, consists of the Natkusiak Formation continental flood basalts and a sill-dominated feeder system exposed in the Minto Inlier. The Franklin LIP is temporally linked with the breakup of Laurentia from Siberia and the Sturtian glaciation or “Snowball Earth”. Recent mapping shows that the Natkusiak Formation, preserved in two lobes (northern and southern), has a thin basal unit, ~50 m thick, followed by two ~500 m thick cycles (1 and 2) of basaltic sheet-flows. Sr-Nd-Pb-Hf isotopic compositions, major element oxides, and trace element concentrations of the Natkusiak basalts allow for the characterization of mantle source components and the extent of crustal contamination. Four geochemical groups (southern low- and high-Ti basalts; northern low- and high-Ti basalts) are defined. The basal basalts (low-Ti, 1.0-1.2 wt.% TiO₂) are distinguished from the overlying cycle 1 and 2 basalts (high-Ti, 1.2-1.8 wt.% TiO₂). The high-Ti basalts are characterized by a narrow range in ⁸⁷Sr/⁸⁶Sri (0.7027-0.7045), high εNdi and εHfi, and relatively low ²⁰⁶Pb/²⁰⁴Pbi, ²⁰⁷Pb/²⁰⁴Pbi, and ²⁰⁸Pb/²⁰⁴Pbi compared to the low-Ti basalts (⁸⁷Sr/⁸⁶Sri = 0.7033-0.7057). The northern (low- and high-Ti) basalts are isotopically distinct from the southern (low- and high-Ti) basalts with lower εNdi values for a given ⁸⁷Sr/⁸⁶Sri. The chemistry of the coeval Franklin intrusions mainly overlaps that of the northern basalts and they show only limited isotopic correlation with the southern basalts, which indicates that the southern basalts were fed from a separate feeder system. Significant major and trace element and isotopic differences between the low- and high-Ti basalts are inconsistent with the effects of crustal contamination and are related to different mantle source compositions, with a garnet-bearing source for the low-Ti basalts and a spinel-bearing source for the high-Ti basalts. A shift in mantle source region, likely reflected by an episode of syn-volcanic extension, occurred after the emplacement of the low-Ti basalts, which represent the earliest volcanic products of the Franklin LIP.

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37

Williams, Branwen. "Biogeochemistry of Soft Corals and Black Corals, and Implications for Paleoceanography in the Western Tropical Pacific." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244743730.

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38

Pierce, Natashia M. "Geochemical and isotopic discrimination of meta-volcanics from the Rowe-Hawley Zone of western New England: A discussion of along-strike translation of tectonic models." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378112536.

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39

Bull, Julia Ruth. "Stable isotope, major and trace element chemistry of modern snow from Evans Piedmont Glacier, Antarctica : insights into potential source regions and relationship of glaciochemistry to atmospheric circulation and vigour : a thesis submitted to the Victoria University of Wellington in partial fulfilment of the requirements for the degree of Master of Science in Geology /." ResearchArchive@Victoria e-Thesis, 2009. http://hdl.handle.net/10063/1124.

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40

Merschel, Gila [Verfasser], Michael [Akademischer Betreuer] [Gutachter] Bau, Andrea [Gutachter] Koschinsky-Fritsche, Elton Luiz [Gutachter] Dantas, and Per [Gutachter] Andersson. "Trace Element and Isotope Geochemistry of Particle-Reactive Elements in River Waters of the Amazon River Basin / Gila Merschel ; Gutachter: Michael Bau, Andrea Koschinsky-Fritsche, Elton Luiz Dantas, Per Andersson ; Betreuer: Michael Bau." Bremen : IRC-Library, Information Resource Center der Jacobs University Bremen, 2017. http://d-nb.info/1132813557/34.

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41

McGuire, Sara Anne. "Noxious Smoke and Silent Killers: Identity, Inequality, Health, and Pollutant Exposure During England’s Industrial Revolution." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1594403381913239.

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42

Dia, Aline. "Sediments et evolution geochimique (evolution de la croute continentale et etude de la limite cretace-tertiaire) : contraintes apportees par l'analyse isotopique (neodyme et plomb) et les teneurs en elements traces." Paris 7, 1988. http://www.theses.fr/1988PA077050.

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L'utilisation d'analyses isotopiques (nd et pb) et des teneurs en elements-trace a permis d'aborder plusieurs aspects de la geochimie des roches sedimentaires. On s'interesse a l'aspect temporel enregistre par les sediments avec la caracterisation de la croissance de la croute continentale et l'etude de son evolution chimique au cours du temps (afrique du sud et canada). L'autre aspect etudie concerne l'individualisation des contributions respectives des sources de particules sedimentaires (etude isotopique de la limite cretace-tertiaire, evolution geochimique du bassin oceanique marocain), les concentrations secondaires ou les phenomenes de circulation

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43

Farmer, Lucian P. "Trace element characteristics of zircon : a means of assessing mineralization potential of intrusions in northern Nevada." Thesis, 2012. http://hdl.handle.net/1957/36276.

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Oxidized hydrous intermediate composition magmas are responsible for porphyry copper (Cu ±Mo ±Au) deposits and epithermal Au ore deposits formed globally in the shallow crust (Sillitoe, 2010; Seedorff et al., 2005). Recently, zircon geochemistry has been used to characterize both productive and barren intrusions associated with porphyry Cu-Au ore deposits. Zircon composition differs slightly between the two intrusive groups, and researchers have proposed that zircon in productive intrusions has crystallized from a relatively more oxidized melt compared to barren intrusions (Ballard et al., 2002; Muñoz et al., 2012). Zircon rare earth elements record anomalies in Ce and Eu contents that allow estimation of the ratio of oxidized versus reduced species, i.e. Ce⁴⁺/Ce³⁺ (Ce[superscript IV]/Ce[superscript III]) and Eu³⁺/Eu²⁺ (Eu/Eu*)[subscript CN]. This study focuses on understanding the compositions of Eocene magmas associated with sediment hosted Carlin gold deposits and the gold-copper ores of the Battle Mountain porphyry Cu-Au-skarn district in northern Nevada. Zircon trace element composition was analyzed using LA-ICP-MS and SHRIMP-RG to determine differences between mineralizing and non-mineralizing intrusions in northern Nevada and to compare these compositions with known porphyry Cu-Au type magmas. These zircon and rock compositional data was then used to test the hypothesis of a magmatic origin of the Carlin type gold deposits (Muntean et al., 2011). Zircon U-Pb ages were calculated using multiple SHRIMP-RG spot analyses of each sample for two Carlin biotite porphyry dikes, two Battle Mountain porphyry dikes and the granodiorite of the Copper Canyon stock. The new U-Pb age dates for Carlin porphyry dikes are 38.7 ± 0.5 Ma and 38.8 ± 0.4 Ma. The age of the Copper Canyon stock is 38.0 ± 0.7 Ma, and the age of the Battle Mountain porphyry dikes are 40.2 ± 0.4 Ma and 41.3 ± 0.4 Ma. The Carlin dike ages are the same age, within uncertainty, with previous studies conducted (Mortensesn et al., 2000). The productive porphyry dikes from the Battle Mountain district have Ce(IV)/Ce(III) ratios of 500 to 10000 and a wide range of (Eu/Eu*)[subscript CN] values between 0.3 and 0.7 respectively. Carlin porphyry dikes have Ce(IV)/Ce(III) values between 100 and 1000, and a more limited (Eu/Eu*)[subscript CN] range of 0.5 to 0.7. Barren Eocene intrusions at Harrison Pass and Caetano have much lower Ce(IV)/Ce(III) ratios that range from 20 to 500, and have a very large span of (Eu/Eu*)[subscript CN] from 0.03 to 0.6. Calculated Ce(IV)/Ce(III) and (Eu/Eu*)[subscript CN] of zircon of this study illustrate a distinction between productive and barren intrusions in northern Nevada, and demonstrate a geochemical link between porphyry type magmas and dikes associated with Carlin type gold deposits. These ratios may provide a useful means of evaluating potentially economic geologic terranes and serving as a method to infer relative oxidation state of zircon bearing intrusive rocks.
Graduation date: 2013

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Hofmann, Amy Elizabeth. "Micron- to Sub-Micron-Scale Trace Element Zonations in Zircon and Olivine." Thesis, 2010. https://thesis.library.caltech.edu/5856/1/AE_Hofmann_thesis.pdf.

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Sub-micron-scale zoning of Ti concentrations and correlations between concentrations of Ti and other trace elements (P, Ce, and Y) and cathodoluminescent (CL) banding is observed in natural zircons of both unknown (e.g., Jack Hills) and known (e.g., Toba and Bishop Tuffs) provenance. Ion images were made using the Caltech Microanalysis Center’s CAMECA NanoSIMS 50L with an O- primary beam focused to ~400–600 nm on the sample surface. The high spatial resolution of this technique allows for interrogation of chemical variations at or below the scale of CL banding in natural zircons. Images produced in this manner display several types of correlations among Ti, P, Ce, and Y (which appears to be a proxy for CL intensity): positive correlations between Ti concentrations, concentrations of some subset of the other trace elements (P, Ce, and Y), and cathodoluminescent (CL) zonations; Ti inversely correlated with P, Y, and Ce (all of which track oscillatory CL bands); no correlations between CL zones and either Ti or the other trace elements. Three possible causes for such correlations include: temperature-dependent equilibrium partitioning, trace-element partitioning limited by diffusion in the host melt, and surface-controlled, non-equilibrium growth. Comparison of our data with the expected results of these processes suggests that: 1) Ti partitioning in zircon is dependent upon non-equilibrium effects in addition to temperature and/or 2) the incorporation of elements that co-vary with Ti in zircon (e.g., Y, P and Ce) is also temperature-dependent.

To explore these hypotheses, we performed a series of experiments on synthetic and natural granitic compositions (enriched in TiO₂ and ZrO₂) at temperatures of 1400, 1300, and 1200°C. All liquids were zircon-saturated and 6 of the 16 experimental glasses were also saturated in rutile. NanoSIMS measurements of Ti in zircon overgrowth rims in our experiments range from 760 to 112 ppm and show a positive correlation with TiO₂ content of the quenched glass and run temperature. Our Ti-in-zircon values when “adjusted” for SiO₂ and TiO₂ melt activities (i.e., log(Ti-in-zircon, ppm)+log(α_SiO₂)-log(α_TiO₂) show a strong inverse correlation with 1/T; and least squares fits to the two sets of data generated in this study (synthetic bulk compositions and natural bulk compositions) yield equations with slopes that are statistically indistinguishable. This suggests that at temperatures above 1200°C other trace elements in the melt do not appear to have a substantial effect on Ti partitioning between zircon and silica-rich liquid. A weighted global fit to all of our experimental data is:
log(Ti-in-zircon, ppm)+log(α_SiO₂)-log(α_TiO₂) = (6.21 ± 0.43)-(5918 ± 689)/T (K).
R² for this equation is 0.85. Our Ti glass contents coupled with measured zircon Ti concentrations from the same experiments allow us to calculate a zircon-melt Ti partition coefficient. Our measured D^zre/melt_Ti values are 0.014 to 0.029 and are broadly consistent with values determined from natural-zircon glass pairs. We note that, in the cases for which zircon-independent temperature constraints are known for a parental liquid, neither of the current Ti-in-zircon thermometry calibrations can explain Ti variations in natural zircons as documented by the NanoSIMS.

In Chapter 4, we document spatially correlated P, Al, and Cr zoning in 36 of 40 Gorgona komatiitic olivines from three textural units: a jointed flow top, two random spinifex zones, and two oriented plate spinifex zones. P zoning is observed to be decoupled from or inversely correlated with Al and Cr zoning in some olivines from all three units; the type of zoning observed (e.g., oscillatory, sector) varies depending on textural type. Cooling-rate experiments were performed on a synthetic haplo-komatiite bulk composition in order to evaluate the physical parameters governing incorporation of P, Al, and Sc (as a proxy for Cr) in spinifex komatiitic olivines. Cation-cation plots of data from the natural olivines reveal strong linear trends between Al and Cr and suggest that Al and Cr enter the olivine crystal lattice in a 2:1 ratio. Trends in P-Al and P-Cr composition space differ depending on the olivine textural type. With one exception, oriented plate spinifex olivines define a sub-horizontal P-Al and P-Cr trend, which suggests that P is being accommodated into the olivine lattice via a substitution mechanism involving both Al and Cr. The outlier from this population is a rare preserved plate spinifex tip, which records much higher P at low Al and Cr concentrations compared to the other plate spinifex grains; we interpret these data as suggestive of P incorporation in excess of equilibrium values due to rapid crystal growth.

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LI, JI-YU, and 李寄嵎. "Trace element geochemistry of major basaltic rocks from Penghu area." Thesis, 1985. http://ndltd.ncl.edu.tw/handle/81576376260318820815.

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HUANG, HUI-HUA, and 黃慧華. "Trace element geochemistry of Kungkuan stage basaltic rocks from northern Taiwan." Thesis, 1987. http://ndltd.ncl.edu.tw/handle/20764740128696069259.

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CHEN, SHU-ZHEN, and 陳淑珍. "Isotope and trace element geochemistry of neogene basaltic rocks in western Taiwan." Thesis, 1988. http://ndltd.ncl.edu.tw/handle/56798872378886646339.

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Moran, Ann Elizabeth. "The effect of metamorphism on the trace element composition of subducted oceanic crust and sediment." Thesis, 1993. http://hdl.handle.net/1911/16653.

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Metasedimentary and metabasaltic rocks of the Pelona schist of Sierra Pelona, southern California, preserve a relatively high P/T inverted metamorphic gradient (Graham and Powell, 1984) and provide an opportunity to study possible compositional changes in an oceanic slab progressively metamorphosed under P-T conditions similar to those in shallow parts of some subduction zones. Progressive metamorphism resulted in continuous major element compositional change in plagioclase, white mica, amphibole, and epidote. Variations in whole-rock compositions do not correlate with increasing metamorphic grade and largely appear to reflect protolith heterogeneity. Loss of H$\sb2$O-rich fluid during chlorite breakdown reactions largely accounts for the decrease in weight percent LOI and H content with increasing metamorphic grade. Comparison with unmetamorphosed equivalents and lower temperature, high-pressure metamorphic rocks (including metabasaltic samples from the Shuksan schist and the Franciscan Complex) suggest that As and Sb may be lost from metasedimentary rocks and that B may be lost from metabasaltic rocks at temperatures less than 450$\sp\circ$C. Trace element analyses obtained by ion microprobe for minerals in the Pelona, Catalina, and Shuksan schists document the mineral residencies of trace elements and the redistribution of trace elements among minerals as modal abundances vary. Boron, Ba, Li, Rb, and Cs are strongly concentrated in micas. In samples with coexisting white mica and biotite, higher concentrations of B, Ba, and Sr are observed in white mica, relative to Li, Rb, and Cs, which preferentially substitute into biotite. Cesium and Rb partition in a relatively constant ratio between white mica and biotite. Strontium is strongly concentrated in epidote, but is increasingly incorporated into white mica and plagioclase as the modal abundance of epidote decreases and as plagioclase compositions become more calcic. Similarly, Li appears to be repartitioned into amphibole as chlorite decreases in modal abundance. These observations support a model of gradual release of fluid-mobile trace elements during progressive metamorphism (as from subducted slabs). Prograde continuous reactions involving mica may particularly control the mobility of alkali and alkaline earth elements enriched in arc magmas and provide a mechanism for fractionating incompatible element ratios (e.g. B/Cs) during subduction zone metamorphism.

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"The Petrogenesis of Angrites and Martian Meteorites Inferred from Isotope and Trace Element Systematics." Doctoral diss., 2012. http://hdl.handle.net/2286/R.I.15845.

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abstract: The present understanding of the formation and evolution of the earliest bodies in the Solar System is based in large part on geochemical and isotopic evidences contained within meteorites. The differentiated meteorites (meteorites originating from bodies that have experienced partial to complete melting) are particularly useful for deciphering magmatic processes occurring in the early Solar System. A rare group of differentiated meteorites, the angrites, are uniquely suited for such work. The angrites have ancient crystallization ages, lack secondary processing, and have been minimally affected by shock metamorphism, thus allowing them to retain their initial geochemical and isotopic characteristics at the time of formation. The scarcity of angrite samples made it difficult to conduct comprehensive investigations into the formation history of this unique meteorite group. However, a dramatic increase in the number of angrites recovered in recent years presents the opportunity to expand our understanding of their petrogenesis, as well as further refine our knowledge of the initial isotopic abundances in the early Solar System as recorded by their isotopic systematics. Using a combination of geochemical tools (radiogenic isotope chronometers and trace element chemistry), I have investigated the petrogenetic history of a group of four angrites that sample a range of formation conditions (cooling histories) and crystallization ages. Through isotope ratio measurements, I have examined a comprehensive set of long- and short-lived radiogenic isotope systems (26Al-26Mg, 87Rb-87Sr, 146Sm-142Nd, 147Sm-143Nd, and 176Lu-176Hf) within these four angrites. The results of these measurements provide information regarding crystallization ages, as well as revised estimates for the initial isotopic abundances of several key elements in the early Solar System. The determination of trace element concentrations in individual mineral phases, as well as bulk rock samples, provides important constraints on magmatic processes occurring on the angrite parent body. The measured trace element abundances are used to estimate the composition of the parent melts of individual angrites, examine crystallization conditions, and investigate possible geochemical affinities between various angrites. The new geochemical and isotopic measurements presented here significantly expand our understanding of the geochemical conditions found on the angrite parent body and the environment in which these meteorites formed.
Dissertation/Thesis
Ph.D. Geological Sciences 2012

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Seyedali, Minasadat. "An investigation of low-temperature off-axis hydrothermal systems using lithium isotopes and trace element geochemistry." Thesis, 2020. http://hdl.handle.net/1828/12262.

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This dissertation contributes to our understanding of the use of the Li-isotopic composition of seawater as a tracer of the earth system with a focus on the role of low-temperature hydrothermal systems within the lava section of the ocean crust. Experiments were conducted to study the exchange coefficient (D(Li/Ca)) and isotopic fractionation factor (α; 1000ln(α)=Δ) for lithium between inorganic calcite and an aqueous solution as a function of solution chemistry. These experiments show that, under the conditions used, D(Li/Ca) negatively correlates with solution H+/Ca2+ ratio (and the solution pH) and Δ positively correlates with solution pH. The change in D(Li/Ca) with solution chemistry is interpreted as indicating that Li is incorporated into calcite as LiHCO3, and hence depends on solution H+/Ca2+. A series of diffusion experiments were performed to test whether changes in pH led to changes in the aqueous Li speciation that would lead to changes in the relative diffusivity of the two Li-isotopes, but no such changes were observed. It is proposed that the change in Δ with changing solution pH may either reflect a kinetic or equilibrium isotope fractionation associated with changing solution chemistry. These results have important implications for interpreting the Li content of calcite that has undergone any diagenetic modification. The Li-content and isotopic composition of rocks altered by low-temperature, off-axis hydrothermal systems in the upper oceanic crust were studied to better understand the role of these systems in controlling the Li-isotopic composition of seawater. Results of a detailed study of DSDP Holes 417A, 417D and 418A from 119 Myr Western North Atlantic Ocean basin show that the Li content of the lavas decreases with depth in the upper ~30 m below sediments while the Li-isotopic composition increases from a low value and then does not show systematic variation in deeper sections. No evidence was found to support a role for a change in mineralogy of alteration products to explain the observed variation in Li composition of lavas. There is also no evidence for the modification of the composition of hydrothermal fluid due to a mixture with sediment pore-fluid. Simple one-dimensional fluid flow and fluid-rock reaction models also cannot explain the observed variation. Instead, a model of free-circulation of seawater through the upper few tens of meters of the lavas, and leakage of modified fluid into the deeper portion of the lava pile seems to explain the observed variations best. To investigate the role of low-temperature off-axis hydrothermal systems on the Li content and isotopic composition of seawater from the Cretaceous to modern era, five DSDP/ODP holes with crustal age spanning from 13.6 to 95 Myr were studied in combination with results from previous studies. Results suggest that the average amount of Li added to the upper oceanic crust decreases, while its average Li-isotopic composition increases, from the Cretaceous to the modern. The simplest explanation for these variations may be a decrease in Li concentration and an increase in Li-isotopic composition, of seawater over this time interval.
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Dissertations / Theses on the topic 'Zircon trace element geochemistry'

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