Academic literature on the topic 'Geology, Stratigraphic Proterozoic'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Geology, Stratigraphic Proterozoic.'

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.

Journal articles on the topic "Geology, Stratigraphic Proterozoic"

1

Phillips, Bruce J., Alan W. James, and Graeme M. Philip. "THE GEOLOGY AND HYDROCARBON POTENTIAL OF THE NORTH-WESTERN OFFICER BASIN." APPEA Journal 25, no. 1 (1985): 52. http://dx.doi.org/10.1071/aj84004.

Full text
Abstract:
Recent petroleum exploration in EP 186 and EP 187 in the north-western Officer Basin has greatly increased knowledge of the regional stratigraphy, structure and petroleum prospectivity of the region. This exploration programme has involved the drilling of two deep stratigraphic wells (Dragoon 1 and Hussar 1) and the acquisition of 1438 km of seismic data. Integration of regional gravity and aeromagnetic data with regional seismic and well data reveals that the Gibson Sub-basin primarily contains a Proterozoic evaporitic sequence. In contrast, the Herbert Sub-basin contains a Late Proterozoic t
APA, Harvard, Vancouver, ISO, and other styles
2

Martins-Neto, Marcelo A. "Sequence stratigraphic framework of Proterozoic successions in eastern Brazil." Marine and Petroleum Geology 26, no. 2 (February 2009): 163–76. http://dx.doi.org/10.1016/j.marpetgeo.2007.10.001.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Cosgrove, G. I. E., L. Colombera, and N. P. Mountney. "Eolian stratigraphic record of environmental change through geological time." Geology 50, no. 3 (November 22, 2021): 289–94. http://dx.doi.org/10.1130/g49474.1.

Full text
Abstract:
Abstract The terrestrial sedimentary record provides a valuable archive of how ancient depositional systems responded to and recorded changes in Earth's atmosphere, biosphere, and geosphere. However, the record of these environmental changes in eolian sedimentary successions is poorly constrained and largely unquantified. Our study presents the first global-scale, quantitative investigation of the architecture of eolian systems through geological time via analysis of 55 case studies of eolian successions. Eolian deposits accumulating (1) under greenhouse conditions, (2) in the presence of vasc
APA, Harvard, Vancouver, ISO, and other styles
4

Alsop, G. I. "The geometry and structural evolution of a crustal-scale Caledonian fold complex: the Ballybofey Nappe, northwest Ireland." Geological Magazine 131, no. 4 (July 1994): 519–37. http://dx.doi.org/10.1017/s0016756800012139.

Full text
Abstract:
AbstractThe gross geometries exhibited by crustal-scale fold nappes are considered a consequence of both original stratigraphic relationships associated with sub-basin configuration, coupled with the nature of the structural regime and tectonic processes involved in the generation of the nappe pile. The Neo-Proterozoic Dalradian metasediments of northwestern Ireland provide a well-constrained and correlatable stratigraphy which defines a sequence of sub-reclined, tight-isoclinal Caledonian (c. 460 Ma) fold nappes. Within this fold complex, the dominant structure is the crustal-scale Ballybofey
APA, Harvard, Vancouver, ISO, and other styles
5

GEHLING, JAMES G., SÖREN JENSEN, MARY L. DROSER, PAUL M. MYROW, and GUY M. NARBONNE. "Burrowing below the basal Cambrian GSSP, Fortune Head, Newfoundland." Geological Magazine 138, no. 2 (March 2001): 213–18. http://dx.doi.org/10.1017/s001675680100509x.

Full text
Abstract:
The range of Treptichnus pedum, the index trace fossil for the Treptichnus pedum Zone, extends some 4 m below the Global Standard Stratotype-section and Point for the base of the Cambrian Period at Fortune Head on the Burin Peninsula in southeastern Newfoundland. The identification of zigzag traces of Treptichnus isp., even further below the GSSP than T. pedum in the Fortune Head section, and in other terminal Proterozoic successions around the globe, supports the concept of a gradational onset of three-dimensional burrowing across the Proterozoic–Cambrian boundary. Although T. pedum remains a
APA, Harvard, Vancouver, ISO, and other styles
6

GEYER, G. "The Fish River Subgroup in Namibia: stratigraphy, depositional environments and the Proterozoic–Cambrian boundary problem revisited." Geological Magazine 142, no. 5 (September 2005): 465–98. http://dx.doi.org/10.1017/s0016756805000956.

Full text
Abstract:
The Fish River Subgroup of the Nama Group, southern Namibia, is restudied in terms of lithostratigraphy and depositional environment. The study is based on partly fine-scaled sections, particularly of the Nababis and Gross Aub Formation. The results are generally in accordance with earlier studies. However, braided river deposits appear to be less widely distributed in the studied area, and a considerable part of the formations of the middle and upper subgroup apparently were deposited under shallowest marine conditions including upper shore-face. Evidence comes partly from sedimentary feature
APA, Harvard, Vancouver, ISO, and other styles
7

Kulikov, V. S., V. V. Kulikova, and A. K. Polin. "NEW CHRONOSTRATIC SCHEME OF SOUTH-EASTERN FENNOSCANDIA AND ITS USE IN THE PREPARATION OF SMALL-SCALE GEOLOGICAL MAPS OF THE PRECAMBRIAN REGIONS." Proceedings of higher educational establishments. Geology and Exploration, no. 5 (October 28, 2017): 5–12. http://dx.doi.org/10.32454/0016-7762-2017-5-5-12.

Full text
Abstract:
A new chronostratic scheme of South-East (SE) Fennoscandia has been developed, based on the International Stratigraphie Scale, taking into account some elements of the Common Stratigraphic Scale of Russia and the regional stratigraphic scheme of the North-West (NW) of Russian Federation. A rank of Archean and Proterozoic stratons has been determined (including supersystems for Riphean and Archean geonotems), compatable in dutation to the Phanerozoic systems (Mesozoic and Paleozoic ones). An original coloring for the geological maps of the newly allocated systems and their analogues in the Prec
APA, Harvard, Vancouver, ISO, and other styles
8

Jackson, J., I. P. Sweet, and T. G. Powell. "STUDIES ON PETROLEUM GEOLOGY AND GEOCHEMISTRY, MIDDLE PROTEROZOIC, McARTHUR BASIN NORTHERN AUSTRALIA I: PETROLEUM POTENTIAL." APPEA Journal 28, no. 1 (1988): 283. http://dx.doi.org/10.1071/aj87022.

Full text
Abstract:
Mature, rich, potential source beds and adjacent potential reservoir beds exist in the Middle Proterozoic sequence (1400-1800 Ma) of the McArthur Basin. The McArthur and Nathan Groups consist mainly of evaporitic and stromatolitic cherty dolostones interbedded with dolomitic siltstone and shale. They were deposited in interfingering marginal marine, lacustrine and fluvial environments. Lacustrine dolomitic siltstones form potential source beds, while potential reservoirs include vuggy brecciated carbonates associated with penecontemporaneous faulting and rare coarse-grained clastics. In contra
APA, Harvard, Vancouver, ISO, and other styles
9

HARLAND, W. BRIAN. "Origins and assessment of snowball Earth hypotheses." Geological Magazine 144, no. 4 (June 6, 2007): 633–42. http://dx.doi.org/10.1017/s0016756807003391.

Full text
Abstract:
Brian Harland was for many years an editor of this journal. He was also a seminal figure in the origins of the current ‘snowball Earth’ debate, having recognized in 1964 the significance of coupling emerging palaeomagnetic data on palaeolatitude with his interpretations of diamictites. Harland worked extensively in the Arctic and knew well many of the workers involved in the arguments surrounding the origin of diamictites. He thus had a unique perspective on the evidence and the disputes surrounding it. This was his last paper but he was not able to complete it before he died. However, with th
APA, Harvard, Vancouver, ISO, and other styles
10

Green, J. W., A. H. Knoll, and K. Swett. "Microfossils from silicified stromatolitic carbonates of the Upper Proterozoic Limestone-Dolomite 'Series', central East Greenland." Geological Magazine 126, no. 5 (September 1, 1989): 567–85. http://dx.doi.org/10.1017/s0016756800022858.

Full text
Abstract:
AbstractSilicified flake conglomerates andin situstratiform stromatolites of the Upper Proterozoic (c.700–800 Ma) Limestone-Dolomite ‘Series’, central East Greenland, contain well preserved microfossils. Five stratigraphic horizons within the 1200 m succession contain microbial mat assemblages, providing a broad palaeontological representation of late Proterozoic peritidal mat communities. Comparison of assemblages demonstrates that the taxonomy and diversity of mat builder, dweller, and allochthonous populations all vary considerably within and among horizons. The primary mat builder in most
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "Geology, Stratigraphic Proterozoic"

1

Strauss, Toby Anthony Lavery. "The geology of the Proterozoic Haveri Au-Cu deposit, Southern Finland." Thesis, Rhodes University, 2004. http://hdl.handle.net/10962/d1015978.

Full text
Abstract:
The Haveri Au-Cu deposit is located in southern Finland about 175 km north of Helsinki. It occurs on the northern edge of the continental island arc-type, volcano-sedimentary Tampere Schist Belt (TSB) within the Palaeoproterozoic Svecofennian Domain (2.0 – 1.75 Ga) of the Fennoscandian Shield. The 1.99 Ga Haveri Formation forms the base of the supracrustal stratigraphy consisting of metavolcanic pillow lavas and breccias passing upwards into intercalated metatuffs and metatuffites. There is a continuous gradation upwards from the predominantly volcaniclastic Haveri Formation into the overlying
APA, Harvard, Vancouver, ISO, and other styles
2

Li, Longming, and 李龙明. "The crustal evolutionary history of the Cathaysia Block from the paleoproterozoic to mesozoic." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B45693596.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Baldim, Maurício Rigoni 1983. "O domo gnáissico Alto Alegre, transição embasamento-greenstone belt do Rio Itapicuru : evolução e significado tectônico." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/286596.

Full text
Abstract:
Orientador: Elson Paiva de Oliveira<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências<br>Made available in DSpace on 2018-08-26T10:50:20Z (GMT). No. of bitstreams: 1 Baldim_MauricioRigoni_M.pdf: 19163752 bytes, checksum: da3d83e0ed883c0984d79ed906f0528c (MD5) Previous issue date: 2014<br>Resumo: Domos gnáissicos são estruturas que podem estar associadas tanto aos orógenos extensionais quanto aos colisionais. Em orógenos colisionais, normalmente balizam os distintos terrenos dispondo-se em corredores estruturais. Na região nordeste do Cráton São Francisco
APA, Harvard, Vancouver, ISO, and other styles
4

Baghiyan-Yazd, Mohammad Hassan. "Palaeoichnology of the terminal Proterozoic-Early Cambrian transition in central Australia : interregional correlation and palaeoecology." Title page, table of contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phb1445.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Johnson, Shannon D. "Structural geology of the Usakos Dome in the Damara Belt, Namibia." Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/50457.

Full text
Abstract:
Thesis (MSc)--Stellenbosch University, 2005.<br>ENGLISH ABSTRACT: The northeast-trending south Central Zone (sCZ) of the Pan-African Damara belt in central Namibia is structurally characterized by kilometer-scale, northeast-trending dome structures developed in Neoproterozoic rocks of the Damara Sequence. A number of different structural models have been proposed for the formation of these domes in the literature. This study describes the structural geology of the Usakos dome. The study discusses the structural evolution of the dome within the regional framework of the cSZ that represen
APA, Harvard, Vancouver, ISO, and other styles
6

Zhao, Junhong, and 趙軍紅. "Geochemistry of neoproterozoic arc-related plutons in the Western margin of the Yangtze Block, South China." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40203748.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Wang, Wei, and 王伟. "Sedimentology, geochronology and geochemistry of the proterozoic sedimentary rocks in the Yangtze Block, South China." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/196033.

Full text
Abstract:
The South China Craton comprises the Yangtze Block in the northwest and Cathaysia Block in the southeast. Located in the southeastern Yangtze Block, the Jiangnan Orogen formed through the amalgamation between the Yangtze and Cathaysia Blocks. The Yangtze Block has sporadically exposed Archean rocks in the north, Paleoproterozoic to Mesoproterozoic volcano-sedimentary sequences in the southwest and widespread Neoproterozoic sedimentary sequences accompanied by syn-sedimentary igneous rocks on the western and southeastern margins. The late Paleoproterozoic to early Mesoproterozoic Dongchuan, Da
APA, Harvard, Vancouver, ISO, and other styles
8

Harris, Charles William. "A sedimentological and structural analysis of the Proterozoic Uncompahgre Group, Needle Mountains, Colorado." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/79644.

Full text
Abstract:
Siliciclastic sediments of the Proterozoic Uncompahgre Group can be subdivided into stratigraphic units of quartzite (Q) and pelite (P); these units include a basal, fining- and thinning-upward retrogradational sequence (Q1-P1) that records the transition from an alluvial to a shallow-marine setting. Overlying the basal sequence are three thickening- and coarsening-upward progradational sequences (P2-Q2, P3-Q3 and P4-Q4) that were influenced by tide-, storm- and wave-processes. The progradational units are subdivided into the following facies associations in a vertical sequence. Outer-to inner
APA, Harvard, Vancouver, ISO, and other styles
9

Hill, Robert E. (Robert Einar). "Stratigraphy and sedimentology of the Middle Proterozoic Waterton and Altyn Formations, Belt-Purcell Supergroup, southwest Alberta." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63330.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Gibson, R. G. "Structural studies in a Proterozoic gneiss complex and adjacent cover rocks, west Needle Mountains, Colorado." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/76096.

Full text
Abstract:
Proterozoic rocks in the Needle Mountains include ca. 1750 Ma amphibolite-grade, metavolcanic and metaplutonic gneisses and ca. 1690 Ma granitoids that comprise the basement to the siliciclastic Uncompahgre Group. The mafic and felsic gneisses underwent synkinematic metamorphism and two phases of isoclinal folding and foliation development during D<sub>B</sub>, prior to emplacement of the ca. 1690 Ma plutons. D<sub>BC</sub> deformation caused folding of D<sub>B</sub> fabrics in the gneisses, development of a subvertical, east-striking foliation in the granitoids, and generation of a macroscopi
APA, Harvard, Vancouver, ISO, and other styles
More sources

Books on the topic "Geology, Stratigraphic Proterozoic"

1

1936-, Medaris L. G., and Geological Society of America, eds. Proterozoic geology: Selected papers from an International Proterozoic Symposium. Boulder, Colo: Geological Society of America, 1986.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

F, Gower Charles, Rivers Toby 1948-, Ryan Arthur Bruce 1951-, and Geological Association of Canada, eds. Mid-Proterozoic Laurentia-Baltica. St. John's, Nfld., Canada: Geological Association of Canada, Dept. of Earth Sciences, 1990.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
3

Blake, D. H., fl. 1967-, ed. Geology of the Proterozoic Davenport province, central Australia. Canberra: Australian Government Publishing Service, 1987.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

A, Grambling Jeffrey, Tewksbury Barbara J, and Geological Society of America. Rocky Mountain Section., eds. Proterozoic geology of the southern Rocky Mountains. Boulder, Colo: Geological Society of America, 1989.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
5

Uppermost Proterozoic formations in central Mackenzie Mountains, Northwest Territories. Ottawa, Ont., Canada: Energy, Mines and Resources Canada, 1989.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

Dawes, Peter R. The Proterozoic Thule Supergroup, Greenland and Canada: History, lithostratigraphy, and development. Copenhagen, Denmark: Geological Survey of Denmark and Greenland, Ministry of Environment and Energy, 1997.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
7

A, Winchester J., ed. Later Proterozoic stratigraphy of the northern Atlantic regions. Glasgow: Blackie, 1988.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
8

Greene, Robert C. Stratigraphy of the Late Proterozoic Murdama Group, Saudi Arabia. [Menlo Park, CA: U.S. Geological Survey], 1993.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
9

J, Frarey M. Proterozoic geology of the Lake Panache-Collins Inlet area, Ontario. Ottawa, Canada: Geological Survey of Canada, 1985.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
10

Blacet, Philip M. Proterozoic geology of the Brady Butte area, Yavapai County, Arizona. [Reston, Va.?]: Dept. of the Interior, U.S. Geological Survey, 1985.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Book chapters on the topic "Geology, Stratigraphic Proterozoic"

1

Young, Grant M. "Earth's Earliest Extensive Glaciations: Tectonic Setting and Stratigraphic Context of Paleoproterozoic Glaciogenic Deposits." In The Extreme Proterozoic: Geology, Geochemistry, and Climate, 161–81. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/146gm13.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Mitra, Sumit Kumar. "The Lithological, Stratigraphical, Structural Control of Quartzites Hosting Sulphide Mineralisation in the Proterozoic Shillong Group, Meghalaya, India." In The Structural Geology Contribution to the Africa-Eurasia Geology: Basement and Reservoir Structure, Ore Mineralisation and Tectonic Modelling, 49–53. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-01455-1_11.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

LUND, KAREN I., and RUSSELL G. TYSDAL. "Stratigraphic and Structural Setting of Sediment-Hosted Blackbird Gold–Cobalt–Copper Deposits, East-Central Idaho, U.S.A." In Proterozoic Geology of Western North America and Siberia, 129–47. SEPM (Society for Sedimentary Geology), 2007. http://dx.doi.org/10.2110/pec.07.86.0129.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Rowland, Stephen M. "Geology of Frenchman Mountain and Rainbow Gardens, southern Nevada, USA." In Field Excursions from Las Vegas, Nevada: Guides to the 2022 GSA Cordilleran and Rocky Mountain Joint Section Meeting, 23–43. Geological Society of America, 2022. http://dx.doi.org/10.1130/2022.0063(02).

Full text
Abstract:
ABSTRACT This field guide synthesizes more than a half century of research by many geologists and paleontologists on Frenchman Mountain and Rainbow Gardens, southern Nevada, USA. The field-trip consists of seven stops to be visited in one day. The guide was written not only for field-trip participants on the occasion of the 2022 ­Cordilleran/Rocky Mountain Geological Society of America Joint Section Meeting in Las Vegas, but also with future users in mind. The Frenchman Mountain/Rainbow Gardens block of crust exposes an extraordinary sample of Earth history. The geologic features include (1) Proterozoic crystalline rocks, (2) the Great Unconformity, (2) a Paleozoic interval that is essentially a ­tilted section of the western Grand Canyon, (3) a Mesozoic interval that preserves strata that were eroded off the southern Colorado Plateau during the Miocene “Great Denudation” episode, and (4) a Cenozoic section that records a wealth of paleo­climatic, paleontological, and tectonic data. Among the many stories that are recorded in the rocks of the Frenchman Mountain/Rainbow Gardens block, I have chosen three to emphasize in this field guide: (1) the history recorded in the Proterozoic Vishnu Basement Complex and the Great Unconformity; (2) the stratigraphy, sedimentology, paleontology, and geochronology of the Cambrian Tonto Group [with a focus on (a) trilobite biostratigraphy in the Bright Angel Formation, (b) the significance of the abundance of glauconite in the Tonto Group, and (c) the Frenchman Mountain Dolostone]; and (3) the tectonic story recorded in the Thumb Member of the Horse Spring Formation. The basement rocks record events and processes associated with the assembly of supercontinents Nuna and Rodinia. The Great Unconformity records the breakup of Rodinia and the associated denudation interval that played a role in triggering the Cambrian explosion. The Tonto Group, which was recently expanded to include the Frenchman Mountain Dolostone, records the Sauk Transgression. And the Thumb Member of the Horse Spring Formation contains rock avalanche deposits that have played a key role in sorting out the tectonic history of the southern Nevada region and the translational history of the Frenchman Mountain/Rainbow Gardens block.
APA, Harvard, Vancouver, ISO, and other styles
5

Datsenko, Liudmyla, and Serhii Kolomiiets. "GROUNDWATERS OF NIKOLSKOHO REGION (DONBASS): GEOLOGY, STRATIGRAPHY, HYDROGEOLOGY, TOPOGRAPHIC AND GEODESIC WORKS." In State, trends and prospects of land sciences, environment, physics, mathematics and statistics’ development (1st. ed). Primedia eLaunch LLC, 2020. http://dx.doi.org/10.36074/stplsepmad.ed-1.03.

Full text
Abstract:
Arid regions of the south of Ukraine (Donetsk, Zaporizhia, Kherson regions) are facing an acute shortage of drinking and technical water, which consumption increases from year to year. A clear understanding of the shortage not only drinking water but also water for fish breeding, cultural and recreational needs is worrying the world scientific community. Understanding of hydrogeological, hydrogeochemical processes is important for groundwater protection, especially in arid regions of the world. The study area is located within the central part of the Priazovsk highland. Administratively, it belongs to Nikolsk Region (formerly Volodarsky Region) in Donetsk Region. There are four research periods in geological mapping and study of the Eastern and North-Western Priazovia region. The most important researches of the late last century include medium-size deep geological mapping of the North-Western and Eastern Priazovia, generalization of all geological materials of the previous researchers, obtaining data from stratigraphy, magmatism, tectonics and metallogeny, hydrogeology, which allowed to significantly clarify the geological structure of the region. The only possible centralized water supply source on the most part of the territory may be an aquifer of Proterozoic crystalline rocks. In the south-eastern part of the territory can be used Sarmatian sands, sandstones and limestone horizon, for the aquifer of crystalline rocks, the most water-rich is the tectonic disturbance zone with open fracturing.
APA, Harvard, Vancouver, ISO, and other styles
6

WINSTON, DON. "Revised Stratigraphy and Depositional History of the Helena and Wallace Formations, Mid-Proterozoic Piegan Group, Belt Supergroup, Montana and Idaho, U.S.A." In Proterozoic Geology of Western North America and Siberia, 65–100. SEPM (Society for Sedimentary Geology), 2007. http://dx.doi.org/10.2110/pec.07.86.0065.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Smith, Alan L., M. John Roobol, Glen S. Mattioli, George E. Daly, and Joan E. Fryxell. "Providencia Island: A Miocene Stratovolcano on the Lower Nicaraguan Rise, Western Caribbean—A Geological Enigma Resolved." In Providencia Island: A Miocene Stratovolcano on the Lower Nicaraguan Rise, Western Caribbean—A Geological Enigma Resolved, 1–101. Geological Society of America, 2021. http://dx.doi.org/10.1130/2021.1219(01).

Full text
Abstract:
ABSTRACT The Providencia island group comprises an extinct Miocene stratovolcano located on a shallow submarine bank astride the Lower Nicaraguan Rise in the western Caribbean. We report here on the geology, geochemistry, petrology, and isotopic ages of the rocks within the Providencia island group, using newly collected as well as previously published results to unravel the complex history of Providencia. The volcano is made up of eight stratigraphic units, including three major units: (1) the Mafic unit, (2) the Breccia unit, (3) the Felsic unit, and five minor units: (4) the Trachyandesite unit, (5) the Conglomerate unit, (6) the Pumice unit, (7) the Intrusive unit, and (8) the Limestone unit. The Mafic unit is the oldest and forms the foundation of the island, consisting of both subaerial and subaqueous lava flows and pyroclastic deposits of alkali basalt and trachybasalt. Overlying the Mafic unit, there is a thin, minor unit of trachyandesite lava flows (Trachyandesite unit). The Breccia unit unconformably overlies the older rocks and consists of crudely stratified breccias (block flows/block-and-ash flows) of vitrophyric dacite, which represent subaerial near-vent facies formed by gravitational and/or explosive dome collapse. The breccias commonly contain clasts of alkali basalt, indicating the nature of the underlying substrate. The Felsic unit comprises the central part of the island, composed of rhyolite lava flows and domes, separated from the rocks of the Breccia unit by a flat-lying unconformity. Following a quiescent period, limited felsic pyroclastic activity produced minor valley-fill ignimbrites (Pumice unit). The rocks of Providencia can be geochemically and stratigraphically subdivided into an older alkaline suite of alkali basalts, trachybasalts, and trachyandesites, and a younger subalkaline suite composed dominantly of dacites and rhyolites. Isotopically, the alkali basalts together with the proposed tholeiitic parent magmas for the dacites and rhyolites indicate an origin by varying degrees of partial melting of a metasomatized ocean-island basalt–type mantle that had been modified by interaction with the Galapagos plume. The dacites are the only phenocryst-rich rocks on the island and have a very small compositional range. We infer that they formed by the mixing of basalt and rhyolite magmas in a lower oceanic crustal “hot zone.” The rhyolites of the Felsic unit, as well as the rhyolitic magmas contributing to dacite formation, are interpreted as being the products of partial melting of the thickened lower oceanic crust beneath Providencia. U-Pb dating of zircons in the Providencia volcanic rocks has yielded Oligocene and Miocene ages, corresponding to the ages of the volcanism. In addition, some zircon crystals in the same rocks have yielded both Proterozoic and Paleozoic ages ranging between 1661 and 454 Ma. The lack of any evidence of continental crust beneath Providencia suggests that these old zircons are xenocrysts from the upper mantle beneath the Lower Nicaraguan Rise. A comparison of the volcanic rocks from Providencia with similar rocks that comprise the Western Caribbean alkaline province indicates that while the Providencia alkaline suite is similar to other alkaline suites previously defined within this province, the Providencia subalkaline suite is unique, having no equivalent rocks within the Western Caribbean alkaline province.
APA, Harvard, Vancouver, ISO, and other styles
8

Şengör, A. M. C. "Eduard Suess on graptolites: His very first scientific paper and illustrations." In The Evolution of Paleontological Art. Geological Society of America, 2021. http://dx.doi.org/10.1130/2021.1218(09).

Full text
Abstract:
ABSTRACT The very first scientific paper by Eduard Suess (1831–1914) treats the graptolites of Bohemia in the present-day Czech Republic (in the Upper Proterozoic to Middle Devonian “Barrandian” extending between Prague and Plzeň). This paper is accompanied by superb drawings of his observations in which Suess took great care not to insert himself between Nature as he perceived it in the framework of the knowledge of his day and his readers. His only limitation was the one imposed by the size of his study objects. His technological means did not allow him to see what we today consider the “right” picture. Nevertheless, we can see what he saw and interpret it through a modern lens of understanding. In his drawings, Suess exercised what the great German geologist Hans Cloos later called “the art of leaving out.” This meant that in the drawings, the parts not relevant to the discussion are left only in outline, whereas parts he wished to highlight are brought to the fore by careful shading. Even the parts left only in outline are not schematic, however; instead they are careful reconstructions true to Nature as much as the material and his technological aids allowed. This characteristic of Suess’ illustrations is seen also in his later field sketches concerning stratigraphy and structural geology and in his depiction of the large tectonic features of our globe representing a window into his manner of thinking.
APA, Harvard, Vancouver, ISO, and other styles
9

Boniface, Nelson, and Tatsuki Tsujimori. "New tectonic model and division of the Ubendian-Usagaran Belt, Tanzania: A review and in-situ dating of eclogites." In Plate Tectonics, Ophiolites, and Societal Significance of Geology: A Celebration of the Career of Eldridge Moores. Geological Society of America, 2021. http://dx.doi.org/10.1130/2021.2552(08).

Full text
Abstract:
ABSTRACT Records of high-pressure/low-temperature (HP-LT) metamorphic interfaces are not common in Precambrian orogens. It should be noted that the association of HP-LT metamorphic interfaces and strongly deformed ocean plate stratigraphy that form accretionary prisms between trenches and magmatic arcs are recognized as hallmark signatures of modern plate tectonics. In East Africa (Tanzania), the Paleoproterozoic Ubendian-Usagaran Belt records a HP-LT metamorphic interface that we consider as a centerpiece in reviewing the description of tectonic units of the Ubendian-Usagaran Belt and defining a new tectonic model. Our new U-Pb zircon age and the interpretations from existing data reveal an age between 1920 and 1890 Ma from the kyanite bearing eclogites. This establishment adds to the information of already known HP-LT metamorphic events at 2000 Ma, 1890–1860 Ma, and 590–520 Ma from the Ubendian-Usagaran Belt. Arc–back-arc signatures from eclogites imply that their mafic protoliths were probably eroded from arc basalt above a subduction zone and were channeled into a subduction zone as mélanges and got metamorphosed. The Ubendian-Usagaran events also record rifting, arc and back-arc magmatism, collisional, and hydrothermal events that preceded or followed HP-LT tectonic events. Our new tectonic subdivision of the Ubendian Belt is described as: (1) the western Ubendian Corridor, mainly composed of two Proterozoic suture zones (subduction at 2000, 1920–1890, Ma and 590–500 Ma) in the Ufipa and Nyika Terranes; (2) the central Ubendian Corridor, predominated by metamorphosed mafic-ultramafic rocks in the Ubende, Mbozi, and Upangwa Terranes that include the 1890–1860 Ma eclogites with mid-ocean ridge basalt affinity in the Ubende Terrane; and (3) the eastern Ubendian Corridor (the Katuma and Lupa Terranes), characterized by reworked Archean crust.
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Geology, Stratigraphic Proterozoic"

1

Bingham-Koslowski, N., L. T. Dafoe, M R St-Onge, E. C. Turner, J. W. Haggart, U. Gregersen, C. E. Keen, A. L. Bent, and J. C. Harrison. Introduction and summary. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/321823.

Full text
Abstract:
The papers contained in this bulletin provide a comprehensive summary and updated understanding of the onshore geology and evolution of Baffin Island, the Labrador-Baffin Seaway, and surrounding onshore regions. This introductory paper summarizes and links the geological and tectonic events that took place to develop the craton and subsequent Proterozoic to Cenozoic sedimentary basins. Specifically, the Precambrian and Paleozoic geology of Baffin Island and localized occurrences underlying the adjacent Labrador-Baffin Seaway, the Mesozoic to Cenozoic stratigraphy and rift history that records
APA, Harvard, Vancouver, ISO, and other styles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!