Results 31 to 40 of about 9,387 (221)

Zircon and apatite U-Pb geochronology of the Paleoproterozoic (Eburnean) basement and late Neoproterozoic (Pan-African) metamorphism and magmatism from Port-Béni, Armorican Massif (France)

open access: yesBSGF - Earth Sciences Bulletin
By re-examining the historical outcrops of Port-Béni located in the Trégor unit of the North Armorican Cadomian belt, the present work delivers four new ages that provide additional constraints on the Proterozoic history of northern Brittany.
Poujol Marc   +3 more
doaj   +1 more source

(Table 1) Geochemical composition of the Mazagan granodiorite at DSDP Hole 79-544A

open access: yes, 1984
(Table 1) Geochemical composition of the Mazagan granodiorite at DSDP Hole 79 ...
Kreuzer, H   +7 more
core   +1 more source

Genetic relationships between skarn ore deposits and magmatic activity in the Ahar region, Western Alborz, NW Iran

open access: yesGeologica Carpathica, 2014
Paleocene to Oligocene tectonic processes in northwest Iran resulted in extensive I-type calc-alkaline and alkaline magmatic activity in the Ahar region.
Mollai Habib   +2 more
doaj   +1 more source

Petrography, geochemistry and zircon U-Pb geochronology of the Siderian-Rhyacian granitoids of NW Bacajá Domain, Amazonian Craton

open access: yesJournal of the Geological Survey of Brazil, 2022
Archean and Paleoproterozoic granitoids with different geochemical affinities are widely distributed in the basement of high-grade metamorphic rocks of the Bacajá Domain, which consists of Rhyacian granite-greenstone terrain with Archean-Siderian ...
Cleberson Vieira da Silva   +2 more
doaj   +1 more source

The emplacement and deformation of granitic rocks in a transpressional shear zone: the ox mountains igneous complex [PDF]

open access: yes, 1989
The structural evolution of the Ox Mountains Granodiorite {478±12Ma) during and after its emplacement is described. This pluton has been emplaced within and synchronously with, a major transpressional shear zone which is expressed as a 11km wide belt of ...
McCaffrey, Kenneth J.W., McCaffrey, K.J
core  

Geochemistry and Geochronology of Magmatic Rocks in Southwestern and Northeastern Cambodia: Implications for the Tectonic Evolution and Metallogenesis of the Loei Fold Belt

open access: yesGeological Journal, EarlyView.
The composition of intrusive rocks suggests that the magma was likely generated in a subduction‐related setting. The arc crustal thickness in the Phnom Sro Ngam and Halo Prospects was probably < 40 km during emplacement. Zircon U–Pb age range indicates a correlation with Loei Fold Belt magmatic activity.
Sirisokha Seang   +6 more
wiley   +1 more source

A Reassessment of Petrochemistry of ~1.2 Ga Tonalitic Rocks of the Northern Tugela Terrane, Natal Metamorphic Belt, South Africa: Further Constraints on the Evolution of This Belt

open access: yesGeological Journal, EarlyView.
Our petrochemical studies on ~1.2 Ga granitoids of the Natal Metamorphic Belt, South Africa, do not suggest any property similar to Phanerozoic‐style subduction‐related granitoids. Plot of Kotongweni Tonalite in Y versus Sr diagram (after Moyen 2011), note that most samples have Sr/Y < 50.
Palesa Leuta   +2 more
wiley   +1 more source

Heterogeneous Exhumation Mechanisms in Neoproterozoic Collisional Metamorphism: P–T Constraints From Pelotas and Punta del Este Terranes, Southern Brazil and Uruguay

open access: yesGeological Journal, EarlyView.
Petrography, thermobarometry, and pseudosection modelling reveal peak metamorphic conditions of 3–7.5 kbar and 520°C–800°C in Tonian‐Cryogenian orthogneisses of the Dom Feliciano Belt. Metamorphic field gradients of 27°C/km–39°C/km and variable exhumation mechanisms support correlation of these units as remnants of a Himalayan‐type Piratini Orogeny ...
Thaiane Niederauer‐Santos   +6 more
wiley   +1 more source

Depositional and Hydrological Relationships Between Buried Dead Ice and the Active Layer in the McMurdo Dry Valleys, Antarctica: A Study of Sediment Geochemistry and Cation Concentrations

open access: yesPermafrost and Periglacial Processes, EarlyView.
ABSTRACT The McMurdo Dry Valleys, the largest ice‐free region in Antarctica, are home to a cold‐desert hydrologic system of glaciers, snowbanks, streams, and lakes. Freshwater is also stored as dead glacial ice, which is poorly constrained in terms of ion concentrations and interactions with both in situ and overlying sediments.
Matthew C. Witscheber, Kate M. Swanger
wiley   +1 more source

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