Results 41 to 50 of about 298,753 (226)

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

Calc-alkaline volcanic rocks and zircon ages of the late Tonian

open access: yes, 2021
The Big Naryn Complex (BNC) in the East Djetim-Too Range of the Kyrgyz Middle Tianshan block is a tectonized, at least 2 km thick sequence of predominantly felsic to intermediate volcanic rocks intruded by porphyric rhyolite sills. It overlies a basement of metamorphic rocks and is overlain by late Neoproterozoic Djetim-Too Formation sediments; these ...
Terbishalieva, Baiansuluu   +8 more
openaire   +3 more sources

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

Local Structures of Se and Br in Cretaceous–Paleogene Boundary Sediments and Concentration Effects of Ferrihydrite Originating From Impact Ejecta

open access: yesGeological Journal, EarlyView.
Chemical states of Se and Br atoms in the KPg boundary sediments from Stevns Klint were studied using XAFS spectroscopy. The high concentrations of Se4+ could become an index of the degree to which the global environment was soiled with dust and ash derived from impact ejecta or volcanic eruptions.
Kei‐ichiro Murai   +5 more
wiley   +1 more source

Geochemistry and tectonic setting of volcanic rocks in Ahovan area, northeast of Semnan (Central Iran) [PDF]

open access: yesپترولوژی
IntroductionVolcanic rocks widely extended throughout the Earth's continental crust (Brilhante et al., 2024). Among the different tectonic setting, a group of igneous rocks is related to volcanic arc; these rocks, according to Tang et al. (2022), include
Saeed Kamran   +4 more
doaj   +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

Petrogenesis and Tectonic Setting of Late Mesozoic Felsic Magmatic Rocks in the Wangmushan Mining District, Northern Fujian, South China

open access: yesGeological Journal, EarlyView.
The rhyolitic ignimbrite and K‐feldspar granite porphyry from the Wangmushan mining district, northern Fujian yield ages of 173.8 ± 0.8 and 102.6 ± 0.4 Ma, respectively. Geochemical data, zircon trace elements, whole‐rock Sr–Nd–Pb isotope data, and zircon Hf isotopic compositions indicate that the rhyolitic ignimbrite originated from partial remelting ...
Wei Shaogang   +7 more
wiley   +1 more source

Geochemistry and tectonic development of Cenozoic magmatism in the Carpathian–Pannonian region [PDF]

open access: yes, 2011
This review considers the magmatic processes in the Carpathian–Pannonian Region (CPR) from Early Miocene to Recent times, as well as the contemporaneous magmatism at its southern boundary in the Dinaride and Balkans regions.
Hilary Downes   +3 more
core   +1 more source

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