Results 31 to 40 of about 2,123 (183)

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

Geological 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, Saumitra Misra, Thembiso O. Basupi   +2 more
wiley   +1 more source

A palaeogeographic context for Neoproterozoic glaciation [PDF]

Palaeogeography, Palaeoclimatology, Palaeoecology, 2009
Abstract The distributions of 77 Neoproterozoic glacigenic formations are shown on global palaeogeographic maps for 715 Ma (Sturtian), 635 Ma (Marinoan) and 580 Ma (Ediacaran), constructed on grounds independent of palaeoclimatic indicators. The meridional distribution of Sturtian and Marinoan deposits is biased in favour of low palaeolatitudes ...
Hoffman, P., Li, Zheng-Xiang
openaire   +2 more sources

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

Geological 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, Carla Cristine Porcher, Daniel Triboli Vieira, Edinei Koester, Diego Jaldín, Karina Luengo, Luisa Caon   +6 more
wiley   +1 more source

Zircon SHRIMP U-Pb Dating and Significance From Weathered Residual Kaolin Deposits on the Northern Margin of the Qinzhou-Hangzhou Suture Zone, China

Frontiers in Earth Science, 2022
Weathered residual Kaolin deposits on the northern margin of the Qinzhou-Hangzhou Suture Zone are characterized by more feldspar-containing minerals and fewer dark minerals.
Chunhai Li, Chunhai Li, Chunhai Li, Qifa Sun, Zhonglin Sun, Xiaohua Zhou, Wei Zhang, Rong Chen, Tianshan Gao   +8 more
doaj   +1 more source

Appraisal of Six Natural Mica Reference Materials for In Situ Rb‐Sr Geochronology

Geostandards and Geoanalytical Research, EarlyView.
Key Points Evaluated six natural mica reference materials for in situ LA‐ICP‐MS/MS Rb‐Sr geochronology using geochemical, microstructural and isotopic characterisation. Identified robust primary reference materials: Mount Dromedary biotite (99.37 Ma) and Mica‐Fe biotite (307.75 Ma). La Posta biotite and Högsbo muscovite are suitable secondary reference
Hugo K.H. Olierook, Bruno V. Ribeiro, Janne Liebmann, Kai Rankenburg, Fred Jourdan, Ahmad Redaa, Jarred C. Lloyd, Thomas M. Belgrano, Carlos R. Corella Santa Cruz, Yujin Jegal, Julien Mercadier, Catherine Zimmermann, Jie Yu, Andreas Zametzer, Christopher L. Kirkland, Sarah E. Gilbert, Craig D. Storey, Luc S. Doucet, Isabelle Jones, Louisa Stokes, Thomas Zack, Delia Rösel, Denis Fougerouse, Jonas Kaempf, Priyanjan Datta, Hijas Hameed, Noreen J. Evans, Malcolm P. Roberts, Juraj Farkas, Stijn Glorie, Celia Mayers, R. Adam Frew, Sarah Al Odeh, Chloe E. Roche, Massimo Chiaradia, Alicia M. Cruz‐Uribe, Alan S. Collins, Andreas Karlsson, Anusha Shantha Kumara   +38 more
wiley   +1 more source

Zircon U-Pb dating of the Dizhuanggou Formation, Changjiaoba Group in the South Qinling Belt and its tectonic significance

Dizhi lixue xuebao
Objective  The Changjiaoba Group, located in the Foping area of the South Qinling Belt, is one of the few poorly-studied strata in the belt. The lack of an accurate composition and formation age of these strata has restricted research on the tectonic ...
LIU Zhihui, LIU Xiaochun, CHEN Longyao, ZHENG Guanggao, HU Juan   +4 more
doaj   +1 more source

The Enigma of Neoproterozoic Giant Ooids—Fingerprints of Extreme Climate?

Geophysical Research Letters, 2020
Geologists have documented at least 14 occurrences of “giant ooids,” a geologically rare type of carbonate allochem, in Neoproterozoic successions at low paleolatitudes.
Elizabeth J. Trower
doaj   +1 more source

Geochronology and Lu-Hf isotope of mafic-intermediate rocks from SW Salmas: implication for Neoproterozoic juvenile melts [PDF]

پترولوژی, 2018
The southwest Salmas metamorphosed mafic-intermediate intrusive rocks are located in Sanandaj-Sirjan zone in NW of Iran. The metamorphosed intrusives rocks comprise metagabbro and metadiorite that intruded the Precambrian metamorphosed volcanic ...
Fahime kozekoulani, Mohammad Rahgoshay, Hadi Shafaii Moghadam   +2 more
doaj   +1 more source

(Ultra)high‐Pressure Metamorphism in Sedimentary Versus Basaltic Rocks: Insights From a Variscan Mélange in the South Carpathians

Journal of Metamorphic Geology, EarlyView.
ABSTRACT Reconstructing the pressure–temperature–time (P–T–t) evolution of (ultra)high‐pressure rocks is essential for constraining subduction and collisional dynamics. Subduction zones are often investigated using basic eclogites, whereas nonbasic high‐pressure rocks remain comparatively understudied, potentially hindering a comprehensive ...
Otavio S. G. Silva, Bruno V. Ribeiro, Gavril Săbău, Fabricio Caxito, Paulo A. de Paiva‐Silva, Pierre Lanari, George Luvizotto, Mahyra Tedeschi   +7 more
wiley   +1 more source

A Positive Cooling Feedback for the Neoproterozoic Snowball Earth Initiation Due To Weakening of Ocean Ventilation

Geophysical Research Letters, 2023
Ocean ventilation is an important regulator for atmospheric CO2 level (pCO2) by affecting the relative proportion of carbon stored in the atmosphere and deep ocean.
Peng Liu, Yonggang Liu, Sifan Gu, Paul Hoffman, Sanzhong Li   +4 more
doaj   +1 more source