Results 51 to 60 of about 16,111 (210)

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

New Schmidt hammer exposure‐age dating calibrations for the Last Glacial Termination in NW Scotland: Development and application to undated Torridon Group sandstone surfaces in Wester Ross

Journal of Quaternary Science, EarlyView.
ABSTRACT An understanding of the terrestrial extent, retreat dynamics and climate–glacier coupling of ice masses during the Last Glacial Termination (LGT, ~18–11 ka) is often limited by a fragmentary geomorphological record and is dependent on precise, accurate and robust dating frameworks.
Alastair M. Curry, David Small, Oliver T. Bartlett, Jonathan Newitt   +3 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

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

A normalised seawater strontium isotope curve: possible implications for Neoproterozoic-Cambrian weathering rates and the further oxygenation of the Earth [PDF]

, 2007
The strontium isotope composition of seawater is strongly influenced on geological time scales by changes in the rates of continental weathering relative to ocean crust alteration.
Shields, GA, Shields, G. A.
core  

Geological constraints on Neoproterozoic glacial episodes [PDF]

, 2023
Neoproterozoic glacial episodes are amongst the most intense glaciations that the Earth has experienced, and are associated with major changes in the Earth System, such as the breakup of a supercontinent, the evolution of complex multicellular life and ...

core   +2 more sources

Quantitative and Nuanced Approaches Elucidate Carbon Isotope Records

Geochemistry, Geophysics, Geosystems
Earth scientists have leveraged carbon isotope records to interpret Earth history and establish chronostratigraphic frameworks for decades (e.g., Halverson et al., 2005, https://doi.org/10.1130/b25630.1; Kaufman & Knoll, 1995, https://doi.org/10.1016 ...
Cedric J. Hagen
doaj   +1 more source

Conditions and timing for the precipitation of early marine diagenetic dolomite in the Triassic Dolomia Principale (northern Italy)

Sedimentology, EarlyView.
ABSTRACT Thermodynamic constraints and empirical evidence often suggest that fabric‐retentive replacement dolomites are stable carbonate minerals that preserve ancient seawater properties. This study evaluates this hypothesis by examining the Upper Triassic Dolomia Principale in Northern Italy.
Vivien Folliot, Giovanna Della Porta, Mathias Mueller, Fabrizio Berra, Benjamin F. Walter, Aratz Beranoaguirre, Sylvia Riechelmann, Oskar Schramm, Adrian Immenhauser   +8 more
wiley   +1 more source

Petrographic and mineralogical characteristics of diagenetic overprinting in Neoproterozoic diamictites from Murchisonfjorden, Nordaustlandet, Svalbard

Mineralogia
The diagenetic processes exhibited by the Neoproterozoic diamictites from Murchisonfjorden (Nordaustlandet, NE Svalbard) are presented. Diamictite samples from the Cryogene Polarisbreen Group - the Petrovbreen Member of the Elbobreen Formation and the ...
Bal Szczepan, Nejbert Krzysztof, Michalski Krzysztof, Domańska-Siuda Justyna, Manby Geoffrey, Hołda-Michalska Aleksandra, Sláma Jiři   +6 more
doaj   +1 more source

Salt Range Formation of Pakistan Preserves Unique Record of Volcanic Fertilization During the Ediacaran Shuram Excursion

Terra Nova, EarlyView.
ABSTRACT Thin, discontinuous, organic‐rich oil shale beds in the siliciclastic‐evaporitic Salt Range Formation (SRF) of Pakistan are of approximate Neoproterozoic to Cambrian age based on stratigraphic constraints. The beds are enriched (26–43 wt.% total organic carbon, TOC) in aliphatic organic matter (OM) of low thermal maturity despite their ...
Paul C. Hackley, Ryan J. McAleer, Jay M. Thompson, Brett J. Valentine, Imran Khan   +4 more
wiley   +1 more source