Results 61 to 70 of about 2,123 (183)

Carbonate‐Associated Sulfate Does Not Record Superheavy δ34S in Deep Scandinavian Bedrock Fractures: Implications for Pyrite Formation in the Deep Biosphere

Geochemistry, Geophysics, Geosystems, Volume 27, Issue 8, August 2026.
Abstract In deep bedrock fractures of the Fennoscandian shield, pyrite with “superheavy” δ34S values of up to 147‰ exists together with calcite. The extreme variability and 34S‐enrichment in pyrite indicate that microbial sulfate reduction (MSR) evolved to almost complete sulfate exhaustion in closed‐system microenvironments.
V. Fichtner, F. Genske, E. Kooijman, H. Drake   +3 more
wiley   +1 more source

The first animals: ca. 760-million-year-old sponge-like fossils from Namibia

South African Journal of Science, 2012
One of the most profound events in biospheric evolution was the emergence of animals, which is thought to have occurred some 600-650 Ma. Here we report on the discovery of phosphatised body fossils that we interpret as ancient sponge-like fossils and ...
C. Brain, Anthony Prave, Karl-Heinz Hoffmann, Anthony Fallick, Andre Botha, Donald Herd, Craig Sturrock, Iain Young, Daniel Condon, Stuart Allison   +9 more
doaj  

Geochemical Characteristics and Tectonic Setting of Neoproterozoic Yifeng Formation, Anlelin Formation and Adakitic Meta-quartz Keratophyre in Western Jiangxi Province

Donghua Ligong Daxue Xuebao. Ziran Kexue Ban
[Objective] The Neoproterozoic strata of the Jiuling area in western Jiangxi records the tectonic evolution of the Yangtze and Cathaysia blocks. The study of these strata helps to explore the tectonic setting and evolutionary process of the South China ...
ZHANG Fushen, FU Haiming
doaj   +1 more source

Uplift of the Transantarctic Mountains: Evidence for an Evolving and Long‐Lived Rayleigh‐Taylor Instability

Tectonics, Volume 45, Issue 8, August 2026.
Abstract Rayleigh‐Taylor instabilities within the upper mantle are investigated as a mechanism for the uplift of rift‐margin mountain ranges within the continents. Our focus is on the Transantarctic Mountains (TAM). These mountains form at the margin between East and West Antarctica and have been free from the effects of subduction for about 500 ...
Tim Stern, Simon Lamb, James D. P. Moore, Alec Yates   +3 more
wiley   +1 more source

Provenance of the sedimentary rocks of the Bom Jardim Group (Neoproterozoic, Southern Brazil): Evidence from petrography, geochemistry and neodymium isotopes

Latin American Journal of Sedimentology and Basin Analysis
Provenance studies are helpful in reconstructing the tectonic, climatic and geographic setting of terrigenous sedimentary basins. The primary controls on the composition of detrital sedimentary rocks are the composition, climate and relief conditions of ...
André Weissheimer de Borba, Anderson José Maraschin, Fabio de Lima Noronha, Júnia Casagrande, Ana Maria Pimentel Mizusaki   +4 more
doaj  

Magmatic and tectonic evolution of the Chaval Granite at the end of the Neoproterozoic, northwestern border of the Borborema Province

Brazilian Journal of Geology
The northwestern region of Borborema Province is represented by the Ceara Central and Northwest Ceara crustal blocks connected by an extensive transcurrent shear zone that represents the northern portion of the Transbrasiliano Lineament in a complex ...
Arthur Jeronimo Santana Aragão, Paulo Sergio de Sousa Gorayeb, Marco Antonio Galarza   +2 more
doaj   +1 more source

Early–Late Carboniferous Tectonic Evolution of the Northern North China Craton (NE China): Constraints From Zircon Ages, Geochemistry, and Crustal Thickness Modeling

Geochemistry, Geophysics, Geosystems, Volume 27, Issue 8, August 2026.
Abstract The tectonic evolution of the northern margin of the North China Craton (NCC) remains controversial. In this study, we obtained zircon U–Pb ages, geochemical data, and Sr–Nd isotopic data for volcanic rocks, and detrital zircon ages for sedimentary rocks from the Yufutun, Tongqigou, and Benxi formations in central‐southern Jilin Province, NE ...
Yunfei Chang, Qingxiang Du, Huachun Gan, Xiaoli Shen, Zuozhen Han, Xiaoxue Hou, Huicong Zhang   +6 more
wiley   +1 more source

Cryptic Disc Structures Resembling Ediacaran Discoidal Fossils from the Lower Silurian Hellefjord Schist, Arctic Norway.

PLoS ONE, 2016
The Hellefjord Schist, a volcaniclastic psammite-pelite formation in the Caledonides of Arctic Norway contains discoidal impressions and apparent tube casts that share morphological and taphonomic similarities to Neoproterozoic stem-holdfast forms.
Christopher L Kirkland, Breandán A MacGabhann, Brian L Kirkland, J Stephen Daly   +3 more
doaj   +1 more source

Two Distinct Growth Styles of Riedel Shear Zones in Cratonic Strike‐Slip Fault System, Tarim Basin, NW China

Journal of Geophysical Research: Solid Earth, Volume 131, Issue 8, August 2026.
Abstract The kinematics and progressive evolution of Riedel shear zones have been extensively studied, yet the factors controlling their distinct evolutionary styles in natural settings remain debated. Understanding such fracture network architecture has great implications, such as predicting subsurface fluid flow and assessing seismic hazards.
Jiajun Chen, Zhanfeng Qiao, Tianfu Zhang, Uwe Ring, Shaoying Chang, Peng Cao, Mengxiu Wang, Yifan Du   +7 more
wiley   +1 more source

Exhumation History of the Sangre de Cristo Range, Colorado, From Mid‐ to Low‐Temperature Thermochronology: New Insights Into Laramide Contraction and Oligocene–Miocene Extension in the Northern Rio Grande Rift, USA

Tectonics, Volume 45, Issue 8, August 2026.
Abstract The Sangre de Cristo Range in southern Colorado records a complex tectonic history that includes Late Cretaceous–Eocene Laramide contraction and Oligocene–Quaternary Rio Grande rift extension. We present new thermochronologic data (40Ar/39Ar, fission‐track, (U‐Th)/He) and thermal history models that provide insight into this polyphase history ...
John Singleton, Samantha Malavarca, Alexis K. Ault, Omar Ghamedi, M. Cole Sitar, Paul O’Sullivan, Martin Wong, Jonathan Saul Caine, James Metcalf, Dylan Frawley, Jeffrey M. Rahl   +10 more
wiley   +1 more source