Results 21 to 30 of about 11,453 (209)

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

Geological 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, Khin Zaw, Kakda Kret, Ivan Belousov, Kotaro Yonezu, Koichiro Watanabe, Charles Makoundi   +6 more
wiley   +1 more source

Late Pleistocene Volcanic Rocks From Tengchong Volcanic Field at SE Tibetan Plateau: Constraints on Petrogenesis and Mantle and Crustal Processes

Geological Journal, EarlyView.
Early zircon saturation and crystallisation occur in mafic (52–54 wt.% SiO2) lavas at Tengchong volcanic field. These early formed zircons with high δ18O (6.6‰–7.9‰) indicates mantle enrichment by subducted supracrustal materials. ABSTRACT Late Pleistocene (< 0.2 Ma) mafic and evolved volcanic rocks occur in northern Tengchong Volcanic Field, SE ...
Lizhu Wang, Haibo Zou
wiley   +1 more source

Re-os isotope constraints on the age of the Lithospheric mantle beneath western Greenland. [PDF]

, 2007
Alkaline magmatic activity across Western Greenland (W.G.) provides a record of lithosphere evolution over the last 600 Ma. Ultra Mafic Lamprophyre (UML) magmatism in particular has erupted an exceptional inventory of mantle xenoliths allowing a detailed
Webb, Michelle
core  

Sulfate was a trace constituent of Archean seawater [PDF]

, 2014
In the low-oxygen Archean world (>2400 million years ago), seawater sulfate concentrations were much lower than today, yet open questions frustrate the translation of modern measurements of sulfur isotope fractionations into estimates of Archean ...
Katsev, Sergei, Nomosatryo, Sulung, Crowe, Sean Andrew, Adkins, Jess F., Crowe, Sean A., Paris, Guillaume, Jones, CarriAyne, Canfield, Donald E., Jones, Carri Ayne, Kim, Sang-Tae, Canfield, Donald Eugene; id_orcid, Kim, Sang Tae, Farquhar, James, Zerkle, Aubrey L., Sessions, Alex L., Fowle, David A.   +15 more
core   +1 more source

Archean Domes topology comparison.

, 2022
A. Distributions obtained from simulated random (red), scale-free (blue) and small-world (green) networks and its comparison to the metrics found in the Archean Domes network for: degree variance, modularity, average path length, small-world index, and ...
Jazmín Sánchez-Pérez (12475032), David Madrigal-Trejo (12475047), Valeria Souza (273805), Natalia Favila (12936672), Laura Espinosa-Asuar (5600357), Daniel Legorreta (12936675), Luis E. Eguiarte (8026820)   +6 more
core   +1 more source

Archean geodynamics : Ephemeral supercontinents or long-lived supercratons [PDF]

, 2021
Many Archean cratons exhibit Paleoproterozoic rifted margins, implying they were pieces of some ancestral landmass(es). The idea that such an ancient continental assembly represents an Archean supercontinent has been proposed but remains to be justified.
Liu, Yebo, Pisarevsky, Sergei A., Li, Zheng-Xiang, Wang, Chong, Mitchell, Ross N., Kirscher, Uwe   +5 more
core   +1 more source

Raman Line Scan Analyses and a New Hypothesis for the Formation of Anatase‐Hosting Microbialites: Study of the Stromatolites From Saint‐Jean‐de‐la‐Rivière, Cotentin, France

Journal of Raman Spectroscopy, EarlyView.
Micrometer analysis of millimeter lines of Raman spectra concludes in the association of anatase and graphitized organic matter (graphogen). The photosynthetic microorganisms at the origin of the microbialites produce O2, which is transformed by TiO2 into reactive species that, in turn, decompose the organic matter of the microorganisms. ABSTRACT Raman
Marie‐Paule Bassez
wiley   +1 more source

Time constraints on the formation of lithospheric mantle beneath cratons: a re-Os isotope and platinum group element study of peridotite xenoliths from northern Canada and Lesotho, [PDF]

, 2001
Understanding the generation and evolution of cratonic lithospheric keels requires detailed knowledge of their age, timescale of formation, and the relationship between the crust and mantle part of the lithosphere.
Irvine, Gordon James
core  

Spatial Variability of Permafrost and Active Layer Thickness in a Forested Hillslope of the Taiga Shield

Permafrost and Periglacial Processes, EarlyView.
ABSTRACT Under continued climate warming, understanding present‐day permafrost distribution and the controls on ground thaw are critical for predicting permafrost thaw trajectories and associated implications. This study presents a high‐resolution investigation of permafrost extent and active layer thickness (ALT) across a coniferous forested hillslope
Alana Muenchrath, Christopher Spence, Andrew Ireson   +2 more
wiley   +1 more source

Geodynamic oxidation of Archean terrestrial surfaces

, 2023
One of the paradoxes of the Archean rock record is how evidence for oxidative continental weathering is plausible when the atmosphere lacked oxygen prior to the Great Oxidation Event ca. 2.5 billion years ago.
Zhu, Jianxi, Xiaoju Lin, Xiao Wu, Hongping He, Lingya Ma, Haiyang Xian, Lin, Xiaoju, Liang, Xiaoliang, Jianxi Zhu, Xiaoliang Liang, Ma, Lingya, Yang, Yiping, Wu, Xiao, Xian, Haiyang, Li, Shan, Yiping Yang, He, Hongping, Yiliang Li, Konhauser, Kurt O, Li, Yiliang, Shan Li, Konhauser, Kurt O. O., Kurt O. Konhauser   +22 more
core   +1 more source