Results 41 to 50 of about 4,534 (235)

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

Gravitational Potential Energy per Unit Area as a Constraint on Archean Sea Level

Geochemistry, Geophysics, Geosystems, 2018
To constrain the density structure of Archean lithosphere, I assume that gravitational potential energy (GPE) per unit area at Archean spreading centers equals that for continents whose surfaces lay near sea level.
Peter Molnar
doaj   +1 more source

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

How lowermost mantle viscosity controls the chemical structure of Earth’s deep interior

Communications Earth & Environment, 2023
Determining the fate of subducted oceanic crust is critical for understanding material cycling through Earth’s deep interior and sources of mantle heterogeneity. A key control on the distribution of subducted slabs over long timescales is the bridgmanite
Juliane Dannberg, Kiran Chotalia, Rene Gassmöller   +2 more
doaj   +1 more source

Tectono‐Sedimentary Evolution of the Neogene İnegöl Basin (NW Anatolia): Constraints on Transtensional Basin Development at the Junction of the Western Anatolian Extensional Province and the North Anatolian Fault Zone

Geological Journal, EarlyView.
The study outlines the tectono‐sedimentary evolution of the İnegöl Basin in north‐western Anatolia. Basin formation was controlled by interacting extensional and strike‐slip fault systems linked to uplift of the Uludağ Massif. Terrestrial sedimentation from the Miocene to Pleistocene is reconstructed using abundant fossil mammal assemblages that ...
M. Cihat Alçiçek, Volkan Karabacak, Serdar Mayda   +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

Geological 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, Akira Yoshiasa, Ginga Kitahara, Makoto Tokuda, Satoko Ishimaru, Toshihiro Moriga   +5 more
wiley   +1 more source

Lateral Evolution of the Deep Crustal Structure of the Lesser Antilles Subduction Zone from Wide-Angle Seismic Modeling

Tektonika
The Lesser Antilles is a subduction zone where devastating earthquakes occur with a long recurrence interval. Here, oceanic lithosphere from the Mid-Atlantic spreading center subducts at a slow convergence velocity of 20 mm/yr underneath the Caribbean ...
Frauke Klingelhoefer, Boris Marcaillou, Muriel Laurencin, Mireille Laigle, Jean-Frédéric Lebrun, Laure Schenini, David Graindorge, Mikael Evain, Heidrun Kopp   +8 more
doaj   +1 more source

Future Scientific Drilling of Oceanic Crust [PDF]

Eos, Transactions American Geophysical Union, 2010
Processes that occur within and across the oceanic crust—in particular along mid‐ocean ridges and oceanic spreading centers—play a huge role in the dynamics of the Earth. The largest fluxes of heat and material between the Earth's mantle, crust, and seawater occur via magmatic, tectonic, and hydrothermal processes along oceanic spreading centers and ...
Hayman, N.W., Bach, W., Blackman, D., Christeson, G.L., Edwards, K., Haymon, R., Ildefonse, Benoit, Schulte, M., Teagle, D., White, S.   +9 more
openaire   +1 more source

Apatite in Carbonatite Preserving Primary Magmatic, Post‐Magmatic Overgrowth, and Post India‐Asia Collision‐Related Hydrothermal Alteration: Evidenced From U–Pb Isotope and Trace Element Geochemistry

Geological Journal, EarlyView.
U–Pb isotope and trace element geochemistry of apatite from carbonatites of Peshawar Plain Alkaline Igneous Province, western Himalaya shows Permo‐Carboniferous magmatism, an additional magmatic pulse during Cretaceous, and post‐magmatic hydrothermal/metasomatism during Oligocene. ABSTRACT U–Pb isotope and trace element geochemistry of apatite combined
Mehboob ur Rashid, Hafiz U. Rehman, Hao‐Yang Lee, Sun‐Lin Chung, Kaushik Das, Kazumasa Aoki, Muhammad Jawad Zeb, Nasir Ahmad, Muhammad Hussain, Hiroshi Yamamoto   +9 more
wiley   +1 more source

Seismic visibility of carbonated subducted oceanic crust in the lower mantle

Communications Earth & Environment
Seismological studies have previously detected abundant scatterers in the lower mantle, potentially linked to long-term slab subduction, and petrology studies suggest carbonates can be sequestrated within the oceanic crust and transported into the lower ...
Yajie Zhao, Xin Deng, Wenzhong Wang, Zhongqing Wu, Ye Yuan   +4 more
doaj   +1 more source