Results 81 to 90 of about 12,911 (237)
New Zealand Journal of Geology and Geophysics, Volume 69, Issue 2, June 2026.Clasts of albite‐porphyroblastic quartzofeldspathic schist, derived from the Otago Schist basement, occur within the Port Chalmers Breccia, a diatreme at the centre of the Dunedin stratovolcano, New Zealand. Schists have undergone varying degrees of replacement reactions (at temperatures of 300° to >500°C) producing hornfelses, with Ca‐ and K‐enriched ...
Alan F. Cooper
wiley +1 more source
Estratigrafía del Grupo Mina Verdun, Proterozoico de Minas, Uruguay
Latin American Journal of Sedimentology and Basin AnalysisEl objetivo del presente trabajo es el de presentar un cuadro estratigráfico para las sedimentitas del área del Cerro Verdún, Minas, Uruguay. Asimismo presentar algunas consideraciones sobre sus características sedimentológicas y sus estromatolitos, a ...
Daniel G. Poiré +3 more
doaj
Anomalous supply of bioessential molybdenum in mid-Proterozoic surface environments [PDF]
, 2016 Granites aged 1.9 Ga to 1.5 Ga exhibit molybdenite mineralization globally. Sandstones deposited during the mid-Proterozoic have a provenance dominated by 1.9–1.7 Ga basement.
Parnell, John, Lindgren, Paula
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The United States Magnetotelluric Array and the National Impedance Map
Reviews of Geophysics, Volume 64, Issue 2, June 2026.Abstract The United States Magnetotelluric Array (USMTArray) data set, collected in the years 2006–2024, consists of more than 1,700 long‐period magnetotelluric stations covering the entirety of the contiguous United States on a quasi‐regular 70 km grid.
Anna Kelbert +7 more
wiley +1 more source
Geochronology of sillimanite-cordierite gneiss Atamanovo series of the South Yenisei Ridge (Russia)
Литосфера, 2017 The paper provides justification of Paleo Archaean age (3221 ± 15 Ma) of the granulite plutonic metamorphism that formed the Kan metamorphic complex of the Archaean crust in the Angara-Kan block of the Siberian craton. The age was defined on the basis of
A. M. Sazonov +6 more
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The Astronomical JournalThe chemical makeup of Earth’s atmosphere during the Archean (4–2.5 Ga) and Proterozoic eon (2.5–0.5 Ga) contrast considerably with the present-day: the Archean was rich in carbon dioxide and methane, and the Proterozoic had potentially higher amounts of
Armen Tokadjian, Renyu Hu, Mario Damiano
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A seismic study of the mid- and lower-crust beneath the sea of Bothnia: BABEL line 1 [PDF]
, 1994 In the Autumn of 1989, Durham University took part in the BABEL Project, a collaboration of scientists from five nations recording wide angle and normal incidence seismic data in the Baltic Shield.
Graham, Daniel P.
core
Molybdenum isotope evidence for widespread anoxia in mid-Proterozoic oceans.
, 2004 How much dissolved oxygen was present in the mid-Proterozoic oceans between 1.8 and 1.0 billion years ago is debated vigorously. One model argues for oxygenation of the oceans soon after the initial rise of atmospheric oxygen approximately 2.3 billion ...
Barling, Jane +4 more
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Chemostratigraphy of Neoproterozoic carbonates: implications for 'blind dating' [PDF]
, 2001 The delta C-13(carb) and Sr-87/Sr-86 secular variations in Neoproteozoic seawater have been used for the purpose of 'isotope stratigraphy' but there are a number of problems that can preclude its routine use.
Gorokhov, I.M. +8 more
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Geochemistry, Geophysics, Geosystems, Volume 27, Issue 6, June 2026.Abstract The cratonic lithospheric mantle records complex metasomatic processes and is frequently tapped by alkaline magmatism, offering a unique opportunity to trace the progressive evolution of the mantle. In the present contribution, we investigate a newly identified calc‐alkaline lamprophyre field from the Neoarchean Jonnagiri Schist Belt, Eastern ...
Sourav Naskar +6 more
wiley +1 more source