Abstract The Archean ocean supported a diverse microbial ecosystem, yet studies suggest that seawater was largely depleted in many essential nutrients, including fixed nitrogen. This depletion part consequence of inefficient nutrient recycling under anoxic conditions. Here, we show how hydrothermal fluids acted as mechanism for ammonium (NH4+) the ocean. We present elemental and stable isotope ...

Abstract When the modern-like geomorphology and climate pattern of Himalaya-Tibetan Plateau were established still remains unclear. In this study, we apply paired stable isotope compositions carbonate (δ18Oc) leaf waxderived n-alkanes (δ2Halk) from upper Gazhacun Formation in Namling Basin to reconstruct middle Miocene elevation southern Tibet. Depositional age has been precisely constrained be...

TheOrdovician volcanic and intrusive rocks of the Cadia–Neville region, in the southern Molong Volcanic Belt section of the Macquarie Arc in central-western New South Wales, display a temporal progression from shoshonitic basaltic volcanism (e.g. Mt Pleasant Basalt Member) in the late Darriwilian to Gisbornian (ca 460–453 Ma) to small-volume dacitic medium-K calc-alkaline magmatism (e.g. Copper...

Zircon ages and trace element compositions from recent silicic eruptions in the Lassen Volcanic Center (LVC) allow for an evaluation of the timing and conditions of rejuvenation (reheating and mobilization of crystals) within the LVC magmatic system. The LVC is the southernmost active Cascade volcano and, prior to the 1980 eruption of Mount St. Helens, was the site of the only eruption in the C...

Continental magmatic arcs form above subduction zones where the upper plate is continental lithosphere and/or accreted transitional lithosphere. The best-studied examples are found along the western margin of the Americas. They are Earth’s largest sites of intermediate magmatism. They are long lived (tens to hundreds of millions of years) and spatially complex; their location migrates laterally...

Two fundamentally different types of silicic volcanic rocks formed during the Cenozoic of the western Cordillera of the United States. Large volumes of dacite and rhyolite, mostly ignimbrites, erupted in the Oligocene in what is now the Great Basin and contrast with rhyolites erupted along the Snake River Plain during the Late Cenozoic. The Great Basin dacites and rhyolites are generally calc-a...