AbstractDetermining the age of siliciclastic continental sequences in the absence of comprehensive biostratigraphy or radiometric dating of geological markers (e.g., volcanic layers) is inherently challenging. This issue is well exemplified in the curr…
AbstractSeawater magnesium (Mg) and calcium (Ca) have undergone secular fluctuations throughout the Phanerozoic, controlling whether the dominant calcium carbonate precipitant is calcite or aragonite + high-Mg calcite. Although these oscillations in se…
AbstractProkaryotes, including bacteria, are a major component of both modern and ancient ecosystems. Although fossilized prokaryotes are commonly discovered in sedimentary rocks, it is rare to find them preserved in situ alongside macrofossils, partic…
AbstractWe present a continentwide study of 600 glaciers located on and near 37 ice-clad volcanoes in South America. Results demonstrate glacier sensitivity to volcanic heat. We distinguished between “volcanic glaciers” (≤1 km from volcanic centers; n …
AbstractWe analyzed the first Cu isotopes in primary cupreous pyrite and orpiment, from modern CO2-degassing, seafloor massive sulfide diffuser vents (“KCO2Ds”), from the Kolumbo submarine volcano, Hellenic volcanic arc. Samples came from six KCO2Ds th…
AbstractA new chronology for graphite formation related to subduction-zone metamorphism in Laytonville Quarry (California, USA) of the Franciscan Complex using the Re-Os decay system yields a precise graphite-pyrite Re-Os age of 161.39 ± 2.08 Ma (MSWD …
AbstractRecent research has found that the subsiding Sunda Shelf (Southeast Asia) was permanently exposed prior to ca. 400 ka with initial submersion-exposure cyclicity, associated with interglacial-glacial sea-level cycles, beginning between 400 and 2…
AbstractWe report exceptionally negative δ238U values for spring water (−2.5‰ to −0.8‰) and travertine calcite (−3.2‰ to −1.1‰) from an area where the Jemez lineament intersects the western margins of the Rio Grande rift, west-central New Mexico (south…
AbstractThe relative proportions of carbon, nitrogen, and phosphorus, commonly referred to as the Redfield ratio (106:16:1), have likely varied dramatically through Earth’s history in response to changes in oceanic redox state and nutrient availability…
AbstractCarbonatites, the most silica-poor igneous rocks, have a close relationship with rare earth element (REE) ore deposits, where low SiO2 activity is considered to contribute to economic REE mineralization. However, a paradox is raised by quartz, …