Geology

AbstractThe early Paleoproterozoic (ca. 2.5–2.2 Ga) represents a critical juncture in Earth history, marking the inception of an oxygenated atmosphere while bearing witness to potentially multiple widespread and severe glaciations. Deciphering the natu…

AbstractSiliciclastic stromatolites are rare in the geologic record, and their occurrence recorded in the literature is restricted to marine and coastal environments. The Upper Jurassic Guará Formation, from the Paraná Basin in southern Brazil, hosts u…

AbstractLittle evidence of macrofossil charcoal, a wildfire proxy, is recorded from upper Lower to lowermost Upper Devonian rocks. Coals of this age are few, and petrographic data indicate low volumes (<10% mineral-matter free) of charcoal. This pau…

AbstractThe Gabilan mesa tilts gently southwest away from the San Andreas fault in central California (western United States). Rather than attributing its existence to plate convergence, we argue that this large landform developed in response to a chan…

AbstractThe complexities of convergent margins commonly include the interactions of subduction zones, with many geological records of “double” subduction. Here, we build two-dimensional numerical models to explore the evolution of complex subduction sy…

AbstractStromatoporoids were major reef-builders during the middle Paleozoic; however, no Carboniferous stromatoporoid reefs have been reported. The Akiyoshi Limestone Group of southwest Japan formed on a seamount in the Panthalassa Ocean from the Miss…

AbstractMicrobial methanogenesis from crude oil is an important source of CH4 for gas reservoirs and atmospheric greenhouse gases. However, its petrological records have not been found in natural environments, and the geological conditions under which …