Geology

AbstractThree-dimensional magnetotelluric (MT) imaging in central Colorado reveals a set of north-striking high-conductivity tracks at lower-crustal (50–20 km) depths, with conductive finger-like structures rising off these tracks into the middle crust…

AbstractThe Cascade arc (western North America) is the world’s youngest continental arc, and because the down-going Juan de Fuca plate is young, it is also the hottest end member among subduction zones worldwide. We present evidence that the arc initia…

AbstractSubduction polarity reversal usually involves the break off or tearing of the downgoing plate (DP) along the continent-ocean transition zone, in order to initiate subduction of the overriding plate (OP) with opposite polarity. We propose that s…

AbstractThe Sturtian “Snowball Earth” glaciation (ca. 717–661 Ma) is regarded as the most extreme interval of icehouse climate in Earth’s history. The exact trigger and sustention mechanisms for this long-lived global glaciation remain obscure. The mos…

AbstractClinopyroxene is a rock-forming mineral that commonly hosts melt inclusions in mafic to intermediate composition volcanic and plutonic rocks. It is highly resistant to alteration compared to other co-existing phenocrysts such as plagioclase. Se…

AbstractVolcanic regions commonly host swarms comprising small to moderate-sized earthquakes while tectonic faults host mostly mainshock-aftershock sequences that can include very large earthquakes. In the southeastern Tibetan Plateau, large tectonic f…

AbstractThe Paleocene–Eocene thermal maximum (PETM), a transient period of global warming, is considered to be an important analog for future greenhouse conditions. It was accompanied by a significant carbon cycle perturbation. Although ocean deoxygena…