Negative carbon isotope excursions from a new record of terrestrial organic carbon (dCorg= 2.3x) and from marine carbonate (d13Ccarb= 0.8x) were used to calculate a methane hydrate release of 1137 Gt of carbon over ~1 Myr during the early Aptian (Early Cretaceous). We show how the coincident and sudden near-cessation of subduction along the northern boundaries of the Farallon plate resulted in ...

Earthquakes far from tectonic plate boundaries generally exploit ancient faults, but not all intraplate faults are equally active. The North American Great Plains exemplify such intraplate earthquake localization, with both natural and induced seismicity generally clustered in discrete zones. Here we use seismic velocity, gravity and topography to generate a 3D lithospheric density model of the...

Places are inherently dynamic. The boundaries of administrative regions (e.g., provinces and countries) and natural regions (e.g., coastlines, ecosystems, mountains, ice sheets, tectonic plates) can alter over time, as can their names. Cities have a daily influx and egress of people and vehicles, buildings go up and down, streets sometimes get repaired, added, etc. Even when a place persists, i...

Species richness gradients are ubiquitous in nature, but the mechanisms that generate and maintain these patterns at macroecological scales remain unresolved. We use a new approach that focuses on overlapping geographical ranges of species to reveal that Indo-Pacific corals are assembled within 11 distinct faunal provinces. Province limits are characterized by co-occurrence of multiple species ...

The Earth’s tectonic plates are strong, viscoelastic shells which make up the outermost part of a thermally convecting, predominantly viscous layer; at the boundaries between plates the rheology is thought to be dominated by brittle processes. Brittle failure of the lithosphere occurs when stresses are high. In order to build a realistic simulation of the planet’s evolution, the complete viscoe...

Presented here are the first three-dimensional simulations of mantle convection to display self-consistently-generated plate tectonic-like behavior which is continuous in space and time. Plate behavior arises through a reasonable material description of silicate deformation, with a simple yield stress being sufficient to give first-order plate-like behavior. Toroidal:poloidal ratios are within ...

the iranian plateau is characterized by diverse tectonic domains, including the continental collisions (e.g. the zagros and alborz mountains) and oceanic plate subduction (e.g. makransubduction zone). to derive a detailed image of the crust–mantle (moho) and lithosphere–asthenosphere (lab) boundaries in some tectonically units of the iranian plateau, we used a large number of s receiver functio...

Introduction: Planar deformation features (PDFs) in quartz are diagnostic impact evidence. Using light microscopy, it is often impossible to distinguish between PDFs and tectonic deformation lamellae. [1] showed that PDFs can be imaged using a cathodoluminescence (CL) detector in a scanning electron microscope (SEM) and that in SEM-CL images PDFs can be distinguished from tectonic microfracture...

The relationship between plate boundary forces and the observed stress field in the Pacific Northwest is established using numerical niodels of continental deformation. Because the orientation of the greatest horizontal principal stress throughout the Pacific Northwest differs considerably from the direction of convergence between the Juan de Fuca and North American plates. the relationship haw...

The surface of Venus displays several tectonized terrains in which the morphologic characteristics of the original materials are almost completely erased by superposed tectonic structures whose large dimensions (»100 km) suggest formation related to mantle convection. The characteristics of these tectonized terrains are in contrast to volcanic units in which tectonic structures are less signifi...