Research Article| January 01, 2014 Acid rain and ozone depletion from pulsed Siberian Traps magmatism Benjamin A. Black; Black * 1Department of Earth, Atmospheric, Planetary Sciences, Massachusetts Institute Technology, Cambridge, 02139, USA *E-mails: bablack@mit.edu; lamar@ucar.edu; shields@ucar.edu; ltelkins@dtm.ciw.edu; jtkon@ucar.edu. Search for other works by this author on: GSW Google Scholar Jean-François Lamarque; Lamarque 2National Center Atmospheric Research, Boulder, Colorado...

Research Article| March 01, 2013 Fluvial features on Titan: Insights from morphology and modeling Devon M. Burr; Burr † 1Earth Planetary Sciences Department, University of Tennessee–Knoxville, 1412 Circle Drive, Knoxville, Tennessee 37996-1410, USA †E-mail: dburr1@utk.edu Search for other works by this author on: GSW Google Scholar J. Taylor Perron; Perron 2Department Earth, Atmospheric, Sciences, Massachusetts Institute Technology, 77 Avenue, Cambridge, 02139, Michael P. Lamb; Lamb...

Carbon is central to the formation and environmental impact of large igneous provinces (LIPs). These vast magmatic events occur over geologically short timescales include voluminous flood basalts, along with silicic low-volume alkaline magmas. Surface outgassing CO2 from basalts may average up 3,000 Mt per year during LIP emplacement subsidized by fractionating magmas deep in crust. The quantities carbon mobilized LIPs be sourced convecting mantle, lithospheric mantle relative significance...

Significance Carbon outgassing from Large Igneous Provinces has been invoked as a mechanism to drive major climate shifts throughout Earth’s history. However, the lack of direct constraints on evolving carbon release magmas in these provinces represents challenge for understanding relationship between magmatism and environmental change. This paper presents CO 2 contents early Deccan Traps lavas based studies olivine-hosted melt inclusions. We use data evaluate links an episode pronounced...

The Toba eruption ∼74,000 y ago was the largest volcanic since start of Pleistocene and represents an important test case for understanding effects large explosive eruptions on climate ecosystems. However, magnitude repercussions climatic changes driven by are strongly debated. High-resolution paleoclimate archaeological records from Africa find little evidence disruption or human activity in wake contrast with a controversial link bottleneck evolution model simulations predicting strong...

The history of molecular oxygen (O2) in Earth's atmosphere is still debated; however, geological evidence supports at least two major episodes where O2 increased by an order magnitude or more: the Great Oxidation Event (GOE) and Neoproterozoic Event. concentrations have likely fluctuated (between 10-3 1.5 times present atmospheric level) since GOE ∼2.4 Gyr ago, resulting a time-varying ozone (O3) layer. Using three-dimensional chemistry-climate model, we simulate changes O3 consider...

Although Titan's surface shows clear evidence of erosional modification, such as fluvial incision, for tectonism has been less apparent. On Earth, networks with strongly preferred orientations are often associated structural features, faults or joints, that influence flow erodibility. We delineated and classified the morphologies drainages on Titan discovered control. Fluvial were both synthetic aperture radar (SAR) images covering ∼40% from Cassini Radar Mapper up through T71 visible light...

River systems reveal planetary tectonics Earth, Mars, and Titan have all hosted rivers at some point in their histories. Rivers erode the landscape, leaving behind signatures that depend on whether surface topography was place before, during, or after period of liquid flow. Black et al. developed two metrics to measure how well river channels align with surrounding large-scale (see Perspective by Burr). Earth's plate introduce features such as mountain ranges cause divert, processes clearly...

Drainage networks on Titan, Earth, and Mars provide the only known examples of non‐volcanic fluvial activity in our solar system. The drainage Titan are apparently result a methane‐ethane cycle similar to Earth's water cycle. scarcity impact craters uneven distribution dissection suggest that surface may be relatively young. purpose this study is assess importance erosion relative other plausible mechanisms resurfacing such as tectonic deformation, cryovolcanism, or deposition aerosols. We...

Abstract The Permian-Triassic extinction was the most severe in Earth history. Siberian Traps eruptions are strongly implicated global atmospheric changes that likely drove extinction. A sharp negative carbon isotope excursion coincides within geochronological uncertainty with oldest dated rocks from Norilsk section of flood basalts. We focused on voluminous volcaniclastic Traps, relatively unstudied as potential carriers carbon-bearing gases. Over six field seasons we collected across...

Parameter sharing, where each agent independently learns a policy with fully shared parameters between all policies, is popular baseline method for multi-agent deep reinforcement learning. Unfortunately, since agents share the same network, they cannot learn different policies or tasks. This issue has been circumvented experimentally by adding an agent-specific indicator signal to observations, which we term "agent indication". Agent indication limited, however, in that without modification...

Research Article| May 01, 2015 Campanian Ignimbrite volcanism, climate, and the final decline of Neanderthals Benjamin A. Black; Black * 1Department Earth Planetary Science, University California–Berkeley, Berkeley, California 94720, USA *E-mail: bblack@berkeley.edu Search for other works by this author on: GSW Google Scholar Ryan R. Neely; Neely 2National Centre Atmospheric Leeds, Leeds LS2 9JT, UK3Institute Climate School Environment, UK4Advanced Study Program, National Center (NCAR),...

Abstract Most of the Martian crust formed prior to ∼4 Ga, but magmatic processes responsible for finalizing structure and composition ancient remain enigmatic. Impacts can produce large volumes melt under a wide range melting pressures, temperatures, degrees melting. Hellas, Argyre, Isidis, Utopia basins date around 4 demonstrating that basin‐scale impacts helped place finishing touches on an already established crust. In this work, we focus ascent intrusion impact partial melts generated at...

Abstract Magnetic and geologic data indicate that the ratio of intrusive to extrusive magmatism (the I / E ratio) is higher in Tharsis Syrtis Major volcanic provinces on Mars relative most centers Earth. The fraction magmas erupt helps determine effects crustal structure flux magmatic gases atmosphere also influences estimates melt production inferred from history surface volcanism. We consider several possible controls prevalence at Major, including rates, lithospheric properties, regional...

Annual growth increments formed in bivalve shells are increasingly used as proxies of environmental variability and change marine ecosystems, especially at higher latitudes. Here, we document that well-replicated exactly dated chronologies can also be developed to capture oceanographic processes temperate semi-enclosed seas, such the Mediterranean. A chronology is constructed for Glycymeris pilosa from a shallow embayment northern Adriatic extends 1979 2016. The significantly (p < 0.05)...

Abstract The Earth's surface volcanism exerts first‐order controls on the composition of atmosphere and climate. On Earth, majority occurs at mid‐ocean ridges. In this study, based dependence melt fraction temperature, pressure, composition, we compute production degassing rate ridges from three‐dimensional global mantle convection models with plate motion history as velocity boundary condition. By incorporating melting in models, connect deep to volcanism, shallow processes internally...

We infer Amazonian climate change events from the presence of fresh craters with excess volumes ejecta. Using Mars Orbiter Laser Altimeter data, geometrical properties 572 impact rim diameters between 2.5 and 102 km were compiled in lowland highland plains. The data reveal a class anomalously high ejecta preferentially located Utopia Planitia. These fresh, “excess ejecta” have material above preimpact surface larger than crater cavity by factors to 5.8. volume corresponds an thickness about...