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Update: Arizona Reservoir Volume Status Spring 2017

As we head into summer here is a quick look at the state of Arizona's reservoirs at the end of February 2017. It was a good winter for recharge and the smaller reservoirs are faring well. Not so much, the Colorado River's Lake Mead and Powell. Reservoir data courtesy of CLIMAS - Climate Assessment for the Southwest. Posted 5/15/2017

Trump Exe. Order could impact four AZ National Monuments

On 26 April 2017, President Trump signed an executive order requiring the Department of the Interior to review national monuments comprising more than 100,000 acres and created since 1996. This review involves 20 national monuments. Physiographic features of Vermilion Cliffs Natl. Show More Summary

Warming and increased aridity during the earliest Triassic in the Karoo Basin, South Africa

The Permian-Triassic (P-T) mass extinction is the largest extinction event of the Phanerozoic and has been causally related to eruption of the Siberian Traps (Siberia, Russia) through climatic and ecological effects of volcanically forced greenhouse gas emissions. Show More Summary

The rise and fall of stromatolites in shallow marine environments

Stromatolites are abundant in shallow marine sediments deposited before the evolution of animals, but in the modern ocean they are restricted to locations where the activity of animals is limited. Overall decline in the abundance ofShow More Summary

A 65 k.y. time series from sediment-hosted glasses reveals rapid transitions in ocean ridge magmas

Studies of ocean ridge magmatism have been hampered by the difficulty in constructing time-series data over more than a few thousand years. Sediment rapidly covers newly formed ocean crust, and older rocks, even when recovered from fault scarps, cannot be dated accurately. Show More Summary

Synconvergent exhumation of metamorphic core complexes in the northern North American Cordillera

Continental metamorphic core complexes of the northern North American Cordillera were exhumed during the early Paleogene while the Farallon–North American plate convergence rate remained high. Such convergent boundary conditions canShow More Summary

The fate of sediment, wood, and organic carbon eroded during an extreme flood, Colorado Front Range, USA

Identifying and quantifying the dominant processes of erosion and tracking the fate of sediment, wood, and carbon eroded during floods is important for understanding channel response to floods, downstream sediment and carbon loading, and the influence of extreme events on landscapes and the terrestrial carbon cycle. Show More Summary

Glendonites track methane seepage in Mesozoic polar seas

During the Phanerozoic, Earth has experienced a number of transient global warming events associated with major carbon cycle perturbations. Paradoxically, many of these extreme greenhouse episodes are preceded or followed by cold climate, perhaps even glacial conditions, as inferred from the occurrence of glendonites in high latitudes. Show More Summary

A common origin of carbonatite magmas

The more than 500 fossil Ca-carbonatite occurrences on Earth are at odds with the only active East African Rift carbonatite volcano, Oldoinyo Lengai (Tanzania), which produces Na-carbonatite magmas. The volcano’s recent major explosive...Show More Summary

Modification of river meandering by tropical deforestation

Tropical forests are the only forest biome to have experienced increased rates of forest loss during the past decade because of global demands for food and biofuels. The implications of such extensive forest clearing on the dynamicsShow More Summary

Cascadia subduction tremor muted by crustal faults

Deep, episodic slow slip on the Cascadia subduction megathrust of western North America is accompanied by low-frequency tremor in a zone of high fluid pressure between 30 and 40 km depth. Tremor density (tremor epicenters per squareShow More Summary

Mantle melt production during the 1.4 Ga Laurentian magmatic event: Isotopic constraints from Colorado Plateau mantle xenoliths

Plutons associated with a 1.4 Ga magmatic event intrude across southwestern Laurentia. The tectonic setting of this major magmatic province is poorly understood. Proposed melting models include anorogenic heating from the mantle, continental arc or transpressive orogeny, and anatexis from radiogenic heat buildup in thickened crust. Show More Summary

Modelling satellite-derived magma discharge to explain caldera collapse

Many effusive eruptions are characterized by effusion rates that decay exponentially with time, a trend which is generally ascribed to elastic relaxation of a deep magma chamber. Thermal emissions, detected by satellite during the A.D. Show More Summary

Timing of initial seafloor spreading in the Newfoundland-Iberia rift

Broad areas of subcontinental lithospheric mantle are commonly exposed along ocean-continent transition zones in magma-poor rifts and are thought to be exhumed along lithospheric-scale detachment faults during the final stages of rifting. Show More Summary

Paleozoic echinoderm hangovers: Waking up in the Triassic

Echinoderms are among the marine invertebrates that underwent the most severe losses at the end-Permian extinction. The prevailing paradigm claims an extreme bottleneck with only very few, if not single, holdovers ("hangovers" herein) sparking the post-Paleozoic radiation. Show More Summary

Microfossil measures of rapid sea-level rise: Timing of response of two microfossil groups to a sudden tidal-flooding experiment in Cascadia

Comparisons of pre-earthquake and post-earthquake microfossils in tidal sequences are accurate means to measure coastal subsidence during past subduction earthquakes, but the amount of subsidence is uncertain, because the response times of fossil taxa to coseismic relative sea-level (RSL) rise are unknown. Show More Summary

Subtropical climate conditions and mangrove growth in Arctic Siberia during the early Eocene

The early Eocene (ca. 56–47.8 Ma) was an interval of exceptional warmth with reduced pole-to-equator temperature gradients. Climate proxies indicate mean annual air temperatures (MATs) and sea-surface temperatures (SSTs) exceeding 8–18...Show More Summary

New age constraints on Aptian evaporites and carbonates from the South Atlantic: Implications for Oceanic Anoxic Event 1a

High-resolution carbon isotope ( 13 C) profiles from shallow- and deep-water carbonates in the South Atlantic (Campos and Santos Basins) are here correlated to stratigraphically well calibrated Tethyan sections, constraining the end of major evaporite deposition in the South Atlantic to the early Aptian Oceanic Anoxic Event (OAE) 1a interval. Show More Summary

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