Blog Profile / GeoScienceWorld


URL :http://geoscienceworld.org/
Filed Under:Academics / Geology
Posts on Regator:187
Posts / Week:6.4
Archived Since:September 5, 2016

Blog Post Archive

A previously unrecognized high-temperature impactite from the Steen River impact structure, Alberta, Canada

Here, we report a previously unrecognized impactite from the Steen River impact structure in Alberta, Canada, which was intersected by continuous diamond drill core into the allochthonous proximal deposits of this buried 25-km-diameter complex crater. Show More Summary

Recurrent hierarchical patterns and the fractal distribution of fossil localities

Understanding the spatial structure of fossil localities is critical for interpreting Earth system processes based on their geographic distribution. Coordinates of marine and terrestrial sites in the conterminous United States for 17 time bins were analyzed using point pattern statistics. Show More Summary

Seismic array constraints on reach-scale bedload transport

Measurements and mechanical models of heterogeneous bedload transport in rivers remain basic challenges for studies of landscape evolution and watershed management. A 700 m reach of the Trinity River (northern California, USA), a large...Show More Summary

The control of the tropical North Atlantic on Holocene millennial climate oscillations

Changes in ocean dynamics in the northern North Atlantic affect the thermohaline circulation that controls global climate. During glacial and deglaciation periods these dynamics are enhanced due to large variations in the surface ocean density caused by changes in glacier volumes. Show More Summary

Controls and feedbacks in the coupling of mountain channels and hillslopes

Mountain channels can be strongly coupled with adjacent hillslopes, exchanging both mass and energy. However, hypotheses of the underlying cause and effect relations are based on indirect observations that do not resolve the mechanics of channel-hillslope coupling at the process scale. Show More Summary

Block-controlled hillslope form and persistence of topography in rocky landscapes

Rocky hillslopes dotted with boulder-sized blocks and covered by a thin, nonuniform soil are common in both steep landscapes and arid environments on Earth, as well as on other planets. While the evolution of soil-mantled, convex-upward...Show More Summary

Pore fluids in Dead Sea sediment core reveal linear response of lake chemistry to global climate changes

Pore fluids extracted from a 456 m sediment core, recovered within the framework of a multinational and International Continental Scientific Drilling Program (ICDP) co-sponsored effort at the bottom of the terminal Dead Sea, recorded the chemical variations in the deep lake over the past 220 k.y. Show More Summary

Aragonitic scleractinian corals in the Cretaceous calcitic sea

Changes in seawater chemistry have affected the evolution of calcifying marine organisms, including their skeletal polymorph (calcite versus aragonite), which is believed to have been strongly influenced by the Mg/Ca ratio at the time these animals first emerged. Show More Summary

Sediment cycling on continental and oceanic crust

Sedimentary rocks are often described as declining in quantity with increasing age due to the cumulative effects of crustal deformation and erosion. One important implication of such a model is that the geological record becomes progressively less voluminous and less complete with increasing age. Show More Summary

How to make a 350-m-thick lowstand systems tract in 17,000 years: The Late Pleistocene Po River (Italy) lowstand wedge

The 350-m-thick succession of the Po River lowstand wedge (Italy) associated with the Last Glacial Maximum (deposited over ~17 k.y) contains stratal architecture at a physical scale commonly attributed to much longer time scales, with complex, systematically varying internal clinothem characteristics. Show More Summary

Events, episodes, and phases: Signal from noise in flood-sediment archives

Major floods have increased in frequency in many parts of the world, and this is often attributed to anthropogenic climate change. Because of the short length of most gauged records (~50 yr), it is unclear whether these events represent a short-term anomaly or a shift to a prolonged flood-rich period. Show More Summary

Past changes in the North Atlantic storm track driven by insolation and sea-ice forcing

Changes in the location of Northern Hemisphere storm tracks may cause significant societal and economic impacts under future climate change, but projections of future changes are highly uncertain and drivers of long-term changes are poorly understood. Show More Summary

Dating Icelandic glacial floods using a new viscous remanent magnetization protocol

A new protocol using the viscous remanent magnetization (VRM) of boulders to date cataclysmic geological events such as tsunamis, glacial floods, and landslides is presented and its performance is assessed against two jo?kulhlaups (glacial floods) of known age in Iceland. Show More Summary

Zinc isotope evidence for intensive magmatism immediately before the end-Permian mass extinction

The end-Permian extinction is typically ascribed to massive volcanic eruptions, but direct geochemical evidence linking the two independent events is generally lacking. Zinc is an important micronutrient of marine phytoplanktons, and Zn isotope ( 66 Zn) ratios of seawater are markedly higher than those of volcanic rocks and riverine waters. Show More Summary

The overlooked human influence in historic and prehistoric floods in the European Alps

Understanding the role of climate and humans in generating mountain slope instability is crucial because such instability influences downstream fluvial activity and is a major threat to societies. Here, we use the sedimentary archive...Show More Summary

Isotopic signature of dissolved iron delivered to the Southern Ocean from hydrothermal vents in the East Scotia Sea

It has recently been demonstrated that hydrothermal vents are an important source of dissolved Fe (dFe) to the Southern Ocean. The isotopic composition ( 56 Fe) of dFe in vent fluids appears to be distinct from other sources of dFe to the deep ocean, but the evolution of 56 Fe during mixing between vent fluids and seawater is poorly constrained. Show More Summary

Widespread compression associated with Eocene Tonga-Kermadec subduction initiation

Eocene onset of subduction in the western Pacific was accompanied by a global reorganization of tectonic plates and a change in Pacific plate motion relative to hotspots during the period 52–43 Ma. We present seismic-reflection and rock...Show More Summary

Long-term glacier melt fluctuations over the past 2500 yr in monsoonal High Asia revealed by radiocarbon-dated lacustrine pollen concentrates

Long-term records of glacier mass changes are important for improving our understanding of glacier dynamics and for predicting the response of glaciers to future climate change. In contrast to moraine sequences that only record isolated stages of glacier status, proglacial lake sediments may record long-term continuous glacier activities. Show More Summary

Stratigraphic unmixing reveals repeated hypoxia events over the past 500 yr in the northern Adriatic Sea

In the northern Adriatic Sea and in most semienclosed coastal regions worldwide, hypoxia induced by eutrophication in the late 20 th century caused major die-offs of coastal marine organisms. However, ecosystem responses to hypoxia over...Show More Summary

A new model for turbidity current behavior based on integration of flow monitoring and precision coring in a submarine canyon

Submarine turbidity currents create some of the largest sediment accumulations on Earth, yet there are few direct measurements of these flows. Instead, most of our understanding of turbidity currents results from analyzing their deposits in the sedimentary record. Show More Summary

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