Latest Sedimentology Stories

2009-07-07 16:50:00

The Amazon River originated as a transcontinental river around 11 million years ago and took its present shape approximately 2.4 million years ago. These are the most significant results of a study on two boreholes drilled in proximity of the mouth of the Amazon River by Petrobras, the national oil company of Brazil. A team formed by the Institute for Biodiversity and Ecosystem Dynamics (IBED) of the University of Amsterdam, the University of Liverpool and Petrobras used this new oceanic...

2009-06-09 15:48:40

Despite the great difficulties in quantifying all the environmental and human factors that affect sediment discharge by rivers into the sea, a group of Catalan scientists has compiled data to describe and evaluate the solid sediment discharge from nine river basins in Catalonia "“ the Ter, Foix, Gaia, Bes³s, Llobregat, Francolí, Tordera, Muga, and Fluvia. "This was a slow job, with its fair share of difficulties", Miquel Canals, one of the authors of the study and...

2009-05-12 11:55:00

Sediments released by many of the world's largest river deltas to the global oceans have been changed drastically in the last 50 years, largely as a result of human activity, says a Texas A&M University researcher who emphasizes that the historical information that can be gathered from sediment cores collected in and around these large deltaic regions is critical for a better understanding of environmental changes in the 21st century.Thomas Bianchi, a professor in the Department of...

2009-04-27 05:55:00

Climate change is now threatening France's Aquitaine coast, which stretches north from the Spanish border to the Gironde River, causing erosion that is endangering coastal communities. In 2006 the European LIFE program identified 13 coastal communities as hotspots for erosion. "There is a lack of sand on the beaches, because of a period of warming -- climate change," says Cyril Mallet, of the French geology and mining research agency BRGM. Climate change means more erosion for the area,...

2009-04-21 13:50:00

Climate change is resulting in massive drying of some of the world's biggest rivers, according to a report released on Tuesday. Researchers led by Aiguo Dai of the National Center for Atmospheric Research (NCAR) in Boulder, Colorado found that rivers including the Yellow River in northern China, the Ganges in India, the Niger in West Africa, and the Colorado in the southwestern United States are in danger of losing water due to climate change. "Reduced runoff is increasing the pressure on...

2009-01-08 17:29:17

Pebbles that become part of clastic rocks in places like Arizona's Lower Antelope Canyon don't move with the wind but against it, a geosciences professor said. Rather than being pushed into formations, the pebbles, or clasts, have the loose sand around them removed by the wind, Andrew Leier of the University of Calgary said in the journal Geology. The sand removal causes scour-pits to form on the wind side of larger clasts, and the pebbles eventually fall toward the wind into the scours, he...

2009-01-07 11:25:00

At first, figuring out how pebble-sized rocks organize themselves in evenly-spaced patterns in sand seemed simple and even intuitive. But once Andrew Leier, an assistant geoscience professor at the U of C, started observing, he discovered that the most commonly held notions did not apply. And even more surprising, was that his findings revealed answers to NASA's questions about sediment transport and surface processes on Mars. Those results are published in this month's edition of Geology....

2008-12-24 11:28:40

The sand used in Seattle to protect motorists from icy streets is more dangerous to aquatic life than typical road salt, environmentalists say. With more than 6,000 tons of sand already dispersed on Seattle streets since last Thursday, environmentalists claim the alternative winter road solution can clog area waterways and damage its precarious food chain, The Seattle Times said Wednesday. In general, what my colleagues have found, and I have found, is that sand actually has a greater impact,...

2008-12-17 13:45:00

As scientists search for life on Mars, they should take a close look at rock varnish, according to a paper in the current issue of the "Journal of Geophysical Research." The paper describes how a research team led by Kimberly R. Kuhlman, of the Tucson-based Planetary Science Institute, found bacteria associated with rock varnish in an area where the surrounding soils were essentially devoid of life. The study suggests that rock varnish could provide a niche habitat for microbial life on Mars...

2008-12-09 19:33:09

Hurricane Ike reconfirmed one Texas researcher's idea: Interfering with Galveston Island's natural elevation hurts the island's sand dunes and marsh flora. Ike reconfirmed the basic idea I've had for several years, Rusty Feagin, ecosystem scientist with Texas AgriLife Research at Texas A&M University, said in a news release. The plants on sand dunes and in marshes build an island's elevation, so we shouldn't compromise that. When comparing pre- and post-Ike marshes, Feagin said he found...

Latest Sedimentology Reference Libraries

River Delta
2013-04-18 22:36:25

A river delta is a landform that is created at the mouth of a river, where the river flows into an ocean, estuary, lake, sea, or reservoir. These deltas are built from the deposition of the sediment that is carried by the river as the flow exit’s the mouth of the river. Over a long period of time, this deposition constructs the distinctive geographic pattern of a river delta. The creation of a delta is made up of three core forms: the bottomset, topset, and foreset/frontset. Bottomset...

2005-05-26 11:13:08

In geology, a conglomerate is a rock consisting of other stones that have been cemented together. Conglomerates are sedimentary rocks consisting of subangular clasts and are thus differentiated from breccias, which consist of angular clasts. Both conglomerates and breccias are characterized by clasts larger than sand (>2 mm). There are two varieties of conglomerate, defined by texture: paraconglomerates and orthoconglomerates. Paraconglomerates are one of two varieties of conglomerate...

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Word of the Day
  • A beast of burden; also, a beast in general.
'Jument' ultimately comes from the Latin 'jugum,' yoke.