Geology

Magma sitting 4-5 kilometers beneath the surface of Oregon's Mount Hood has been stored in near-solid conditions for thousands of years but that doesn't mean it won't change rapidly. 

The time it takes to liquefy and potentially erupt is surprisingly short - perhaps as short as a few months.

The key seems to be elevation of the temperature of the rock to more than 750 degrees Celsius, which can happen when hot magma from deep within the Earth's crust rises to the surface. 

It was the mixing of hot liquid lava with cooler solid magma that triggered Mount Hood's last two eruptions about 220 and 1,500 years ago, said Adam Kent, an Oregon State University (OSU) geologist and co-author of a paper reporting the new findings.


Zircon crystals from Western Australia's Jack Hills region crystallized 4.4 billion years ago, building on earlier studies that used lead isotopes to date Australian zircons and identify them as the oldest bits of the Earth's crust. The microscopic zircon crystal is now confirmed to be the oldest known material of any kind formed on Earth. 

A new study strengthens the theory of a "cool early Earth," where temperatures were low enough for liquid water, oceans and a hydrosphere not long after the planet's crust congealed from a sea of molten rock. The study reinforces the belief that Earth had a hydrosphere before 4.3 billion years ago and possibly life not long afte.


The U.S. Geological Survey has gone cosmic and produced the first global geological map of Ganymede, Jupiter's largest moon and the largest in the solar system.


Earth's largest mass extinction occurred some 252 million years ago, wiping out more than 96 percent of marine species and 70 percent of life on land, including the largest insects known to have inhabited the Earth. Multiple hypotheses have tried to determine the cause of what's now known as the end-Permian extinction, including everything from an asteroid impact to massive volcanic eruptions and a cataclysmic cascade of environmental events.


Lorena Moscardelli of Statoil North America–Research, Development and Innovation in Austin is not the first to claim evidence to support the existence of a Martian ocean during the late Hesperian–early Amazonian. Viking Orbiter images did that throughout the 1980s and early 1990s.

Others have based their beliefs on alleged paleoshorelines, which has been heavily contested due to large variations in elevation (and some turned out to be of volcanic origin), but Moscardelli uses a new terrestrial, deep-water analogy. 


In a way, you could be walking on water right now.

Water is carried to the mantle by deep sea fault zones which penetrate the oceanic plate as it bends into the subduction zone. Subduction, where an oceanic tectonic plate is forced beneath another plate, causes large earthquakes such as the recent Tohoku earthquake, as well as many earthquakes that occur hundreds of kilometers below the Earth's surface.

Over the age of the Earth, the Japan subduction zone alone could transport the equivalent of up to three and a half times the water of all the Earth's oceans to its mantle, according to a new paper which shows that deep sea fault zones could transport much larger amounts of water from the Earth's oceans to the upper mantle than previously thought. 


Relic moss samples exposed by modern Arctic warming have been found to date as far back as 44,000 years ago, according to radiocarbon dating. 


Seismic waves penetrating to a depth of almost 200 miles report the discovery of an anomaly that likely is the volcanic mantle plume of the Galapagos Islands - it's just not where geologists and computer modeling had assumed.


Researchers have determined the isotope composition of the rare trace elements Hafnium and Neodymium in 2.7 billion year-old seawater using high purity chemical sediments from Temagami Banded Iron Formation (Canada) and concluded that large landmasses must have existed then.

The Temagami Banded Iron Formation was formed 2.7 billion years ago during the Neoarchean period and can be used as an archive because the isotopic composition of many chemical elements such as Hafnium and Neodymium directly mirrors the composition of Neoarchean seawater. These two very rare elements allow many valuable conclusions about weathering processes to be drawn. Earlier work has shown that these Canadian rocks only contain chemical elements that directly precipitated from ocean water.


The April 10th, 2013 landslide at a Utah copper mine probably was the biggest non-volcanic slide in North America's modern history, and included two rock avalanches that happened 90 minutes apart and surprisingly triggered 16 small earthquakes, according to findings published in
GSA Today.

The landslide moved at an average of almost 70 mph, reached estimated speeds of at least 100 mph and left a deposit so large it "would cover New York's Central Park with about 20 meters (66 feet) of debris," according to the researchers.