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Study: Lightning a major factor in shaping mountains

Compass readings help trace the impact of electrical storms

Summit County Colorado monsoon season.

A bolt of lightning strikes near the Continental Divide, in Summit County, Colorado.

By Summit Voice

Geologists in South Africa say that lighting strikes are significant factor in shaping the summit areas of mountains, thereby shaping the evolution of mountain landscapes. Specifically, they found that many angular rock formations in the Drakensberg Mountains are caused by lightning blasts — and not necessarily by the melt-freeze cycle as commonly assumed. Continue reading

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Massive rockslide closes parts of Dinosaur Nat’l Monument

100-foot chunk of rock breaks off canyon wall

The large lighter-colored area indicates the extent of the rock slide above Jones Hole Creek as seen from the fish hatchery

The large lighter-colored area indicates the extent of the rock slide above Jones Hole Creek as seen from the fish hatchery in Dinosaur National Monument. Photo via NPS.

By Summit Voice

FRISCO — A rockslide has closed portions of Dinosaur National Monument, According to the National Park Service, the slide has resulted in the closure of NPS lands from the boundary of the monument and the U.S. Fish and Wildlife Service hatchery to Ely Creek.

The first rock slide was reported June 18, when a large slab of rock broke free from a cliff face just a short distance inside the monument boundary, less than .25 miles from the Jones Hole Fish Hatchery. One fisherman reported having to run from a boulder that landed in the stream not too far from his location. After receiving reports, park rangers checked the scene and did not see any further activity. Continue reading

Volcano study helps measure historic ice sheet thickness

UBC geologists examine pyroclastic deposits near summit of tephra cone on south side of Kima'Kho. Key attributes of these deposits established that they were deposited above the level of a surrounding englacial lake.

UBC geologists examine pyroclastic deposits near summit of tephra cone on south side of Kima’Kho. Key attributes of these deposits established that they were deposited above the level of a surrounding englacial lake. Photo courtesy UBC Science.

Ancient tuyas hold climate clues

By Summit Voice

FRISCO —In what must have been incredible displays of fire and ice, ancient volcanoes once erupted under massive glacial ice sheets, leaving deposits that could help paleoclimatologists unravel some ice age puzzles.

In a recent study, University of British Columbia researchers surveyed those deposits at the Kima’ Kho tuya, which erupted under an ice sheet about 1.8 million years ago. Their findings suggest that he ancient regional ice sheet through which the volcano erupted was twice as thick as previously estimated. Continue reading

Does climate affect volcanic activity?

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Mt. St. Helens erupts in 1980. Photo courtesy USGS.

New research suggests melting ice sheets could trigger more vulcanism

By Summit Voice

SUMMIT COUNTY — Melting ice sheets may trigger an increase in global volcanic activity, according to researchers with the GEOMAR Helmholtz Centre for Ocean Research (based in Kiel, Germany), and Harvard, who matched historic geological records of vulcanism with warm climate periods.

“In times of global warming, glaciers on the continents are melting relatively quickly. At the same time the sea level rises. The weight on the continents decreases, while the weight on the oceanic tectonic plates increases. Thus, the stress changes within in the earth to open more routes for ascending magma,” said GEOMAR’s Dr Mario Jegen. Continue reading

The Grand Canyon gets a new birthday

New geologic technique suggests the Grand Canyon is 60 million years older than previously thought

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There’s no better place to contemplate Earth’s geological mysteries than the rim of the Grand Canyon, which may be quite a bit older than scientists had thought. Photo by Leigh Wadden.

By Summit Voice

SUMMIT COUNTY — When you stand on the edge of the Grand Canyon, it becomes a little easier to visualize the almost unimaginably powerful forces that give Earth the shape we know today — and also to get a sense of how long some of those processes have been at work.

New research led by CU-Boulder assistant professor Rebecca Flowers suggests that the Grand Canyon may be 60 million years older than previously thought. An analysis of mineral grains from the bottom of the western Grand Canyon indicates it was largely carved out by about 70 million years ago — a time when dinosaurs were around and may have even peeked over the rim.

The scientists used a dating method that exploits the radioactive decay of uranium and thorium atoms to helium atoms in a phosphate mineral known as apatite, said Flowers, a faculty member in CU-Boulder’s geological sciences department. The technique may help researchers unravel other geological mysteries. Continue reading

Rogue waves, not tsunamis, move Aran Island rocks

Careful mapping, anecdotal evidence and radiocarbon-dated clams tell the true story

A view over the karst landscape on Inishmore, from Dún Aengus, an ancient stone fort. PHOTO VIA WIKIMEDIA COMMONS.

By Summit Voice

SUMMIT COUNTY — Seemingly made of sheer rock, the Aran Islands, off the coast of Ireland, look like they were built to withstand the stormy waters of the North Atlantic forever.

But new research suggests the sea has enough force to push ridges of giant boulders — some weighing as much as 78 tons — far inland from the edge of the imposing cliffs.

Many geologists had long speculated that only a tsunami could have enough force to rearrange the massive slabs of limestone. Armed with equations that model the forces generated by waves, some researchers concluded that no ordinary ocean waves could muster the force necessary to move the largest of the boulders this high above the ocean surface and so far inland. The math suggests the rocks in the ridges could only have been put there by a tsunami. Continue reading

Death Valley’s Ubehebe Crater could explode again

The Ubehebe crater field from the air. PHOTO COURTESY NATIONAL PARK SERVICE.

Conditions still ripe for massive steam-magma interactions

By Summit Voice

SUMMIT COUNTY —Along with heat exhaustion, flash floods, rock falls, rattlesnakes and scorpions, visitors to Death Valley may one day witness a phreatomagmatic explosion in Ubehebe Crater, one of many unusual geologic formations in the California national park.

Geologists recently took a close look at the crater, finding that it was formed more recently than previously thought, and that conditions for a sequel may exist today. Before the studies, geologists were vague on the age of the 600-foot deep crater, which formed when a rising plume of magma hit a pocket of underground water, creating an explosion. The most common estimate was about 6,000 years, based partly on Native American artifacts found under debris. Continue reading

Caribbean yields deepest-ever ‘black smoker’ vents

Hydrothermal 'black smoker' vents near the Cayman Islands may offer new clues to the dispersal of deep sea organisms. PHOTO COURTESY NOAA.

Research offers new clues to sea-floor formation, dispersal of deep-ocean organisms

By Summit Voice

SUMMIT COUNTY — British oceanographers and biologists say a group of volcanic vents on the Caribbean seafloor are the deepest discovered to-date, and another field of vents on a nearby submerged mountain suggests that so-called black smoker hydrothermal vents may be much more common than previously believed.

The vents — about three miles deep in a rift in the Cayman Trough, south of the Cayman Islands — may be hotter than 450 °C and are shooting a jet of mineral-laden water more than a kilometre into the ocean above.Despite extreme conditions, the vents are teeming with a new species of shrimp that has a light-sensing organ on its back.

Results of the 2010 expedition were reported this week in the scientific journal Nature Communications. The deep-sea research was led by marine geochemist Doug Connelly at the National Oceanography Centre in Southampton and marine biologist Jon Copley of the University of Southampton. Continue reading

Antarctica: Gamburtsev Mountains reveal their secrets

International research team traces geological history of ice-buried range, including previously undiscovered evidence of rifting

An international research team explores the geological history of the Gamburtsev Mountains, buried under two miles of ice in eastern Antarctica. IMAGE COURTESY NASA>

The combined US-UK- German-Canadian team and the British Antarctic Survey aerogeophysical platform after the AGAP flight trials performed at the McMurdo Station of the US National Science Foundation. IMAGE COURTESY BRITISH ANTARCTIC SURVEY.

By Summit Voice

SUMMIT COUNTY — A comprehensive study of a remote Antarctic mountain range buried by ice will help geologists understand how other mountain ranges form, and also fills in some of the missing pieces in the global tectonic puzzle, according to a team of scientists who found evidence of a vast tectonic rift beneath almost 10,000 feet of ice.

“It was very exciting and very difficult,” said Colorado-based U.S. Geological Survey researcher Dr. Carol Finn, co-author of the research being published this week in the journal Nature. “This was huge hole in the data sets,” she said, explaining that the history of the Gamburtsev Subglacial Mountains — buried beneath the vast East Antarctic Ice Sheet — shows that mountain-building can’t always be pinned to a single mountain-building event. Continue reading

Fiery deep sea volcano offers clues to Earth’s history

A double magma bubble, about 1 ½ feet across at its base, emerges from the vent that scientists named Hades at the West Mata submarine volcano. PHOTO COURTESY NOAA & THE NATIONAL SCIENCE FOUNDATION.

Researchers collect rare rock samples associated with subduction zone formation

By Summit Voice

SUMMIT COUNTY —Scientists who watched rock and molten lava explode from a deep sea volcano say they may have have seen a process mimicking the birth of a subduction zone, where the oceanic crust on one tectonic plate slides beneath another, producing abundant volcanism and contributing heat, gases and mineral-laden fluids to ocean waters.

The researchers collected sample of  boninite, a rare, chemically distinct lava that accompanies the formation of Earth’s subduction zones.

Nobody has ever collected fresh boninite and scientists never had the opportunity to monitor its eruption before, said Joseph Resing, University of Washington oceanographer and lead author of an online article on the findings in Nature Geoscience. Earth’s current subduction zones are continually evolving but most formed 5 million to 200 million years ago. Scientists have only been able to study boninite collected from long-dead, relic volcanos millions of years old. Continue reading

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