Geology

No one can draw a connection between meteorite impacts and massive volcanic activity but the one certain instance where it has been confirmed, at the Cretaceous-Tertiary boundary, was the catastrophic event thought to be responsible for the extinction of the dinosaurs 65 million years ago.  Scientists say they now know of a second example and they publish the research in the Journal of the Geological Society.   This new event, uncovered after the 17 km diameter Logoisk impact structure in Belarus was precisely dated, is thought to have taken place around 30 million years ago. The…

South America is the world’s most species-rich area and there have been many theories as to why, ranging from animals and plants accompanying the continent when it broke loose from Africa to variations in the extent of the rainforests over millions of years creating new species. A thesis from a Gothenburg University doctoral student proposes a different theory: that the formation of the Andes was a 'species pump' which spread animals and plants across the continent. Researcher Alexandre Antonelli, a doctoral student at Gothenburg University’s Department of Plant and Environmental Sciences has…

Asteroids are hunks of rock that orbit in the outer reaches of space.  Scientists have generally assumed that their small size limited the types of rock that could form in their crusts but two newly discovered meteorites have changed that.   The two meteorites were discovered during the Antarctic Search for Meteorites (ANSMET) 2006/2007 field season in a region of the Antarctic ice known as the Graves Nunatak icefield. The light-colored meteorites, designated GRA 06128 and GRA 06129, were immediately recognized as being different from previously known meteorites.  …

Abundant tiny particles of diamond dust exist in sediments dating to 12,900 years ago at six North American sites, adding strong evidence for Earth’s impact with a rare swarm of carbon-and-water-rich comets or carbonaceous chondrites, reports a nine-member scientific team. These nanodiamonds, which are produced under high-temperature, high-pressure conditions created by cosmic impacts and have been found in meteorites, are concentrated in similarly aged sediments at Murray Springs, Ariz., Bull Creek, Okla., Gainey, Mich., and Topper, S.C., as well as Lake Hind, Manitoba, and Chobot, Alberta,…

Researchers using a powerful instrument aboard NASA's Mars Reconnaissance Orbiter have found a long sought-after mineral on the Martian surface and, with it, unexpected clues to the Red Planet's watery past.  Surveying intact bedrock layers with the Compact Reconnaissance Imaging Spectrometer for Mars, or CRISM, scientists found carbonate minerals, indicating that Mars had neutral to alkaline water when the minerals formed at these locations more than 3.6 billion years ago. Carbonates, which on Earth include limestone and chalk, dissolve quickly in acid. Therefore, their survival until…

It was Christmas Eve, 1858 when “people who in the streets, on pathways and in the fields saw a magnificent ball of fire appear, which shone with a brilliant, blinding light and all the colors of the rainbow, obscured the light of the moon and descended majestically from the sky.”   This was the description of the meteorite that fell that evening, from a report commissioned by Rafael Martínez Fortún, of the town of Molina de Segura in Murcia, whose farm was struck by what is still the largest meteorite recovered in Spain.  Since 1863, it has been exhibited in the National Museum of…

It sounds like a B movie starring Adrienne Barbeau (oops, that's "Amazon Women In The Avacado Jungle Of Death") but this international team of researchers have instead been collecting imaging data on the Soufriere Hills Volcano in Montserrat to understand the internal structure of the volcano and how and when it erupts.  "Using land-based measurement, we can see that over the time periods when the magma is erupting, the ground surface deflates into a bowl of subsidence and when the magma is sealed underground, the ground surface inflates like a balloon," says Barry Voight, professor…

Over the last several years, scientists have built a very convincing case that Mars hosted water, at least early in its history. Recent observations from the Mars Phoenix lander and other spacecraft show that the planet still holds vast deposits of water as ice at its poles and in soil-covered glaciers in the mid-latitudes. What is less known is how much water occupied the red planet and what happened to it during its geological march to the present. Mostly, evidence has pointed to a period when clay-rich minerals were formed by water, followed by a drier time, when salt-rich, acidic water…

Venus Express has made the first detection of an atmospheric loss process on Venus's day-side. Last year, the spacecraft revealed that most of the lost atmosphere escapes from the night-side. Together, these discoveries bring planetary scientists closer to understanding what happened to the water on Venus, which is suspected to have once been as abundant as on Earth. The spacecraft's magnetometer instrument (MAG) detected the unmistakable signature of hydrogen gas being stripped from the day-side. “This is a process that was believed to be happening at Venus but this is the first time we…

The closer scientists look at Saturn's small moon Enceladus, the more they find evidence of an active world. The most recent flybys of Enceladus made by NASA's Cassini spacecraft have provided new signs of ongoing changes on and around the moon. The latest high-resolution images of Enceladus show signs that the south polar surface changes over time. Close views of the southern polar region, where jets of water vapor and icy particles spew from vents within the moon's distinctive "tiger stripe" fractures, provide surprising evidence of Earth-like tectonics. They yield new insight into what may…