Geology
A newly identified fault that runs under the Adriatic Sea is actively building more of the famously beautiful Dalmatian Islands and Dinaride Mountains of Croatia, according to a new research report.
Geologists had previously believed that the Dalmatian Islands and the Dinaride Mountains had stopped growing 20 to 30 million years ago. From a region northwest of Dubrovnik, the new fault runs northwest at least 200 km (124 miles) under the sea floor.
The Croatian coast and the 1,185 Dalmatian Islands are an increasing popular tourist destination. Dubrovnik, known as "the Pearl of the Adriatic…
"In 2002," write Zalasiewicz and colleagues, "Paul Crutzen, the Nobel Prize-winning chemist, suggested that we had left the Holocene and had entered a new epoch - the Anthropocene - because of the global environmental effects of increased human population and economic development."
The authors document a radical yet compelling case for the idea that the appearance of humans has so physically changed Earth that there is no organic justification for linking pre- and post-industrialized Earth within the same epoch (the Holocene).
They state that the global environmental change since the start…
The first evidence of a volcanic eruption from beneath Antarctica’s most rapidly changing ice sheet is reported this week in the journal Nature Geosciences. The volcano on the West Antarctic Ice Sheet erupted 2000 years ago (325BC) and remains active.
Using airborne ice-sounding radar, scientists from British Antarctic Survey (BAS) discovered a layer of ash produced by a ‘subglacial’ volcano. It extends across an area larger than Wales.
The volcano is located beneath the West Antarctic ice sheet in the Hudson Mountains at latitude 74.6°South, longitude 97°West. Volcanoes are an important…
The motion, formation, and recycling of Earth’s crust—commonly known as plate tectonics—have long been thought to be continuous processes but new research by geophysicists suggests that plate tectonic motions have occasionally stopped in Earth’s geologic history, and may do so again.
The findings could reshape our understanding of the history and evolution of the Earth’s crust and continents.
Synthesizing a wide range of observations and constructing a new theoretical model, researchers Paul Silver of the Carnegie Institution of Washington and Mark Behn of the Woods Hole Oceanographic…
Planetary scientists have puzzled for years over an apparent contradiction on Mars. Abundant evidence points to an early warm, wet climate on the red planet, but there’s no sign of the widespread carbonate rocks, such as limestone, that should have formed in such a climate.
Now, a detailed analysis in the Dec. 21 issue of Science by MIT’s Maria T. Zuber and Itay Halevy and Daniel P. Schrag of Harvard University provides a possible answer to the mystery. In addition to being warmed by a greenhouse effect caused by carbon dioxide in the atmosphere, as on Earth, the early Mars may have had the…
For more than a decade geoscientists have detected what amount to ultra-slow-motion earthquakes under Western Washington and British Columbia on a regular basis, about every 14 months. Such episodic tremor-and-slip events typically last two to three weeks and can release as much energy as a large earthquake, though they are not felt and cause no damage.
Now University of Washington researchers have found evidence that these slow-slip events are actually affected by the rise and fall of ocean tides.
"There has been some previous evidence of the tidal effect, but the detail is not as great as…
An enormous submarine landslide that disintegrated 60,000 years ago produced the longest flow of sand and mud yet documented on Earth. The massive submarine flow travelled 1,500 kilometres – the distance from London to Rome – before depositing its load.
Details of the landslide and consequent sediment flow are reported online today in Nature by Dr Peter Talling from the University of Bristol, with colleagues from the National Oceanography Centre in Southampton and several other institutions.
Dr Talling said: “The volume of sediment transported by this flow in the deep ocean is difficult to…
Loess sediments and their soils cover around one-tenth of the earth. In Europe, loess is a powdery product of glaciations during the Ice Age. During those cold periods, this very fine, light material was swept from bare regions on the edges of the glaciers and deposited in regions with denser vegetation.
Loess consists largely of quartz grains and lime. The very fine grains ensure good aeration, water storage and mineral levels. This means that soils derived from loess are very fertile, like the black earth of the Börde plains, but are also particularly susceptible to erosion. It is…
Yellowstone is North America’s largest volcanic field, produced by a “hotspot” – a gigantic plume of hot and molten rock – that begins at least 400 miles beneath Earth’s surface and rises to 30 miles underground, where it widens to about 300 miles across. There, blobs of magma or molten rock occasionally break off from the top of the plume, and rise farther, resupplying the magma chamber beneath the Yellowstone caldera.
The Yellowstone “supervolcano” rose at a record rate since mid-2004, likely because a Los Angeles-sized, pancake-shaped blob of molten rock was injected 6 miles beneath the…
Seismologists in recent years have recast their understanding of the inner workings of Earth from a relatively benign homogeneous environment to one that is highly dynamic and chemically diverse. This new view of Earth’s inner workings depicts the planet as a living organism where events that happen deep inside can affect what happens at its surface, like the rub and slip of tectonic plates and the rumble of the occasional volcano.
New research into these dynamic inner workings are now showing that Earth’s upper mantle (an area that extends down to 660 km) exhibits how far more than just…