Taxonomy term

february 2018

Meteorite impacts may have kick-started ancient subduction

Earth in the Hadean Eon, between 4.56 billion and 4 billion years ago, was much too hot to support active plate tectonics as we know it today, where cold, established plates slowly march around Earth. Yet some evidence, including from tiny zircon crystals dating to the Hadean, has suggested that a form of plate tectonics was active by about 4.1 billion years ago — about a billion years before many researchers think modern plate tectonics started. The mechanisms that could have initiated and sustained early tectonics are unclear, but according to a new study, constant bombardment of early Earth by meteorites could have triggered temporary bursts of early tectonism.

22 Feb 2018

Coal formation nearly froze Earth

Burning coal releases carbon dioxide, which warms the planet when the gas escapes into the air. On the flip side, coal formation sequesters carbon dioxide removed from the atmosphere by plants, which contributes to global cooling as the planet’s greenhouse gas blanket thins. According to new research, so much carbon was removed from the atmosphere in the Carboniferous Period, when most of Earth’s coal reserves formed, that the planet became almost completely covered in ice.

21 Feb 2018

Greenland's growing deltas: Combining historical and modern imagery to decode change in a telltale Arctic landscape

Greenland’s 1.7-million-squarekilometer ice sheet is shrinking. But how much meltwater and sediment drains from the ice sheet through rivers? Researchers are studying the island’s deltas to find out, and are getting help from some longforgotten aerial photos taken by the Danish Air Force in the 1930s.
20 Feb 2018

Growing up saber-toothed: Strong from the start

During the Pleistocene, saber-toothed cats were formidable predators, with their massive canines and powerful front legs sporting razor-sharp claws. The bones of saber-toothed cats are thicker and more robust compared to those of other large cats, both modern and extinct. And previous studies of Smilodon have shown that their forelimbs in particular featured several adaptations, including thickened cortical bone, which would have increased strength, presumably useful in subduing ambushed prey.

19 Feb 2018

Did mud volcanoes set the stage for Burgess Shale fossils?

Canada’s Burgess Shale is famous for a wide array of exquisitely preserved 500-million-year-old fossils, which are found in a dozen localities in the Canadian Rockies. Linking all these localities today is a geologic feature called the Cathedral Escarpment, which formed in the Cambrian as a steep line of underwater cliffs where regular mudslides are thought to have gently buried a diversity of organisms, setting the stage for the prolific fossil beds. However, new mineralogical clues found at several of the fossil-rich sites suggest that mud volcanism may have also played a starring role in creating the Burgess Shale.

16 Feb 2018

Travels in Geology: Las Vegas: The scenery beyond the slots

Beyond the Strip lie southern Nevada’s craggy limestone peaks, colorful sandstone canyons, and enormous conservation areas that, despite the searing desert heat, harbor a tremendous diversity of plants and wildlife. From soaring summits and graceful bighorn sheep to prehistoric petroglyphs, this desert oasis has a lot to offer the geo-minded traveler.
14 Feb 2018

Getting There and Getting Around Las Vegas

McCarran International Airport is the main gateway for exploring Las Vegas and the surrounding area. Except for sights along the Strip, it’s necessary to rent a car to see the attractions described here. If you fly in, you can rent a vehicle at the airport or take a shuttle or taxi into the city and rent a car as needed. Although all of these sites are open year-round, the best times of year to visit are in the spring and fall. In winter, it’s not possible to hike high in the Spring Mountains due to snow, and in summer the valley heat can be stifling. There are currently no visitor facilities or infrastructure at Tule Springs National Monument, but you can catch a glimpse of the fossil beds near one of two National Park Service signs, one located at the intersection of Moccasin Road and Durango Drive, and the other where North Decatur Boulevard meets Horse Drive.

14 Feb 2018

Benchmarks: February 12, 1986: France and the U.K. sign the Treaty of Canterbury, paving the way for the Chunnel

Since the tunnel connecting Britain and France beneath the English Channel opened in 1994, more than 390 million people and 320 million metric tons of goods have made the 50-kilometer subterranean trip. The Channel Tunnel, or Chunnel, which is actually three separate tunnels — two for rail traffic and one for maintenance — thus plays a major part in the countries’ economies, as well as in the broader European economy. Beyond that distinction, it has been memorialized in popular TV, movies and literature. And in recent years, the tunnel has taken on literal and symbolic significance as a gateway amid flows of refugees from strife-ridden parts of the world and in debates over immigration policy. The Chunnel has become so firmly embedded in the regional infrastructure and culture during the past quarter century that it is difficult to imagine it not being there today.

12 Feb 2018

Geologic Column: Travels with Claudia: Rediscovering America

A husband and wife set out to rediscover some places they knew well in their youth, and some they had only read about in books. Along the way, they learned much about where this country has been, where it is, and where it’s going.
12 Feb 2018

Red Planet Roundup: February 2018

With two rovers patrolling the surface of Mars, six spacecraft orbiting above it, and scientists here on Earth studying the Red Planet from afar, new findings are announced often. Here are a few of the latest updates.

09 Feb 2018

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