Taxonomy term

may 2017

Benchmarks: June 1977: First Excavations at Nebraska's Ashfall Fossil Beds

In the spring of 1971, paleontologist Mike Voorhies was mapping rock exposures on a farm in northeastern Nebraska when he wandered into a small ravine that recent heavy rains had swept clean of debris. High on the gully wall, a change in the color of the rock caught his eye, so he decided to scramble up and take a closer look.

 
31 May 2017

Ups and downs of potassium feldspar may play role in clouds and climate

For water vapor in the atmosphere to transform into icy, cloud-forming droplets, it needs a seed around which to condense, such as aerosols, sea salt or bacteria. One of the most effective seeds is mineral dust, in particular potassium feldspar, one of the main ingredients in granite. New research tracking fluxes of potassium feldspar in the atmosphere through geologic time is shedding light on the long-term importance of the mineral in cloud formation and climate feedback cycles.

30 May 2017

1883 sea rescue informs new model of wind-wave interactions

Despite improvements in oceanographic observation, knowledge gaps remain about the interactions between ocean waves and wind blowing over the water’s surface. This is in part due to the difficulty of observing the ocean in high seas and windy conditions. In a new study in Geophysical Research Letters, however, researchers have used a historical record of a treacherous 1883 at-sea rescue — aided by the wave-calming effects of a fish-oil slick — to develop a model of how wind and water interact to form different sizes and types of waves.

29 May 2017

Down to Earth With: Biogeochemist Stephen MacAvoy

Stephen Mac­Avoy is an associate professor and chair of the environmental science department at American University in Washington, D.C. MacAvoy specializes in the urban environment found in his own backyard, studying urban water problems like stormwater overflow, which contributes to sewage and nutrient pollution, and the geochemistry of the degraded Anacostia River. He recently spoke with EARTH about how living “green” roofs can help reduce pollution in waterways, his surprising love of teaching and his advice for young scientists.

26 May 2017

Timing of famed "Millennium Eruption" pinpointed

Changbaishan Volcano in northeastern China, on the border with North Korea (where it’s known as Mount Paektu), is steeped in superstition, having produced devastating eruptions several times in recorded history. Legends that a massive eruption in the 10th century led to the downfall of a regional empire have now been refuted, however, thanks to a new analysis of a fossilized tree killed by the eruption that dates the eruption to after the kingdom fell.

25 May 2017

Geologic Column: Is it aged or mature?

The authors cast a poetic eye on the language used to discuss aging in geoscience and engineering.
24 May 2017

Horned dinosaur find a first for eastern North America

Fossils of horned dinosaurs called ceratopsids, the group that includes Triceratops, are usually found in either western North America or Asia. But the discovery of a single ceratopsid tooth in Mississippi, reported in a new study in PeerJ, hints that this group spread into new territory at the tail end of the Mesozoic Era — just prior to going extinct.

23 May 2017

Benchmarks: May 23, 1967: Space weather forecasters avert war

In spring 1967, international political tensions were high. The United States and the Soviet Union were engaged in the space race, as well as a nuclear arms race. The Cuban Missile Crisis, less than five years earlier, was still fresh in people’s minds. The war in Vietnam was escalating, as was the U.S. antiwar movement at home. And in the Middle East, Israel and its neighbors were on the precipice of the Six Day War.

23 May 2017

Meteorites did not spark Ordovician biodiversification

During the Ordovician Period, roughly 470 million years ago, an asteroid the size of a small moon collided with another rocky object in the belt between Mars and Jupiter, shattering the asteroid into billions of pieces. Fragments from the epic collision still occasionally fall to Earth today, making up a large share of the meteorites recovered. But in the immediate wake of the Ordovician event, many pieces rained down on the planet, settling on the surface and in layers of rock forming at the time. In a new study, researchers studying some of these meteorite-rich layers have refined the timescale for the collision. The results bring into question a proposed link between the meteorite bombardment and an evolutionary uptick known as the Great Ordovician Biodiversification Event (GOBE).

23 May 2017

When and how did plate tectonics begin on Earth?

Earth’s surface is a shifting puzzle of plates that collide and diverge, generating earthquakes, fueling volcanoes, opening ocean basins and raising mountain ranges. But when and how did this process — unique in our solar system as far as we know — begin? 
22 May 2017

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