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adityarup chakravorty

Reconstructing ancient oxidant levels and their climatic effects

Oxidants in the troposphere, such as ozone and hydroxyl radicals, influence the life spans of other atmospheric components, including pollutants and greenhouse gases like carbon monoxide and methane. But how the abundance of tropospheric oxidants varies as climate changes is poorly understood. Part of the challenge is that these oxidants are too reactive to be preserved in paleo-records, such as ice cores.

29 Aug 2017

Did Jurassic tectonics lead to supergiant oilfields?

More than 6 percent of global oil production comes from a single oilfield: the supergiant Ghawar oilfield in eastern Saudi Arabia, which produces more than 5 million barrels of crude oil every day. In a new study in GSA Today exploring the origins of this vast oilfield, researchers have found that extensive tectonic plate movements during the Middle and Late Jurassic may have created the conditions necessary for the formation of the Ghawar and several other oilfields across the Middle East.

01 May 2017

Tropical rainfall shifts resulted in greener Sahara

Six thousand years ago, the Sahara — today the world’s largest nonpolar desert, stretching over an area larger than the contiguous United States — was dotted with lakes and vegetation. Rock paintings from that time depict a much wetter landscape, and show elephants, hippos, antelope and many other animals living in the region.

21 Apr 2017

Broadening ocean current could carry less heat poleward with climate change

Some ocean currents, like the Agulhas Current in the southwestern Indian Ocean, act like giant air conditioners, moderating Earth’s climate by shuttling heat from the equator toward the poles. The Agulhas is one of the largest and fastest currents in the world: Flowing southwest along the east coast of Africa, it stretches almost 1,500 kilometers and transports about 70 million cubic meters of water every second toward the South Pole at peak speeds upward of 7 kilometers per hour.

21 Feb 2017

Small floods can carve big canyons

Through the early 20th century, geologists argued over how the giant canyons of the Channeled Scablands in Eastern Washington were formed. Ultimately, a theory proposed by J Harlen Bretz in the 1920s — that the canyons were carved by catastrophic, short-lived outbursts of floodwaters unleashed when natural dams holding back glacial lakes collapsed — was shown to be correct. Controversy still exists, though, about the size of these ancient floods.
 

03 Feb 2017

Active Japanese volcano due for large eruption?

In January 1914, Japan’s most active volcano, Sakurajima, erupted violently, covering the nearby city of Kagoshima in a layer of ash. The lava flows from this event filled the strait between the mainland and the island volcano, transforming it into a peninsula.

04 Jan 2017

Small-scale factors influence mantle flow under the seafloor

In December 2011, scientists and technicians aboard the research vessel Marcus G. Langseth dropped several ocean-bottom seismometers into the deep Pacific more than 1,900 kilometers southeast of Hawaii to measure seismic activity and electrical conductivity to a depth of about 300 kilometers below the seafloor. Now, these measurements are providing new insights into how the mantle flows and deforms below the rigid tectonic plates that make up Earth’s surface.

22 Nov 2016

Bubble accumulation could explain massive volcanic sulfur releases

The spectacular 1815 eruption of Indonesia’s Mount Tambora spewed large amounts of sulfur gases into the atmosphere, which formed fine sulfur-rich particles that blocked sunlight and lowered global temperatures by more than half a degree Celsius, causing famine and death on a global scale.

23 Aug 2016

Mantle convection makes Earth's crust bob

From the earthquake-prone Himalayas and Andes to the volcanically active “Ring of Fire” around the Pacific, the boundaries of Earth’s tectonic plates are often sites of considerable geologic activity. In contrast, the interiors of tectonic plates have been thought to be relatively rigid and quiet.

18 Aug 2016

Searching for the ancestors of meandering rivers

It might be difficult to imagine Earth devoid of vegetation, but for billions of years the sun shone, winds blew and rivers flowed on a planet without any plants.

21 Jun 2016

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