Taxonomy term

desert

Travels in Geology: Cones and craters in Flagstaff, Arizona

Few places in the country exhibit as many types of volcanic features — including jagged lava flows, crumbly cinder cones and the remnants of a towering stratovolcano — in as small an area as northern Arizona’s San Francisco Volcanic Field.
04 Oct 2017

Travels in Geology: Tracking African animals and deranged drainages across the Kalahari

The Okavango Delta, a major river delta in the middle of the dry Kalahari, and thundering Victoria Falls, a day’s drive away, may seem unrelated. But to a geologist, they are inextricably linked by hydrologic changes that have swept across southern Africa in response to subtle tectonic movements and major Pleistocene climate fluctuations.
12 Jun 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

Electric fields lift dust into the air at massive scales

During the Dust Bowl of the 1930s, black blizzards of dust enveloped the Great Plains, destroying crops. When farmers heard a crackling sound over the radio, they often knew a dust storm was coming, as such storms carry an electric field that can disrupt electronic equipment. Scientists have known since the 1800s that these fields exist, but how they might affect the swirling dust around them has not been understood. In airborne dust over the Sahara Desert, scientists have now directly measured these electric fields for the first time and found that, if strong enough, the fields can lift vast amounts of dust into the air.

25 Oct 2016

Down to Earth With: Ethnogeologist Steven Semken

As a boy growing up in New Jersey, Steven Semken was fascinated by rocks and minerals. His father, a banker, and his mother, a municipal tax collector, loved to travel and frequently indulged their son’s yen for sparkling specimens. They also bought Semken numerous books about geography and geology, including “The Big Golden Book of Geology,” which made such an impression that his childhood copy still sits on his office shelf. Semken vividly remembers staring at the book’s picture of Ship Rock, a towering volcanic neck on the Navajo Nation in northwestern New Mexico. Little did he know that he would later spend 15 years living and teaching geology with that Ship Rock as a backdrop.

06 May 2016

Travels in Geology: Touring Texas' Trans-Pecos

In far southwestern Texas, west of the Pecos River and bordering Mexico lies the Trans-Pecos region, a profoundly beautiful area with a rich cultural history and fascinating and diverse geology.
04 Aug 2015

Geologic Column: Lighting out for the territory

The author contemplates the history of westward expansion into arid lands and wonders if our unwise use of resources in places like the U.S. Southwest will eventually return the land "to the process of geology."

27 Feb 2015

Travels in Geology: Winter sun and tectonic tales in Tucson

Late last March, seeking warm sun and a verdant landscape after a cold, snowy Colorado winter, our family headed south during the spring school break to the lowest-elevation place we could easily drive to in a day or two: Tucson. Hosting Saguaro National Park, the Arizona-Sonora Desert Museum and the largest concentration of astronomical observatories in the country, Tucson has the grand vistas, great hikes and learning opportunities we wanted.
 

15 Sep 2014