All

geology

Getting there and getting around Kalahari

There are three gateway cities to the Kalahari, all of which are at least a day’s drive from the Okavango Delta. Although it’s the farthest (about 12 hours away), the O.R. Tambo International Airport (JNB) in Johannesburg, South Africa, is the region’s largest and often has the best airfares and car-rental rates. Two closer alternatives, each about an eight-hour drive away, are Botswana’s Sir Seretse Khama International Airport (GBE) in Gaborone and Namibia’s Hosea Kutako International Airport (WDH) in Windhoek. Maun (MUB) is Botswana’s primary tourist hub and the delta’s main service town. Most accommodations there provide a free minibus transfer from the airport.

12 Jun 2017

The mackerel year: Tambora changed how New England fished

The 1815 eruption of Indonesia’s Tambora Volcano led to a 1- to 1.5-degree-Celsius drop in the average global temperature, prompting 1816 to be called the “year without a summer.” New research analyzes weather data and historical records from New England to explain why, in the northeast U.S., 1816 was also called the “mackerel year.” As eruption-induced extreme weather triggered food scarcity in some areas, including a reduction in alewife numbers along the U.S. Atlantic coast, fishermen in the Gulf of Maine turned to mackerel fisheries farther offshore that had been neglected while more easily fished coastal and freshwater species were available.

06 Jun 2017

Comment: Kitchen counter geology: Bringing rock identification to a new audience

Teaching professionals in the natural stone industry to identify rock types proved a rewarding experience for both the students and the teacher.

05 Jun 2017

Monsoon shifts shaped early Chinese cultures

Rapid, climate-driven shifts in monsoon patterns may have shaped ancient Chinese societies, according to new research. And their history could be our future.

01 Jun 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

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

Pages