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19 December 2014
Rocks: the larger they are, the faster they crumble
Sooner or later, mountains crumble into boulders, boulders crumble into rocks and pebbles, and so on, until wind and rivers carry sand and dust into the ocean, completing the geologic rock cycle. “But how [rocks] go from the mountain into that ocean bottom, that’s what is not understood very well,” said Jaakko Putkonen, a geologist with the University of North Dakota. Scientists from UND and other institutions discovered that chunks of rock break off of boulders in Antarctica once every 1,900 years on average, and those smaller chunks break apart once every 510,000 years. Putkonen thinks that heat flow through rocks might be responsible for the dramatic difference in how fast bigger rocks crumble compared to smaller rocks. Knowing how fast boulders break down into smaller and smaller chunks will help geologists understand how the mountains crumble to the sea everywhere.
Quality control of aerosol measurements filters out important readings
The hardworking AERONET (AErosol RObotic NETwork) instrument in Baengyeong, South Korea was having a rough day. Every 15 minutes, the telescope-like device pointed its barrel at the sun to record its light and measure how much was blocked by airborne particles, or aerosols. July 13, 2012 was an overcast day and the light absorbed by the clouds dominated the measurements. But then, just after 1 p.m., the clouds parted, the instrument looked up, and data was collected. Only no one saw it.
18 December 2014
Heaven Above and Earth Below: Scientists Track Atmospheric Disturbances to Gather Earthquake Data
Earthquakes generate seismic waves that propagate through earth, water, and air. Generations of geologists have used ground-based seismometers to decipher information about earthquakes, including magnitude, epicenter, depth and tsunami danger. But more recently some researchers have wondered if seismic waves traveling through the air also carry traceable information about the earthquake that generated them. If so, measuring seismic waves in the atmosphere could potentially speed up earthquake reporting systems and improve the accuracy of tsunami alerts.
Tracking wastewater in the ocean with satellites
Scientists can use satellites to track wastewater plumes in the ocean, according to new research presented Tuesday afternoon at the American Geophysical Union Fall Meeting in San Francisco. Researchers from NASA Jet Propulsion Laboratory and other research institutions tracked wastewater plumes from the Los Angeles County and Orange County treatment plants in California during maintenance in 2006 and 2012, respectively. Each plant temporarily diverted wastewater into an older, shorter, shallower pipe. But treated sewage still contains contaminants, so each plant also conducted expensive ocean monitoring.
Heart Rate Monitors for Shellfish May Help Purify Rivers
In tanks at the University of Iowa, mussels equipped with heart rate monitors are purifying water with their excrement. Like human heart monitors, the gadgets glued to the mussels’ shells provide information about activity and metabolism. But in the mussels’ case, this information is helping researchers understand how mussels cleanse the water of agricultural runoff.
Lightning Bolts May have Jolted Life on Earth
Michael Wong wants to understand how life could evolve on other worlds. A graduate student in planetary sciences at the California Institute of Technology, he usually focuses on planetary atmospheres. But recently, his quest took Wong to a strange, hostile setting: the bottom of an acidic ocean on Earth, 4 billion years ago.
17 December 2014
New computer system predicts malaria outbreaks in Ethiopia
Scientists have created a computer system that will help predict malaria outbreaks in northwestern Ethiopia. The advance warning system, which uses local epidemiological information and real-time environmental data, will allow public health officials to transport resources to high-risk areas and contain outbreaks early, explained ecologist Chris Merkord from South Dakota State University.
Unmarked burial sites: where history and geophysics team up
Located about 25 miles north of Houston, Mueschke Cemetery is a historical burial ground. With its oldest headstone dating back to 1849, the cemetery is the resting place for close to 150 people, many of them soldiers killed in 150 years of American wars. But the cemetery is also known to contain dozens of unmarked graves, their locations lost over time. Now, a tool used by geologists and engineers is helping to find them: radar.
New evidence for a massive flood on the Mackenzie River 13,000 years ago
The Northern Hemisphere suddenly cooled about 12,800 years ago in an event named the Younger Dryas. Scientists have debated the cause for many years. One widely-believed explanation is that the massive but long gone Lake Agassiz in central Canada rapidly flooded fresh water east down the St. Lawrence River into the northern Atlantic Ocean. That pulse of fresh water interfered with warm ocean currents and triggered the cooling.
An updated geological timeline for the extinction of the dinosaurs
The asteroid that smashed into the Yucatan Peninsula a little more than 66 million years ago left behind the Chicxulub crater, but it also left behind something else: iridium, a rare element, which settled in a fine layer all over the world. When scientists discovered this layer between rock strata in the 1980s, it eventually led them to the crater as well, and an explanation for the disappearance of the dinosaurs. But on either side of that layer, which serves as a geological boundary between the Cretaceous and the Paleogene, determining the age of rock is more difficult. This fuzziness makes it harder for paleontologists to piece together the timeline of life’s evolution after the mass extinction, which included the emergence of humans and all other mammals.
GeoSpace is a blog on Earth and space science, managed by AGU’s Public Information staff. The blog features posts by AGU writers and guest contributors on all sorts of relevant science topics, but with a focus on new research and geo and space sciences-related stories that are currently in the news.