May 2017 on EARTH Magazine

Horned dinosaur find a first for eastern North America

Tue, 23 May 2017 08:16:00 -0400

The ceratopsid tooth found recently in Mississippi is held next to the lower left law of a Triceratops from Montana. Credit: Jeremy Copley, Mississippi Museum of Natural Science

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.

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

Fri, 19 May 2017 11:51:19 -0400

The "Rhino Barn" at Nebraska's Ashfall Fossil Beds State Historical Park. Credit: University of Nebraska, Lincoln.

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.

Geologic Column: Is it aged or mature?

Fri, 19 May 2017 10:41:55 -0400

Credit: Behzad Amir-Faryar and Pashang Salehi.

The term “aging” is used and interpreted in a variety of ways depending on the realm in which it’s applied. For wine, Scotch and certain cheeses, aging is generally considered a good thing, whereas, for humans, it is not. In the geosciences and engineering, it can refer to changes in material strength or properties over time. But even in these fields, its use is inconsistent: “Aging” in sand is completely different from “aging” in concrete or asphalt, for example.

Down to Earth With: Biogeochemist Stephen MacAvoy

Fri, 19 May 2017 10:30:06 -0400

Biogeochemist Stephen MacAvoy is an assistant professor and chair of the environmental science department at American University in Washington, D.C. Credit: Stephen MacAvoy.

When Stephen MacAvoy was growing up in the suburbs of Connecticut, most of the animals he encountered were pets: dogs, cats or the occasional bird. But on his annual family trips to the coast of North Carolina, the beach provided a window into an alien world. He collected washed-up blue crabs, snails and other marine organisms, with their intriguing shapes, spines and intricate mouthparts. His mother, a nursing professor, and his father, a business consultant, even allowed MacAvoy to bring his field samples home in a cooler.

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

Wed, 17 May 2017 10:09:58 -0400

Potassium feldspar is one of the main mineral components of Yosemite's famous granite, giving it a pinkish hue. Credit: Mary Caperton Morton.

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.

Timing of famed "Millennium Eruption" pinpointed

Mon, 15 May 2017 21:04:20 -0400

A fossilized tree, killed by the Millennium Eruption of Changbaishan Volcano on the border between China and North Korea, has allowed scientists to pinpoint the date of the eruption. Credit: Clive Oppenheimer.

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.

1883 sea rescue informs new model of wind-wave interactions

Mon, 15 May 2017 20:49:00 -0400

The sailing ship Ouragan — depicted in "Les Meteores" by Margolle and Zurcher, 3rd edition, published in 1869 — labors at sea under hurricane conditions. Credit: NOAA Photo Library.

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.

When and how did plate tectonics begin on Earth?

Mon, 15 May 2017 20:36:52 -0400

Credit: K. Cantner, AGI.

The basic story of Earth’s formation is familiar to most anyone who has taken a geology course: About 4.6 billion years ago, Earth formed when a rocky nucleus accreted dust and debris left over from the formation of our sun.

Meteorites did not spark Ordovician biodiversification

Mon, 15 May 2017 15:08:48 -0400

Zircon crystals contain trace amounts of uranium and thorium, making them useful for radiometric dating. These highly magnified crystals are about the size of a grain of sand. Credit: Anders Lindskog.

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).

Are North Atlantic storm tracks shifting south?

Mon, 15 May 2017 15:04:50 -0400

Two sites studied by scientists — one in the Outer Hebrides of Scotland and one in northwestern Spain — capture records of moderate to large storms crossing the North Atlantic. Credit: K. Cantner, AGI.

As the Arctic warms, decreasing temperature differences between the Arctic and the lower latitudes may push North Atlantic storm systems south. The factors that influence storm tracks are complicated, however, and the accuracy of models predicting future storm tracks is uncertain. The results of a new study, in which researchers looked at changes in Atlantic storm tracks over the past 4,000 years, could improve the accuracy of predictive models and help Europe prepare for shifting storm patterns.

"Blob"-related warming contributed to Pacific Northwest ozone spike

Mon, 15 May 2017 15:00:06 -0400

In June 2015, tropospheric ozone levels measured at the observatory on Oregon's Mount Bachelor were more than 20 percent above the decadal average. Credit: Pao Baylon.

In June 2015, instruments on Oregon’s Mount Bachelor recorded mean ozone for the month at 56 parts per billion, more than 20 percent higher than the average level for the 11 years prior. Other stations around the West noted similarly high readings, puzzling scientists over the cause of the rise. In a new study in Geophysical Research Letters, researchers describe a confluence of meteorological conditions that appear to have driven the phenomenon.

How often should we expect volcanic ash clouds over Europe?

Mon, 15 May 2017 14:56:48 -0400

Ash clouds from Iceland's more than 30 active volcanoes, including Eyjafjallajökull (seen here), can pose a safety threat to air traffic across the North Atlantic and much of Europe. Credit: NASA Goddard Space Flight Center.

In 2010, an ash cloud from an eruption at Iceland’s Eyjafjallajökull Volcano led to the most disruptive shutdown of North Atlantic and European airspace in aviation history. Given the high level of activity of Iceland’s more than two dozen active volcanoes, how often are such events to be expected? A new study comparing volcanic ash records over the last 1,000 years suggests that fallout over Europe may be more common than previously anticipated.

Tibetan Plateau populated long before advent of agriculture

Mon, 15 May 2017 14:18:53 -0400

Due to the harsh living conditions of the Tibetan Plateau — which has an average elevation over 4,500 meters — archaeologists have long assumed that people didn’t live in the Himalayan high country until after the adoption of agriculture in this region of the world, about 3,600 years ago. But a new study of a trove of handprints and footprints found around a fossilized mud spring in Tibet is suggesting that people may have lived here as early as 13,000 years ago.

Bare Earth Elements: Tour brings hurricane hunting aircraft and expertise to the masses

Thu, 11 May 2017 10:33:41 -0400

Attendees at NOAA's Hurricane Awareness Tour stop at Ronald Reagan National Airport near Washington, D.C., on May 9 view the agency's King Air 350-CER, which is equipped with multiple cameras as well as lidar instrumentation to evaluate damage and aid in response efforts following storms. Credit: Timothy Oleson

With hurricane season officially getting under way on May 15 in the Eastern Pacific and June 1 in the Atlantic — and named tropical systems already having popped up on both sides of the country — NOAA has been busy this week publicizing National Hurricane Preparedness Week. The outreach effort aims to inform the public — especially those who live in areas prone to tropical storms — about what they can do in advance to prepare for potentially damaging and life-threatening storms. This year, the agency is simultaneously hosting its annual Hurricane Awareness Tour, a week-long traveling exhibition featuring meteorological and preparedness experts from the National Hurricane Center (NHC), the National Weather Service, the Federal Emergency Management Agency and other partner groups.

Silk Road routes may have followed the herds

Thu, 04 May 2017 09:42:16 -0400

A herder leads sheep through mountainous terrain in Uzbekistan. The routes established by ancient nomadic herders through the highlands of Central Asia may have paved the way for Silk Road paths, according to recent research. Credit: Michael Frachetti

The Silk Road — the ancient trade route that stretched thousands of kilometers from China to the Mediterranean — often calls to mind images of large camel caravans trekking for months across deserts and over mountains, carrying luxurious linens, spices and gems between distant lands. In reality, the “road” comprised a network of many shorter relays between neighboring areas, with goods often changing hands many times in cities, rural villages and even remote trading outposts. The webbed nature of the network has long complicated archaeological efforts to map exactly where and how the Silk Road developed. In a new study in Nature, researchers have illuminated likely routes of Silk Road travelers through a region of particularly challenging terrain — mountainous Central Asia — with the help of an innovative mapping method.

Where on Earth? - May 2017

Fri, 28 Apr 2017 09:51:49 -0400

Click to enlarge photo.

Clues for May 2017:

This arch, inside a wind-eroded cave, is a popular shot for photographers, who must squeeze in to take the picture.
The state park in which the arch and cave are located, founded in 1934, also contains 2,000-year-old petroglyphs — showing, among other things, hunters using atlatls — and hosts an annual competition in which participants compete using the ancient weapons.
The park lies in bright red Aztec Sandstone, deposited in the Jurassic, and the windswept cross-bedding of the former dunes can still be discerned in outcrops today.

An economic argument for reframing the geoscientist's role in disaster mitigation

Thu, 20 Apr 2017 11:19:54 -0400

In February 2017, the spillway for the Oroville Dam — the nation's highest dam — started to crumble, threatening about 200,000 people downstream, including people in Oroville, Calif., who were required to evacuate. The spray cloud from the spillway can be seen in the distance, as can the earthen dam to the right of the spillway. Credit: Kelly M. Grow/ California Department of Water Resources.

Natural disasters are viewed as moments, sometimes agonizingly drawn out, when Earth undergoes paroxysms in populated areas that result in fatalities and economic losses. As physical scientists who study natural disasters, geoscientists typically look at the problem from the front end: Our focus is mostly on prediction, forecasting and prevention. We don’t often weigh in on the long-term societal implications of whatever natural disaster we’re studying. But perhaps we should, or at the very least be conversant with how a social scientist, like an economist, might think about disasters. A more holistic view might help us do more good than studying the physical science of disasters alone.

Geomedia: Film: 'Written on Water': A Modern Tale of a Dry West

Thu, 20 Apr 2017 11:12:57 -0400

Filmmaker Merri Lisa Trigilio. Credit: Merri Lisa Trigilio.

An endless patchwork of circular fields surrounds the small West Texas town of Olton. The unnatural shapes and sharp boundaries of the brown and green fields result from center-pivot irrigation systems that pull water from the Ogallala Aquifer and allow more crops to grow than the semi-arid landscape would otherwise allow. On these dusty farms and within town offices a drama is unfolding over what to do as irrigation wells run dry.

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

Thu, 20 Apr 2017 10:13:55 -0400

The sun, on May 23, 1967, shown in a narrow visible wavelength of light called Hydrogen-alpha. The bright region (center, top) is where the May 1967 storm originated. Credit: National Solar Observatory historical archive.

By Sara Pratt

Geologic Column: My China syndrome

Thu, 20 Apr 2017 10:01:05 -0400

Satellite photo of the Sichuan Basin — in Sichuan Province, north-central China. The pollution from the urban and industrial centers of the Sichuan Basin in Sichuan is visible at the bottom of the image. Credit: NASA, public domain.

My obsession with China began when our son Jeffrey moved there 10 years ago. Since then, we have visited him a half dozen times, and the change that we have witnessed in the country in that time has been staggering.

Down to Earth With: Paleontologist Gerta Keller

Thu, 20 Apr 2017 09:55:52 -0400

Gerta Keller looks at sediment samples along the Brazos River in Texas. Credit: Gerta Keller/courtesy of NSF.

The mass extinction that did in the dinosaurs is one of the best-known events in geology. It’s also one of the most contentious.

Ice (Re)Cap: May 2017

Wed, 19 Apr 2017 20:09:22 -0400

Bucking the global trend of glacial retreat, Franz Josef Glacier in New Zealand's Southern Alps advanced for much of the period between 1983 and 2008. Credit: Wendy Mann, CC BY 2.0.

From Antarctica to the Arctic; from polar caps, permafrost and glaciers to ocean-rafted sea ice; and from burly bears to cold-loving microbes, fascinating science is found in every nook and crevasse of Earth’s cryosphere, and new findings are announced often. Here are a few of the latest updates.

Sea-surface temperatures during last interglacial similar to modern day

Wed, 19 Apr 2017 20:02:45 -0400

During the last interglacial period, global sea levels were higher than today but sea-surface temperatures were comparable. Credit: CC0, public domain.

During the last interglacial period, between 129,000 and 116,000 years ago, global sea levels were 6 to 9 meters higher than at present. Scientists have long wondered how global atmospheric and ocean temperatures then compared to modern times, but efforts to reconstruct such temperatures have often fallen short. In a new study, researchers who compiled past records of sea-surface temperatures (SSTs) have revealed that SSTs during the last interglacial were similar to modern day temperatures. But, the similarity doesn’t necessarily predict a future surge in sea levels.

Investigating erionite, asbestos' more carcinogenic cousin

Wed, 19 Apr 2017 14:19:15 -0400

Blocks of volcanic tuff quarried from this mine in Turkey contain carcinogenic erionite. Credit: F. Mighali (Kaltun Italia S.r.l.).

Asbestos is notorious for causing lung cancer and other respiratory diseases, but it’s not the only type of fibrous mineral that affects human health. In the mid-1970s, erionite was linked to the unprecedented high mortality rate from mesothelioma in villages in central Turkey where volcanic tuff had been used as a building material for centuries. Like asbestos, erionite can occur as long thin fibers that, when inhaled, can persist in lung tissue for decades. New research looking at associations of iron with erionite is helping pathologists better understand why embedded erionite fibers sometimes lead to lung cancer.

Fossil forest recorded ancient sunspots

Wed, 19 Apr 2017 14:16:33 -0400

A cross section of fossilized wood from the Permian-aged Chemnitz Petrified Forest showing 75 tree rings. Credit: L. Luthardt and R. Roessler.

The sun’s surface is home to dark, relatively cool blotches of high magnetic activity known as sunspots, which vary in number over a roughly 11-year cycle. In a new study in Geology, scientists found evidence of this solar cycle dating back 290 million years to the Permian Period.

Mountains may cause huge waves in Venusian clouds

Wed, 19 Apr 2017 14:11:23 -0400

A huge stationary wave observed over Venus may result from mountain topography. Credit: Planet-C project/Japan Aerospace Exploration Agency (JAXA).

An enormous, stationary, bow-shaped feature has been detected in the cloud-tops of Venus’ thick, sulfuric acid-rich atmosphere. The structure, stretching more than 10,000 kilometers, remains fixed over Venus’ surface despite atmospheric winds that whip around the planet at 100 meters per second.

First trilobite eggs found in fool's gold

Wed, 19 Apr 2017 14:08:33 -0400

Trilobites are sometimes found preserved in pyrite, such as this specimen from British Columbia. Credit: Mary Caperton Morton.

Trilobites were one of the most successful groups of animals to ever scurry across the seafloor, thriving for more than 270 million years. But how they reproduced has long been a mystery, since no fossil had ever been found with preserved eggs or genitalia. With the discovery of a cluster of trilobite eggs preserved in pyrite in upstate New York, however, scientists are getting the first glimpse of how these early arthropods reproduced.

Grapes reveal impacts of sulfur-rich Samalas eruption on 13th-century climate

Wed, 19 Apr 2017 14:05:44 -0400

Lake Segara Anak fills the caldera formed during Samalas' 1257 eruption. Credit: Petter Lindgren.

The A.D. 1257 eruption of the Indonesian volcano Samalas sent an ash plume an estimated 43 kilometers into the sky in one of the most sulfur-rich eruptions of the last 7,000 years. A new study using tree rings, ice cores and historical records investigates how this colossal eruption impacted climate across the Northern Hemisphere, finding that the eruption triggered severe cold in some regions, while other areas were less affected. The pattern could be explained by the behavior of sulfate particles in the atmosphere, researchers suggest.

Did the first humans arrive in North America a lot earlier?

Wed, 19 Apr 2017 14:01:28 -0400

Dating of this horse mandible from the Bluefish Caves in the Yukon suggests humans were at the site as early as 24,000 years ago. Credit: Bourgeon et al., PLOS ONE, January 2017, CC BY 4.0.

New dating of artifacts recovered from a site in the northern Yukon, on the Alaskan border, may push back the hypothesized entry date of the first American colonizers via a northwestern route — long thought to have occurred over the Bering land bridge between 18,000 and 14,000 years ago — by several thousand years.

Travels in Geology: Geo-diversity and geologic history in the North West Highlands of Scotland

Wed, 19 Apr 2017 13:54:35 -0400

The North West Highlands of Scotland feature rugged mountains and gorgeous valleys with a rich geological history. Credit: Summer Brown.

The North West Highlands of Scotland are sparsely populated, with rugged mountains and gorgeous valleys featuring a rich geological history. The area has the oldest rocks in the United Kingdom as well as some young landscapes freshly sculpted by ice sheets during the last glaciation. Early geological explorations and explanations of the North West Highlands proved perplexing and contentious, in part because the rocks of this region span two-thirds of Earth’s history in age. Additionally, there are, in places, sedimentary layers sandwiched between metamorphic packages of gneiss and schist. How did this happen? Was the schist deposited like a sedimentary rock atop the sandstone and limestone? Was it a former sedimentary layer that for some reason was exceptionally metamorphosed relative to the layers beneath it? Throw in three separate unconformities and the picture becomes even more muddied. You start to see why multiple generations of British geology students have traveled here for field camps.

Did Jurassic tectonics lead to supergiant oilfields?

Tue, 18 Apr 2017 12:26:44 -0400

Rapid tectonic movements that shuttled the Arabian Plate from near the equator to the southern tropics and back again in the Middle and Late Jurassic may have led to the formation of Arabia's giant oilfields, including the massive Ghawar field. Credit: K. Cantner, AGI.

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.

Tallying temperature drops inside tornadoes

Tue, 18 Apr 2017 12:22:56 -0400

A tornado passes near the Scottsbluff, Neb., airport on June 27, 1955. Credit: National Archives and Records Administration.

The inside of a strong tornado is an intense place, with wind speeds of more than 450 kilometers per hour and dramatic drops in air pressure and temperature. But due to the dangerous unpredictability of such storms, few real-time measurements have been taken inside actual twisters. In a new study, researchers took a mathematical approach to circumvent the danger and calculate temperature changes inside tornadoes, offering a glimpse into how these violent storms operate.

Venezuela, Central Africa are Earth's lightning hot spots

Tue, 18 Apr 2017 12:18:23 -0400

Thunderstorms occur roughly 297 days per year above Lake Maracaibo in Venezuela. Credit: NASA.

People who live around Venezuela’s Lake Maracaibo call it a “lighthouse.” The lake’s “never- ending storm” has been written about for centuries, and the incessant lightning there has even helped guide Caribbean sailors. Data from NASA’s Tropical Rainfall Measuring Mission (TRMM) has now confirmed that Lake Maracaibo is Earth’s top lightning hot spot.

Tropical rainfall shifts resulted in greener Sahara

Tue, 18 Apr 2017 12:14:56 -0400

Thousands of years ago, the Sahara was dotted with lakes and vegetation. Credit: Wonker, CC BY 2.0.

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.

Massive dust storm caused by climate, not conflict

Tue, 18 Apr 2017 12:09:21 -0400

A massive dust storm, seen here on Sept. 8, 2015, in NASA MODIS imagery, swept across the Middle East in late summer 2015. Credit: NASA Worldview.

In August and September 2015, a massive dust storm swept across the Middle East, engulfing seven nations in sand thick enough to ground flights, trigger respiratory distress for many, and obscure the region from satellites. At the time, the unprecedented size of the storm was blamed on the ongoing conflict in Syria, with unusual amounts of dust being raised from abandoned agricultural lands and increased military traffic. But a new study cites a combination of climatic factors and weather as the more likely culprits.

Tiny dinosaur-era marsupial packed a big bite

Tue, 18 Apr 2017 09:33:54 -0400

An artist's depiction of Didelphodon on the hunt. Credit: Misaki Ouchida.

Newly described fossils from one of the earliest-known marsupials are shedding light on the evolution of mammals during the Mesozoic and revealing an animal with an impressive bite, perhaps strong enough to take down a dinosaur.

Scientists crack the secret of dinosaurs' incubation time

Tue, 18 Apr 2017 09:21:40 -0400

Gregory Erickson examined teeth in dinosaur embryos to assess their incubation times. Credit: Bill Lax/FSU Photography Services.

Paleontologists have long thought that the eggs of dinosaurs — like those of their living bird relatives — probably hatched after short incubation times, up to a few weeks at most. But surprising results from a new study suggest that nonavian dinosaurs spent anywhere from three to six months inside an egg, incubation times similar to reptiles like crocodiles and alligators.

Neonicotinoids: Prominent pesticides escape into the environment

Fri, 14 Apr 2017 09:48:30 -0400

Credit: K. Cantner, AGI.

The 1990s was a watershed era in pest control — and, by extension, agriculture — thanks to a particular bit of chemical innovation. With the emergence of a compound called imidacloprid onto the insecticide market, farmers — from those growing rice, corn and other staples, to orchard owners cultivating fruit trees, to backyard gardeners tending vegetable patches — had a powerful new tool with which to combat aphids, beetles, weevils, whiteflies and a host of other insects with a knack for damaging crops.