April 2018 on EARTH Magazine

Mineral Resource of the Month: Sulfur

Tue, 12 Jun 2018 12:53:06 -0400

By Lori E. Apodaca, USGS mineral commodity specialist

PRODUCTION

GEOLOGIC OCCURRENCE

In 1777, French chemist Antoine Lavoisier showed that sulfur was an element, not a compound. Credit: Eric Hunt, CC BY-SA 2.5

Sulfur is one of the few elements found in elemental form in nature and has been used in elemental form since ancient times. It forms near volcanic vents and fumaroles, and small quantities of native sulfur form during the weathering of sulfate and sulfide minerals. However, the largest concentrations of sulfur are found associated with sulfide ore mineral deposits and with evaporative minerals in salt domes. As the 16th-most abundant element in Earth’s crust, sulfur is plentiful and can be found around the world.

Geoscience on Film: Roadcuts and rockfalls in mountainous Mizoram

Wed, 18 Apr 2018 13:15:11 -0400

Aizawl, the capital of the Indian state of Mizoram, is draped over a mountain ridge. An example of the typical construction style in Aizawl — a multi-story home supported by concrete stilts atop the steep hillside — can be seen at right in the foreground. The remnant of a damaging landslide can be seen in the center of the photograph. Credit: Martin Prose

Doug Prose, formerly a geologist with the U.S. Geological Survey, has co-produced documentaries showcasing Earth and the geosciences with his partner and wife, Diane LaMacchia, through their nonprofit Earth Images Foundation since 1992. Recent films include “Earth: The Inside Story” and “Italy’s Mystery Mountains,” both released in 2014. Their latest documentary, “The Himalaya Connection,” began airing on PBS stations in April. Prose has previously written and blogged for EARTH about the pair’s experience shooting and preparing “Connection,” which involved six separate trips to Bangladesh, Bhutan, India, Mongolia and Nepal from 2011 to 2016. They recently traveled back to the region for their next project. Prose wrote about the trip while there, and filed the following series of posts upon returning home. Read posts in this series, as well as from prior trips, here.

Geomedia: Television: "One Strange Rock" is Superlative

Wed, 11 Apr 2018 13:58:52 -0400

If I only had one word to describe the new 10-part National Geographic documentary series “One Strange Rock,” produced by Darren Aronofsky and Jane Root, it would be “superlative.” But don’t misunderstand me: The series is not remarkable because it’s the best nature documentary I’ve ever seen. It’s not, although it does feature gorgeous footage and state-of-the-art, digitally generated animations, and perhaps covers a wider range of earth science topics than other documentaries in the genre. Instead, it is superlative in the way that Americans make many things superlative — with hyperbole.

How Borneo got its elephants

Tue, 10 Apr 2018 11:58:46 -0400

The Bornean elephant is the smallest subspecies of elephant. This baby is one of fewer than 2,000 individuals that remain in the wild. Credit: Rudi Delvaux.

Elephants may not seem like islanders, but a small population lives on the Southeast Asian island of Borneo. How and when the animals arrived on the island has long been a mystery. A new DNA analysis points to colonization at the end of the Pleistocene, when a land bridge may have connected Java, Borneo and Sumatra to the Malay Peninsula and mainland Asia.

Lidar preserves record of destroyed theropod tracks

Tue, 10 Apr 2018 11:55:41 -0400

Researchers document a theropod dinosaur trackway at a gypsum quarry in Arkansas. Credit: University of Arkansas.

In 2011, the first theropod dinosaur tracks ever discovered in Arkansas were uncovered at an active gypsum quarry near Nashville in the southwestern part of the state. Over two weeks, researchers collected a set of high-resolution digital scans of the trackway that has now allowed scientists to piece together its 100-million-year-old story, even though the tracks have long-since been destroyed by mining operations.

Origins of plant photosynthesis illuminated

Tue, 10 Apr 2018 11:49:51 -0400

Bangiomorpha pubescens is a fossil red alga that's now the oldest-known direct ancestor of plants. Credit: Nicholas Butterfield.

Photosynthesis, the process by which plants harness sunlight to make their food, is a defining feature of plants and an important evolutionary development. But when photosynthesis evolved in ancient plant ancestors is not clear. The Precambrian fossil red alga Bangiomorpha pubescens, discovered in the Canadian Arctic in 1990 by University of Cambridge paleobiologist Nicholas Butterfield, displays evidence of traits that suggest it photosynthesized the way plants do, but the exact age of the fossil was also unknown. In a new study, researchers report an age for the alga of about 1.047 billion years, making it the oldest-known direct ancestor of plants.

Radium levels suggest Arctic Ocean chemistry is changing

Tue, 10 Apr 2018 11:44:26 -0400

In 2015, researchers measured radium in the Arctic Ocean from the Chukchi Shelf (where the voyage started) to the North Pole. Elevated radium levels (shown in bright yellow along the cruise route) were found near the North Pole, possibly as a result of transport from the East Siberian Arctic Shelf. Credit: Natalie Renier, Woods Hole Oceanographic Institution.

Rising temperatures have already caused changes in the Arctic environment, like diminishing sea ice and thawing permafrost. Now, it appears that sea-ice loss could be throwing Arctic Ocean chemistry out of whack.

Whatever happened to thagomizers and other tail weapons?

Tue, 10 Apr 2018 11:39:45 -0400

New research finds that extinct, tail weapon-wielding animals — such as the dueling ankylosaurs illustrated here — all shared a set of traits, including large body size, herbivory and bony body armor, that no modern animals possess. Credit: Jack Mayer Wood.

Stegosaurus wielded a spiked tail — dubbed a “thagomizer” by cartoonist Gary Larson and informally adopted by paleontologists — which the herbivorous dinosaur likely used for defense against hungry predators. Other extinct animals also sported foe-clobbering tail weapons: Ankylosaurus had a tail club, as did extinct mammals like the glyptodonts, giant armadillo-like animals that once roamed the Americas. Today, though, thagomizers and bony tail clubs are things of the past. In a new study, paleontologists have found that extinct animals with such weapons all shared a now-antiquated set of traits: They were large, herbivorous, and had body armor and a stiff torso.

Hot tropics drove out ancient reptiles, but they came back

Tue, 10 Apr 2018 11:33:16 -0400

Terrestrial reptiles vacated the tropics (orange and yellow belts) following the end-Permian mass extinction 252 million years ago. Credit: MUSE Archive.

About 252 million years ago, massive volcanic eruptions in what is now Siberia rapidly warmed Earth, resulting in the end-Permian mass extinction that saw most terrestrial and marine species die off. It’s been thought that surviving reptiles and fish fled the hot tropics and didn’t return for millions of years. But according to new research, the tropical evacuation may not have lasted so long after all.

Battery recycling underlies elevated lead in African soils

Tue, 10 Apr 2018 11:22:11 -0400

Lead-acid batteries — used to power motor vehicles and cellphone towers, and for power storage at wind and solar farms — are one of the most recyclable products, but they are also highly toxic. Credit: baselactionnetwork, CC BY-ND 2.0.

Of all the recycling industries in the world, lead-acid battery recycling is one of the most profitable — and one of the most toxic. In the U.S., regulations on the industry have dramatically reduced lead exposure and pollution at battery recycling plants. But in Africa, where the industry is growing and largely unregulated, lead levels are skyrocketing. A new study in Environmental Research looking at environmental lead levels in seven African countries is shining a spotlight on the ongoing public health crisis.

Unprecedented exploration of undersea volcano yields surprising results

Tue, 10 Apr 2018 11:14:14 -0400

Lava from the 2012 eruption of the Havre underwater volcano is shown in shades of red in this high-resolution model. Credit: University of Tasmania/Woods Hole Oceanographic Institution.

Underwater volcanic eruptions happen every day, but because of the vastness of the ocean and the great depth of water blocking the view, catching an active eruption is a game of chance. In fact, the largest-known underwater eruption of the past century was something of a fluke discovery. In July 2012, an airline passenger spotted a huge pumice raft floating in the South Pacific during a flight to Auckland, New Zealand. Upon landing, she alerted researchers, and scientists confirmed the 400-square-kilometer pumice raft near the Havre Seamount using NASA satellite imagery.

World's longest underwater cave found in Mexico

Tue, 10 Apr 2018 11:06:37 -0400

A connection between the Dos Ojos (seen here) and Sac Actun caves near Tulum, Mexico, was recently discovered. The newly combined cave system is now the longest-known underwater cave in the world. Credit: Guillén Pérez, CC BY-ND 2.0

In January, scientists and underwater explorers working with the Great Maya Aquifer (Gran Acuífero Maya, or GAM) project discovered the world’s longest flooded cave system, which stretches 347 kilometers in Quintana Roo on Mexico’s Yucatán Peninsula.

Down to Earth With: National Park Service senior paleontologist Vincent Santucci

Tue, 10 Apr 2018 09:56:08 -0400

Vincent Santucci is the senior paleontologist and paleontology program coordinator at the National Park Service. Credit: NPS photo.

When Vincent Santucci was hired in 1985 to work as a seasonal ranger in South Dakota’s Badlands National Park, he assumed the most formative part of the experience would be sharing his unbridled enthusiasm for fossils with park visitors. But as Santucci explored the colorful badlands on his days off, he sometimes stumbled across people who were illegally collecting fossils. Following the first of these encounters, Santucci raced back to headquarters to report the illicit activity with the expectation that the chief ranger would rush out and arrest the perpetrator. Much to Santucci’s surprise, the ranger instead put a hand on his shoulder and drawled, “You ain’t from around here, are you, boy?” After several repeat episodes, Santucci learned that when rangers had previously caught illegal collectors and brought them before the local magistrate, the judge had refused to prosecute, citing a lack of fencing or signage that clearly informed the fossil hunters they’d been on federal land.

Getting there and getting around Oman

Mon, 09 Apr 2018 15:25:15 -0400

Oman’s main gateway is Muscat International Airport (MCT), which offers service to most major Middle Eastern and European cities. There are no direct flights to Oman from North America; it’s usually most convenient to fly through Dubai, Doha, Bahrain or a major European city. Emirates, Qatar Airways, Gulf Air, Oman Air and Turkish Airlines are among those that offer connecting service. The airport is located on the western edge of the capital city; if your hotel doesn’t offer a free shuttle, you can reach the downtown via blue-striped airport taxis, which operate on a fixed, prepaid rate, or one of the microbuses that depart from the opposite side of the footbridge that spans the highway outside the airport.

Slumgullion: Colorado's natural 'lab' offers insights into landslides worldwide

Mon, 09 Apr 2018 14:35:55 -0400

The enormous Slumgullion landslide in southwestern Colorado has been moving — sometimes imperceptibly slowly — every day for some 300 years. Credit: William Schulz, USGS.

In southwestern Colorado, a centuries-old “laboratory” looks out on the snowy peaks of the Lake City Caldera in a remote section of the San Juan Mountains. The lab’s scientists don’t wear white coats, but Gore-Tex and hiking boots, and they don’t work inside a building but on a 6.8-kilometer-long mishmash of red, brown and yellow earth topped with boulders, ponds and tilted spruce. Early settlers to the region called the mass Slumgullion, after an “everything-but-the-kitchen-sink” stew, with “slum” being an old word for “slime” and “gullion” an English term for “cesspool.”

From farm to filter: Restored wetlands remediate nitrogen pollution

Mon, 09 Apr 2018 11:21:45 -0400

Bottomland hardwoods are a predominant wetland type in the Mississippi Alluvial Valley, the historic floodplain and valley of the lower Mississippi River. Credit: U.S. Fish and Wildlife Service.

Nitrogen giveth and nitrogen taketh away: It’s been estimated that roughly half of the world’s population today could not exist without nitrogen fertilization. Although land area on Earth remains roughly the same on human timescales, population continues to rise, requiring more intensive and rigorous use of existing agricultural land and the creation of more agricultural lands to meet the ever-growing demand for food. One way humanity has supported population growth is through the manipulation of nitrogen, a limiting nutrient in terrestrial ecosystems. In 1913, the advent of the Haber-Bosch process, which artificially converts nitrogen gas to bioavailable ammonia, revolutionized access to nitrogen and all but eliminated nitrogen limitation in terrestrial ecosystems. Now, nitrogen fertilizers are often heavily applied to croplands to increase plant growth and productivity.

Geomedia: Books: Solar eclipses past, present and future

Mon, 09 Apr 2018 10:54:25 -0400

American Eclipse: A Nation's Epic Race to Catch the Shadow of the Moon and Win the Glory of the World, by David Baron, Liveright/W.W. Norton, Paperback, 2018, ISBN 9781631494550.

On Aug. 21, 2017, a total solar eclipse traversed across the United States, from the western coast of Oregon to the eastern shores of South Carolina. I witnessed about one minute and 50 seconds of totality from Salem, Ore., where the skies were unusually clear — despite the wildfires then raging around the West. In eclipse parlance, totality refers to the period when the moon — which, in the most mind-blowing of cosmic coincidences, just happens to be the same angular size in the sky as the sun — completely blocks the sun’s bright disk and reveals the tenuous outer solar atmosphere known as the corona.

Earth's "hum" heard at ocean bottom

Tue, 03 Apr 2018 16:09:49 -0400

An ocean-bottom seismometer is deployed in the Indian Ocean. Credit: RHUM-RUM experiment/Meteor Cruise

Lapping waves or crashing surf may come to mind for most people when they imagine the sounds of the ocean. But the ocean has other voices as well, including one produced by interactions of waves with the seafloor along the continental slope. Unlike waves on the shoreline, this steady, low sound, or “hum,” is inaudible to the human ear and has even proven difficult to detect in recordings made by ocean bottom seismometers (OBS). But in a new study in Geophysical Research Letters, researchers analyzing OBS data have now clearly identified the hum for the first time, which may allow it to be used to develop a better picture of Earth’s interior structure.

Where on Earth? - April 2018

Fri, 30 Mar 2018 12:03:59 -0400

Click to enlarge photo.

Clues for April 2018:

This 1.1-square-kilometer Alpine lake lies at an elevation of 1,578 meters and is part of the host mountain range’s first UNESCO World Heritage site, designated in 2001. Although accessible only via gondola and foot, it is a popular destination for ice fishing and skating as it remains frozen five months of the year.
The 50-meter-deep lake is fed by glacial streams, but has no surface drainage. Lakewater percolates down through the permeable rock avalanche deposit damming the lake, which was recently shown to have been produced by two separate landslides that occurred roughly 2,300 years ago, and were likely triggered by a seismic event.
The lake is about 50 kilometers south-southeast of its host country’s capital city, and lies in a region famous for producing a popular type of holey cheese.

Geologic Column: Over the hills and far away

Tue, 27 Mar 2018 12:31:26 -0400

Credit: Sam Romilly CC BY-SA 2.0

Tom, he was a piper’s son, He learnt to play when he was young, And all the tune that he could play Was “Over the Hills and Far Away."

Travels in Geology: Underground awe in France: The caves of the Causses

Fri, 23 Mar 2018 12:25:26 -0400

The village of Saint-Cirq-Lapopie is built on a hill above the Lot River Valley. Credit: Callan Bentley.

The Causses du Quercy Natural Regional Park, usually just called “the Causses” (pronounced like “coast” without the “t”), in south-central France is a classic Gallic landscape of gently rolling hills divided millennia ago into farm plots, livestock grazing pastures, low, dense forests and small stone-carved towns. It’s a place where the roads curve and wiggle, the butterflies dance in the sun, and people take long lunches at outdoor patios adjacent to the local “auberge” (inn). Strolling along the tree-lined roads, you hear the buzz of insects and glimpse backyard vegetable gardens, and after a tiny car passes you with a wave, you discover a Neolithic tomb, or dolmen, surrounded by vines. The dolmen speaks profoundly of how humans have inhabited the Causses for a very long time.

Getting there and getting around the Causses

Fri, 23 Mar 2018 12:16:19 -0400

Visitors to the Causses region can find places to stay in any of dozens of charming towns throughout the region. Credit: both: Callan Bentley.

Toulouse is the best gateway to the Causses region. Toulouse-Blagnac Airport hosts plenty of flights to connecting cities in Europe, but no direct flights from the United States. Rent a car at the airport and head north to explore the region. The main highway going north to the Causses is well maintained, with fueling stations along the way that offer everything a traveler might need, including showers. Figuring out how to pay for gasoline was tricky — but that’s part of the adventure of travel.

Pairing geoheritage and economic development: China's Guizhou Province offers a modern model

Thu, 22 Mar 2018 14:00:53 -0400

Guizhou Province is known for its stunning karst topography. Credit: ©iStockphoto.com/KingWu.

As I admired an immaculately preserved colony of 230-million-year-old crinoids lying next to an equally impressive skeleton of a sharp-toothed ichthyosaur at China’s Guanling Fossil Group National Geopark, I thought back to family trips to North American national parks during my youth. The natural wonders I saw on those trips strongly influenced my career choice and shaped my perception of how humans fit into Earth’s long history. Today, even after more than 35 years spent studying the Earth, every visit to a spectacular natural site like this one in Guanling still engenders the same excitement and insight I had as a youngster.

Acid rain triggered deadly Chinese landslide

Tue, 20 Mar 2018 15:11:42 -0400

The Jiweishan landslide began high on these cliffs at the interface between limestone and shale layers, sending tons of rubble into the valley. Credit: Mauri McSaveney.

On June 5, 2009, a catastrophic landslide killed 74 people in southwestern China. But a lack of recent earthquake activity or heavy rainfall left geologists questioning what had triggered the slide. A new study suggests that China’s acid rain may have played a role in weakening the limestone and shale slope in unexpected ways.

Red Planet Roundup: April 2018

Tue, 20 Mar 2018 14:58:07 -0400

A steep, ice-rich scarp (in blue) drops roughly 130 meters vertically in this color-enhanced image taken by the HiRISE camera aboard the Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/UA/USGS.

With two rovers patrolling the surface of Mars, six spacecraft orbiting above it, and scientists here on Earth studying the Red Planet from afar, new findings are announced often. Here are a few of the latest updates.

Benchmarks: April 4, 2011: Air France Flight 447 wreckage found using modern oceanography tools

Tue, 20 Mar 2018 14:32:27 -0400

On June 1, 2009, Air France flight 447 (AF447) from Rio de Janeiro to Paris crashed in the Atlantic Ocean near the mid-ocean ridge, killing all 228 passengers and crew aboard. Credit: BEA, France, bea.aero.

In the early morning hours of March 8, 2014, Malaysia Airlines flight 370 (MH370), en route from Kuala Lumpur to Beijing, lost communication with air traffic control during the transition between Malaysian and Vietnamese air space. It then disappeared, along with all 239 people aboard.

Down to Earth With: Conservation engineer Emily Pidgeon

Mon, 19 Mar 2018 14:29:28 -0400

Emily Pidgeon, senior director of the oceans and climate program at Conservation International, led the formation of the Blue Carbon Initiative, an international nonprofit organization that works to mitigate climate change by protecting coastal ecosystems. Credit: Sarah Derouin.

“I can be a very blunt object,” says Emily Pidgeon, describing how she moves through the world and how she approaches her work. Her Australian accent, drawling yet punctuated, rises above the din of the lunch crowd at a café. She pauses a moment, and declares herself a larrikin. “Do you know that word, larrikin?” She explains that Australians have a larrikin culture — they’re troublemakers, but in a good way. “We have a healthy disrespect for authority,” she says, sipping her tea.

Chemical tipping point triggers eruptive transitions

Mon, 19 Mar 2018 14:23:18 -0400

Mount Pinatubo in the Philippines is most famous for the explosive phases of its 1991 eruption, but the months-long eruption was also punctuated by gentler periods of oozing lava. Credit: U.S. Geological Survey.

During an eruption, some volcanoes vacillate unpredictably between effusive and explosive behavior. New research has identified a chemical tipping point in some magmas that may trigger the transition between such mild and violent eruptive cycles.

No river meant no floods for ancient Indus settlements

Mon, 19 Mar 2018 14:20:46 -0400

The path of the Ghaggar-Hakra paleochannel can be seen in this composite Landsat image. The modern Sutlej River may have flowed through the paleochannel prior to the development of Indus Civilization cities. Credit: P.J. Mason/S. Gupta, Imperial College London; Landsat imagery courtesy of NASA Goddard Space Flight Center and U.S. Geological Survey.

Large Middle Eastern rivers like the Nile, Tigris, Euphrates and Tiber were critical for the development of early urban societies in Egypt, Mesopotamia and Ancient Rome. And researchers have long thought that the rise, and eventual decline, of cities in the ancient Indus Civilization, which spread across about 1 million square kilometers of what’s now northwestern India and Pakistan from roughly 4,600 to 3,900 years ago, also depended on major rivers, namely those emerging from the Himalayas. But a new study looking at river sediments from the time of the civilization and earlier suggests that wasn’t the case for every ancient Indus city; some may have benefited from being farther away from large rivers and their periodic floods.

Oldest "Third Pole" ice core recovered

Mon, 19 Mar 2018 14:17:39 -0400

Lonnie Thompson cuts an ice core retrieved from the Guliya Ice Cap in the Kunlun Mountains in Tibet. Credit: Giuliano Bertagna/Byrd Polar and Climate Research Center.

Holding massive reservoirs of ice, high-altitude glaciers, such as those in the Himalayas, are sometimes referred to as Earth’s “Third Pole.” The Guliya Ice Cap, on the Tibetan Plateau, has now produced the oldest ice ever drilled outside the Arctic or Antarctica.

Ceres: A bright spot in the asteroid belt

Mon, 19 Mar 2018 14:14:51 -0400

A color-coded topographic map of Occator Crater on Ceres (blue indicates the lowest elevation and brown the highest). The 34-million-year-old crater, approximately 92 kilometers wide and 4 kilometers deep, contains the brightest material on the dwarf planet. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Orbiting in the asteroid belt between Mars and Jupiter, Ceres is the nearest dwarf planet to Earth and the only one within the inner solar system. It has been studied closely by NASA’s Dawn spacecraft since March 2015.

Residual strain explains later quakes

Mon, 19 Mar 2018 14:12:33 -0400

The Nazca Plate, moving eastward at a rate of 6.6 centimeters per year, collides with, and dives beneath, the South American Plate off the Chilean coast, building strain. Credit: K. Cantner, AGI, after GEBCO world map 2014, gebco.net.

The largest earthquake in recorded history struck southern Chile on May 22, 1960. The magnitude-9.5 temblor was followed by a tsunami that, combined with the seismic shaking, killed 1,600 people and left more than 2 million homeless. New research suggests that, despite the staggering size of the event, the shaking didn’t dissipate all the strain accumulated at the time on the subduction fault between the Nazca and South American tectonic plates. The residual strain left on the fault may explain why a portion of this same section of fault ruptured again — 56 years later — on Dec. 25, 2016, in a magnitude-7.6 event.

Measuring earthquakes using fiber-optic cables

Mon, 19 Mar 2018 14:09:33 -0400

Nathaniel Lindsey of the University of California, Berkeley, buries fiber-optic cable in a trench near Fairbanks, Alaska, to record earthquake seismicity. Credit: left: Anna Wagner; right: Nathaniel Lindsey.

Fiber-optic cables crisscross the world, ferrying digital data and enabling internet access and telecommunication. In a new study, published in Geophysical Research Letters, researchers tested whether fiber-optic cables can also be used to detect and measure earthquakes.

Surveying forests from afar

Mon, 19 Mar 2018 14:06:44 -0400

Researchers used airborne imaging and spectroscopic techniques to study the diversity of forests in Switzerland's Laegern Mountains. Credit: UZH.

Traditional surveys of forest health and diversity take hours of hiking and sampling by scientists who can only cover relatively small areas. Satellites, meanwhile, can survey large swaths of land, collecting information about forests in a fraction of the time that a ground survey might take. But the resolution and types of satellite data available don’t always allow for detailed studies. Now, a team of ecologists is staking out the middle ground by developing airborne laser scanning techniques to create high-resolution maps of tree species diversity to monitor changes in forest ecosystems.

Globe-trotting bacteria found at both poles

Mon, 19 Mar 2018 14:04:01 -0400

University of Tübingen geoscientist Julia Kleinteich collects water samples in Antarctica. Credit: Daniel Farinotti.

The Arctic and Antarctica, separated by more than 15,000 kilometers, may be geographic opposites but they share many similarities, including their diverse arrays of bacteria and other microscopic life forms. A new study looking at the DNA of bacteria from both poles has found remarkable similarities between the two regions’ bacterial diversity, including some of the same species.

Pesky ticks even plagued dinosaurs

Wed, 14 Mar 2018 15:13:08 -0400

A tick grasps a dinosaur feather in a piece of 99-million-year-old amber. Credit: E. Peñalver et al., Nature Communications, December 2017.

Blood-sucking, disease-spreading ticks are one of the most maligned parasites in the world, and new evidence shows they’ve been doing their dirty work for a long time: Fossilized ticks dating to the mid-Cretaceous represent the first direct evidence that the ancestors of today’s pesky critters once plagued dinosaurs.

Carbon emissions spike when continents rift

Wed, 14 Mar 2018 13:40:14 -0400

Part of the East African Rift, the largest continental rift on Earth today, in southern Kenya as seen from the International Space Station in 2012. Many of the linear features running from the bottom-left (north) to top-right (south) are scarps formed by faulting associated with the rift. Credit: NASA.

The vast majority of Earth’s carbon is stored in the planet’s interior. This buried carbon is not isolated from the surface over geologic timescales, however; some of it is released back into the atmosphere as carbon dioxide and other gases when volcanic eruptions occur above subduction zones or island arcs. In a couple of new studies, researchers have identified another major component in the global carbon cycle: continental rift faults. Such faults, like those found along the East African Rift today, may contribute even more carbon dioxide to the atmosphere at times than volcanoes.

Gyres spin up, currents get muddled

Thu, 08 Mar 2018 11:37:13 -0500

In the Weddell Sea Gyre, one of two clockwise-spinning circulation patterns in the Southern Ocean, warming has accelerated the spinning. Recent research suggests this acceleration — and the warmer, faster-moving Antarctic Circumpolar Currrent and Circumpolar Deepwater that result — may trigger the development of smaller, shorter-lived polynyas like those observed over the past two years. Credit: K. Cantner, AGI.

In addition to polynya formation and warming-induced surface freshening, other factors may also impact open-ocean convection in the Southern Ocean. The warming atmosphere is shifting global climatic zones and their associated wind fields poleward in both hemispheres. In the Weddell Sea Gyre, one of two clockwise-spinning circulation patterns in the Southern Ocean, this shift has resulted in a dramatic increase in wind stress curl (the strength of the wind’s influence on ocean water flow) over the past two years.

Disrupting the deep: Ocean warming reaches the abyss

Thu, 08 Mar 2018 11:29:52 -0500

SOCCUM Project, Hannah Zanowski, CC BY 2.0

Seventy-one percent of our planet is covered by ocean, and these basins contain 97 percent of Earth’s near-surface water. The ocean lies at the heart of the global climate system, shaping all parts of our environment, even in the deepest continental interiors. So as the ocean goes, so goes the planet — and the ocean is warming.

Geomedia: On the Web: How will melting ice impact your city?

Thu, 08 Mar 2018 10:07:44 -0500

Gradient fingerprint mapping can be used to determine how the loss of distant land-ice will impact local sea-level rise. These gradient maps show how ice loss from the Greenland Ice Sheet (left) and Antarctica (right) will affect sea-level rise near New York City. Ice loss from areas colored red will have a larger impact on New York's local sea-level rise, while melting in blue regions will have little to no impact on sea-level rise in New York. Antarctic melting will affect New York far more than Greenland melting. Credit: Larour et al., Science Advances, November 2017.

The relationship between melting glaciers and rising sea levels is best described as: “It’s complicated.” A new online tool shows just how counterintuitive predictions of how melting land-ice will affect coasts can be.

No river meant no floods for ancient Indus settlements

Mon, 22 Jan 2018 16:06:40 -0500

This remnant of a street was excavated at the site of the Indus Civilization urban center of Kalibangan, which was situated along the Ghaggar-Hakra palaeochannel. Credit: S. Gupta, Imperial College London

Climate change linked to specific weather events for the first time

Thu, 14 Dec 2017 16:12:41 -0500

Most of the extreme weather events of 2016 were found to have been caused by or exacerbated by human-induced climate change. Credit: AMS/NOAA.

Three extreme weather events that occurred in 2016 would not have been possible in Earth’s pre-industrial climate, according to the sixth annual report on the attribution of extreme weather events issued Dec. 13 by NOAA and the American Meteorological Society (AMS). This marks the first time that researchers have concluded that a specific weather event would not have been possible without the influence of humans.