New Study Highlights Mantle Plumes and Yellowstone Supervolcano

In a new study, reported in the journal Nature Geosciences, University of Illinois geologists, Lijun Liu and graduate students Quan Zhou and Jiashun Hu used a technique called seismic tomography to peer deep into the subsurface of the western U.S. and piece together the geologic history behind the volcanism. Using supercomputers, the team ran different tectonic scenarios to observe a range of possible geologic histories for the western U.S. over the past 20 million years. The effort yielded little support for the traditional mantle plume hypothesis.

Recent stories in the national media are magnifying fears of a catastrophic eruption of the Yellowstone volcanic area, but scientists remain uncertain about the likelihood of such an event. To better understand the region’s subsurface geology, Uof I geologists have rewound and played back a portion of its geologic history, finding that Yellowstone volcanism is more far more complex and dynamic than previously thought.

“The heat needed to drive volcanism usually occurs in areas where tectonic plates meet and one slab of crust slides, or subducts, under another. However, Yellowstone and other volcanic areas of the inland western U.S. are far away from the active plate boundaries along the west coast,” said Liu who led the new research. “In these inland cases, a deep-seated heat source known as a mantle plume is suspected of driving crustal melting and surface volcanism.”

The teams goal is to develop a model that matches up with what they see both below ground and on the surface today. “We call it a hybrid geodynamic model because most of the earlier models either start with an initial condition and move forward, or start with the current conditions and move backward. Our model does both, which gives us more control over the relevant mantle processes” says graduate students Quan Zhou.

One of the many variables the team entered into their model was heat. Hot subsurface material – like that in a mantle plume – should rise vertically toward the surface, but that was not what the researchers saw in their models.

“It appears that the mantle plume under the western U.S. is sinking deeper into the Earth through time, which seems counterintuitive,” Liu said. “This suggests that something closer to the surface such as an oceanic slab originating from the western tectonic boundary – is interfering with the rise of the plume.”

As for likelihood of a violent demise of Yellowstone occurring anytime soon, the researchers say it is still too early to know. “Perhaps more importantly, this work will give us a better understanding of some of the mysterious processes deep within the Earth, which will help us better understand the consequences of plate tectonics, including the mechanism of Earthquakes and volcanoes.”

Lava-Filled Blocks On Venus May Indicate Geological Activity

For planetary scientists, Venus’s geologic heartbeat flat-lined around 700 million years ago.

Now, a global view of some well-known deformation features on Venus’s surface may indicate it’s capable of crustal motion, and that motion might even be happening today, scientists reported Monday at the 2017 American Geophysical Union Fall Meeting in New Orleans.

Scattered on Venus’s surface are various narrow mountain ridges and surface grooves, or grabens. Scientists have known about these Venusian features for decades, but had only viewed them in isolation from one another.

Paul Byrne, a planetary geologist at North Carolina State University who presented the new research, and his colleagues used radar images of Venus’s surface from the Magellan mission between 1990 and 1994 to view these structures from a global perspective. Doing so revealed a new pattern: these mountain ridges and grabens converge to isolate blocks of flat, low-lying plains of cooled lava along the planet’s poles, something never noticed before.

“When you zoom out, you see that these features form a connected pattern,” Byrne said. “That’s when you realize that they seem to be working together.”

From this higher vantage point, the structures looked a lot like features seen on Earth, such as the Tarim Basin in northwestern China. Basins like Tarim are large pieces of continental crust that jostle, rotate and crash into surrounding terrain due to forces from the mantle below. Consequently, the basins deform the surrounding terrain into mountain ranges or grabens—features identical to those on Venus.

That uncanny similarity persuaded the team that a comparable process may be happening on Venus. With the scorching 462-degree Celsius (864-degree Fahrenheit) temperature at Venus’s surface, Byrne and his colleagues estimate the crust could heat enough that it will slightly detach from the planet’s mantle only 10-15 kilometers (6-9 miles) down, creating thin, “crustal blocks” that could jostle, crash and rotate just like those on Earth.

“It’s not plate tectonics,” Byrne said, “but it does suggest that the outer, rigid, brittle surface layer of Venus, in some places at least, has broken into these small blocks,” many of them only a couple hundred kilometers to as many as 1200 kilometers (745 miles) across.

What excited Byrne the most were signs of deformation within a few of the lava plains. The presence of any deformation atop the young lava—a meager 700 million years old—indicates “at least some of the jostling and moving and rotating could have taken place very recently,” he said. For a planet theorized to have had no activity in millions of years, that prospect seemed revolutionary.

Byrne compared this jostling process to the three layers in a Mars Bar: Venus’s thin upper crust as the chocolate, its more fluid mantle as the caramel, and its deeper core as the nougat. If you put your Mars Bar into the fridge, pull it out, and try to break it, each layer breaks in its own way. The thin chocolate “crust” breaks into discrete chunks, whereas the caramel goes “all flowy.”

“That’s essentially what characterizes the mechanical behavior of this stuff,” Byrne said.

But what could cause these tumultuous blocks to jostle in the first place? And why only at the poles?

Byrne could only conjecture, but he suspects one possibility is very slow convective movement in the mantle. With the thin crust at the surface sitting only tens of kilometers above the mantle, convective motion could slowly push or drag surface chunks along. But because an enormous spreading rift also exists around the equator of Venus, it’s possible that a global spreading process systematically pushes these blocks, causing them to jostle and deform.

“Again, it’s not plate tectonics,” Byrne emphasized. “These are little chunks of land that just rotate and move around. But if we were to put seismometers on Venus, maybe you’d hear some of these chunks go off today.”

Oldest Fossils Ever Found Show Life On Earth Began Before 3.5 Billion Years Ago

Researchers at UCLA and the University of Wisconsin-Madison have confirmed that microscopic fossils discovered in a nearly 3.5 billion-year-old piece of rock in Western Australia are the oldest fossils ever found and indeed the earliest direct evidence of life on Earth.

The study, published today in the Proceedings of the National Academy of Sciences, was led by J. William Schopf, professor of paleobiology at UCLA, and John W. Valley, professor of geoscience at the University of Wisconsin-Madison. The research relied on new technology and scientific expertise developed by researchers in the UW-Madison WiscSIMS Laboratory.

The study describes 11 microbial specimens from five separate taxa, linking their morphologies to chemical signatures that are characteristic of life. Some represent now-extinct bacteria and microbes from a domain of life called Archaea, while others are similar to microbial species still found today. The findings also suggest how each may have survived on an oxygen-free planet.

The microfossils—so called because they are not evident to the naked eye—were first described in the journal Science in 1993 by Schopf and his team, which identified them based largely on the fossils’ unique, cylindrical and filamentous shapes. Schopf, director of UCLA’s Center for the Study of Evolution and the Origin of Life, published further supporting evidence of their biological identities in 2002.

He collected the rock in which the fossils were found in 1982 from the Apex chert deposit of Western Australia, one of the few places on the planet where geological evidence of early Earth has been preserved, largely because it has not been subjected to geological processes that would have altered it, like burial and extreme heating due to plate-tectonic activity.

But Schopf’s earlier interpretations have been disputed. Critics argued they are just odd minerals that only look like biological specimens. However, Valley says, the new findings put these doubts to rest; the microfossils are indeed biological.

“I think it’s settled,” he says.

Using a secondary ion mass spectrometer (SIMS) at UW-Madison called IMS 1280—one of just a handful of such instruments in the world—Valley and his team, including department geoscientists Kouki Kitajima and Michael Spicuzza, were able to separate the carbon composing each fossil into its constituent isotopes and measure their ratios.

Isotopes are different versions of the same chemical element that vary in their masses. Different organic substances—whether in rock, microbe or animal—contain characteristic ratios of their stable carbon isotopes.

Using SIMS, Valley’s team was able to tease apart the carbon-12 from the carbon-13 within each fossil and measure the ratio of the two compared to a known carbon isotope standard and a fossil-less section of the rock in which they were found.

“The differences in carbon isotope ratios correlate with their shapes,” Valley says. “If they’re not biological there is no reason for such a correlation. Their C-13-to-C-12 ratios are characteristic of biology and metabolic function.”

Based on this information, the researchers were also able to assign identities and likely physiological behaviors to the fossils locked inside the rock, Valley says. The results show that “these are a primitive, but diverse group of organisms,” says Schopf.

The team identified a complex group of microbes: phototrophic bacteria that would have relied on the sun to produce energy, Archaea that produced methane, and gammaproteobacteria that consumed methane, a gas believed to be an important constituent of Earth’s early atmosphere before oxygen was present.

It took Valley’s team nearly 10 years to develop the processes to accurately analyze the microfossils—fossils this old and rare have never been subjected to SIMS analysis before. The study builds on earlier achievements at WiscSIMS to modify the SIMS instrument, to develop protocols for sample preparation and analysis, and to calibrate necessary standards to match as closely as possible the hydrocarbon content to the samples of interest.

In preparation for SIMS analysis, the team needed to painstakingly grind the original sample down as slowly as possible to expose the delicate fossils themselves—all suspended at different levels within the rock and encased in a hard layer of quartz—without actually destroying them. Spicuzza describes making countless trips up and down the stairs in the department as geoscience technician Brian Hess ground and polished each microfossil in the sample, one micrometer at a time.

Each microfossil is about 10 micrometers wide; eight of them could fit along the width of a human hair.

Valley and Schopf are part of the Wisconsin Astrobiology Research Consortium, funded by the NASA Astrobiology Institute, which exists to study and understand the origins, the future and the nature of life on Earth and throughout the universe.

Studies such as this one, Schopf says, indicate life could be common throughout the universe. But importantly, here on Earth, because several different types of microbes were shown to be already present by 3.5 billion years ago, it tells us that “life had to have begun substantially earlier—nobody knows how much earlier—and confirms it is not difficult for primitive life to form and to evolve into more advanced microorganisms,” says Schopf.

Earlier studies by Valley and his team, dating to 2001, have shown that liquid water oceans existed on Earth as early as 4.3 billion years ago, more than 800 million years before the fossils of the present study would have been alive, and just 250 million years after the Earth formed.

“We have no direct evidence that life existed 4.3 billion years ago but there is no reason why it couldn’t have,” says Valley. “This is something we all would like to find out.”

UW-Madison has a legacy of pushing back the accepted dates of early life on Earth. In 1953, the late Stanley Tyler, a geologist at the university who passed away in 1963 at the age of 57, was the first person to discover microfossils in Precambrian rocks. This pushed the origins of life back more than a billion years, from 540 million to 1.8 billion years ago.

“People are really interested in when life on Earth first emerged,” Valley says. “This study was 10 times more time-consuming and more difficult than I first imagined, but it came to fruition because of many dedicated people who have been excited about this since day one … I think a lot more microfossil analyses will be made on samples of Earth and possibly from other planetary bodies.”

Volcano Erupts In Indonesia’s North Sumatra

The Sinabung volcano in Indonesia’s North Sumatra province erupted on Monday, spewing hot clouds, an official monitoring the volcano said.

Head of Sinabung volcano monitoring post Armen Putra said the latest eruption took place on 13:02 p.m. Western Indonesian Time (WIB), coupled with 303 seconds of tremors around the area.

“Hot clouds were seen rising 2,500 meters to the east-southeast and 3,500 meters to the south,” Armed said.

He added the post was hardly able to see the column of smoke and ashes from the eruption as the volcano summit was engulfed by thick haze. The wind blew mildly during the eruption, bringing the ashes to the west-south direction, he added.

People were advised to stay away from areas declared red zones around the volcano as more eruptions were expected to take place in the near future, he said.

People were also told to be remain alert for possible flood of cold lava from the volcano amid the intensifying rains nowadays.

Indonesian authorities imposed highest alert of level 4 in the volcano, which has yet to be reviewed since 2013 when it began its eruptions.

The last eruption prior to the Monday’s eruption took place on Nov. 29, blasted column of volcanic ashes and hot clouds.

Over 2,000 people were displaced from the ongoing Sinabung volcanic activities.

Mars And Earth May Not Have Been Early Neighbors

A study published in the journal Earth and Planetary Science Letters posits that Mars formed in what today is the Asteroid Belt, roughly one and a half times as far from the sun as its current position, before migrating to its present location.

The assumption has generally been that Mars formed near Earth from the same building blocks, but that conjecture raises a big question: why are the two planets so different in composition? Mars contains different, lighter, silicates than Earth, more akin to those found in meteorites. In an attempt to explain why the elements and isotopes on Mars differ widely from those on Earth, researchers from Japan, the United States and the United Kingdom ran simulations to gain insights into the Red Planet’s movement within the solar system.

Even though the study’s simulations suggested that the most probable explanation is that Mars formed near Earth, that model doesn’t account for the compositional differences between the two planets. Thus, researchers paid particular attention to simulations consistent with the so-called Grand Tack model, which suggests that Jupiter played a major role in the formation and final orbital architecture of the inner planets. The theory holds that a newly-established Jupiter plowed a large concentration of mass towards the sun, which contributed to the formation of Earth and Venus, while simultaneously pushing material away from Mars, accounting for the planet’s small mass (roughly 11 percent that of Earth) and the difference between the two planets’ compositions.

In Grand Tack simulations, the researchers gleaned additional insight into Mars’ formation. A small percentage of the simulations suggested that Mars formed much farther from the sun than it is now and that Jupiter’s gravitational pull pushed Mars into its current position.

University of Colorado Geological Sciences professor Stephen Mojzsis, a co-author of the study, isn’t concerned by the low probability of this scenario taking place.

“Low probability means one of two things: that we don’t have a better physical mechanism to explain Mars’ formation or in the enormous panoply of possibilities we ended up with one that is relatively rare,” he says, noting that the latter seems to be the best conclusion.

Mojzsis also keeps such terms in perspective. “Keep in mind that rare is relative,” when it comes to space, he says, and rare outcomes do happen. What are the chances that Earth would cross orbits with the asteroid that hit the Yucatan and rendered the dinosaurs extinct?

“Given enough time, we can expect these events,” Mojzsis says. “For example, you’ll eventually get double sixes if you roll the dice enough times. The probability is 1/36 or roughly the same as we get for our simulations of Mars’ formation.”

One implication of Mars forming farther away from the sun is that the planet would have been colder than originally thought—perhaps too cold for liquid water or to sustain life. This theory would seem to challenge the idea that Mars was once far warmer and wetter than it is now. Mojzsis argues that there’s plenty of time in Mars’ early history for it to have been both colder and farther away and at times for for it to have experienced warm, wet periods.

“Mars’ formation in the Asteroid Belt took place very early in Mars’ history, well before the crust stabilized and the atmosphere was established,” he says. In a paper he co-authored last year, Mojzsis concludes that late in Mars’ planetary formation it was bombarded by asteroids that formed the planet’s countless craters. Such large impacts could “melt the cryosphere and Mars’ crust to densify Mars’ atmosphere and to restart the hydrologic cycle,” Mojzsis says.

While many scientists are beginning to embrace the idea of planetary migration, studies such as this raise additional questions regarding the planets and their histories. What is Venus’ composition and how does it compare to that of Earth? Confirmation of similarities between Venus and Earth would circumstantially support the idea that, in the Grand Tack theory, Jupiter pushed material in-system to form Earth and Venus. It would also support researchers’ theories about the formation of planets in the inner solar system, including Mars. However, the lack of any samples, even meteorites, from Venus makes it difficult to answer that question. NASA and the Russian space agency Roscosmos have proposed the joint Venera-D mission that would send an orbiter to Venus around 2025, which may yield some clues to the planet’s composition.

Mojzsis also points out that one of the problems we face is trying to understand how the giant planets formed. Jupiter, Saturn, Uranus, and Neptune couldn’t have formed where they now reside because the Outer solar system didn’t have enough mass early on to account for these giant worlds, he says.

It could be that the giant planets formed close together and then later moved away by the influence of their gravitational interactions. Such a theory isn’t unique to our solar system. “We understand from direct observations via the Kepler Space Telescope and earlier studies that giant planet migration is a normal feature of planetary systems,” Mojzsis says. “Giant planet formation induces migration, and migration is all about gravity, and these worlds affected each other’s orbits early on.”

Mojzsis’ recent work also focuses on how Jupiter ended up in its current position and how its formation corresponds with the dispersal of gas and dust from the sun’s planet-forming disc. Little by little, scientists are gaining a greater understanding of the solar system’s history—and of the nature of planetary formation in our galactic neighborhood.

Java Earthquake Kills At Least Three People And Damages Buildings

A powerful earthquake that struck the Indonesian island of Java has killed at least three people and caused damage to hundreds of buildings.

People ran into the street in panic in many areas and Indonesian television showed heavy traffic on roads as people fled coastal areas. There were also reports that buildings had collapsed in the city of Tasikmalaya in West Java.

A 62-year-old man in Ciamis and an 80-year-old woman in Pekalongan city were killed when the buildings they were in collapsed, a national disaster mitigation agency spokesman said. A 34-year-old woman from the city of Yogyakarta died when she fell while running out of her house.

Java, Indonesia’s most densely populated island, is home to more than half of the country’s 250 million people.

The US Geological Survey said the epicentre of the magnitude-6.5 quake was located at a depth of 57 miles (92km), about 32 miles south-west of Tasikmalaya.

Indonesia’s national disaster management agency said the quake activated tsunami early warning systems in the south of Java, prompting thousands to evacuate some coastal areas, but no tsunami was detected.

Sutopo Purwo Nugroho, a spokesman for the disaster agency, said in a press briefing on Saturday that three people had been killed, seven injured and hundreds of buildings damaged, including schools, hospitals and government buildings in central and West Java.

Dozens of patients had to be helped to safety from a hospital in Banyumas and were given shelter in tents, he said.

Jakarta resident Web Warouw, 50, was on the 18th floor when the quake struck just before midnight local time (1700 GMT).

“Suddenly, we felt dizzy … We then realised it was a quake and immediately ran downstairs,” Warouw said.

The quake swayed buildings for several seconds in the capital. Some residents of high-rise apartment buildings left their properties.

About 170,000 lives were lost when a 9.1-magnitude quake and tsunami struck Aceh province in December 2004, which also hit coastal areas as far away as Somalia.

Another earthquake struck Aceh in December 2016, killing more than 100 people, injuring many others and leaving tens of thousands homeless.

Italian Volcano Stromboli Erupts

Experts have recorded high levels of seismic activity at the Stromboli volcano in the Aeolian Islands, north of Sicily.

The flurry of eruptions comes after a major explosion at the volcano on December 1, according to the Catania section of Italy’s National Institute of Geophysics and Volcanology, which monitors Stromboli.

It is accompanied by a sharp increase in infrasonic pressure.

The incredible video shows the lava as it flows from the summit and into the sea, which is being closely monitored by the INGV and Civil Defence.

A new lava flow can be seen from the volcano’s north-eastern crater on December 15.

A vent was also captured as it shot out spurts of lava, which could then be seen flowing out of the crater and down the “stream of fire”, the part of Stromboli’s northern slope scarred by centuries of eruptions.

The flow of lava has stopped, but volcanic acitivity remains at a high and access to the volcano’s highest slopes have been closed for safety.

Stromboli is one of the most active volcanoes in the world and has been erupting almost continuously since 1932.

Seen from far and wide, eruptions at night have been dubbed the “lighthouse of the Mediterranean”.

Stromboli has been in almost continuous eruption for the past 2,000 years.

It is one of the eight Aeolian Islands, a volcanic arc north of Sicily.