Mount Etna in Italy is a modern example of alkaline volcanism. Credit: Shawn Appel on Unsplash
As Europe’s most active volcano, Mount Etna is intensively monitored by scientists and Italian authorities. Satellite-based measurements have shown that the southeastern flank of the volcano is slowly sliding towards the sea, while the other slopes are largely stable. To date, it has been entirely unknown if and how movement continues under water, as satellite-based measurements are impossible below the ocean surface. With the new GeoSEA seafloor geodetic monitoring network, scientists from the GEOMAR Helmholtz Centre for Ocean Research Kiel, the Kiel University, priority research area Kiel Marine Science, and the Istituto Nazionale di Geofisica e Vulcanologia (INGV) have now been able to detect for the first time the horizontal and vertical movement of a submerged volcanic flank.
The results confirm that the entire southeastern flank is in motion. The driving force of flank movement is most likely gravity, and not the ascent of magma, as previously assumed. Catastrophic collapse involving the entire flank or large parts of it cannot be excluded and would trigger a major tsunami with extreme effects in the region. The results of the study have been published today in the international journal Science Advances.
“At Mount Etna we used a sound based underwater geodetic monitoring network, the so-called marine geodesy, on a volcano for the first time ,” says Dr. Morelia Urlaub, lead author of the study. She led the investigations as part of the “MAGOMET — Marine geodesy for offshore monitoring of Mount Etna” project. In April 2016, the GEOMAR team placed a total of five acoustic monitoring transponder stations across the fault line that represents the boundary between the sliding flank and the stable slope. “We placed three on the sliding sector and two on the presumably stable side of the fault line,” says Dr. Urlaub.
During their mission each transponder was sending an acoustic signal every 90 minutes. Since the speed of sound in water is known, the travel time of the signals between transponders gave information on the distances between transponders on the seafloor with a precision of less than one centimeter. “We noticed that in May 2017 the distances between transponders on different sides of the fault clearly changed. The flank slipped by four centimeters seawards and subsided by one centimeter within a period of eight days,” explains Dr. Urlaub. This movement can be compared to a very slow earthquake, a so-called “slow slip event.” It was the first time that the horizontal movement of such a slow slip event was recorded under water. In total, the system delivered data for about 15 months.
A comparison with ground deformation data obtained by satellite showed that the southeastern flank above sea level moved by a similar distance during the same observation period. “So the entire southeast flank changed its position,” says Dr. Urlaub.
“Overall, our results indicate that the slope is sliding due to gravity and not due to the rise of magma,” she continues. If magma dynamics in the centre of the volcano triggered flank deformation, displacement of the flank would be expected to be larger onshore than below water. This is crucial for hazard assessments. “The entire slope is in motion due to gravity. It is therefore quite possible that it could collapse catastrophically, which could trigger a tsunami in the entire Mediterranean,” explains Professor Heidrun Kopp, coordinator of the GeoSEA array and co-author of the study. However, the results of the study do not allow a prediction whether and when such an event might occur.
“Further basic research is needed to understand the geological processes at and around Etna and other coastal volcanoes. Our investigation shows that the sound-based geodetic monitoring network can be a tremendous help in this respect,” summarises Dr. Urlaub.
Reference:
Morelia Urlaub, Florian Petersen, Felix Gross, Alessandro Bonforte, Giuseppe Puglisi, Francesco Guglielmino, Sebastian Krastel, Dietrich Lange, Heidrun Kopp. Gravitational collapse of Mount Etna’s southeastern flank. Science Advances, 2018; 4 (10): eaat9700 DOI: 10.1126/sciadv.aat9700
Etna eruption, Catania, Sicily. Credit: Wead / Fotolia
To figure out where magma gathers in the earth’s crust and for how long, Vanderbilt University volcanologist Guilherme Gualda and his students traveled to their most active cluster: the Taupo Volcanic Zone of New Zealand, where some of the biggest eruptions of the last 2 million years occurred — seven in a period between 350,000 and 240,000 years ago.
After studying layers of pumice visible in road cuts and other outcrops, measuring the amount of crystals in the samples and using thermodynamic models, they determined that magma moved closer to the surface with each successive eruption.
The project fits into Gualda’s ongoing work studying supereruptions — how the magma systems that feed them are built and how the Earth reacts to repeated input of magma over short periods of time.
“As the system resets, the deposits become shallower,” said Gualda, associate professor of earth and environmental sciences. “The crust is getting warmer and weaker, so magma can lodge itself at shallower levels.”
What’s more, the dynamic nature of the Taupo Volcanic Zone’s crust made it more likely for the magma to erupt than be stored in the crust. The more frequent, smaller eruptions, which each produced 50 to 150 cubic kilometers of magma, likely prevented a supereruption. Supereruptions produce more than 450 cubic kilometers of magma and they affect the earth’s climate for years following the eruption.
“You have magma sitting there that’s crystal-poor, melt-rich for few decades, maybe 100 years, and then it erupts,” Gualda said. “Then another magma body is established, but we don’t know how gradually that body assembles. It’s a period in which you’re increasing the amount of melt in the crust.”
The question that remains is how long it look for these crystal-rich magma bodies to assemble between eruptions. It could be thousands of years, Gualda said, but he believes it’s shorter than that.
Reference:
Guilherme A. R. Gualda, Darren M. Gravley, Michelle Connor, Brooke Hollmann, Ayla S. Pamukcu, Florence Bégué, Mark S. Ghiorso, Chad D. Deering. Climbing the crustal ladder: Magma storage-depth evolution during a volcanic flare-up. Science Advances, 2018; 4 (10): eaap7567 DOI: 10.1126/sciadv.aap7567
This is a virtual rendering of the Visogliano and Fontana Ranuccio teeth. Credit: Zanolli et al., 2018 CC-BY – Redistribution allowed with credit.
Fossil teeth from Italy, among the oldest human remains on the Italian Peninsula, show that Neanderthal dental features had evolved by around 450,000 years ago, according to a study published October 3, 2018 in the open-access journal PLOS ONE by Clément Zanolli of the Université Toulouse III Paul Sabatier in France and colleagues. These teeth also add to a growing picture of a period of complex human evolution that we are only beginning to understand.
Zanolli and colleagues examined dental remains from the sites of Fontana Fanuccio, located 50km southeast of Rome, and Visogliano, located 18km northwest of Trieste. At around 450,000 years old, these teeth join a very short list of fossil human remains from Middle Pleistocene Europe. Using micro-CT scanning and detailed morphological analyses, the authors examined the shape and arrangement of tooth tissues and compared them with teeth of other human species. They found that the teeth of both sites share similarities with Neanderthals and are distinct from modern humans.
There has been much debate over the identities and relationships of Middle Pleistocene ancient humans in Eurasia. The discovery of Neanderthal-like teeth so early in the record adds support to the suggestion of an early divergence of the Neanderthal lineage from our own, around the Early-Middle Pleistocene transition. The teeth are also notably different from other teeth known from this time in Eurasia, suggesting that there may have been multiple human lineages populating the region at this time, adding to a growing list of evidence that the Middle Pleistocene was a time of more complex human evolution than previously recognized.
Zanolli adds: “The remains from Fontana Ranuccio and Visogliano represent among the oldest human fossil remains testifying to a peopling phase of the Italian Peninsula. Our analyses of the tooth internal structural organization reveal a Neanderthal-like signature, also resembling the condition shown by the contemporary assemblage from Atapuerca Sima de los Huesos, indicating that an overall Neanderthal morphological dental template was preconfigured in Western Europe at least 430 to 450 ka ago.”
Reference:
Clément Zanolli, María Martinón-Torres, Federico Bernardini, Giovanni Boschian, Alfredo Coppa, Diego Dreossi, Lucia Mancini, Marina Martínez de Pinillos, Laura Martín-Francés, José María Bermúdez de Castro, Carlo Tozzi, Claudio Tuniz, Roberto Macchiarelli. The Middle Pleistocene (MIS 12) human dental remains from Fontana Ranuccio (Latium) and Visogliano (Friuli-Venezia Giulia), Italy. A comparative high resolution endostructural assessment. PLOS ONE, 2018; 13 (10): e0189773 DOI: 10.1371/journal.pone.0189773
Note: The above post is reprinted from materials provided by PLOS.
Earth’s mantle (dark red) lies below the crust (brown layer near the surface) and above the outer core (bright red). Credit: CC image by Argonne National Laboratory via Flickr
Researchers at CU Boulder report that they may have solved a geophysical mystery, pinning down the likely cause of a phenomenon that resembles a wrench in the engine of the planet.
In a study published today in Nature Geoscience, the team explored the physics of “stagnant slabs.” These geophysical oddities form when huge chunks of Earth’s oceanic plates are forced deep underground at the edges of certain continental plates. The chunks sink down into the planet’s interior for hundreds of miles until they suddenly — and for reasons scientists can’t explain — stop like a stalled car.
CU Boulder’s Wei Mao and Shijie Zhong, however, may have found the reason for that halt. Using computer simulations, the researchers examined a series of stagnant slabs in the Pacific Ocean near Japan and the Philippines. They discovered that these cold rocks seem to be sliding on a thin layer of weak material lying at the boundary of the planet’s upper and lower mantle — roughly 660 kilometers, or 410 miles, below the surface.
And the stoppage is likely temporary: “Although we see these slabs stagnate, they are a fairly recent phenomena, probably happening in the last 20 million years,” said Zhong, a co-author of the new study and a professor in CU Boulder’s Department of Physics.
The findings matter for tectonics and volcanism on the Earth’s surface. Zhong explained that the planet’s mantle, which lies above the core, generates vast amounts of heat. To cool the globe down, hotter rocks rise up through the mantle and colder rocks sink.
“You can think of this mantle convection as a big engine that drives all of what we see on Earth’s surface: earthquakes, mountain building, plate tectonics, volcanos and even Earth’s magnetic field,” Zhong said.
The existence of stagnant slabs, which geophysicists first located about a decade ago, however, complicates that metaphor, suggesting that Earth’s engine may grind to a halt in some areas. That, in turn, may change how scientists think diverse features, such as East Asia’s roiling volcanos, form over geologic time.
Scientists have mostly located such slabs in the western Pacific Ocean, specifically off the east coast of Japan and deep below the Mariana Trench. They occur at the sites of subduction zones, or areas where oceanic plates at the surface of the planet plunge hundreds of miles below ground.
Slabs seen at similar sites near North and South America behave in ways that geophysicists might expect: They dive through Earth’s upper mantle and into the lower mantle where they heat up near the core.
But around Asia, “they simply don’t go down,” Zhong said. Instead, the slabs spread out horizontally near the boundary between the upper and lower mantle, a point at which heat and pressure inside Earth cause minerals to change from one phase to another.
To find out why slabs go stagnant, Zhong and Mao, a graduate student in physics, developed realistic simulations of how energy and rock cycle around the entire planet.
They found that the only way they could explain the behavior of the stagnant slabs was if a thin layer of less-viscous rock was wedged in between the two halves of the mantle. While no one has directly observed such a layer, researchers have predicted that it exists by studying the effects of heat and pressure on rock.
If it does, such a layer would act like a greasy puddle in the middle of the planet. “If you introduce a weak layer at that depth, somehow the reduced viscosity helps lubricate the region,” Zhong said. “The slabs get deflected and can keep going for a long distance horizontally.”
Stagnant slabs seem to occur off the coast of Asia, but not the Americas, because the movement of the continents above gives those chunks of rock more room to slide. Zhong, however, said that he doesn’t think the slabs will stay stuck. With enough time, he suspects that they will break through the slick part of the mantle and continue their plunge toward the planet’s core.
The planet, in other words, would still behave like an engine — just with a few sticky spots. “New research suggests that the story may be more complicated than we previously thought,” Zhong said.
Reference:
Wei Mao, Shijie Zhong. Slab stagnation due to a reduced viscosity layer beneath the mantle transition zone. Nature Geoscience, 2018; DOI: 10.1038/s41561-018-0225-2
New research led by Victoria University of Wellington geophysicist Associate Professor Simon Lamb and published in Nature Geoscience has revealed how understanding the events leading up to the 2016 Kaikōura Earthquake may lead to a different approach to forecasting earthquakes.
“It has been commonly thought that the best way to predict future earthquakes is to analyse the earthquake histories of individual faults,” says Associate Professor Lamb. “Data about past earthquakes are entered into modelling software and used to predict future earthquakes on each fault. This method assumes that each fault has its own in-built pacemaker or driving mechanism, giving rise to semi-regular earthquakes on the fault.”
Associate Professor Lamb thinks there are a number of issues with this method.
“It is impractical to characterise every fault—there are just too many and some are not visible at the surface,” he says.
But a more fundamental issue with this method was revealed by analysis done in conjunction with Associate Professor Richard Arnold of Victoria University of Wellington and Dr. James Moore at the Nanyang Technical University, Singapore. Associate Professor Lamb says the team’s work showed that, in most cases, the earthquakes that happen on faults are triggered by earthquakes on faults elsewhere.
To come to this conclusion, the team looked at the slow movements of the landscape in the two decades prior to the 2016 Kaikōura earthquake, measured very precisely with satellite mapping of ground motions.
“We found that the measured ground motions were caused by slippage only on the single major fault separating the two tectonic plates that lie under New Zealand. This large fault, called the megathrust, underlies much of New Zealand, and only reaches the surface offshore.”
The megathrust moves freely at depths of 30 kilometres or more, but at shallower depths it is locked in place. This combination of steady movement in some places and no movement in others slowly forces the southern North Island and northern South Island to bend like a piece of elastic. Associate Professor Lamb says that this movement puts extreme stress on the landscape, and that this was the cause of the 2016 Kaikōura quake.
“The Kaikōura earthquake initiated a complex pattern of fault movement, essentially shattering the landscape, and causing a cascade of earthquakes on 20 or more faults,” Associate Professor Lamb says. “The data we studied show a strong link between the pattern of shattering and locking of the underlying megathrust prior to the earthquake and the movement during the earthquake itself. The damage caused by the Kaikōura earthquake runs parallel to this locking of the megathrust, but cuts across many of the big surface faults in the area, indicating a strong link to the movement of the megathrust rather than any of the individual faults.”
These findings may be significant for the way we predict future earthquakes, Associate Professor Lamb says.
“While we may not be able to predict the movement of individual faults, we can track the underlying cause of an earthquake and give an indication of where future shaking might occur by understanding and modelling the megathrust.”
Reference:
Simon Lamb et al. Locking on a megathrust as a cause of distributed faulting and fault-jumping earthquakes, Nature Geoscience (2018). DOI: 10.1038/s41561-018-0230-5
The Hunga Island Tonga Hunga Ha’apai or HTHH emerged in 2015 after the eruption of a submarine volcano in the Pacific Ocean. Credit: Pixabay
Mountains are among the most biodiverse places on Earth, but scientists have struggled to fully understand why they are so important in creating high species richness. An international research team, including four scientists from the University of Amsterdam, has now shed new light on answering this long-standing question.
The team found that mountain building, through a process of uplift and erosion, continuously reshapes the landscape and is responsible for creating habitat heterogeneity in an elevational gradient. “The complex interplay between growing mountains and climate generates plenty of opportunities for the creation of new species,” says Carina Hoorn, senior author of the paper. “Although climate and ruggedness of the terrain were previously thought to be the principal cause for mountain biodiversity, our global synthesis now makes clear that geological history plays a paramount role in this process,” explains Hoorn.
The team reached this conclusion by applying statistical models to biological, geological and climatological datasets from across the globe. “In our models, we related the species richness of birds, mammals and amphibians to global datasets of temperature, precipitation, erosion rates, relief and soil composition,” says Daniel Kissling who conducted the statistical analyses of the paper. “I was surprised to find not only the usual correlations with climate, but a significant relation between biodiversity, erosion history, relief and number of soil types,” continues Kissling. While the study shows that this is evident globally, it also revealed that the relationship can vary depending on which mountain system is considered. “This regional variation in the importance of geological drivers was really unexpected,” says Kissling.
The study further showed that geographic position (e.g. whether a mountain intercepts atmospheric currents or not) and the duration of mountain building process (young or old) are also important processes influencing biodiversity in mountains. On shorter geological time scales, Quaternary climatic fluctuations can also promote the creation of new species in mountains. “We suggests that the waxing and waning of glaciers, which has strongly reshaped the landscape and repeatedly connected and disconnected animal and plant populations, has played an important role for the creation of new mountain species,” says Suzette Flantua who studied the effects of Quaternary climate change on mountain biodiversity in Latin America for her Ph.D. at the University of Amsterdam.
The advances in geological methods and the increasingly complete global data sets on climate, soils, erosion history, and species richness only now have made it possible to gain such comprehensive insights into the relation between mountain building and biodiversity. The scientists are optimistic that with the new methods and datasets, further insights into the complex relationship between biodiversity, climate and mountain building can be expected in the near future.
Reference:
Alexandre Antonelli et al. Geological and climatic influences on mountain biodiversity, Nature Geoscience (2018). DOI: 10.1038/s41561-018-0236-z
The genus Vibrio is one of the best model marine heterotrophic bacterial groups, and many Vibrio species grow very quickly with short generation times. In addition, many Vibrio spp. are well-known bacterial pathogens, causing disease in humans or marine animals. For example, Vibrio cholerae is the causative agent of cholera. Over the past 40 years, many nonpathogenic species of Vibrio have also been described.
Vibrios are ubiquitous in estuarine and marine environments on a global scale, especially in coastal areas. They are easily cultured on standard or selective media and are capable of a diverse array of metabolic activities. Also, vibrios are capable of responding rapidly to nutrient pulses with explosive growth responses in amended microcosms, such as during phytoplankton blooms and dust storms, suggesting that the short period of Vibrio blooms should be considered when attempting to determine their overall contribution to the recycling of organic macromolecules. Currently, the role of Vibrio spp. in marine organic carbon cycling, particularly in coastal environments, is underestimated.
In an article coauthored by Xiao-Hua Zhang, Heyu Lin, Xiaolei Wang and Brian Austin, scholars at College of Marine Life Sciences, Ocean University of China, and the Institute of Aquaculture, University of Stirling, U.K., provided an overview of distribution and environmental drivers of Vibrio populations in the marine environment, and discussed their potential role in marine organic carbon cycling.
These four scholars proposed in the study, which was published in Science China, that “Vibrio spp. may exert large impacts on marine organic carbon cycling especially in marginal seas.” In addition, they proposed a potential action mode of Vibrio species in marine organic carbon cycling (Figure 1).
“All currently described Vibrio spp. are obligate heterotrophs and, as such, rely on organic matter for their carbon sources. Generally, vibrios consume a wide array of organic carbon compounds as carbon and energy sources, with most species being able to utilize over 40 compounds. Many of the polysaccharides are derived from macroalgal cell walls (i.e., alginic acid, agar, fucoidan and laminarin) or zooplankton exoskeletons (i.e., chitin). In our previous work, 56.8 percent of Vibrio cultures (330 out of 581 isolates) isolated from Chinese marginal seas possessed chitin, while 11.2 percent of Vibrio cultures (65 out of 581 isolates) could degrade alginic acid (data not shown). Vibrios are able to engage in both respiratory and fermentative metabolism and transform organic carbon into cell material and the waste products of energy metabolism. During aerobic or anaerobic respiration, large amounts of metabolic end products are excreted. Hence, Vibrio spp. are undoubtedly key players in marine organic carbon cycles, especially in marginal seas,” the authors write.
Reference:
Xiaohua Zhang et al, Significance of Vibrio species in the marine organic carbon cycle—A review, Science China Earth Sciences (2018). DOI: 10.1007/s11430-017-9229-x
Note: The above post is reprinted from materials provided by Science China Press.
The calcium carbonate skeleton of this living brain coral (Diploria labyrinthiformis) was evaluated for this study. From the coral, which is about one meter in diameter, the researchers extracted a small section of the skeleton without harming the coral. Credit: Photo courtesy of the researchers.
When nitrogen-based fertilizers flow into water bodies, the result can be deadly for marine life near shore, but what is the effect of nitrogen pollution far out in the open ocean?
A 130-year-old brain coral has provided the answer, at least for the North Atlantic Ocean off the East Coast of the United States. By measuring the nitrogen in the coral’s skeleton, a team of researchers led by Princeton University found significantly less nitrogen pollution than previously estimated. The study was published online in the Proceedings of the National Academy of Sciences.
“To our surprise, we did not see evidence of increased nitrogen pollution in the North Atlantic Ocean over the past several decades,” said Xingchen (Tony) Wang, who conducted the work as part of his doctorate in geosciences at Princeton and is now a postdoctoral scholar at the California Institute of Technology.
Earlier work by the Princeton-based team, however, did find elevated nitrogen pollution in another open ocean site in the South China Sea, coinciding with the dramatic increase in coal production and fertilizer usage in China over the past two decades.
In the new study, the researchers looked at coral skeleton samples collected in the open ocean about 620 miles east of the North American continent near the island of Bermuda, a region thought to be strongly influenced by airborne nitrogen released from U.S. mainland sources such as vehicle exhaust and power plants.
Although the team found no evidence that human-made nitrogen was on the rise, the researchers noted variations in nitrogen that corresponded to levels expected from a natural climate phenomenon called the North Atlantic Oscillation, Wang said.
The result is in contrast to previously published computer models that predicted a significant increase in human-made nitrogen pollution in the North Atlantic.
The work may indicate that U.S. pollution control measures are successfully limiting the amount of human-generated nitrogen emissions that enter the ocean.
“Our finding has important implications for the future of human nitrogen impact on the North Atlantic Ocean,” said Wang. “Largely due to advances in pollution technology, human nitrogen emissions from the U.S. have held steady or even declined in recent decades,” he said. “If emissions continue at this level, our results imply that the open North Atlantic will remain minimally affected by nitrogen pollution in coming decades.”
Nitrogen, when in its biologically available form and supplied in excess, can cause overgrowth of plants and algae and lead to severe ecosystem harm, including marine “dead zones” that form when microorganisms consume all the oxygen in the water, leaving none for fish. Fertilizer production and fossil fuel burning have greatly increased the production of biologically available, or “fixed,” nitrogen since the early 20th century.
When emitted to the atmosphere, fixed nitrogen can influence the ocean far from land. However, the impacts on the ocean are difficult to study because of the challenges involved in making long-term observations in the open ocean.
Corals can help. Stony or “Scleractinian” corals are long-lived organisms that build a calcium carbonate skeleton as they grow. The corals soak up nitrogen from the surrounding water and deposit a small portion in their skeletons. The skeletons provide a natural record of nitrogen emissions.
To distinguish human-made, or anthropogenic, nitrogen from the naturally occurring kind, the researchers take advantage of the fact that nitrogen comes in two weights. The heavier version, known as 15N, contains one more neutron than the lighter 14N. Anthropogenic nitrogen has a lower ratio of 15N to 14N than does the nitrogen in the ocean.
“It has long been my dream to use the nitrogen in coral skeletons to reconstruct past environmental changes; thanks to Tony, we are now doing it,” said Daniel Sigman, the Dusenbury Professor of Geological and Geophysical Sciences at Princeton.
While a graduate student at Princeton, Wang developed a sensitive and precise method to measure the 15N-to-14N ratio using a mass spectrometer, which is like a bathroom scale for weighing molecules.
To collect coral samples in the North Atlantic Ocean, Wang and Anne Cohen, an associate scientist in geology and geophysics at Woods Hole Oceanographic Institution, led a team in 2014 to Bermuda. The investigators removed a 23-inch-long core from a living brain coral (Diploria labyrinthiformis) about 10 feet below the surface on Hog Reef, about six miles from the main island. The researchers confirmed that Bermuda’s nitrogen run-off was not a factor at the site by measuring nitrogen levels in plankton floating nearby.
In addition to Wang, Cohen and Sigman, the research featured contributions from Princeton graduate student in geosciences Victoria Luu, Haojia Ren of National Taiwan University, Zhan Su of Caltech, and Gerald Haug of the Max Planck Institute for Chemistry.
This work was supported by the National Science Foundation and Princeton University’s Grand Challenges Program.
The study, “Natural forcing of the North Atlantic nitrogen cycle in the Anthropocene,” by Xingchen Tony Wang, Anne Cohen, Victoria Luu, Haojia Ren, Zhan Su, Gerald Haug and Daniel Sigman, was published online the week of October 1, 2018 in the Proceedings of the National Academy of Sciences.
Note: The above post is reprinted from materials provided by Princeton University. Original written by Catherine Zandonella.
Seismogram being recorded by a seismograph at the Weston Observatory in Massachusetts, USA. Credit: Wikipedia
Accurate monitoring of the ground beneath our feet for signs of seismic activity to identify natural phenomena such as earthquakes, volcanic eruptions and the leakage of fluids stored deep underground remains challenging.
Time-lapse 4-dimensional seismic monitoring surveys that employ an active seismic source can accurately map the subsurface, and comparing results from different surveys can show how fluids (such as carbon dioxide, CO2) move in deep geological reservoirs. However, the expense of such surveys limits how often data can be gathered meaning that subsequent analysis often has poor temporal resolution. An alternative that provides a continuous dataset is the passive monitoring of ambient seismic noise, but the accuracy of this approach depends on the ambient sources, which can change over time.
In an article recently published in Geophysics, a team of researchers from Kyushu University and industrial and governmental representatives from Japan and Canada report a new method for accurately monitoring the shallow subsurface at a high spatiotemporal resolution. The method was developed using data from 2014 to 2016 that was collected from the Accurately Controlled Routinely Operated Signal System (ACROSS) located at the Aquistore CO2 storage site in Saskatchewan, Canada.
Obtaining a high-resolution characterization of the shallow subsurface has previously been held back by the limited number of ACROSS units, however the researchers were able to overcome this obstacle. As the lead author Tatsunori Ikeda explains: “applying spatially windowed surface-wave analysis allowed us to study the spatial variation of surface wave velocities using data from a single ACROSS unit.”
The research team validated their method against data gathered from hundreds of geophone measuring devices located around the ACROSS unit and a computational model of the site. Their analysis of the surface waves shows spatial variation in the surface wave velocities, and the impact of seasonal weather on these velocities. Confirmation of the method’s accuracy highlights its potential to identify changes in the shallow subsurface that may be caused by natural phenomena or fluids leaking from storage sites much deeper underground.
As well as drawing together experts from a variety of organizations in Japan and Canada, the publication represents another step forward for researchers in Kyushu University’s International Institute for Carbon-Neutral Energy Research (I2CNER). As co-author Takeshi Tsuji notes: “The approach contributes to our ongoing work in Kyushu University to develop a downsized, continuous and controlled seismic monitoring system.” The researchers have been operating the downsized monitoring system at the Kuju geothermal and volcanological research station on Japan’s Kyushu Island.
Reference:
Tatsunori Ikeda, Takeshi Tsuji, Masashi Nakatsukasa, Hideaki Ban, Ayato Kato, Kyle Worth, Don White, Brian Roberts. Imaging and monitoring of the shallow subsurface using spatially windowed surface-wave analysis with a single permanent seismic source. Geophysics, 2018; DOI: 10.1190/GEO2018-0084.1
Diamond is a solid form of carbon with a diamond cubic crystal structure. At room temperature and pressure it is metastable and graphite is the stable form, but diamond almost never converts to graphite. Diamond is renowned for its superlative physical qualities, most of which originate from the strong covalent bonding between its atoms. In particular, it has the highest hardness and thermal conductivity of any bulk material. Those properties determine the major industrial applications of diamond in cutting and polishing tools and the scientific applications in diamond knives and diamond anvil cells.
Because of its extremely rigid lattice, diamond can be contaminated by very few types of impurities, such as boron and nitrogen. Small amounts of defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (lattice defects), green (radiation exposure), purple, pink, orange or red. Diamond also has relatively high optical dispersion (ability to disperse light of different colors).
Chemical Formula: C Locality: Kimberly, republic of South Africa. India. Brazil. Ural Mountains, Russia. Murfreesboro, Arkansas, USA. Name Origin: From the Greek, adamas, meaning “invincible” or “hardest.”
In mineralogy, diamond is a metastable allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice.
Emerald is a gemstone and a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium and sometimes vanadium. Beryl has a hardness of 7.5–8 on the Mohs scale. Most emeralds are highly included, so their toughness (resistance to breakage) is classified as generally poor.
The word “Emerald” is derived (via Old French: Esmeraude and Middle English: Emeraude), from Vulgar Latin: Esmaralda/Esmaraldus, a variant of Latin Smaragdus, which originated in Greek: σμάραγδος (smaragdos; “green gem”).
Sapphire gemstones, up to 2.59 carats, from Kimmirut. Photo courtesy of True North Gems Inc.
Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide (α-Al2O3) with trace amounts of elements such as iron, titanium, chromium, copper, or magnesium. It is typically blue, but natural “fancy” sapphires also occur in yellow, purple, orange, and green colors; “parti sapphires” show two or more colors. The only color that sapphire cannot be is red – as red colored corundum is called ruby, another corundum variety.
Pink colored corundum may be either classified as ruby or sapphire depending on locale. Commonly, natural sapphires are cut and polished into gemstones and worn in jewelry. They also may be created synthetically in laboratories for industrial or decorative purposes in large crystal boules. Because of the remarkable hardness of sapphires – 9 on the Mohs scale (the third hardest mineral, after diamond at 10 and moissanite at 9.5) – sapphires are also used in some non-ornamental applications, such as infrared optical components, high-durability windows, wristwatch crystals and movement bearings, and very thin electronic wafers, which are used as the insulating substrates of very special-purpose solid-state electronics (especially integrated circuits and GaN-based LEDs).
Ruby
Corundum ruby, 17.30 g, crystal in calcite, from Kyauksaung, Myanmar. Gift of William F. Larson.
A ruby is a pink to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide). Other varieties of gem-quality corundum are called sapphires. Ruby is one of the traditional cardinal gems, together with amethyst, sapphire, emerald, and diamond. The word ruby comes from ruber, Latin for red. The color of a ruby is due to the element chromium.
The quality of a ruby is determined by its color, cut, and clarity, which, along with carat weight, affect its value. The brightest and most valuable shade of red called blood-red or pigeon blood, commands a large premium over other rubies of similar quality. After color follows clarity: similar to diamonds, a clear stone will command a premium, but a ruby without any needle-like rutile inclusions may indicate that the stone has been treated. Ruby is the traditional birthstone for July and is usually more pink than garnet, although some rhodolite garnets have a similar pinkish hue to most rubies. The world’s most valuable ruby is the Sunrise Ruby.
Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness. Among the natural gems only moissanite and diamond are harder, with diamond having a Mohs hardness of 10.0 and moissanite falling somewhere in between corundum (ruby) and diamond in hardness. Sapphire, ruby, and pure corundum are α-alumina, the most stable form of Al2O3, in which 3 electrons leave each aluminum ion to join the regular octahedral group of six nearby O2− ions; in pure corundum this leaves all of the aluminum ions with a very stable configuration of no unpaired electrons or unfilled energy levels, and the crystal is perfectly colorless.
Taaffeite
Taaffeite
Taaffeite is a mineral, named after its discoverer Richard Taaffe (1898–1967) who found the first sample, a cut and polished gem, in October 1945 in a jeweler’s shop in Dublin, Ireland. As such, it is the only gemstone to have been initially identified from a faceted stone. Most pieces of the gem, prior to Taaffe, had been misidentified as spinel. For many years afterwards, it was known only in a few samples, and it is still one of the rarest gemstone minerals in the world.
Since 2002, the International Mineralogical Association-approved name for taaffeite as a mineral is magnesiotaaffeite-2N’2S.
Taaffe bought a number of precious stones from a jeweller in October 1945. Upon noticing inconsistencies between the taaffeite and spinels, Taaffe sent some examples to B. W. Anderson of the Laboratory of the London Chamber of Commerce for identification on 1 November 1945. When Anderson replied on 5 November 1945, he told Taaffe that they were unsure of whether it was a spinel or something new; he also offered to write it up in Gemologist.
In 1951, chemical and X-ray analysis confirmed the principal constituents of taaffeite as beryllium, magnesium and aluminium, making taaffeite the first mineral to contain both beryllium and magnesium as essential components.
The confusion between spinel and taaffeite is understandable as certain structural features are identical in both. Anderson et al., classified taaffeite as an intermediate mineral between spinel and chrysoberyl. Unlike spinel, taaffeite displays the property of double refraction that allows distinction between these two minerals.
Because of its rarity, taaffeite is used only as a gemstone.
Poudretteite
Poudretteite
Poudretteite is an extremely rare mineral and gemstone that was first discovered as minute crystals in Mont St. Hilaire, Quebec, Canada, during the 1960s. The mineral was named for the Poudrette family because they operated a quarry in the Mont St. Hilaire area where poudretteite was originally found.
Chemical Formula: KNa2B3Si12O30 Locality: From Mont Saint-Hilaire, Quebec, Canada. Name Origin: Named for the Poudrette family, operators of the quarry where type material was discovered.
This 0.86 ct gray musgravite displays an unusual iridescent phenomenon that is clearly visible in the table facet. Photo by Kevin Schumacher.
Musgravite or magnesiotaaffeite-6N’3S (chemical formula of Be(Mg, Fe, Zn)2Al6O12)
, is a rare oxide mineral. It is used as a gemstone. Its type locality is the Ernabella Mission, Musgrave Ranges, South Australia for which it was named. It is a member of the taaffeite family of minerals. Its hardness is 8 to 8.5 on the Mohs scale.
The alexandrite variety displays a color change (alexandrite effect) dependent upon the nature of ambient lighting. Alexandrite effect is the phenomenon of an observed color change from greenish to reddish with a change in source illumination. Alexandrite results from small scale replacement of aluminium by chromium ions in the crystal structure, which causes intense absorption of light over a narrow range of wavelengths in the yellow region (580 nm) of the visible light spectrum. Because human vision is more sensitive to light in the green spectrum and the red spectrum, alexandrite appears greenish in daylight where a full spectrum of visible light is present and reddish in incandescent light which emits less green and blue spectrum. This color change is independent of any change of hue with viewing direction through the crystal that would arise from pleochroism.
Alexandrite from the Ural Mountains in Russia can be green by daylight and red by incandescent light. Other varieties of alexandrite may be yellowish or pink in daylight and a columbine or raspberry red by incandescent light.
Stones that show a dramatic color change and strong colors (e.g. red-to-green) are rare and sought-after, but stones that show less distinct colors (e.g. yellowish green changing to brownish yellow) may also be considered alexandrite by gem labs such as the Gemological Institute of America.
According to a popular but controversial story, alexandrite was discovered by the Finnish mineralogist Nils Gustaf Nordenskiöld (1792–1866), and named alexandrite in honor of the future Tsar Alexander II of Russia. Nordenskiöld’s initial discovery occurred as a result of an examination of a newly found mineral sample he had received from Perovskii, which he identified as emerald at first. The first emerald mine had been opened in 1831.
Alexandrite 5 carats (1,000 mg) and larger were traditionally thought to be found only in the Ural Mountains, but have since been found in larger sizes in Brazil. Other deposits are located in India (Andhra Pradesh), Madagascar, Tanzania and Sri Lanka. Alexandrite in sizes over three carats are very rare.
5.4Ct World Rare Grandidierite High Quality Gems for Collection IGCRGD05. Credit: Gem Rock Auctions
Grandidierite is an extremely rare mineral and gem that was first discovered in 1902 in southern Madagascar. The mineral was named in honor of French explorer Alfred Grandidier (1836–1912) who studied the natural history of Madagascar.
A fossil Leggadina webbi jaw from the cavers’ explorations. Credit: Image courtesy of University of Queensland
The fossils of two extinct mice species have been discovered in caves in tropical Queensland by University of Queensland scientists tracking environment changes.
Fossils of Webb’s short-tailed mouse (Leggadina webbi) were found at Mount Etna near Rockhampton, while Irvin’s short-tailed mouse (Leggadina irvini), was discovered near Chillagoe at the base of Cape York Peninsula.
Dr Jonathan Cramb from UQ’s School of Earth and Environmental Sciences said the finds show that analysing fossils found in caves could help determine how the local environment had changed over time.
“Caves are great places for the preservation of fossils, partially because they’re natural traps that animals fall into, but also because they’re roosting sites for owls and other flying predators,” he said.
“Owls are exceptionally good at catching small mammals in particular, so the cave floor beneath their roosts is littered with the bones of rodents and small marsupials.
“The accumulation of bones build up over time, providing us with a record of what species were living in the local area, which can stretch back hundreds of thousands of years.
“Many species are only found in certain habitats — for example, hopping mice (Notomys spp.) generally live in deserts, while tree mice (Pogonomys spp.) only live in rainforests — so changes in the fauna tell us about changes in the environment.”
Dr Cramb said the team, including UQ’s Dr Gilbert Price and alumnus Scott Hocknull from the Queensland Museum, was able to confirm a number of environmental changes thanks to the fossils.
“Our findings show that the caves around Mount Etna had gone through a period of local extinction of rainforests, which were replaced by dry to arid habitats less than 280,000 years ago,” Dr Cramb said.
“My colleagues and I wondered if the same environmental change happened elsewhere in Queensland, which is why we were searching the caves near Chillagoe.
“Our analysis of fossils from the caves in north-east Queensland has shown that rainforest extinction was widespread.
“This research shows that, at least in these instances, rainforest extinction is correlated with a sudden shift in climate — a warning that rainforests are particularly vulnerable to climate change.”
The new species of mice were named after UQ palaeontologist Professor Gregory Webb and citizen scientist and caving guide Douglas Irvin.
Reference:
Jonathan Cramb, Gilbert J. Price, Scott A. Hocknull. Short-tailed mice with a long fossil record: the genus Leggadina (Rodentia: Muridae) from the Quaternary of Queensland, Australia. PeerJ, 2018; 6: e5639 DOI: 10.7717/peerj.5639
The inclusion of euconodonts in the vertebrates, or even craniates, is still controversial. Admittedly, the tissue structure of the “conodonts” (i.e; the denticles situated in their mouth; left) is at odds with conventional vertebrate hard tissues. Nevertheless, the eyes, body shape, and tail stucture of the euconodonta are strikingly vertebrate-like. After Purnell et al. 1995. Credit: Tree of Life Web Project/Wikimedia Commons.
The earliest predators appeared on Earth 480 million years ago—and they even had teeth capable of repairing themselves. A team of palaeontologists led by Bryan Shirley and Madleen Grohganz from the Chair for Palaeoenviromental Research at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have discovered more about how these organisms were able to grow and regenerate their teeth. The results have now been published in Proceedings of the Royal Society B.
Millions of years ago: A fast-moving predator with sharp teeth goes hunting in the prehistoric sea. It spies prey and advances stealthily. It goes in for the kill and devours its prey. Some of the predator’s teeth break, but they will grow back.
This is a description of a conodont. Although these eel-like vertebrates were only a few centimetres long, they are considered the Earth’s first predators. Their small teeth, which are among the most important microfossils, could repair themselves after being damaged. How, exactly, this happened is difficult to ascertain—although the fossilised teeth are often found in marine rock, their soft tissue is only rarely preserved. Since only a few examples of soft tissue from conodonts have survived, it is very difficult to determine how they grew.
Analyses carried out by FAU researchers are now shedding more light on the subject. By using electron microscopes, the scientists examined the layers of conodont teeth to learn more about how they grew. During this scanning process, a material is bombarded with electrons. Different materials reflect a different number of electrons back to the microscope. For example, heavy elements reflect electrons more strongly than lighter ones, which is why they are shown in a lighter colour on the image. This method enabled researchers to reproduce the individual layers and investigate them at a much higher resolution than before.
By using X-ray spectroscopy, in which elements are detected by means of the the radiation they emit, the scientists were also able to analyse the chemical composition of each layer.
The teeth grew in an alternating cycle between wear and the growth of new layers. Furthermore, the shape of the teeth varied greatly depending on the animals’ stage of growth. Using the chemical composition and the shape of the teeth, the researchers were able to identify three stages of growth during the development of an animal that were influenced (amongst others) by feeding habits. After the first stage, a type of larval state, in which food was not digested mechanically (by chewing), conodonts evolved into the first hunters during the second and third stages of growth. During this time, their teeth underwent a metamorphosis as they evolved into predators.
Up to now, there have been two models to explain how conodont teeth were able to regenerate themselves. In contrast to human teeth, for example, which grow from the inside out, conodonts’ teeth repaired themselves from the outside, continuously adding new layers. One theory developed by scientists is that conodonts retracted their teeth during periods of rest, and the apposition of new layers in epidermal pockets induced growth. This could be compared to the mechanism of retractable teeth used for injecting venom by some species of snake. On the other hand, another theory suggests that the teeth were permanently enveloped by tissue and a type of horn cap, allowing new layers to build up over time. The research carried out by FAU scientists has now confirmed the first theory.
The results of the research have been published under the title “Wear, tear and systematic repair: testing models of growth dynamics in conodonts with high-resolution imaging” in the journal Proceedings of the Royal Society B.
Reference:
Bryan Shirley et al, Wear, tear and systematic repair: testing models of growth dynamics in conodonts with high-resolution imaging, Proceedings of the Royal Society B: Biological Sciences (2018). DOI: 10.1098/rspb.2018.1614
A 127-million-year-old fossil bird, Jinguofortis perplexus (reconstruction on the right, artwork by Chung-Tat Cheung), second earliest member of the short-tailed birds Pygostylia. Credit: WANG Min
A newly identified extinct bird species from a 127 million-year-old fossil deposit in northeastern China provides new information about avian development during the early evolution of flight.
Drs. Wang Min, Thomas Stidham, and Zhou Zhonghe from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences reported their study of the well-preserved complete skeleton and feathers of this early bird in the Proceedings of the National Academy of Sciences (PNAS).
The analysis of this early Cretaceous fossil shows it is from a pivotal point in the evolution of flight—after birds lost their long bony tail, but before they evolved a fan of flight feathers on their shortened tail.
The scientists named this extinct species Jinguofortis perplexus. The genus name “Jinguofortis” honors women scientists around the world. It derives from the Chinese word “jinguo,” meaning female warrior, and the Latin word “fortis” meaning brave.
Jinguofortis perplexus has a unique combination of traits, including a jaw with small teeth like its theropod dinosaur relatives; a short bony tail ending in a compound bone called a pygostyle; gizzard stones showing that it mostly ate plants; and a third finger with only two bones, unlike other early birds.
The fossil’s shoulder joint also gives clues about its flight capacity. In flying birds, the shoulder, which experiences high stress during flight, is a tight joint between unfused bones. In contrast, Jinguofortis perplexus preserves a shoulder girdle where the major bones of the shoulder, the shoulder blade (scapula) and the coracoid, are fused to one another, forming a scapulocoracoid.
The existence of a fused shoulder girdle in this short-tailed fossil suggests evolutionary variety during this stage of evolution, which probably resulted in different styles of flight.Based on its skeleton and feathers, Jinguofortis perplexus probably flew a bit differently than birds do today.
Measurement of the fossil’s wing size and estimation of its body mass show that the extinct species had a wing shape and wing loading (wing area divided by body mass) similar to living
Reference:
Min Wang el al., “A new clade of basal Early Cretaceous pygostylian birds and developmental plasticity of the avian shoulder girdle,” PNAS (2018). www.pnas.org/cgi/doi/10.1073/pnas.1812176115
The Highland Giant: Artist Viktor Radermacher’s reconstuction of what Ledumahadi mafube may have looked like. Another South African dinosaur, Heterodontosaurus tucki, watches in the foreground. Credit: Viktor Radermacher
A new species of a giant dinosaur has been found in South Africa’s Free State Province. The plant-eating dinosaur, named Ledumahadi mafube, weighed 12 tonnes and stood about four metres high at the hips. Ledumahadi mafube was the largest land animal alive on Earth when it lived, nearly 200 million years ago. It was roughly double the size of a large African elephant.
A team of international scientists, led by University of the Witwatersrand (Wits) palaeontologist Professor Jonah Choiniere, described the new species in the journal Current Biology today.
The dinosaur’s name is Sesotho for “a giant thunderclap at dawn” (Sesotho is one of South Africa’s 11 official languages and an indigenous language in the area where the dinosaur was found).
“The name reflects the great size of the animal as well as the fact that its lineage appeared at the origins of sauropod dinosaurs,” said Choiniere. “It honours both the recent and ancient heritage of southern Africa.”
Ledumahadi mafube is one of the closest relatives of sauropod dinosaurs. Sauropods, weighing up to 60 tonnes, include well-known species like Brontosaurus. All sauropods ate plants and stood on four legs, with a posture like modern elephants. Ledumahadi evolved its giant size independently from sauropods, and although it stood on four legs, its forelimbs would have been more crouched. This caused the scientific team to consider Ledumahadi an evolutionary “experiment” with giant body size.
Ledumahadi’s fossil tells a fascinating story not only of its individual life history, but also the geographic history of where it lived, and of the evolutionary history of sauropod dinosaurs.
“The first thing that struck me about this animal is the incredible robustness of the limb bones,” says lead author, Dr Blair McPhee. “It was of similar size to the gigantic sauropod dinosaurs, but whereas the arms and legs of those animals are typically quite slender, Ledumahadi’s are incredibly thick. To me this indicated that the path towards gigantism in sauropodomorphs was far from straightforward, and that the way that these animals solved the usual problems of life, such as eating and moving, was much more dynamic within the group than previously thought.”
The research team developed a new method, using measurements from the “arms” and “legs” to show that Ledumahadi walked on all fours, like the later sauropod dinosaurs, but unlike many other members of its own group alive at its time such as Massospondylus. The team also showed that many earlier relatives of sauropods stood on all fours, that this body posture evolved more than once, and that it appeared earlier than scientists previously thought.
“Many giant dinosaurs walked on four legs but had ancestors that walked on two legs. Scientists want to know about this evolutionary change, but amazingly, no-one came up with a simple method to tell how each dinosaur walked, until now,” says Dr Roger Benson.
By analysing the fossil’s bone tissue through osteohistological analysis, Dr Jennifer Botha-Brink from the South African National Museum in Bloemfontein established the animal’s age.
“We can tell by looking at the fossilised bone microstructure that the animal grew rapidly to adulthood. Closely-spaced, annually deposited growth rings at the periphery show that the growth rate had decreased substantially by the time it died,” says Botha-Brink. This indicates that the animal had reached adulthood.
“It was also interesting to see that the bone tissues display aspects of both basal sauropodomorphs and the more derived sauropods, showing that Ledumahadi represents a transitional stage between these two major groups of dinosaurs.”
Ledumahadi lived in the area around Clarens in South Africa’s Free State Province. This is currently a scenic mountainous area, but looked much different at that time, with a flat, semi-arid landscape and shallow, intermittently dry streambeds.
“We can tell from the properties of the sedimentary rock layers in which the bone fossils are preserved that 200 million years ago most of South Africa looked a lot more like the current region around Musina in the Limpopo Province of South Africa, or South Africa’s central Karoo,” says Dr Emese Bordy.
Ledumahadi is closely related to other gigantic dinosaurs from Argentina that lived at a similar time, which reinforces that the supercontinent of Pangaea was still assembled in the Early Jurassic. “It shows how easily dinosaurs could have walked from Johannesburg to Buenos Aires at that time,” says Choiniere.
South Africa’s Minister of Science and Technology Mmamoloko Kubayi-Ngubane says the discovery of this dinosaur underscores just how important South African palaeontology is to the world.
“Not only does our country hold the Cradle of Humankind, but we also have fossils that help us understand the rise of the gigantic dinosaurs. This is another example of South Africa taking the high road and making scientific breakthroughs of international significance on the basis of its geographic advantage, as it does in astronomy, marine and polar research, indigenous knowledge, and biodiversity,” says Kubayi-Ngubane.
The research team behind Ledumahadi includes South African-based palaeoscientists, Dr Emese Bordy and Dr Jennifer Botha-Brink, from the University of Cape Town and the South African National Museum in Bloemfontein, respectively.
The project also had a strong international component with the collaboration of Professor Roger BJ Benson of Oxford University and Dr Blair McPhee, currently residing in Brazil.
“South Africa employs some of the world’s top palaeontologists and it was a privilege to be able to build a working group with them and leading researchers in the UK,” says Choiniere, who recently emigrated from the USA to South Africa. “Dinosaurs didn’t observe international boundaries and it’s important that our research groups don’t either.”
Reference:
Blair W. McPhee, Roger B.J. Benson, Jennifer Botha-Brink, Emese M. Bordy, Jonah N. Choiniere. A Giant Dinosaur from the Earliest Jurassic of South Africa and the Transition to Quadrupedality in Early Sauropodomorphs. Current Biology, 2018; DOI: 10.1016/j.cub.2018.07.063
It is one of the biggest mud volcanoes of the world with 404 meters height.
It is half cone form and diameter of crater more than 350meters width.
The last eruption of this volcano was 06 February 2017, and 23 September 2018 by time 05:40 it started eruption again. The last eruption we can separate to 3 phases, by 05:40 we have got information from the locals there was a gas explosion and local earthquake.
By 08:52 we noticed dark mud flow towards south-east and south directions. Mudflow was very fast with speed approximately 30 km/h or 8 m/sec!
Thir eruption phase started at 09:47 and we noticed huge fireball lifting from its crater. Gas and mud eruption continued until 13:00.
To the next day, mudflow stopped and length of flow was 3-3.5 km long, approximately height of mud flow is 6 – 7 meters. Approximately erupted materials calculated as 2,5- 3 mln tons of mud.
It was one of the most powerful eruptions this mud volcano on its history, and most powerful eruption for this year.
I`d like to remind there is almost 800 mud volcanoes in the world and almost half of them located in the Azerbaijan Republic.
A combined image of Earth’s plates and their boundaries. Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio
A new study suggests that plate tectonics—a scientific theory that divides the earth into large chunks of crust that move slowly over hot viscous mantle rock—could have been active from the planet’s very beginning. The new findings defy previous beliefs that tectonic plates were developed over the course of billions of years.
The paper, published in Earth and Planetary Science Letters, has important implications in the fields of geochemistry and geophysics. For example, a better understanding of plate tectonics could help predict whether planets beyond our solar system could be hospitable to life.
“Plate tectonics set up the conditions for life,” said Nick Dygert, assistant professor of petrology and geochemistry in UT’s Department of Earth and Planetary Sciences and coauthor of the study. “The more we know about ancient plate tectonics, the better we can understand how Earth got to be the way it is now.”
For the research, Dygert and his team looked into the distribution of two very specific noble gas isotopes: Helium-3 and Neon-22. Noble gases are those that don’t react to any other chemical element.
Previous models have explained the Earth’s current Helium-3/Neon-22 ratio by arguing that a series of large-scale impacts (like the one that produced our moon) resulted in massive magma oceans, which degassed and incrementally increased the ratio of the Earth each time.
However, Dygert believes the scenario is unlikely.
“While there is no conclusive evidence that this didn’t happen,” he said, “it could have only raised the Earth’s Helium-3/Neon-22 ratio under very specific conditions.”
Instead, Dygert and his team believe the Helium-3/Neon-22 ratio raised in a different way.
As the Earth’s crust is continuously formed, the ratio of helium to neon in the mantle beneath the crust increases. By calculating this ratio in the mantle beneath the crust, and considering how this process would affect the bulk Earth over long periods of time, a rough timeline of Earth’s tectonic plate cycling can be established.
“Helium-3 and Neon-22 were produced during the formation of the solar system and not by other means,” Dygert said. “As such, they provide valuable insight into Earth’s earliest conditions and subsequent geologic activity.”
Reference:
Nick Dygert et al, Plate tectonic cycling modulates Earth’s 3 He/ 22 Ne ratio, Earth and Planetary Science Letters (2018). DOI: 10.1016/j.epsl.2018.06.044
In the Panhandle of Texas – here an area near Silverton – one can witness how the High Plains, dotted with lakes, gradually erode at the edges. Source: Google Earth / Landsat / Copernicus
Starting at the eastern foot of the Rocky Mountains in the midwest United States, the dramatic landscape of the High Plains stretches across several US states. Dropping just a few hundred meters over a length of more than 500 kilometres, these plains have only a very gentle gradient and the nearly flat surfaces exhibit unique ecosystems, making them a geological and ecological anomaly.
In the High Plains there are hundreds of thousands of small ephemeral lakes known as playas, that are filled with rainwater only during wet seasons, drying out completely during dry periods. The lakes provide an important breeding, resting and wintering habitat for millions of birds and also supply recharge to the groundwater reservoir known as the Ogallala aquifer. At 450,000 square kilometres, it is the largest aquifer in North America. Without these groundwater resources, agriculture in this dry region would be nearly impossible.
By no means a geological bore
Geologists have given little attention to the High Plains in recent times. “For alpine geologists used to working in high mountains, the region is too flat and considered uninteresting,” says Sean Willett, a professor of geology at ETH Zurich, with a chuckle. It was by chance that he and his two colleagues from the University of Nevada developed an interest in the region when they noticed “peculiar patterns of streams” crossing the High Plains. They have now published their reconstruction of the region’s unusual geological history in “Nature.”
The High Plains were formed 20 million years ago. Earth scientists have recently discovered a zone of unusually hot material in the Earth’s mantle that creates a wave of uplift that is slowly shifting from west to east under the continental plate. This wave first uplifted the Colorado Plateau, then the Rockies and finally the plains themselves. This resulted in a steeper gradient of the mountains towards the plains, accelerating erosion. For 15 million years, a massive flow of sediment poured out of the mountains, down the river valleys and into the plains.
Sediment transported by the rivers was deposited to form huge alluvial fans at the foot of the mountains. Gravel and coarse sand completely filled river valleys and all older topography, effectively repaving the landscape to form the gentle slopes of the modern high plains.
Lakes with limestone sealant
Because alluvial fans only have a very low gradient, rivers flowing down its surface lack erosive power. The surface of these plains sealed with sand, mud and clay, thus making it possible for rain water to remain in sinks to form lakes. Chemical processes eventually led to a calcification of the lakebeds and soils, forming limestone layers up to 10 meters thick. Finally, as it aged, cracks formed in the limestone, allowing water to seep through and feed a groundwater reservoir of vast area and volume, hosted in the gravels shed from the mountains.
The flow of sediment finally stopped around three to five million years ago. Since then, the High Plains’ surfaces have changed very little (with the exception of human impact). “They are a preserved ancient landscape,” says Willett.
Rivers flowing from the Rocky Mountains did, however, seek out new paths and carved deeper into the subsurface along the edges of the prehistoric alluvial fans. This inexorable process is still underway: the rivers continue to erode the alluvial fans, which is evident in the formation of escarpments and badlands with dendritic patterns of streams and rivers cutting into the plateaus of the High Plains. “What we are seeing today is a landscape in transition,” the ETH professor points out. “It will take five or ten million years until the High Plains have completely eroded.”
An unstoppable disintegration of the alluvial fans
Willet does not see any immediate threat to the groundwater supply. However, people should be aware that the forces breaking down the High Plains are responsible for where groundwater is found today and where agriculture is possible.
There is nowhere else in the world quite like the High Plains. There are, of course, gigantic alluvial plains in South America as well, and in the part of the Himalayas located in India. “But the High Plains have been inactive for nearly five million years, whereas the other large alluvial fans are still in the process of formation,” says the researcher.
Reference:
Sean D. Willett, Scott W. McCoy, Helen W. Beeson. Transience of the North American High Plains landscape and its impact on surface water. Nature, 2018; 561 (7724): 528 DOI: 10.1038/s41586-018-0532-1
This image shows widely-felt earthquakes that struck north-central Oklahoma and southern Kansas and the probability that those areas will experience potentially damaging induced earthquakes in 2018 and 2020. Manmade earthquakes in this region are caused by deep injection of wastewater from oil and gas operations. Credit: Cornelius Langenbruch
Earthquakes in Oklahoma and Kansas had been on the rise due to injection of wastewater — a byproduct of oil and gas operations — before regulations started limiting injections. Now a new model developed by Stanford University researchers incorporates earthquake physics and the Earth’s hydrogeologic response to wastewater injection to forecast a decrease in human-made earthquakes in Oklahoma and Kansas through 2020.
The model is based on publicly available data on wastewater injection into the Arbuckle formation, a nearly 7,000-foot-deep sedimentary formation underlying north-central Oklahoma and southern Kansas. Assuming wastewater injection from oil and gas operations continues at its current rate, researchers mapped the likelihood that the region will experience future earthquakes. The research appears Sept. 26 in the journal Nature Communications.
“We’ve created a detailed model that allows regulators to know where most of the problems are likely to occur,” said co-author Mark Zoback, the Benjamin M. Page Professor of Geophysics at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth). “This can be used in Oklahoma, or elsewhere, to provide a scientific basis for regulatory action.”
Local insights
Oil and gas operations often produce large volumes of salty water that they dispose of by injecting it deep underground to protect water in aquifers near the surface used for drinking, livestock and irrigation.
Fluid injected into the Arbuckle formation increases pressure that spreads over a large area. This pressure is problematic because it can affect large faults nearby that are already under stress from tectonic processes. These faults are capable of producing widely felt and potentially damaging earthquakes, if reached by the pressure increase caused by injection.
The same pressure increase in different areas can cause up to 100 times the number of earthquakes, according to lead author Cornelius Langenbruch, a postdoctoral researcher at Stanford Earth. The earthquakes are not necessarily concentrated in areas where the pressure change is highest. In order to understand where earthquakes will or will not occur on a local scale, the new model evaluates the pressure increase in the context of the area’s vulnerable, pre-existing faults.
“It was surprising for me to see that the local susceptibility to earthquakes fluctuates by such a large amount,” Langenbruch said. “The example of Oklahoma shows that the key to managing seismic hazards related to these human-made, induced earthquakes is managing how much and where the wastewater is injected.”
Mandated reduction
Oklahoma’s induced earthquakes increased drastically around 2009 and peaked in 2015, with nearly 1,000 widely felt earthquakes spread across the northern and central parts of the state. Oklahoma’s public utilities commission, the Oklahoma Corporation Commission, mandated a 40 percent water injection reduction in early 2016 and the number of earthquakes declined thereafter.
The new model — which includes data from 809 injection wells from 2000 through 2018 — shows there will be a 32 percent, 24 percent and 19 percent probability of potentially damaging earthquakes of magnitude 5.0 or above in 2018, 2019 and 2020, respectively, suggesting that Oklahoma’s policies are working. If current injection practices in north-central Oklahoma and southern Kansas continue, one potentially damaging magnitude 5.0 or larger earthquake is expected to occur through 2020.
“The result of the new study is definitely good news — it shows injection rate reductions are still effective. In 2015 and 2016 the probabilities were as high as 70 percent,” Langenbruch said. “However, the problem is that earthquake probabilities in some areas are still much higher than historic rates.”
Future scenarios
The predictive maps from the study allow residents of Oklahoma and Kansas to see the probability that potentially damaging earthquakes will strike close to their homes. The new model can also be used to evaluate future injection scenarios intended to mitigate seismic hazards.
“The nice thing about the methodology is not only the predictions it makes, but its ability to make new predictions based on new measures that might be taken by the regulators,” Zoback said. “It turns out you can do these analyses fairly early in the process.”
The researchers hope this model will also be used in other areas with expanding oil and gas operations. Places like the Permian Basin in West Texas are being developed at an incredible rate and water injection is probably resulting in earthquakes in that area already, Zoback said.
A co-author of the paper is Matthew Weingarten, an assistant professor at San Diego State University who conducted research for the study as a postdoctoral researcher at Stanford. Zoback is also a senior fellow at Stanford’s Precourt Institute for Energy, an affiliate of the Stanford Woods Institute for the Environment and the director of the Stanford Natural Gas Initiative. Funding for the study was provided by the Stanford Center for Induced and Triggered Seismicity (SCITS), an industrial affiliates program involving 10 Stanford professors.
Reference:
Cornelius Langenbruch, Matthew Weingarten, Mark D. Zoback. Physics-based forecasting of man-made earthquake hazards in Oklahoma and Kansas. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-018-06167-4
This is an illustration of the research finds by Sae Bom Ra, an Adelphi University scientific illustration major. Credit: Sae Bom Ra/Adelphi University
A newly discovered fossil suggests that large, flowering trees grew in North America by the Turonian age, showing that these large trees were part of the forest canopies there nearly 15 million years earlier than previously thought. Researchers from Adelphi University and the Burpee Museum of Natural History found the fossil in the Mancos Shale Formation in Utah, in ancient delta deposits formed during a poorly understood interval in the North American fossil record.
“These discoveries add much more detail to our picture of the landscape during the Turonian period than we had previously,” says Michael D’Emic, assistant professor of biology at Adelphi, who organized the study. “Since Darwin, the evolution of flowering plants has been a topic of debate for paleontologists because of their cryptic fossil record. Our paper shows that even today it is possible for a single fossil specimen to change a lot about what we know about the early evolution of the group.
“Understanding the past is the key to managing the future,” D’Emic added. “Learning how environments evolved and changed in the past teaches us how to better prepare for future environmental change.”
Aside from the large petrified log, the team reports fossilized foliage from ferns, conifers and angiosperms, which confirm that there was forest or woodland vegetation 90 million years ago in the area, covering a large delta extending into the sea. The team also reports the first turtle and crocodile remains from this geologic layer, as well as part of the pelvis of a duck-billed dinosaur; previously, the only known vertebrate remains found were shark teeth, two short dinosaur trackways, and a fragmentary pterosaur.
“Until now most of what we knew about plants from the Ferron Sandstone came from fossil pollen and spores,” says Nathan Jud, co-author and assistant professor of biology at William Jewell College. “The discovery of fossil wood and leaves allows us to develop a more complete picture of the flora.”
Reference:
Nathan A. Jud, Michael D. D’emic, Scott A. Williams, Josh C. Mathews, Katie M. Tremaine, and Janok Bhattacharya. A new fossil assemblage shows that large angiosperm trees grew in North America by the Turonian (Late Cretaceous). Science Advances, 2018 DOI: 10.1126/sciadv.aar8568
Note: The above post is reprinted from materials provided by Adelphi University.
Careful analysis of data collected after the 3 September 2017 North Korean declared nuclear test explosion has allowed seismologists to distinguish the separate seismic signatures of the explosion, a collapse of the explosion cavity and even several small earthquakes that occurred after the collapse.
The data, compared with those collected from 20th-century Nevada nuclear test sites, can help refine seismologists’ methods of identifying nuclear test explosions around the world, write William R. Walter and his colleagues at Lawrence Livermore National Laboratory. Their paper is published as part of a special focus section on the September 2017 North Korean explosion and its aftermath in the journal Seismological Research Letters.
The September 2017 body-wave magnitude 6.1 underground test by the Democratic People’s Republic of Korea (DPRK) is the largest such test in more than 20 years, and is the sixth declared nuclear test by the DPRK since 2006. The September explosion is an order of magnitude larger than the next largest test by the country, which occurred in September 2016.
The researchers used a method that compares the ratio between regional P- and S-wave amplitudes to distinguish the seismic signature of an explosion compared to an earthquake, at distances about 200 to 1500 kilometers away from the seismic wave source. (P-waves compress rock in the same direction as the seismic wave’s movement, while S-waves move rock perpendicular to the direction of the wave.) “In the P/S ratio discriminant we use to identify explosions, it is the lack of S-waves at high frequency that is distinctive of the explosions,” Walter explained.
Walter and colleagues showed that the ratio could separate the six North Korean declared nuclear tests from natural earthquakes in the region, and that the same method could be used to successfully distinguish between historic Nevada Test Site nuclear explosions and earthquakes in the western United States.
However, there was another unusual seismic event, occurring about eight and half minutes after the explosion, which also drew the attention of the seismologists. Models of seismic waveforms of the event led the scientists to conclude that the event may have been the ground collapsing around an underground cavity left by the explosion.
Although collapses similar to this were sometimes seen after Nevada Test Site explosions, “this is the first time, to my knowledge, that we have remotely observed seismic waves from a collapse with modern instrumentation at a foreign test site,” said Walter. “It is important to be able to determine this collapse was not another nuclear test.”
Several features of the post-explosion event’s waveforms mark it as a collapse rather than an explosion, the researchers say, including the relative lack of high frequency energy compared to explosion waveforms.
“Identifying the event as a collapse is another indicator the 3 September 2017 event was a nuclear test that generated a large vaporization cavity that collapsed eight and half minutes later,” said Walter. “But we want to continue to develop methods to identify collapses to distinguish them from both explosions and earthquakes.”
Researchers studying the September 2017 nuclear test data also noted two smaller seismic events occurring after the explosion, of magnitudes 2.6 and 3.4, that appear from the P- to S-wave ratios to be small earthquakes located four to eight kilometers north of the explosion site.
“We had not remotely observed any aftershocks from the prior DPRK declared nuclear tests, so the earthquakes following the explosion got people’s attention,” Walter said. “Again, we wanted to determine they were not additional smaller nuclear tests. Alternatively, we wanted to determine they were not associated with the collapse event.” Upon careful re-analysis of the continuous data the researchers found a number of additional small earthquakes, including some that occurred before the 3 September 2017 declared nuclear test.
Given the timing these earthquakes do not appear to be true “aftershocks” of the nuclear test, Walter and colleagues concluded, though they may be related and possibly induced by the explosion. “The fact that apparent tectonic earthquakes are occurring near the DPRK test site reveals information about the state of [seismic] stress in the region, which may help us better understand the explosion seismic signatures,” said Walter.
Reference:
Andrea Chiang et al, Moment Tensor Source‐Type Analysis for the Democratic People’s Republic of Korea–Declared Nuclear Explosions (2006–2017) and 3 September 2017 Collapse Event, Seismological Research Letters (2018). DOI: 10.1785/0220180130
