Fluid-assisted interaction of peraluminous metapelites with trondhjemitic magma within the Petronella shear-zone, Limpopo Complex, South Africa
Authors:
Safonov et al
Abstract:
The principal problem concerning the evolution of Precambrian granulite complexes located between granite-greenstone cratons is their interaction with the underthrusted greenstone belts during exhumation from the lower crust. Besides evidence for pervasive and localized fluid fluxes arising from devolatilization of the greenschist and amphibolite-facies rocks in the course of their burial underneath the granulites, this interaction might also be expressed in formation of diverse magmas of granitic, trondhjemitic and granodioritic composition. We present results of a petrological, fluid inclusion and thermobarometric study of interaction between fluidized trondhjemitic magma and peraluminous metapelitic granulites associated with the regional high-grade Petronella shear zone located in the Southern Marginal Zone (SMZ) of the Limpopo Granulite Complex (South Africa). The hot (T ∼ 1000 °C) trondhjemitic magma, which, presumably, originated from partial melting of a basaltic (amphibolite) material at the base of the granulite complex or at the top of the underthrusted greenstone blocks, intruded granulites at P ∼ 8.0–9.5 kbar (24–28 km depth) at 2.667 ± 0.9 Ga during the exhumation of the SMZ. The magma heated and assimilated orthopyroxene-cordierite metapelites and dragged them to a depth of 18–20 km (6.3–6.5 kbar). The magma was heterogeneously saturated with MgO, FeO, Al2O3 by the dissolved metapelites. This process provoked crystallization of several garnet generations from the trondhjemitic melt. Various mineral assemblages included in the different generations of garnet allowed application of TWQ method combined with PERPLE_X pseudo sections to trace sub-isobaric cooling of the magma from T ∼ 900–600 °C at 5.5–6.5 kbar. The isobaric cooling also affected the associated metapelites. Fluid inclusions trapped in garnet and quartz in the trondhjemite show that the magma transported carbonic fluid with densities corresponding to the late stages of magma cooling (600–650 °C and 5.5–6.5 kbar). Carbonic fluids coexisted with aqueous-salt fluids (preserved as inclusions with salinity up to 20.58 wt.% NaCl eq.). These low water activity fluids (aH2O less than 0.3)(aH2O less than 0.3) bearing Na, K and Ca salts, being exsolved from the magma on cooling and solidification, provoked formation of complex Na-gedrite + biotite + sillimanite + quartz ± staurolite ± plagioclase-bearing assemblages after cordierite in metapelites at temperatures 630–570 °C and pressures 5.5–6.5 kbar. These data provide evidence that hot trondhjemitic melts played a critical role in the exhumation of granulites onto the adjacent granite-greenstone craton. The trondhjemite transferred heat from the lower to the middle crust and transported large volumes of external aqueous-carbonic-salt fluids that participated in the rehydration of a significant portion of the SMZ.
Tuesday, October 07, 2014
Evidence of NeoArchean Magma Transporting Large Amounts of Water and Carbon dioxide in South Africa
Greenland Ice Sheet Meltwater Channels More Complex Than Thought
An international research team's field work, drilling and measuring melt rates and ice sheet movement in Greenland is showing that things are, in fact, more complicated than we thought.
"Although the Greenland Ice Sheet initially speeds up each summer in its slow-motion race to the sea, the network of meltwater channels beneath the sheet is not necessarily forming the slushy racetrack that had been previously considered," said Matthew Hoffman, a Los Alamos National Laboratory scientist on the project.
A high-profile paper appearing in Nature this week notes that observations of moulins (vertical conduits connecting water on top of the glacier down to the bed of the ice sheet) and boreholes in Greenland show that subglacial channels ameliorate the speedup caused by water delivery to the base of the ice sheet in the short term. By mid summer, however, the channels stabilize and are unable to grow any larger. In a previous paper appearing in Science, researchers had posited that the undersheet channels were not even a consideration in Greenland, but as happens in the science world, more data fills in the complex mosaic of facts and clarifies the evolution of the meltwater flow rates over the seasons.
In reality, these two papers are not inconsistent - they are studying different places at different times - and they both are consistent in that channelization is less important than previously assumed, said Hoffman.
link.
Monday, October 06, 2014
26,000 Bitcoins Dumped Over Weekend, Dropping Price
After buyers snapped up $7.8m worth of bitcoins that were selling for $300 each on exchange Bitstamp on Monday, bitcoin’s price appears to have found a hard floor in what has been a largely unpredictable trading period recently.
On Sunday, bitcoin’s price dropped through the 18-month average purchase price of $337.60, signalling uncertainty to many traders in the market. Then, in the early hours of the Asian morning on Monday, a sell order of 26,000 BTC at $300 that was placed on exchange Bitstamp brought a temporary halt to the volatile price and narrowed bid-ask spreads between the four exchanges in CoinDesk’s Bitcoin Price Index (BPI).
By the time of the European morning however, buyers had snapped up the entire order and the BPI jumped up into the low-to-mid-$320s.
“When the sell order for 26,000 BTC came onto Bitstamp, the price dropped from $317 to $300 in two seconds. I’ve just bought back in now that block has been lifted,” said Adam O’Brien, CEO of BTC Solutions, a Canada-based provider of ATM exchanges and leveraged trading services for bitcoin.
link.
One interpretation is the investor is purposefully trying to force down the price of BTC so they can buy back at a much lower price. Call it something of a confidence scam. The other possibility is someone has been holding for a long time and has lost confidence in BTC going to reclaim the $1k+ mark. Alternately, it was an early adopter who found they needed the $.
DOOM! DOOM! DOOM! One in Three Jobs to be Lost to Robopocalypse by 2025
Gartner sees things like robots and drones replacing a third of all workers by 2025, and whether you want to believe it or not, is entirely your business.
This is Gartner being provocative, as it is typically is, at the start of its major U.S. conference, the Symposium/ITxpo.
Take drones, for instance.
"One day, a drone may be your eyes and ears," said Peter Sondergaard, Gartner's research director. In five years, drones will be a standard part of operations in many industries, used in agriculture, geographical surveys and oil and gas pipeline inspections.
"Drones are just one of many kinds of emerging technologies that extend well beyond the traditional information technology world -- these are smart machines," said Sondergaard.
Smart machines are an emerging "super class" of technologies that perform a wide variety of work, both the physical and the intellectual kind, said Sondergaard. Machines, for instance, have been grading multiple choice for years, but now they are grading essays and unstructured text.
This cognitive capability in software will extend to other areas, including financial analysis, medical diagnostics and data analytic jobs of all sorts, says Gartner.
"Knowledge work will be automated," said Sondergaard, as will physical jobs with the arrival of smart robots.
"Gartner predicts one in three jobs will be converted to software, robots and smart machines by 2025," said Sondergaard. "New digital businesses require less labor; machines will be make sense of data faster than humans can."
link.
Silicon Valley Startup Aims to Make Trucks into Hybrids
Ian Wright designed what may be one of the coolest street-legal cars of all time: the electric X1 looked like a Formula 1 racecar and went from zero to 60 in a breathtaking 2.9 seconds. Now, though, all Wright wants to talk about is trucks, especially the workaday delivery trucks and garbage trucks that ply city streets.
Why the excitement? Wright is the founder of Wrightspeed, a San Jose, CA-based startup that’s designed electric powertrains for medium- and heavy-duty trucks. “Garbage trucks are the perfect driving cycle for us: they get two or three miles per gallon, drive 130 miles a day with 1,000 hard stops that chew on the brakes. They’re just perfect,” he says.
Wright was among the founders of Tesla Motors. But despite his background in working on luxury performance cars, he’s come around to thinking that the biggest opportunity for electric vehicle disruption is where most of the fuel is burned—that is, big trucks. Cars may go through a few hundred gallons of gas a year but a commercial truck will burn through thousands of gallons or more. That means there’s a better financial incentive in terms of fuel savings to go electric.
link.
US Navy Looking to Swarming Unmanned Surface Ships for Protecting Ports
Navy ships are at their most vulnerable when they’re resupplying in port or navigating narrow straits or rivers because they’re tricky to maneuver in tight quarters and vulnerable to attack. The attack 14 years ago on the USS Cole as it refueled while berthed in Yemen, an attack that killed 17 American sailors and reiterated the need to protect warships in port.
To counter asymmetric attacks—the 505-foot Cole was attacked by a small craft packed with explosives that ripped 40-foot gash in the destroyer—the Navy uses small patrol craft for close-quarters defense. And that means placing sailors in the line of fire. That got the Office of Naval Research into developing autonomous technology for small “swarmboats” that could be used for risky jobs.
These vessels would, much like the autonomous minesweepers the Army is testing, act as a force multiplier, allowing one sailor to do the work of several, from a safe location.
The technology, called Control Architecture for Robotic Agent Command and Sensing (CARACaS), is essentially an autopilot on steroids that can be installed on nearly any boat. During a test in August on the James River in Newport News, Virginia, Navy researchers used 13 rigid-hulled inflatable boats equipped with the technology to escort a “high-value” ship and swarm an “enemy” vessel. The boats decide on their own where to go, when to steer, and when to apply the throttle. A human operator, who can be in another ship, a helicopter, or well away from the action, uses a laptop to tell the swarmboats which craft are to be protected and which are to be attacked. Think of it as an officer giving his (robotic) sailors a mission—protect this guy, attack that one—and letting them determine how best to fulfill it.
link.
Also note DARPA's unmanned ASW ship which has started construction.
Sahara may Date Back to Miocene Neogene
The desertification of northern Africa may have started 7 million years ago, or more than twice as long ago as earlier estimates of the Sahara's age, climate simulations suggest. The findings also hint that this shift in climate would have been triggered by the gradual shrinking of the Tethys Sea, the predecessor of today’s Mediterranean.
The sands of the Sahara may seem timeless, but most geological data suggests that the world's largest non-polar desert formed between 2 million and 3 million years ago, about the same time as cycles of ice ages began plaguing the Northern Hemisphere.
Still, scientists have unearthed tantalizing clues that the Sahara may be much older than 3 million years old, says Zhongshi Zhang, a palaeoclimatologist at the Bjerknes Center for Climate Research in Bergen, Norway and a a co-author of the latest study, published on September 17 in Nature. Almost a decade ago, he notes, one team reported evidence of widespread dune deposits estimated to be 7 million years old in northern Chad.
Other analyses, including of long-term variations in the amounts of dust and pollen in sediments drilled from seafloors off northern Africa, chronicle extended dry spells in the region starting about 8 million years ago.
But it has been unclear what might have triggered the aridification, says Zhang. There were no major episodes of mountain formation that might have influenced climate in the region, he notes. Nor do his team's climate simulations suggest that long-term changes in Earth’s orbit or atmospheric concentrations of carbon dioxide are to blame.
link.
Evidence of 125 to 220 Million Year Old Equitorial Martian Mountain Glaciers on Pavonis and Arsia Mons
Preservation of Ancient Ice at Pavonis and Arsia Mons: Tropical Mountain Glacier Deposits on Mars
Authors:
Head et al
Abstract:
Large tropical mountain glacier (TMG) deposits on the northwest flanks of the Tharsis Montes and Olympus Mons volcanoes are interpreted to be the record of ancient climates characteristic of Mars several hundred million years ago when planetary spin-axis obliquity was ~45°. During this era, polar volatiles (predominantly H2O) were mobilized and transferred equatorward, undergoing adiabatic cooling on the Tharsis volcano flanks, and precipitating snow and ice to form cold-based tropical mountain glaciers up to several kilometers in thickness. Subsequent climate change resulted in retreat, sublimation and collapse of the tropical mountain glaciers, leaving the three typical facies observed today: 1) Concentric ridges, the ridged facies, interpreted as drop moraines; 2) knobby facies, interpreted as debris-dominated sublimation residue; and 3) the smooth facies, interpreted as remnant alpine glacial deposits. Ring-mold craters (RMCs) are distinctive features formed by impacts into debris-covered ice. We describe a set of relatively fresh ring-mold craters superposed on the Arsia and Pavonis Mons TMG deposits; we interpret these to indicate that the impact events penetrated a veneer of sublimation lag and excavated buried remnant glacial ice, despite the lack of detection of buried ice by orbital radar instruments. The diameter distribution of the RMCs suggest that the remnant ice lies at a depth of at least 16 m. The TMG deposit ages suggest that these ice deposits date from a period in the range of 125–220 million years before the present; the remnant ice may thus preserve records of the ancient atmospheric gas content and microbiota, as is common in terrestrial glacial ice. Preservation of this ice and the lack of any associated fluvial features suggest that the post-glacial climate has been cold, and related surface temperatures have not been sufficient to bring the buried deposits to the melting point of water.
Jumping Genes Want to be Free: Genomic "Arms Race" Greatly Shaped Human Evolution
New findings by scientists at the University of California, Santa Cruz, suggest that an evolutionary arms race between rival elements within the genomes of primates drove the evolution of complex regulatory networks that orchestrate the activity of genes in every cell of our bodies.
The arms race is between mobile DNA sequences known as "retrotransposons" (a.k.a. "jumping genes") and the genes that have evolved to control them. The UC Santa Cruz researchers have, for the first time, identified genes in humans that make repressor proteins to shut down specific jumping genes. The researchers also traced the rapid evolution of the repressor genes in the primate lineage.
Their findings, published September 28 in Nature, show that over evolutionary time, primate genomes have undergone repeated episodes in which mutations in jumping genes allowed them to escape repression, which drove the evolution of new repressor genes, and so on. Furthermore, their findings suggest that repressor genes that originally evolved to shut down jumping genes have since come to play other regulatory roles in the genome.
"We have basically the same 20,000 protein-coding genes as a frog, yet our genome is much more complicated, with more layers of gene regulation. This study helps explain how that came about," said Sofie Salama, a research associate at the UC Santa Cruz Genomics Institute who led the study.
Retrotransposons are thought to be remnants of ancient viruses that infected early animals and inserted their genes into the genome long before humans evolved. Now they can only replicate themselves within the genome. Depending on where a new copy gets inserted into the genome, a jumping event can disrupt normal genes and cause disease. Often the effect is neutral, simply adding to the overall size of the genome. Very rarely the effect might be advantageous, because the added DNA can itself be a source of new regulatory elements that enhance gene expression. But the high probability of deleterious effects means natural selection favors the evolution of mechanisms to prevent jumping events.
Scientists estimate that jumping genes or "transposable elements" account for at least 50 percent of the human genome, and retrotransposons are by far the most common type.
"There have been successive waves of retrotransposon activity in primate evolution, when a transposable element changed to become expressed and replicated itself throughout the genome until something turned it off," Salama said. "We've discovered a major mechanism by which the genome is able to shut down these mobile DNA elements."
The repressors identified in the new study belong to a large family of proteins known as "KRAB zinc finger proteins." These are DNA-binding proteins that repress gene activity, and they constitute the largest family of gene-regulating proteins in mammals. The human genome has over 400 genes for KRAB zinc finger proteins, and about 170 of them have emerged since primates diverged from other mammals.
According to Salama, her team's findings support the idea that expansion of this family of repressor genes occurred in response to waves of retrotransposon activity. Because repression of a jumping gene also affects genes located near it on the chromosome, the researchers suspect that these repressors have been co-opted for other gene-regulatory functions, and that those other functions have persisted and evolved long after the jumping genes the repressors originally turned off have degraded due to the accumulation of random mutations.
"The way this type of repressor works, part of it binds to a specific DNA sequence and part of it binds other proteins to recruit a whole complex of proteins that creates a repressive landscape in the genome. This affects other nearby genes, so now you have a potential new layer of regulation available for further evolution," Salama said.
link.
A Sebecid Crocodyliform From Miocene Neogene Cuba?
Enigmatic crocodyliforms from the early Miocene of Cuba
Authors:
Brochu et al
Abstract:
Early Miocene deposits from the Domo de Zaza locality, in the south-central Cuban province of Sancti Spiritus, preserve crocodyliform remains, including compressed serrated teeth closely resembling those of South American sebecids. Fragmentary cranial and mandibular material is more difficult to assess. Referral to any other post-Paleogene crocodyliform known from the Western Hemisphere can be ruled out, and phylogenetic analyses are unable to pinpoint its relationships. Similarities can be found with planocraniids, including ventrally oriented and mediolaterally expanded orbital surfaces, but the morphology of the quadrate is inconsistent with a planocraniid affinity. A sebecid in the Miocene of Cuba would be congruent with evidence from other vertebrates suggesting extensive dispersal between the Greater Antilles and South America during the Neogene, and it would be the first Neogene record of the group outside South America. The other crocodyliform may indicate the presence of an endemic West Indian lineage not closely related to any contemporaneous group. It is also consistent with extant Crocodylus arriving in the Neotropics within the past 5–10 million years.
Evidence of Warming and Cooling Events From the Pennsylvanian Carboniferous to the Permian
Warm water benthic foraminifera document the Pennsylvanian–Permian warming and cooling events — The record from the Western Pangea tropical shelves
Author:
Davydov
Abstract:
Shallow warm water benthic foraminifera (SWWBF), including all larger fusulinids (symbiont-bearing benthic foraminifera), are among the best indicators of paleoclimate and paleogeography in the Carboniferous and Permian. The distribution of benthic foraminifera in space and time constrain important tectonic, paleogeographic and climatic events at a global scale. The North American shelves during Pennsylvanian and Permian time – though geographically within the tropical belt – are characterized by temperate environments with significantly lower foraminifera diversification and rare occurrences of warm water Tethyan forms, that are in general appear in the region as a migration entities. Such environments allow documentation of warming episodes associated with sudden immigration of warm water and exotic forms of SWWBF that evolved elsewhere into the area. First occurrence datum (FOD) of the forms exotic to North America during warming episodes are always delayed in respect of their First Appearance Datum (FAD) elsewhere. The time of delay and taxonomic diversity of fusulinids in North America shelves depended on the scale and intensity of the warming episodes. Cooling events, on the other hand, are associated with decreased taxonomic diversity and appearances of endemic forms characteristic only of temperate water provinces. The occurrence of these forms in Boreal and North American provinces appears to be isochronous, as their environments are uniform and induce their uniform and isochronous distribution. Several warming and cooling episodes during Pennsylvanian–Permian time are recognized. The differences between taxonomic variations in each event could potentially be used for provisional estimation of the degree of climatic change. A strong link between biotic and climatic events in North American province and the similarity of biotic changes in the North American and other provinces suggests that paleoclimatic events in North American province were controlled by global factors.
Thermally Extreme Orogeny & Evolution of the Australian Musgrave Region From the Statherian PaleoProterozoic to the Ectasian MesoProterozoic
The burning heart - the Proterozoic geology and geological evolution of the west Musgrave Region, central Australia
Authors:
Howard et al
Abstract:
he Musgrave Province is one of the most geodynamically significant of Australia’s Proterozoic orogenic belts, lying at the intersection of the continent’s three cratonic elements – the West, North and South Australian Cratons. While remoteness and cultural sensitivity have slowed geological research into this region, recent collaborative programs in Western Australia (the west Musgrave Province) have done much to address this. This Focus Review provides a synthesis of this, and previous, work investigating the Mesoproterozoic to Neoproterozoic geological evolution of the province. The Musgrave Province is a Mesoproterozoic to Neoproterozoic belt dominated by granites formed and deformed during several major events. A cryptic juvenile basement is exposed mainly in the east Musgrave Province as c. 1600 – 1550 Ma orthogneiss and in the west Musgrave Province as isolated outcrops of granulite-facies metagranites of the c. 1575 Ma Warlawurru Supersuite. Zircon Hf-isotopic data suggest an earlier major juvenile crust-forming event at c. 1950–1900 Ma. There is, however, no evidence that the province evolved over Archean crust. The c. 1600 – 1550 Ma period probably involved evolution within a primitive arc setting, perhaps developed on c. 1950–1900 Ma oceanic or oceanic-arc crust. Voluminous calc-alkaline plutonism was accompanied by clastic and volcaniclastic basin formation during the 1345–1293 Ma Mount West Orogeny. This stage traced the evolution of a continental arc reflecting the final amalgamation of the combined North and West Australian Craton with the South Australian Craton. The intervening c. 1400 Ma primitive crust - the Madura Province – on which the proto-Musgrave Province had evolved, was consumed during amalgamation. The thickened crust resulting from this accretion was drastically thinned at the beginning of the c. 1220–1150 Ma Musgrave Orogeny as this central part of the new combined craton entered an extraordinary period of high heat flow characterised by c. 100 m.y. of ultrahigh-temperature metamorphism and high-temperature, anhydrous, alkali-calcic magmatism sourced from MASH chambers developed at the base of the thinned crust. The ridged cratonic architecture and a massive accumulation of high radiogenic heat producing granites within the mid crust perpetuated a thin crustal regime. Voluminous magmatism was again triggered during the c. 1090–1040 Ma Giles Event with the evolution of the magmatism-dominated, Ngaanyatjarra Rift. This event was likely initiated through renewed movement along translithospheric faults that intersected the thermally perturbed Musgrave Province, pinned at a cratonic junction. Mantle-derived bimodal magmatism extended more or less continuously for 50 m.y., producing one of the world’s largest layered mafic intrusions and supervolcano-sized additions of juvenile felsic crust, in the form of alkali-calcic to alkali, A-type, rhyolite deposits. Together, the Albany – Fraser Orogen, which developed over the southern margin of the West Australian Craton, and the Musgrave Province mark the preserved edge of the North and West Australian Craton. These two belts show remarkable chronological links between c. 1345 and 1150 Ma but contrasting histories before and after that period. Their period of shared evolution reflects collision and accretion of the South Australian Craton, but their tectonic setting and basement geology throughout that event were very different.
Should North America Integrate More?
NEVER have Latin American leaders talked so much about regional integration as in the past decade. They have cooked up an alphabet soup of organisations, whose chefs hold non-stop summits even as trade among them grows only slowly. But three countries in the Americas have practised integration while eschewing much of the fanfare.
Under the North American Free-Trade Agreement (NAFTA), which came into effect in January 1994, the economies of Mexico and Canada have become ever more closely entwined with that of the United States. Trade between the three has more than tripled, to $1.1 trillion in 2013, and cross-border investment has risen fourfold. Many companies now operate on a North American basis.
Yet this economic entanglement has no match in politics and policy. The Security and Prosperity Partnership of North America, set up by George W. Bush in 2005 to deepen NAFTA, was quietly downgraded four years later to a regular meeting of the three countries’ leaders. An accompanying private-sector “competitiveness council” was disbanded.
Because NAFTA is falsely blamed in the United States for a net loss of manufacturing jobs, it is a subject that Barack Obama prefers not to mention. Stephen Harper, Canada’s Conservative prime minister, hews to his country’s close bilateral relationship with the United States. Mexico’s problems with organised crime, its reputation as a source of migrants (though few now cross the border) and the fear that it might provide an access route for terrorists (though it hasn’t) make closer trilateral ties politically toxic in the other two countries.
This neglect is a missed opportunity, according to a new report* by the Council on Foreign Relations, a New York think-tank. Drawn up by a group led by Robert Zoellick, a Republican former cabinet member, and General David Petraeus, a former commander of American forces in Iraq and Afghanistan, the report makes a passionate case for North America to switch from “an afterthought” to “a central priority for US policy”.
link.
Friday, October 03, 2014
Gulden Draak Knoll Microcontinent Found Off Western Australia
Discovery of a microcontinent (Gulden Draak Knoll) offshore Western Australia: Implications for East Gondwana reconstructions
Authors:
Gardner et al
Abstract:
Analysis of dredged samples from Gulden Draak Knoll demonstrate it is a submarine rifted continental fragment that lies at the boundary between the western Perth Abyssal Plain and Wharton Basin, Indian Ocean. The Knoll comprises a granulite facies basement, including pelitic paragneiss and mafic orthogneiss, with a Cambrian granite inferred to intrude the other rocks. Boulders and cobbles of felsic gneiss with Mesoproterozoic and Cambrian protolith ages were also sampled likely reflecting a complex basement to variable sedimentary and volcanic rocks. The U-Pb isotopic system in Archean and Mesoproterozoic zircon is significantly disturbed, reflecting Cambrian orogenesis that affected all samples. The protolith to garnet-sillimanite-biotite paragneiss has a maximum deposition age of 1163 ± 24 Ma and includes older detrital zircon grains with populations at c. 2.65 Ga and between 1.4-1.1 Ga. A younger population in this sample is interpreted as a mix of newly grown metamorphic zircon and isotopically reset zircon, implying the granulite facies metamorphism occurred at c. 511 ± 5 Ma. Protracted Cambrian orogenesis is indicated by a metamorphic age in the mafic orthogneiss of 530 ± 6 Ma and isotopic disturbance shortly following emplacement of granite (c. 540 Ma with zircon ages disturbed to 509 ± 7 Ma) and the protolith to the felsic orthogneiss (c. 528 Ma with zircon ages disturbed to 510 ± 3 Ma). Xenocrystic zircon grains in Cambrian rocks include Archean (c. 2839 ± 9 Ma) and Mesoproterozoic (1230–1370 Ma) populations also isotopically disturbed during Cambrian orogenesis. Igneous Cambrian zircon grains have less radiogenic Hf-isotope compositions (Hfi = 0.281821-0.281367) than Mesoproterozoic xenocrysts (Hfi = 0.282267-0.281993), indicating limited involvement of the Mesoproterozoic crust in granite production. A more likely source includes Archean crust represented by xenocrysts with Hfi = 0.281399-0.280863. The Gulden Draak Knoll is reconstructed in Gondwana (‘Leeuwin’ full-fit model) along strike of a major structure termed the Indo- Australo- Antarctic Suture (IAAS), recently mapped from geophysical interpretations in Wilkes Land, Antarctica. New isotopic data suggest basement rocks from the Gulden Draak Knoll have affinity to crust exposed either side of the IAAS. Determining if this structure is a suture zone sensu stricto remains to be tested.
Explosive Silicic Volcanism on the Moon
Evidence for explosive silicic volcanism on the Moon from the extended distribution of thorium near the Compton-Belkovich Volcanic Complex
Authors:
Wilson et al
Abstract:
We reconstruct the abundance of thorium near the Compton-Belkovich Volcanic Complex on the Moon, using data from the Lunar Prospector Gamma Ray Spectrometer. We enhance the resolution via a pixon image reconstruction technique, and find that the thorium is distributed over a larger (40 km × 75 km) area than the (25 km × 35 km) high albedo region normally associated with Compton-Belkovich. Our reconstructions show that inside this region, the thorium concentration is 15 - 33 ppm. We also find additional thorium, spread up to 300 km eastward of the complex at ∼2 ppm. The thorium must have been deposited during the formation of the volcanic complex, because subsequent lateral transport mechanisms, such as small impacts, are unable to move sufficient material. The morphology of the feature is consistent with pyroclastic dispersal and we conclude that the present distribution of thorium was likely created by the explosive eruption of silicic magma.
Fertility & Agiculture in PreColumbian Western Argentina
Agricultural suitability and fertility in occidental piedmont of CalchaquÃes Summits (Tucumán, Argentina)
Authors:
Vattuone et al
Abstract:
Our study area is located in the piedmont of CalchaquÃes Summits (Tucumán Province, Northwest Argentina). The objectives of this paper are to improve the knowledge of Pre-Hispanic agricultural practices on landscape and soils, and to provide new knowledge about land fertility of agricultural areas, taking into account the environmental settings. Physical and chemical features, such as structure, texture, pH, calcium, organic and inorganic phosphorus, and available copper, manganese, and iron were taken into account. After photointerpretation and field surveys, two agricultural terraced geomorphological units were sampled. Samples were made in comparable off-site locations and the archaeological sites. After Principal Component Analysis, physicochemical analysis showed that texture is the most significant difference between the two archaeological sites. Agricultural practices introduced high chemical variations, despite the substantial differences between agricultural and off-site profiles. This is the first approach of this nature in Northwest Argentina.
The Maastrichtian Cretaceous Mosasaurs of Morocco
Mosasaurids (Squamata) from the Maastrichtian Phosphates of Morocco: Biodiversity, palaeobiogeography and palaeoecology based on tooth morphoguilds
Authors:
Bardet et al
Abstract:
Mosasaurid squamates are the most numerically abundant, and taxonomically/ecologically diverse clade of marine amniotes represented in the Maastrichtian Phosphates of Morocco. With few exceptions, they are faunally typical of the Southern Mediterranean Tethys Margin (around palaeolatitude 25°N) and range from the base to the top of the stage. The Moroccan assemblages include at least 7 genera and 10 species representing a broad spectrum of sizes and morphologies that illustrate several ecological trends. Noteworthy is the predominance of Mosasaurinae which are widespread in contemporaneous outcrops worldwide and constitute 80% and 70% of the total genus/species number respectively. In contrast, Halisauromorpha and Russellosaurina (plioplatecarpines) are scarce and tylosaurines are presently unknown. All of the Moroccan mosasaurids exhibit characteristic tooth morphologies and can be placed into resource partitioning morphoguilds indicative of adaptations for piercing, crushing or cutting. Medium to large predators are found to distribute along the ‘Crush’-‘Cut’ axis of the morphoguild projection, and a new ‘Crush-Cut’ guild, previously unrecognised amongst Mesozoic marine amniotes, accommodates several Prognathodon species. Also of importance is the lack of mosasaurids along the ‘Pierce’-‘Crush’ axis, potentially inferring that these ecological niches were occupied by other marine vertebrates such as selachians and plesiosaurs. In addition, the relative abundance of mosasaurids throughout the Maastrichtian series of the Gantour Basin evidences direct ecological competition or predation phenomena.
Five Million Years After Permian Extinction Marine Ecosystem More Complex Than Anticipated
Coprolites from the upper Osawa Formation (upper Spathian), northeastern Japan: Evidence for predation in a marine ecosystem 5 Myr after the end-Permian mass extinction
Authors:
Nakajima et al
Abstract:
Lower Triassic marine deposits, which can potentially provide important information on the diversity and trophic structure of marine ecosystems following the end-Permian mass extinction, are rarely exposed in the world. Given the sparse body fossil record from the Lower Triassic, non-body fossil evidences, such as trace fossils for example, may provide additional windows on fossil ecosystems. Herein, the authors recently found dark, amorphous lumps of various sizes, ranging from a few millimetres to approximately 7 cm in maximum dimension, from the offshore marine deposit of upper Osawa Formation (Spathian, Lower Triassic) in the South Kitakami Terrane of northeast Japan. Compared with the surrounding siliciclastic sediments, the lumps are rich in phosphate and organic carbon, and poor in silicates. Shape, mode of occurrence, bone inclusion and geochemical signatures of these lumps confirm that these are coprolites, produced not by benthic sediment feeders, but most likely by nektonic animals. Bone inclusion also suggests that carnivorous fish and/or marine reptiles, constituting the higher part of the food chain, produced at least a part of the specimens. Despite the low diversity of the known fossil vertebrates from the Osawa formation, coprolites first shed light on the predator–prey interactions in the marine ecosystem in South Kitakami Terrane 5 Myr after the end-Permian mass extinction.
The Superior Craton Breakup & Reassembled in the NeoArchean
Neoarchean disaggregation and reassembly of the Superior craton
Authors:
Bédard et al
Abstract:
The southern and western Superior craton of Canada (SWSC) is widely considered to be a tectonic collage accreted from north to south by multiple coeval subduction zones. We propose an alternative non-plate tectonic scenario where SWSC continental fragments are not exotic but derived by partial disaggregation of a heterogeneous older (Superior I) craton in response to a mantle overturn event that started at ca. 2780 Ma. During overturn, radial mantle outflow stretched and disaggregated the lithosphere to create the concentric Neoarchean fabric of the Superior craton, the southern part of which (SWSC) broke up into ribbon continents separated by oceanic tracts. Neoarchean calc-alkaline magmas record interaction between plume-related magma and older crust. A change in the mantle flow field at ca. 2720 Ma caused southward drift of the Northern Superior cratonic block as a result of mantle traction on its lithospheric keel, and SWSC terranes accreted to its leading edge.
Greenland Ice Sheet More Climate Sensitive Than Expected
A new model developed by researchers at the University of Cambridge has shown that despite its apparent stability, the massive ice sheet covering most of Greenland is more sensitive to climate change than earlier estimates have suggested, which would accelerate the rising sea levels that threaten coastal communities worldwide.
In addition to assessing the impact of the increasing levels of meltwater created and spilled into the ocean each year as the climate continues to warm, the new model also takes into account the role that the soft, spongy ground beneath the ice sheet plays in its changing dynamics. Details are published today (29 September) in the journal Nature Communications.
The Greenland Ice Sheet, which is the second-largest ice sheet in the world, covers 1.7 million square kilometres - an area roughly eight times the size of the United Kingdom - and contains enough ice to raise sea levels by more than seven metres if it were to be lost altogether.
Currently, due to surface melting alone, it is losing ice at a net annual rate of 200 gigatonnes, equating to 0.6 millimetres of sea level rise. A similarly large, but ultimately more uncertain source of sea level rise is tied to a net annual ice loss caused by increased movement of the ice sheet, which results in more ice being discharged into the ocean. Globally, sea levels are rising at three millimetres annually.
Large ice sheets such as in Greenland are far from stationary. Different parts of the ice often move at different speeds, causing ice to shear, a phenomenon known as ice flow.
"When these large ice sheets melt, whether that's due to seasonal change or a warming climate, they don't melt like an ice cube," said Dr Marion Bougamont of Cambridge's Scott Polar Research Institute, who led the research. "Instead, there are two sources of net ice loss: melting on the surface and increased flow of the ice itself, and there is a connection between these two mechanisms which we don't fully understand and isn't taken into account by standard ice sheet models."
Whereas other models of the Greenland Ice Sheet typically assume the ice slides over hard and impermeable bedrock - an assumption which is largely practical and based on lack of constraints - this study incorporates new evidence from ground-based surveys, which show soft and porous sediments at the bed of the ice sheet, more like the soft and muddy bottom of a lake than a sheet of solid rock. The new study specifically identifies the intake and temporal storage of water by weak sediment beneath the ice sheet as a crucial process in governing the ice flow.
Using a three-dimensional ice sheet model, together with an observational record of surface melting produced by collaborators at Aberystwyth University, Dr Bougamont and Dr Poul Christoffersen were able to accurately reproduce how the ice sheet's seasonal movement changes in response to the amount of surface meltwater being delivered to the ground below.
Lakes which form on the surfaces of glaciers, known as supraglacial lakes, are often created during the melt season, and typically last from early June to late August. Co-author Professor Alun Hubbard of Aberystwyth University studied these lakes and found that many empty in just a matter of hours, when hydrofracturing opens up water-filled crevasses, resulting in huge amounts of water entering and flooding the subglacial environment. In warmer years, these high-discharge drainage events are expected to become even more frequent.
"Not only is the ice sheet sensitive to a changing climate, but extreme meteorological events, such as heavy rainfall and heat waves, can also have a large effect on the rate of ice loss," said Dr Christoffersen. "The soft sediment gets weaker as it tries to soak up more water, making it less resistant, so that the ice above moves faster. The Greenland Ice Sheet is not nearly as stable as we think."
While complete loss of all ice in Greenland is judged to be extremely unlikely during this century, the record extent of surface melting in the past decade clearly shows that the ice sheet is responding to Earth's changing climate.
link.
Chinese Submarine Visited Sri Lanka
A Chinese military website, ostensibly sponsored by the People’s Liberation Army, quoting Sri Lanka media has reported that a Chinese Type 039 diesel-electric Song-class submarine along with Changxing Dao, a submarine support ship from the North Sea Fleet was sighted berthed alongside at the Colombo International Container Terminal. Although the pictures of the submarine and the support vessel together in the port have not been published either by the Sri Lankan or the Chinese media, it is believed that the submarine arrived in early September just before the Chinese President Xi Jingping’s visit to Sri Lanka. The report also states that the submarine was on a routine deployment and had stopped over for replenishment. Further, a Chinese naval flotilla would call at a Sri Lankan port later in October and November.
In the past, reports about the presence of Chinese submarines in the Indian Ocean have been announced in the media. For instance, the Indian media reported that a type-093 attack nuclear submarine was on deployment (December 2013 to February 2014) in the Indian Ocean and that the Chinese Ministry of National Defense (Foreign Affairs Office) had informed the Indian military attaché in Beijing of the submarine deployment to show ‘respect for India’. Apparently, the information of the deployment was also shared with the United States, Singapore, Indonesia, Pakistan and Russia.
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Touring India's Economic Reforms & Their Consequnces
WHEN Narendra Modi’s Bharatiya Janata Party won a thumping majority for its pro-growth promises in India’s elections in May, hopes swelled that the new government would adopt economic reforms that had proved beyond the brittle coalitions of the past. Yet in defiance of the maxim that the boldest steps are best taken early, Mr Modi has so far eschewed dramatic change.
Cuts to subsidies (such as on fuel and fertilisers), which cost 2.3% of GDP last year, have been deferred at least until a committee of experts produces a fresh report to add to the existing library of studies on the subject. There is no firm timetable for a national goods-and-services tax, which would boost GDP substantially by removing barriers to trade between India’s many states. Caps on foreign direct investment in many areas, including supermarkets, remain in place. Instead the government has taken a series of small steps, ginning up India’s sluggish bureaucracy, for instance. Is the chance to reshape India’s economy slipping away already?
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Thursday, October 02, 2014
Japan Selects Fujitsu to Build Exaflop Supercomputer by 2021
Japan has chosen Fujitsu to help it regain the top spot in the global supercomputer race with an exascale machine, which at 1,000 petaflops would be about 30 times faster than the leading supercomputer today.
The electronics giant said Wednesday it will work with the Riken research center to come up with a basic design for the supercomputer that would succeed the K computer, a machine they co-developed that grabbed the No. 1 spot in June 2011.
Riken has a mandate from Japan’s Ministry of Education, Culture, Sports, Science and Technology (MEXT) to develop a next-generation supercomputer, and said it chose Fujitsu following an open bidding process to develop a “post-K supercomputer.”
Fujitsu will initially collaborate with Riken on a basic design, working towards beginning operation of the post-K computer supercomputer by April 2021.
The Riken Advanced Institute for Computational Science did not specify a performance speed or other characteristics of the machine, which it is calling the FLAGSHIP 2020 Project.
link.
My Son's Family Birthday Party
Yes, my son has joined the Cult of Star Wars. MUHAHAHA.
Star Wars is one of his two favourite movies. The other is Frozen. Go figure.
Sikorsky Unveils Raider Light-Attack Helicopter
Helicopter-maker Sikorsky Aircraft Corp. unveiled its next-generation light-attack helicopter, the S-97 Raider, during a ceremony Thursday in Florida.
The coaxial design features counter-rotating rotor blades and a push propeller, among other innovations, that will allow it to fly much faster and farther than today’s choppers.
The Raider was designed to target a potentially $16 billion Army weapons program called the Armed Aerial Scout to develop a replacement for the OH-58 Kiowa Warrior, the smallest aircraft in the U.S. fleet. The service put the acquisition effort on hold due to automatic budget cuts.
Why Boeing Beat SpaceX
Boeing Co. received consistently higher rankings than Space Exploration Technologies Corp. during NASA's recent multibillion-dollar competition to build "space taxis," according to an internal agency document.
The memo—dated Sept. 15 and reviewed by The Wall Street Journal—provides an inside look at the National Aeronautics and Space Administration's deliberations and reveals why agency officials rated Boeing's bid better across the board than the one submitted by SpaceX, as the smaller company is called.
Chicago-based Boeing ended up with a contract worth up to $4.2 billion, versus $2.6 billion for Southern California-based SpaceX. The goal is to use company-owned and operated spacecraft to start transporting astronauts into orbit by 2017.
The rivalry was widely viewed as the closest head-to-head matchup yet between a big traditional aerospace contractor such as Boeing and a so-called new-space upstart represented by SpaceX.
But the 29-page document, signed by NASA's associate administrator William Gerstenmaier the day before the awards were announced, depicts more of a one-sided contest. Boeing ranked above SpaceX in every major category, from technical maturity to management competence to likelihood of sticking to a timetable.
Boeing's submission was considered "excellent" for "mission suitability," whereas SpaceX got a "very good" ranking. The numerical scores for that category, according to one person familiar with the details, were separated by more than 60 points out of a possible 1,000. The document shows Boeing also garnered the highest ranking of "excellent" for technical approach and program management, compared with "very good" rankings for SpaceX.
Based on Boeing's performance on a preliminary contract, NASA concluded it had "very high confidence" in that company's likelihood of delivering what it promised—the highest ranking possible.
Despite SpaceX's historic achievement of becoming the first commercial entity to put a capsule into orbit and ferry NASA cargo to and from the international space station, the agency had somewhat less assurance in the company's ability to perform, also based on performance on its own preliminary contract. NASA determined it had "high confidence" in SpaceX's pledges.
link.
Did the Breakup of Pangea Drive the Evolution of Angiosperms During the Cretaceous?
Tectonic-driven climate change and the diversification of angiosperms
Authors
Chaboureau et al
Abstract:
In 1879, Charles Darwin characterized the sudden and unexplained rise of angiosperms during the Cretaceous as an “abominable mystery.” The diversification of this clade marked the beginning of a rapid transition among Mesozoic ecosystems and floras formerly dominated by ferns, conifers, and cycads. Although the role of environmental factors has been suggested [Coiffard C, Gómez B (2012) Geol Acta 10(2):181–188], Cretaceous global climate change has barely been considered as a contributor to angiosperm radiation, and focus was put on biotic factors to explain this transition. Here we use a fully coupled climate model driven by Mesozoic paleogeographic maps to quantify and discuss the impact of continental drift on angiosperm expansion and diversification. We show that the decrease of desertic belts between the Triassic and the Cretaceous and the subsequent onset of long-lasting humid conditions during the Late Cretaceous were driven by the breakup of Pangea and were contemporaneous with the first rise of angiosperm diversification. Positioning angiosperm-bearing fossil sites on our paleobioclimatic maps shows a strong match between the location of fossil-rich outcrops and temperate humid zones, indicating that climate change from arid to temperate dominance may have set the stage for the ecological expansion of flowering plants.
Large Lunar Subsurface Volcanic Structures Uncovered by Grail
Subsurface structures of large volcanic complexes on the nearside of the Moon: A view from GRAIL gravity
Authors:
Huang et al
Abstract:
The lunar nearside large volcanic complexes, such as the Rümker Hills, Aristarchus Plateau, and Marius Hills are likely sites of intense and sustained magmatic activity. These volcanic complexes, recently proposed to be shield volcanoes, are generally located at regionally high elevations and some feature relatively well-localized positive gravity anomalies. Applying localized spectral analyses on high-resolution gravity data obtained from the Gravity Recovery and Interior Laboratory (GRAIL) mission and topography data returned from the Lunar Reconnaissance Orbiter (LRO) spacecraft, we study the subsurface structures of these volcanic complexes. The gravity signal is predicted using a thin elastic lithospheric model that considers both surface and subsurface loads. Best-fit crustal and load densities show that the topographic highs of Rümker Hills, Marius Hills, Gardner and Kepler are mainly composed of material that has a density of more than 2850 kg m-3, which is consistent with that of emplaced igneous rocks. Both the Aristarchus Plateau and Hortensius have relatively lower crustal and surface load densities, with mean values around 2550 kg m-3, which are well consistent with the average bulk density of the lunar highland crust. These results, together with evidence of multiple volcanic edifices on the surface, suggest that the shallow crusts of the Rümker Hills, Marius Hills, Gardner and Kepler are mainly composed of dense intrusive/extrusive magmatic units, and those of the Aristarchus Plateau and Hortensius are mainly composed of low density materials with only small amounts of superimposed volcanic material. To further constrain the subsurface structures beneath these volcanic complexes, we analyze the Bouguer gravity anomalies for these regions. Results show that dense materials that might be solidified intrusions exist beneath Rümker Hills, Marius Hills, Gardner and Prinz, but no substantial dense materials have been detected beneath the Aristarchus Plateau, Hortensius, Kepler or Cauchy. The different subsurface structures among these large volcanic complexes suggest that the volcanism style at the lunar nearside is different from each other, even for those formed at the same geological time.
Distinguishing Geofacts From Artifacts
Comparative methods for distinguishing flakes from geofacts: a case study from the Wenas Creek Mammoth site
Authors:
Lubinski et al
Abstract:
Archaeologists have long struggled with distinguishing lithic materials modified by humans (artifacts) from natural objects (e.g., geofacts or zoofacts). This problem is especially difficult for finds of small numbers of flake-like lithic specimens, and particularly for very old finds. We attempt to address the artifact versus geofact problem at a paleontology site by employing three systematic and objective tests on the two recovered possible artifacts. First, they are compared with debitage attributes typically expected of artifacts and geofacts based on published experimental and actualistic data. Second, they are compared in terms of nine of these attributes with a toolstone sample from the site excavation matrix. Third, the two possible artifacts are scored for these nine attributes and graphed against the toolstone matrix sample and two samples of flintknapped debitage assemblages. In all three comparisons, the two specimens are more like artifacts than geofacts. While this does not prove the specimens are artifacts, it at least shows they cannot be easily dismissed as the sort of geofacts typically expected in the site matrix. We argue that this distinction is an important first step in the evaluation of possible lithic artifacts.
Eousdryosaurus nanohallucis: A new Dryosaurid Ornithopod From Kimmeridgian Jurassic
A new dryosaurid ornithopod (Dinosauria, Ornithischia) from the Late Jurassic of Portugal
Authors:
Escaso et al
Abstract:
A new dryosaurid ornithopod, Eousdryosaurus nanohallucis, gen. et sp. nov., is described here based on a single specimen from the Late Jurassic Alcobaça Formation of Portugal. Eousdryosaurus nanohallucis is distinguished from all other dryosaurids by eight autapomorphic features and an unique combination of characters, some of which are also shared by other dryosaurids. Eousdryosaurus is linked with Dryosauridae, because the fourth trochanter is proximally placed and widely separated from the scar for the insertion of the M. caudifemoralis longus, which is restricted to the medial surface of the femoral shaft. Phylogenetic analysis nests Eousdryosaurus in an unresolved polytomy at the base of Dryosauridae together with Callovosaurus, Dryosaurus, and Kangnasaurus. The complete pes of Eousdryosaurus, which has a phalangeal formula of 1-3-4-5-0, supports the putative autapomorphic reduction of the dryosaurid pes that also occurs in parallel in more derived ornithopods.
When Did Plate Tectonics Start?
The mystery of what kick-started the motion of our earth's massive tectonic plates across its surface has been explained by researchers at the University of Sydney.
"Earth is the only planet in our solar system where the process of plate tectonics occurs," said Professor Patrice Rey, from the University of Sydney's School of Geosciences.
"The geological record suggests that until three billion years ago the earth's crust was immobile so what sparked this unique phenomenon has fascinated geoscientists for decades. We suggest it was triggered by the spreading of early continents then eventually became a self-sustaining process."
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EU Can't Deal With Disintegrating Members
THE demonstrations that led to the fall of the Berlin Wall came out of nowhere, says Günther Dauwen, and had consequences nobody could foresee. Observing the proceedings in Scotland last week, he wondered if something similar might be brewing. From a quiet fourth-floor office in Brussels Mr Dauwen runs the European Free Alliance (EFA), a rum assortment of 40 regional political groups, including the Scottish National Party (SNP), that seek greater autonomy, or, in some cases, independence, from existing countries. From the plains of Silesia to the beaches of Corsica, reckons Mr Dauwen, there is a growing clamour for power among Europe’s long-neglected regions. Scotland is a “beacon” for such places; that its independence referendum was achieved at all encouraged others to think “Yes, we can!”, even though the outcome was negative. In the run-up to the vote the EFA’s website nearly crashed under the weight of traffic.
Watching the streets of Edinburgh filling up with Saltire-waving Catalans, Flemings and South Tyroleans (not to mention Québécois, Kurds and Taiwanese) last week, a visitor might have been forgiven for assuming that something was stirring in Europe. Some commentators fretted about the prospect of “balkanisation” across the continent. Yet although parts of Europe may one day drift towards dissolution, and Catalonia is trying to hold a vote on its future, the Scottish effect was overdone. Pro-independence campaigners in Flanders or the Veneto will have taken heart from the Scottish campaign, but given the different constitutional arrangements of Belgium and Italy they will struggle to draw useful lessons from it. And it will take a lot more to rouse the good burghers of Bavaria or Frisia from their slumbers.
Outside Britain, the biggest impact of a Scottish vote for secession would have been felt within the European Union. Ever since it adopted “Independence in Europe!” as a slogan in 1988, EU membership has been central to the SNP’s proposition. For small nations, the prospect of staying in a giant trading block with its own foreign policy and currency makes the idea of statehood less daunting. In contrast to what is perceived as an oppressive multinational state, it may offer space for identities to flourish. Asked in 2007 if his country wanted to establish a “Greater Albania”, an Albanian official referred to the EU symbol: “Yes we do. It has a blue flag and gold stars on it.”
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Wednesday, October 01, 2014
DARPA Develops Electronics Anti Counterfeit Technology
Any counterfeit high-tech goods are a serious safety threat to people and cybersecurity as well as a problem for system reliability and performance.
The Defense Advanced Research Projects Agency said this week one of its contractors, working on one of the agency’s anti-counterfeit projects has developed and deployed what it calls an Advanced Scanning Optical Microscope that can scan integrated circuits by using an extremely narrow infrared laser beam, to probe microelectronic circuits at nanometer levels, revealing information about chip construction as well as the function of circuits at the transistor level.
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DDG-1000 Zumwalt Fires up gas Turbines
The Navy has started the massive gas turbines in its latest class of guided missile destroyer ahead of the ship’s commissioning next year, Naval Sea Systems Command (NAVSEA) announced on Thursday.
The first-in-class Zumwalt (DDG-1000) fired up the two Rolls Royce MT-30 and two smaller Rolls-Royce RR450 gas turbines this week as part of testing the ships new integrated power system (IPS) that will use the combined 80 mega-watt power to power the ship and its new advanced indication motors (AIM).
“Light-off of DDG-1000’s generators is a critical step forward in the activation, test, and trials of the ship’s systems,” said Capt. Jim Downey, DDG-1000 program manager in the Thursday statement.
Unlike traditional gas turbine arrangements on U.S. naval ships, the 36 mega-watt MT-30s and 3.8 mega-watt RR450s will drive a ship-wide electrical grid. Instead of having a direct mechanical connection to the ship’s propellers or water jets, the turbines will route power electrically to complex electrical motors that will drive the ship — crucial to the Navy’s IPS concept.
IPS is the Navy’s most mature expression of the so-called decades-old electric ship concept.
The core of the idea is by removing the direct mechanical connection from the turbines commanders have more options to route power to weapon systems or sensors.
Through IPS the amount of raw power is increased making the three planned Zumwalts ideal test platforms for next generation weapons like high energy lasers or electro magnetic railguns.
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US Navy Needs Triton, Poseidon & UCLASS for ISR
The future of Navy long-range reconnaissance, the recently arrived MQ-4C Triton drone, sprawls across its hangar here, with a wingspan 13 feet wider than a Boeing 737 but a body that’s 80 percent lighter.
Designed for 24-hour-plus patrols at 50,000 feet, Triton still can’t do the job by itself, say both the program manager and the admiral in charge of all Navy drones. It will provide the high-altitude, theater-spanning coverage that cues more tactically-focused recon aircraft to zoom in (in both senses of the word). Primarily, that means the manned, land-based P-8 Poseidon and the Unmanned Carrier-Launched Airborne Surveillance & Strike (UCLASS) drone. That’s three tricky balls for the Navy to keep in the air at once, especially in a time of tightening budgets:
The P-8 entered service late last year and is meant to work intimately with Triton. But the equipment to let a P-8 crew see all of a Triton’s sensor data and to remotely control the drone “is unfunded at this point,” Capt. Jim Hoke, the Triton program manager, admitted to visiting reporters last week.
As for Triton, as of late October all three aircraft built so far will be at Pax River for testing. A fourth test aircraft was cut for lack of funds, and an important collision-avoidance radar is behind schedule. The drone will enter operational service in late 2017, on Guam, but the planned buy of 68 aircraft is in some doubt. We can probably get by with fewer, Hoke told reporters, because Triton will be more reliable and spend less time in maintenance than the planning models predict.
Meanwhile, the controversial UCLASS program has not yet asked industry to submit final designs: Its official Request For Proposals (RFP) is delayed pending a top-level review of the 2016 budget, because critics in both Congress and the Pentagon argue the Navy’s requirements focus too much on “surveillance” at the expense of “strike.”
We need all three aircraft, Rear Adm. Mathias Winter insisted when I got him alone during the Pax River visit. But, I asked, echoing the skeptics, why buy two different intelligence, surveillance, and reconnaissance (ISR) drones? In essence, his answer was that the Triton is designed to meet the theater combatant commander’s needs, while UCLASS will work directly for the carrier strike group commander.
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Environmental Changes in the Western Interior Seaway Across the Cenomanian/Turonian Cretaceous Boundary
Paleoenvironmental and paleoceanographic changes across the Cenomanian–Turonian Boundary Event (Oceanic Anoxic Event 2) as indicated by foraminiferal assemblages from the eastern margin of the Cretaceous Western Interior Sea
Authors:
Elderbak et al
Abstract:
Two sites near the eastern margin of the Cretaceous Western Interior Sea (WIS) were investigated. The section at Cuba, Kansas (CK) is ~ 630 km east of the GSSP for the Cenomanian/Turonian boundary at Rock Canyon, Colorado (RC), and the section near Sioux City, Iowa (SCI) is ~ 315 km northeast of the Cuba site. Surprisingly, planktic foraminifera dominate all the studied samples despite the relative proximity of the sites to the paleo-shoreline and presumed neritic water depths. Such dominance suggests inhospitable benthic environments, and benthic foraminiferal assemblages indicate that seafloor oxygen in the WIS decreased eastward. Therefore, the hypothesis of an influx of freshwater into the WIS from the western margin forming a fresh water cap that diminished eastward is not supported. Benthic foraminifera are scarce in most studied samples and species diversity is low. In the CK section, diversity and abundance increase abruptly in the uppermost Cenomanian Benthonic Zone at the initiation of the δ13Corg positive excursion marking the onset of Oceanic Anoxic Event (OAE 2). In the SCI section, however, the Benthonic Zone is recognized only by presence of Nodosaria bighornensis that has a stratigraphic range restricted to this interval; other benthic taxa are very rare or absent. The favorable conditions of the Benthonic Zone were short-lived. While relatively diverse planktic foraminiferal assemblages, including keeled species, characterize the initial δ13C excursion at the CK site, dwarfed specimens of Heterohelix and Hedbergella dominate the assemblages at the more proximal Sioux City site. Furthermore, most of the biostratigraphic events recognized in the basin center RC section can be traced into the CK section, but not into the SCI section, including the Rotalipora spp. and Globigerinelloides bentonensis extinctions, the Heterohelix shift event, and the brief benthic recovery event. Correlation between eastern WIS sites shows that the SCI section is thicker, suggesting a major sediment source to the east. This may explain the inhospitable benthic conditions and development of a ‘dead zone’ (seasonal hypoxia) analogous to the modern shelf of the northern Gulf of Mexico proximal to active discharge of the Mississippi River. Development of estuarine circulation in the WIS provided the eastern part of the basin with input of calcareous plankton from the south including planktic foraminifera. Foraminiferal assemblages, total organic carbon (TOC), and δ13C data of the studied sections suggest a two-fold history of Greenhorn transgression and OAE 2 development. The initial phase is a global signal characterized by a positive δ13C excursion, low TOC values, and high foraminiferal species diversity. The second phase is characterized by overprinting by local conditions in the WIS, including high fluvial input, relatively high TOC values, and low foraminiferal species diversity. These findings suggest that the eastern margin records unique depositional and biotic environments further revealing the dynamic and complex nature of the WIS and its sedimentary cycles.
Asteroid 2014 OL339: Yet Another Earth Quasi-Moon
Asteroid 2014 OL339: yet another Earth quasi-satellite
Authors:
de la Fuente Marcos et al
Abstract:
Our planet has one permanently bound satellite -the Moon-, a likely large number of mini-moons or transient irregular natural satellites, and three temporary natural retrograde satellites or quasi-satellites. These quasi-moons -(164207) 2004 GU9, (277810) 2006 FV35 and 2013 LX28- are unbound companions to the Earth. The orbital evolution of quasi-satellites may transform them into temporarily bound satellites of our planet. Here, we study the dynamical evolution of the recently discovered Aten asteroid 2014 OL339 to show that it is currently following a quasi-satellite orbit with respect to the Earth. This episode started at least about 775 yr ago and it will end 165 yr from now. The orbit of this object is quite chaotic and together with 164207 are the most unstable of the known Earth quasi-satellites. This group of minor bodies is, dynamically speaking, very heterogeneous but three of them exhibit Kozai-like dynamics: the argument of perihelion of 164207 oscillates around -90 degrees, the one of 277810 librates around 180 degrees and that of 2013 LX28 remains around 0 degrees. Asteroid 2014 OL339 is not currently engaged in any Kozai-like dynamics.
Is There Evidence of Paleolithic Domestication of Dogs?
In search of Paleolithic dogs: a quest with mixed results
Author:
Morey
Abstract:
Archaeological evidence has long placed the origins of the domestic dog (Canis lupus familiaris) just prior to the beginning of the Holocene Epoch, some 12,000–15,000 years ago. Some studies of genetic profiles of modern canids have, however, suggested a much earlier origin, dating to Paleolithic times and perhaps exceeding 100,000 years. With such studies as a backdrop, cases have been made recently on archaeological grounds for Paleolithic dogs that in certain cases exceed 30,000 years old. When examined systematically, however, some such studies exhibit conceptual and methodological flaws, calling into serious question the accuracy of the cases advanced. At least one recent study highlights that difficulty. When a series of cases for putative Paleolithic dogs is assessed, convincing cases for such dogs are confined to about the past 15,000 years, or latest Paleolithic times. Further developments on certain specific fronts may change that, but for the time being the longstanding archaeological understanding of the dog domestication time frame continues to be reasonably accurate. Recent molecular genetic studies are converging on that temporal framework as well. Archaeologists need not be automatically swayed by ongoing changes in molecular genetic profiles.
Colymbosaurus megadeirus: A Reassessment of Kimmeridgian Jurassic Plesiosaur Paleodiversity
Anatomy of Colymbosaurus megadeirus (Reptilia, Plesiosauria) from the Kimmeridge Clay Formation of the U.K., and high diversity among Late Jurassic plesiosauroids
Authors:
Benson et al
Abstract:
We describe the syntype postcranial skeletons of the cryptoclidid plesiosauroid Colymbosaurus megadeirus. C. megadeirus is the type species of Colymbosaurus, and one other valid species, C. svalbardensis, is known. Although it is in widespread usage, C. trochanterius is a not valid species, although the presence of an anteroposteriorly oriented ridge bisecting the distal surfaces of the holotype humerus allows its referral to Colymbosaurus sp. Some specimens previously referred to C. trochanterius, including the holotype of ‘Plesiosaurus’ manselii, lack this feature, or show other differences from our hypodigm, suggesting that they are taxonomically distinct from Colymbosaurus, and countering previous suggestions that the Kimmeridge Clay Formation represents a depauperate plesiosauroid fauna. Substantial differences between the atlas-axis complexes and cervical vertebrae of Kimmerosaurus langhami, ‘Plesiosaurus’ manselii, C. megadeirus, and specimens referred here to cf. Spitrasaurus indicate that at least four plesiosauroid taxa were present in the Kimmeridge Clay Formation. This proposition is also supported by coracoid morphotypes, and demonstrates that Late Jurassic plesiosauroids were taxonomically diverse. Most Late Jurassic–Early Cretaceous cryptoclidids belong to a monophyletic Colymbosaurinae, but Kimmerosaurus and its sister taxon Tatenectes originated independently from Middle Jurassic cryptoclidids.
Three Evolutionary Radiations of Sharks During the Famennian Devonian
Paleogeographical and paleoecological constraints on paleozoic vertebrates (chondrichthyans and placoderms) in the Ardenne Massif: Shark radiations in the Famennian on both sides of the Palaeotethys
Authors:
Derycke et al
Abstract:
Three chondrichthyan radiations are registered in the Famennian of the Ardenne Massif (Belgium). These radiations are already observed in Morocco and in the Carnic Alps, their acme being related with the early expansa transgression. Comparisons of univariate statistical descriptors like Margalef richness and Shannon–Wiener diversity index show variations between both margins of the Paleotethys, variations interpreted in terms of trophic relationships. The Ardenne area, a northern shallow carbonate platform is characterized during the Famennian by endemic shark taxa with durophagous dentition. The southern open deep-sea area, the Variscan Sea, contains large placoderms probably disclosing a negative feedback on “cladodont” chondrichthyans. This supports the hypothesis that the Armorica platelet behaved like a barrier between the central southern Laurussia and northern Gondwana.
Hypothesis: Lichen-Fungal Colonization of the Land Drove NeoProterozoic Oxidation Event?
Hypothesized link between Neoproterozoic greening of the land surface and the establishment of an oxygen-rich atmosphere
Author:
Kump
Abstract:
Considerable geological, geochemical, paleontological, and isotopic evidence exists to support the hypothesis that the atmospheric oxygen level rose from an Archean baseline of essentially zero to modern values in two steps roughly 2.3 billion and 0.8–0.6 billion years ago (Ga). The first step in oxygen content, the Great Oxidation Event, was likely a threshold response to diminishing reductant input from Earth’s interior. Here I provide an alternative to previous suggestions that the second step was the result of the establishment of the first terrestrial fungal–lichen ecosystems. The consumption of oxygen by aerobes respiring this new source of organic matter in soils would have necessitated an increase in the atmospheric oxygen content to compensate for the reduced delivery of oxygen to the weathering environment below the organic-rich upper soil layer. Support for this hypothesis comes from the observed spread toward more negative carbon isotope compositions in Neoproterozoic (1.0–0.542 Ga) and younger limestones altered under the influence of ground waters, and the positive correlation between the carbon isotope composition and oxygen content of modern ground waters in contact with limestones. Thus, the greening of the planet’s land surfaces forced the atmospheric oxygen level to a new, higher equilibrium state.
Great Barrier Reef Calcification dropped 40% Over 35 Years due to Climate Change, Ocean Acidification
An expedition from the Hebrew University of Jerusalem and the Carnegie Institute of Science has measured a roughly 40% reduction in the rate of calcium carbonate deposited in Australia's Great Barrier Reef in the last 35 years — a scenario that could damage the reef framework and endanger the entire coral ecosystem.
Coral reefs are the most ecologically diverse and productive ecosystem in the ocean, with rich and diverse communities of fish, corals and mollusks making them a major attraction for marine and underwater tourism. Producing almost 50% of the net annual calcium carbonate in the oceans, corals play an important role in the global carbon cycle.
The ecological success of coral reefs depends on their calcium carbonate (CaCO3, limestone) structures that function as a huge filter to obtain plankton from the open ocean. Yet recent environmental changes including coastal nutrient pollution, global warming and ocean acidification caused by atmospheric CO2 increasingly threaten the existence of these unique ecosystems.
To better understand the effect of acidification on coral growth decline, Hebrew University scientists led by Prof. Jonathan Erez and Prof. Boaz Lazar at the Fredy and Nadine Herrmann Institute of Earth Sciences, together with Carnegie Institute colleagues Dr. J. Silverman and Dr. K. Caldeira, carried out a community metabolism study in Lizard Island at the Great Barrier Reef in Australia.
The researchers compared calcification rates documented in 2008 and 2009 to those measured using similar techniques in 1975-6. Despite the fact that the coral cover remained similar, the researchers found that the recent calcification rates had decreased by between 27% and 49%. These lower rates are consistent with predictions that took into account the increase in CO2 between the two periods, suggesting that ocean acidification is the main cause for the lower calcification rate at Lizard Island. The prediction of how coral reef communities should respond to ocean acidification comes from work conducted by Dr. Silverman for his PhD at the Hebrew University, with Dr. Lazar and Prof. Erez as his advisers.
While previous studies on individual reef building corals have shown that they lower their calcification rates in response to ocean acidification, in the present study this was demonstrated for the whole community. These findings suggest that coral reefs are now making skeletons that are less dense and more fragile. While they still look the same, these coral reefs are less able to resist physical and biological erosion.
link.
Japan's JS Izumo: Helicopter Destroyer or Heli Carrier? Enters Sea Trials
Japan’s largest warship since World War II has left for its first set of sea trials last week ahead of entering the Japanese Maritime Self Defense Force (JMSDF)fleet next year.
JS Izumo (DDH-183) departed Tokyo Bay on Sept. 23, as seen as in a video on YouTube, for the first round of what will be about six months of sea trials ahead of the ship’s commissioning next year, a JMSDF official told Jane’s Defence Weekly on Monday.
The 24,000-ton helicopter carrier is the first of two planned ships. Izumo will enter the JMSDF force next year. DDH-184 will enter the fleet in 2017, according to the Naval Institute’s Combat Fleet’s of the World.
link.
Rise of the Military and Space Advocate Factions in China
Much has been written about the growing influence of People’s Liberation Army (PLA) generals on China’s foreign policy. Little has been said about military entrepreneurs and other non-combatant PLA personnel moving into China’s domestic governance. Under Chinese President Xi Jinping, an unprecedented number of senior cadres from the country’s labyrinthine jungong hangtian (military-industrial and space-technology) complex are being inducted to high-level Party-government organs or transferred to regional administrations. Given the perception that officials with military backgrounds tend to be more conservative and unquestionably loyal to the Chinese Communist Party (CCP) leadership, the partial militarization of the civilian Party-state apparatus will have far-reaching implications for the prospects of political and economic reforms, among others.
link.
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