понедельник, 29 апреля 2019 г.

2019 April 29 N11: Star Clouds of the LMC Image Credit: NASA,…

2019 April 29

N11: Star Clouds of the LMC
Image Credit: NASA, ESA; Acknowledgement: Josh Lake

Explanation: Massive stars, abrasive winds, mountains of dust, and energetic light sculpt one of the largest and most picturesque regions of star formation in the Local Group of Galaxies. Known as N11, the region is visible on the upper right of many images of its home galaxy, the Milky Way neighbor known as the Large Magellanic Clouds (LMC). The featured image was taken for scientific purposes by the Hubble Space Telescope and reprocessed for artistry by an amateur to win a Hubble’s Hidden Treasures competition. Although the section imaged above is known as NGC 1763, the entire N11 emission nebula is second in LMC size only to the Tarantula Nebula. Compact globules of dark dust housing emerging young stars are also visible around the image. A new study of variable stars in the LMC with Hubble has helped to recalibrate the distance scale of the observable universe, but resulted in a slightly different scale than found using the pervasive cosmic microwave background.

∞ Source: apod.nasa.gov/apod/ap190429.html

Scientists take a ‘metamaterials’ approach to earthquake damage…

Scientists take a ‘metamaterials’ approach to earthquake damage http://www.geologypage.com/2019/04/scientists-take-a-metamaterials-approach-to-earthquake-damage.html

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Figure 1. Equatorial and Galactic coordinate distribution of the stars observed with Gemini North and Gemini South in poor weather conditions.

The Gemini telescopes helped identify low-metallicity stars by gathering medium-resolution spectroscopic GMOS data for 666 bright stars under poor weather conditions. These data provide a unique opportunity to explore the chemical evolution of the Milky Way and look at the enrichment of star-forming gas clouds in the early Universe. 


Note: Below are highlights from an article published in the April 2019 issue of GeminiFocus by Principal Investigator Vinicius Placco of the University of Notre Dame. The original papers were published in The Astrophysical Journal and The Astronomical Journal

Low-metallicity stars (stars with less than 1% of the elements heavier than Hydrogen and Helium than the Sun contains) are the Rosetta Stones of stellar astrophysics. Encoded in the atmosphere of these low-mass, long-lived relics are the signatures of the processes by which the first chemical elements were cooked up, perhaps as early as a few tens of millions of years after the Big Bang. These stars are believed to be the direct descendants of the first stars to be born in the Universe, which were massive and short-lived. Hence, second-generation, low-metallicity stars are the artifacts which help us write the ancient chemical history of the Universe.

In particular, the Extremely Metal-Poor stars (EMP — with iron abundances of 1/1,000 of the solar value) are believed to carry in their atmospheres the chemical fingerprints of the evolution of as few as one first-generation massive star. EMP stars are intrinsically rare (less than 30 stars identified to date with iron abundances of 1/10,000 of the solar value) and the majority (more than 60%) show a very strong molecular carbon signature in their optical spectrum. The low-metallicity and strong carbon also affect the colors of these stars in optical wavelengths. Taking advantage of this, we were able to preselect bright candidates from two public stellar databases — the RAdial Velocity Experiment (RAVE) and the Best & Brightest Survey (B&B). We then used the Gemini Multi-Object Spectrograph (GMOS; North and South) with the B600 gratings and 1-arcsecond slits to obtain the spectra of 666 stars (see Figure 1).

In total, seven GMOS Poor Weather programs were executed (three in the North and four in the South) spanning four semesters (from 2015A to 2016B). Those programs had 310 hours of allocated time, and, assuming the 666 targets took 222 hours of observing time, the efficiency was around 72%, meaning that only 28% of the already poor weather was lost, which is a great accomplishment for the program and the Observatory.

The spectra gathered at Gemini/GMOS are of sufficient quality (signal-to-noise ratios and spectral resolution) to allow for the determination of stellar atmospheric parameters: effective temperature, surface gravity, metallicity, and carbon abundance. A subset of these stars were then re-observed in higher-resolution, so it was possible to determine their full chemical abundance pattern. There is already a study published based on the extremely metal-poor star J2005-3057, first identified at Gemini (Cain et al., 2018). We are also gathering high-resolution data for the most carbon-enhanced stars identified by Gemini and the results are also promising. In the near future, such bright stars will be perfect targets for high-resolution spectroscopic follow-up with GHOST, which will be a great asset in pushing these efforts forward.

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When India Slammed Into Asia…

When India Slammed Into Asia http://www.geologypage.com/2019/04/when-india-slammed-into-asia.html

Diamonds reveal how continents are stabilized, key to Earth’s…

Diamonds reveal how continents are stabilized, key to Earth’s habitability http://www.geologypage.com/2019/04/diamonds-reveal-how-continents-are-stabilized-key-to-earths-habitability.html

Mysterious Large-Magnitude Eruption that Covered the…

Mysterious Large-Magnitude Eruption that Covered the Mediterranean http://www.geologypage.com/2019/04/mysterious-large-magnitude-eruption-that-covered-the-mediterranean.html

Major deep carbon sink linked to microbes found near volcano…

Major deep carbon sink linked to microbes found near volcano chains http://www.geologypage.com/2019/04/major-deep-carbon-sink-linked-to-microbes-found-near-volcano-chains.html

What does the future of Kilauea hold?…

What does the future of Kilauea hold? http://www.geologypage.com/2019/04/what-does-the-future-of-kilauea-hold.html

Mining : What is Mining? What are the 4 mining methods?…

Mining : What is Mining? What are the 4 mining methods? http://www.geologypage.com/2019/04/mining-what-is-mining-what-are-the-4-mining-methods.html

Major deep carbon sink linked to microbes found near volcano chains

Up to about 19 percent more carbon dioxide than previously believed is removed naturally and stored underground between coastal trenches and inland chains of volcanoes, keeping the greenhouse gas from entering the atmosphere, according to a study in the journal Nature.

Major deep carbon sink linked to microbes found near volcano chains
Calcite deposits near a waterfall in Costa Rica [Credit: Peter Barry]

Surprisingly, subsurface microbes play a role in storing vast amounts of carbon by incorporating it in their biomass and possibly by helping to form calcite, a mineral made of calcium carbonate, Rutgers and other scientists found. Greater knowledge of the long-term impact of volcanoes on carbon dioxide and how it may be buffered by chemical and biological processes is critical for evaluating natural and human impacts on the climate. Carbon dioxide is the major greenhouse gas linked to global warming.
«Our study revealed a new way that tiny microorganisms can have an outsized impact on a large-scale geological process and the Earth’s climate,» said co-author Donato Giovannelli, a visiting scientist and former post-doc in the Department of Marine and Coastal Sciences at Rutgers University-New Brunswick. He is now at the University of Naples in Italy.

Major deep carbon sink linked to microbes found near volcano chains
How carbon is cycled near volcano chains [Credit: Patricia Barcala Dominguez]

Giovannelli is a principal investigator for the interdisciplinary study, which involves 27 institutions in six nations. Professor Costantino Vetriani in the Department of Marine and Coastal Sciences and Department of Biochemistry and Microbiology in the School of Environmental and Biological Sciences is one of the Rutgers co-authors. The study covers how microbes alter the flow of volatile substances that include carbon, which can change from a solid or liquid to a vapor, in subduction zones. Such zones are where two tectonic plates collide, with the denser plate sinking and moving material from the surface into Earth’s interior.
The subduction, or geological process, creates deep-sea trenches and volcanic arcs, or chains of volcanoes, at the boundary of tectonic plates. Examples are in Japan and South and Central America. Arc volcanoes are hot spots for carbon dioxide emissions that re-enter the atmosphere from subducted material, which consists of marine sediment, oceanic crust and mantle rocks, Giovannelli said. The approximately 1,800-mile-thick mantle of semi-solid hot rock lies beneath the Earth’s crust.

The Earth’s core, mantle and crust account for 90 percent of carbon. The other 10 percent is in the ocean, biosphere and atmosphere. The subduction zone connects the Earth’s surface with its interior, and knowing how carbon moves between them is important in understanding one of the key processes on Earth and regulating the climate over tens of millions of years.

The study focused on the Nicoya Peninsula area of Costa Rica. The scientists investigated the area between the trench and the volcanic arc — the so-called forearc. The research reveals that volcanic forearc are a previously unrecognized deep sink for carbon dioxide.

Source: Rutgers University [April 24, 2019]



Eclogitic diamonds formed from oceanic crust, study shows

Eclogitic diamonds formed in Earth’s mantle originate from oceanic crust, rather than marine sediments as commonly thought, according to a new study from University of Alberta geologists.

Eclogitic diamonds formed from oceanic crust, study shows
A 5-mm diamond crystal in eclogite from an unnamed South African diamond mine
[Credit: Bruce Cairncross]

Diamonds are found in two types of rocks from Earth’s mantle: peridotite and eclogite. Peridotite is the most common type of mantle rock. Eclogite forms from igneous oceanic crust that together with a thin veneer of overlying marine sediment has been brought deep into the mantle through a process known as subduction. Even though, many researchers thought eclogitic diamonds formed with carbon from marine sediment, a large carbon reservoir. The new study turns this theory on its head.
«The key indices for diamond source tracing are the ratios of stable isotopes, which are atoms that have the same proton number but different neutron number, of carbon and nitrogen in diamond,» explained Long Li, associate professor in the Department of Earth and Atmospheric Sciences and principal investigator of the study. «These isotopic ratios act as source fingerprints. Marine sediment was invoked as the source of eclogitic diamonds mainly because their highly variable carbon isotopic ratios match the signature of organic matter in sediment. But the sediment source has difficulty in explaining the highly variable nitrogen isotopic signature of eclogitic diamonds.»

The study investigated 80 drill samples of igneous oceanic crust from around the world, supplied by the International Ocean Discovery Program. The researchers, led by PhD student Kan Li, conducted extensive analyses to examine the carbon budgets and isotopic signatures of the major subducting oceanic slabs.

«We verified that the oceanic crust is a large reservoir for carbon, mostly in form of carbonate. What really surprised us is that the bulk carbonate in subducting igneous oceanic crusts in part shows a similar isotopic signature to organic matter in sediment,» said Kan Li. «It then makes much more sense for igneous oceanic crust, which also contains isotopically highly variable nitrogen, to serve as the source of eclogitic diamonds in Earth’s mantle.»

«This study addresses a long-standing puzzle in diamond genesis and the deep carbon cycle,» said Long Li. «The deep carbon cycle, a process that circulates carbon from Earth’s surface to the deep interior and back again, has strong impact on mantle chemistry and surface environment. Our study shows that oceanic crust plays a much larger role in this than previously thought.»

«This research changes the way that we think recycled carbon gets into diamonds and changes what we think about how carbon in general is recycled into the Earth. It makes us re-evaluate how diamonds are formed and what the dominant source of carbon is in both the shallow and very deepest parts of Earth’s mantle,» added Graham Pearson, professor, Henry Marshall Tory Chair, and Canada Excellence Research Chair Laureate.

The study was published in Earth and Planetary Science Letters.

Author: Katie Willis | Source: University of Alberta [April 24, 2019]



Tropical forest the size of England destroyed in 2018: report

Last year humanity destroyed an expanse of tropical forest nearly the size of England, the fourth largest decline since global satellite data become available in 2001, researchers reported Thursday.

Tropical forest the size of England destroyed in 2018: report
Indonesia’s President Joko Widodo inspects a peatland clearing that was engulfed by fire in 2015
[Credit: Romeo Gacad/AFP]

The pace of the loss is staggering — the equivalent of 30 football fields disappearing every minute of every day in 2018, or a total of 120,000 square kilometres (46,000 square miles).

Almost a third of that area, some 36,000 km2, was pristine primary rainforest, according to the annual assessment from scientists at Global Forest Watch, based at the University of Maryland.

«For the first time, we can distinguish tree cover loss within undisturbed natural rainforests, which contain trees that can be hundreds, even thousands, of years old,» team manager Mikaela Weisse told AFP.

Rainforests are the planet’s richest repository of wildlife and a critical sponge for soaking up planet-heating CO2.

Despite a slew of counter-measures at both the national and international level, deforestation has continued largely unabated since the beginning of the century.

Global forest loss peaked in 2016, fuelled in part by El Nino weather conditions and uncontrolled fires in Brazil and Indonesia.

The main drivers are the livestock industry and large-scale commodity agriculture — palm oil in Asia and Africa, soy beans and biofuel crops in South America.

Small-scale commercial farming — of cocoa, for example — can also lead to the clearing of forests.

Tropical forest the size of England destroyed in 2018: report
Logs in the forest in Xapuri, Acre State, in northwestern Brazil
[Credit: Yasuyoshi Chiba/AFP]

A quarter of tropical tree cover loss in 2018 occurred in Brazil, with the Democratic Republic of Congo and Indonesia each accounting for about 10 percent.

Malaysia and Madagascar also saw high levels of deforestation last year.

Nearly a third of primary forest destruction took place in Brazil (13,500 km2), with the Democratic Republic of Congo (4,800 km2), Indonesia (3,400 km2), Colombia (1,800 km2) and Bolivia (1,500 km2) rounding out the top five.

Madagascar lost two percent of its entire rainforest in 2018.

«The world’s forests are now in the emergency room,» said Frances Seymour, a distinguished senior fellow at the World Resources Institute, an environmental policy think tank based in Washington DC.

«The health of the planet is at stake, and band aid responses are not enough,» she added.

«With every hectare lost, we are that much closer to the scary scenario of runaway climate change.»

Globally, forests absorb about 30 percent of manmade greenhouse gas emissions, just over 11 billion tonnes of C02 a year.

Oceans are also a major «sink», soaking up another 23 percent.

Tropical forest the size of England destroyed in 2018: report
Progression of deforestation in the Brazilian Amazon, with total area by state
[Credit: Maria Scarpinelli/AFP]

Burning or clear-cutting vast tracts of tropical forest not only releases carbon into the atmosphere, it reduces the size of the sponge that can absorb CO2.

One bright spot in the report was Indonesia, which lost 3,400 km2 of primary forest in 2018 — a 63 percent drop compared to 2016.

In 2015, massive forest fires on Sumatra, Borneo and other Indonesian islands levelled 20,000 km2 and generated health-wrecking pollution over a large swathe of Southeast Asia.

In Brazil, however, trend lines are moving in the wrong direction.

«Our data shows a big spike in forest loss in 2016 and 2017 related to manmade fires,» Weisse said of Brazil.

«Shockingly, we are also seeing invasions into indigenous lands that have been immune to deforestation for years.»

Brazil’s President Jair Bolsonaro, who come into office in January, has vowed to curtail environmental regulations and allow commercial farming and mining on indigenous reserves, which comprise more than 10 percent of Brazil’s territory.

The researchers emphasised that Bolsonaro has not been in office long enough to assess the impacts of his policies on deforestation.

In West Africa, meanwhile, 70 percent of primary forest loss in Ghana and Ivory Coast occurred in protected areas, pointing up the need for stricter enforcement.

Author: Marlowe Hood | Source: AFP [April 25, 2019]



Holy Pleistocene Batman, the answer’s in the cave

Let’s say you wanted to solve a 20,000-year-old mystery, where would you start? Perhaps archaeology and geology come to mind. Or, you could sift through a 3-metre pile of bat faeces.

Holy Pleistocene Batman, the answer's in the cave
Bats flying out of an Indonesian cave for their nightly meal
[Credit: Chris Wurster]

Researchers from James Cook University in Cairns, Australia, chose the bat poo in their quest to answer to a long-standing question: why is there some much biodiversity on the islands of Sumatra, Borneo and Java, when not so long ago (geologically speaking) they were all part of one vast continent?

One theory has been that the former continent (Sundaland) was dissected by a savanna corridor. «That might explain why Sumatra and Borneo each have their own species of orang-utan, even though they were linked by land for millions of years,» Dr Chris Wurster said. «The corridor would have divided the two separate rainforest refuges, as the sea does now.»

The corridor theory has been boosted by millions of insect-eating bats, which have gathered evidence about the landscape over millennia and deposited it in layers in their caves.

«Bat poo is highly informative, and especially so in the tropics, where the climate can make some of the more traditional modes of investigation less available,» Dr Wurster said.

A three-metre pile of bat faeces at Salah Cave in Borneo gave the researchers a 40,000-year-old record composed of insect skeletons.

«We can’t tell what insects the bats were eating throughout that time, because they’re in tiny fragments, but we can read the chemistry,» Dr Wurster said.

Holy Pleistocene Batman, the answer's in the cave
Bats clustering together on the wall of an Indonesian cave
[Credit: Chris Wurster]

«Eating insects that have been feeding on tropical grasses results in faeces with a characteristic chemical imprint. It’s quite different from the result you’d get from eating insects that fed on tropical trees.»

According to the bat record the landscape around Saleh Cave (now featuring lush rainforest) was once dominated by tropical grasses.

«Combined with other cave studies in the region, this leads us to support the corridor theory, and also gives us some confidence as to the extent of the corridor,» Dr Wurster said.

The corridor could also shed light on human pre-history.

«A savanna corridor, which would be much more easily traversed than rainforest, might help to explain how people moved relatively quickly through this region and on to Australia and New Guinea.»

‘Savanna in equatorial Borneo during the late Pleistocene’ is published in the latest edition of Scientific Reports.

Dr Chris Wurster is a Senior Research Associate at James Cook University, specialising in stable isotope geochemistry.

Source: James Cook University [April 25, 2019]



Researchers trace 3,000 years of monsoons through shell fossils

The tiny shells at the bottom of Lake Nakaumi in southwest Japan may contain the secrets of the East Asia Summer Monsoon. This rainy season is fairly predictable, ushering in air and precipitation conducive to growing crops, but — sometimes without any hint — the pattern fails. Some areas of East Asia are left without rainfall, and their crops die. Other areas are inundated with rain, and their crops and homes flood.

Researchers trace 3,000 years of monsoons through shell fossils
Ostracod shells from juvenile to adult used for analysis. Ostracod is an arthropod that
has lived for 500 million years [Credit:Katsura Yamada, Shinshu University]

Ostracoda shells are smaller than the white wisp a fingernail grows over a month, yet they have recorded the effects of sunshine and climate shifts for almost 500 million years.
A team of researchers dug into the lake and the rich historical record in the shells to better understand why East Asian summer monsoons vary at the centennial scale, which should hold relatively steady. They published their results in Scientific Reports.

«The mechanisms driving the variations in East Asian summer monsoons remain unclear, so we used the oxygen isotopes from adult ostracode shells to reconstruct the variations over the last 3,000 years in southwestern Japan,» said Katsura Yamada, paper author and a professor in the department of geology and faculty of science at Shinshu University.

Researchers trace 3,000 years of monsoons through shell fossils
Ostracod shells were collected from the bottom of the lake Nakaumi
[Credit: Katsura Yamada, Shinshu University, Japan]

Yamada and the team cored sections of the lake, retrieving shells from present day to 3,000 years ago. The scientists analyzed the shells, measuring a specific ratio between slightly different versions of oxygen, called isotopes.
The isotope ratio can offer a glimpse into the atmosphere’s precise composition thousands of years ago. A higher rate of nitrogen in the atmosphere will produce a different isotope of oxygen than times when nitrogen is less abundant.

The researchers found that the primary factor of the centennial-scale variations in the East Asia summer monsoon was solar activity, also called insolation.

Researchers trace 3,000 years of monsoons through shell fossils
Ostracod shell fossils [Credit: Katsura Yamada,
Shinshu University, Japan]

«Our results and compiled data propose that insolation variation was a primary factor of the centennial-scale East Asia summer monsoon variations,» Yamada said. «However, dominant factors affecting the variations can shift according to the solar insolation decreases.»
During sunny periods, the insolation dominates the East Asian monsoon pattern. During cooling off periods, usually around glacial ice ages, other factors — such as wind patterns — took over as the dominant influencer.

«Our next goal is to clarify the relationship between East Asian monsoon variations and other climatic phenomena,» Yamada said.

Source: Shinshu University [April 25, 2019]



Mysterious volcanic ash layer blanketing Mediterranean 29,000 years ago traced to volcano...

Since the late 1970s scientists have identified the same pre-historic volcanic ash layer in sediment cores extracted from sites ranging across 150,000 square kilometres of the central Mediterranean. This widespread ash layer, dated at 29,000 years ago, blanketed the region and clearly indicated a large volcanic eruption. Whilst the region is well known for its many active volcanoes, such as Mount Vesuvius which famously destroyed Pompeii in 79 AD, scientists had failed to confidently match this older, far-ranging ash deposit to a specific volcano or eruption.

Mysterious volcanic ash layer blanketing Mediterranean 29,000 years ago traced to volcano in Naples, Italy
The caldera of the Phlegraean Fields seen from the north with the city of Naples and Vesuvius
 in the background [Credit: Google Earth]

The research, led by Dr Paul Albert, a Research Fellow in the School of Archaeology, has now identified an ash rich-eruption deposit within the city of Naples which was produced by Campi Flegrei volcano and has a chemical composition that matches the prehistoric ash layer traced across the Mediterranean region.
The work was done in partnership with international researchers, including those from the National Institute of Geophysics and Volcanology (INGV), the National Research Council in Italy, the Laboratoire des Sciences du Climat et de l’Environnement in France, and the Berkeley Geochronology Centre in the USA.

Mysterious volcanic ash layer blanketing Mediterranean 29,000 years ago traced to volcano in Naples, Italy
The Campi Flegrei caldera cluster [Credit: NASA Earth Observatory image by Jesse Allen
and Robert Simmon, using EO-1 ALI data from the NASA EO-1 team]

“Part of the challenge of reliably attributing this major ash fall event to Campi Flegrei volcano has been that there is limited evidence for a large eruption close to the volcano,” says Albert. “This is in part because a more recent large-scale eruption of the volcano buried the Naples area in a thick ash deposit, largely destroying or concealing the evidence of this older event,” says Albert.
The team used a computer-based ash dispersal model to reconstruct the size of the eruption. “By linking the thickness of the ash deposits found in Naples, to those preserved in cores from across the central Mediterranean, the model was able to demonstrate and provide important constraints on the size of this large magnitude eruption,” says Albert.

Mysterious volcanic ash layer blanketing Mediterranean 29,000 years ago traced to volcano in Naples, Italy
View of the eastern part of the populated Campi Flegrei caldera from the Camadoli Hill. The volcano is the source
of the Masseria del Monte Tuff eruption 29,000 years ago. More than 300,000 people live within this active caldera
 that has experienced more than 60 eruptions in the last 15,000 years. One of these recent eruptions formed
the small Nisida cone that is seen lying just off the mainland. The Bay of Naples and Capri
can be seen in the background [Credit: Victoria Smith]

This research positions the timing of this previously un-reported large-scale eruption of Campi Flegrei between two well-known large-scale eruptions of the volcano, at 15,000 and 40,000 years ago, drastically reducing the reoccurrence interval of large magnitude eruptions at the volcano.

The research, published in the journal Geology, also highlights the importance of considering ash fall events preserved well away from the volcano when reconstructing the timing and scale of past explosive eruptions. “Ash fall preserved hundreds of kilometers away from the volcano has been critical here in the identification and reconstruction of this large eruption at Campi Flegrei,” says Albert.

Source: Oxford University [April 25, 2019]



‘The Cuckoo Stone’ Prehistoric Monolith, Woodhenge, Wiltshire, 21.4.19.

‘The Cuckoo Stone’ Prehistoric Monolith, Woodhenge, Wiltshire, 21.4.19.

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Durrington Walls Prehistoric Complex, Wiltshire, 21.4.19.

Durrington Walls Prehistoric Complex, Wiltshire, 21.4.19.

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Overton Hill Prehistoric Round Barrows, Wiltshire, 21.4.19.

Overton Hill Prehistoric Round Barrows, Wiltshire, 21.4.19.

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Bronze Age cermonial dagger discovered in central Germany

The remains of a Bronze Age settlement have been found on the property of a recycling company in Erfurt’s industrial park GVZ during work to build a carpark.

Bronze Age cermonial dagger discovered in central Germany
Bronze dagger: The weapon dates from the Early Bronze Age andwas probably worn
 as an ornament by a local ruler [Credit: : MDR/Wolfgang Hentschel]

Archaeologist Karin Sczech suspects that the settlement could have been the centre of a regional kingdom, referring in particular to the discovery of a rare well-preserved staff dagger.
«The staff dagger is a masterpiece of the Early Bronze Age,» says Sczech. «Similar specimens are only known from six sites, mainly in Brandenburg and Poland. There the daggers are well attested as prominent grave goods or from ritually deposited hoards. The prince of Leubing also had such a dagger in his burial mound.»

The Erfurt dagger is unprecedented in its design. It has a central rib, fine embossed decoration and prominently protruding rivets. The upper part is broken off, but overall the dagger looks like new. According to Sczech the scientists still argue whether such noble daggers were used in battle or only as status symbols of the elites.

Bronze Age cermonial dagger discovered in central Germany
Excavation of post holes [Credit: MDR/Wolfgang Hentschel]

The dagger was once attached to an arm-length staff, which was probably also made of bronze and had a wooden core. The staff has not been preserved.
The dagger was discovered by excavation worker Thomas Schmidt in the debris of the bulldozer that moved the earth during the excavation.

«Unfortunately, it is no longer possible to say in which environment the dagger was lying in the ground», says Sczech. «The other finds on the site, however, point to a settlement that had existed for several centuries.»

Bronze Age cermonial dagger discovered in central Germany
The finds also include a so-called grooved hammer, which was attached to a handle with ropes
[Credit: MDR/Wolfgang Hentschel]

This also includes a large grooved stone hammer head with traces of use that was once tied to a wooden shaft with ropes.
Archaeologists have also found ceramics and other objects in the vicinity of the hammer, which clearly indicate that they are from the ‘Unetice culture’ of the Early Bronze Age.

On the basis of post holes in the ground, two parallel house layouts can be reconstructed. One of the houses, which may have been built one after the other, was at least 18 metres long. Such longhouses served both as stables and houses. These houses cannot be dated, but based on the surrounding finds, such as a typical ceramic storage vessel, it is highly probable that they are 4000 years old.

A grave with a destroyed skull and missing bones is several hundred years older and shows that the site was already inhabited in the Neolithic Age.

The grave goods, which included an axe, a blade and a stone scraper, as well as the orientation of the grave show that it is the grave of a man.

According to Sczech, it was «standard equipment» of that time — in contrast to the owner of the dagger, the dead man probably had no particular social rank.

Source: Thüringe Allgemeine [April 26, 2019]



African populations crossbred with other extinct humans

A new international study led by David Comas, principal investigator at UPF and at the Institute of Evolutionary Biology (IBE:  CSIC-UPF), demonstrates for the first time using artificial intelligence that African populations hybridized with other extinct humans. The study is published in the journal Genome Biology.

African populations crossbred with other extinct humans
From the study of the DNA of present-day African populations, an international team of scientists has found
that they had offspring with an extinct archaic population [Credit: Centre for Genomic Regulation]

Until now it was known that some extinct populations, such as Neanderthals or Denisovans, had mixed with modern humans outside Africa. However, in African populations no crossbreeding had been consistently demonstrated. Now, they have identified the introgression of an extinct line of humans in the DNA of present-day African populations. “This totally unknown archaic population mixed with the ancestors of Africans and their genes have been conserved in their genome until the present”, explains David Comas, full professor of Biological Anthropology at the Department of Experimental and Health Sciences (DCEXS) at UPF.

This totally unknown archaic population mixed with the ancestors of Africans and their genes have been conserved in their genome until the present.

Belén Lorente-Galdos, one of the first signatories of the article says “the scenario we know in Africa of societies that mixed in a complex way during its recent history is just the tip of the iceberg of the evolutionary history of humans, and so it would appear complex from the beginning”.

Artificial intelligence to study the DNA of African populations

The researchers have conducted a study of modern genomes of different populations with a broad diversity of lifestyles, languages or geography in the African continent. By sequencing these current genomes they have demonstrated that some of them come from introgression. “By using artificial intelligence tools and complete genomes we have been able to infer the general history of the evolution of African populations”, says Òscar Lao, principal investigator of the Population Genomics Group at the National Centre for Genome Analysis (CNAG-CRG), from the Centre for Genomic Regulation (CRG) also one of the authors of the study.

African populations crossbred with other extinct humans
The San are one of the ethnic groups that constitute the Khoisan, one of the populations studied
[Credit: Centre for Genomic Regulation]

“What has surprised us is that in order to describe the genetic diversity found in African populations today, the presence must be taken into account of an extinct archaic African population, with whom anatomically modern humans would have mixed” he adds. This result indicates that not only were there archaic populations different from the sapiens lineage outside Africa (such as Neanderthals or Denisovans), but that within this continent there were sub-populations with which anatomically modern humans who remained in Africa had offspring.

By using artificial intelligence tools and complete genomes we have been able to infer the general history of the evolution of African populations.

“This finding challenges the observations made previously on the crossbreeding of Neanderthals or Denisovans with European or Asian ancestors because Africans have always been taken as a model of population without introgression”, explains David Comas, head of the Human Genome Diversity group at the IBE. “Our research leads one to question some assumptions established today based on the premise that the African population did not have introgressions”, he adds.

Belén Lorente-Galdos concludes “our method has enabled clearly ruling out the prevalent model does that does not consider archaic introgression in Africa. The new model we present has forced us, furthermore, to review the amount of DNA in people of Eurasian origin that comes from Neanderthals, which could be up to three times higher than had been estimated to date using the previous models.”

Source: Centre for Genomic Regulation [April 26, 2019]



Early Cycladic society on Keros noted for advanced architectural planning

Four-year excavations and research on the extraordinary architectural findings of Kavos on the island of Keros in the Cycladic Islands group confirmed the existence in Early Cycladic times of a complex, stratified and technically expert society.

Early Cycladic society on Keros noted for advanced architectural planning
Credit: Hellenic Ministry of Culture and Sports

The sanctuary at Kavos on the islet of Keros was a significant regional centre for all the Cycladic Islands, the Ministry of Culture said at the conclusion of  the research programme under Cambridge University.

The programme has «revealed impressive architectural remains of a significant Early Cycladic settlement,» the ministry said.

Under the project, excavations took place on the small islet of Daskalio, originally connected to the nearby site of Kavos on Keros through a narrow strip of land. The date of Early Cycladic was confirmed scientifically, and the remains of the culture at the time include «impressive staircases, drainage pipes and stone buildings that reveal an advanced urban architecture without precedence for the specific period.»

This year’s results, the ministry said, include paths leading to the top of the settlement, passing by terraces created to support buildings. «The complicated, interlinked and multi-level architecture shows the existence of a well-organised and well-built settlement on a steep promontory,» it added.

The Daskalio buildings were mostly made of good-quality marble from Naxos island, nearly 10 km north of Keros.

Early Cycladic society on Keros noted for advanced architectural planning

Early Cycladic society on Keros noted for advanced architectural planning

Early Cycladic society on Keros noted for advanced architectural planning
Credit: Hellenic Ministry of Culture and Sports

Early Cycladic society on Keros noted for advanced architectural planning

Early Cycladic society on Keros noted for advanced architectural planning

Early Cycladic society on Keros noted for advanced architectural planning
Credit: Hellenic Ministry of Culture and Sports

According to co-excavator professor Colin Renfrew, Daskalio shows that the building techniques that were applied, the existence of huge entrance gates, stone ladders and the drainage pipes throughout the island show that there must have been a specialist architect and a central administration to carry out the building programme. He said the complexity of the construction is only comparable to Knossos on Crete for the same early period, he said.

The ministry added that materials found, including the marble and obsidian, show that the settlers were expert seamen and trade extended over a wide network reaching beyond the Cyclades.

Co-director of the site Michael Boyd added that a unique feature of the site includes the fact that metallurgy played a significant role throughout the life of the settlement. Its extent and scale proves a constant replenishing of raw materials from western Cyclades and Attica, and a social structure that trained and passed skills on to newer generations.

The fourth and last excavation period in the «Keros-Naxos Sea Roads» project took place in September and October 2018 by Cambridge University under the aegis of the British School at Athens and the supervision of the Antiquities Ephorate of the Cyclades, represented by Irene Legaki. The four-year project picked up from where the previous excavation cycle ended in 2008 at Kavos Daskaliou.

Source: Athens-Macedonian News Agency [April 26, 2019]




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