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Latest archaeology news, archaeological discoveries from across the globe
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Paleolithic diet of snails 10,000 years earlier than previously thought

Wed, 2014-08-20 18:29
Paleolithic inhabitants of modern-day Spain may have eaten snails 10,000 years earlier than their Mediterranean neighbors, according to a study published August 20, 2014 in the open-access journal PLOS ONE.

Snails were widespread in the Late Pleistocene and Holocene, but it is still unknown when and how they were incorporated into human diets. The authors of this study found land snail shell remains from ~30,000 years ago at a recently discovered site in Cova de la Barriada, Spain.

To better understand if the inhabitants may have eaten snails, the researchers investigated patterns of land snail selection, consumption, and accumulation at the site, and then analyzed the shells’ decay, fossilization process, composition, and age at death by measuring the shell size.

Scientists found groupings of complete shells from a large land snail species at three areas of the site, corresponding to different time points ~30,000 years ago.

The adult snails were close to prehistoric human-constructed structures that may have been used to cook the snails, along with stone tools, and other animal remains that were likely roasted in ambers of pine and juniper at 375 C.

The authors posit that these results point to previously undiscovered patterns of invertebrate use and may highlight a broadening of the human diet in the Upper Paleolithic in the Mediterranean basin. In neighboring Mediterranean areas, eating land snails didn’t appear until about 10,000 years later, which may make these newly found snail shells the oldest known evidence that ancient human populations used them as a food resource in Europe ~30,000 years ago.

PLOS

 

Categories: General

Rome’s first emperor died 2000 years ago – his tomb is now used as a toilet

Wed, 2014-08-20 12:09
Augustus, who died 2000 years ago, was the first emperor of Rome. He brought peace after the turmoil in the republic after the assassination of Julius Caesar when he defeated the forces of Antony and Cleopatra.

But despite this, two millenia after he bestrode the world, his mausoleum lies in disrepair under piles of rubbish while his celebrated stables, only discovered five years ago, are to be reburied due to lack of funds.

The mausoleum of Augustus – WikiPedia

There’s a rich agenda of special and extravagant events in Rome as it celebrates the 2000th anniversary of the death of Augustus. The city is packed with cultural events, from special exhibitions to the re-enactment of ancient Roman rites. But the restoration of these important monuments are a step too far – one that simply can’t be afforded.

The mausoleum of Augustus is the monument that should be a star of the celebrations. Their restoration works, which are part of a larger project that aims to convert the square surrounding the monument into a pedestrian area, began in 2006, but have been interrupted for years. The work was a project of the local government and the negligence of the city council appears to be the cause of the progressive degradation of the area. Rubbish piled up against the pillars of the portico and eventually the restoration site became first a toilet and then a shelter for a group of homeless people.

These inhabitants of Augustus’s burial place converted the fences into clothes hangers and one of them even built a shop for his artworks. Since this spring the situation improved as the square has been partially cleaned; but the mausoleum is still closed to visitors. There are hopes for its reopening at the end of 2014, but I’m certainly not holding my breath.

And then there are Augustus’s fabled stables, discovered during the construction of a new underground car park in the heart of Rome. The plan was to have them open to visitors by the time of the current celebrations, but now they are to be reburied due to lack of funding.

Their discovery in 2009 was deemed an extremely important archaeological find, making for a unique opportunity to study the structure of the stables in the Roman era and the organisation of the games held in the Circus Maximus. But despite the value of this project, the efforts of the society in charge of the excavations have the tragic futility of Sisyphus’ curse.

Circus Maximus : WikiPedia

Five years of work and €5m are to be buried under a thick layer of “pozzolana”, a material made of volcanic ash. The stables will be left to rest there, protected from erosion, until new funds become available – perhaps for the rediscovery of future generations. The car park will be built, but its new location has yet to be decided upon.

There are no public funds for such restorations and there are unlikely to be. But Ialy’s minister of cultural heritage, Dario Franceschini, has been inviting foreign investors to help the country to preserve its artistic and historical beauties. The minister told the New York Times:

Our doors are wide open for all the philanthropists and donors who want to tie their name to an Italian monument … We have a long list, as our heritage offers endless options, from small countryside churches to the Colosseum … Just pick.

Italian luxury shoe brand Tod’s was certainly happy to finance the restoration of the Coliseum – gaining copyrights and incomparible visibility along the way. And Fendi didn’t miss the opportunity to sponsor the Trevi Fountain, where beauty and fashion icon Anita Ekberg took a bath in Fellini’s La Dolce Vita.

But the recently discovered and less famous stables did not attract local or foreign sponsors. Despite its historical importance, the site is not so appealing to corporate brands who look for prestige and visibility in such ventures. The stables require a massive investment of time and money, they cannot be open to visitors before the completion of a long process of excavation and restoration – and they won’t make for a good film location anytime soon.

Worryingly, the growing power of the corporate sector in arts and heritage funding very possibly may bring a serious change in our conception of cultural heritage – from majestic symbols of our past, to expensive advertising gimmicks.

And so the bimillenary of Augustus takes us on a bizarre tour from car parks to cardboard boxes. As we celebrate Rome’s past grandeur we find the Divus Augustus’s tomb covered in not very divine garbage, and consign an archaeological gem to rest under the streets. Until, perhaps, a mega fashion brand from the future decides to dig it up for some fabulous campaign or other.

Written by Alice Borchi

CC – The Conversation

Categories: General

Evolution of marine crocodilians constrained by ocean temperatures

Wed, 2014-08-20 09:40
The ancestors of today’s crocodiles colonized the seas during warm phases and became extinct during cold phases, according to a new Anglo-French study, which establishes the link between marine crocodilian diversity and the evolution of sea temperature over a period of over 140 million years.

The research, led by Jeremy Martin from the Université de Lyon, France and formerly form the University of Bristol, UK will be published this week in Nature Communications.

Today, crocodiles are ‘cold-blooded’ animals that usually reside in fresh water but with two notable exceptions, Crocodylus porosus and Crocodylus acutus occasionally venture into the sea. Crocodiles reside in tropical climates, and they are frequently used as markers of warm conditions when they are found as fossils.

Large Crocogylus Porosus: Wikimedia

Only 23 species of crocodiles exist today but once there were hundreds of species. On four occasions in the past 200 million years, major crocodiles groups entered the seas and proceeded to become extinct. It remains a mystery why they made these moves, and equally why they all eventually went extinct. This new study implies that crocodiles repeatedly colonized the oceans at times of global warming.

Lead author of the report, Dr. Jeremy Martin said: “We thought each of these evolutionary events might have had a different cause. However, there seems to be a common pattern.”

Dr. Martin, accompanied by a team of palaeontologists and geochemists from the Université de Lyon and the University of Bristol, compared the evolution of the number of marine crocodilian fossil species to the sea temperature curve during the past 200 million years. This temperature curve, established using an isotopic thermometer, is widely applied for reconstruction of past environmental condition and in this case, is based on the isotopic composition of the oxygen contained in the fossilized remains of fossil marine fish (bone, teeth, scales).

Co-author of the study, Christophe Lécuyer explained: “According to this method, it is possible to calculate the temperature of the water in which these fish lived by applying an equation linking the isotopic composition of the fossilized remains to the temperature of mineralization of their skeleton. The seawater temperatures derived from the composition of fish skeleton thus corresponds to the temperature of water in which the marine crocodiles also lived.”

The results display that colonization of the marine environment about 180 million years ago was accompanied by a period of global warming of the oceans. These first marine crocodilians became extinct approximately 25 million years later, during a period of global freezing. Then, another crocodilian lineage appeared and colonized the marine environment during another period of global warming.

The evolution of marine crocodilians is therefore closely linked to the temperature of their medium and provides information about their evolution and lifestyle, as in modern crocodilians, is constrained by environmental temperatures.

Nevertheless, one fossil lineage does not seem to follow this trend. Jurassic metriorhynchoids did not go extinct during the cold spells of the early Cretaceous, unlike the teleosaurids, another group of marine crocodilians. Surprisingly, metriorhynchoids only disappeared a few million years later. This exception will certainly provide new grounds for novel research, particularly into how the biology of this group adapted to life in the pelagic environment.

Professor Michael Benton from the University of Bristol, who also co-authored the study, said: “This work illustrates a case of the impact of climate change on the evolution of animal biodiversity, and shows that for crocodilians, warming phases of our earth’s history constitute ideal opportunities to colonise new environments.”

 

 

Contributing Source: University of Bristol

Header Image Source: WikiPedia

Categories: General

£1.5 million aid for historic buildings

Tue, 2014-08-19 13:50
More than £1.5 million has been awarded to help repair seven historic buildings across Scotland as part of Historic Scotland’s Building Repairs Grants scheme.

The announcement was made by the Cabinet Secretary for Culture and External Affairs, Fiona Hyslop, whilst on a visit to Hospitalfield House in Arbroath, which had itself been awarded £500,000 as part of the scheme.

Hospitalfields House: Wikimedia

Ms Hyslop said: “We are incredible lucky in Scotland to have a built heritage which is the envy of the world. By investing in these important buildings we are not just ensuring the protection of these vital, tangible connections to our past but also ensuring that they play a prominent role in the future of their communities.

“Hospitalfield is a great example of a site which has served a range of purposes throughout its long and distinguished history and now, thanks to the support of Historic Scotland, Creative Scotland, and others, a new chapter in its history can be opened. I’m sure that Hospitalfield will serve as a cultural hub for the people of Angus for many years to come.”

The house has its origins as a medieval hospital, serving pilgrims visiting Arbroath Abbey. By 1813, when Walter Scott visited and was inspired to write his book The Antiquary, the house was part of the country estate of the Fraser family. Only thirty years later, artist Patrick Allan married the heir to the estate, Elizabeth Fraser, and the couple set out to remodel the house – a project that took over 70 years.

They created the wonderful interiors, vast Picture Gallery, and accumulated the important Victorian collections of painting, sculpture and furniture.  In 1890 Patrick Allan-Fraser died leaving the house and estate for the support of artists. it was here that painters such as James Cowie, Joan Eardley, Ian Fleming, Robert Colquhoun and Robert McBryde spent time working. Latterly, many art students from the four main Scottish Art Schools have benefited from use of the building.

The legacy of the Allan-Fraser’s will live on as Hospitalfield upgrades its facilities to support the artists of the 21st century. It will continue to be a place for artists to develop and make new work but also to increasingly welcome visitors to enjoy the unique site and the programmes. The house and gardens will be open to the public on  6 & 7 September for Open Doors Day.

The Building Repair Grants Scheme exists to give financial aid to owners of buildings of special architectural or historical interest, in order to meet the cost of high-quality repairs, using traditional materials and specialist craftsmen, to conserve original features.

The recipients of grant funding in this round are:

  • Campbeltown Town Hall, Argyll and Bute £264,480  – 18th Century distinctive example of civic pride expressed through its architecture
  • Hospitalfield House, Angus £500,000 – With its origins as a medieval hospital, Hospitalfield became the 19th Century Scottish Baronial vision of artist Patrick Allan-Fraser and his wife Elizabeth
  • Aberdeen Music Hall,   £222,062 built in the early 19th Century, it is a prime example of Aberdeen’s monumental granite classicism. Still plays host over 5,000 events every year.
  • Castle of Mey, Caithness £193,440  – A listed, 16th Century building best known for its association with the Royal Family
  • The Haining House, Selkirkshire £371,260– comprises of a group of nationally important A-listed buildings, built in 1795 in the classical style
  • Craig Castle, Aberdeenshire, £13,598 – Castellated courtyard mansion, associated with the great Gordon family of Aberdeenshire
  • Hans Hamilton Tomb, East Ayrshire £7,490– rare example of 17th Century funerary architecture

 

Contributing Source: Historic Scotland

Header Image Source: WikiPedia

Categories: General

500 million year reset for the immune system

Tue, 2014-08-19 09:46
A single factor has the potential to reset the immune system of mice to a state similar to what it was 500 million years ago, a time when the first vertebrates emerged.

Scientists at the Max Planck Institute of Immunobiology and Epigenetics (MPI-IE) in Freiburg re-activated the expression of an ancient gene, which is not usually expressed in the mammalian immune system, and discovered that these animals developed a fish-like thymus. To the researchers astonishment, while the mammalian thymus is utilised exclusively for T cell maturation, the reset thymus produced not only T cells, but also served as a maturation site for B cells – a property normally seen in the thymus of fish alone. Therefore, the model potentially could provide a new insight of how the immune system had developed in the course of evolution. The study has been published in Cell Reports.

The adaptive immune response is unique to vertebrates. One of its core organs is the thymus, which is present in all vertebrate species. Epithelial cells in the thymus control the maturation of T cells, which later fight degenerated or infected body cells. The gene FOXN1 is in charge of the development of such T cells in the mammalian thymus. Scientists led by Thomas Boehm, director at the MPI-IE and head of the department for developmental immunology, activated the evolutionary ancestor of FOXN1, called FOXN4, in the thymic epithelial cells of mice. FOXN4 is present in all vertebrates, but appears to play only a role in the maturation of immune cells of jawed fish, such as cat sharks and zebra fish.

“The simultanuous expression of FOXN4 and FOXN1 in the mouse led to a thymus that showed properties as in fish,” said first author Jeremy Swann. Coupled with earlier results this implies that the development function of thymic tissue was originally initiated by FOXN4. Due to an evolutionary gene duplication, which led to FOXN1, transiently both genes, and finally only FOXN1 were active in the thymus.

To the surprise of the research team, not only T-cells developed in the thymus of mice, but also B-cells. Mature B-cells are responsible for antibody production. In mammals, they usually do not mature in the thymus, but in other organs, such as the bone marrow.

“Our studies suggest a plausible scenario for the transition of a bipotent lymphopoietic tissue to a lymphoid organ supporting primarily T cell development,” said Boehm. Since B- and T-cell progenitors cannot yet be distinguished, it remains unclear whether the B-cell development is based on the migration of dedicated B-cell precursors to the thymus, or to maturation from a shared T/B progenitor in the thymus itself. Comparative studies often suggest that the origin of a particular evolutionary innovation must have occurred in an extinct species. “Here, the re-creation and functional analysis of presumed ancestral stages could provide essential insights into the course of such developments,” explained Boehm the study approach.

 

 

Contributing Source: Max-Planck-Gesellschaft

Header Image Source: WikiPedia

Categories: General

Toothless ‘dragon’ pterosaurs dominated the Late Cretaceous skies

Mon, 2014-08-18 15:44
A new study provides an exciting insight into the Late Cretaceous and the diversity and distribution of the toothless ‘dragon’ pterosaurs from the Azhdarchidae family. The research was published in the open access journal ZooKeys.

The Azhdarchidan pterosaurs are named from the Persian word for dragon- Aždarha. Fascinatingly, this derived a rather successful group of pterosaurs, which included some of the largest known flying animals of all time, with wingspans reaching between 10 and 12 meters.

‘Dragon’ pterosaurs once had a worldwide distribution and were the last of their kind to inhabit the planet, until approximately 60 million years ago. They dominated the skies during the Late Cretaceus and unlike their predecessors, were characteristically toothless.

“This shift in dominance from toothed to toothless pterodactyloids apparently reflects some fundamental changes in Cretaceous ecosystems, which we still poorly understand,” comments the author of the study Dr Alexander Averianov, Zoological Institute of the Russian Academy of Sciences.

Pterodactylus fossil: WikiPedia

Generally fossil record of pterosaurs is patchy and confined mostly to sedimentary deposits known as Konservat-Lagerstätten where exceptional depositional conditions facilitated preservation of fragile pterosaur bones. Unfortunately, such Lagerstätten are extremely rare for the Late Cretaceous when the majority of the evolutionary history of Azhdarchidae took place, which makes these exciting creatures incredibly difficult to study.

“Azhdarchidae currently represent a real nightmare for paleontologists: most taxa are known from few fragmentary bones, which often do not overlap between named taxa, the few articulated skeletons are poorly preserved, and some of the best available material has remained undescribed for forty years.” explains Dr Averianov about the difficulties studying the group.

Despite these difficulties, the number of localities where azhdarchidan ptersosaurs were discovered is impressive and reflects the important role they played in the Cretaceous ecosystems. These flying giants likely inhabited a vast variety of environments, but appear to have been abundant near large lakes and rivers and most common in a nearshore marine environment.

 

 

 

Contributing Source: Pensoft Publishers

Header Image Source: WikiPedia

Categories: General

New home for an ‘evolutionary misfit’

Mon, 2014-08-18 12:32
A worm-like creature with legs and spikes finally finds its place in the evolutionary tree of life.

One of the most bizarre-looking fossils ever discovered- a worm-like creature with legs, spikes and a head difficult to distinguish from its tail- has found its place in the evolutionary Tree of Life, definitively linking it with a group of modern animals for the first time.

The animal, known as Hallucigenia due to its otherworldly appearance, had been considered an’ evolutionary misfit’ because it was not clear how it was related to modern animal groups. Researchers from the University of Cambridge have discovered a crucial link with modern velvet worms, also known as onychophorans, a relatively small group of worm-like animals that reside in tropical forests. The results have been published in the advance online edition of the journal Nature.

The affinity of Hallucigenia and other contemporary ‘legged worms’, collectively known as lobopodians, has been very controversial, due to the lack of clear characteristics linking them to each other or to modern animals It has been difficult to determine their evolutionary home.

Also, early interpretations of Hallucigenia, which was first identified in the 1970s, placed it both backwards and upside-down. Originally, the spines along the creature’s back were thought to be legs and the legs were thought to be tentacles along its back, and its head was mistaken for its tail.

Hallucigenia resided about 505 million years ago during the Cambrian Explosion, a period of rapid evolution when the most major animal groups first appeared in the fossil record. These particular fossils come from the Burgess Shale in Canada’s Rocky Mountains, one of the richest Cambrian fossil deposits in the world.

Looking like something from science fiction, Hallucigenia had a row of rigid spines along its back, and seven or eight pairs of legs ending in claws. The animals were between 5 and 35 millimeters in length, and lived on the floor of the Cambrian oceans.

Hallucigenia Fossil: WikiPedia

A novel study of the creature’s claws unveiled an organisation very close to those of modern velvet worms, where layers of cuticle (a hard substance similar to fingernails) are stacked on inside the other, like Russian nesting dolls. The same nesting structure can also be seen in the jaws of velvet worms, which are no more than legs modified for chewing.

“It’s often thought that modern animal groups arose fully formed during the Cambrian Explosion,” said Dr Martin Smith of the University’s Department of Earth Sciences, the paper’s lead author. “But evolution is a gradual process: today’s complex anatomies emerged step by step, one feature at a time. By deciphering ‘in-between’ fossils like Hallucigenia, we can determine how different animal groups built up their modern body plans.”

While Hallucigenia was a suspected ancestor of the velvet worms, its definitive characteristics linking them together had been hard to find, and their claws had never been studied in detail. Through analysing both the prehistoric and living creatures, the researchers discovered that claws were the connection joining the two animals together. Cambrian fossils continue to produce new information and origins of complex animals, and the use of high-end imaging techniques and data on living organisms further allows researchers to untangle the enigmatic evolution of earliest creatures.

“An exciting outcome of this study is that it turns our current understanding of the evolutionary tree of arthropods – the group including spiders, insects and crustaceans – upside down,” said Dr Javier Ortega-Hernandez, the paper’s co-author. “Most gene-based studies suggest that arthropods and velvet worms are closely related to each other; however, our results indicate that arthropods are actually closer to water bears, or tardigrades, a group of hardy microscopic animals best known for being able to survive the vacuum of space and sub-zero temperatures – leaving velvet worms as distant cousins.

“The peculiar claws of Hallucigenia are a smoking gun that solve a long and heated debate in evolutionary biology, and may even help to decipher other problematic Cambrian critters,” said Dr Smith.

 

 

Contributing Source: University of Cambridge

Header Image Source: WikiPedia

Categories: General

Bone Chemistry reveals royal lifestyle of Richard III

Mon, 2014-08-18 09:31
A new study conducted by the British Geological Survey, in association with researchers at the University of Leicester, has explored the bone and tooth chemistry of King Richard III and unveiled fascinating new details about the life and diet of Britain’s last Plantagenet King. The study, published in Elsevier’s Journal of Archaeological Science indicated a change in diet and location in his early childhood, and in later life, a diet comprising of expensive, high status food and drink. This forensic study, the most complete study to have been conducted on a medieval monarch, has been featured in a documentary, Richard III: The New Evidence, which aired on Channel 4 on Sunday 17th August at 9pm.

Isotope analysis of bone and tooth material from King Richard III has revealed new details of his early life and the change in his diet when he became king two years and two months before his death at the Battle of Bosworth. The research examines the changes in chemistry found in the teeth, the femur and the rib; all of which develop and rebuild at different stages of life.

Isotope measurements that relate to geographical location, pollution and diet (strontium, nitrogen, oxygen, carbon and lead) were analysed in three locations on the skeleton of Richard III. The teeth, which form in childhood, confirmed that Richard had relocated from Fotheringay castle in eastern England by the age of seven. The data suggests that during this time he was in an area of higher rainfall, older rocks and with a changed diet relative to his birthplace of Northamptonshire. Through examination of the femur, which represents an average of the 15 years before his death, researchers showed that Richard moved back to eastern England as an adolescent or young adult, and had a diet that matched the highest aristocracy.

The third location, the rib, renews itself fairly quickly, so it only represents between 2 and 5 years of life before his death. Data from the isotopes in this bone indicate the greatest change in diet. Although an alteration in the chemistry between the femur and the rib of Richard III could indicate relocation, historical records display that Richard did not relocate from the east of England prior to his death when he was King. As such, this chemical change is more likely to represent a change in diet relating to his period as King. The difference implies an increase in the consumption of freshwater fish and birds, which were popular additions to royal banquets at the time and included birds such as swan, crane, heron and egret. As well as this, the bone chemistry suggests his consumption of wine increased during his short rein and reinforces the notion that food and drink were strongly linked to social status in Medieval England.

Memorial to King Richard III: WikiPedia

Dr Angela Lamb, Isotope Geochemist and lead author of the paper says, “The chemistry of Richard III’s teeth and bones reveal changes in his geographical movements, diet and social status throughout his life.”

Richard Buckley from the University of Leicester Archaeological Services and lead archaeologist in the Richard III dig, said, “This cutting edge research has provided a unique opportunity to shed new light on the diet and environment of a major historical figure –Richard III. It is very rare indeed in archaeology to be able to identify a named individual with precise dates and a documented life. This has enabled the stable-isotope analysis to show how his environment changed at different times in his life and, perhaps most significantly, identified marked changes in his diet when he became king in 1483.”

The Dig for Richard III was led by the University of Leicester, working alongside Leicester City Council and in association with the Richard III Society. The originator of the Search project was Philippa Langley of the Richard III Society.

 

Contributing Source: Elsevier

Header Image Source: Wikimedia

Categories: General

Luas Works Reveal Multiple Human Remains at College Green

Fri, 2014-08-15 19:34
During Luas Cross City works on College Green, monitoring archaeologists from Rubicon Heritage Services Ltd, working on behalf of the Railway Procurement Agency made a discovery of human remains.

The skull of one of the individuals excavated at College Green (Copyright: Rubicon Heritage Services Ltd

The archaeological team located an individual at a depth of 1.5m below the present ground surface, immediately north of the gates of Trinity College, Dublin. The individual was situated below the known level of post-medieval activity, suggesting the remains are most likely medieval or earlier in date.

Over the course of subsequent days the partial remains of at least four more individuals were uncovered within the trench; these were archaeologically excavated from the area in July. This suggests that this part of College Green functioned as a cemetery at some point in Dublin’s past.

Rubicon Heritage Site Director Nikolah Gilligan, who led the excavation, noted that ‘all bar one of the individuals were positioned in north-south orientated grave cuts, apparently with no grave goods present.’ Gilligan added that ‘it is too early to confirm the date of the human remains, though the possibility that they are Viking cannot be discounted, given previously recorded Viking activity in the area.’

Rubicon Human Remains Specialist Carmelita Troy has carried out a visual assessment of the remains, confirming that at least one of the individuals was an adult male, while one of the others was a sub-adult, aged under 18 years at the time of their death.

The Project Archaeologists from the Railway Procurement Agency will oversee detailed environmental and osteoarchaeological analysis of the remains to be undertaken by Rubicon Heritage Services, which is now set to take place. This will reveal significantly more information about the lives and deaths of these individuals and the city in which they lived.

Rubicon Heritage Services – Header Image : One of the individuals under excavation at College Green (Copyright: Rubicon Heritage Services Ltd)

One of the individuals under excavation at College Green (Copyright: Rubicon Heritage Services Ltd) – See more at: http://www.rubiconheritage.com/2014/08/14/press-release-luas-works-reveal-multiple-human-remains-college-green/#sthash.D2wGa2TR.dpuf
Categories: General

Scientists to explore how insects evolved ultrasonic hearing abilities over millennia

Fri, 2014-08-15 19:00
A grant of £250,000 from The Leverhulme Trust has been awarded to a team of scientists led by the University of Lincoln, UK, to study how a group of insects evolved incredible ultrasonic hearing abilities.

A cochlear organ for frequency selectivity was thought to be unique to hearing in mammals until a similar mechanism for frequency analysis was found in the ears of bushcrickets in South American rainforests two years ago.

Scientists believe the discovery of this previously unidentified hearing organ could pave the way for technological advancements in bio-inspired acoustic sensors, including medical imaging devices and hearing aids.

The new research project, funded by The Leverhulme Trust, aims to develop an integrated understanding of the evolution of ultrasonic hearing in bushcrickets; specifically how they developed cochlear-like systems in response to changing evolutionary pressures over millions of years.

Samples of fossil material. (A, B) Preserved wings and stridulatory structures. (C) Fossilised ear on the leg, with clear presence of tympanal structures.

Project lead Dr Fernando Montealegre-Z, from the School of Life Sciences, University of Lincoln, UK, led the team who discovered the previously unidentified hearing organ in bushcrickets.

He explained: “We will study these hearing systems and their variation in many species of bushcrickets. There are around 7,000 living species of these insects, but what we know about cochlear mechanisms has been investigated in only two or three. Therefore we expect to find enormous amount of variation across species. Through data from fossils and existing species, we aim to unveil major changes in sensory ecological niches and in the auditory ecology of species which have evolved from a single ancestral species.”

Bushcrickets are among the first terrestrial animals to have evolved acoustic communication. The sound emitted by crickets is produced by the stridulatory organ, a large vein running along the bottom of one wing, covered with “teeth”, which is rubbed against a plectrum on the other wing. The ears, located on their forelegs, are used in mating and predator avoidance.

Nearly 70 per cent of the living species, measured with ultrasound-sensitive equipment, produce acoustic signals in the ultrasonic range. However, their ancestors communicated at much lower frequencies. Modern bushcrickets emerged some 55-60 million years ago. Since bats arose at about the same time, the group hypothesise that bushcrickets might have evolved ultrasonic communication and elaborate hearing organs in response to acoustic predators, such as echolocating bats.

For the first time, the group will reconstruct changes in shape and function of fossil bushcrickets’ auditory and stridulatory organs throughout the recorded history of this group, from the Triassic onwards. This will enable them to understand the selective pressures that drove the evolution of cochlear systems in mammals and insects.

The work will enable the construction of a series of biophysical models that will simulate and predict tympanal vibrations and wing resonances in extinct bushcrickets, plus the acoustic reconstruction of the bushcricket community that lived in the long-gone forests of the Triassic and Jurassic eras.

Dr Montealegre-Z said: “Findings will help to comprehend the multiple origins and diversity of auditory mechanisms in mammals and insects. Results will also open up our understanding of the acoustic ecology of extinct environments where other auditory animals lived, and not only provide insights into the lives of singing insects, but that of their prey and predators. Studying fossil insects advances our general understanding of both behavioural and physical ecologies of the forests of the distant past.

“The research encompasses several disciplines including paleontology, biophysics, physiology and engineering. The integration of these disciplines is original and innovative and will open up new opportunities to enhance the current knowledge of sensory mechanisms in living organisms, including humans.”

Categories: General

The Mummy’s Face: Solving an Ancient Mystery

Thu, 2014-08-14 14:18
He looks almost Byzantine or Greek, gazing doe-eyed over the viewer’s left shoulder, his mouth forming a slight pout, like a star-struck lover or perhaps a fan of the races witnessing his favorite charioteer losing control of his horses.

In reality, he’s the “Bearded Man, 170-180 A.D.,” a Roman-Egyptian whose portrait adorned the sarcophagus sheltering his mummified remains. But the details of who he was and what he was thinking have been lost to time.

But perhaps not for much longer. A microscopic sliver of painted wood could hold the keys to unraveling the first part of this centuries-old mystery. Figuring out what kind of pigment was used (whether it was a natural matter or a synthetic pigment mixed to custom specifications), and the exact materials used to create it, could help scientists unlock his identity.

“Understanding the pigment means better understanding of the provenance of the individual” said Darryl Butt, a Boise State distinguished professor in the Department of Materials Science and Engineering and associate director of the Center for Advanced Energy Studies (CAES). “Where the pigment came from may connect it to a specific area and maybe even a family.”

For years, researchers were limited by the lack of samples large enough to be properly analyzed. But advances in the field of nanotechnology mean scientists now can work with fragments tinier than the eye can even register. Using a $1.5 million ion beam microscope at CAES, Butt — along with CAES colleagues Yaqaio Wu and Jatu Burns, and Boise State student researchers Gordon Alanko and Jennifer Watkins — is working with a sliver of the wood portrait smaller than a human hair.

The team transferred the fragment to a sample holder using a tiny deer hair called an “eyelash.” Their biggest challenge was to move it to the equipment without losing it.

So far they have extracted five needle-tip sized fragments 20 nanometers wide (a nanometer is a billionth of a meter), as well as two thin foils. From that, they have been able to analyze and map out the chemistry of the material in three dimensions.

“So far we’ve learned that the paint is a synthetic pigment,” said Butt, who as an artist in his own right often mixes his own pigments for his paintings. “These are very vibrant pigments, possibly heated in a lead crucible. People thought that process had been developed in the 1800s or so. This could prove it happened a lot earlier.”

Butt and his team are analyzing a speck of purple paint, which is significant because the blue used to blend the purple hue was a precious pigment back in the day, signaling a prominent individual.

“Bearded Man, 170-180 A.D.” from the Walters Art Museum – WikiPedia

Their data is being analyzed by researchers from the Detroit Museum of Art, where a companion to the “Bearded Man” mummy resides. It’s part of a project, titled APPEAR (Ancient Panel Paintings-Examination, Analysis, Research), a collaboration between 12 museums, including the British Museum in London and the Walters Art Museum in Baltimore, Maryland.

Butt got into solving art mysteries when he met Glenn Gates, a conservation scientist at the Walters Art Museum at a conference at Stanford University. Both are officers of a new section of the American Ceramic Society — the Art, Archaeology and Conservation Science division.

“This research was a gamble that we [materials scientists] could do some really cool stuff,” Butt said, noting that he would love to branch out into analyzing pottery and other ancient artifacts.

While studying the provenance of Roman Egyptian mummies is something new at Boise State, many researchers in the art, geology, history, anthropology and even English departments are involved in what Butt likes to call ‘reverse engineering’ of objects of cultural heritage.

“This particular problem, that is of understanding a particle of pigment from a 2,000-year-old sarcophagus, is a bit unique in that it highlights some of the amazing tools that we have at Boise State and at CAES that could shed new light on problems associated with understanding human history,” he said.

Butt hopes that these and similar transdisciplinary projects will open up external research opportunities for students, including creation of a “pipeline” of students who travel to various user facilities or museums to carry out interdisciplinary research.

“Envision, for example, art students studying works of art using synchrotron radiation and bright x-rays at a national laboratory, while science and engineering students use their technical skills to unravel mysteries of materials used by ancient societies in the field or held by museums,” he said.

The idea can sound far-fetched even for those who are participating in the research, although there is a certain, sound logic to transdisciplinary work between the arts and the sciences.

“I never anticipated having an opportunity to work on a project like this as an undergraduate research assistant in an engineering discipline,” said Watkins, who is a junior majoring in materials science and engineering. “I’ve enjoyed being able to interact with other departments on campus and experience other facets of research that I otherwise would not have been exposed to. I think there is a very interesting niche for materials characterization in archaeological research.”

“The key to creating these external opportunities or internships for students requires that we develop a reputation as well as students with the right skills and mindset for this kind of work,” Butt said. “That’s what we’re doing now.”

Boise State University

Categories: General

Embalming study ‘rewrites’ key chapter in Egyptian history

Wed, 2014-08-13 22:53
Researchers from the Universities of York, Macquarie and Oxford have discovered new evidence to suggest that the origins of mummification started in ancient Egypt 1,500 years earlier than previously thought.

The scientific findings of an 11-year study by a researcher in the Department of Archaeology at York, and York’s BioArCh facility, and an Egyptologist from the Department of Ancient History at Macquarie University, push back the origins of a central and vital facet of ancient Egyptian culture by over a millennium.

Traditional theories on ancient Egyptian mummification suggest that in prehistory — the Late Neolithic and Predynastic periods between c. 4500 and 3100 B.C. — bodies were desiccated naturally through the action of the hot, dry desert sand.

Scientific evidence for the early use of resins in artificial mummification has, until now, been limited to isolated occurrences during the late Old Kingdom (c. 2200 BC). Their use became more apparent during the Middle Kingdom (c. 2000-1600 BC).

But the York, Macquarie and Oxford team identified the presence of complex embalming agents in linen wrappings from bodies in securely provenanced tombs in one of the earliest recorded ancient Egyptian cemeteries at Mostagedda, in the region of Upper Egypt.

“For over a decade I have been intrigued by early and cryptic reports of the methods of wrapping bodies at the Neolithic cemeteries at Badari and Mostagedda,” said Dr Jana Jones of Macquarie University, Sydney.

“In 2002, I examined samples of funerary textiles from these sites that had been sent to various museums in the United Kingdom through the 1930s from Egypt. Microscopic analysis with my colleague Mr Ron Oldfield revealed resins were likely to have been used, but I wasn’t able to confirm my theories, or their full significance, without tapping into my York colleague’s unique knowledge of ancient organic compounds.”

Dr Jones initiated the research and led the study jointly with Dr Stephen Buckley, a Research Fellow at the University of York.

“Such controversial inferences challenge traditional beliefs on the beginnings of mummification,” said Dr Jones. “They could only be proven conclusively through biochemical analysis, which Dr Buckley agreed to undertake after a number of aborted attempts by others. His knowledge includes many organic compounds present in an archaeological context, yet which are often not in the literature or mass spectra libraries.”

Corresponding author on the article, Dr Buckley, used a combination of gas chromatography-mass spectrometry and sequential thermal desorption/pyrolysis to identify a pine resin, an aromatic plant extract, a plant gum/sugar, a natural petroleum source, and a plant oil/animal fat in the funerary wrappings.

Predating the earliest scientific evidence by more than a millennium, these embalming agents constitute complex, processed recipes of the same natural products, in similar proportions, as those employed at the zenith of Pharaonic mummification some 3,000 years later.

Dr Buckley, who designed the experimental research and conducted the chemical analyses, said: “The antibacterial properties of some of these ingredients and the localised soft-tissue preservation that they would have afforded lead us to conclude that these represent the very beginnings of experimentation that would evolve into the mummification practice of the Pharaonic period.”

Dr Buckley added: “Having previously led research on embalming agents employed in mummification during Egypt’s Pharaonic period it was notable that the relative abundances of the constituents are typical of those used in mummification throughout much of ancient Egypt’s 3000 year Pharaonic history. Moreover, these resinous recipes applied to the prehistoric linen wrapped bodies contained antibacterial agents, used in the same proportions employed by the Egyptian embalmers when their skill was at its peak, some 2500-3000 years later.”

Professor Thomas Higham, who was responsible for dating the burials at the University of Oxford, said: “This work demonstrates the huge potential of material in museum collections to allow researchers to unearth new information about the archaeological past. Using modern scientific tools our work has helped to illuminate a key aspect of the early history of ancient Egypt.”

“Our ground-breaking results show just what can be achieved through interdisciplinary collaboration between the sciences and the humanities,” said Dr Jones.

University of York – Header Image : WikiPedia

Categories: General

Mind-Blowing Giant Crystals — What Can They Teach Us?

Tue, 2014-08-12 16:16
Giant gypsum crystals — some of which are in excess of 30 feet long and half a million years old — are found deep within the Naica mine in Chihuahua, Mexico and are renowned for their spectacular beauty.

While large gypsum crystals can also be found at sites around the world, such as Segóbriga and Pulpí in Spain, and the El Teniente mine in Chile, Naica boasts the most exceptional ones.

But the beauty of these crystals isn’t entirely on their outside. Tiny gases trapped inside the crystals are revealing secrets about crystal growth and morphology under conditions difficult to replicate within a laboratory because of the amount of time required to grow crystals of that enormous size.

The lessons of these giant, ancient crystals will be explored at the International Union of Crystallography (IUCr) Congress and General Assembly meeting next week in Montreal, Canada. There, Juan Manuel García-Ruiz, a researcher and professor for Spain’s National Research Council at the University of Grenada, as well as the founder and director of the Laboratory for Crystallographic Studies, will describe how they are formed and what they are teaching us.

“In Naica, several geologic conditions have been fulfilled to form the giant crystals — including the existence of two minerals with reverse solubility vs. temperature, a hot point, and very slow cooling for thousands of years,” says.

In Montreal, García-Ruiz will present a plenary lecture entitled “From the Crystal to the Rose: The Route to Biomimetic Self-assembled Nanostructured Materials,” a movie “The Mystery of the Giant Crystals,” and a poster exhibition about the role of crystals in our everyday life.

García-Ruiz first became interested in giant crystals years ago while focusing on obtaining tiny crystals of proteins — a cornerstone technique in modern biology that scientists use to solve the structures of molecules relevant to human health and disease. At that time in his life, growing a crystal of proteins only a few hundred microns equated to a big success.

Then he received an invitation to study the formation of large gypsum crystals in Segobriga, Spain, which had been described during Roman times by Pliny the Elder as “lapis specularis.” He was hooked. “These crystals were the precursors of what we now call glass windows. It’s a fascinating story that explains the terminology confusion surrounding the words ‘crystal’ and ‘glass’ in some languages,” García-Ruiz said.

In the movie “The Mystery of the Giant Crystals,” García-Ruiz travels with documentary filmmaker Javier Trueba to four different caves where these spectacular examples of the mineral world have been found and explores how they were formed.

The film will be shown at 5:35 p.m. on August 7, 2014 in Room 517bc of the the Palais des congrès de Montréal. García-Ruiz will also give a lecture on crystals for the public at 8:15 p.m. on August 6, 2014 in room Leacock 132 on the McGill University Campus.

Origins of Life on Earth

Another topic García-Ruiz will discuss in Montreal is his own research looking at how mineral self-organization can provide answers to big questions about primitive life detection and the origins of life on Earth.

“For many years, it was believed that living organisms and crystalline minerals belonged to two separate worlds of symmetry, because life is able to create complex shapes with continuous curvature that were considered impossible as the product of mineral precipitation,” he explained.

So morphology has traditionally been used as a tool for biogenesis when searching for the oldest remnants of life on the planet or elsewhere — can we find evidence, in other words, of ancient biological molecules based on the morphology of shapes seen in the fossil record.

“We’ve demonstrated, however, that under similar conditions to the primitive earth, silica interacts with carbonates to form complex self-assembled purely inorganic structures with shapes that are indistinguishable from those considered to be remnants of the oldest life on Earth,” García-Ruiz said.

“This means that morphology alone can’t be used as the sole criterion for biogenecity,” he added. “We need to develop new analytical tools to reveal when life appears in this planet and if whether or not there is life elsewhere.”

This finding made García-Ruiz question whether silica can perform a similar role to the one played by organic matter in biomineralization. He’s currently exploring whether this ability of silica to trigger self-organization may have played a catalytic role in the formation of organic molecules from inorganic minerals and even triggered chemical reactions that lead to complex organic molecules.

Categories: General

Climate change and drought in ancient times

Tue, 2014-08-12 15:55
The influence of climate on agriculture is believed to be a key factor in the rise and fall of societies in the Ancient Near East. Dr. Simone Riehl of Tübingen University’s Institute for Archaeological Science and the Senckenberg Center for Human Evolution and Palaeoenvironment has headed an investigation into archaeological finds of grain in order to find out what influence climate had on agriculture in early farming societies.

Her findings are published in this week’s PNAS – Proceedings of the National Academy of Sciences.

She and her team analyzed grains of barley up to 12,000 years old from 33 locations across the Fertile Crescent to ascertain if they had had enough water while growing and ripening. Riehl found that periods of drought had had noticeable and widely differing effects on agriculture and societies in the Ancient Near East, with settlements finding a variety of ways to deal with the problem.

The 1,037 ancient samples were between 12,000 and 2,500 years old. They were compared with modern samples from 13 locations in the former Fertile Crescent. Dr. Riehl and her team measured the grains’ content of two stable carbon isotopes. When barley grass gets insufficient water while growing, the proportion of heavier carbon isotopes deposited in its cells will be higher than normal. The two isotopes 12C und 13C remain stable for thousands of years and can be measured precisely – giving Simone Riehl and her colleagues reliable information on the availability of water while the plants were growing.

They found that many settlements were affected by drought linked to major climate fluctuations. “Geographic factors and technologies introduced by humans played a big role and influenced societies’ options for development as well as their particular ways of dealing with drought,” says Riehl. Her findings indicate that harvests in coastal regions of the northern Levant were little affected by drought; but further inland, drought lead to the need for irrigation or, in extreme cases, abandonment of the settlement.

The findings give archaeologists clues as to how early agricultural societies dealt with climate fluctuations and differing local environments. “They can also help evaluate current conditions in regions with a high risk of crop failures,” Riehl adds. The study is part of a German Research Foundation-backed project looking into the conditions under which Ancient Near Eastern societies rose and fell.

Universitaet Tübingen – Header Image : WikiPedia

Categories: General

Space-age technologies aim to uncover Britain’s heritage

Tue, 2014-08-12 15:48
A team from the University of Leicester is to investigate the potential use of UAV (Unmanned Aerial Vehicle) technology to advance understanding of our heritage.

Using novel ground penetrating radar techniques from the platform of a UAV the researchers hope to investigate previously inaccessible sites to better understand how people have been using space and creating places over time.

The project has come about thanks to a new partnership between the University of Leicester and Loughborough based Sterling Geo through the part European Regional Development Fund (ERDF) funded ‘Innovation through the Research Support Accelerator’ (IRSA) Project.

Sterling Geo is part-funding the appointment of a new M.Phil. research student, Mark Collins, who is  tasked with looking into novel ways of using unmanned aerial vehicles.

By partnering up, Sterling Geo is able to benefit from the experience and knowledge of the Geography, Archaeology and Geophysics disciplines at the University of Leicester and the IRSA project. Their academic knowledge and experience helps to support the development of ideas currently in an embryonic state.

Under the supervision of Professor Heiko Balzter and Dr Booker Ogutu of the Department of Geography, Mark will shortly begin investigating solutions utilising lightweight GPR units and UAV platforms. Mark graduated from the University of Leicester with a BA in Archaeology in the School of Archaeology and Ancient History.

Mark said: “My interests particularly lie in researching prehistoric landscapes in order to better understand how people have been using space and creating places over time.

“New technologies and techniques, like the GPR, that can potentially be used to investigate previously inaccessible sites are an exciting development that I’m pleased to be involved with.”

Mark has access to several testing grounds, including the site of a Roman villa that the Department of Archaeology & Ancient History are currently working on and an area of extensive peat bog-land of interest to the Geography Department.

He said: “I’m really excited to be part of a project that combines new applications of technology and geographic science in a way that has obvious implications for my own research.

“I’d like to say thank you to everyone at Sterling Geo, the University of Leicester, G-STEP and the IRSA Programme for giving me the opportunity to research it.”

Teresa Smith, IRSA’s ERDF Project Manager and Education Specialist, said: “IRSA is delighted to be supporting 12 months’ dedicated research in collaboration with Sterling Geo in the fast developing area of UAVs and their associated instrumentation.

“This is exactly the sort of project the IRSA and ERDF is interested in funding to further strengthen regional links between the University of Leicester and the East Midlands body of innovative companies.”

Ed Lamb of the University of Leicester’s G-STEP project, which assisted with project organisation, sees great benefit in the work. He said: “We see UAVs being used more frequently and in a broader range of applications in the future so there is need for research now.

“The G-STEP project mission is to assist East Midlands based SMEs with access to earth observation data and GIS and the successful start of the project strengthens ties with Sterling Geo and is of great benefit to both the company and university as it links industry with world class research.”

Phil Cooper, Director and General Manager for Sterling Geo, said: “We are committed to supporting academic research in the field of Geographical and Environmental Science.  We currently offer huge discounts on ERDAS software to academic organisations through the CHEST agreement and now we’re pleased to be able to cover Mark’s university fees to enable this essential research.

“We already have strong links with the University of Leicester. I studied there myself and our employee Emily Winter graduated there last year. I’m proud to be able to provide the opportunity for someone else to succeed.”

University of Leicester and Sterling Geo will be publishing updates on the progress of the M.Phil throughout the year.

Contributing Source : University of Leicester

Categories: General

Reconstructions show how some of the earliest animals lived…and died

Tue, 2014-08-12 11:57
New three-dimensional reconstructions display how some of the world’s earliest animals developed, and offer some answers as to why they went extinct.

A strange group of uniquely shaped organisms known as rangeomorphs may have been some of the earliest animals to appear on Earth, they were uniquely suited to ocean conditions 575 million years ago. A new model created by researchers at the University of Cambridge has resolved many of mysteries around the structure, evolution and extinction of these ‘proto animals’. The findings are reported today in the journal PNAS.

Rangeomorphs were among the earliest large organisms to grace the Earth, existing during a period where most other forms of life were microscopic in size. Most rangeomorphs were approximately 10 centimeters high, although some managed to grow to a height of two meters.

These animals were ocean dwellers and lived during the Ediacaran period, between 635 and 541 million years ago. Their bodies comprised of soft branches, each with many smaller side branches, forming a geometric shape known as a fractal, which can be seen as many familiar branching shapes such as fern leaves and even river networks.

Rangemorphs were unlike any modern organism seen today, which has made it difficult to determine how they completed tasks such as feeding, growing or reproducing. This has therefore made it difficult to link them to any particular modern group. However, despite the fact that they looked like plants, evidence suggests that rangeomorphs were actually some of the earliest animals.

Rangeomorph: WikiPedia

“We know that rangeomorphs lived too deep in the ocean for them to get their energy through photosynthesis as plants do,” said Dr. Jennifer Hoyal Cuthill of Cambridge’s Department of Earth Sciences, who led the research. “It’s more likely that they absorbed nutrients directly from the sea water through the surface of their body. It would be difficult in the modern world for such large animals to survive only on dissolved nutrients.”

“The oceans during the Ediacaran period were more like a weak soup – full of nutrients such as organic carbon, whereas today suspended food particles are swiftly harvested by a myriad of animals,” said co-author Professor Simon Conway Morris.

Starting 541 million years ago, the conditions in the oceans with the start of the Cambrian Explosion – a period of rapid evolution when most major animal groups first emerge in the fossil record and competition for nutrients increased dramatically.

Rangeomorphs have often been considered a ‘failed experiment’ of evolution as they died out so quickly after the Cambrian Explosion began in earnest, but this new analysis shows how successful they once were.

Rangeomorphs almost completely filled the space surrounding them, with a large total surface area. This enabled them to be very efficient feeders with the ability to extract the maximum amount of nutrients from the ocean water.

“These creatures were remarkably well-adapted to their environment, as the oceans at the time were high in nutrients and low in competition,” said Dr Hoyal Cuthill. “Mathematically speaking, they filled their space in a nearly perfect way.”

Dr. Hoyal Cuthill examined rangeomorph fossils from a number of locations across the world, and used them to make the very first computer reconstructions of the development and three-dimensional structure of these organisms, showing how they were actually well-suited to their Ediacaran environment.

As the Cambrian Explosion began however, the rangeomorphs became ‘sitting ducks’, as they had no defensive features to protect them from predators, which were beginning to evolve, and the changing chemical composition of the ocean meant that they could no longer get the nutrients they required to feed.

“As the Cambrian began, these Ediacaran specialists could no longer survive, and nothing quite like them has been seen again,” said Dr Hoyal Cuthill.

 

 

Contributing Source: University of Cambridge

Header Image Source: WikiPedia

 

 

Categories: General

Western Wall Wearing Away? Discovery of Extreme Erosion Process Could Guide New Preservation Techniques

Mon, 2014-08-11 11:16
Researchers from the Hebrew University of Jerusalem investigated erosion in the different types of limestone in the Western Wall located at the foot of Jerusalem’s Temple Mount. Stones comprised of large crystals were almost unchanged in 2000 years, while limestone containing small crystals eroded much faster and in some cases had receded by tens of centimeters, potentially weakening the wall’s structure. The researchers describe an accelerated erosion process that explains why some rocks are more weathered than others, and displayed that chemo-mechanical erosion extends down to the tiny micron scale. The findings could have significant implications for regional and global carbonate weathering, and could help guide the development of effective preservation techniques that slow the rate of erosion in order to protect cultural heritage sites around the world.

Visitors to the Western Wall in Jerusalem can see that some of its stones have suffered extreme erosion. This is good news for people placing prayer notes in the wall’s many cracks and crevices, but presents a major problem for engineers concerned about the structure’s stability.

The Western Wall is a remnant of the ancient wall that surrounded the courtyard of the Jewish Temple in Jerusalem. It resides in Jerusalem’s Old City at the foot of the Temple Mount.

Part of the Western Wall showing highly eroded blocks alongside well preserved stones. (Photo: Dr. Simon Emmanuel, Hebrew University)

In order to calculate the erosion in the different kinds of limestone that make up the Western Wall, researchers from the Hebrew University of Jerusalem used a laser scanner to create an accurate three-dimensional computer model. The researchers are Dr. Simon Emmanuel, the Harry P. Kaufmann Senior Lecturer in Environmental Water Technology, and PhD student Mrs. Yael Levenson, at the Hebrew University’s Institute of Earth Sciences.

As reported in an article accepted for publication in the journal Geology, they discovered that stones comprised of large crystals were resistant to wear, so they remained in a good condition over the 2000 years since they were put into place. However, limestone with very small crystals (about a thousandth of a millimeter in size) eroded at a much faster rate.

Microscope image of Jerusalem limestone made up of tiny crystals. (Photo: Dr. Simon Emmanuel, Hebrew University)

In some cases, extreme erosion rates in fine-grained micritic limestone blocks were up to 100 times faster than the average rates estimated for the coarse-grained limestone blocks. In some places these stones had receded by tens of centimeters, potentially weakening the entire structure.

In order to obtain a better understanding of what causes the two types of rock to behave differently, the researchers collected samples from ancient quarries thought to have supplied the stones for the Second Temple. Using a powerful atomic force microscope, they were able to see how the rocks disintegrated when they came into contact with water. During the experiments on rocks comprised of small crystals, tiny particles rapidly detached from the surface of the rock. These experiments stimulated the way in which rainwater interacts with limestone in nature.

Observed for the first time in Dr. Emmanuel’s lab, this process of accelerated erosion has the potential to explain why some rocks are more weathered than others. While mechanical weathering is thought to act on blocks and chips of rock at the visible outcrop sale, the researchers displayed for the first time that chemo-mechanical erosion extends down to the tiny micron sale. The findings could have significant implications for regional and global carbonate weathering.

According to Dr. Emmanuel, “Understanding such weathering processes could help guide the development of effective preservation techniques. For example, it may be possible to develop materials that slow the rate of erosion by binding the tiny crystals in the rock together. Advanced engineering techniques like this should assist efforts to protect not only the Western Wall, but other cultural heritage sites in Israel and around the world.”

The research appears as “Carbonate weathering rates accelerated by micron-scale grain detachment,” in the journal Geology. The research was supported by the Israel Science Foundation.

 

 

Contributing Source: Hebrew University of Jerusalem

Header Image Source: Wikimedia

Categories: General

Ancient shellfish remains rewrite 10,000-year history of El Niño cycles

Mon, 2014-08-11 10:16
The planet’s largest and most powerful driver of climate changes from one year to the next, the El Niño Southern Oscillation in the tropical Pacific Ocean, was believed to have been weaker in ancient times due to the different configuration of the Earth’s orbit. However, scientists analyzing 25-foot high piles of ancient shells have uncovered new information that has led them to believe that the El Niños 10,000 years ago were just as strong and frequent as the ones that we still experience today.

The findings, from the University of Washington and University of Montpellier, question the accuracy of computer models in reproducing historical El Niño cycles, or predict how they could alter under future climates. The paper can now be accessed online and will appear in an upcoming issue of Science.

“We thought we understood what influences the El Niño mode of climate variation, and we’ve been able to show that we actually don’t understand it very well,” said Julian Sachs, a UW professor of oceanography.

El Niño: WikiPedia

The ancient shellfish feasts also upend a widely held interpretation of past climate.

“Our data contradicts the hypothesis that El Niño activity was very reduced 10,000 years ago, and then slowly increased since then,” said first author Matthieu Carré, who conducted the research as a UW postdoctoral researcher and now holds a faculty position at the University of Montpellier, France.

Back in 2007, while at the UW-based Joint Institute for the Study of the Atmosphere and Ocean, Carré accompanied a group of archaeologists to seven coastal sites in Peru. Together they sampled 25-foot high piles of shells from Mesodesma donacium clams eaten and then discarded over centuries into piles that archaeologists have named middens.

While attending graduate school, Carré developed a technique to analyze shell layers to obtain ocean temperatures, using carbon dating of charcoal from fires to get the year, and the ratio of oxygen isotopes in the growth layers to get the water temperatures as the shell was forming.

The shells offer 1-to-3-year-long records of monthly temperatures of the Pacific Ocean along Peru’s coastline. Combining layers of shells from each site gives water temperatures for intervals spanning from 100 to 1,000 years during the past 10,000 years.

The new records show that 10,000 years ago the El Niño cycles were strong, contradicting the current leading interpretations. Approximately 7,000 years ago the shells show a shift to the central Pacific of the most severe El Niño impacts, followed by a lull in the strength and occurrence of El Niño from around 6,000 to 4,000 years ago.

A possible explanation for the surprising finding of a strong El Niño 10,000 years ago was that another factor was compensating for the dampening effect expected from cyclical changes in Earth’s orbit around the sun during that period.

“The best candidate is the polar ice sheet, which was melting at a substantial rate in this period and may have increased El Niño activity by changing ocean currents,” Carré said.

Approximately 6,000 years ago the majority of the ice age floes would have finished melting, therefore the effect of the Earth’s orbital geometry may have taken over to enable the period of weak El Niños.

In previous studies, warm-water shells and evidence of flooding in Andean lakes had been interpreted as signs of a much weaker El Niño approximately 10,000 years ago.

According to Carré this novel data is more reliable, for three reasons: the Peruvian coast is strongly affected by El Niño; the shells record ocean temperature, which is the most important parameter for the El Niño cycle; and the ability to record seasonal changes, the timescale at which El Niño can be observed.

“Climate models and a variety of datasets had concluded that El Niños were essentially nonexistent, did not occur, before 6,000 to 8,000 years ago,” Sachs said. “Our results very clearly show that this is not the case, and suggest that current understanding of the El Niño system is incomplete.”

The US National Science Foundation, the US National Oceanic and Atmospheric Administration and the French National Research Agency funded the research.

Other co-authors of the paper are Sara Purca at the Marine Institute of Pero; Andrew Schauer, a UW research scientist in Earth and space sciences, Pascale Braconnot at France’s Climate and Environmental Sciences Laboratory, Rommel Angeles Falcón at Peru’s Minister of Culture; and Michèle julien and Danièle Lavallèe at Frances’s Renè Ginouvès Institute for Archaeology and Anthropology.

 

Contributing Source: University of Washington

Header Image Source: Wikimedia

 

Categories: General