Brexit

About half a million years ago, in the midst of an Ice Age, a land bridge connected Dover in the South of England to Calais in northern France.

Immediately to the north of it, was a huge glacial lake, which had formed at the edge of the ice sheet that covered much of Europe.

When it started to overflow, vast amounts of water crashed over the land bridge, forming a series of very large waterfalls.

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The lake overflowed 450,000 years ago, damaging the land link. Then a later flood fully opened the Dover Strait.

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The scars of these events have recently been found on the seabed of the English Channel. The study is published in the journal Nature Communications by S. Gupta et al. on 04 April 2017.

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Decades ago, engineers who were surveying the seabed for the Channel Tunnel, discovered a series of mysterious large underwater holes (fosse) between Dover and Calais, caused by the lake overspill (black regions on the map above)  The fosse are now in-filled with sediment and show up as a line of isolated depressions 100m-deep carved into the bedrock and hundreds of metres to several kilometres in diameter.

450,000 years ago, the glacial lake water plunged over the rock ridge as a series of waterfalls from Dover to Calais, which then eroded and carved out these depressions.

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A second catastrophic flood took place about 150,000 years ago forming a huge valley about 10km wide with a lot of features suggesting flood erosion. Perhaps an ice sheet broke off, collapsing into the lake, causing a surge that carved a path for the water to cascade off the chalk ridge. As the channel floor slowly eroded by these torrential floods, seawater from the Atlantic Ocean rushed into the resulting channel, isolating the British Isles from the mainland.

 

Dark Age

An article by S Guillet et al in this month’s Nature Geoscience relates an interval of global climate cooling to the Samalas volcanic eruption in 1257.

The Indonesian island of Lombok remains from that eruption:

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In Europe that year, text and illustrations from the Annals of Speyer record the bad weather and harvest. Grapes and other fruit were unavailable. The dark winter was even given a proper name by peasants: the munkeliar –

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There was smoke and heavy cloud elsewhere and it is now thought that the event may have triggered the Little Ice Age starting in the early fourteenth century:300px-2000_Year_Temperature_Comparison.png

Black Sea Treasure

Archaeologists have found more than 40 vessels in the Black Sea, some more than a millennium old, shedding light on early empires and trade routes.

00SHIPWRECKS4-superJumbo.jpgWJ. Broad reported in the NY Times, Nov 11th 2016, that one medieval ship lay more than a half-mile down at the bottom of the Black Sea, offshore Bulgaria. The masts, timbers and planking have been undisturbed for seven or eight centuries. Lack of oxygen in the icy depths had prevented bacteria and fungi attacking the wet wood.

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Last month a team of explorers lowered a robot on a long tether, lit up the wreck with bright lights and took thousands of high-resolution photos. A computer then merged the images into a detailed portrait.

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Archaeologists date the discovery to the 13th or 14th century when the ship probably served the Venetian empire, which had many Aegean and Black Sea outposts.

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Never before had this type of ship been found in such complete form. The breakthrough was the quarterdeck, from which the captain would have directed a crew of perhaps 20 sailors.

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The Voynich Manuscript

In a book edited by R Clemens, Yale University Press have recently published a new summary of this mysterious document (see go.nature.com/2dlns1c).

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Radiocarbon dating shows the original manuscript is from between 1404 and 1438. Of course, there is a possibility that the parchment version may be a forgery.

Wilfrid Voynich, who died in 1930, bought the manuscript from a Jesuit archive in Italy, then took it to London and then to New York.

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The origin remains unknown, and the meaning of its strange alphabetic calligraphy is still uncoded. The illustrations are of bathing women, dubiously recognisable plants and maps of stars.

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Peopling Asia

Scientists are correlating the genetic features of different races with their territory. Many of the genetical groups have restricted locations.

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The patches of strong colour in the map represent distinct genetic features, based on human genome data. They follow familiar geographic features such as mountain ranges, sea barriers and deserts.

In Asia, the migration routes have been recognised for some time.

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(See Nature October 13. 2016: Genomic analyses inform on migration events during the peopling of Eurasia – by Luca Pagani et al)

Europe in tatters at Pompeii

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What’s the point of loving Pompeii if we let it fall?

The ancient Roman city preserved in ash by an eruption of Mount Vesuvius in AD79 has never been more popular. The Neoclassical imitations and fashion for “Pompeiian red” that its beautiful art inspired when Pompeii first captured imaginations in the 18th century were enjoyed by an elite.

 

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Now, large areas of Pompeii are closed off to visitors, behind ugly wire fences put up by a Neapolitan construction company after a series of collapses due to heavy rains in 2013 and 2014 caused worldwide consternation.

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An emergency restoration project, funded by the EU and Italy, got under way to put right seeming years of neglect. Now it looks like a project that is scarring Pompeii as much as saving it. The fences have been slapped up carelessly looking like an urban building site.

Sinking Delta

In 500BC, Canopus and Thonis-Heracleion were Egyptian cities of the Nile delta whose ports traded with Greece. Between then and 800AD the cities sank for reasons as yet unknown. Maybe the cities’ enormous sculptures were toppled by a catastrophic earthquake (known to have occurred in 796AD). Or maybe the clay soils underlying the cities became saturated and couldn’t support the enormous weight of the statues.

About twenty years ago the submerged monuments were recovered by divers and now form an exhibition at the British Museum, which is open until 27th November.

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Above: Stela, commissioned by Nectanebo I, 380 BC. Photo: Christoph Gerigk. © Franck Goddio/Hilti Foundation.

sunken_cities_3.jpg    Left:  Hapy, an ancient Egyptian god.

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Above: A pink granite garden vat. Thonis-Heracleion, Egypt, Ptolemaic Period, 4th–2nd century BC. Photo: Christoph Gerigk. © Franck Goddio/Hilti Foundation.

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Above: a diver shows a marble statue of Osiris. Canopus, Egypt, 1st–2nd century AD. Photo: Christoph Gerigk. © Franck Goddio/Hilti Foundation

The sculptures show that Egypt was not the insular self-centred country that some historians have believed. The ports of the delta were busy gateways to European cities not so very far away.