Subscribe free to our newsletters via your
. 24/7 Space News .

Subscribe free to our newsletters via your

How Britain became an island
By Richard INGHAM
Paris (AFP) April 4, 2017

A giant waterfall tens of kilometres (miles) wide broke down a ridge which connected modern-day England to mainland Europe nearly half a million years ago, unleashing a mega-flood that gouged out the Channel and created the island of Britain, scientists said Tuesday.

In an intricate piece of detective work, an international team of geologists said they had answered a puzzle that has gripped their profession for more than a century.

Their sleuthing focuses on an ice age some 450,000 years ago, when much of the northern hemisphere was covered by a thick glacial slab and sea levels were far lower than they are today.

The hypothetical picture of that epoch is of a Channel that was dry, cold and tundra-like.

It rose to a ridge of chalky rock that joined Britain and mainland Europe at what is now the Strait of Dover.

The scientists, writing in the journal Nature Communications, suggest that a mighty lake, fed by continental rivers, built up in the southern North Sea between the edge of the ice cap and this escarpment.

The lake started to spill over the ridge, creating a waterfall some 32 kilometres (20 miles) wide and 100 metres (330 feet) high, and disgorging into a valley far below.

The cascade eroded the crest of the dam, and eventually the wall cracked and collapsed, resulting in a tsunami that gouged out what is now the Channel.

- Geological Brexit -

The event had a huge impact on history, shaping early human settlement in Britain and the wars, trade, society and culture that followed.

"The breaching of this land bridge between Dover and Calais was undeniably one of the most important events in British history, helping to shape our island nation's identity even today," said Sanjeev Gupta of Imperial College London, who co-authored the paper.

"When the ice age ended and sea levels rose, flooding the valley floor for good, Britain lost its physical connection to the mainland," he said.

"Without this dramatic breaching, Britain would still be part of Europe. This is Brexit 1.0 -- the Brexit nobody voted for."

The idea that a glacial lake made the Channel was first aired a century ago, but struggled to make headway.

The new study, though, finds fresh evidence to back the theory. In particular, it gives the nod to a marine geologist named Alec Smith, who in 1985 suggested the mega-flood was triggered by a waterfall -- an idea that was soon forgotten.

The big clue comes from gigantic holes discovered in the bedrock of the Channel -- strange indentations up to several kilometres across and 100 metres (yards) deep, and filled with gravel and soft sand sediment.

They were found by accident in the 1960s and 1970s, when engineers drilled test holes in the sea floor as part of exploratory work for the Channel Tunnel.

In fact, the sediment was so loose that the engineers deemed that these holes were too dangerous to tunnel, and as a result the route of the Channel Tunnel was changed.

- 'Plunge pools' -

The scientists believe that these holes are so-called plunge pools -- chambers that are typically chiselled out in river beds beneath large waterfalls.

Eventually, the holes can become so big that they cause the waterfall cliff to become unstable and collapse.

Using new sonar scanning of the sea floor and a technique called seismic reflection, which uses pulses of energy to discern different rock formations, the team found that seven of these giant holes form a remarkable straight line, running from the ports of Calais to Dover -- the edge of the theorised ridge.

They also saw evidence of an ancient giant valley on the Channel floor, the signs of a massive outpouring.

The initial breach of the dam was followed by a second big event, possibly caused by a spillover of other, smaller lakes, the study suggests.

But the timeline of the two events remains unclear, and they possibly occurred hundreds of thousands of years apart.

Without this stroke of geological fate, Britain would have remained attached to the continent, rather like Denmark juts out into the sea from the European mainland, the scientists say.

Night lights, big data
Boston MA (SPX) Mar 30, 2017
When the Earth is dark, human activity sparkles across the globe. As seen from space, night-time lights tell a story about how we live, correlating to everything from electricity consumption and CO2 emissions, to gross domestic product, population and poverty. While these correlations have been studied for some time, there have been few comprehensive tools to explore these relationships at ... read more

Related Links
Earth Observation News - Suppiliers, Technology and Application

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once

credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly

paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

The long legacy of space-farming leading us to Mars

United Launch Alliance Completes Crew Emergency Egress System

Robot Fedor to Guide Russia's Federation Spacecraft in Maiden Flight - Roscosmos

Mission Control Team Finds Answers During Spacewalk

'Fuzzy' fibers can take rockets' heat

Flight Tests of Super-Heavy Angara-A5V Carrier Rocket May Start in 2027

Kremlin Believes Russia Can Compete With Private Firms Like SpaceX in Space

Russian Plant to Overhaul Nearly All Proton Rocket Engines in 2017

New MAVEN findings reveal how Mars' atmosphere was lost to space

Potential Mars Airplane Resumes Flight

Prolific Mars Orbiter Completes 50,000 Orbits

Final two ExoMars landing sites chosen

Yuanwang fleet to carry out 19 space tracking tasks in 2017

China Develops Spaceship Capable of Moon Landing

Long March-7 Y2 ready for launch of China's first cargo spacecraft

China Seeks Space Rockets Launched from Airplanes

Vietnam set to produce satellites by 2022

Globalsat Sky and Space Global sign MoU for testing and offering satellite service in Latin America

OneWeb Satellites breaks ground on high-volume satellite manufacturing facility

Start-Ups at the Final Frontier

Laser sensors spot trees with larch disease

New bioactive foam could replace lost skull bone

A self-healing, water-repellant coating that's ultra durable

Granites could solve riddle of pinpointing metals crucial for low carbon tech

TRAPPIST-1 flares threaten possibility of habitability on surrounding exoplanets

Sun's UV Light Helped Spark Life

Inventing Tools for Detecting Life Elsewhere with Future Telescopes

Viruses in the oceanic basement

Neptune's movement from the inner to the outer solar system was smooth and calm

Four unknown objects being investigated in Planet X

New Horizons Halfway from Pluto to Next Flyby Target

ANU leads public search for Planet X

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement