BIVALVES

Y13 don't forget your prep on Bivalves & Brachiopods!

LOST CONTINENT FOUND BY RADIOMATRIC DATING

A lost continent which sank millions of years ago has been found at the bottom of the Indian Ocean.

Named Mauritia by scientists, it is believed to have existed intact up to 85million years ago.

Part of this small microcontinent is still above water, and is now part of the Seychelles, a group of islands between Madagascar and India.

The discovery was made after sand from the beaches of Mauritius was analysed and found to be hundreds of millions of years older than expected.

The grains contained zircon minerals up to 1.9billion years old that may have formed part of the ancient land of Rodinia.

They were dragged 10km (6.2 miles) up to the surface after a volcanic eruption 9million years ago.

Zircon is something you typically find in a continental crust – they are very old in age.’

India drifted from Madagascar causing the microcontinent to break up and disappear into the sea. However, some of the land has survived.

‘At the moment, the Seychelles is a piece of granite, or continental crust, sitting practically in the middle of the Indian Ocean,’ Prof Torsvik, told the journal Nature Geoscience.

‘But once upon a time it was sitting north of Madagascar.

‘What we are saying is maybe this was much bigger. There are many of these continental fragments spread around in the ocean.’

GEOLOGY SOUVENIRS cont'd

The Crinoid Necklace.

Photo: Douglas Branch

WORLD'S WEIRDEST VOLCANO

In Geography today I mentioned some weird lavas in Africa at the Oldoinyo Lengai volcano. 
Do watch the Youtube clip, it is weird!!

https://www.youtube.com/watch?v=qputaVyn7TE

Most volcanologists would agree that the answer to that question is Ol Doinyo Lengai, a volcano in northern Tanzania. From a distance, this handsome volcano doesn't look unusual. The symmetrical cone rises 2,200 m (7,200 ft) above the baking plains of the East African Rift Valley.

During the last century, activity at Ol Doinyo Lengai has been concentrated in its summit crater, which is currently about 400 m across. Because of its remote location, few scientists made the arduous trek to the crater until the last few decades. Those who reach the crater are usually rewarded with the sight of spatter cones, small lava flows, and sometimes lava lakes and low lava fountains. Lava flows have gradually filled the crater, and, in the last two years, thin flows have regularly overflowed the crater rim and descended a short way down the cone.

Intestinal Lava flow

The record that Ol Doinyo Lengai holds is that it is the only volcano in the world known to have erupted carbonatite lava in historical time. Because of its very unusual composition, carbonatite is literally the coolest lava on earth, erupting at 500-600 degrees Centigrade, compared with 1,160 degrees C  for lava from Kilauea's current eruption.

An active carbonatite flow is black or brown and reminds many eyewitnesses of runny mud. Only at night do carbonatite flows glow a dull orange or red.

Freshly cooled flows in the crater of Ol Doinyo Lengai are black but soon turn white because of chemical reactions that occur as the lava absorbs water. In rainy weather, this color change can occur before the flows are cold. Within a few months of erupting, lava flows turn into a brown powder due to water absorption.

What makes this lava so different from the stuff we're used to? The chemical composition of carbonatite magma includes very little silica (silicon dioxide), the most abundant chemical constituent of the earth's crust.

Carbonatite magma at Ol Doinyo Lengai has less than 3% silica and is more akin to something you'd expect to find on a different planet. Cooled carbonatite lava is composed mainly of carbonate minerals. 

NOW FORGET THIS INFORMATION, IT IS NOT ON THE A LEVEL SYLLABUS!!

EARTH SCIENCE PICTURE OF THE DAY

Every day a new photograph of a spectacular feauture is uploaded. 

Trawl through the archive to see some beautiful Earth images. 

You can even send in your own photo and hope it will appear on the website.

http://epod.usra.edu/blog/

DEEPEST BLACK SMOKERS DISCOVERED

UK scientists exploring the ocean floor in the Caribbean have discovered an "astounding" set of hydrothermal vents, the deepest anywhere in the world.

Deploying a remotely-operated vehicle (ROV) in the Cayman Trough, they stumbled across a previously-unknown site nearly 5000m below the surface. Video pictures relayed live back to the research ship mounting the operation show spindly chimneys up to 10m high.

http://www.bbc.co.uk/news/science-environment-21520404

WHAT IS EVOLUTION? DARWIN'S BRILLIANT IDEA- VIDEO

http://www.guardian.co.uk/science/video/2013/jan/25/evolution-masterclass-darwin-video

Biology teacher Ceri Evans gives a masterclass to students on what he says is arguably the greatest idea anybody ever had: evolution. He uses a series of activities to demonstrate genetic variation, mutation, competition, survival of the fittest, niches and adaptation through natural selection. He also introduces the students to the originator of that great idea, Charles Darwin

ASTEROID NEAR MISS (FRIDAY 15TH FEB)

'Record close' asteroid may miss the Earth but it could take out your phone.

Scientists have dismissed fears an asteroid due to whizz past the Earth on Friday will 'destroy London' - but it could take out vital telecommunications satellites.

Scientists say they are sure there is no chance of the 150ft (45.7m) wide space rock hitting the planet.

But there is a remote possibility that it could collide with one of more than 100 telecommunication and weather satellites in fixed orbits above the Earth.

The asteroid, 2012 DA14, has been closely tracked since its discovery a year ago.

It is predicted to reach its nearest point to the Earth at around 7.30pm UK time on Friday.

Experts have calculated it will stay at least 17,200 miles (27,681km) away - easily far enough to be safe, but a very close shave in astronomical terms. Scientists have never observed such a narrow miss before.

http://www.telegraph.co.uk/science/space/9860421/Record-close-asteroid-may-miss-the-Earth-but-it-could-take-out-your-phone.html

METEORITE HITS BOY

A schoolboy has survived a direct hit by a meteorite after it fell to earth at 30,000mph. 

Gerrit Blank, 14, was on his way to school when he saw "ball of light" heading straight towards him from the sky. A red hot, pea-sized piece of rock then hit his hand before bouncing off and causing a foot wide crater in the ground.

The teenager survived the strike, the chances of which are just 1 in a million - but with a nasty three-inch long scar on his hand. He said: "At first I just saw a large ball of light, and then I suddenly felt a pain in my hand.

"Then a split second after that there was an enormous bang like a crash of thunder." "The noise that came after the flash of light was so loud that my ears were ringing for hours afterwards.

"When it hit me it knocked me flying and then was still going fast enough to bury itself into the road," he explained.

Scientists are now studying the pea-sized meteorite which crashed to Earth in Essen, Germany.

"Most don't actually make it to ground level because they evaporate in the atmosphere. Of those that do get through, about six out of every seven of them land in water," he added.

The only other known example of a human being surviving a meteor strike happened in Alabama, USA, in November 1954 when a grapefruit-sized fragment crashed through the roof of a house, bounced off furniture and landed on a sleeping woman.

SUPERVOLCANO THREAT: 'MANTLE PLUMES'

Life on Earth could be at threat from a catastrophic "supervolcano" which seismologists believe is due to erupt – in 200 million years' time.

At least two "piles" of rock the size of continents are crashing together as they shift at the bottom of Earth's mantle, 1,800 miles (2,900km) beneath the Pacific Ocean.

In doing so they are creating a well of partially molten rock the size of Florida, raising the prospect of a rare eruption of disastrous proportions, seismologists claim.

But the danger is "not imminent" and is likely to occur between 100 million and 200 million years from now if at all, the team from the University of Utah added.

The piles of rock were initially discovered in the 1990s, lying just above the Earth's core below some of Earth's most active volcanic zones in the South Pacific and Africa.

But a new study using earthquake waves to generate images of the Earth's interior, in a similar way that X-rays are used on the human body, found that the piles are crashing into one another.

Dr Michael Thorne, who led the study, said: "What we may be detecting is the start of one of these large eruptive events that – if it ever happens – could cause very massive destruction on Earth.

"This is the type of mechanism that may generate massive plume eruptions, but on the timescale of 100 million to 200 million years from now. So don't cancel your cruises."

The first, a hotspot plume supervolcano eruption, could be of similar scale to three eruptions at Yellowstone in the US over the past two million years, which covered much of North America with ash.

Alternatively it could result in flood basalt eruptions which could bury entire regions under igneous rock.

The scientists detected the movement of the plates using data on 51 earthquakes which took place deep below the Earth's surface, examining changes in waves to detect variations in the rock sitting above the core.

Using computer simulators, they were able to determine the shape and size of the two piles, and identify "blobs" of semi-molten rock on their edges.

Dr Thorne said: "My study might be the first to show actual seismic evidence that the piles are moving. People who have done previous simulations have suggested this.

"They are sitting atop the core and getting pushed around by overlying mantle forces like subduction. They move around on the core somewhat like continental plates drift at Earth's surface."

HUMAN ANCESTORS

Click on the Google Doodle (sorry not hyperlinked) to find out more about Mary Leakey.

She discovered some of the oldest human skulls (in the Olduvai Gorge, Tanzania) and nearby the 3.5 million year old footprints of human ancestors at Laetoli. 

Do you remember the story? Two sets of adult footprints, female walking in the footprints of the male, with child sized footprints alongside as if they were holding hands. 
All preserved in wet volcanic ash.
For more information: 
http://www.pbs.org/wgbh/aso/tryit/evolution/footprints.html

HALF TERM GEOLOGY PHOTOS

Going anywhere at half term? Take a photo of something of geological interest! 

Send it to WCS geology HQ, and it may be included in the blog!

It could be at the coast, up a mountain, on the Mendips 

or even in a city centre (e.g. gneiss at Cribbs Causeway) 

LARGEST ICEBERG CALVING EVER FILMED

Watch the Youtube video (4mins) right through to see the amazing calving event in context.

Thanks to Mr Tapner for the link

http://www.youtube.com/embed/hC3VTgIPoGU?rel=0