Missing -- a huge chunk of the earth's crust
Pastor Dale Morgan
Missing -- a huge chunk of the earth's crust*
05 Mar 2007 16:23:51 GMT
Source: Reuters
By Stefano Ambrogi
LONDON, March 5 (Reuters) - A team of British scientists set sail on
Monday to examine why a huge chunk of the earth's crust is missing, deep
under the Atlantic Ocean -- a phenomenon that challenges conventional
ideas about how the earth works.
The 20-strong team aims to survey an area some 3,000 to 4,000 metres
(9,840 to 13,120 feet) deep where the mantle -- the deep interior of the
earth normally covered by a crust kilometres thick -- is exposed on the
sea floor.
Experts describe the hole along the mid-Atlantic ridge as an "open
wound" on the ocean floor that has puzzled scientists for the five or so
years that its existence has been known because it defies existing
tectonic plate theories of evolution.
"We know so little about it," said Bramley Murton, a senior research
scientist at Southampton's National Oceanography Centre.
"It's a real challenge to our established understanding of what the
earth's surface looks like underneath the waves," he told Reuters by
telephone from the brand new, hi-tech British research ship RRS James Cook.
Mid-ocean ridges are places where new oceanic crust is born, with
red-hot lava spewing out along the seafloor.
What scientists are keen to know is whether the crust was ripped away by
huge geological faults, or whether it never even developed in the first
place.
The primary motivation for the project was to understand how the earth
continues to evolve.
"The area that we are looking at is part of a mountain range that spans
thousands of square kilometres, but we are beginning to realise that
there are probably millions of square kilometres where the ocean floor
is missing," Murton said.
The six-week mission, led by geophysicist Roger Searle of Durham
University and Chris MacLeod of Cardiff University's School of Earth,
Ocean and Planetary Sciences, will recover sample cores of rock by
drilling into the mantle using a rig lowered on to the sea floor.
Asked if the discovery posed a threat to the environment, Murton
replied: "It's not problematic for the earth because it is a natural
earth process -- but in terms of knowing how the earth works and how the
world is put together it is important."
Murton also said the expedition would shed light on the composition of
sea water amongst other initiatives.
Crust formation is a fundamental mechanism of the earth which affects
the chemistry of the world's oceans.
Progress by the research team can be monitored via a live web link to
the ship at: http://www.noc.soton.ac.uk/gg/classroom@sea/JC007/.