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---- Environment Q�
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Sea level
What's the deepest
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place on Earth?

Exploring the Mariana Trench, n,034ffi below sea level

he Pacific Ring of Fire is a massive area exerted on objects at these depths. In 1960, however,
around the edge of the Pacific Ocean where intrepid oceanographers Jacques Pic card and Lt Don
T most of the world's volcanic and seismic Walsh ventured to the bottom of the Mariana Trench
activity occurs. Just south of Japan, at a maximum in a bathyscaphe called the Trieste: the only
depth of n,034m, lies the deepest point on the manned submersible to reach the bottom and
surface of the planet: the Challenger Deep. return in tact. Although the men could not collect
This depression in the seabed is located at the photos, data, or samples from the seabed, their
southern end of the Mariana Trench, the geological voyage provided a new vision of what could be
product of the convergence of two tectonic plates ­ achieved in deep-sea exploration.
10 the Pacific Plate and the Mariana Plate-and a More often these days, unmanned, remotely
process called subduction whereby the larger and operated submarines and observation vessels are
denser of the two converging plates (that being used for locating, mapping, collecting and
the Pacific Plate) gets subducted under the photographing deep-sea geology and biology. In this
Earth's mantle, creating a deep depression in pitch-black world it is extremely cold and the
the Earth's crust. These trenches make up pressure of the seawater above makes for a very
the deepest parts of the world's oceans ­ inhospitable environment for marine life let alone
and for this reason such areas remain eager explorers. However, each new dive seems to
practically uncharted. uncover another species of aquatic life in this
Less than five per cent of the world's unique underwater ecosystem and with new
oceans have been explored due to the developments in submersible vehicles we are
inaccessible nature of deep sea (the drawing ever closer to uncovering more of this, the
lowest layer in the ocean) and the unfathomable deep. Right now, we've only
massive pressure (some 16,ooopsi) scratched the surface. 0

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