But let’s back up just a bit.
We all agree that all creatures (including dry-landers) need water in order to
live. Just how fundamental this reality is, is so major as to call
for another blog down the road. Given the abundant existence of water on
Earth, and the accompanying hydrologic cycle, which includes evaporation from
the ocean, the on-going existence of vapor in the atmosphere, the dropping of
water to the earth in the form of snow and rain, and its subsequent return to
the oceans……this cycles makes it absolutely vital to the existence of life on
Earth that our surface be constantly rearranged by plate tectonics. The constancy
of erosion from both rain and snow that makes its way back to the sea,
continues to transfer land along with it so that it too will be dumped
back into the oceans. Left alone and given enough time, all continents
are destined to level themselves out.
Were there not another cycle to
counteract the hydrologic one, we would be a water planet only (by the way I
did not happen to enjoy the movie, “Water World,” which featured Kevin
Costner). There would be no dry land masses at all. All solid mass
would everywhere be below sea level, that is, under
water! Plate tectonic counteracts this tendency by clashing land masses
together (these events are variously called “earthquakes”) to push land higher
and higher so that firstly it raises solid matter above the ocean surface
(hence dry land). And secondly, at the risk of oversimplification, it
creates mountains in two ways. By sheer force it folds sedimentary land
in on itself to form some of the most spectacular mountains in the world,
including the Andes and the Himalayas and, on our continent, the Rockies.
Plate tectonics also create land masses by volcanic processes. Wherever
the plates rub together (and other places as well) liquid magma pushes up from
the intensely hot mantle below in order to create land as well. The
Columbia Plateau which covers significant parts of the Pacific Northwest of the
United States is composed of volcanic basalt up to six thousand feet deep. The tallest mountain in the world (from bottom to
top) is not Mount Everest, but Mauna Kea, which is a part of the volcano Mauna
Loa on the “Big Island” of Hawaii. As Mauna Loa is still erupting it is
continuing to add square miles of land on out into the Pacific Ocean.
So, were it not for plate tectonics,
we earthlings would have no standing at all because there would be nothing dry
to stand on. Yet that is not the only reason for its necessity.
Scientists have stated that any planet lacking plate tectonics must be a “dead
planet” that is devoid of life. In my final blog of this series I
will add further reasons that tectonics is a requirement for the existence and
on-goingness of life on earth…and I hasten to add, that includes for
water-loving fish! Stay tuned.
One more matter. As I write
this blog today, the TV news stations are announcing a multi-ton asteroid
crashing into a city near the Ural Mountains of Russia. Just a few
minutes ago we escaped contact with another asteroid which passed us 17,000
miles above the Earth’s surface. These are potentially very destructive
events. But they are also very rare. That is because of the
existence of one of our neighboring planets. I would encourage you to
take a look at a blog relevant to this matter, titled, “Who Can’t Use a Good
Vacuum?” dated 11-27-2012.
"God
is our refuge and strength,
a
very present help in trouble.
Therefore
we will not fear though the earth should change,
though
the mountains shake in the heart of the sea."
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