I have some questions regarding the oxygen boom referred to in the last
posting...
1) presuming that glaciation was involved, could the following help explain
it?
a) glaciation would seem to be a downward spiral; that is, a lot of ice
chills the ocean currents, it chills the air, it dries the air, and snow/ice
has a high albedo -- effectively reflecting a lot of potentially warming
sunlight. You'd think that once an Ice Age starts, it would continue into
glacier lock. However...
b) glaciers are heavy; a mile thick ice sheet is so heavy that it
actually compresses the crustal rock into the mantle. Evidence is found in
Sweden, where the land is still rising after the last Ice Age (during which,
Sweden was completely covered with 1 mile of ice).
c) consider: if a mile sheet of ice covered the land, wouldn't that
weight eventually 'squirt' the underlying magma somewhere else? Thus, with
enough glaciation, eventually an automatic reverse might trigger, in that
glaciation may lead to an upwelling of volcanism, which blasts CO2 into the
atmosphere... causing a greenhouse effect, and reversing the global cooling
of the glaciation.
d) during the Pleistocene (Ice Ages) the glaciers advanced and receded
half a dozen times in 2 million years, causing all sorts of evolutionary
changes to propel forward, including our own. A glacier age may have thus
been intimately linked to the paleozoic boom, no?
-----------------------------
e) early biota are anaerobic, and poisoned by oxygen. A mutation which
could actually survive despite (and eventually because of) a massive influx
of oxygen into the air would have a huge evolutionary advantage.
------------------------------
f) here's a somewhat unrelated question: what did Dinosaurs breath?
Could the air have been thicker then, perhaps with somewhat exotic chemistry
to it? How else to explain 2' dragonflies, and 80' brachiosaurs... 'heavier'
air might explain how a 2' dragonfly still could acheive loft, and how
dinosaurs could supply enough oxygen through those tiny heads to feed such a
massive body.
Any ideas or critiques out there?
-- JHB, the gadfly
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