And now this brings us to another
question, how are we going to bury organic compounds?
And it brings us to the matter of the role of tectonics of this whole affair.
Here's a map.
This is a map of all the present
day continents, not in their present position of course.
And the black areas are the areas of exposed
Archean crust.
The gray areas of exposed Proterozoic crust, and the
white areas the you know, the younger Phanerozoic crust.
That is crust that's less than about 640 billion years old.
so there's extensive Archean crust.
But what we observe is that most Archean crust is
really made of igneous rocks and metamorphic equivalents of igneous rocks.
While the Proterozoic crust, is characterized
as well by extensive sedimentary basin.
So at the end of the Archean, just
before the Great Oxygenation Event, it appears that that
was the time of the beginning of the development
of large sedimentary basins, and erosion of the continents.
So in other words this is a time also of extensive shallow seas.
Which could have been you know, provided expanded
habitat for stromatolites. the continents must have eroded at
this time, to produce all this sediment that we see in the rock record.
erosion implies that it was rock weathering,
and rock weathering implies that that, or, or
is a process rather that we expect
to influence both ocean composition, and atmosphere composition.
And the presence of the sedimentary basins is one way to
rapidly very organic material.
More generally, plate tectonics must have existed at this time.
And that also means that there was biochemical recycling,
between the surface of the planet and the mantle.
So maybe
this burial involved injection of carbon by
subduction and water by subduction into the mantle.
So all of these processes could help oxidize the Earth.