A couple of additional considerations:
Not all plant biomass makes it into coal. Various organisms,
including certain bacteria, protists, and fungi can consume wood, and
many others can digest less durable plant tissue such as leaves.
Lignitized wood from the Mesozoic and Cenozoic commonly is full of
holes from shipworms and other wood-boring bivalves (which have
symbiotic bacteria and protists to digest the cellulose). This also
raises the question of how long the wood had to sit exposed on the
seafloor for the shipworms to make their holes, which can raise
problems for flood geology models.
Modern driftwood does end up on the deep ocean floor, and a variety
of organisms are specialized for living on deep-sea wood. It does
not just get dispersed. The deep sea wood-borers are generally very
slow growers. Dr. Ruth Turner did extensive work on these.
A variety of coal deposits are not currently economical to mine and
may be omitted from some databases. Don't forget the Triassic rift
valley coals in the Atlantic coast states and the Cretaceous coals in
the Plains (in Canada and the U.S.) in calculating total volume.
Dr. David Campbell
Old Seashells
University of Alabama
Biodiversity & Systematics
Dept. Biological Sciences
Box 870345
Tuscaloosa, AL 35487 USA
bivalve@mail.davidson.alumlink.com
That is Uncle Joe, taken in the masonic regalia of a Grand Exalted
Periwinkle of the Mystic Order of Whelks-P.G. Wodehouse, Romance at
Droitgate Spa
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