Saturday, June 14, 2014

Geo 730: June 14, Day 530: Coal

I'm not sure "coal" would technically be the correct name for this. I think of coal as a bedded rock rather than a discrete piece of a rock, and this looks to me as if it's a single tree limb or trunk that was deposited in the sediment. There were other bits around, so it wasn't unique, but it was the largest we saw. My understanding of sedimentary facies is rudimentary at best, but I'd guess this was offshore; we're not in a coastal swamp or anything. Supporting this, if you look back at yesterday's photo, you can see that the surrounding sediment was overall fairly course and poorly sorted. So the current must've been pretty brisk. But that same photo would indicate we're not too far offshore. If that were the case, the coarser gravel wouldn't have reached this far. So the "coal" in this case was probably a waterlogged chunk of wood that sunk and got mixed in with the sedimentary pile.

Photo unmodified. March 9, 2012. FlashEarth location. (This is probably accurate to within 10-20 miles. Sorry, no clue.)

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