Showing posts with label taphonomy. Show all posts
Showing posts with label taphonomy. Show all posts

Friday, November 21, 2008

The occasional taphonomic effect

Things with lots of hard parts tend to be preserved in the fossil record. (At least the hard parts do )
So:
Clams and snails and such


no problem
jelly fish



not so much. (took me forever to find a decent picture of one)
dinosaurs and other large terrestrial vertebrates



ok but not great. See the previous post about life position as well.

Saturday, October 25, 2008

the occasional taphonomic effect

Environment/life position
The first step to being fossilized is to get buried. So things that live buried, like most clams.



Are well represented in the fossil record. At the other end of the scale, large terrestrial vertebrates like dinosaurs.



Not nearly as common

still more to come...

Thursday, October 23, 2008

The occasional concept.

Taphonomy
Taphonomy is the paleontologists way of saying "shit happens" generally to the fossils ~I'm~ trying to study. (Yes we take it personally:) In a perfect world a Thompson's Gazelle, for example, dies of a heart attack while drinking at a river, it falls into the river where it is covered with fine grained sediment and is perfectly preserved intact until a paleontologist comes along and digs it up. This never happens. Thompson's Gazelles don't die of heart attacks, they die of Lion bites to the throat, after which they are scattered by the Lions all over the Serengeti. If they do fall into the river they're torn apart by crocodiles once the bones are buried there are all sorts of chemical processes that can degrade the bone so by the time we get to it there's usually not much left.
Taphonomy was once described to me as the loss of information in the fossil record. I'm not quite that pessimistic. For example, if your fossil shows signs of being eaten by crocodiles then you know that there were crocodiles around. But I'm a paleoecologist so I'm into that sort of thing.
Regardless, taphonomy is the transition from the life assemblage, which is all the biology going on in a certain area, to the fossil assemblage, which is what the paleontologist finds in the rock record. If you don't understand taphonomy you don't understand anything in paleo.

more to come....