Death & Fossilization Flashcards
(14 cards)
Taphonomy
Study of all natural processes that involve an organism after it has died – this includes how it decays, is scavenged by others, becomes fossilized, and erodes.
Bloat and Float
Decay may cause dead bodies to swell with putrid gasses, which may cause the carcasses of even the largest animals to be easily picked up by shallow, weakly flowing water.
Disarticulation
Separation or re-ordering / moving around of the bones in a carcass.
Plastic Deformation
When pressure causes the shape of a buried fossil to change s.t. even when the pressure is removed, the fossil doesn’t return to its original shape.
Fluvial Deposits
River & stream deposits (flowing water)
Lacustrine Deposits
Lake deposits (non-flowing water)
Sediments are usually very fine-grained, and thus more likely to preserve integument / soft tissues like hair or feathers.
Aeolian or Wind-based Deposits
Usually ancient deserts, where there wasn’t enough sediment being deposited to preserve any skeletons.
Sedimentology
Science of how sedimentary rocks form.
Sedimentary rocks
Form when organic & mineral particles accumulate and are cemented or compacted together.
With few exceptions, all fossils are found in sedimentary rocks.
Mudstone & Shale
Sedimentary rocks formed by mud and silt.
Large deposits of these indicate a former lake bottom environment.
Sandstone
Sedimentary rocks that form from sand.
Can indicate former beach, river channel or ocean floor environment.
Coal
Special sedimentary rock that is formed from the compressed remains of plants.
Indicates a former swampy environment.
Limestone
Sedimentary rock formed by the accumulation of shells and exoskeletons of small marine invertebrates.
Almost always indicates a former shallow marine environment.
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