BISC 102 Chapter Notes - Chapter 27: Phanerozoic, Radiometric Dating, Petrified Wood
16 Jan 2017
School
Department
Course
Professor
Document Summary
Most of the processes that form fossils begin when part or all of an organism is buried in ash, sand, mud or some other type of sediment. How fossilization occurs: a tree lives in a swampy habitat. The tree drops leaves, pollen, and seeds into the mud where decomposition is slow: the tree falls. The trunk and branches break up as they rot: flooding brings in sand and mud, burying the remains of the trees, over millions of years, the mountains erode and the swamp is filled with sediment. Preservation after burial: once burial occurs, several things can happen. If decomposition does not occur, the organic remains an be preserved intact - like the fossil pollen. If sediments accumulate on top of the material and become cemented into rocks such as (cid:373)udsto(cid:374)e, or shale, the sedi(cid:373)e(cid:374)ts" (cid:449)eight (cid:272)a(cid:374) (cid:272)o(cid:373)press the organic material below into a thin carbonaceous film.
