GEOL 3032 Chapter : Lec19 Ch13 Siliciclastic Rocks Part2
Document Summary
Siliciclastic rocks = sedimentary rocks composed mainly of silicate particles derived by the weathering breakdown of older rocks . (cid:149) comprise of all (cid:149) sedimentary rocks in the geologic record. Earth"s history including paleo-depositional environments. (cid:149) more than of the world"s reserves of oil and gas occur in these rocks. Review (cid:149) conglomerate (>2mm) (cid:149) sandstone (1/16 to 2 mm) (cid:149) mudrock (1/256 to 1/16mm), Conglomerates http://en. wikipedia. org/wiki/file:fanglomerate-above_mesquite_springs_in_death_valley_np. jpg (cid:149) > 2mm (cid:149) gravels (>30%) (cid:149) contain sed structure (cid:149) two types. Mudstones (cid:149) grain size < 1/16 mm (cid:149) Silt = siltstone (cid:149) clay = mudstone or shale. Mudstones (cid:149) scanning electron microscope (sem) (cid:149) mineralogy primarily of clay minerals and fine-size quartz and feldspar. Mudstones (cid:149) occurrence (cid:149) any setting with fine-grain sized sediment in abundance in a low-energy environment to facilitate settling. (cid:149) typically marine (deep); also lacustrine, quiet riverine, lagoonal, tidal-flat, and deltaic environments.
