Earth Sciences 1022a Lecture Brief 2 Oct 09 SEDIMENTARY ROCKS Weathered material from various rocks forms sedimentary rocks that comprise 75% of all rocks on the continents after deposition, sediment undergoes physical, chemical, and biologic changes as it gets turned into rock (hardened, consolidated); lithification includes compaction- pore space is reduced and particles are pressed closer together cementation – precipitate from solution onto grains, fill pores, cement grains together Detrital Sedimentary Rocks: formed from rock fragments and minerals deposited by rivers, glaciers, wind, gravity; mainly made of clay minerals and resistant quartz shale is the most abundant sed. rock made of silt and clay deposited in quiet water in lakes, river floodplains, lagoons; grains packed together so water and oil cannot flow through, good cap rock for oil and gas – also used for pottery, bricks, tile sandstone made of sand grains of mainly quartz, if grains about the same size it is
This is the end of the preview. Sign up
access the rest of the document.