Earth Sciences 1022A/B Lecture Notes - Lecture 6: Gypsum, Cross-Bedding, Feldspar
10 Jan 2017
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Document Summary
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 (i) (ii) Compaction pore space is reduced and particles are pressed closer together. Cementation precipitate from solution into grains, fills pores, cement grains together. Formed from rock fragments and minerals deposited by rivers, glaciers, wind, gravity mainly made of clay minerals and resistant quartz. Sandstone made of sand grains of mainly quartz, if grains about the same size it is well sorted, if a mixture of sizes it is poorly sorted; called arkose if lots of feldspar. Conglomerate is solidified gravel from landslide, stream bed, or wave action has rounded stones. Breccia has angular particles not moved far from source rock. Formed by weathered material in solution precipitating from water or as biochemical rocks made from dead marine organisms.
