GEOL 104 Lecture Notes - Lecture 15: Facies, Continental Shelf, Ripple Marks
18 Apr 2016
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Document Summary
Origins of sedimentary rock: three types. Composed of cemented fragments of shell material: the white chalk cliffs. Chalk is composed of the tests of microscopic marine organisms. Material deposited in water, precipitated in layers: dolostone. Originally limestone but calcium ions replaced with magnesium. Silica deposited on surface of seafloor at great depth. Gets pushed into sediment by weight of seawater above. Form when restricted seaways become over saturated and salt deposits start. Form on salt flats when dissolved materials are precipitated. Uyuni, bolivia, produced lithium rich liquid below the salt flats through evaporation. Wet season -shallow water basin: evaporites, salt flats metamorphism. Dry season -dry cracked ground (mud cracks) Coal: an organic sedimentary rock: from organic rich remains of organisms, stages of coal formation. Turning sediments into sedimentary rock: diagenesis and lithification: diagenesis. Chemical and physical biological changes that takes place after sediments are deposited and buried. Occurs within upper few km of crust: lithification.
