GEO 101 1st Edition Lecture 8 Outline of Last Lecture 1 Review Questions Outline of Current Lecture 1 Weathering Sedimentary Rocks 2 External processes 3 Weathering 4 Sedimentary Rocks 5 Clastic Sedimentary Rocks Current Lecture Weathering Sedimentary Rocks Arches national park Utah Rocks weathered away to make shapes o Wind breaking it down External Processes Weathering breakdown of rock at surface Erosion removal of material by water wind ice or gravity Soil Altered weathered minerals Weathering will even break down extremely hard and dense rocks example Granite Bryce Canyon National Park Urah Weathering Physical Weathering breaking of rocks into smaller pieces o Types Frost wedging Salt wedging Unloading pressure release jointing Thermal expansion daily variation Biological activity root wedging animals Chemical Weathering o Breaks down internal structure of minerals These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o o o Water most important transport ions molecules Major Processes Dissolution Aided by small amounts of acid in water Calcite dissolves in water if acid present rocks limestone marble statues Oxidation Electrons lost from one element rusting Hydrolysis Hydrogen Ions Attacks replaces other ions Chemical reaction between Hydrogen H ions and hydroxyl OH ions of water and mineral s ions Soil combination of mineral organize matter water and air Sedimentary Rocks Sediments are the building blocks of sedimentary rocks Sediments are diverse as are the rocks made from them Four classes o Clastic made from weathered rock fragments clasts o Biochemical cemented shells of organisms o Organic the carbon rich remains of planets o Chemical minerals that crystallize directly from water Clastic Sedimentary Rocks Clastic sedimentary rocks reflect several processes o Weathering generation of detritus via rock disintegration o Erosion removal of sediment grains from rock o Transportation dispersal by wind water and ice o Deposition settling out of the transporting fluid o Lithification transformation into solid rock Burial more sediment is added onto previous layers Compaction overburden weight reduces pore space Sand 10 to 20 Clay 50 80 Cementation minerals grow in pores gluing sediments