GEO 101 1st Edition Lecture 8Outline of Last Lecture 1. Review Questions Outline of Current Lecture 1. Weathering & Sedimentary Rocks 2. External processes3. Weathering4. Sedimentary Rocks 5. Clastic Sedimentary Rocks Current LectureWeathering & Sedimentary Rocks - Arches national park, Utah- Rocks weathered away to make shapeso 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, UrahWeathering - 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 Water – most important o – transport ions & molecules o 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 classeso 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 processeso Weathering – generation of detritus via rock disintegrationo Erosion – removal of sediment grains from rocko Transportation – dispersal by wind, water, and iceo Deposition – settling out of the transporting fluido 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”