I Sediments Sedimentary Rocks a Most likely to preserve past events environments b Sediment i Eroded or loose fragments II Weathering c Sedimentary rocks i Consolidated ii Several km thick a Breakdown of rock i Small fragments ii Dissolved ions b Two types of weathering i Physical weathering Jointing breaks in rocks 1 2 Frost wedging water seeps into pores of rocks and freezes 3 Root wedging expanding widening joints tree roots 4 Salt wedging wind blows saltwater into rock surfaces 5 Thermal expansion intense heat 6 Animal attack burrowing and digging 7 Talus rock rubble at base of slope 8 9 Differential weathering Increases rate of chemical processes and surface area a Different rocks weather at different rates ii Chemical weathering 1 Chemical reactions i Rapid in wet warm climates FLORIDA a Contact with water or air b Destroys minerals c Hydration d Organisms i Minerals expand i Plant roots lichen fungi bacteria ii Secrete acids iii Derive nutrients from minerals e Oxidation f Depend on surface exposure g Dissolves grains cements h Hard minerals soft ones i Water causes expansion 2 Not all minerals are affected equally i Higher formation temperature less stable ii Stronger bonds more resistant quartz III Types of Sedimentary Rocks a Clastic i Weathering ii Erosion iii Transport by water and a bit of wind iv Deposition v Lithification vi Diagenesis 1 Compaction and cementation burial 1 Based on composition and genesis 2 Breccia 3 Conglomerate 4 Arkose 5 Quartz sandstone 6 Siltstone 7 Shale or mudstone vii Components of classification 1 Composition a Minerals 2 Clast size a Coarse fine b Biochemical i Organisms secrete shells ii Organisms die 1 Soft tissue rots shell remains iii Limestone 1 Carbonate shells iv Chert cryptocrystalline quartz 1 Plankton c Organic d Chemical i Plant debris 1 Coal 50 carbon i Precipitate out of solution 1 Evaporates ii Travertine a Concentration of ions b Gypsum halite 1 Hot springs caves 2 Groundwater degasses CO2 3 Precipitation of calcite iii Dolostone iv Chert 1 Mg rich groundwater 1 Quartz replaces calcite 2 Many colors a Black red green v Petrified wood 1 Si rich fluids 2 Move through trees IV Sedimentary Structures a Distinct layers i Form during deposition ii Clues about environment b Source of bedding i Change in 1 Sediment source 2 Climate 3 Water depth ii Special types 1 Cross beds a Thin bands of sediment b Angle to bedding c Wind transport 2 Graded beds a Turbidity currents b Base coarse c Top fine iii Bed surface markings 1 Ripple marks 2 Mud cracks 3 Fossils V Terrestrial Sedimentary Environments a Glacial environments i High latitude or altitude ii Material of any size b Mountain stream environments i Boulders cobbles floods ii Fines suspended iii Collision rounding c Mountain front environments i Gradient and energy decreases ii Arid 1 Alluvial fan 1 Coarse bottom d Dune environments i Deserts shore ii Wind transport e River environments i Bed load f Lake environments ii Suspended load 1 Fines i Coarse material 1 Shore ii Finer sediment In lake 1 g Coastal marine environments i Delta deposits 1 Rapid loss in energy 2 Deposition h Shallow marine carbonate environments i Produced by organisms i Deep marine environments i Turbidites ii Further offshore 1 Fine grained sediment 2 Plankton VI Sedimentary Basins a Rifts b Passive margins c d Foreland basins e Transgression regression Intracratonic