Sedimentary Rocks : Sedimentary Rocks Deposited on or Near Surface of Earth by Mechanical or Chemical Processes


What Rocks Tell Us : What Rocks Tell Us


Sedimentary Rocks are the Principal Repository for Information About the Earth’s Past Environment: Sedimentary Rocks are the Principal Repository for Information About the Earth’s Past Environment


Environmental Clues in Sedimentary Rocks: Environmental Clues in Sedimentary Rocks Grain Size - Power of Transport Medium Grading - Often Due to Floods Rounding Sorting Cross-bedding - Wind, Wave or Current Action } Transport, Reworking


Environmental Clues in Sedimentary Rocks: Environmental Clues in Sedimentary Rocks Fossils Salt Water - Corals, Echinoderms Fresh Water - Insects, Amphibians Terrestrial - Leaves, Land Animals Color And Chemistry Red Beds - Often Terrestrial Black Shale - Oxygen Poor, Often Deep Water Evaporites – Arid Climates


Bedding or Stratification: Bedding or Stratification Almost Always Present in Sedimentary Rocks Originally Horizontal Tilting by Earth Forces Later Variations in Conditions of Deposition Size of Beds (Thickness) Usually 1-100 Cm Can Range From Microscopic to 50m


Sedimentary Rocks: Sedimentary Rocks Clastic Rocks Made of Fragmentary Material Deposited by Water (Most Common) Wind Glacial Action Gravity Biochemical Sedimentary Rocks Evaporation Precipitation Biogenic Sediments


Clastic Rocks: Clastic Rocks Classified by: Grain Size Grain Composition Texture


Sediment Sizes and Clastic Rock Types: Sediment Sizes and Clastic Rock Types Sedimentary rocks made of silt- and clay-sized particles are collectively called mudrocks, and are the most abundant sedimentary rocks.


Some Special Clastic Rock Types: Some Special Clastic Rock Types Arkose Feldspar-Rich Breccia Angular Fragments Graywacke Angular, Immature Sandstone


Maturity: Maturity Stability of Minerals Rock Fragments Rounding or Angularity Sorting Removal of Unstable Ingredients - Mechanical Working


Diagenesis: Diagenesis


Diagenesis: Diagenesis Compaction Cementing Quartz Calcite Iron Oxide Clay Glauconite Feldspar Alteration Limestone - Dolomite Plagioclase – Albite Recrystallization Limestone


Chemical Sediments: Chemical Sediments Evaporites -Water Soluble Halite Gypsum Calcite Precipitates Example: Ca(sol'n) + SO4 (Sol'n) = CaSO4 and#x19; Gypsum Limestone Iron Formations Alteration After Deposition Dolomite Biogenic Sediments Limestone - Shells, Reefs, Etc. Organic Remains Coal Petroleum


Fossil Fuels: Fossil Fuels


Coal Seams, Utah: Coal Seams, Utah


Coal: Coal Delta, continental environments Carbonized Woody Material Often fossilized trees, leaves present


Plant Fragments Are Often Visible in Coal: Plant Fragments Are Often Visible in Coal


Petroleum: Petroleum A hydrocarbon molecule What organisms make these? Answer: None


Petroleum: Petroleum Lots of organisms make these, however Fatty Acids Probable source: Marine plankton


Petroleum Traps: Petroleum Traps


Facies Changes: Facies Changes


Landforms Associated with Sedimentary Rocks: Landforms Associated with Sedimentary Rocks Mesa Flat-topped hill capped with hard rock Cuesta Gently-tilted layer of hard rock: Door Peninsula The gentle upper slope, on top of the layer is called the dip slope Hogback A sharp ridge of hard rock, edge of a steeply-dipping layer


Mesas, Utah: Mesas, Utah


Grandfather Bluff, Wisconsin: Grandfather Bluff, Wisconsin


Cuestas, Wyoming: Cuestas, Wyoming


A Hogback, Wyoming: A Hogback, Wyoming


Flatirons, Boulder, Colorado: Flatirons, Boulder, Colorado


Garden of the Gods, Colorado: Garden of the Gods, Colorado