Lecture 7 Sediments and Sedimentary Rocks

Lecture Outline IDefinitions A)Sediment B)Transportation i.Fluid Dynamics ii.Modes of Transport iii.Transport-Related Properties C)Deposition D)Lithification IISedimentary Rocks A)Clastic Rocks i.Breccia and Conglomerate ii.Sandstone iii.Fine-Grained Clastic Rocks B)Chemical Sedimentary Rocks i.Carbonates ii.Evaporites C)Organic Sedimentary Rocks IIISedimentary Structures IVInterpretation of Sedimentary Rocks A)Source Area B)Depositional Environment C)Plate Tectonics and Sedimentary Rocks Physical Geology

Definitions sediment - solid fragmental material transported and deposited by wind, water, or ice, chemically precipitated from solution, or secreted by organisms, that forms in layers in loose, unconsolidated form. unconsolidated material - A sediment that is loosely arranged or unstratified, or whose particles are not cemented together, occurring either at the surface or at depth. sedimentary rock - A layered rock resulting from the consolidation of sediment. Physical Geology

Grain Size Udden-Wentworth Scale Physical Geology

Sediment Transport Water Wind Gravity Ice Physical Geology

Sediment Transport Fluid Dynamics Physical Geology

Sediment Transport Modes of Transport Dissolved Load Suspended Load Bed Load Saltation Rolling (Surface Creep) Physical Geology

Sediment Transport Transport-Related Properties Physical Geology

Deposition of Sediment deposition - the laying-down of rock-forming material by any natural agent deposit - Earth material of any type that has accumulated through the activities of water, wind, ice, or other agents, such as precipitation. depositional environment - the location in which deposition occurs Physical Geology

Deposition of Sediment Progressive Sorting Physical Geology

Lithification of Sediment lithification - the conversion of newly deposited sediment into a solid rock. It may be concurrent with, soon after, or long after deposition. Cementation Compaction Crystallization Physical Geology

Lithification of Sediment Compaction compaction - reduction in bulk volume or thickness of fine-grained sediments, owing to increasing weight of overlying material that is continuously being deposited, or to pressures resulting from earth movements. Tighter packing of sedimentary particles results in a decrease in porosity. Physical Geology

Lithification of Sediment Cementation cementation - the process by which clastic sediments are converted into rock by precipitation of a mineral cement among the grains of the sediment. cement - chemically precipitated mineral material that occurs in the spaces among the grains of a sedimentary rock, thus binding the grains into a rigid mass. The most common cements are silica, carbonates, and iron oxides. Physical Geology

Lithification of Sediment Crystallization crystallization - the development and growth of crystals by precipitation from solution at or near the Earth's surface. Physical Geology

Sedimentary Rocks Clastic Chemical Organic Physical Geology

Sedimentary Rocks Clastic Rocks Physical Geology

Sedimentary Rocks Clastic Sedimentary Rocks - Examples conglomerate breccia sandstone graywacke siltstone shale Physical Geology

Sedimentary Rocks Chemical Sedimentary Rocks CarbonatesEvaporites Physical Geology

Sedimentary Rocks Chemical Sedimentary Rocks - Carbonates (Bioclastic Limestones) chalk coralline limestone coquina Physical Geology

Sedimentary Rocks Chemical Sedimentary Rocks - Carbonates (Inorganic Limestones) tufa oolitic limestone travertine Physical Geology

Sedimentary Rocks Chemical Sedimentary Rocks - Evaporites rock salt NaCl anhydrite CaSO 4 rock gypsum CaSO 4. H 2 O Physical Geology

Sedimentary Rocks Organic Sedimentary Rocks coal lignite peat Physical Geology

Sedimentary Structures Definitions sedimentary structure - a feature in sedimentary rock, formed either contemporaneously with deposition (primary structure) or by later sedimentary processes (secondary structure) bedding - the arrangement of sedimentary rock in layers bedding plane - division plane that separates each successive sedimentary layer or bed from the one above or below. It commonly marks a visible change in lithology or color. formation - a body of rock strata that consists dominantly of a certain lithologic type or combinations of types. It is the fundamental lithostratigraphic unit. Formations may be combined into groups and subdivided into members. Physical Geology

Sedimentary Structures Stratification Internal Structures Bedding Plane Structures Geopetal Structures Physical Geology

Sedimentary Structures Stratification stratification - the arrangement of sedimentary rocks in strata; bedding. It may be indicated by differences in texture, cementation, color, or composition. Physical Geology

Sedimentary Structures Stratification - Principle of Superposition Physical Geology

Sedimentary Structures Stratification - Principle of Original Horizontality Physical Geology

Sedimentary Structures Internal Structure graded bedding cross-stratification Physical Geology

Sedimentary Structures Cross-Bedding Physical Geology

Sedimentary Structures Graded Beds Physical Geology

Sedimentary Structures Bedding Plane Features Mudcracks Ripples Fossils Physical Geology

Lecture 7 III.F Bedding Plane Sedimentary Structures Ripples Physical Geology

Bedding Plane Sedimentary Structures Mudcracks mudcrack - an irregular fracture in a crudely polygonal pattern, formed by the shrinkage of clay, silt, or mud, generally in the course of drying under surface conditions. Physical Geology

Bedding Plane Sedimentary Structures Fossils Physical Geology

Sedimentary Structures Geopetal Structures geopetal - pertaining to any rock feature that indicates the relation of top to bottom at the time of formation of the rock symmetric ripple marks included fragments cross-bedding graded bedding mud cracks bed surface marks scour marks fossils Physical Geology

Interpretation of Sedimentary Rocks Grain Size Lecture 7 IV Physical Geology

Interpretation of Sedimentary Rocks Color Physical Geology

Depositional Environment Continental Transitional Marine Physical Geology

Plate Tectonics and Sedimentary Rocks Passive Margin Physical Geology

Plate Tectonics and Sedimentary Rocks Volcanic Island Arcs Physical Geology

Plate Tectonics and Sedimentary Rocks Continental Collision Physical Geology