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SEDIMENTS & SEDIMENTARY ROCKS ROCK CYCLE Relative Percentages of Sedimentary Rocks SEDIMENT From Weathering & Erosion Precipitation from saturated solution Product of evaporation calcite, quartz halite, gypsum Unconsolidated- NOT cemented SEDIMENT Particle size Pebbles, cobbles, boulders Gravel- > 2mm Sand- 2mm - 0.063mm Silt - 0.063mm - 0.004mm Clay- < 0.004 Deposition Clay-sized particle vs. clay mineral SEDIMENT Transportation Abrasion Rounding Sorting Deposition Environment of deposition- specific Preservation SEDIMENT Transportation Abrasion Rounding Sorting Deposition Environment of deposition- specific Preservation SEDIMENT Lithification Compaction Decrease in pore space for very fine grain size (clay) Cementation Clastic texture Cements- silica, calcite, iron oxide Crystallization Crystalline texture SEDIMENT Lithification Compaction Decrease in pore space for very fine grain size (clay) Cementation Clastic texture Cements- silica, calcite, iron oxide Crystallization Crystalline texture SEDIMENT Lithification Compaction Decrease in pore space for very fine grain size (clay) Cementation Clastic texture Cements- silica, calcite, iron oxide Crystallization Crystalline texture TYPES OF SEDIMENTARY ROCKS Clastic or Detrital Chemical- inorganic precipitation or evaporation Biochemical- Organic remains shells, charcoal, plant fragments CLASTIC (Detrital) ROCKS Breccia and Conglomerate (> 2mm) Sedimentary Breccia- angular fragments Conglomerate- rounded fragments Sandstone (2mm - 0.063mm) Quartz sandstone Arkose (feldspar) Graywacke (appreciable amounts of silt/clay) Fine-grained Matrix Usually from turbidity currents CLASTIC (Detrital) ROCKS Breccia and Conglomerate (> 2mm) Sedimentary Breccia- angular fragments Conglomerate- rounded fragments Sandstone (2mm - 0.063mm) Quartz sandstone Arkose (feldspar) Graywacke (appreciable amounts of silt/clay) Fine-grained Matrix Usually from turbidity currents Quartz Sandstone CLASTIC ROCKS Fine-grained Rocks Shale- fissile (in ‘sheets’) Siltstone Claystone Mudstone (silt and clay) CHEMICAL SEDIMENTARY ROCKS Carbonate Rocks Limestone- made of calcite Inorganic varieties micrite, oolites, travertine Dolomite Recrystallization Chert- silica Evaporites Rock gypsum Rock salt BIOCHEMICAL SEDIMENTARY ROCKS Coal Develops from peat plant fragments Lignite Bituminous Coal Carbonate Rocks Limestone- made of calcite organic varieties Coquina Fossiliferous Limestone Chalk BIOCHEMICAL SEDIMENTARY ROCKS Coal Develops from peat plant fragments Lignite Bituminous Coal Carbonate Rocks Limestone- made of calcite organic varieties Coquina Fossiliferous Limestone Chalk SEDIMENTARY STRUCTURES BEDDINGPrinciple of Original Horizontality Bedding plane Cross-bedding Graded bed Mud cracks Ripple marks Fossils SEDIMENTARY STRUCTURES BEDDINGPrinciple of Original Horizontality Bedding plane Cross-bedding Graded bed Mud cracks Ripple marks Fossils DUNES SEDIMENTARY STRUCTURES BEDDINGPrinciple of Original Horizontality Bedding plane Cross-bedding Graded bed Mud cracks Ripple marks Fossils SEDIMENTARY STRUCTURES BEDDINGPrinciple of Original Horizontality Bedding plane Cross-bedding Graded bed Mud cracks Ripple marks Fossils Mudcracks SEDIMENTARY STRUCTURES BEDDINGPrinciple of Original Horizontality Bedding plane Cross-bedding Graded bed Mud cracks Ripple marks Fossils Body Fossils Trace Fossils FORMATIONS Large enough to show on a map Distinctive from neighboring rock units Named after geographic locations CONTACT separation between 2 distinct rock units Sedimentary contact Other contacts INTERPRETATION OF SEDIMENTARY ROCKS Source Area Environment of Deposition Glacial environments Alluvial fan Interbedded shales and sandstones; cross-bedded Lake Arkose River channel and flood plain Tillites Shales; interbedded siltstones and mudstones Delta INTERPRETATION OF SEDIMENTARY ROCKS Source Area Environment of Deposition Glacial environments Alluvial fan Interbedded shales and sandstones; cross-bedded Lake Arkose River channel and flood plain Tillites Shales; interbedded siltstones and mudstones Delta Glacial Environment & Till INTERPRETATION OF SEDIMENTARY ROCK Environment of Deposition Beach, Barrier Island, Dune Lagoon Interbedded sandstones and shales; burrowed Reef Shales Shallow marine shelf Very well sorted quartz sandstones Skeletal Limestones Deep marine environment Turbidites- sequence of GRADED sandstones to shales INTERPRETATION OF SEDIMENTARY ROCK Environment of Deposition Beach, Barrier Island, Dune Lagoon Interbedded sandstones and shales; burrowed Reef fine grained sediment Shallow marine shelf Very well sorted quartz sandstones Skeletal Limestones Deep marine environment Turbidites- sequence of GRADED sandstones to shales CALCAREOUS INTERPRETATION OF SEDIMENTARY ROCK Environment of Deposition Beach, Barrier Island, Dune Lagoon Interbedded sandstones and shales; burrowed Reef Shales Shallow marine shelf Very well sorted quartz sandstones Skeletal Limestones Deep marine environment Turbidites- sequence of GRADED sandstones to shales INTERPRETATION OF SEDIMENTARY ROCK Plate Tectonics and Sedimentary Rocks At convergent boundaries Uplift results in Very rapid rates of erosion Thick accumulations of clastic sediment At transform boundaries Rapid rates of erosion, deposition and burial Good basins for petroleum exploration At divergent boundaries Initial stages of rifting- thick wedges of gravel and coarse sediment Resources Non-Metallic Sand and gravel Limestone Clay Gypsum Energy Resources Oil and gas Coal Formation of Oil and Gas U.S. Coal Production