Sedimentary Rocks

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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