Sediments and Sedimentary Rocks n Rock Cycle Definitions
- Slides: 60
Sediments and Sedimentary Rocks n Rock Cycle
Definitions n Sediments: Solid fragmental material transported and n Lithification: The conversion of a newly deposited n Diagenesis: All the changes (chemical, physical, or deposited by wind, water, or ice, chemically precipitated from solution, secreted by organism, and that forms in layers in loose unconsolidated form. sediment into a solid rock involving processes such as cementation, compaction, and crystallization. biological) undergone by a sediment after its initial deposition, exclusive of weathering and metamorphism. Definitions from Dictionary of Geologic Terms
Diagenesis n n Compaction: occurs when the weight of the overlying sediments pushes down on sediments; compaction is accompanied by the expulsion of water from these sediments Cementation: Occurs when solution “crystallizes” around sediment n Common elements in sedimentary rocks n n Silica (Si. O 2) Calcite (Ca. CO 3) Iron (Fe 2 O 3) Recrystallization (pressure solution): Occurs when sediments are exposed to very high pressures; as a result, the melting points of the constituent minerals are lowered and liquification occurs.
Environmental Clues in Sedimentary Rocks n Fossils Salt Water - Corals, Echinoderms n Fresh Water - Insects, Amphibians n Terrestrial - Leaves, Land Animals n n Color And Chemistry Red Beds - Often Terrestrial n Black Shale - Oxygen Poor, Often Deep Water n Evaporites – Arid Climates n
Bedding or Stratification n n Almost Always Present in Sedimentary Rocks Originally Horizontal Tilting by Earth Forces Later Variations in Conditions of Deposition Size of Beds (Thickness) n Usually 1 -100 Cm n Can Range From Microscopic to 50 m
Sedimentary Rocks Clastic Rocks n Made of Fragmentary Material n Deposited by n Water (Most Common) n Wind n Glacial Action n Gravity Biochemical Sedimentary Rocks n Evaporation n Precipitation n Biogenic Sediments
Clastic Rocks Classified by: n Grain Size n Grain Composition n Texture
Sediment Sizes and Clastic Rock Types Rock Type Sediment Grain Size Shale Clay less than 0. 001 mm Siltstone Silt . 001 -0. 1 mm Sandstone Sand . 01 -1 mm Conglomerate Gravel 1 mm + Sedimentary rocks made of silt- and claysized particles are collectively called mudrocks, and are the most abundant sedimentary rocks.
Range of Clast Size in Sediments Coarse Medium Fine Boulder > 256 mm Boulder >28 mm 64 mm < Cobble < 256 mm 26 mm < Cobble < 28 mm 2 mm < Pebble < 64 mm 21 mm < Pebble < 26 mm 1/16 mm < Sand < 2 mm 2 -4 mm < Sand < 21 mm 1/256 mm < Silt < 1/16 mm 2 -8 mm < Silt < 2 -4 mm Mud < 1/256 mm Mud < 2 -8 mm
Chemical Sediments Evaporites -Water Soluble n Halite n Gypsum n Calcite Precipitates Gypsum n Limestone n Iron Formations Alteration After Deposition n Dolomite Biogenic Sediments n Limestone - Shells, Reefs, Etc. Organic Remains n Coal n Petroleum
Coal Seams, Utah
Sedimentary Structures
Sedimentary Structures
Ea. ES 350 -3 23
Ea. ES 350 -3 24
Sedimentary Structures
Utah sandstone
Patch Reefs
Sediments and Sedimentary Rocks n Sedimentary Structures (cont’d) n Ripple marks - small ridges formed on the surface sediment layer by moving wind or water n Wave generated ripple marks are symmetric n Current generated ripple marks are asymmetric
Sediments and Sedimentary Rocks n Sedimentary Structures (cont’d) n Fossils - traces of plants or animals preserved in sedimentary rock; includes replacement by calcite or silica, voids spaces or molds reflecting the former shape, filling in the molds to form casts, flat carbon imprints. footprints, trails, and burrows
Differential Weathering
Sedimentary Rocks
- Igneous vs sedimentary or metamorphic
- Igneous rocks metamorphic rocks and sedimentary rocks
- Sedimentary rocks
- Concept map of igneous rocks
- Concept map of metamorphic rock
- Rock cycle
- Metamorphic sedimentary
- Chapter 6 sedimentary and metamorphic rocks answer key
- Detrital sedimentary rocks
- Sedimentary rocks
- Sedimentary rocks record past geological events and ____.
- Erosion sedimentary rocks
- Esrt sedimentary rocks
- Sedimentary rocks examples
- Non example of sedimentary rock
- Characteristics of sedimentary rocks
- Sedimentary rocks
- Characteristics of sedimentary rocks
- What are sedimentary rocks
- In sedimentary rocks lithification includes
- Characteristics of sedimentary rocks
- Sedimentary rocks
- How is chert formed
- Chapter 4 section 3 sedimentary rock answer key
- What kind of sedimentary rock is coal
- Fun facts about sedimentary rocks
- Metamorphic rocks properties
- How could you tell
- Classify sedimentary rocks
- Sedimentary rocks leaving cert
- Esrt sedimentary rocks
- A process that squeezes or compacts sediments
- Conglomerate composition
- Attritiom
- Magma facts
- Rocks formation
- Biochemical sedimentary rocks
- Non-banded grains
- Types of sedimentary rocks
- Organic sedimentary rocks
- Transportation sedimentary rocks
- Clastic sedimentary rocks
- Venn diagram of intrusive and extrusive igneous rocks
- Types of rocks in texas
- Allochemical sedimentary rocks
- Chemical sedimentary rocks formed
- Rock chart
- Sedimentary rocks
- How are sedimentary rocks formed
- Silicon oxygen tetrahedron
- How are sedimentary rocks formed
- How are sedimentary rocks made
- Groups of sedimentary rocks
- How are rocks formed
- What are sediments
- Sedimentary rocks turn into metamorphic
- Sedimentary rocks
- Importance of sedimentary rocks
- Is breccia an organic rock
- Sedimentary rocks
- How do chemical sedimentary rocks form