Igneous Sedimentary Metamorphic. Igneous Sedimentary Metamorphic FIRE.
Lecture 7 Sediments and Sedimentary Rocks. Lecture Outline IDefinitions A)Sediment B)Transportation...
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Transcript of Lecture 7 Sediments and Sedimentary Rocks. Lecture Outline IDefinitions A)Sediment B)Transportation...
Lecture Outline
I DefinitionsA) SedimentB) Transportation
i. Fluid Dynamicsii. Modes of Transportiii. Transport-Related Properties
C) DepositionD) Lithification
II Sedimentary RocksA) Clastic Rocks
i. Breccia and Conglomerateii. Sandstoneiii. Fine-Grained Clastic Rocks
B) Chemical Sedimentary Rocksi. Carbonatesii. Evaporites
C) Organic Sedimentary RocksIII Sedimentary StructuresIV Interpretation of Sedimentary Rocks
A) Source AreaB) Depositional EnvironmentC) 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
Sediment TransportModes of Transport
Dissolved Load
Suspended Load
Bed Load
•Saltation
•Rolling (Surface Creep)
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
Lithification of Sediment
lithification - the conversion of newly deposited sediment into a solid rock. It maybe concurrent with, soon after, or long after deposition.
Cementation
Compaction
Crystallization
Physical Geology
Lithification of SedimentCompaction
compaction - reduction in bulk volume or thickness offine-grained sediments, owing to increasing weight of overlying material that is continuously beingdeposited, or to pressures resulting from earth movements. Tighter packing of sedimentary particles results in a decrease in porosity.
Physical Geology
Lithification of SedimentCementation
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 sedimentaryrock, thus binding the grains into a rigid mass. The most common cements are silica, carbonates, and iron oxides.
Physical Geology
Lithification of SedimentCrystallization
crystallization - the development and growth of crystals by precipitation from solution at or near the Earth's surface.
Physical Geology
Sedimentary RocksClastic Sedimentary Rocks - Examples
conglomerate
breccia
sandstone
graywacke
siltstone
shale
Physical Geology
Sedimentary RocksChemical Sedimentary Rocks - Carbonates
(Bioclastic Limestones)
chalk coralline limestone
coquina
Physical Geology
Sedimentary RocksChemical Sedimentary Rocks - Carbonates
(Inorganic Limestones)
tufaoolitic
limestone
travertine
Physical Geology
Sedimentary RocksChemical Sedimentary Rocks - Evaporites
rock saltNaCl
anhydriteCaSO4
rock gypsumCaSO4
. H2O
Physical Geology
Sedimentary StructuresDefinitions
sedimentary structure - a feature in sedimentary rock, formed eithercontemporaneously 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 StructuresStratification
stratification - the arrangement
of sedimentary rocks in strata;
bedding. It may be indicated
by differences in texture,
cementation, color, or
composition.
Physical Geology
Bedding Plane Sedimentary StructuresMudcracks
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
Sedimentary StructuresGeopetal 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