SEDIMENTARY ROCKS METAMORPHIC ROCKS AND AGE DETERMINATION SEDMET

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SEDIMENTARY ROCKS, METAMORPHIC ROCKS, AND AGE DETERMINATION

SEDIMENTARY ROCKS, METAMORPHIC ROCKS, AND AGE DETERMINATION

SED-MET ROCKS-AGE • Sedimentary rock family • Definition and Explanation • comprised of sediments

SED-MET ROCKS-AGE • Sedimentary rock family • Definition and Explanation • comprised of sediments • accumulated from physical and or chemical processes mostly in large bodies of water • consolidated through lithification

SED-MET ROCKS-AGE • Factors and concepts related to rock formation • weathering--”breaking down” of

SED-MET ROCKS-AGE • Factors and concepts related to rock formation • weathering--”breaking down” of rock materials at or near surface of Earth • chemical--decomposition of materials chemical and formation of new substances through removal of or additions to the weathered material • physical or mechanical--disintegration of mechanical materials with no new substances forming

SED-MET ROCKS-AGE • Erosion • removal or transportation of material by stream water, glacial

SED-MET ROCKS-AGE • Erosion • removal or transportation of material by stream water, glacial ice, wind, and gravity • eroded materials may eventually accumulate in large amounts • Lithification • compaction and cementation of sediments to become rocks

SED-MET ROCKS-AGE • Stratification • accumulations in layers (strata or beds) and is the

SED-MET ROCKS-AGE • Stratification • accumulations in layers (strata or beds) and is the most common occurrence of this family of rock • Law of superposition • in a series of strata, each layer is older than the one above and younger than the one below--this reflects a relative age relationship between layers

Stratification in Sedimentary Rocks

Stratification in Sedimentary Rocks

SED-MET ROCKS-AGE • Sedimentary rock types • three types based on the way they

SED-MET ROCKS-AGE • Sedimentary rock types • three types based on the way they form; clastic (detrital), chemical inorganic, and organic • clastic • sediments accumulated primarily by physical processes as deposits from stream water, glacial ice, wind, etc. then lithified to rock

SED-MET ROCKS-AGE • Wentworth’s sediment size classification is used to name the specific clastic

SED-MET ROCKS-AGE • Wentworth’s sediment size classification is used to name the specific clastic rock in the detrital class

Wentworth’s Scale of Sedimentary Particles

Wentworth’s Scale of Sedimentary Particles

Different colors of beach sand in the world

Different colors of beach sand in the world

CLASTIC ROCKS

CLASTIC ROCKS

Detrital (Clastic) Sedimentary Rocks Larger grained Conglomerate Breccia

Detrital (Clastic) Sedimentary Rocks Larger grained Conglomerate Breccia

Detrital (clastic) Sedimentary Sandstones Graywacke Arkose Quartz Sandstone

Detrital (clastic) Sedimentary Sandstones Graywacke Arkose Quartz Sandstone

Detrital (clastic) Sedimentary Rocks Smaller Grained Claystone Siltstone Shale

Detrital (clastic) Sedimentary Rocks Smaller Grained Claystone Siltstone Shale

SED-MET ROCKS-AGE • biological (organic) rocks • accumulation of animal shells or plant material

SED-MET ROCKS-AGE • biological (organic) rocks • accumulation of animal shells or plant material then lithified--particle size is not important in naming biological rocks

SED-MET ROCKS-AGE BIOLOGICAL OR ORGANIC ROCKS

SED-MET ROCKS-AGE BIOLOGICAL OR ORGANIC ROCKS

SED-MET ROCKS-AGE White Cliffs of Dover

SED-MET ROCKS-AGE White Cliffs of Dover

COAL SERIES buried plants Peat bituminous lignite anthracite methane coal gas

COAL SERIES buried plants Peat bituminous lignite anthracite methane coal gas

SED-MET ROCKS-AGE Biological (organic) formed chert

SED-MET ROCKS-AGE Biological (organic) formed chert

SED-MET ROCKS-AGE • chemical (inorganic) rocks • formed from chemical reactions in the oceans

SED-MET ROCKS-AGE • chemical (inorganic) rocks • formed from chemical reactions in the oceans or large bodies of water

CHEMICAL OR INORGANIC ROCKS

CHEMICAL OR INORGANIC ROCKS

Lakes formed from Glaciation Lake Bonneville

Lakes formed from Glaciation Lake Bonneville

Evaporite deposits in Death Valley, California

Evaporite deposits in Death Valley, California

SED-MET ROCKS-AGE Chemically (inorganic) formed chert---nodules of chert caused by replacement of silica for

SED-MET ROCKS-AGE Chemically (inorganic) formed chert---nodules of chert caused by replacement of silica for bedrock—is present in the local Burlington limestone bedrock in this area

SED-MET ROCKS-AGE • Some special features in sedimentary rocks • cross bedding • relatively

SED-MET ROCKS-AGE • Some special features in sedimentary rocks • cross bedding • relatively thin layers inclined at an angle to the main bedding • formed by currents in water or wind

Cross bedding

Cross bedding

SED-MET ROCKS-AGE • graded bedding • a sedimentary layer characterized by a decrease in

SED-MET ROCKS-AGE • graded bedding • a sedimentary layer characterized by a decrease in sediment size from bottom to top • ripple marks • small waves of sand that develop on surface of sedimentary layer by the action of moving water or wind

Ripple marks

Ripple marks

SED-MET ROCKS-AGE • Significance of sedimentary rocks • only family of rock containing an

SED-MET ROCKS-AGE • Significance of sedimentary rocks • only family of rock containing an abundant record of life forms and the changes in life forms throughout geologic time • only family of rock in which natural gas, petroleum and coal are formed and found • used as building materials, tombstones and some limestones are used as a source of lime

Groundwater Coal Petroleum and Natural Gas

Groundwater Coal Petroleum and Natural Gas

Cement from Limestone Uranium Salt

Cement from Limestone Uranium Salt

SED-MET ROCKS-AGE • Metamorphic rock family • Definition and explanation • formed primarily through

SED-MET ROCKS-AGE • Metamorphic rock family • Definition and explanation • formed primarily through action of temperature and/or pressure on preexisting rocks • little or no melting during process • time is also an important factor • rocks will loose evidence of fossils or other features present before the change

SED-MET ROCKS- AGE • Types of metamorphism • contact or thermal • usually forms

SED-MET ROCKS- AGE • Types of metamorphism • contact or thermal • usually forms with intrusions of smaller rock bodies as stocks in country rocks • temperature associated with the intrusive body is the prime metamorphic agent—lower temperatures would form lower grade of metamorphic rocks

SED-MET ROCKS-AGE • regional metamorphism • usually forms with intrusions of larger bodies like

SED-MET ROCKS-AGE • regional metamorphism • usually forms with intrusions of larger bodies like batholiths or laccoliths • temperature and pressure are equally important in the metamorphic process and includes a much larger area of metamorphism—higher temperatures would form a higher grade of metamorphic rock

SED-MET ROCKS-AGE • Kinds of metamorphic rocks • all but one rock is comprised

SED-MET ROCKS-AGE • Kinds of metamorphic rocks • all but one rock is comprised of silicate minerals • foliated • minerals are aligned in a pattern

Foliated metamorphic rocks

Foliated metamorphic rocks

Foliated or Lineated Metamorphic Rocks Gneiss Slate Schist Gneiss Phyllite

Foliated or Lineated Metamorphic Rocks Gneiss Slate Schist Gneiss Phyllite

Nonfoliated metamorphic rocks

Nonfoliated metamorphic rocks

Non foliated Metamorphic Rocks Quartzite (from arkose) Marble

Non foliated Metamorphic Rocks Quartzite (from arkose) Marble

SED-MET ROCKS-AGE • Important uses • building materials and tombstones • marble can be

SED-MET ROCKS-AGE • Important uses • building materials and tombstones • marble can be used in art as a sculpturing material

SED-MET ROCKS-AGE • Age determination (geologic age) • important concepts used • relative age

SED-MET ROCKS-AGE • Age determination (geologic age) • important concepts used • relative age concepts • crosscutting and intrusive nature of igneous rocks • law of superposition pertaining to sedimentary rocks • absolute age dating • determination of amounts of radioactive parent and stable daughter

Relative Age dating

Relative Age dating

SED-MET ROCKS-AGE • Age determination method • relative and absolute age determination methods are

SED-MET ROCKS-AGE • Age determination method • relative and absolute age determination methods are used together to establish the absolute age of rocks which cannot themselves be dated • igneous rocks are the best rock family to use in absolute age determinations • Index fossils are used to facilitate the determination of the age of sedimentary rocks

Determine the absolute age of sedimentary bed , B given: 1. igneous intrusive, V

Determine the absolute age of sedimentary bed , B given: 1. igneous intrusive, V dated at 2. 15 million years old 2. lava flow, P dated at 2. 25 million years old (both V and P were dated using the absolute age determination method we discussed in the mineral section)

Correlation of Index Fossils From 2 Different Areas

Correlation of Index Fossils From 2 Different Areas