Sedimentary Rocks

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Sedimentary Rocks

• Sedimentary Rocks - Those rocks that form from
  the aggregation of sediments that have been
  transported, deposited, and later lithified.
• Sediments are essentially fragments and particles
  of other rocks and/or minerals.

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How is a sedimentary rock produced?

• The Sedimentation Process - producing sediments.
• Weathering and Erosion
• Transportation
• Deposition
• Lithification Process - How to convert sediments
  into rocks.
• Compaction
• Dehydration
• Cementation

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Sedimentary Rocks

• Two types of sedimentary rocks based on the
  sources of their major components -
• 1. Detrital sedimentary rocks - composed of
  particles call detritus, which means rock
  particles and/or minerals from other rock types.
  Also known as Clastic!
• 2. Chemical sedimentary rocks - composed of
  precipitates or chemicals that were in solution
  within a liquid, usually water. Note Biochemical
  used by textbook.

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Sedimentary Rocks

• Detrital Sedimentary Rocks -
• These rocks are composed of other rock types.
  Quartz is one of the most resistant rocks to
  weathering and is a dominate component of many
  sedimentary rocks.
• Gravel Conglomerate or breccia 2-gt 256 mm
• Sand Sandstone 1/16-2 mm
• Mud Mudstone to shale lt 1/16 mm

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Sedimentary Rocks

• Chemical Sedimentary Rocks
• These rocks are composed of materials carried in
  solution within lakes and oceans and/or of a
  biological origin.
• Limestone from dissolved CaCO3
• Conquina is a coarse rock composed mostly of
  loosely cemented shells and shell fragments.
• Chert, flint, agate, etc. is from SiO2
• Evaporites are salts - rock gypsum
• Coal - from organic material

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Sedimentary Rocks

• The importance of these rocks is that they
  typically make-up 75 volume of the upper most
  part of continental crust and are expressed as
  strata or beds or rock layers.
• Strata are the record of paleo-environments.

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Sedimentary Rocks

• The study of strata, beds, and their respected
  paleo-environments is the science of
  stratigraphy.
• Stratigraphic formation -sequence of strata
  distinctive enough to be traced across a large
  region.
• Special kinds of Bedding - Cross beds and graded
  beds.

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Sedimentary Rocks

• Sedimentary Environments - these are environments
  where sediments were deposited.
• Glaciers, mountain streams, alluvial fans,
  sand-dunes, lake, ponds, rivers, etc.
• Reflective of a specific type of depositional
  energy.

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Sedimentary Rocks - What Next?
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Sedimentary Rocks

• What processes produce sediments?
• Weathering - disintegration and decomposition of
  rock at or near surface (Mechanical and chemical)
• Mass wasting - transfer of rock material
  down-slope under the influence of gravity.
• Erosion - incorporation and transportation of
  material by a mobile agent, usually water, wind,
  and/or ice.