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34 Cards in this Set
- Front
- Back
What percent of land areas are covered in sediments/sedimentary rock?
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75%
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What percentage of the crust is made up of sediments/sedimentary rocks?
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A small amount
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Diagenisis
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Deposition continues and old sediments are buries under younger layers and gradually lithified by compaction.
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Detrital Sedimentary Rocks
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Wide variety of minerals and clasts can be found in them (majority are clay minerals and quartz crystals)
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Detrital Sedimentary Rocks - What rocks?
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Conglomerate
Breccia Sandstone Shale Mudstone / Siltstone |
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Detrital Sedimentary Rocks - Shale
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silt and clay sized particles, fine grained.
Account for well over half all sedimentary rocks! Poorly cemented, not well lithified, weak. Ability to split into thin layers. |
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Detrital Sedimentary Rocks - Difference between Shale, Mudstone and Siltstone
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Shale: Breaks into thin layers
Mudstone: breaks into chunks/blocks Siltstone: lacks places that breaks can occur...? |
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Detrital Sedimentary Rocks - Sandstone
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Sand sized grains dominate.
Well sorted: travelled further Rounded: travelled further and by wind/water Opposite for opposites. Predominately quartz because it's durable |
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Detrital Sedimentary Rocks - Types of Sandstone
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Quartz Sandstone: Well travelled, mostly quartz
Arkose: 25%< feldspar, some sparkling mica + quartz. Poorly sorted + angular particles. Graywacke: Dark coloured rock. Poor sorting, angular grains. |
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Detrital Sedimentary Rocks - Conglomerate
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Largely consists of gravels, boulder-pea sized. Particles are usually easily identified as rock types.
Poorly sorted particles in mud/sand. Large particles should be round. |
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Detrital Sedimentary Rocks - Breccia
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Same as conglomerate (large particles, easily identified as rocks, surrounded by mud/sand)
but the particles should be angular as they didn't travel far. |
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Chemical Sedimentary Rocks
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Inorganic: evaporation, chemical activity (dripstone in caves, salt after a lake evaporates)
Organic: water dwellng organisms also form chemical sediments (skeletons on the floor of a lake) |
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Chemical Sedimentary Rocks - What rocks?
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Limestone (Carbonate Reefs, Coquina, Chalk, Travertine, Oolitic Limestone)
Dolostone Chert |
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Chemical Sedimentary Rocks - Limestone
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10% of all sedimentary rocks.
CaCO3 (mostly calcite) Many types exist, mosthave marine biochemical origin. Very obvious reaction to HCl |
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Chemical Sedimentary Rocks - Carbonate Reefs
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Corals create large quantities of marine limestone.
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Chemical Sedimentary Rocks - Coquina
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Coarse rock composed of poorly cemented shells and shell fragment
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Chemical Sedimentary Rocks - Chalk
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soft, porous rock made up of almost entirely of hard parts of microscopic marine organisms
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Chemical Sedimentary Rocks - Inorganic Limestone
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formed when chemical changes/higher water temps increase concentration of calcium carbonate until it precipitates.
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Chemical Sedimentary Rocks - Travertine
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Inorganic. Seen in caves.
Groundwater is the source of calcium carbonate and water droplets become exposed in the spaces of a cavern. |
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Chemical Sedimentary Rocks - Oolitic Limestone
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Inorganic.
Composed of little spherical grains that look like tiny eggs. Formed by tiny shell fragments move back and forth in the water which is supersaturated with calcium carbonate |
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Chemical Sedimentary Rocks - Dolostone
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Close to limestone but dolostone only effervesces in HCl when it is powdered.
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Chemical Sedimentary Rocks - Chert
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Very compact and hard rock.
Flint: Dark colour comes from organic matter. Jasper: Red variety, colour from iron oxide Agate: banded form |
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Evaporates
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Halite
Rock Gypsum |
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Organic Sedimentary Rocks
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Organic buildup that is decomposed.
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Organic Sedimentary Rocks - What rocks?
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Lignite Coal
Bituminous Coal Anthracite Coal |
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Organic Sedimentary Rocks - Lignite Coal
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Shallow burial in peat (soft brown organic material),
peat slowly changes to lignite - soft brown coal |
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Organic Sedimentary Rocks - bituminous coal
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deeper burial turns lignite into harder, more compacted rock called bituminious coal
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Anthracite Coal
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Hard, shiny, METAMORPHIC rock
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Diagenesis
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x
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Lithification
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x
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Classification of Sedimentary Rocks
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Clastic, Non-Clastic, Crystaline
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Classification of Sedimentary Rocks - Clastic
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Fragments of rock visible.
All detrital rocks. |
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Classification of Sedimentary Rocks - Non-Clastic
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x
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Sedimentary Environments
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Continental,
Marine, Transitional (shoreline) |