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79 Cards in this Set
- Front
- Back
Cenozoic
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66ma (KT) to present
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Mesozoic
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252ma-66ma (KT)
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Miocene
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Cenozoic epoch, 23ma-5.3ma. Hominoid clade splits around 15ma.
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Pliocene
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Cenozoic epoch, 5.3ma-1.8ma. Ardipithecus-4.4ma. A. anamensis- 4.0ma. A. afarensis-3.9-2.9ma.
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Pleistocene
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Cenozoic epoch, 1.8ma-.11ma. AMH humans-~190ka.
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Holocene
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Cenozoic epoch, .11ma-p
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Normal fault
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hangingwall below footwall.
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Reverse fault
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Hangingwall above footwall.
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Dip
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Angle between bedding plane and horizontal.
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Anticline
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Convex up
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Syncline
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Convex down.
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Graben
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Depression at normal fault system
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Hoist
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Elevation at normal fault system
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Sedimentary basin
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Subsidence and infilling.
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Catchment
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Or drainage basin. Are drained by a river system.
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Headwater
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Most distant point in catchment from which water runs year round.
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River gradient
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Measure of speed of water at point.
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Meanders
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Bend in sinuous water course.
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Floodplain
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Flat area adjacent to stream or river.
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Alluvial fan
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Fan shaped deposit at river slowdown point.
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Point bar
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Crescent shaped deposit point at inside point of meandering stream.
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Cut bank
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Eroding area at outside of a meandering stream.
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Bed load
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Larger sediments which contact the river bed during movement.
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Suspended load
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Sediments suspended in river motion.
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Capacity
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Amount of sediment a stream can move.
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Competence
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Maximum size of particles a stream can movie.
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Breccia
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Composed of angular fragments.
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Boulder
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>10in
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Cobble
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2.5-10in
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Pebble
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4-64mm
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Gravel
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2mm-4mm
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Sand
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1/16mm-2mm
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Silt
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1/256mm-1/166mm
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Shale
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Fine grained sedimentary rock whose constituents were clays or muds. Irregular fracture. Most common.
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Limestone
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Sedimentary rock composed mostly of calcium carbonate and silica. CaCO3 comes from marine organisms.
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Sedimentary facies
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Lateral variation in content of sedimentary rock units. Caused by different environments of deposition.
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Biofacies
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Lateral changes in fossil content.
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Obsidian
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Felsic (silicate) magma cooled faster than rate of crystal formation.
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Tuff
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Compacted ash.
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Ignimbrite
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Welded ash.
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Basalt
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Flows then hardens.
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Volcanic cone
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Pileup around vent.
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Caldera
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Collapse of ground following magma extrusion.
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Uniformitarianism
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Hutton, 18th century. Process are the same.
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Unconformity
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Break in sedimentary geologic record.
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Diastem
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A temporal break between adjacent strate representing nondeposition or local erosion.
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Biostratigraphy
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Uses fossils to relatively date strata.
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tephrastratigraphy
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Uses volcanic ash to relatively date strata.
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Isochron dating
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...?
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Archeostratigraphy
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Using archeological materials to relatively date.
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Paleomagnetic
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Uses flips in magnetic field represented in mineral orientation to correlate strata.
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Radiometric dating
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Radiocarbon, potassium-argon, uranium-lead.
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Radiocarbon dating
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C14->C12. Effective for carbonaceous materials up to 60,000 years old.
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Accelerator Mass Spec
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Used in C-14 dating. Atoms ionized and accelerated into carbon sheet which strips electrons, the anions then accelerate into mass analyzer.
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Potassium-argon dating
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40K->40Ar. Effective for rocks >100,000 years old. Rock is melted and released gas is measured using mass spec.
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Argon-argon dating.
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39Ar->40Ar. Sample is irradiated with neutrons which convert some 39K to 39Ar. Rock gas is measured with 39AR being used as indicative of 40K. Measured in same sample.
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Fission track dating
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U-238. Measures damage trails left by fission or uranium in minerals. Effective only in uranium carying minerals.
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Uranium Series
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U-238->Pb-206 through 18 intermediates.
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Thermoluminescence
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Measures accumulated radiation dose of time elapsed since formation.
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Amino acid racemization
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Dates by measuring racemization of L and D amino acids.
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foraminifera
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Diverse phylum of test building protists. Used in biostratigraphy.
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Anthropogenic
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Human knapped stone objects.
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Lithic reduction
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Uses hammerstone or punch to detach lithic flakes from a lithic core.
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Blades
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Flakes twice as long as they are broad.
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Lithic flake
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Portion removed from core.
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Hertzian cone
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Cone of force which propagates through a brittle amorphous solid.
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Striking platform
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Proximal portion of a lithic flake on which the blow fell.
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Bulb of force
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Portion of hertzian cone present on flake.
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Proximal end (lithics)
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End which recieved blow
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distal end (lithics)
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Terminal end of a flake.
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Ventral surface (lithics)
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bulb of force but no flake scars.
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Cortex (lithics)
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Weathered outer rind which covers unweathered material.
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Primary flake
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Dorsal surface entirely covered in cortex.
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Secondary flake
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Dorsal surface contains some cortex.
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Tertiary flake
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Dorsal surface lacks cortex.
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Conchoidal flake
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Large bulb of force, indicative of hammerstone use.
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Blade
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A flake with parallel margins which are twice as long as they are broad.
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Conchoidal fracture
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No planes of separation
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Soft-hammer percussion
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Uses antler, bone, or wood. Flake is bent or peeled from core.
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