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Neils Stensen's 3 principals
- Superposition
- Original Horizontality
- Lateral Continuity
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Lateral Continuity
strata extend in all directions until they terminate by thinning at the basin of margin or end abruptly against a barrier or slowly grade to a different sentiment
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Principle of
superposition
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Principle of superposition
- in any sequence of undisturbed strata the bottom layer is older while subsequent layers are younger and younger
- Strata are often tilted
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Principle of original
horizontality
most sedimentary particles settle from fluids under influence of gravity. Particles settle parallel and horizontal to formation of the underlying surface
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Stratigraphy
- the study of layered sedimentary
- rocks, including their texture, composition and arrangement. Enables geographic events to be placed in their correct sequence
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Crosscutting
Relationship
a geologic feature that cuts across another body of rock is younger than the rock it cuts through.
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Complement Inclusion
fragments found in a body of rock are older than the enclosing rock
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Faunal Sucession
(Will Smith) strata can be dated by the biota found within them, evolution
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Primary mountains
Crystalline (igneous and
metamorphic) likely to be the oldest in mountain systems, exposed along the
central axis of ranges
Crystalline (igneous and metamorphic) likely to be the oldest in mountain systems, exposed along the central axis of ranges
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Secondary mountains
sedimentary rocks
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Tertiary
unconsolidated gravel, sand, clay beds and lava floes
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Historical geology
the Earth's evolution, changes in distribution of lands, seas topography, life forms, etc - work backwards in time to determine what has caused results
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Physical geology
the origin, classification and composition of earth materials as well as the processes occurring on the surface and within the interior of the earth
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