What do we use the fossil record for? 3. Interpreting past environments .
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What do we use the fossil record for? 3. Interpreting past environments ://www.wsgs.uwyo.edu/Coal/coal_brochure/images/fig1_swamp.jpg /oceanworld.tamu.edu/students/coral/images/coral_reef_1.jpg /www.geology.ohio-state.edu/~vonfrese/gs100/lect29/xfig29_02.jpg any one time different sediments types e being deposited in different places. one environment stretches indefinitely r in any direction.
Transcript of What do we use the fossil record for? 3. Interpreting past environments .
What do we use the fossil record for?
3. Interpreting past environments
http://www.wsgs.uwyo.edu/Coal/coal_brochure/images/fig1_swamp.jpg
http://oceanworld.tamu.edu/students/coral/images/coral_reef_1.jpg
http://www.geology.ohio-state.edu/~vonfrese/gs100/lect29/xfig29_02.jpg
At any one time different sediments typesare being deposited in different places.
No one environment stretches indefinitelyfar in any direction.
http://strata.geol.sc.edu/Bahamas/images/040-Heirarchy-of-Facies.jpg
http://csmres.jmu.edu/geollab/fichter/SedRx/carbdepoenvir.html
http://csmres.jmu.edu/geollab/fichter/SedRx/meanderriver.html
Facies = all of the characteristics of a particular rock unit.
The characteristics of the rock unit come from the depositional environment.
Every depositional environment puts its own distinctive imprint on the sediment, making a particular facies. Thus, a facies is a distinct kind of rock for that area or environment.
http://gpc.edu/~pgore/geology/geo102/facies.htm
A = Sandstone facies (beach environment)B = Shale facies (offshore marine environment)C = Limestone facies (far from sources of terrigenous input)
Each depositional environment grades laterally into other environments.
http://gpc.edu/~pgore/geology/geo102/facies.htm
http://www3.interscience.wiley.com:8100/legacy/college/levin/0470000201/chap_tutorial/ch12/images/le03_42.jpg
Onlap (Transgressive) SequencesShifting Facies through Time
Beach moves farther away
Water gets deeper
Sediment becomes finer
Time Rock Unit
Time Rock Unit
Time Rock Unit
Time Rock Unit
Time Rock Unit
Time Rock Unit
Transgression
Time Transgressive Unit
BeachsandstoneNear Shelf
shaleFar Shelflimestone
FUS – Fining Upward Sequence= Transgressive Sequence
Offlap (Regressive) SequencesShifting Facies through Time
Beachsandstone
Near Shelfshale
Far Shelflimestone
Beach moves closer
Water gets shallower
Sediment gets coarser
Prograding Regression
Time Transgressive Rock Unit
Time Rock Unit
Time Rock Unit
Time Rock Unit
Time Rock UnitTime Rock Unit
CUS – Coarsening Upward Sequence= Regressive Sequence
Transgressive Sequence
Regressive Sequence
BeachsandstoneNear Shelf
shaleFar Shelflimestone
Beach moves closerWater gets shallowerSediment gets coarser
Prograding Regression
Time Transgressive Rock Unit
Beach moves farther awayWater gets deeperSediment becomes finer
Transgression
BeachsandstoneNear Shelf
shaleFar Shelflimestone
Walther's Law = sedimentary environments that started out side-by-side will end up overlapping one another over time due to transgressions and regressions.
The result is a vertical sequence of beds. The vertical sequence of facies Represents former adjacent depositional environments.
http://gpc.edu/~pgore/geology/geo102/facies.htm
Which sequence of rock layers represents a transgression?
