Sequence Stratigraphy Flashcards
(16 cards)
Genetic stratigraphy
A type of strat that relates rock units to each other by Depositional relationships and subdividing based on bounding discontinuities
Allostratigraphy
The type of strat that subdivides rocks based on only their types of discontinuities
Sequence
A unit that’s comprised of related strata bounded above and below by unconformities or correlatable conformities
What are the differences between genetic strat and lithostrat?
Genetic Strat: incorporates stratigraphic breaks, focused on understanding geology, units broadly follow time
Lithostrat: incorporates internal discontinuities related to lith changes, focused on mapping rock units, units are diachronous
Forced regression
Rapid procreation associated with relative fall in sea level
System tract
A linkage of Depositional facies that accumulated at the same time
Type 1 Sequence Boundary
Relative sea level falls below shelf edge, shelf get exposed to subaerial exposures and sediment bypasses through valleys and deposited far into the basin
Type 2 Sequence Boundary
The shelf does not have river valleys and the sediment gets stuck on the shelf
RSME
Regressive surface of Marine Erosion
BSFR
Basal Surface of Forced Regression
3 parameters that control relative sea level
- Tectonism
- Eustatic sea level
- Variations in sediment supply
FSST
How is it formed?
Characteristics of it
Falling stage system tract
Formed during relative sea level fall.
Coarsest deposits, overlies the RSME, goes seaward into the BSFR, shows an increase in submarine fans
LST
How does it looked when preserved?
Characteristics of it (accommodation, sediment delivery, regression/transgression)
Lowstand system tract
Preserved in the terrestrial realm as fluvial infill sediment as relative sea level falls
Increase sediment delivery, little accommodation, decline in submarine fan development, normal regression, low rates of progradation and aggradation
TST
Made up of what sedimentary rocks/fill?
Characteristics (accommodation, sediment supply, sea level rise/fall, etc)
Transgressive system tract
Made up of mudstone, estuary valleys, back-stepping shoreline deposits.
Accommodation and sea level rise»_space; sediment supply, rapid sea level rise, cycles of progradation (parasequences) and retrogradational parasequences
HST
When does it occur?
Characteristics (accommodation, sediment supply, transgression/regression, etc)
What is diagnostic about HST?
Highstand System Tract
Occurs when sea level is at a high point.
Sediment progradation, normal regression, high sediment supply fills accommodation space
Development of progradational parasequences sets
Correlative conformity
A boundary marked by a finer-grained coarsening upward sequence in a Lowstand System Tract
