Sedimentary Facies.ppt

Sedimentary Facies

1. Sedimentary Facies & Sea Level

2. Sedimentary Facies:
•general appearance or aspects
of a rock (composition & texture).
Sedimentary Facies & Sea Level

3. Sedimentary Facies:
• original environment of
deposition can be determined.
•used to describe vertical and
lateral variations in strata.
Sedimentary Facies & Sea Level

4. Sedimentary Facies:
• facies transform laterally by
gradual changes in their properties
into different, adjacent facies.
Sedimentary Facies & Sea Level

5. Two types of facies
1). Lithofacies:
distinguishing characteristics are
. . . lithologic
Sedimentary Facies & Sea Level

6. Sedimentary Facies & Sea Level
sandstone
facies shale facies

7. Two types of facies
1). Lithofacies: can be degree
of difference
Sedimentary Facies & Sea Level
limestone sandstone
vs. vs.
fine grained
limestone
coarse,
well sorted
sandstone

8. Two types of facies
2). Biofacies:
differences in biological (fossil)
composition.
Sedimentary Facies & Sea Level

9. Two types of facies
2). Biofacies:
•can have different adjacent
biofacies in the same lithology
•can be sensitive to small
environmental differences
Sedimentary Facies & Sea Level

10. Sedimentary Facies & Sea Level
Foraminifera facies
Mississippi Delta

11. Sedimentary Facies & Sea Level
Changes in sea level

12. Transgression:
•Advance of sea over the land
Regression:
•Retreat of the sea from the land
Sedimentary Facies & Sea Level

13. Idealized gradation:
•Near shore = coarse sediment
-to -
•Off shore = fine sediment
-yielding to -
•Shelf carbonate deposition
Sedimentary Facies & Sea Level

14. Idealized gradation:
Sedimentary Facies & Sea Level
near
shore
off
shore
continent

15. No sea level change:
Sedimentary Facies & Sea Level
near
shore
off
shore
continent
http://www.uh.edu/~jbutler/physical/transreg.gif
sediment through time

16. Sea level at Time A:
Sedimentary Facies & Sea Level
“the beach”
Sea level change: cross section

17. Sea level at Time B:
Sedimentary Facies & Sea Level
“the beach”

18. Sedimentary Facies & Sea Level
Transgression
• facies shift on-shore
• resulting rock unit (sandstone)
varies in age laterally

19. Shift fromTime AtoTime B:
Sedimentary Facies & Sea Level
“the beach”
“the beach”
Transgression
• facies shift on-shore
• resulting rock unit (sandstone)
varies in age laterally

20. Time A: on the beach
(sandstone)
Sedimentary Facies & Sea Level
Stand in one spot
during a transgression:

21. Time B: underwater
(finer sediment)
Sedimentary Facies & Sea Level
Stand in one spot
during a transgression:

22. Regression:
• facies shift off-shore
Sedimentary Facies & Sea Level

23. Regression:
• facies shift off-shore
Sedimentary Facies & Sea Level
“the beach”
“the beach”
Time A Time B

24. Regression:
• in one place, facies become
more “onshore” (= coarser)
up section
Sedimentary Facies & Sea Level
Ls
Slt
Ss
fine
course

25. •In a vertical column,
facies become
progressively more
"on shore" (coarser)
up section.
Sedimentary Facies & Sea Level
Regression
Conglomerate
Sandstone
Siltstone
Limestone
erosion

26. •In a vertical column,
facies become
progressively more
"on shore" (coarser)
up section.
Sedimentary Facies & Sea Level
Regression
Conglomerate
Sandstone
Siltstone
Limestone
erosion
“deep”
“beach”
“land”

27. •In a vertical column,
facies become
progressively more
”off shore" (finer)
up section.
Sedimentary Facies & Sea Level
Transgression
Limestone
Siltstone
Sandstone
Conglomerate
erosion

28. •In a vertical column,
facies become
progressively more
”off shore" (finer)
up section.
Sedimentary Facies & Sea Level
Transgression
Limestone
Siltstone
Sandstone
Conglomerate
erosion
“deep”
“beach”
“land”

29. •A vertical sequence represents
facies that were once laterally
continuous
Sedimentary Facies & Sea Level
Walther’s Law
Limestone
Siltstone
Sandstone
vertical
sequence

30. •A vertical sequence represents
facies that were once laterally
continuous
Sedimentary Facies & Sea Level
Walther’s Law
Limestone
Siltstone
Sandstone
vertical
sequence
Lateral Distribution

31. Ls
Sh
Ss
•A vertical sequence
represents facies that
were once laterally
continuous
Walther’s Law

32. Ls
Sh
Ss
“deep”
“beach”
•A vertical sequence
represents facies that
were once laterally
continuous
Walther’s Law

33. •The relative sequence is more
important than absolute
completeness.
Sedimentary Facies & Sea Level
Walther’s Law
Limestone
Sandstone
vertical
sequence-1
Siltstone
vertical
sequence-2
unconformity

34. •The relative sequence is more
important than absolute
completeness.
Sedimentary Facies & Sea Level
Walther’s Law
Limestone
Sandstone
vertical
sequence-1
Siltstone
vertical
sequence-2
unconformity
Transgression Regression
“deep”
“beach”
“land”
“intermediate”

36. • Tectonic subsidence
(sinking)
• Rise in sea level
• Erosion of shore line
Sedimentary Facies & Sea Level
What cause a Transgression?

37. • Tectonic uplift
• Drop in sea level
• Over supply of sediment
Sedimentary Facies & Sea Level
What cause a Regression?

38. 1. Continental Glaciation
more ice = lower sea level
(max. 200 meter change)
Sedimentary Facies & Sea Level
Eustatic sea level change
(world wide)-causes?

39. http://www.shiftingbaselines.org/blog/archives/000430.html
1 meter rise

40. http://www.shiftingbaselines.org/blog/archives/000430.html
2 meter rise

41. http://www.shiftingbaselines.org/blog/archives/000430.html
6 meter rise

42. 30 meter rise

43. 100 meter rise
link to:USGS

44. 2. Plate Tectonics
fastspreading rate
= high sea level
slow= low sea level
(affects the shape of ocean basins)
Sedimentary Facies & Sea Level
Eustatic sea level change
(world wide)-causes?

45. • transgression in one place
while regression in another
• local mountain uplift
or crustal subsidence
• very rapid influx of sediment
or erosion.
Sedimentary Facies & Sea Level
Local sea level change