Sedimentary Facies & Sea Level

1. Sedimentary Facies & Sea Level Sedimentary Facies and Sea Level Changes

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

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

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

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

6. Sedimentary Facies & Sea Level sandstone facies shale facies

7. Sedimentary Facies & Sea Level Two types of facies 1). Lithofacies: can be degree of difference

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

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

10. Sedimentary Facies & Sea Level Mississippi Delta Foraminifera facies

11. Sedimentary Facies & Sea Level Changes in sea level

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

42. 30 meter rise

43. 100 meter rise link to: USGS

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

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