1. General review seismic stratigraphy exercises
Objectives for the Day
General review seismic stratigraphy exercises
Lithic surfaces versus reflection events
Edge enhancement and detection
Some additional conceptual diagrams illustrating deposition under cycles of eustatic sea level rise and fall
The Woodbine play
Synthetic tie
Identifying the sequence and internal reflection patterns associated with the Woodbine
The influence of processing
Construction the chronostratigraphic chart
Tom Wilson, Department of Geology and Geography
Tom Wilson, Department of Geology and Geography

2. Island Platform, Deep Water, Southern Bahamas
Platform to the left. Appears simple with wedge of sediments dipping down to the right which is in turn onlapped by flatter lying sediments 1)
Tom Wilson, Department of Geology and Geography

3. some comments on the preceding section
In the preceding section, the platform lies to the left. The prominent seismic sequence to the right appears as a simple wedge of sediments dipping down to the right which is in turn onlapped by flatter lying sediments.
Closer inspection reveals several distinct intervals of onlap belonging to at least three different sequences.
The section reveals an earlier prograding sequence that was extensively eroded and itself followed by additional onlap against the escarpment to the left.
Subtle downlap and onlap mark locations of smaller sequences within the latest package that extends to the water bottom.
The pattern suggests presence of an earlier high stand system followed by significant sea level drop and then by gradual and relatively steady sea level rise
Tom Wilson, Department of Geology and Geography

4. Prograding clinoforms/oblique
Baltimore Canyon, East Coast, US
Prograding clinoforms/oblique
Erosional Truncation
A combination of prograding clinoforms followed by sealevel drop and coastal onlap (3 and above) overlie a thick sequence characterized by predominantly parallel reflection events with some local onlap (1) above a deeper erosional inconformity
Tom Wilson, Department of Geology and Geography

5. National Petroleum Reserve, Alaska
Sigmoid clinoforms
Tom Wilson, Department of Geology and Geography

6. National Petroleum Reserve, Alaska
Sigmoid clinoforms
Some questions to contemplate:
What was the bathymetric relief between the top and base of the prograding wedge?
Was the wedge building upward, outward, or a combination of the two?
What caused the reflectors on the left (4) to become hump shaped?
Tom Wilson, Department of Geology and Geography

7. Prograding clastic wedge
Central Atlantic Shelf, near the Baltimore Canyon
Prograding clastic wedge
The reflectors to the right of 1) build both out and up. The internal configuration is oblique (left) to sigmoid (near 1) and then oblique again. The environment is prograding shelf margin.
Tom Wilson, Department of Geology and Geography

8. Splay, Floodplain, & Channel Environments
F37 Event
Manual pick of the F37 Lithic surface
Flattened on the F37 reflection event
Tom Wilson, Department of Geology and Geography

9. Splay, Floodplain, & Channel Environments
The F37 “stratal” time surface
Hardage et al. (1994)
Tom Wilson, Department of Geology and Geography

10. Tom Wilson, Department of Geology and Geography

11. "Edge" Detection Processing
Enhancing Discontinuities to Resolve Depositional and Structural Features
"Edge" Detection Processing
Results from an analysis of coherency between events in the seismic data set
Bahorich and Farmer, 1995
Tom Wilson, Department of Geology and Geography

12. Schlumberger’s Ant Tracking Process
Tom Wilson, Department of Geology and Geography

13. General background on the Woodbine
Upper Cretaceous shoreline deposits
USGS Fact Sheet
Tom Wilson, Department of Geology and Geography

14. Sea Level Rise and Fall Posamentier and Vail, 1985
Tom Wilson, Department of Geology and Geography

15. Identifying the Woodbine reflection events using a synthetic seismic tie
Dynamite source
Tom Wilson, Department of Geology and Geography

16. Synthetic Seismogram The Ogletree #1 Reflection coefficient train
sonic
No 
impedance
composite - +
Austin Chalk
Eagleford Shale
Top of the Woodbine
Buda Limestone
Tom Wilson, Department of Geology and Geography

17. Seismic Response of the Woodbine
Austin
Eagle Fd.
Woodbine
Buda
Ogletree #1
Stricklin, 2007
Tom Wilson, Department of Geology and Geography

18. Identifying the Woodbine Sequence
Tom Wilson, Department of Geology and Geography

19. The Woodbine Seismic Sequence1 2 3 4 5
Where do intervals 1 through 5 fall on the relative depositional time scale?
Tom Wilson, Department of Geology and Geography

20. Tom Wilson, Department of Geology and Geography

21. http://homepage. ufp. pt/biblioteca/GlossarySaltTectonics/Pages/PageD
Tom Wilson, Department of Geology and Geography

22. Stratigraphic (Depth)
Seis Strat Exercise
Stratigraphic (Depth)
Chronostratigraphic
Tom Wilson, Department of Geology and Geography

23. Start working on the Woodbine sequence and hand in next Wednesday
Seis Strat Exercise
Start working on the Woodbine sequence and hand in next Wednesday
Tom Wilson, Department of Geology and Geography

24. Newer processing flow. Better or worse?
The influence of processing on the interpretation. 1970s versus 1997 – which is better?
Older 1970s processing
Newer processing flow. Better or worse?
Talk about diffractions
Tom Wilson, Department of Geology and Geography

25. Migration before or after
Migration after stacking
Migration before stacking provides a slightly better view of internal prograding intervals
Tom Wilson, Department of Geology and Geography

26. What you see is not necessarily what you get
post-stack migration
Basic lesson is that processing flow can influence what you see in your section and thus your geologic interpretation
pre-stack migration
Tom Wilson, Department of Geology and Geography

27. Seismic Stratigraphy Exercise1 2 3 4 5
Identify internal subdivisions. Use lapout and truncation relationships to establish subdivisions.
Consider the relationship between sediment supply and sea level rise during deposition of these sediment packages.
Tom Wilson, Department of Geology and Geography

28. Global sea level curves from Vail and Mitchum
Seis Strat Exercise
Chronostratigraphic Section ?
87 Mya ? 3 4
89 Mya
91 Mya 2
93 Mya 1
95 Mya 5
97 Mya 1 2 3 4 5
Global sea level curves from Vail and Mitchum
Tom Wilson, Department of Geology and Geography

29. To do Hand in the initial seismic sequence interpretations.
Complete the construction of the chronostratigraphic chart and hand in …..
Tom Wilson, Department of Geology and Geography
Tom Wilson, Department of Geology and Geography