Objectives for the Day General review seismic stratigraphy

Objectives for the Day • General review seismic stratigraphy exercises • Discussion of problems 3 and 4 • Begin working with Kingdom Tom Wilson, Department of Geology and Geography

Problems 3 and 4 from last week’s handout Tom Wilson, Department of Geology and Geography

Tom Wilson, Department of Geology and Geography

Island Platform, Deep Water, Southern Bahamas Tom Wilson, Department of Geology and Geography

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

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

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

National Petroleum Reserve, Alaska Sigmoid clinoforms Some questions to contemplate: 1) What was the bathymetric relief between the top and base of the prograding wedge? 2) Was the wedge building upward, outward, or a combination of the two? 3) What caused the reflectors on the left (4) to become hump shaped? Tom Wilson, Department of Geology and Geography

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

Let’s see how things stand with the Kingdom exercise. Tom Wilson, Department of Geology and Geography

Today • Hand in the initial seismic sequence interpretations • Be prepared to ask final questions on problems 3 and 4 next Monday. • Problems 3 and 4 due next Wednesday • Be prepared to show completed fault interpretation exercise or equivalent progress on your 3 D seismic interpretations next Monday. Tom Wilson, Department of Geology and Geography