171B Scientific Prospectus

Site: BN-5Alt

Priority: 1

Position: 29°57.090'N, 76°37.596'W

Water depth: 1293 m

Sediment thickness: >3000 m

Seismic coverage: Gloria Farnella 1987 SCS Line 20, TD5UW (shotpoint 1241) (see seismic profile).

Objectives: Determine history of Paleogene and Cretaceous water chemistry, carbonate productivity, and deep-water and surface temperature as well as evolutionary history of pelagic microfossils. Core Paleocene-Eocene and Cretaceous-Paleogene boundaries for paleoceanographic, evolutionary, and stratigraphic studies. Shallow end-member of depth transect. May be deepened by up to 200 m if time permits to recover an expanded Aptian-Albian section.

Drilling program: 1. APC coring to 160 mbsf or refusal (oriented): Hole A.
2. Holes B and C cored to 160 mbsf or refusal by unoriented APC.
3. Holes A and B deepened by XCB to 450 mbsf. XCB drilling of Hole B may be abandoned depending upon results of Hole A.

Logging and downhole operations: Standard strings (triple-combo geophysical and FMS) and GHMT (magnetic susceptibility). Adara and WSTP temperature measurements may be run if time permits. Core orientation on at least the A hole.

Nature of rock anticipated: Nannofossil-foraminifer ooze, chalk, cherty limestone, calcareous clay.

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