Site summaries (continued)

Site SCS-4C

Priority: Primary for backup operations plan
Position: 12°59.033′N, 115°9.40′E
Water depth (m): 4380
Target drilling depth (mbsf): 789
Approved maximum penetration: Approved to basement + 100 m (Estimated total depth = 789 mbsf)
Survey coverage (track map; seismic profile): Bathymetric sketch and site track map (Fig. AF23, AF27) Deep-penetration seismic reflection:
• Primary line: 973SCSIO_2b (SP4575) (Fig. AF28)
• Crossing line: A3B6 (SP7489) (Fig. AF29)
Objectives: Alternate for SCS-4B
• Determine the age of the Southwest Sub-basin
• Test the hypothesis that the Southwest Sub-basin evolved within continental crust by rifting
• Measure magnetization, mineralization, and geochemical compositions of basement rocks
• Examine the paleoceanographic response to the opening of the South China Sea
Drilling program: Hole A:
• APC to refusal with nonmagnetic core barrels, core orientation (FlexIT tool), and APCT-3
• XCB to refusal
• Drop FFF
• RCB with nonmagnetic core barrels to 789 mbsf
Downhole logging program: • Triple combo
• FMS-sonic
Nature of rock anticipated: (Calcareous) mudstone, siltstone, sandstone, basalt