DRILLING ON ENIWETOK ATOLL, MARSHALL ISLANDS

摘要: Drilling on Eniwetok Atoll, Marshall Islands, revealed the presence of olivine basalt beneath shallow-water limestone Eocene age at a depth 4,154 feet. Two holes were put down opposite sides atoll: F-1 northwest where guyot (flat-topped seamount) adjoins atoll 700 fathoms, and E-1 southeast no is present. In F-1, hard basement rock was struck 4,610 feet, but sample recovered. hole E-1, unweathered cuttings obtained from feet solid core 4,208 to 4,222 Each penetrated several hundred soft, Quaternary reef before entering thick, Tertiary section similar rocks. The rocks are mostly limestones with minor amounts dolomite dolomitic limestone. Some made up clay-size silt-size particles carbonaceous. Most soft or weakly consolidated. two depths 1,400 feet; below this point there striking differences in lithologic characters, organic constitution, distribution cavities. drilling data indicate that thick cap resting summit volcano rises 2 miles above floor ocean.