46. Teagle, D.A.H., Wilson, D.S., Acton, G.D., and ODP Leg 206 Scientific Party, 2004. The "Road to the MoHole" four decades on: Deep Drilling at Site 1256. EOS, 85, 521, 530-531

Ocean Drilling Program (ODP) Hole 1256D, drilled 500 m into oceanic basement in the Guatemala Basin, is the first hole prepared with the infrastructure desirable for drilling a moderately deep hole into the oceanic basement (1.5-2 km).A second ocean drilling leg to this site should finish the recovery of the first complete section of upper oceanic crust from lavas down through the dikes into the uppermost gabbros.

Although Site 1256 has many advantageous features for a program to drill to the mantle, planning such an operation now would be premature, due in part to lack of engineering experience. In addition, there is significant scientific knowledge to be gained from drilling to depths of 1.3 km. Only through the characterization of the heterogeneity of the ocean crust by moderate-depth drilling at this and other sites will the essential information necessary to even choose a location for a full crustal penetration be acquired.The information learned on the “road to”selecting a MoHole site is at least as important as succeeding with that inspirational goal itself [see also Murray et al., 2002].

Keywords: review, ODP 206, Hole 1256, oceanic crust, mohole, ocean drilling

キーワード：国際深海掘削計画，第206次研究航海，1256孔，海洋地殻，モホール，深海底掘削