plates. Here, measurements of in situ fluid pressures showed that the oceanic sediments in the lower plate are overpressured. Cores from sedimentary strata of the upper plate showed strong evidence of tectonic kneading of sediments in the accretionary prism and also the presence of fluid escape channels carrying waters squeezed from the deforming sediments upward to the seafloor.
Several transects across the entire active margin complex (trench, forearc, volcanic arc, backarc basin, and remnant arc) have documented not only the materials in this system, but the timing and rates of development in them as well as the contrasting deformational styles in zones with thickly sedimented compared to near-barren trenches.
Now the drilling program is approaching another crossroads. In 2003, unless something new happens, drilling may well cease or be replaced by a quite different program strongly resembling OMD in its scientific objectives. Planning continues for the five-year ODP time between now and then.
One drilling prospect has been opened by the Japanese announcement that they intend to construct, at their own expense, a large ship ("Godzilla Maru") fitted out for riser drilling. Some tens of millions of dollars are said to be in the pipeline for design studies for a ship that will cost upwards of $500 million to build and have daily operating costs of something like $130,000 (about three times the JOIDES Resolution). Drilling from this ship during the first few years is planned to be in waters not more than about 2.5 km deep (shallower than most of the spreading ridge system, let alone the main ocean floor), and the ship would work for much of this time close to Japanese home waters, where a number of problems in the structure, hydrology, and seismicity of thickly sedimented active margins are available. Proposals for specific riser drilling objectives are now being formulated.
As for nonriser, ODP-style drilling, NSF is said to be looking at the possibilities of funding a Resolution-type vessel for operations post-2003, in addition to paying its share of the Japanese riser ship daily costs. The U.S. COMPOST-II Committee on Post-2003 Scientific Ocean Drilling issued a report in 1996 endorsing a two-ship program. The active scientific community is busy writing proposals to be discussed at a planned international conference in 1999. Urgent messages are in the air that we should all be demonstrating support for and submitting proposals for work in an Integrated Ocean Drilling Program (IODP) to follow ODP, and using two ships, riser and nonriser. We appear still to lack concordance on major new scientific initiatives, initiatives of the scope and imagination of the original Mohole project, initiatives that can capture the attention of large segments of not only the scientific community but the public and Congress as well. To arms! Enlist now!
I thank Bruce Malfait for the data on year-by-year expenditures for drilling projects. Both he and Walter Munk made constructive suggestions on an early draft of the paper. D.K. Van Keuren kindly allowed use of his unpublished paper on the history of the Mohole Project. W.W. Hay made constructive suggestions for improvement of an earlier draft of the manuscript.
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