tific observers have played a distinctive role in marine geology, geophysics, and geochemistry. The remotely operated vehicle represents a capability as yet largely unproven.
The Ocean Drilling Program and its predecessors have contributed as much as any facility to the rapid development of the solid-earth sciences over the past 25 years. The current program is planned through 1998. A recent NRC review of the program recognizes the scientific value of continued ocean drilling and recommends broadening participation, ensuring breadth in future activities, and focusing on the establishment of "a highly accurate geochronologic framework for studies of past ocean processes and rates as well as for an optimum approach to drilling technology."
The development and use of advanced instruments are critical to the solid-earth sciences. The need for such instrumentation and facilities extends to every one of the priority themes developed in this report. Specialized needs have been defined throughout the report in tables and in the text. A 1990 report by the NRC Board on Earth Sciences and Resources, Facilities for Earth Materials Research, addressed community needs by identifying two distinct levels of implementation: one ("Schedule A") incorporates initiatives justified by present technology, manpower, and demand, and the other ("Schedule B") defines a minimum level below which research on some topics cannot be carried out at an internationally competitive level. This approach is potentially useful to those involved in implementing recommendations, and a similar approach might be extended to other areas treated in this report.
Advanced instruments for chemical and isotopic analyses of the compositions of naturally occurring solids, liquids, and gases are all needed. The earth sciences have particular requirements for determining compositions at small sites within materials (e.g., at several places in a microscopically zoned crystal), as well as compositions of tiny particles (e.g., stratospheric dust from volcanoes). Modern beam instruments are well adapted for these purposes, and future developments are likely.
Access to accelerator and synchrotron facilities will be increasingly important as their capabilities for analytical purposes become better developed and more widely appreciated in the solid-earth science community. These issues are thoroughly discussed in the Facilities for Earth Materials Research report, but it is clear that implementation of the recommendations of the present report could have implications for the way in which facilities are used. For example, increased emphasis on the geology of the past 2.5-million-years, which is recommended in this report, requires more dating by cosmogenic nuclide measurement. Developments of this kind could put a strain on existing facilities for accelerator mass spectroscopy.
Equipment for very-high-pressure experimentation will be extremely valuable. The ability to generate in the laboratory pressures and conditions as great as those obtained at the center of the Earth has been a significant development in the past decade. The need for the coming decade is to conduct a range of experiments that fully exploit the new capabilities represented by such instruments as diamond cells and to use those capabilities together with other forms of advanced instrumentation.
Large-volume, high-pressure instrumentation also is necessary. The ability to simulate conditions of the deepest crust and upper mantle in "large" volumes (greater than about 1 mm3), which has been developed only in the past decade, opens up the opportunities for expanded experimental activity.
There is a growing need in the solid-earth sciences for advanced organic chemical and isotopic analyses. The study of organic geochemistry has been stimulated by such diverse interests as working out the origin and evolution of petroleum and understanding the preservation of ancient DNA. The importance of organic composition and structure in interpreting ancient environments, both at the surface and after burial, is a field that is developing fast enough for it to be singled out from among other laboratory instrumentation and facility considerations.
The most striking progress in the solid-earth sciences may be in the development and use of data bases. Arrays of large and diverse sets of basic research data are important for all research areas, including modern maps representing three-dimensional data bases collating geological, geophysical, geochemical, geochronological, geotechnical, and geobiological data. The data accrue too rapidly for convenient storage in hard copy, and geographic information systems must be brought into widespread use for display and analysis of these data. For much research, access to data on material and thermodynamic properties, reaction kinetics, and the