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4 New Developments GLOBAL GlDOSCI1:NCE TRANSECTS PROJECT As the transects of the North American Continent-Ocean Transects Program began to appear in print, it seemed clear to the USGC that the program was quite successful in terms of its intended goals. The USGC then strongly supported the recommendation that the International Lithosphere Program undertake an international program of transects across major geological/geophysical structures. The International Lithosphere Program is an ongoing, international program of studies of the solid earth, under the joint sponsorship of the International Union of Geodesy and Geophysics and the International Union of Geological Sciences. Guid- ance for the Lithosphere Program is provided by the Inter-Union Commission on the Lithosphere (ICL). The Inter-Union Commission on the Lithosphere approved a new program the Global Geoscience Transects (GOT) Project at its meeting in August 1985. The plan- ners of the GGT Project chew upon the experience of the North American Continent- Ocean Transects Program and requested assistance in specific matters. At the request of JCL, the USGC organized the preparation of a draft map of some 200 potential transects (prepared by Muawia Barazangi) and provided major assistance and support for organization and sponsorship of the Pilot Meeting on the GGT Project, held in San Francisco, 1~11 December 1985. Planning for the GGT Project moved rapidly. ICL established a Coordinating Committee for the GGT Project, headed by James Monger (Vancouver, Canada), one of the leaders of North American Transect B2 (Juan de Fuca Ridge to Alberta Plains). Monger spearheaded organizational meetings (see below) and plans for the GGT Project. The ICL recognizes the importance and inherent difficulty of combining the results obtained from geological investigations with geophysical data. The GGT project has thus stressed workshops and special meetings. In the period from 1986 to 1988, at least 20 workshops and meetings on GGT were held (national, regional or part of international gatherings). They include 2 in Africa, 5 in Asia and Australia, 6 in South America, 3 in North America, and 4 in Europe. Major guidelines were developed at 15
16 the GGT meetings during the General Assembly of TUGG, Vancouver, August 1987. Refinements were made at the ICL meetings during the Latin-American Geological Congress in Belem, Brazil, November 1988. The transects positioned to cross major crustal features range up to a few thousand kilometers in length and up to 100 km in width. Standardization of graphics (regarded an essential for the North American Continent-Ocea~ Transects Program) was adopted as a key principle of the GGT Project (with appropriate adaptations to accommodate a greater diversity of geological elements). The GGT displays wild have common formats, scales, and color schemes. As with the North American transects the GGT sections will extend at least to the base of the crust. In addition, GGT sections will also include detailed tectonic interpretations of Proterozoic and Archean crust (the North American transects encompassed only the Proterozoic). In general, the GGT will be based on existing data, but it is clear that newly acquired data will be needed for some of the most important transects in the GGT Project, especially in Antarctica. The GGT Project ~ guided by Coordinating Committee 7 of JCL. The project is divided into twelve regions, including the Arctic and Antarctic. By the end of 1988 168 transects had been proposed, in all 12 regions (Figure 3~. The North American sector is guided by a subgroup under the leadership of W.R. Van Schmus. Twelve transects have been accepted for the North American sector. This includes the Quebec-Mane transect (discussed below). This number does not include the recently initiated transcontinental transect along the Canadian-U.S. border and other transects in the formative stage. From the outset of GGT planning, it was agreed that the first major international presentation (symposia, poster sessions, and workshops) of results of the GGT Project from all parts of the world would take place in July 1989 at the 28th International Geological Congress, in Washington. The GGT sessions at the Geological Congress manifested remarkable progress in the project. DIGITAL DATA The USGC has a long-standing interest in the utilization of geological/geophysical data in digital and computer graphic form. The USGC recognizes that digitization of geoscience data is likely to become standard practice in the relatively near future. The USGC organized an ad hoc task group under the leadership of William Hinze to investigate this issue generally, with specific reference to the problems of digitizing the North American transects. A principal objective is to make the transects more useful In terms of changing scale and projections, viewing and analyzing the data in different ways, editing, and updating. In July 1986, that ad hoc task group recommended a two-track plan to digitize an existing North American transect (B2, Juan de Fuca Plate to Alberta Plains) and to develop a plan for digitizing the Quebec-Maine transect. The U.S. Geological Survey (in cooperation with the Geological Survey of Canada) implemented the first recommendation within a year and set in motion the implementation of the second. Both efforts involve the cooperation of U.S. and Canadian scientists. The Quebec- Ma~ne transect was under way prior to 1986 in a new generation of transects. It extends from the interior of Quebec, across Maine and into the Gulf of Maine; it is a joint undertaking of Canadian and U.S. groups under the coordination of David B. Stewart. In 1987, the Quebec-Maine transect was formally included in the GGT
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18 Project. The leaders of the Quebec-Maine transect agreed to prepare their results for publication following GGT guidelines. The Quebec-Maine transect is providing a de facto model for ways to use digitization in studying deep crustal and lithospheric structure. By the end of 1987, the importance of digitization for the GGT Project was well established: (1) to facilitate analysis of diverse types of data and reinterpretation (interpretation is never final); and (2) for storage of the immense amount of data. The ICL Coordinating Committees on Data Centers and Data Exchange (CC-5) and on GGT (CC-7) recommended that steps be taken to define the needs, problems, and appropriate actions regarding digitization of the GGT. A second meeting of the USGC Task Group on Digitization of Geological Data was held 19-20 May 1988 in cooperation with the two ICL Coordinating Committees (CC-5 and CC-7. That meeting dealt with many issues, including Tong-term preservation of GGT data and convenient availability for users. For example, CD-ROMs are favored for archiving large amounts of data. CD-ROMs have efficient and large storage capacity and long shelf life; they are cheap to duplicate; and their use involves relatively · . Inexpensive equipment. The need to plan for digitizing from the beginning of a transect project was emphasized by the USGC. The Quebec-Maine transect has provided pilot experience for digitizing transects. The task group recommended creation of advisory groups on digitization to assist CC-7 and the leaders of specific transects in the GGT Project. Steps are being taken by ACID to implement the recommendations of the task group. It is the stated intent of the GGT Project to develop digitization by example. For the North American sector of the GGT, a subgroup on digitization is being organized by W.R. Van Schmus. The leader of the subgroup is John Harbaugh; the group will include members from Canada, the United States, and other countries participating in the North American sector of the GGT. This subgroup will prepare practical guidelines for digitization of GGT projects ranging from those involving relatively simple data sets and digitizing capabilities to those involving more complex data sets and computer capabilities.
