International Lithosphere Program Research Articles

Stress measurements and tectonic implications for Fennoscandia

The main results from the Fennoscandian Rock Stress Data Base (FRSDB) are presented. Rock stress data from Sweden are now being selected to enter the data base of the World Stress Map Project of the International Lithosphere Programme. It is suggested that ridge push from the Mid-Atlantic Ridge is the major stress-generating mechanism. The scatter in stress magnitude and direction for Fennoscandia is due to the change in the stress field near faults. This is illustrated by means of simple 2-dimensional distinct element analyses of blocky rock masses subjected to a homogeneous far-field stress regime. Earthquakes are assumed to appear at fault intersections where stresses are concentrated.

The International Lithosphere Program

The International Lithosphere Program

Geosphere fluctuations and global change—Opening

This is an unusual conference. Here we are not mainly speaking to the experts of our own discipline. The common denominator of our presentations and discussions are processes in the solid earth related to temporal and spatial changes in a global scale and their interaction with other processes, possibly of different time scales in the spheres surrounding the lithosphere on which mankind is living. Welcome to this Alfred-Wegener-Conference on the Contribution of Solid Ear th Sciences to the IGBP. Welcome also in the name of the International Lithosphere Program. This conference is held at the request of the Bureau of the InterUnion Commission on the Lithosphere issued at Vancouver, August 1987. The Bureau felt tha t there is an urgent need for a better definition of the role of the solid earth sciences in the new International Geosphere-Biosphere Program, also known as the Global Change Program. To remind y o u t h e ICSU General Assembly in 1986 approved the IGBP-Global Change Program to start in the early 1990's. A special Committee for the IGBP was formed in 1987 comprising 13 members; it is charged with the preparation of the IGBP program at its start in early 1990's. The Special Committee has meanwhile formed 4 Coordinating Panels: 1. Terrestrial Biosphere-Atmospheric Chemistry Interactions (P.J. Crutzen) 2. Marine Biosphere-Atmosphere Interactions (T. Nemoto) 3. Biosphere Aspects of the Hydrological Cycle (S. Dyck) 4. Effects of Climate Change on Terrestrial Ecosystems (B.H. Walker) and 4 working Groups: 1. Global Geopshere-Biosphere Modelling (B. Bollin) 2. Data and Information Systems (S.I. Rasool) 3. Techniques for Extracting En vtronmental Data of the Past (H. Oeschger); now: Working Group on Global Changes of the Past. 4. Geo-Biosphere Observatories (R. Herrera) One important item in the discussion on the contribution of the solid earth sciences to IGBP is the question of the time scale of global changes to be investigated in IGBP. This discussion is gradually converging:

The Assembly of Pangea: Evolution of Laurussla . A Study in Late Palacozoic Plate Tectonics. Peter A. Ziegler. Published for the Royal Geological and Mining Society of The Netherlands by Kluwer, Norwell, MA, 1989. x, 102 pp., illus., + plates. $69. International Lithosphere Programme Designated Publication no. 0163

The Assembly of Pangea: <i>Evolution of Laurussla</i> . A Study in Late Palacozoic Plate Tectonics. Peter A. Ziegler. Published for the Royal Geological and Mining Society of The Netherlands by Kluwer, Norwell, MA, 1989. x, 102 pp., illus., + plates. $69. International Lithosphere Programme Designated Publication no. 0163

The Assembly of Pangea: Evolution of Laurussla . A Study in Late Palacozoic Plate Tectonics. Peter A. Ziegler. Published for the Royal Geological and Mining Society of The Netherlands by Kluwer, Norwell, MA, 1989. x, 102 pp., illus., + plates. $69. International Lithosphere Programme Designated Publication no. 0163

The Assembly of Pangea: <i>Evolution of Laurussla</i> . A Study in Late Palacozoic Plate Tectonics. Peter A. Ziegler. Published for the Royal Geological and Mining Society of The Netherlands by Kluwer, Norwell, MA, 1989. x, 102 pp., illus., + plates. $69. International Lithosphere Programme Designated Publication no. 0163

Evolution of Laurussla. A Study in Late Palacozoic Plate Tectonics. Peter A. Ziegler. Published for the Royal Geological and Mining Society of The Netherlands by Kluwer, Norwell, MA, 1989. x, 102 pp., illus., + plates. $69. International Lithosphere Programme Designated Publication no. 0163

Evolution of Laurussla. A Study in Late Palacozoic Plate Tectonics. Peter A. Ziegler. Published for the Royal Geological and Mining Society of The Netherlands by Kluwer, Norwell, MA, 1989. x, 102 pp., illus., + plates. $69. International Lithosphere Programme Designated Publication no. 0163

NATO granulite conference

On September 5–9, 1988, 83 participants from 20 different countries gathered in Clermont‐ Ferrand, France, for the workshop Petrology and Geochemistry of Granulites a nd Related Rocks. All geoscience disciplines were represented. The workshop was cosponsored by Universite Blaise Pascal, UFR Scientifique et Technique, Centre National de la Recherche Scientifique, International Lithosphere Program (working Group 2c), IGCP Project 235, Societe Francaise d e Mineralogie, Ministere de l'Education Nationale (DAGIC), Ministere des Affaires Etrangeres (DGSTD), Conseil Regional d Auvergne , Conseil General du Puy de Dome, Mairie de Clermont‐Ferrand.

The International Lithosphere Program Reviewed

The International Lithosphere Program Reviewed

Transect workshop held in Egypt

A workshop on the progress of the Global Geoscience Transects (GGT) project in the Middle East and Africa (see maps) was held January 15–17 in Cairo, Egypt. (Transect plans in the region have been described in Eos, 69, p. 124). It was jointly organized and funded by the Egyptian National Committee of Geodesy and Geophysics and the International Lithosphere Program coordinating Committee CC‐7 of GGT. A. Ashour of Cairo University, Egypt, chaired the workshop; the general secretary was S. Riad of Assiut University, Egypt, who was responsible for most of the organization, scheduling and implementation of the workshop.

Paleogeographic Reconstructions Using Interactive Three-Dimensional Computer Graphics: ABSTRACT

A computer program has been written (MEGADRIFTER) that permits users to interactively produce plate tectonic, paleoclimatic, and paleogeographic reconstructions. This program has been developed on an Evans and Sutherland PS390 and uses digital data compiled by the PALEOMAP Project, Working Group 2B, of the International Lithosphere Program. The digital data base consists of information describing a variety of geographic and geologic features, such as political boundaries, topography, bathymetry, faults, fracture zones, sutures, magnetic isochrons, volcanic edifices, lithofacies patterns, paleoisobars, and paleowind directions. MEGADRIFTER displays this geographic information in three dimensions on the surface of the globe. The user can produce plate tectonic reconstructions by interactively manipulating dials and function buttons to visually determine best-fitting rotation parameters. MEGADRIFTER is part of an integrated geographic information system that (1) digitally converts map data from Cartesian coordinates (X, Y) to geographic coordinates (latitude/longitude), (2) attaches meaningful attributes to the geographic records, (3) searches and sorts through the geographic attributes using a rudimentary geographic data base manager, and (4) plots the data in map form using standard cartographic techniques (GCTP).

Proterozoic Lithospheric Evolution

Recent years have seen significant new results on the evolution of Proterozoic terranes, and many of these resulted from new techniques, new concepts, and increasing multi‐disciplinary research. In 1981, Working Group (WG) 3 of the International Lithosphere Program (ILP) was established. Its principal tasks were clarification of the origin and evolution of the Proterozoic rocks and of the magmatic, metamorphic, deformational processes involved in their evolution; elucidation of the basic patterns of the structure and composition of the Proterozoic lithosphere and their implicatin for the geochemical differentiation of mantle and crust and the growth of continents; and characterization of Proterozoic tectonic regimes and evaluation of the role of plate tectonics in Proterozoic orogenesis and lithospheric evolution.

Global geoscience transects in the Arab region

The Global Geoscience Transects (GGT) project is one of the most recent initiatives of the International Lithosphere Program (ILP). The GGT project is represented by ILP Coordinating Committee 7 (CC7), which is coordinated by J . Monger (Geological Survey of Canada, Vancouver). M. Barazangi (Cornell University, Ithaca, N.Y.) is responsible for the coordination of the Middle East and North Africa region, which includes most of the Arab countries.The main objective of the GGT project is to strengthen and broaden international cooperation mainly through active participation of Earth scientists in constructing geological and geophysical transects, especially cross sections. The transects will be at least to Moho depth and will contain as much detail as transects of geological structures mapped on Earth's surface. The transects are being selected by the participating geoscientists to traverse all continents and, as much as possible, to form a continuous grid across political boundaries. Members of CC7 act as regional coordinators to help the local Earth scientists to initiate and implement GGT objectives. The implementation phase has to a large extent been standardized to follow clear guidelines that were developed by CC7 members. These guidelines are based on a modified and expanded version of the recent highly successful Continent‐Ocean Transect project of the Geological Society of America.

Mesozoic and Cenozoic Oceans

Marine sedimentary rocks now exposed on land are mainly deposits of shallow shelf seas, although ancient deep‐sea sediments do occur in the mountains. Thanks largely to the 15‐year effort by the Deep Sea Drilling Project of the Joint Oceanographic Institutions (JOI) Deep Earth Sampling Program, we have made quantum jumps in our understanding of the history of the ocean. Time has been added as the fourth dimension to oceanography, giving birth to a new interdisciplinary science, paleoceanography.The International Lithosphere Program is a successor to the International Geodynamics Program of the 1970s. The program is coordinated by the Inter‐Union Commission on Lithosphere (ICL), a commission of the International Council of Scientific Unions. This volume, Mesozoic and Cenozoic Oceans, is an interim report of Working Group 7 of the International Lithosphere Project.

Geoscientists will meet to organize transects project

The Global Geosciences Transects (GGT) project is a new activity of the International Lithosphere Program (ILP). The objective of GGT is to compile a series of 100 km‐wide crustal transects across major structures in all continents.The transects will be similar to those being produced by the North American Continent‐ Ocean Transects Program under the coordination of Robert C. Speed (Northwestern University, Evanston, 111.), except that they will include continental interiors and paleostructures (e.g., Precambrian sutures, rifts) as well as continental margins and active tectonic zones

Toward a federation of broadband seismic networks

Seismologists from many parts of the world are convinced that this is the time to undertake a major initiative in instrumenting the surface of the earth with a network of high‐quality modern seismographs. Realization of the compatibility of the efforts that arose nearly simultaneously in several countries led to a meeting in Karlsruhe, Federal Republic of Germany, April 10–11, 1986. The meeting was organized as part of a symposium of the International Lithosphere Program and was convened during the Annual Meeting of the German Geophysical Society. A proposal was made at the meeting to form an organization that would aid in the coordination of national programs by establishing common instrumentation standards and a mechanism for the timely exchange of data.

Continental Basalts and Mantle Xenoliths

In this decade of the International Lithosphere Program, much scientific attention is being directed toward the deep continental crust and subadjacent mantle. The petrologic, geochemical, and isotopic signatures of basaltic magmas, which transect much of the lithosphere as they ascend from their site of melting, and of contained cognate and accidental xenoliths, which are found along the path of ascent, give us, perhaps, the best clues to composition and structure in the third dimension. Continental Basalts and Mantle Xenoliths provides an opportunity to sample the British school of thought on subjects such as differences between oceanic and continental basalts, effects of mantle metasomatism, and relationships between events in the subcontinental mantle and those in the overlying crust. This volume is recommended by the publisher as being of interest to senior undergraduates and postgraduate researchers; I would extend that readership to all scientists who seek access to a potpourri of recent findings and current ideas in a rapidly evolving field of research.

The international lithosphere program

The International Lithosphere Program is a new international interdisciplinary research program in the solid earth sciences that has been established by the International Council of Scientific Unions (ICSU) at the joint request of the International Union of Geodesy and Geophysics (IUGG) and the International Union of Geological Sciences (IUGS). Its goal is a better understanding of the development of the earth, particularly those aspects upon which human society depends for its well‐being.The International Lithosphere Program (ILP) is a natural sequel to a series of international cooperative projects in the geosciences that began with the International Geophysical Year in 1957–58 and continued with the Upper Mantle Project in the 1960's and the International Geodynamics Project (IGP) in the 1970's. In 1977, IUGG and IUGS established an inter‐union task group to consider the possibility of a successor to the IGP for the 1980's. The task group, under cochairmen Carl Kisslinger (Cooperative Institute for Research in Environmental Sciences, University of Colorado), foreign secretary of the American Geophysical Union, and J. Henning Illies (Geophysical Institute, University of Karlsruhe, Federal Republic of Germany), invited suggestions and comments from the two unions and the national committees in the member countries. Their report, which was completed late in 1978, proposed a new project on the dynamics, origin, and evolution of the lithosphere. This proposal was approved by the IUGS Executive Committee in December 1979 and by the IUGS Council in June 1980. An inter‐union steering committee, established in 1979 under the joint chairmanship of Kisslinger and Illies, developed the organizational framework and constitution of the new program. These were approved by resolution of the ICSU Governing Board in September 1980, and the Inter‐Union Commission on the Lithosphere (ICL) was established to implement the program. National members of ICSU were urged to establish national committees and to develop internal programs for the new International Lithosphere Program.

Geodynamics—Where Are We and What Lies Ahead?

The introduction and evolution of the plate tectonics hypothesis during the past two decades has sparked the current renaissance of research in the earth sciences. An outgrowth of active geophysical and geological exploration of the oceans, the plate tectonics model has come under intense scrutiny by geologists, geochemists, and geophysicists who have attempted to apply the model to the origin and growth of continents, the generation of oceanic and continental crust, and the nature of the lithosphere, asthenosphere, and underlying mantle with respect to their evolution through time and to the driving mechanism or mechanisms for plate tectonics. The study of other terrestrial planets and moons has been helpful in understanding the earth model. The unequal distribution of geological features, both in the continents and oceans, emphasizes the need for ongoing studies of international scope such as the recently completed International Geodynamics Project and its successor, the International Lithosphere Program, both stressing studies related to the dynamics of the lithosphere.

International Lithosphere Program

A new program of international, interdisciplinary research in geodynamics was approved by the International Council of Scientific Unions at its meeting in Amsterdam in September 1980. The program, which is planned as a 10‐year effort, is a cooperative activity of the International Union of Geodesy and Geophysics (IUGG) and the International Union of Geological Sciences (IUGS). Management of the new program is the responsibility of a newly created Inter‐Union Commission on the Lithosphere.The research, to be carried out under the program entitled ‘Dynamics and Evolution of the Lithosphere: The Framework for Earth Resources and the Reduction of Hazards,’ will build on the remarkable accomplishments of the Upper‐Mantle Project and the International Geodynamics Project, which ended in 1979. The central theme of the program is the state, origin, evolution, and dynamics of the lithosphere, with special attention to the continents and their margins. The approved plan emphasizes that the program's goals can only be achieved by closely coordinated interdisciplinary efforts of geologists, geophysicists, geochemists, and geodesists. It is also clear that the desired improvement in our knowledge of the continental lithosphere requires additional work on key problems of the suboceanic lithosphere and of the structure, composition, and processes in the deeper parts of the earth.