Proceedings of the
Ocean Drilling Program

Volume 163
Scientific Results
SOUTHEAST GREENLAND MARGIN

Covering Leg 163 of the cruises of the Drilling Vessel JOIDES Resolution
Reykjavik, Iceland, to Halifax, Nova Scotia
Sites 988-990
3 September-7 October 1995

SHIPBOARD SCIENTISTS
Hans-Christian Larsen, Robert A. Duncan, James F. Allan,
Yoshiaki Aita, Nicholas T. Arndt, Christian J. Bücker, Hervé Cambray, Katharine V. Cashman, Brian P. Cerney, Peter D. Clift, J. Godfrey Fitton, Bernard Le Gall, Peter R. Hooper, Stephen D. Hurst, Lawrence A. Krissek, Kristen E. Kudless, Lotte M. Larsen, Charles E. Lesher, Yukari Nakasa, Yaoling Niu, Harald Philipp, Sverre Planke, Jakub Rehacek, Andrew D. Saunders, Damon A.H. Teagle, Christian Tegner

SHIPBOARD STAFF SCIENTIST
James F. Allan

EDITORIAL REVIEW BOARD
Hans-Christian Larsen, Robert A. Duncan, James F. Allan, Kent Brooks

VOLUME EDITOR
John Scroggs

Citations

Reference to the whole or to part of this volume should be made as follows:

WWW volume citation:

Larsen, H.C., Duncan, R.A., Allan, J.F., Brooks, K. (Eds.), 1999. Proc. ODP, Sci. Results, 163 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/163_SR/163TOC.HTM>. [Cited YYYY-MM-DD]

WWW chapter citation (PDF):
Planke, S., and Alvestad, E., 1999. Seismic volcanostratigraphy of the extrusive breakup complexes in the northeast Atlantic: implications from ODP/DSDP drilling. In Larsen, H.C., Duncan, R.A., Allan, J.F., Brooks, K. (Eds.), Proc. ODP, Sci. Results, 163, 3-16 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/163_SR/VOLUME/CHAPTERS/CHAP_01.PDF>. [Cited YYYY-MM-DD]

WWW chapter citation (HTML):
Planke, S., and Alvestad, E., 1999. Seismic volcanostratigraphy of the extrusive breakup complexes in the northeast Atlantic: implications from ODP/DSDP drilling. In Larsen, H.C., Duncan, R.A., Allan, J.F., Brooks, K. (Eds.), Proc. ODP, Sci. Results, 163, 3-16 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/163_SR/chap_01/chap_01.htm>. [Cited YYYY-MM-DD]

Print citation:

Larsen, H.C., Duncan, R.A., Allan, J.F., Brooks, K. (Eds.), 1999. Proc. ODP, Sci. Results, 163: College Station, TX (Ocean Drilling Program).

Planke, S., and Alvestad, E., 1999. Seismic volcanostratigraphy of the extrusive breakup complexes in the northeast Atlantic: implications from ODP/DSDP drilling. In Larsen, H.C., Duncan, R.A., Allan, J.F., Brooks, K. (Eds.), Proc. ODP, Sci. Results, 163: College Station, TX (Ocean Drilling Program), 3-16.

CD-ROM citation:

Larsen, H.C., Duncan, R.A., Allan, J.F., Brooks, K. (Eds.), 1999. Proc. ODP, Sci. Results, 163 [CD-ROM]. Available from: Ocean Drilling Program, Texas A&M University, College Station, TX 77845-9547, U.S.A.

Planke, S., and Alvestad, E., 1999. Seismic volcanostratigraphy of the extrusive breakup complexes in the northeast Atlantic: implications from ODP/DSDP drilling. In Larsen, H.C., Duncan, R.A., Allan, J.F., Brooks, K. (Eds.), Proc. ODP, Sci. Results, 163, 3-16 [CD-ROM]. Available from: Ocean Drilling Program, Texas A&M University, College Station, TX 77845-9547, U.S.A.

ISSN
Printed book: 0884-5891; CD-ROM volume: 1096-2514; WWW volume: 1096-7451
Library of Congress 87-642-462

Effective publication dates of ODP Proceedings

According to the International Code of Zoological Nomenclature, the date of publication of a work and of a contained name or statement affecting nomenclature is the date on which the publication was mailed to subscribers, placed on sale, or when the whole edition is distributed free of charge, mailed to institutions and individuals to whom free copies are distributed. The mailing date, not the printing date, is the correct one.

The printing date of this volume: August 1999

The mailing dates of recent Proceedings of the Ocean Drilling Program:
Volumes 174A/174AX/174B (Initial Reports): November 1998
Volume 175 (Initial Reports): November 1998
Volume 177 (Initial Reports): April 1999
Volumes 159/159T (Scientific Results): October 1998
Volume 160 (Scientific Results): September 1998
Volume 161 (Scientific Results): February 1999

Copies of this publication may be obtained from Publications Distribution Center, Ocean Drilling Program, Texas A&M University, 1000 Discovery Drive, College Station, TX 77845-9547, U.S.A. See the ODP publication list at www-odp.tamu.edu/publications or contact ODP for prices and ordering information. Orders for copies require advance payment.

Publisher’s Notes

This publication was prepared by the Ocean Drilling Program, Texas A&M University, as an account of work performed under the international Ocean Drilling Program, which is managed by Joint Oceanographic Institutions, Inc., under contract with the National Science Foundation. Funding for the program was provided by the following agencies at the time of this cruise:

Australia/Canada/Chinese Taipei/Korea Consortium for Ocean Drilling: Department of Primary Industries and Energy (Australia), Natural Resources Canada (Canada), National Taiwan University in Taipei, and Korean Institute for Geology, Mining and Minerals

Deutsche Forschungsgemeinschaft (Federal Republic of Germany)

European Science Foundation Consortium for Ocean Drilling (Belgium, Denmark, Finland, Iceland, Italy, The Netherlands, Norway, Portugal, Spain, Sweden,  and Switzerland)

Institut Français de Recherche pour l’Exploitation de la Mer (France)

National Science Foundation (United States)

Natural Environment Research Council (United Kingdom)

University of Tokyo, Ocean Research Institute (Japan)

Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation, the participating agencies, Joint Oceanographic Institutions, Inc., Texas A&M University, or Texas A&M Research Foundation.

Abbreviations for names of organizations and publications in ODP reference lists follow the style given in Chemical Abstracts Service Source Index (published by American Chemical Society).

The bulk of the shipboard-collected data from this leg is available on the World Wide Web and is accessible at www-odp.tamu.edu/database. If you cannot access this site or need additional data, please contact the ODP Data Librarian, Ocean Drilling Program, Texas A&M University, College Station, TX 77845-9547, U.S.A. (e-mail: database@odpemail.tamu.edu).

Supplemental data on the volume CD-ROM were provided by the authors and may not conform to ODP publication formats.

A site map showing the drilling locations for this leg and maps showing the drilling locations of all Ocean Drilling Program (ODP) and Deep Sea Drilling Project (DSDP) drilling sites are available on the volume CD in PDF format.

Beginning with Initial Reports Volume 176 and Scientific Results Volume 169, all Proceedings volumes will be published on CD-ROM and the World Wide Web at www-odp.tamu.edu/publications.

E-mail addresses may be updated. Send requests to pub_production@odpemail.tamu.edu.

Cover photograph from the deck of the JOIDES Resolution by Roy Davis.

Foreword
By the National Science Foundation

The National Science Foundation is proud to play a leading role in partnership with the U.S. oceanographic community in the operation and management of the Ocean Drilling Program (ODP). We are equally proud of the cooperation and commitment of our international partners, who contribute both financial and intellectual resources required to maintain the high quality of this unique program. The Ocean Drilling Program, like its predecessor, the Deep Sea Drilling Project (DSDP), is a model for the organization and planning of research to address global scientific problems that are of high priority internationally and of long-term interest to the scientific community and general public.

Major scientific themes guiding the development of specific drilling cruises range from determining the causes and effects of oceanic and climatic variability to understanding the circulation of fluids in the ocean crust and the resultant formation of mineral deposits. Although such studies are at the forefront of basic scientific inquiry into the processes that control and modify the global environment, they are equally important in providing the background for assessing man’s impact on the global environment or for projecting resource availability for future generations.

The transition from the DSDP to the ODP was marked by a number of changes. The 471-foot JOIDES Resolution, which replaced the Glomar Challenger, has allowed larger scientific parties and the participation of more graduate students, a larger laboratory and technical capability, and operations in more hostile ocean regions. The JOIDES Resolution has drilled in all of the world’s oceans, from the marginal ice regions of the Arctic to within sight of the Antarctic continent. Over 1,200 scientists and students from 26 nations have participated on project cruises. Cores recovered from the cruises and stored in ODP repositories in the United States and Europe have provided samples to an additional 1,000 scientists for longer term postcruise research investigations. The downhole geochemical and geophysical logging program, unsurpassed in either academia or industry, is providing remarkable new data with which to study the Earth.

In 1994, NSF and our international partners renewed our commitment to the program for its final phase. Of the 20 countries that supported ODP initially, only one, Russia, has been unable to continue for financial reasons. As the reputation and scientific impact of the program continue to grow internationally, we hope to add additional members and new scientific constituencies. This global scientific participation continues to assure the program’s scientific excellence by focusing and integrating the combined scientific knowledge and capabilities of its member nations.

We wish the program smooth sailing and good drilling!

Neal Lane
Director
National Science Foundation
Arlington, Virginia

Foreword
By Joint Oceanographic Institutions, Inc.

This volume presents scientific and engineering results from the Ocean Drilling Program (ODP). The papers presented here address the scientific and technical goals of the program, which include providing a global description of geological and geophysical structures including passive and active margins and sediment history, and studying in detail areas of major geophysical activity such as mid-ocean ridges and the associated hydrothermal circulations.

The Ocean Drilling Program, an international activity, operates a specially equipped deep-sea drilling ship, the JOIDES Resolution, which contains state-of-the-art laboratories, equipment, and computers. The ship is 471 feet (144 meters) long, is 70 feet (21 meters) wide, and has a displacement of 18,600 short tons. Her derrick towers 211 feet (64 meters) above the waterline, and a computer-controlled dynamic-positioning system stabilizes the ship over a specific location while drilling in water depths up to 27,000 feet (8230 meters). The drilling system collects cores from beneath the seafloor with a derrick and drawworks that can handle 30,000 feet (9144 meters) of drill pipe. More than 12,000 square feet (1115 square meters) of space distributed throughout the ship is devoted to scientific laboratories and equipment. The ship sails with a scientific and technical crew of 51 and a ship’s crew (including the drill crew) of 62. The size and ice-strengthening of the ship allow drilling in high seas and ice-infested areas as well as permit a large group of multidisciplinary scientists to interact as part of the scientific party.

Logging, or measurements in the drilled holes, is an important part of the program. ODP provides a full suite of geochemical and geophysical measurements for every hole deeper than 1300 feet (400 meters). For each such hole, there are lowerings of basic oil-industry tools: nuclear, sonic, and electrical. In addition, a Formation MicroScanner is available for high-resolution imaging the wall of the hole, a 12-channel logging tool provides accurate velocity and elastic property measurements as well as sonic waveforms for spectral analysis of energy propagation near the wall of the hole, and a vertical seismic profiler can record reflectors from below the total depth of the hole.

The management of the Ocean Drilling Program involves a partnership of scientists and governments. International oversight and coordination are provided by the ODP Council, a governmental consultative body of the partner countries, which is chaired by a representative from the United States National Science Foundation (NSF). The ODP Council periodically reviews the general progress of the program and discusses financial plans and other management issues. Overall scientific and management guidance is provided to the operators of the program by representatives from the group of institutions involved in the program, called the Joint Oceanographic Institutions for Deep Earth Sampling (JOIDES).

The Executive Committee (EXCOM), made up of the administrative heads of the JOIDES institutions, provides general oversight for ODP. The Science Committee (SCICOM), with its advisory structure, is made up of working scientists and provides scientific advice and detailed planning for the Ocean Drilling Program. SCICOM has a network of panels and committees that screen drilling proposals, evaluate instrumentation and measurement techniques, and assess geophysical survey data and other safety and siting information. SCICOM uses the recommendations of the panels and committees to select drilling targets, to specify the location and major scientific objectives of each two-month drilling segment or leg, and to provide the science operator with nominations for co-chief scientists.

Joint Oceanographic Institutions, Inc. (JOI), a nonprofit consortium of U.S. oceanographic institutions, serves as the National Science Foundation’s prime contractor for ODP. JOI is responsible for seeing that the scientific objectives, plans, and recommendations of the JOIDES committees are translated into scientific operations consistent with scientific advice and budgetary constraints. JOI subcontracts the operations of the program to two universities: Texas A&M University and Lamont-Doherty Earth Observatory of Columbia University. JOI is also responsible for managing the U.S. contribution to ODP under a separate cooperative agreement with NSF.

Texas A&M University (TAMU) serves as science operator for ODP. In this capacity, TAMU is responsible for planning the specific ship operations, actual drilling schedules, and final scientific rosters, which are developed in close cooperation with SCICOM and the relevant panels. The science operator also ensures that adequate scientific analyses are performed on the cores by maintaining the shipboard scientific laboratories and computers and by providing logistical and technical support for shipboard scientific teams. Onshore, TAMU manages scientific activities after each leg, is curator for the cores, distributes samples, and coordinates the editing and publication of scientific results.

Lamont-Doherty Earth Observatory (LDEO) of Columbia University is responsible for the program’s logging operation, including processing the data and providing assistance to scientists for data analysis. The ODP Data Bank, a repository for geophysical data, is also managed by LDEO.

Core samples from ODP and the previous Deep Sea Drilling Project are stored for future investigation at four sites: ODP Pacific and Indian Ocean cores at TAMU, DSDP Pacific and Indian Ocean cores at the Scripps Institution of Oceanography, ODP and DSDP Atlantic and Antarctic cores through Leg 150 at LDEO, and ODP Atlantic and Antarctic cores since Leg 151 at the University of Bremen, Federal Republic of Germany.

Scientific achievements of ODP include new information on early seafloor spreading and how continents separate and the margins evolve. The oldest Pacific crust has been drilled and sampled. We have new insights into glacial cycles and the fluctuations of ocean currents throughout geological time. ODP has also provided valuable data that shed light on fluid pathways through the lithosphere, global climate change both in the Arctic and near the equator, past sea-level change, seafloor mineralization, the complex tectonic evolution of oceanic crust, and the evolution of passive continental margins.

Many of the scientific goals can be met only with new technology; thus the program has focused on engineering as well as science. To date, ODP engineers have demonstrated the capability to drill on bare rock at mid-ocean-ridge sites and have developed techniques for drilling in high-temperature and corrosive regions typical of hydrothermal vent areas. A new diamond coring system promises better core recovery in difficult areas. In a close collaborative effort between ODP engineers and scientists, a system has been developed that seals selected boreholes ("CORKs") and monitors downhole temperature, pressure, and fluid composition for up to three years. When possible, ODP is also taking advantage of industry techniques such as logging while drilling, to obtain continuous downhole information in difficult-to-drill formations.

JOI is pleased to have been able to play a facilitating role in the Ocean Drilling Program and its cooperative activities, and we are looking forward to many new, exciting results in the future.

James D. Watkins
Admiral, U.S. Navy (Retired)
President
Joint Oceanographic Institutions, Inc.
Washington, D.C.

Preface

The Scientific Results volumes of the Proceedings of the Ocean Drilling Program contain specialty papers presenting the results of extensive research in various aspects of scientific ocean drilling. The authors of the papers published in this volume have enabled future investigators to gain ready access to the results of their research, and I acknowledge their contributions with thanks.

Each paper submitted to a Scientific Results volume undergoes rigorous peer review by at least two specialists in the author’s research field. A paper typically goes through at least one revision cycle before being accepted for publication. We seek to maintain a peer-review system comparable to those of the most highly regarded journals in the geological sciences.

Each Scientific Results volume has an Editorial Review Board that is responsible for obtaining peer reviews of papers submitted to the volume. This board usually is made up of the two co-chief scientists for the cruise, the ODP staff scientist for the cruise, and one external specialist who is familiar with the geology of the area investigated. In addition, the volume has an ODP staff editor who assists with manuscripts that require English-language attention and who coordinates volume assembly.

Scientific Results volumes may also contain short reports of useful data that are not ready for final interpretation. Papers of this type are called Data Reports and include no interpretation of results. Data Report papers are read carefully by at least one specialist to make sure they are well organized, comprehensive, and discuss the techniques or procedures thoroughly.

To acknowledge the contributions made by this volume’s Editorial Review Board, the Board members are designated Editors of the volume and are so listed on the title page. Reviewers of manuscripts for this volume, whose efforts are so essential to the success of the publication, are listed in the front of the book, without attribution to a particular manuscript.

On behalf of the Ocean Drilling Program, I extend sincere appreciation to members of the Editorial Review Boards and to the reviewers for giving their generous contribution of time and effort, which ensures that only papers of high scientific quality are published in the Proceedings.

Paul J. Fox
Director
Ocean Drilling Program
Texas A&M University
College Station, Texas

Reviewers for this Volume

Ocean Drilling Program*

*At time of publication. See Publisher’s Notes, for list of funding agencies at time of cruise. For an up-to-date list of current member organizations and office contact information, see the ODP Web site: www.oceandrilling.org.

National Science Foundation
4201 Wilson Boulevard
Arlington, VA 22230, U.S.A.
Tel: (703) 306-1581; Fax: (703) 306-0390
Web site: www.nsf.gov

Member Organizations of the Joint Oceanographic Institutions for Deep Earth Sampling (JOIDES)

University of California at San Diego, Scripps Institution of Oceanography

Columbia University, Lamont-Doherty Earth Observatory

University of Hawaii, School of Ocean and Earth Science and Technology

University of Miami, Rosenstiel School of Marine and Atmospheric Science

Oregon State University, College of Oceanic and Atmospheric Sciences

University of Rhode Island, Graduate School of Oceanography

Texas A&M University, College of Geosciences

University of Texas at Austin, Institute for Geophysics

University of Washington, College of Ocean and Fishery Sciences

Woods Hole Oceanographic Institution

Australia/Canada/Chinese Taipei/Korea Consortium for Ocean Drilling: Department of Primary Industries and Energy (Australia), Department of Energy, Mines and Resources (Canada), National Taiwan University in Taipei, and Korean Institute for Geology, Mining and Minerals

European Science Foundation Consortium for Ocean Drilling (Belgium, Denmark, Finland, Iceland, Italy, The Netherlands, Norway, Portugal, Spain, Sweden, and Switzerland)

Federal Republic of Germany, Bundesanstalt für Geowissenschaften und Rohstoffe

France, Institut Français de Recherche pour l’Exploitation de la Mer

Japan, University of Tokyo, Ocean Research Institute

People’s Republic of China, Marine High-Technology Bureau of the State Science and Technology Commission of the People’s Republic of China

United Kingdom, Natural Environment Research Council

Ocean Drilling Program (ODP)
Web site: www.oceandrilling.org

Leg 163 Participants*

*Mailing addresses at time of cruise.

Shipboard Scientific Party

ODP Publications Staff^*

*At time of publication.
†Lead staff members for this volume.