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ADMAP article from EOS

Development and Geologic Applications of the South Polar

Magnetic Anomaly Map

 

        International interest in the Antarctic is considerable because of the central role of its tectonics and geology in both Gondwana and Rodinia evolution, and the fact that it is the most poorly understood region of the planet.  Geologic studies of the Antarctic rely extensively on magnetic anomaly data because of the region's nearly ubiquitous ice cover. Consequently, numerous near-surface magnetic surveys have been carried out by the international community for site-specific geologic objectives.  However, with the first workshop of the Antarctic Digital Magnetic Anomaly Project (ADMAP) in Cambridge, UK, it also became clear that these limited-scale magnetic surveys may be combined into a regional magnetic synthesis which would further enhance their utility for geologic studies (Johnson et al., 1996; von Frese et al., 1996). Accordingly, ADMAP was launched in 1995 to compile and integrate into a digital database all existing near-surface and satellite magnetic anomaly data collected in Antarctica and surrounding oceans south of 60-degrees S. This multinational project is encouraged by resolutions of the Scientific Committee on Antarctic Research (SCAR) and the International Association of Geomagnetism and Aeronomy (IAGA).  A second ADMAP workshop (ADMAP II) was held at the Istituto Nazionale di Geofisica (ING) in Rome, Italy from 29 Sep. to 2 Oct. 97 to consider the progress and problems of this international effort.
        ADMAP II involved the participation of over 40 geoscientists from 8 countries with magnetic programs in the Antarctic.  The workshop featured 33 technical papers with the first scientific results produced under the ADMAP banner.  These presentations considered the geological analysis and interpretation of Antarctic aeromagnetic and marine magnetic anomalies and also reviewed the availability of these data sets for ADMAP.  Figure 1 shows the current track-line distribution of near-surface magnetic surveys from our updated catalog.
 

Figure 1

 
        Additional themes addressed by the technical presentations included procedures and software for compiling and analyzing polar magnetic survey data; problems in reducing near-surface magnetic surveys for Antarctic external and core field effects; use of satellite magnetic data for merging disparate near-surface magnetic surveys; and the status of efforts to compile complementary Antarctic gravity and radio echo sounding data. ADMAP II was also successful in tasking the Antarctic geoscience community  further for efforts and complementary data sets to enhance the geological utility of the Antarctic digital magnetic database.  This was done by establishing the following subcommittees:

1) GRAVITY DATA COMPILATION, chaired by Robin Bell (LDO), is working to compile gravity anomaly data into a digital database and anomaly map for the Antarctic south of 60-degrees S.

2) ROCK PHYSICAL PROPERTIES, chaired by Anne Grunow (BPRC), is working to compile rock magnetic and other physical properties into a database to support geological applications of Antarctic magnetic anomaly data.

3) MAPPING ADVISORY, chaired by Carol Finn (USGS), is coordinating compilation procedures, data formats, merging techniques, etc. for ADMAP.

4) MAGNETIC REFERENCE FIELD, chaired by Angelo De Santis (ING), is working to develop a more accurate Antarctic core field model for a variety of applications including better determination of crustal magnetic anomalies.

5) OPPORTUNITIES ADVISORY, chaired by Ralph von Frese (BPRC), is working to identify funding and other opportunities for proposals from ADMAP's Working Group.

        ADMAP II demonstrated that considerable progress has been made in achieving the objectives of the SCAR/IAGA Working Group in accordance with the protocols from ADMAP I (Johnson et al., 1997; von Frese et al., 1996).  Indeed, we are planning to have the major elements of the digital magnetic database completed by Spring '99.
        We hope to showcase these results at the ADMAP III workshop and the Spring '99 AGU meeting. ADMAP III will be held at the Byrd Polar Research Center of The Ohio State University just before the AGU meeting at which we also plan to have a session devoted to ADMAP's activities.
        A draft of the ADMAP II report should be available in Winter '98.  We plan to finalize it for public dissemination at the next meeting of the SCAR/IAGA Working Group at the Spring '98 AGU meeting in Boston (USA).  Publication of the proceedings of ADMAP II is also foreseen for a special issue of the journal ANNALI DI GEOFISICA.  Papers should be submitted to the guest editors, M. Chiappini and Ralph von Frese, by 15 Apr. 98. This publication is also open to ADMAP-related papers from those who could not attend ADMAP II. Instructions for authors as well as the workshop program are available from the ADMAP website at URL:

http:/io.ingrm.it/free/admp1.htm.

        For the book of abstracts and other information, contact Massimo Chiappini (Istituto Nazionale di Geofisica, Vigna Murata 605, 00143 Roma , I; TEL/FAX: +39-6-51860313/-5041181; E-MAIL: chiappini@marte.ingrm.it.  Further information on the activities of the Working Group may be also obtained from Ralph von Frese (Byrd Polar Research Center, The Ohio State University, Columbus, OH, USA; TEL/FAX: 01-614-292-5635/-7688; E-MAIL: vonfrese@osu.edu) or Peter Morris (Geoscience Division, British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 OET, UK; TEL/FAX: 44-1223-251574/- 362616; E-MAIL: pmor@bas.ac.uk).

REFERENCES CITED:

Johnson, A.C., von Frese R.R.B., and ADMAP Working Group, 1997, Magnetic map will define Antarctica’s structure,  EOS (Trans. Am. Geophys. Union), 78, 185.

von Frese, R.R.B., A.C. Johnson, and ADMAP Working Group, 1996, Report of the SCAR/IAGA Working Group on the Antarctic Digital Magnetic Anomaly Map, British Antarctic Survey Rept. & NSF Grant No. OPP-9527413 Rept.
 



        This report was contributed by Massimo CHIAPPINI, Ralph VON FRESE, John BEHRENDT, Robin BELL, Emanuele BOZZO, Giuliano BRANCOLINI, Detlef DAMASKE, Angelo DE SANTIS, Fausto FERRACCIOLI, Julie FERRIS, Carol A. FINN, Marta E. GHIDELLA, Alexander GOLYNSKY, Giovanni P. GREGORI, Anne GRUNOW, Takemi ISHIHARA, Chris JEWELL, Ash JOHNSON, John LABRECQUE, Emanuele LODOLO, Sergei MASCHENKOV, Antonio MELONI, Peter MORRIS, Yoshifumi NOGI, Michael PURUCKER, Patrick TAYLOR, and Miquel TORTA