Antarctic Digital Magnetic Anomaly Project (ADMAP)

Convenor: Marta Ghidella

Background:

The ADMAP multinational project was created in 1995 under the auspices of SCAR and IAGA (International Association of Geomagnetism and Aeronomy).

The latest results of ADMAP have been the publication of a map and the production of special issues of the scientific journals Annali di Geofisica (Advances in Antarctic Geomagnetism, Vol. 42, 1999) and Tectonophysics (Magnetic Anomalies of the Antarctic, Vol. 347, 2002) with related papers. The map, in digital form, as well as the corresponding grid, are available from the Internet at www.geology.ohio-state.edu/geophys/admap.

The ADMAP group now intends to become an Expert Group with the major objective of maintaining the data base and making it a permanent tool availabe to the scientific community.

Terms of reference:

The magnetic anomaly field of the Earth’s crust is of fundamental importance for understanding geological processes. Considering that numerous magnetic surveys have been carried out by various institutions, the ADMAP group aims to produce a coordinated effort for:

• Compiling the existing magnetic data acquired by various institutions
• Coordinating protocols for data distribution
• Serve as a reference for future survey planning
• Archiving and maintaining the magnetic anomaly data base of Antarctica

Work plan:

a) Short term

Production of a CD-ROM of the ADMAP grids and related surveys for release to the public through the World Data Centers. The CD will include the magnetic line data, metadata, and the already released grid, as well as documentation and graphical guidelines for survey location. This will be finished and released to the World Data Centers before June 2005.

Completing this objective requires roughly a month of dedicated effort by one or two Expert Group members and the meeting of the full Expert Group. The meeting is necessary to endorse the CD’s release to the World Data Centers (WCDs) and renew ADMAP’s protocols for maintaining and updating the database. The meeting is also necessary to plan ADMAP’s contributions for the International Polar Year. In addition, new initiatives for the Group members will be considered, including the recent effort by the Italian, US, and other national Antarctic programs to launch the next generation of ADMAP. Since 2002, the Working Group has expended considerable time and effort on this ongoing initiative that will allow ADMAP to serve Antarctic geomagnetic studies into the IPY and beyond.

b) Longer term

1. Implementation of ADMAP’s protocols to maintain and update the database with new airborne and shipborne magnetic survey data and related metadata as they become available.

2. Updating the near-surface anomaly predictions from Magsat in the ADMAP database with the significantly more accurate observations from the Ørsted and CHAMP satellite missions. In the longer run, it is also considered to incorporate magnetic gradient measurements that will become available towards the end of the current decade from ESA’s recently authorized multi-satellite SWARM mission. These observations will greatly improve crustal anomaly detail at satellite altitudes since one of the mission’s main objectives is to model the polar external fields.

3. Development of improved modeling of the Antarctic core field and its secular variations, and external fields for better definition of the crustal anomalies in magnetic survey data.

4. Compilation of rock magnetic and other physical properties into a database to support geological applications of the ADMAP data.

5. Development and promoting regional and continental scale interpretation efforts of the ADMAP data. This will provide new insight into global tectonic and geologic processes in the Antarctic context. New data and interpretations will also enhance studies addressing interplays between geological boundary conditions, Antarctic ice sheets and climate change. Finally, these efforts will also greatly assist in identifying high-priority areas for new collaborative magnetic surveys.

6. Expanding collaborative efforts with Arctic working groups for more bi-polar magnetic exploration and research.

7. Providing a broad collaborative framework for new frontiers in the magnetic exploration of the polar regions, such as by long-range aircraft and UAVs.

The list of current ADMAP members is at the Geosicence SSG web site, www.geoscience.scar.org/admap/