1Ahmad Fauzi Nordin, 1Hassan Jamil, 1Mohd Noor Isa, 1Azhari Mohamed
2Sanudin Hj. Tahir, 2Baba Musta,
3Rene Forsberg, 3Arne Olesen, 3Emil Nielsen
4Abd Majid A Kadir, 4Ahmad Fahmi Abd Majid
5Kamaludin Talib, 5Saiful Aman Sulaiman
1Jabatan Ukur dan Pemetaan Malaysia, Jalan Semarak, 50578 Kuala Lumpur
2Faculty of Science and Natural Resources,Universiti Malaysia Sabah, 88400
3National Space Institute, Denmark Technical University, Copenhagen, Denmark
4Info-Geomatik, 81300 Skudai, Johor
5Faculty of Architecture, Planning and Surveying, Universiti Teknologi MARA
40450 Shah Alam, Selangor
ABSTRACT. Airborne gravimetry is an effective tool for mapping local gravity fields using a combination of airborne sensors, aircraft and positioning systems. It is suitable for gravity surveys over difficult terrains and areas mixed with land and ocean. This paper describes the geological mapping of Sabah using airborne gravity surveys. Airborne gravity data over land areas of Sabah has been combined with the marine airborne gravity data to provide a seamless land-to-sea gravity field coverage in order to produce the geological mapping. Free-air and Bouguer anomaly maps (density 2.67 g/cm3) have been derived from the airborne data both as simple ad-hoc plots (at aircraft altitude), and as final plots from the downward continued airborne data, processed as part of the geoids determination. Data are gridded at 0.025 degree spacing which is about 2.7 km and the data resolution of the filtered airborne gravity data were 5-6 km. The airborne gravity survey database for land and marine areas has been compiled using ArcGIS geodatabase format in order to produce the update geological map of Sabah.
KEYWORDS. Airborne gravimetry, gravity field, ArcGIS, geological mapping,
- Alberts, B.A., Ditmar, P., & Klees, R., 2007. A new methodology to process airborne gravimetry data: advances and problems. In: Tregoning P and Rizos C, (eds.). Proceedings of Dynamic Planet -Monitoring and Understanding a Dynamic Planet with Geodetic and Oceanographic Tools, volume 130 of IAG Symposia, pages 251–258, Cairns, Australia.
- Anderson, O., 2010. Global Gravity Field Model, Technical University of Denmark. www.space.dtu.dk
- Dwayne, B., 1986. Gravity Modeling of a Mafic-Ultramafic Association, Darvel Bay, Sabah, Northern Borneo. Department of Geology, Dalhousie University, Honours Bachelor of Science Degree Thesis (Unpublished).
- DTU, 2014. GRAVSOFT Package, National Space Institute (DTU-Space), Denmark Technical University, Copenhagen, Denmark.
- Forsberg, R., Olesen, A.V., & Keller, K., 1999. Airborne gravity survey of the North Greenland continental shelf. Technical Report 10, National Survey and Cadastre (KMS), Copenhagen, Denmark.
- Forsberg, R., 2002. Downward continuation of airborne gravity data. The 3rd meeting of the International Gravity and Geoid Commission ’Gravity and Geoid 2002’, Thessaloniki, Greece.
- Forsberg, R., 2010. Airborne Gravity Field Determination. Sciences of Geodesy I, Springer.
- Hofmann, W & Moritz, H., 2006. Physical Geodesy, Springer.
- Hutchinson, C.S., 1992. The Southeast Sulu Sea, a Neogene marginal basin with outcropping extensions in Sabah, Geol. Soc. Malaysia, Bulletin 32, November 1992; pp. 89 -108
- JUPEM, 2003. Airborne gravity survey and geoid determination project for Peninsular Malaysia, Sabah and Sarawak, Contract JUPEM-T04/2002, Final Report, Seksyen Geodesi, Bahagian Pemetaan.
- JUPEM, 2014. The Conduct of airborne gravity and magnetic survey over selected area near the international maritime boundary offshore of Sabah and Sarawak, Phase I (2014), Contract JUPEM-T03/2013, Final Report, Bahagian Ukur Geodetik.
- JUPEM, 2015. The Conduct of airborne gravity and magnetic survey over selected area near the international maritime boundary offshore of Sabah and Sarawak, Phase II (2015), Contract JUPEM-T-24/204, Final Report, Bahagian Ukur Geodetik.
- Olesen, A.V., 2003. Improved airborne scalar vector gravimetry regional gravity field mapping and geoid determination. Technical report, National Survey and Cadastre (KMS), Copenhagen, Denmark.
- Olesen, A.V. & Forsberg, R., 2007. Airborne scalar gravimetry for regional gravity field mapping and geoid determination. In: Harita Dergisi, Proceedings of the 1st International Symposium of the International Gravity Field Service ’Gravity field of the Earth’, pages 277–282, Istanbul, Turkey.
- Sanudin Hj. Tahir & Baba Musta., 2007. Pengenalan kepada Stratigrafi (Introduction to Stratighraphy). Universiti Malaysia Sabah, Kota Kinabalu.
- Sanudin, T., Baba Musta, & Ismail, A.R., 2010. Geological heritage features of Tawau volcanic sequence, Sabah. Bulletin of the Geological Society of Malaysia 56, pp. 79 – 85
- Yin, E. H., 1985. Geological Map of Sabah, East Malaysia. 3rd Edition, Geological Suryey of Malaysia.