HR: 1340h
AN: GP23A-0022    [Abstracts]
TI: Magnetic Anomaly Modeling in the Bay of Bengal
AU: * Rajaram, M
EM: mita@iigs.iigm.res.in
AF: Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai, 410218 India
AU: Anand, S
EM: anand@iigs.iigm.res.in
AF: Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai, 410218 India
AB: The thick sediment deposits carried by the several rivers in India, into the Bay of Bengal mask the underlying crust and pose severe restrictions in mapping the structural configuration and constructing the geodynamical history of the Bay of Bengal. In addition to this, the subduction zone around the Andaman and Sumatran region causes the oceanic lithosphere to be under stress, resulting in intense deformation. Geopotential data offer the unique opportunity of resolving some of these issues. Satellite derived free air gravity data, marine magnetic data, available seismic profiles and isopach maps over the Bay of Bengal are utilized in the present paper. Seismic profiles in the Indian offshore together with the isopach map of the region are utilized to constrain the model parameters for reproducing the satellite derived free air gravity anomalies over a profile along 11 degrees N latitude from the east coast of India up to the Andaman region. This helps determine the configuration of the 85 degrees East Ridge. Using thickness parameters derived from this gravity model as a constrain, an attempt is made to model the NGDC marine magnetic data along this long profile of around 1100 km length, by incorporating remanent magnetization in addition to the induced field. The magnetic profile along 11 degrees N is very well reproduced when the strike angle of the spreading anomalies matched the value obtained by the Scientists of the National Institute of Oceanography, India. However, we find that only three reversals are required to be incorporated into the model, with the 85E Ridge being reversely magnetised. A similar process of modeling is applied to the second profile along 10 degrees North latitude. Along the two-modeled profiles, the magnetic characteristics of the sea floor to the east of 85 E ridge are similar but they show different characteristic to the west. The results of these models will be interpreted in terms of the Sea floor spreading of the region.
DE: 1517 Magnetic anomalies: modeling and interpretation
DE: 1550 Spatial variations attributed to seafloor spreading (3005)
DE: 3005 Marine magnetics and paleomagnetics (1550)
DE: 3010 Gravity and isostasy (1218, 1222)
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
SC: Geomagnetism and Paleomagnetism [GP]
MN: Fall Meeting 2005