Thermal regime if the rifted continental margin and its tectonic implication
Presenter: Shin-Ting Ding Advisers: Wu-Lung Chang, Tien-Shun Lin
Abstract
We use a simple approach to estimate the present-day thermal regime of continental margins, offshore Pakistan and offshore southwest Taiwan. A complication of bottom boreholes temperatures and thermal gradients derived from new observations of bottom-simulating reflections (BSRs) allows us to constrain the relationship between the thermal regime and the known tectonic and sedimentary framework along the margin. There is marked difference in thermal gradients and heat flow beneath the shelf and slope region. In the margin of offshore Pakistan, we calculate the potential radiogenic contribution to the surface heat flow along a profile across the margin. Measurements across the continental shelf show intermediate thermal gradient of 38-44 oC/km. the onshore Indus Basin shows a lower range of values spanning 18-31 oC/km. the Indus Fan slope and continental rise show an increasing gradient from 37-55 oC/km. In the margin of offshore southwest Taiwan, it is cooler beneath the shelf with an average thermal gradient of 34.5 oC/km, and 62.7 mW/m2 heat flow. The continental slope shows a higher average thermal gradient of 56.4 oC/km, and 70.9 mW/m2 heat flow.
References
G. Calvès et al., 2010. Thermal regime of the northwest Indian rifted margin- comparison with predictions. Mar. Pet. Geol. 27, 1133-1147.
Lin, W.-Z. et al., 2014. Heat flow in the rifted continental margin of the South Chain Sea near Taiwan and its tectonic implications. J. Asian Earth Sci. 92, 233-244.