The role of pre-break-up heat flow on the thermal history of a transform margin
Published:January 01, 2016
M. Nemčok, A. Henk, M. Molčan, 2016. "The role of pre-break-up heat flow on the thermal history of a transform margin", Transform Margins: Development, Controls and Petroleum Systems, M. Nemčok, S. Rybár, S. T. Sinha, S. A. Hermeston, L. Ledvényiová
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The paper focuses on the Romanche transform margin on the African side of the Equatorial Atlantic, and draws from thermomechanical numerical modelling and subsequent GIS-based thermal history grid processing.
Our modelling indicates that the early post-break-up thermal history of the transform margin is controlled by the cooling patterns of the adjacent pull-apart terrains, the pre-rift heat-flow regime, laterally passing seafloor spreading centres, and cooling of the newly accreted oceanic crust in two corridors located in front of and behind the spreading centres.
The pre-rift thermal regime controls the background heat flow on top of which the thermal transients develop. If it is cold, the transient anomalies are very distinct on this background. If it is warm, the transient anomalies tend to blend in with background heat flow much better. The most prominent anomalies are related to thinning in the pull-apart terrains located between transforms. They are up to three times wider than anomalies related to the laterally passing spreading centre, the anomaly of which becomes no wider than 20–25 km. Together with oceanic crust accreted in corridors in front of and behind the passing centre, its heat transfer into the transform margin tends to slow down the cooling of the syn-break-up anomalies developed in the pull-apart terrains by rifting.
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Transform Margins: Development, Controls and Petroleum Systems
This volume covers the linkage between new transform margin research and increasing transform margin exploration. It offers a critical set of predictive tools via an understanding of the mechanisms involved in the development of play concept elements at transform margins. It ties petroleum systems knowledge to the input coming from research focused on dynamic development, kinematic development, structural architecture and thermal regimes, together with their controlling factors. The volume does this by drawing from geophysical data (bathymetry, seismic, gravity and magnetic studies), structural geology, sedimentology, geochemistry, plate reconstruction and thermo-mechanical numerical modelling. It combines case studies (covering the Andaman Sea, Arctic, Coromandal, Guyana, Romanche, St. Paul and Suriname transform margins, the French Guyana hyper-oblique margin, the transtensional margin between the Caribbean and North American plates, and the Davie transform margin and its neighbour transform margins) with theoretical studies.