The OCTek project uses a new gravity inversion technique to produce maps and grids of crustal thickness and continental-lithosphere thinning factor at rifted continental margins and their ocean-continent transitions (OCT). The maps of crustal thickness are restored, via a new set of plate reconstructions, to their geometry at the time of breakup, immediately prior to ocean-basin formation.
Key to the new gravity inversion technique is the incorporation into the inversion scheme of:
• The lithosphere thermal gravity anomaly resulting from breakup, which at the time of breakup is a very strong negative anomaly, relaxing slowly with time
• Prediction of new volcanic crustal addition during breakup, leading to ocean crust formation, using the melt parameterization models of our former iSIMM colleague Prof Bob White (White & McKenzie 1989, JGR; Bown & White 1994, EPSL).
Published results have shown the importance of incorporating both these parameters in the inversion when investigating deepwater margins.
OCTek works with public-domain gravity, bathymetry and sediment thickness data to produce maps and grids of:
• Depth to Moho
• Total crustal thickness
• Residual continental-crustal thickness
• Crustal thinning factor and beta factor
• Residual thermal gravity anomaly
Confidential commercial studies can also be undertaken using proprietary sediment thickness data.
OCTek thinning factor maps can be used to build new maps of top basement heat-flow history. Each OCTek report includes a small software executable file which, with minimal user input, will convert thinning factor maps to maps of top basement heat-flow, both at the present-day and step-by-step back through time to breakup.
Six studies are currently available:
• Arctic / North Atlantic
• Indian Ocean
• GoM & Caribbean
We are currently working on: