Predicting OCT Location and Continental Extension for North Atlantic Rifted Margins Using Gravity Inversion
Gravity inversion incorporating a lithosphere thermal gravity anomaly correction has been used to determine Moho depth, crustal basement thickness and lithosphere thinning factor for ~50 2D regional profiles across North Atlantic rifted margins including Labrador Sea, Baffin Bay, Iberian - Newfoundland and Norwegian - Greenland conjugate margins. Sediment thickness derived from seismic refraction/reflection data has been included in the gravity inversion: sediment density is assumed to be compaction controlled. Gravity inversion has been used to estimate the location of the ocean-continent transition (OCT) and to determine lithosphere extension across the rifted margins. The lithosphere thermal model used to predict the lithosphere thermal gravity anomaly correction may be conditioned using plate reconstruction models to provide the age and location of oceanic lithosphere. OCT locations predicted by plate reconstruction models may be unreliable as a consequence a gravity inversion method has been used in which the lithosphere thermal model used to predict the lithosphere thermal gravity anomaly correction assuming that the entire region is continental lithosphere with a constant breakup age applicable to the margin being investigated. A correction to the predicted thinning factor from gravity inversion is made for the addition of continental volcanic material produced by decompression melting during breakup, lithosphere thinning and seafloor spreading. This method, in which isochrons are not used, provides an independent check for the location of the OCT. Comparing crustal thickness obtained from the gravity inversion with seismic estimates allows us to constrain the age of continental breakup. Lithosphere extension estimates across the margins can be used to refine plate reconstruction models.
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- 8105 Continental margins: divergent (1212;
- 8150 Plate boundary: general (3040);
- 9325 Atlantic Ocean