Print this pageMagnetostratigraphy Susceptibility: A Useful High-Resolution Correlation Tool in Stratigraphy
Brooks Ellwood1, Aziz Kafafy2, Ahmed Kassab3, Abdelaziz Abdeldayem2, and Paul Sikora4
1 Louisiana State University, Baton Rouge, LA
2 Tanta Universty, Egypt
3 Assiut University, Egypt
4 Energy and Geoscience Institute, Salt Lake City, UT
Magnetic susceptibility (MS) measurements of unoriented samples from lithified marine rocks are being used, in conjunction with biostratigraphic data sets, for high resolution correlation among stratigraphic sequences; in outcrop, from core and using cuttings. Because there exist abundant, in-depth biostratigraphic studies on sections being considered for classification as Global boundary Stratotype Sections and Points (GSSPs), we have concentrated on GSSPs and other well correlated sequences, to build composite sections (CS) for MS correlations. The example we report here is for the Upper Cretaceous, Santonian Stage. Stratigraphic sections spanning all or part of the Santonian stage from Egypt and the US are correlated. These sections include one of the proposed Santonian/Campanian GSSPs, that from Waxahachie, Texas, the USGS#1 Portland Core, Colorado, and composited Niobrara chalk sections from Kansas. These sequences all have fair to good biostratigraphic control. The results demonstrate that correlation between a US CS, composed of the Niobrara composite and the proposed GSSP, and the Lower to Middle Santonian interval recovered from the USGS#1 core is excellent. In the main, correlation between the US CS and MS data from the Sinai in Egypt is also excellent.