Abstract Magnetic susceptibility (MS) measurements of marine rocks provide an underutilized but powerful high-resolution tool in stratigraphy. In ideal circumstances and when combined with other stratigraphic techniques, the method can yield resolution to 10,000 years or less. This paper applies the MS method to solving a Cretaceous global correlation problem. Because of the active global processes that drove significant evolutionary changes during this time, the Upper Cretaceous is important in Earth history. However, correlations among geological sequences are difficult, in part because Earth’s magnetic polarity was essentially non-varying from the Aptian to the Santonian. Here we present high-resolution correlations for Upper Cretaceous marine sedimentary successions spanning all or part of the Santonian Stage from the Western Interior Seaway (U.S.A.) and the Western Sinai Peninsula (Egypt). To do this we have integrated the results of magnetic susceptibility (MS) measurements of unoriented samples from lithified marine rocks (in outcrop and from core) and biostratigraphic data sets from these sequences. In this study a MS zonation for the Santonian Stage has been developed and graphic comparison has been used for correlation. In the main, correlation between the U.S. and Egyptian sequences is excellent. Third order T/ R cycles (> 100 kyr) observed in this high-resolution data set for the Santonian Stage indicate significant similarities between the U.S. and Egyptian sections and allow correlation among sequences. We interpret these correlations to result from cyclicities caused by climate-controlled continental erosion and deposition of detrital components, mainly clay, in the marine realm. Second-order cycles (> 1 Myr) are also observed in these data sets but show distinctive differences between the U.S. and Egyptian sequences. We interpret these second-order differences to result from local synsedimentary tectonic controls on sediment erosion and deposition. Also observed are two distinct, short-term MS marker events that can be correlated globally. Application of Modern Stratigraphic Techniques: Theory and Case Histories SEPM Special Publication No. 94, Copyright © 2010 SEPM (Society for Sedimentary Geology), ISBN 978-1-56576-199-5, p. 155–166.

Abstract The magnetostratigraphy susceptibility technique is used to establish high-resolution correlation among Paleocene–Eocene boundary sequences in Egypt, Spain, and the U.S.A. This work initially focuses on the Global boundary Stratotype Section and Point (GSSP), defining the base of the Ypresian Stage (lowest Eocene), located in the Dababiya Quarry near Luxor in Upper Egypt. The base of the Eocene represents the beginning of the Paleocene–Eocene Thermal Maximum (PETM) identified by a negative carbon isotope (δ 13 C) excursion. While onset of the CIE is somewhat gradual in most reported Paleocene–Eocene (P–E) sections, at the GSSP it is very abrupt and begins immediately after an unusual lithologic change that magnetic susceptibility (MS) and other data indicate represents a short erosional or nondepositional hiatus. Comparison of MS zones from five well-studied marine sequences (the Dababiya Quarry GSSP, Jebal El Qreiya, also in Upper Egypt, Zumaia in northern Spain, Alamedilla in southern Spain, and the MGS-1 Harrell Core from southeastern Mississippi, U.S.A.) with that from the GSSP site shows a period of reduced sedimentation and nondeposition through the boundary interval in the GSSP. This interval, estimated to have lasted for ~ 10,000 years, is less than the biostratigraphic resolution for the site. Due to the hiatus in the GSSP, we have chosen the P–E section in Zumaia as the MS reference section for the P–E boundary interval. Because the correlation between the Zumaia section in Spain and the MGS-1 Core from the U.S.A. is excellent, and because the MGS-1 data set represents a longer interval of time than does the Zumaia data set, we use the MS data from the MGS-1 Core to extend the MS zones from Zumaia and establish a MS composite reference section (MS CRS) for the P–E boundary interval sampled. Orbital-forcing frequencies for the Zumaia reference section are then identified, via spectral analysis. Extending the MS zones into the MS CRS allows age assignment to MS zones for all five sections with a resolution of ~ 26,000 years. Application of Modern Stratigraphic Techniques: Theory and Case Histories SEPM Special Publication No. 94, Copyright © 2010 SEPM (Society for Sedimentary Geology), ISBN 978-1-56576-199-5, p. 167–179.