The magneto-susceptibility event and cyclostratigraphy (MSEC) method used in geological correlation of Devonian rocks from Anti-Atlas Morocco

Magneto-Susceptibility Event and Cyclostratigraphy (MSEC) is used here as a means of establishing sensitive chronostratigraphic markers and chronohori zons useful for high-resolution correlation. MSEC is a composite of the mag netic susceptibility (MS) record of marine strata and the coeval biostratig raphic record and, similar to chronozones, zones based on MSEC data have bo undaries that are isochronous. MS, a measure of the concentration of magnet ic grains in sediments, proxies for the ratio of lithogenic to biogenic com ponents. Controls on the detrital input of lithogenic material include eust asy and climate, however induced, and sea floor/basin subsidence. The devel opment of an initial MSEC composite reference curve for the Middle-Upper De vonian of the Anti-Atlas region of southern Morocco is presented and discus sed in the context of global sea level transgressive and regressive cycles. MSEC trends, composed of increasing MS magnitudes, correlate well with epi sodes of regression, whereas trends of decreasing MS magnitudes correlate w ith episodes of transgression.