Rock Magnetic Properties during the Paleocene-Eocene Thermal Maximum (PETM): Records from P/E boundary Sections (Sinjar, Shaqlawa) in Iraq

Abstract

Rock magnetic properties have been investigated across the Paleocene/Eoceneboundary in two distally separate sections of Paleogene marine sedimentary rocksfrom Iraq, namely the Sinjar and the Shaqlawa sections. The sediments at thestudied sections belong to the Aaliji and the Kolosh formations respectively, whichwere previously examined for their biostratigraphy by the authors using planktonicand benthonic foraminifera to delineate the Paleocene/Eocene (P/E) transition.Measured magnetic properties include; bulk magnetic susceptibility, hysteresiscycles, isothermal remnant magnetization (IRM) acquisition, and thermomagneticcurves analysis. Rock-magnetic results (i.e. low magnetic coercivity component)indicate greigite as the main magnetic phase at Aaliji rocks, while a mixture ofmagnetite and greigite with high magnetic coercivity has been observed at Koloshclastics. Magnetic susceptibility is induced by related to both biogenic minerals(mainly at Aaliji Formation) and transported terrigenous material sources. Multivaried magnitude phases of high bulk rock magnetic susceptibility observed inboth formations along PETM lithosomes are attributed to two sources: greigite orbiogenic iron oxides source and increase in terrigenous discharge source asinferred by anoxic to suboxic iron - sulfate-reducing conditions and lithologicalchange respectively. Both sources referred to some of environmental conditionsassociated with Paleocene - Eocene thermal maximum events such as methanedissociation, water stratification, enhanced hydrological and weathering cycles.