Magnetostratigraphy of Leg 117 Sediments from the Owen Ridge and the Oman Margin, Western Arabian Sea

Abstract

Magnetic measurements were made on discrete samples from the Neogene pelagic and hemipelagic sediments recovered during ODP Leg 117. Polarity zones, usually identified for uppermost 200 m, were correlated to the geomagnetic polarity time scale referring to biostratigraphic datums. Quality and resolution of the magnetostratigraphy was partly limited by the weak and relatively soft magnetic character of almost all intervals, and core disturbance by gas expansion at some Oman Margin sites. Clear polarity records of the Brunhes and Matuyama chrons (Cl to C2r) were observed at Sites 724 and 727 on the Oman continental margin. Extended reversal records of the Pliocene were found at Site 722 on the Owen Ridge and Site 728 on the Oman Margin, and correlated to the Gauss to Gilbert chrons (C2A to C3).

350 ka Organic δ13C record of the monsoon variability on the Oman continental margin, Arabian Sea

“…Upper 32 m of the sediment cores collected at two sites (724C and 725C) during the Ocean Drilling Programme in the Arabian Sea (Leg 117) (figure 1) are used in this study. From the 18 O, magnetostratigraphy, and biostratigraphy (Hermelin 1991;Hayashinda and Bloemendal 1991;Zahn and Pedersen 1991) the analysed sediments are estimated to have been deposited over the past 350 ka.…”