Do drifts deposited adjacent to carbonate platforms record the signal of global carbon isotopic values?. Issue 4 (18th March 2019) - Swart, Peter K.
Abstract: This study investigates the δ 13 C values of Middle Miocene–Modern drift deposits and periplatform sediments in the Maldives and compares these data with the global δ 13 C values derived from bulk oceanic sediments and foraminifera. This comparison reveals that while the δ 13 C values of the early Miocene periplatform sediments in the Maldives appear to track the global record of δ 13 C values, including increases associated with the Oligocene–Miocene boundary as well as the variations within the Monterey Event, the correlation with the Monterey Event may be coincidental. It is suggested that variations in δ 13 C values do not reflect changes in oceanic dissolved inorganic carbon, but instead pulses of sediment arising from platform progradation that contribute carbonates with elevated δ 13 C values derived from the adjacent shallow‐water atolls. This conclusion is supported both by correlations between the seismic sequence architecture and the δ 13 C values which document progradation of 13 C‐rich platform sediments, and also by the continuation of the interval of 13 C‐rich sediments past the end of the Monterey Event at 13 Ma within the drift.