6:15 PM - 7:30 PM
[MIS32-P09] Vitrinite reflectance of carbonaceous materials in cuttings retrieved during the IODP Expedition 348
Keywords:vitrinite reflectance, carbonaceous matter, paleotemperature, accretionary prism
To evaluate whole thermal structure of the Site C0002, we performed vitrinite reflectance analysis for cuttings samples collected every 100 m of Holes C0002N and C0002P. Vitrinite reflectance (Ro) is an indicator to estimate maximum paleotemperature, which has been widely applied to reveal tectonic evolution of on-land accretionary complex (e.g. Underwood et al., 1992; Sakaguchi, 1996; Ohomori et al., 1997) and thermal anomalies along fault slip zones reflecting frictional heating due to seismic slip (e.g. Sakaguchi et al., 2007; Sakaguchi et al., 2011). This is the first study that applied vitrinite analyses systematically to the entire modern accretionary prisms.
In this presentation, we report preliminary results of vitrinite reflectance analysis. Ro values are 0.15 to 0.20 in Unit III (forearc basin strata), 0.20 to 0.27 in Unit IV (accretionary prism strata), and 0.20 to 0.45 in Unit V (hemipelagic sediment). In general, Ro values tend to be gradually and continuously increasing with depth. Estimated paleotemperatures of Unit IV and V are approximately 40℃ and 90℃, respectively, which are consistent with estimated modern temperatures (Sugihara et al., 2014).