[HCG23-P06] Estimation of the sea floor events by radiocarbon dating of total organic carbon contained in marine sediment
Keywords:hemipelagic mud, radiocarbon dating, total organic carbon , event layer
Omura et al. (2016, Geol. Soc. Japan Abstract) measured radiocarbon dating of TOC (14 CTOC) ages of a short core (60 cm) obtained off Kumano, succeeded in discriminating flood sediments, seismo-turbidites and hemipelagic mud originated from the Kumano river. Therefore, we would like to verify that continuous measurement of 14CTOC can be applied to older sequences. Also, our research aims to establish an estimation method of depositional event (e.g. earthquake or flood) to clarify the exact age of the event which have not known so far.
We measured the 14CTOC contained in hemipelagic and turbidite layers by using Accelerator Mass Spectrometry (AMS) to investigate the depositional age of event deposits such as turbidites which can be detected by X-ray CT scanner. The results show age reversals in the turbidite layers suggesting sediment reworking and contamination of old organic carbon although age reversals were also observed in a few sequences where turbidites cannot be recognized. Thus, continuous measuring of 14CTOC ages of marine sediment might detect the turbidites which could not be observed in X-ray CT images. We will also present discrepancy between 14CTOC and 14Cforam ages corresponding to sediment source-to-sink.