Comparison of bulk organic carbon and radiocarbon ages in coastal sediments: implications for age model reconstruction and application

Abstract

Bulk organic carbon and radiocarbon ages from marine shell fragments in coastal marine sediments were compared for the late Holocene core sediments collected from the southern continental shelf area of the Korean peninsula. Our results indicated that the radiocarbon ages of organic carbon were older than those of shell fragments. The age differences are around 1,150-1,860 years in conventional radiocarbon age at the same depth. There could be distinctive contamination of the old terrigenous carbon in sediments, even though the C/N ratio and d 13C ratios of organic carbon indicate that most of the organic materials in studied core sediment are in situ marine origin. This study suggests that the radiocarbon organic carbon ages in marine sediment are generally older than inorganic carbon ages determined by shell fragments and foraminiferal tests, therefore, it should be careful to use age data by bulk organic carbon and age model reconstruction.