Holocene Marine Radiocarbon Reservoir Age Variations in the Taiwan Strait
Abstract
Marine reservoir age is necessary for calibrating the radiocarbon dates of aquatic carbonate samples, such as corals, mollusks, or planktonic foraminifera, due to the long residence time of carbon in the ocean. Marine radiocarbon reservoir age (R) not only varies temporally with changes in water mass mixing and air-sea CO2 exchange rates, but also varies spatially with local oceanographic and climatic conditions, which makes the regional/local marine reservoir age correction (ΔR) equally important. Although many marine reservoir age records have been reported in the western Pacific, information from the Taiwan Strait is scarce, despite being an important water mass that connects the South China Sea (SCS) in the south and the East China Sea in the north. In this study, we analyzed fossil surface coral samples collected from the Penghu Archipelago in the middle of the Taiwan Strait to reconstruct the Holocene R record of the area.
The R and ΔR values for the Taiwan Strait during the past 7000 Cal BP were calculated using results from 14C analyses on 234U-230Th dated surface corals. Our preliminary results show R values of up to 550 years in the Taiwan Strait around 6000 Cal BP, similar to records in the SCS. However, our record exhibited slightly lower values than the SCS between 3500-4000 and between 1500-2000 Cal BP. This observation implies that R in the Taiwan Strait was affected by different factors from those in the SCS during the mid- to late Holocene. ΔR values in our study calculated by the MARINE 20 database and recalculated previous published data produce negative values, distinctive from previous ΔR results. This reflects that the MARINE 20 is substantially different from previous calibration curves, and emphasizes that published ΔR data need to be recalculated for more accurate comparison between radiocarbon results corrected using different calibration curves.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFMPP15D0688L