Revisiting the marine reservoir age in Baja California continental margin sediments using C-14 and 210Pb dating

Knowledge of the Marine Reservoir Effect (MRE) correction is fundamental in palaeoceanographic research to establish an accurate age-depth model for marine sedimentary records. However, during the last decades different MRE corrections have been applied in inconsistent ways for the same locality and same sediment cores, at Soledad Basin, Baja California, Mexico, creating confusion about the proper correction value of the marine reservoir effect (Delta R) to be applied. In contrast with the empirical approach previously used for assessing the Delta R value in Soledad Basin, in this study we applied an analytical approach based on the concurrent application of AMS-14C and 210Pbxs dating techniques made on sedimentary total organic carbon and foraminifera to determine new regional Delta R values from newly collected sediment cores from this site. Our results from Soledad Basin show a Delta R of 206 +/- 32 years for foraminifera and 706 +/- 42 years for organic carbon. Modeled ages using these results, and compared with those previously applied for the basin, highlight the relevance of the correct use of the local reservoir age as it can generate an offset of approximately 150 years if the other published Delta R were used. These differences can shift core chronologies by several decades and thus yield significant errors in palaeoceanographic reconstructions, which will be important to remedy in future work.

Automated summary

Knowledge of the Marine Reservoir Effect (MRE) correction is crucial in establishing accurate age-depth models for marine sediment records. Inconsistent application of MRE corrections at Soledad Basin, Baja California, Mexico has led to confusion about the proper correction value of Delta R. This study used an analytical approach to determine new regional Delta R values, highlighting the importance of correct local reservoir age usage to avoid significant errors in palaeoceanographic reconstructions.