Sea surface temperature and terrestrial biomarker records of the last 260 ka of core MD05-2904 from the northern South China Sea

This paper reports high-resolution biomarker records of the last 260 ka for core MD05-2904 from the northern South China Sea (SCS). The sea surface temperature (SST) record using the U ₃₇^k′ index reveals a minimum of 21.5°C (MIS 2) and a maximum of 28.3°C (MIS 5.5), for a temperature difference of almost 7°C, and provides the longest high-resolution U ₃₇^k′ SST record in northern SCS. The content of odd-number long chain n-alkanes and several n-alkanes indexes such as the CPI, ACL and the C₃₁/C₂₇ ratio, all reveal generally higher values during the glacials and lower values during the interglacials. Terrestrial input as indicated by n-alkane content was mostly controlled by sea-level changes: During the glacials, lower sea-level exposed the continental shelf to enable rivers to transport more terrestrial materials to the slope; and the situation reverses during the interglacials. The n-alkane indexes changes reveal more n-alkanes from contemporary vegetation during glacials as a result of the proximity of the core site to the source region, while the increases in ACL and C₃₁/C₂₇ ratio during glacials indicate a change to more grassy vegetation. However, the highest values for CPI, ACL and the C₃₁/C₂₇ ratio all occurred during late MIS 3, and it was suggested that this period was characterized by a strong summer monsoon-dominated humid climate which resulted in a denser vegetation for the exposed continental shelf region. Supported by the National Natural Science Foundation of China (Grant Nos. 40676032, 40776029 and 40403012) and the Innovation Research Group of the National Natural Science Foundation of China (Grant No. 40621063)