NOAA/WDS Paleoclimatology - South China Sea ODP1148 Neogene Benthic Foraminiferal Isotope Data

General global cooling over the Neogene has been modulated by changes in Earth's orbital parameters. Investigations of deep-sea sediment sequences show that various orbital cycles can dominate climate records for different latitudes or for different time intervals. However, a comprehensive understanding of astronomical imprints over the entire Neogene has been elusive because of the general absence of long, continuous records extending beyond the Pliocene. We present benthic foraminiferal d18O and d13C records over the past 23 Ma at Ocean Drilling Program Site 1148 in the northern South China Sea and construct an astronomically tuned timescale (TJ08) for these records based on natural gamma radiation and color reflectance data at this site. Our results show that a 41 ka cycle has dominated sediment records at this location over the Neogene, displaying a linear response to orbital forcing. A 100 ka cycle has also been significant. However, it is correlated nonlinearly with Earth's orbital variations at the 100 ka band. The sediment records also display a prominent 405 ka cycle. Although this cycle was coherent with orbital forcing during the Oligocene and the early Miocene, it was not coherent with Earth's orbital variations at the 405 ka band over the whole Neogene. Amplification of Northern Hemisphere and Southern Hemisphere glaciation since the middle Miocene may be responsible for this change in sedimentary response. Our benthic foraminifera d18O and d13C records further exhibit amplitude variations with longer periods of 600, 1000, 1200, and 2400 ka. Apparently, these cycles are nonlinear responses to insolation forcing.

本存档古气候学（Paleoclimatology）研究数据集可通过美国国家海洋和大气管理局（NOAA）国家环境信息中心（NCEI）下属的古气候学世界数据服务中心（WDS）获取。该研究对应的NCEI研究分类为古海洋学（Paleoceanography）。数据集涵盖古海洋学相关参数，研究区域为西太平洋南海海域。时间覆盖区间为距今（BP）23103000至0个日历年。有关参数与研究区域的详细信息，请参阅元数据。使用本数据集时，请引用本研究。