Carbon, hydrocarbon and alkenone composition and indices of ODP Hole 167-1016C sediments

Total organic carbon (TOC) and calcium carbonate (CaCO3) concentrations were determined for 304 samples, and biomarkers were analyzed for 101 samples from Core 167-1016C-1H. TOC varies between 1% and 2%, and CaCO3 is typically 1%-4%, with peaks reaching 14%. Paleotemperature estimated from Uk'37 varies from 8.5° to 17.5°C. The Uk'37 variation implies that Core 167-1016C-1H covers oxygen isotope Stages 1-6. Peaks of diatom-derived C25:1 HBI alkene concentrations occur during warming intervals, suggesting intensified upwelling during deglaciation. The concentrations of haptophyte-derived alkenones and diatom-derived C25:1 HBI alkene vary out of phase, which presumably resulted from the changes in the mode of nutrient supply to surface mixed layer. Maximal CaCO3 contents (>10%) were observed in both warming and cooling intervals. The peak in cooling interval relates to an alkenone maximum, whereas the peaks in warming intervals do not. This implies that carbonate production is not the only factor controlling carbonate compensation depth at this site, and it suggests considering the changes in North Pacific deep-water chemistry. Petroleum-type compounds are present in Site 1016 sediments. Their concentrations are maximized in the warming intervals that correspond to the timing of destruction of a huge tar mound off Point Conception. The tarry material was presumably transported by the Arguello Fan system to Site 1016.

本研究对167-1016C-1H岩心（Core 167-1016C-1H）的304个样品开展了总有机碳（Total organic carbon, TOC）与碳酸钙（calcium carbonate, CaCO3）浓度测定，并对其中101个样品进行了生物标志物（biomarkers）分析。其中，TOC含量介于1%~2%之间，CaCO3含量通常为1%~4%，峰值最高可达14%。基于Uk'37指标估算的古温度范围为8.5℃~17.5℃。Uk'37的变化特征表明，该岩心覆盖了氧同位素阶段（oxygen isotope Stages）1至6。
硅藻源C25:1 HBI烯烃（diatom-derived C25:1 HBI alkene）的浓度峰值出现在升温期，指示冰消期上升流作用增强。定鞭金藻源烯酮（haptophyte-derived alkenones）与硅藻源C25:1 HBI烯烃的浓度呈反相变化，推测该现象源于表层混合层营养供给模式的改变。
高CaCO3含量（>10%）同时出现于升温期与降温期。其中，降温期的CaCO3峰值对应烯酮含量最大值，而升温期的CaCO3峰值则无此对应关系，这意味着该站位的碳酸盐补偿深度（carbonate compensation depth）并非仅受碳酸盐产率控制，同时提示需关注北太平洋深层水化学（North Pacific deep-water chemistry）的变化。
1016站位沉积物中检出石油类化合物（Petroleum-type compounds），其浓度在升温期达到峰值，该时段与康塞普西翁角（Point Conception）外巨型沥青丘的破坏时间相吻合。推测这些沥青质物质通过阿圭略扇体系统（Arguello Fan system）被搬运至1016站位。