NOAA/WDS Paleoclimatology - Santo Tomas Cave, Dos Anas Cave Geochemical Data from 12300 to 61 Cal Yr BP

We present a speleothem stable oxygen isotope record for the last 12.5 ka based on two stalagmites from western Cuba. The δ18O signal is interpreted to represent past precipitation variability. Both stalagmites show a pronounced transition from higher δ18O values (indicating drier conditions) to more negative δ18O values (suggesting wetter conditions) between 10 and 6 ka. This transition is also visible in a planktonic δ18O record off Haiti. On orbital timescales, the δ18O value of Caribbean precipitation, thus, strongly resembles the oxygen isotope composition of Caribbean surface water. On millenial timescales, the speleothem δ18O record shows a high correlation to a North Atlantic sea surface temperature (SST) record off West Africa as well as a similarity with the Bond events. Periods of lower North Atlantic SST correspond to less precipitation in the Caribbean and vice versa. The potential teleconnection to the Caribbean may reflect the position of the Intertropical Convergence Zone because a further southward position of the ITCZ leads to reduced precipitation in the northern Caribbean.

本研究基于古巴西部的两支石笋，构建了过去12.5千年的洞穴次生碳酸盐沉积（speleothem）稳定氧同位素记录。该δ¹⁸O信号被解释为指示了过去的降水变化。两支石笋均呈现出10至6千年期间，δ¹⁸O值从较高值（对应干旱环境）向更负值（对应湿润环境）的显著转变。该转变在海地周边海域的浮游δ¹⁸O记录中同样可见。在轨道尺度上，加勒比地区降水的δ¹⁸O值与加勒比地表水体的氧同位素组成高度相似。在千年尺度上，洞穴次生碳酸盐沉积的δ¹⁸O记录与西非近海的北大西洋海表温度（SST）记录呈高度相关，同时与邦德事件（Bond events）具有相似的变化特征。北大西洋海表温度偏低的时期对应加勒比地区降水减少，反之亦然。这种与加勒比地区的潜在遥相关可能反映了热带辐合带（ITCZ）的位置：当热带辐合带位置进一步南移时，加勒比北部的降水会相应减少。

搜集汇总

背景与挑战

背景概述

该数据集包含古巴西部Santo Tomas和Dos Anas洞穴的石笋地球化学数据，时间范围从12300到61 cal yr BP。数据以稳定氧同位素（δ18O）记录为主，用于重建过去降水变化，显示在10至6 ka期间从干燥向湿润条件的过渡。数据集揭示了加勒比地区降水与北大西洋海表温度之间的遥相关关系，并关联到热带辐合带的位置变化，为古气候研究提供重要参考。