Glacial South Atlantic Mid Ocean Circulation and ventilation ages changes derived from cold water corals from off Brazil

巴西近海沉积物岩心中深海珊瑚的Th/U和14C联合测年确定了珊瑚的生长期和深水沐浴珊瑚的年龄。在对两个沉积物岩心样品的初步研究中，我们发现珊瑚只在海因里希事件3(H3)、HI和年轻仙女木之后的特定时间段生长。在这个项目中，我们希望首先增加珊瑚样本的数量，以更高的分辨率证实我们之前的观察结果，其次我们还将研究埋藏珊瑚的沉积物的地球化学。沉积物的231Pa230th比值应提供有关水的通风程度的更多信息，并可能解释珊瑚生长加速的原因。

The combined Th/U and 14C dating of deep sea corals in sediment cores from off Brazil determines the period of growth of the corals and the age of the deep water bathing the corals. During a preliminary study on samples from two sediment cores we have found that corals grew only during specific periods of time foiiowing the Heinrich event 3 (H3), HI and the Younger Dryas. In this project we want first to increase the number of coral samples, to confirm our previous observations at a higher resolution, and second we will study also geochemistry ofthe sediments embedding the corals. The 231Pa/230Th ratios ofthe sediments should deliver additional information about the degree of ventilation of the water and possibly explain the reasons for the enhanced coral growth.