Collaborative Research: Testing the Reliability of Paleo Ventilation Estimates

来自赤道太平洋深层沉积物岩心的PIS初步数据显示，有证据表明存在古老的放射性碳年龄，因此存在随着最后一次冰川末期开始消融而带到地表的古老、通风不良的底层水，从而可能解释放射性碳含量长期下降和大气中二氧化碳水平同时上升的原因。PIS建议进一步评估这一通风信号，并通过对选定的额外岩心进行14C和230次测量来测试其重要性，以便更好地了解海底过程的影响。此外，钍剖面将用于测试14-C测年的有孔虫丰度中最大值的重要性。这种方法将被用来评估底栖有孔虫的累积速率，以及风选和沉积物聚焦在创造海底丰度峰值方面的可能作用。钍数据还将有助于完善赤道东太平洋过去25年来千年尺度事件的年代学。广泛的影响：这些发现的科学影响可能对其他古气候研究具有很大的影响。外展和教育工作包括培训教师、学生和一名博士后研究员。

The PIs' preliminary data from sediment cores from deep equatorial Pacific show evidence of old radiocarbon ages and thus the presence of old, poorly ventilated bottom water brought to the surface as deglaciation began at the end of the last glacial, thereby potentially explaining the prolonged decrease in radiocarbon content and a concurrent increase pCO2 levels of the atmosphere. The PIs propose to evaluate this ventilation signal further and test its significance through a combination of 14C and 230Th measurements on selected additional cores in order to better understand the effects of benthic processes. In addition, Thorium profiling will be used to test the significance of maxima in foraminiferal abundance that are dated with 14-C. This method will be used to evaluate the accumulation rates of benthic foraminifera and the possible role of winnowing and sediment focusing in creating benthic abundance peaks. Thorium data will also help refine chronology of millennial-scale events in the eastern Equatorial Pacific over the last 25 K.Y.Broader Impacts: The scientific impact of the findings could be strong for other paleoclimate research. Outreach and educational efforts include training of teachers, students and a post-doctoral researcher.