Collaborative Research: Testing the Reliability of Paleo Ventilation Estimates

PIs从赤道太平洋深处的沉积物岩心中获得的初步数据显示了古老的放射性碳年代的证据，因此，随着末次冰期结束时冰川消退开始，存在着古老的、通风不良的底部水，这些水被带到地表，从而可能解释了放射性碳含量的长期下降和同时大气中二氧化碳分压水平的增加。pi建议进一步评估该通风信号，并通过在选定的其他岩心上结合14C和230测量来测试其重要性，以便更好地了解底栖生物过程的影响。此外，钍谱分析将用于测试有孔虫丰度最大值的意义，这些丰度的年代为14-C。该方法将用于评估底栖有孔虫的积累速率，以及筛选和沉积物聚焦在形成底栖生物丰度峰值中的可能作用。钍数据还将有助于完善过去25千年来东赤道太平洋千年尺度事件的年表。更广泛的影响：这些发现的科学影响可能对其他古气候研究有很强的影响。外联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.