Collaborative Research: Testing the Reliability of Paleo Ventilation Estimates

合作研究：测试古通风估计的可靠性

• 批准号: 1029936
• 负责人: Jerry McManus
• 金额: $ 22.7万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-10-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1029936&HistoricalAwards=false
• 关键词: Collaborative; Research; Testing; Reliability; Paleo

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.

研究所从赤道太平洋深处的沉积物岩心获得的初步数据显示，存在古老的放射性碳年龄，因此，在末次冰期结束时开始的冰消作用中，存在古老的、通风不良的底层水被带到地表，从而可能解释了放射性碳含量长期下降和大气中pCO 2水平同时增加的原因。PI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14 C和230 Th测量来测试其意义，以便更好地了解底栖过程的影响。 此外，钍剖面将用于检验用14-C测年的有孔虫丰度最大值的意义。这一方法将用于评价底栖有孔虫的积累率以及扬沙和沉积物集中在形成底栖丰度峰值方面可能发挥的作用。钍数据还将有助于完善赤道太平洋东部在过去25 K.Y.更广泛的影响千年尺度事件的年表：这些发现的科学影响可能对其他古气候研究很强。外联和教育工作包括培训教师、学生和一名博士后研究员。