Collaborative Research: The Ocean-Atmosphere Carbon Cycle and Climate Change: Constraints from Radiocarbon and Climate History

合作研究：海洋-大气碳循环和气候变化：放射性碳和气候历史的限制

• 批准号: 0405109
• 负责人: Jeffrey Dorale
• 金额: $ 13.74万
• 依托单位: University of Iowa
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-10-13 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0405109&HistoricalAwards=false
• 关键词: Collaborative; Research; Ocean; Atmosphere; Carbon

The PIs will obtain and interpret cave speleothem 14C/12C records and high-resolution climate records from the same samples from Crevice Cave, Missouri and Hulu Cave, Nanjing, China. The records will be dated independently and precisely with high precision 230Th and 231Pa techniques enabling determination of initial 14C/12C values and establishment of an absolute chronology. The PIs will use the records to (1) reconstruct atmospheric 14C/12C for the whole radiocarbon timescale (the last 45 ky) and (2) compare those records directly to the climate records from the same samples. The former will place constraints on the operation of the ocean-atmosphere carbon cycle since glacial times. The latter will characterize the interplay between changes in the carbon cycle and climate change. Both have implications for the understanding of the current and future carbon cycle. Recent work indicates extremely high and variable atmospheric 14C/12C for much of the interval between 44 and 34 Ka. The radiocarbon values are generally well above values that can be achieved with the modern carbon cycle, even if terrestrial and solar magnetic fields were negligible. These data therefore require significant differences between the modern and glacial carbon cycles, as well as large temporal changes in the glacial carbon cycle. The far-reaching implications of this work require replication, ideally at sites other than the Bahamas, the site where this evidence was collected.

PI将从密苏里州裂缝洞和中国南京葫芦洞的相同样品中获得并解释洞穴洞穴沉积物14 C/12 C记录和高分辨率气候记录。将使用高精度的230 Th和231 Pa技术对这些记录进行独立和精确的定年，从而确定初始14 C/12 C值并建立绝对年表。PI将使用这些记录来（1）重建整个放射性碳时间尺度（最后45 ky）的大气14 C/12 C，（2）将这些记录直接与来自相同样本的气候记录进行比较。前者将限制自冰川时代以来海洋-大气碳循环的运作。后者将描述碳循环变化与气候变化之间的相互作用。两者都对理解当前和未来的碳循环有影响。最近的研究表明，在44和34 Ka之间的大部分时间里，大气14 C/12 C极高且可变。放射性碳值通常远高于现代碳循环所能达到的值，即使地球和太阳磁场可以忽略不计。因此，这些数据需要现代和冰川碳循环之间的显着差异，以及冰川碳循环的大的时间变化。这项工作的深远影响需要复制，最好是在巴哈马以外的其他地点复制，巴哈马是收集这一证据的地点。