P2C2: Testing Speleothem-Based Radiocarbon Calibrations Through A Process-Based Cave Study and a New 35 Kyr Calibration Curve

P2C2：通过基于过程的洞穴研究和新的 35 Kyr 校准曲线测试基于洞穴的放射性碳校准

• 批准号: 0903101
• 负责人: Kathleen Johnson
• 金额: $ 46.15万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0903101&HistoricalAwards=false
• 关键词: P2C2; Testing; Speleothem; Based; Radiocarbon

Funding is provided to improve the carbon-14 calibration curve that is used for dating paleoclimate samples. In general, geochemical modeling approaches will be used to study climatic controls on speleothem geochemistry while statistical analyses will be used to construct a new calibration curve. Specifically, the researcher will use speleothems from Heshang Cave, China to test the dead carbon fraction (DCF) effect on sample dating. The research goals include: (1) investigating the modern environmental controls on speleothem carbon-14 through expansion of the current environmental monitoring program to include carbon-14 and carbon-13 measurements of soil carbon, soil carbon dioxide, monthly modern calcite samples, monthly dripwater dissolved inorganic carbon samples, and cave air carbon dioxide for comparison with existing calibration data to constrain environmental controls on carbon cycling in the karst system and investigate links with other proxies; (2) investigating the location and structure of the radiocarbon bomb peak within the 2.5 meter annually-laminated HS4 stalagmite to determine soil-to-speleothem carbon transfer dynamics; (3) constructing a centennial-resolution Holocene carbon-14 record from HS4, tied to existing uranium-thorium (U-Th) dates, to investigate possible climatic controls on DCF over this time period; and (4) constructing a new, well-tested speleothem-based radiocarbon calibration curve from paired U-Th-carbon-14 dating of a 2.0 meter long stalagmite, HS7, which formed from 35,800 to 11,800 years ago. This research will support a new female investigator and students while strengthening international science collaborations.This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

为改进用于测定古气候样品年代的碳14校准曲线提供了资金。一般而言，将使用地球化学模拟方法来研究气候对洞穴地球化学的控制，同时将使用统计分析来构建新的校准曲线。具体地说，研究人员将使用中国和上洞的洞穴来测试死碳分数对样品测年的影响。研究目标包括：(1)通过扩展现有的环境监测计划，包括土壤碳、土壤二氧化碳、现代方解石样品、每月滴水溶解无机碳样品和洞穴空气二氧化碳的碳-14和碳-13的测量，以与现有的定标数据相比较，调查现代环境对洞穴碳14的控制；(2)调查放射性碳弹峰值的位置和结构，以确定土壤到洞穴的碳转移动力学；(3)根据HS4构造一个百年分辨率的全新世碳14记录，并与现有的铀-钍(U-Th)测年相联系，以研究这一时期可能对DCF的气候控制；以及(4)根据来自35,800-11,800年前的2.0米长的石笋HS7的成对U-Th-C-14测年，建立新的、经过充分测试的基于洞穴的放射性碳定标曲线。这项研究将支持一名新的女性研究人员和学生，同时加强国际科学合作。该奖项由2009年美国复苏和再投资法案(公法111-5)资助。