Collaborative Research: Calibrating the Isotopologue-47 Geothermometer in Soils

合作研究：校准土壤中的 Isotopologue-47 地温计

• 批准号: 0843294
• 负责人: John Eiler
• 金额: $ 9.51万
• 依托单位: California Institute of Technology
• 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: 2009-03-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0843294&HistoricalAwards=false
• 关键词: Collaborative; Research; Calibrating; Isotopologue; 47

Use of isotopologue-47 paleothermometer over the past several years is an exciting new development that holds enormous potential for reconstruction of paleotemperatures in the deeper geologic record. Paleosol carbonates are a particularly attractive target for such analysis because they are so abundant in the geologic record, and because temperature in soils displays a highly predictable relationship to air temperature (unlike in many other systems). Before this potential can be realized, the relationship between temperatures estimated from isotopologue-47 analysis (expressed as Ä47) of modern soil carbonate, and that of local air and soil temperature must be rigorously established. We present unpublished results from a number of modern soils that show that temperature estimates from Ä47 values systematically exceed those of modeled summer maximum temperatures by 6±2°C. Part of the excess?up to 2-4°C?may be explained asymmetric summer heating of soil. The remaining excess may be the result of contamination, the wrong assumed soil temperatures, or perhaps non-equilibrium kinetic effects. Whatever the cause, the more key question is whether the offset between actual and estimated values is systematic. This must be tested with a much larger sample set and with direct measurements of soil temperature. Here we propose to monitor temperature and other parameters in modern soils from a range of settings for comparison to Ä47 estimates of temperatures. Our study sites include Arizona, Nevada, Hawaii, and NW Argentina, taking in most of the natural temperature range for soil carbonate formation. Broader impacts of this on the larger scientific community will be substantial, given the intense interest in using this new geothermometer on a variety of research questions. Exciting potential applications of the new paleothermometer include reconstruction of paleotemperature (±2°C) using such long paleosol time series (17 Myr) as the Siwaliks in Pakistan, and of paleoelevation, through the strong sensitivity of the temperature to elevation in the world?s major orogens. Field and laboratory measurements and data analysis are ideal training opportunities for undergraduates in the sciences, who will be recruited from several institutions to participate in field and labwork.

过去几年，isotopologue-47 古温度计的使用是一个令人兴奋的新发展，它在重建更深的地质记录中的古温度方面具有巨大的潜力，古土壤碳酸盐是此类分析特别有吸引力的目标，因为它们在地质记录中非常丰富。并且由于土壤温度与气温之间存在高度可预测的关系（与许多其他系统不同），在实现这种潜力之前，通过 isotopologue-47 分析估算出的温度之间的关系（表示为）。必须严格建立现代土壤碳酸盐的温度估计值以及当地空气和土壤温度的温度值，我们提供了许多现代土壤的未发表结果，这些结果表明，根据 47 值估计的温度系统地比模拟的夏季最高温度高出 6 倍。 ±2°C。部分超出范围（高达 2-4°C）可能是由于夏季土壤加热不对称造成的，其余的超出范围可能是污染、错误假设的土壤温度或可能不平衡的结果。无论原因是什么，更关键的问题是实际值和估计值之间的偏差是否是系统性的，这必须通过更大的样本集和直接测量土壤温度来进行测试。我们的研究地点包括亚利桑那州、内华达州、夏威夷州和阿根廷西北部，考虑了大部分自然温度范围对土壤碳酸盐形成的更广泛影响。鉴于激烈的竞争，更大的科学界将是巨大的对使用这种新的地温计解决各种研究问题的兴趣 新古温度计的令人兴奋的潜在应用包括使用巴基斯坦的 Siwaliks 等长古土壤时间序列 (17 Myr) 重建古温度 (±2°C)，以及古海拔，由于世界主要造山带的温度对海拔高度敏感，现场和实验室测量和数据分析是科学本科生的理想培训机会，他们将从多个机构招募。参与现场和实验室工作。