Intra-Annual Radiocarbon (14C) Offsets, Chronology and Paleoclimate

年内放射性碳 (14C) 偏移、年代学和古气候

• 批准号: 2303502
• 负责人: Sturt Manning
• 金额: $ 50万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2303502&HistoricalAwards=false
• 关键词: Intra; Annual; Radiocarbon; 14C; Offsets

This project specifically aims to test whether small growing-season-related Carbon-14 offsets exist for two Mediterranean-type areas comprised of the East Mediterranean-Middle East (EMME) and the Southwest United States (SW USA), as well as one humid sub-tropical area Southeast United States (SE USA), and, if identified, quantify their scale and paleoclimate relevance.Carbon-14 is relevant to many temporally-dependent investigations in paleoclimate and related fields, as well as a key tracer for a number of carbon-cycle models central to paleoclimate research. Recent studies have revealed a distinct seasonal cycle in atmospheric Carbon-14. With high-precision measurement it seems plausible that plants growing at substantially different times of the year may reflect different portions of this seasonal Carbon-14 cycle. This research has the potential to advance knowledge in the fields of paleoclimate, paleoecology, and archaeology. Precise age-depth modelling is critical to establishing the timing of past events, and the research will attempt to improve radiocarbon age calibration by investigating the potential impacts of seasonal phenological differences in annual radiocarbon uptake by plants and how those biases may impact calibration based on widely used but spatially-biased northern hemisphere calibration curve.Until recently, analytical precision precluded exploring such differences since they were below measurement detection but advances in analytical measurements now make this inquiry possible. Although small, these analytical differences could have significant effects on carbon-related dating, especially at times of reversals and plateaus in the Carbon-14 calibration curve. The potential Broader Impacts include involving undergraduates in dendrochronology research at both Cornell University and the University of Georgia while also supporting an early career scientist at Georgia. The project would also support a PhD student who will develop outreach materials for the public. Research results will be distributed during International Archaeology Day and outreach to middle school students through the Expanding Your Horizons (EYH) program in Ithaca, New York.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目的具体目的是测试东地中海-中东(EMME)和美国西南部(西南)组成的两个地中海类型地区以及美国东南部(美国东南部)一个潮湿的亚热带地区是否存在与生长季相关的小的碳-14偏移量，如果确定，则量化其规模和古气候相关性。碳-14与古气候和相关领域的许多时间相关调查相关，并是一些对古气候研究至关重要的碳循环模型的关键示踪剂。最近的研究表明，大气中的碳-14存在明显的季节性循环。有了高精度的测量，一年中生长在不同时间的植物可能反映了季节性碳14循环的不同部分，这似乎是有道理的。这项研究有可能促进古气候、古生态和考古学领域的知识进步。精确的年龄深度模型是确定过去事件时间的关键，这项研究将试图通过调查植物年放射性碳吸收中季节物候差异的潜在影响，以及这些偏差如何影响基于广泛使用但空间上有偏差的北半球校准曲线的校准，来改进放射性碳年龄校准。直到最近，分析精度还无法探索这种差异，因为它们低于测量检测，但现在分析测量的进步使这一研究成为可能。这些分析差异虽然很小，但可能会对碳相关的测年产生重大影响，特别是在碳14校准曲线出现反转和停滞的时候。潜在的更广泛的影响包括让康奈尔大学和佐治亚大学的本科生参与树状年代学研究，同时还支持佐治亚州的一名早期职业科学家。该项目还将支持一名博士生，他将为公众编写宣传材料。研究成果将在国际考古日期间通过纽约伊萨卡的扩展你的视野(EYH)计划向中学生分发。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。