Improving the Precision and Extending the Age Range of Luminescence Dating of Pleistocene Sediment

提高更新世沉积物发光测年精度并扩大年龄范围

• 批准号: 9809354
• 负责人: Glenn Berger
• 金额: $ 15.17万
• 依托单位: Nevada System of Higher Education, Desert Research Institute
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-15 至 2007-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9809354&HistoricalAwards=false
• 关键词: Improving; Precision; Extending; Age; Range

9809354 Berger There is a dearth of accurate and precise numeric dating techniques for Pleistocene terrestrial sediment older than 40-50 ka, the usual limit of radiocarbon dating. Luminescence dating methods for unheated sediment have the potential (based on kinetics studies) to directly date detrital- feldspar burial time to well beyond 1 ma, a time period embracing at least half the Pleistocene and therefore many glacial-interglacial cycles. This award supports high- precision measurements on loess samples using the new, more precise, infra-red- stimulated-luminescence (IRSL) dating procedure. Use of this method is expected to improve luminescence- dating precision for loess by more than a factor of two, in the established time range for IRSL dating (400Ka). Companion termoluminescence (TL) measurements will be made on several samples to validate previous TL results and to improve their precision using more recent TL experimental protocols. Furthermore, both TL and IRSL measurements will be made on new loess samples to be collected from sites in Alaska and the Yukon Territory (Canada). These sites have newly documented independent numerical ages up to 2 Ma, based on paleomagnetic polarity-reversal boundaries and fission track ages of volcanic ash beds. Improved luminescence dating of Pleistocene terrestrial feldspars should benefit global efforts to extract time-series data from much of the Pleistocene land record.

9809354 Berger 对于年龄超过 40-50 ka（放射性碳测年的通常限制）的更新世陆地沉积物，缺乏准确和精确的数字测年技术。 未加热沉积物的发光测年方法有潜力（基于动力学研究）直接确定远超过 1 Ma 的碎屑长石埋藏时间，该时间段至少涵盖更新世的一半，因此包含许多冰期-间冰期旋回。 该奖项支持使用新的、更精确的红外刺激发光（IRSL）测年程序对黄土样本进行高精度测量。 在IRSL测年的既定时间范围（400Ka）内，使用该方法预计可以将黄土的发光测年精度提高两倍以上。 将对多个样品进行伴随热发光 (TL) 测量，以验证之前的 TL 结果并使用最新的 TL 实验方案提高其精度。 此外，还将对从阿拉斯加和育空地区（加拿大）采集的新黄土样本进行 TL 和 IRSL 测量。 这些地点根据古地磁极性反转边界和火山灰层的裂变径迹年龄，新记录了高达 2 Ma 的独立数值年龄。 更新世陆地长石的发光测年技术的改进应该有利于全球从大部分更新世陆地记录中提取时间序列数据的努力。