Amino Acid Racemization Dating of the Middle Stone Age of Africa: Improvement of Precision with Ostrich Eggshell

非洲中石器时代的氨基酸外消旋定年：利用鸵鸟蛋壳提高精确度

• 批准号: 0002224
• 负责人: Alison Brooks
• 金额: --
• 依托单位: George Washington University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-15 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0002224&HistoricalAwards=false
• 关键词: Amino; Acid; Racemization; Dating; Middle

This research is aimed at developing dating techniques for African archaeological sites that are too old to be dated by radiocarbon (45,000 years before present) and which lack appropriate volcanic materials for high-precision argon-argon dating. The methods may also help to resolve problems of chronology and disturbance in archaeological sites. Such chronological resolution is essential if we are to understand such issues as the African origins of modern humans and the origins of modern behavior, both of which may relate back to the time period of the late Middle and upper Pleistocene (40,000-200,000 years before present) and the associated Middle Stone Age culture. The proposed research would improve the precision of amino acid racemization dating of ostrich eggshell (one of the more common materials in archaeological sites), through analysis of patterns of spatial and temporal variation in temperature at six African sites in Tanzania, Botswana, Namibia and South Africa. Knowledge of the Pleistocene temperature histories of these sites will also indicate how each region (tropical vs. temperate zones) reflected global cooling and warming patterns during the late Pleistocene and allow evaluation of human response to these climatic variations.

这项研究的目的是为非洲考古遗址开发测年技术，这些遗址太古老了，无法用放射性碳测年（距今45000年），而且缺乏适当的火山物质来进行高精度的氩-氩测年。这些方法还有助于解决考古遗址的年代学和干扰问题。如果我们要理解现代人类的非洲起源和现代行为的起源等问题，这种时间顺序的解决是必不可少的，这两个问题都可以追溯到中新世晚期和上新世时期（距今4万至20万年）以及相关的中石器时代文化。本研究通过对坦桑尼亚、博茨瓦纳、纳米比亚和南非6个非洲遗址温度时空变化规律的分析，提高了鸵鸟蛋壳（考古遗址中较常见的材料之一）氨基酸消旋化定年的精度。了解这些地点的更新世温度历史也将表明每个地区（热带与温带）在更新世晚期如何反映全球变冷和变暖模式，并允许评估人类对这些气候变化的反应。