Carbon, nitrogen, and oxygen isotopes of ostrich eggshells provide site-scale Pleistocene-Holocene paleoenvironmental records for eastern African archaeological sites
Carbon, nitrogen, and oxygen isotopes of ostrich eggshells provide site-scale Pleistocene-Holocene paleoenvironmental records for eastern African archaeological sites
复制标题
DOI：
10.1016/j.quascirev.2019.106142
复制
发表时间：
2020-02
影响因子：
4
通讯作者：
E. Niespolo;W. Sharp;C. Tryon;J. Faith;J. Lewis;Kathryn L. Ranhorn;S. Mambelli;Melanie J. Miller;T. Dawson
中科院分区：
文献类型：
--
作者：
E. Niespolo;W. Sharp;C. Tryon;J. Faith;J. Lewis;Kathryn L. Ranhorn;S. Mambelli;Melanie J. Miller;T. Dawson
定量的、日期明确的当地古环境记录对于以下方面是必要的：1）评估人类栖息地规模对区域到全球范围气候变化的反应；2）测试有关环境变化以及人类生物和文化进化影响的假设。鸵鸟蛋壳 (OES) 碎片在非洲考古序列中很常见，适合 14C 和 230Th/U 测年，其稳定碳（δ13C 值）和氮（δ15N 值）同位素组成分别跟踪当地植被和平均年降水量 (MAP)。我们回顾了之前对 OES 稳定同位素组成的解释，应用一种新颖的校准方法根据 δ15N 值估计古 MAP (PMAP)，并表明氧同位素（δ18O 值）记录蒸散量，如果水循环的其他组成部分受到限制，则蒸散量受温度、相对湿度和/或光合性能控制。 OES 有机部分的稳定同位素组成保持不变，至少~50 ka，表明有可能检查甚至更旧的 OES。我们提供了来自记录卢肯亚山（肯尼亚）和基塞塞 II（坦桑尼亚）中石器时代中晚期（MSA/LSA）过渡的考古遗址的~50-4 ka OES δ13C、δ15N 和 δ18O 值记录。稳定同位素代理表明两个地点的整个记录中当地古环境存在对比但微妙的变化，这可能是由当地生态和气候影响解释的，而区域规模的古气候记录无法解决这些影响。这些记录强调需要进行额外的当地研究来评估古环境和物质文化的协方差。此外，他们表明这两个地点的 MSA/LSA 转变并不是由古环境变化引起的。
Quantitative, well-dated, local paleoenvironmental records are necessary to 1) evaluate responses to regional to global-scale climate change at the scale of human habitats, and 2) test hypotheses regarding the effects of environmental change and human biological and cultural evolution. Ostrich eggshell (OES) fragments are common in African archaeological sequences, are amenable to14C and230Th/U dating, and their stable carbon (δ13C values) and nitrogen (δ15N values) isotopic compositions track local vegetation and mean annual precipitation (MAP), respectively. We review previous interpretations of the stable isotopic composition of OES, apply a novel calibration to estimate paleo-MAP (PMAP) from δ15N values, and show that oxygen isotopes (δ18O values) record evapotranspiration, which is controlled by temperature, relative humidity, and/or photosynthetic performance, if other components of the water cycle are constrained. The stable isotopic compositions of the organic fraction of OES remain unaltered to at least ∼50 ka, indicating potential to examine even older OES. We present a ∼50–4 ka record of OES δ13C, δ15N, and δ18O values from archaeological sites recording the Middle to Later Stone Age (MSA/LSA) transition at Lukenya Hill (Kenya) and Kisese II (Tanzania). Stable isotope proxies indicate contrasting but subtle changes in local paleoenvironment throughout the records at both sites, likely explained by local ecological and climatological effects that are not resolved by regional-scale paleoclimate records. These records highlight the need for additional local studies to assess the covariance of paleoenvironments and material culture. Furthermore, they indicate that the MSA/LSA transition at the two sites did not result from paleoenvironmental change.