Variability in the marine radiocarbon reservoir effect in Muscat (Sultanate of Oman) during the 4th millennium BC: reflection of taphonomy or environment?
Variability in the marine radiocarbon reservoir effect in Muscat (Sultanate of Oman) during the 4th millennium BC: reflection of taphonomy or environment?
复制标题
公元前四千年马斯喀特（阿曼苏丹国）海洋放射性碳库效应的变化：埋藏学或环境的反映？
DOI：
10.1016/j.jas.2012.01.043
复制
发表时间：
2012
影响因子：
2.8
通讯作者：
C. Moreau
中科院分区：
文献类型：
--
作者：
A. Zazzo;O. Munoz;J. Saliège;C. Moreau
由于可确定年代的陆地人工制品相对稀少，对干旱地区的考古沿海遗址进行放射性碳（14 C）测年具有挑战性。海洋人工制品提供了丰富的碳源，这在技术上很容易确定年代，但放射性碳年代测定需要根据全球平均海洋14 C储层年龄（ΔR）的局部变化进行校正。在考古遗址中，这通常是通过比较同时代的陆地和海洋样品之间的14 C年龄来完成的，这些样品没有内置的年龄。在这里，我们提出了一项研究的结果，旨在确定本地14 C海洋水库效应（MRE）沿着东海岸的阿拉伯半岛在公元前4千年，一个时期的重要文化，人口和社会的变化，在这一地区。以前根据相关的贝壳和木炭对MRE的估计相差约40014 C年，这严重限制了根据海洋材料在该地区建立精确的年表。为了尽可能多地获得同时期的陆地-海洋生物对，以便对该地区的地雷风险教育进行新的评估，我们对最近在Ra's al-Hamra RH 5仔细挖掘的三个坟墓中发现的木炭、贝壳、鱼和龟骨以及人骨进行了年代测定。一个很大的变化之间的木炭（高达24014 C年）和海洋标本（高达78514 C年）存在于同一个坟墓。这种变化归因于内置的年龄，成岩作用和可能的环境因素，但不能排除埋藏过程。我们丢弃了最古老的木炭，并使用在人类磷灰石上获得的14 C年龄作为截止值，以去除海洋异常值。三个坟墓中有两个提供了陆地和海洋生物组合，在统计上没有差异，用于计算平均MRE为645 ± 4014 C年（ΔR = 255 ± 5514 C年）。这一数值与先前基于巴基斯坦海域海洋沉积物14 C测年的估计值一致，表明阿拉伯海自公元前4千纪以来MRE的稳定性。
Radiocarbon (14C) dating of archaeological coastal sites in arid areas is challenging because of the relative rarity of datable terrestrial artefacts. Marine artefacts provide an abundant source of carbon, which is technically easy to date but radiocarbon dates need to be corrected for local variations from the global average marine14C reservoir age (ΔR). In archaeological sites, this is usually done by the comparison of the14C age measured between coeval pairs of terrestrial and marine samples that have no inbuilt age. Here, we present the results of a study that aims to determine the local14C marine reservoir effect (MRE) along the Eastern coast of the Arabic Peninsula during the 4th millennium BC, a period of important cultural, demographic and social changes in this region. Previous estimates of the MRE based on associated shells and charcoal vary by about 40014C yr and this is a serious limitation to the establishment of a precise chronology in the area based on marine material. In order to maximize the chances to obtain contemporaneous terrestrial–marine pairs for a new assessment of the MRE in this region we dated charcoal, shells, fish and turtle bones as well as human bones found in three recently and carefully excavated graves from Ra’s al-Hamra RH5. A large variability was found between charcoals (up to 24014C yr) and marine specimens (up to 78514C yr) present in the same grave. This variability was attributed to inbuilt ages, diagenesis and possibly environmental factors although taphonomic processes cannot be excluded. We discarded the oldest charcoals and used the14C ages obtained on human apatite as a cut-off value to remove the marine outliers. Two out of the three graves provided terrestrial and marine assemblages which did not differ statistically and were used to calculate an average MRE of 645 ± 4014C yr (ΔR = 255 ± 5514C yr). This value is consistent with previous estimates based on the14C dating of marine sediments off Pakistan and suggests stability of the MRE in the Arabian Sea since the 4thmillennium BC.