Evidence for long-term averaging of strontium in bovine enamel using TIMS and LA-MC-ICP-MS strontium isotope intra-molar profiles
Evidence for long-term averaging of strontium in bovine enamel using TIMS and LA-MC-ICP-MS strontium isotope intra-molar profiles
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DOI：
10.1179/146141010x12640787648694
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发表时间：
2010-04-01
影响因子：
1.5
通讯作者：
Horstwood, Matthew S. A.
中科院分区：
文献类型：
--
作者：
Montgomery, Janet;Evans, Jane A.;Horstwood, Matthew S. A.
牙釉质的高空间分辨率微量采样为重建气候、环境、饮食和流动性提供了高时间分辨率同位素数据的可能性。关于牙釉质成熟期的持续时间和模式，以及时间线的存在和方向，仍然存在疑问。用La-MC-ICPMS测量了约400亩m的陨石坑，并对考古牛第三磨牙的釉质横切面进行了TIMS分析，以研究掺入锶的长期平均值。两种方法都得到了相同的逐渐增加的同位素分布，表明空间分辨率的大幅提高并没有改变所获得的响应分布。结果表明，即使在微观尺度上，锶的掺入时间也超过12个月。输入信号的平均化可能是由于锶在骨骼中的长期滞留和在体池中的再循环，或者是在微观尺度上牙釉质的长期成熟所致。无论是哪种机制，除非不同来源的锶供应存在很大的不平衡，否则可能无法从牛的磨牙釉质中恢复高时间分辨率的锶同位素比值。因此，锶同位素剖面可能与较轻的同位素系统的剖面不同步。
High spatial resolution micro-sampling of tooth enamel offers the possibility of high temporal resolution isotope data to reconstruct climate, environment, diet and mobility. Questions remain about the duration and pattern of the maturation phase of enamel and the existence and direction of chronological 'time-lines'. LA-MC-ICP-MS measurements of c. 400 mu m craters and TIMS analyses of transverse enamel sections of an archaeological bovine third molar were undertaken to investigate the long-term averaging of incorporated strontium. The same gradually increasing isotope profile was obtained from both approaches, indicating that the large increase in spatial resolution did not change the response profile obtained. The results suggest that even at the microscopic scale, strontium is incorporated over a period in excess of 12 months. Averaging of the input signal may result from both long-term retention of strontium in the skeleton and recirculation in the body pool, or long-term maturation of enamel on a microscopic scale. Whichever mechanism is responsible, it may not be possible to recover strontium isotope ratios with a high time resolution from cattle molar enamel unless there is a large imbalance in the amount of strontium supplied by different sources. Consequently, strontium isotope profiles may not be synchronous with those of lighter isotope systems.