Geochronological Potential of Isoleucine Epimerization in Calcite Speleothems
Geochronological Potential of Isoleucine Epimerization in Calcite Speleothems
复制标题
方解石洞穴中异亮氨酸差向异构化的年代学潜力
DOI：
10.1006/qres.1994.1006
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发表时间：
1994
影响因子：
2.3
通讯作者：
Helge Gilje
中科院分区：
文献类型：
--
作者：
S. Lauritzen;John Erik Haugen;R. Løvlie;Helge Gilje
摘要 测定方解石洞穴中异亮氨酸差向异构化的程度，以评价非生物方解石中的氨基酸外消旋方法。通过序列分析来自挪威北部 Hamarnesgrotta 的 5.5 厘米厚的流石板的氨基酸浓度、组成和 26 个水平的异亮氨酸差向异构化。 U 系列日期提供独立的时间顺序控制。差向异构化随地层深度单调增加，并随 U 系列年龄线性增加，与氨基酸浓度无关。差向异构化速率根据 U 系列日期进行校准，并且外推到超出 U 系列限制的较低地层，得出的绝对年龄估计值与来自同一洞穴的古地磁数据一致。结果表明，如果经过充分校准，氨基酸测年法适用于洞穴材料，其到达时间跨度超出了传统测年方法的范围。洞穴中的氨基酸可能来自表层土壤，并与方解石中的棕色腐殖质相关。
Abstract The extent of isoleucine epimerization in a calcite speleothem was determined to evaluate the amino acid racemization method in abiotic calcite. A 5.5-cm-thick flowstone slab from Hamarnesgrotta, northern Norway, was analyzed for amino acid concentration, composition, and isoleucine epimerization at 26 levels through the sequence. U-series dates provide an independent chronologic control. Epimerization increases monotonically with stratigraphic depth and linearily with U-series age, independent of amino acid concentrations. The rate of epimerization is calibrated against the U-series dates, and extrapolation into lower strata beyond the U-series limit yields absolute age estimates that are consistent with paleomagnetic data from the same speleothem. The results suggest that, if adequately calibrated, amino acid dating is applicable to speleothem material reaching time spans beyond the range of conventional dating methods. Amino acids in the speleothem were probably derived from surface soils and are associated with brown humic stains in the calcite.
DOI：
10.1098/rspa.1953.0064
发表时间：
1953-01-01
影响因子：
--
作者：
FISHER, R
通讯作者：
FISHER, R