High-resolution records of location and stratigraphic provenance from the rare earth element composition of fossil bones
High-resolution records of location and stratigraphic provenance from the rare earth element composition of fossil bones
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DOI：
10.1016/j.gca.2006.06.1556
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发表时间：
2006-09-01
影响因子：
5
通讯作者：
Tuross, N.
中科院分区：
文献类型：
--
作者：
Trueman, C. N.;Behrensmeyer, A. K.;Tuross, N.
骨磷灰石作为一种天然的定时取样装置，在约100年的时间尺度内从局部孔隙沃茨中清除微量元素。1-50 ka.骨化石的稀土元素（REE）和U/Th组成反映了重结晶期伴生孔隙水的组成。骨化石的稀土元素组成受稀土元素在孔隙沃茨和颗粒表面之间分配的控制，骨化石的稀土元素组成反映了孔隙沃茨稀土元素组成的时空变化。轻稀土元素优先吸附到颗粒表面，因此，高La/Yb值在许多骨骼从沿海海洋和风成环境中看到的最好的解释释放稀土元素从轻稀土富集颗粒本地孔隙沃茨和随后的固定在重结晶骨。从肯尼亚南部的Olorgesailie组的peclogenically改变的沉积物中回收的骨的稀土元素组成变化的空间尺度小于10米。位置占48%的观察到的变化，骨化学和骨恢复从8个离散的挖掘在同一时间内等效的地层可以分配到他们的挖掘位置与> 70%的准确性的基础上的判别分析的REE，U，Th组成。尽管存在这种层内变化，但从Olorgesailie组内不同地层中发现的骨骼也可以根据其微量元素组成进行区分。从四个地层中发现的骨骼跨越约。0.5百万年被分配到正确的地层，准确率> 90%。在沉积学条件有利的地方，骨化石的微量元素组成可用于检验地层来源和出土骨的埋藏位置，时间分辨率< 10 ka，空间分辨率< 10 m。骨化石的微量元素组成也可用于研究脊椎动物组合的积累历史和重建陆地表面的孔隙水变化。(c)2006爱思唯尔公司All rights reserved.
Bone apatite acts as a natural, timed sampling device, scavenging trace elements from local pore waters over timescales of ca. 1-50 ka. The rare earth element (REE) and U/Th composition of fossil bones reflects associated pore water compositions during the period of recrystallisation. The REE composition of fossil bones is controlled by partitioning of REE between pore waters and particle surfaces, and the REE composition of fossil bones reflects the REE composition of pore waters which vary spatially and temporally. Light REE are preferentially sorped onto particle surfaces, thus the high La/Yb values seen in many bones from coastal marine and aeolian environments are best explained by release of REE from light REE-enriched particles to local pore waters and subsequent immobilisation in recrystallising bones. The REE compositions of bones recovered from peclogenically altered diatomite sediments of the Olorgesailie Formation of southern Kenya vary over spatial scales of less than 10 m. Location accounts for 48% of the observed variation in bone chemistry and bones recovered from eight discrete excavations within the same time-equivalent stratigraphic layer can be assigned to their excavation location with > 70% accuracy based on a discriminant analysis of REE, U, and Th composition. Despite this within-layer variation, bones recovered from different stratigraphic horizons within the Olorgesailie Formation can also be distinguished on the basis of their trace element composition. Bones recovered from four stratigraphic horizons spanning ca. 0.5 million years were assigned to their correct stratigraphic layer with > 90% accuracy. Where sedimentological conditions are favourable, the trace element composition of fossil bone may be used to test stratigraphic provenance and burial location in excavated bone with a temporal resolution of < 10 ka and a spatial resolution of < 10 m. The trace element composition of fossil bone may also be used to investigate the accumulation history of vertebrate assemblages and to reconstruct pore water variability across land surfaces. (c) 2006 Elsevier Inc. All rights reserved.