On the stratigraphic integrity of leaf-wax biomarkers in loess paleosols
On the stratigraphic integrity of leaf-wax biomarkers in loess paleosols
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黄土古土壤中叶蜡生物标志物的地层完整性
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
T. Eglinton
中科院分区：
文献类型：
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作者：
C. Häggi;R. Zech;C. McIntyre;M. Zech;T. Eglinton
黄土-古土壤序列中基于分子代用指标（如叶蜡生物标志物）的古环境和古气候研究是第四纪研究中一条很有前途的研究路线。生物标志物和粉尘的同沉积作用是这类重建的主要前提，近年来这一问题已成为一个有争议的课题。本研究使用两种独立的方法来测试叶蜡生物标志物的地层完整性：（i）在瑞士高原冰碛物的两个沉积深度剖面中定量测定长链正构烷烃和脂肪酸，包括全新世表土和下层B和C层。由于冰川沉积物最初的有机质含量非常低，这些剖面的B和C层位中大量的叶蜡生物标志物将反映沉积后根源或微生物的贡献。(ii)对塞尔维亚“Cr-venka”黄土剖面几个深度段的正构烷烃和正链烷（脂肪）酸进行了化合物特异性放射性碳测量，并将结果与沉积物年龄的独立估计值进行了比较。我们发现极低浓度的植物蜡正构烷烃和脂肪酸的B和C层低于表层土壤的沉积物剖面。此外，化合物特定放射性碳分析得出的植物蜡14 C年龄与已发表的塞尔维亚黄土存款的发光年龄和地层学非常一致。这两种方法证实，沉积后，根衍生或微生物的贡献是可以忽略不计的两个调查系统。奇数和偶数同源物的年龄之间的良好一致性也表明，化石叶蜡的改造和合并也不是特别相关。
Paleoenvironmental and paleoclimate reconstruc- tions based on molecular proxies, such as those derived from leaf-wax biomarkers, in loess-paleosol sequences represent a promising line of investigation in Quaternary research. The main premise of such reconstructions is the synsedimentary deposition of biomarkers and dust, which has become a de- bated subject in recent years. This study uses two indepen- dent approaches to test the stratigraphic integrity of leaf- wax biomarkers: (i) long-chain n-alkanes and fatty acids are quantified in two sediment-depth profiles in glacial till on the Swiss Plateau, consisting of a Holocene topsoil and the underlying B and C horizons. Since glacial sediments are initially very poor in organic matter, significant amounts of leaf-wax biomarkers in the B and C horizons of those pro- files would reflect postsedimentary root-derived or micro- bial contributions. (ii) Compound-specific radiocarbon mea- surements are conducted on n-alkanes and n-alkanoic (fatty) acids from several depth intervals in the loess section "Cr- venka", Serbia, and the results are compared to independent estimates of sediment age. We find extremely low concentrations of plant-wax n- alkanes and fatty acids in the B and C horizons below the topsoils in the sediment profiles. Moreover, compound- specific radiocarbon analysis yields plant-wax 14 C ages that agree well with published luminescence ages and stratigra- phy of the Serbian loess deposit. Both approaches confirm that postsedimentary, root-derived or microbial contributions are negligible in the two investigated systems. The good agreement between the ages of odd and even homologues also indicates that reworking and incorporation of fossil leaf waxes is not particularly relevant either.
与根岩相关的黄土有机质叠印的横向和深度变化 â 通过脂质分子代理和 X 射线断层扫描揭示
影响因子：
6.2
作者：
Gocke M;Peth S;Wiesenberg G.L.B.
通讯作者：
Wiesenberg G.L.B.