A 220 ka palaeoenvironmental reconstruction of the Fuentillejo maar lake record (Central Spain) using biomarker analysis
A 220 ka palaeoenvironmental reconstruction of the Fuentillejo maar lake record (Central Spain) using biomarker analysis
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DOI：
10.1016/j.orggeochem.2012.11.012
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发表时间：
2013-02
影响因子：
3
通讯作者：
J. Ortiz;Laura Moreno;T. Torres;J. Vegas;B. Ruiz-Zapata;Á. García-Cortés;L. Galán;A. Pérez-González
中科院分区：
文献类型：
--
作者：
J. Ortiz;Laura Moreno;T. Torres;J. Vegas;B. Ruiz-Zapata;Á. García-Cortés;L. Galán;A. Pérez-González
被称为Fuentillejo马尔（西班牙中部）的火山湖的沉积记录提供了机会，以确定在中更新世和上更新世的伊比利亚半岛的中南部的古环境演变。共439个样品，从88米的ca。142米长的核心（跨越最后一个ca。355 ka）进行了检测。这段时间相当于最后220 ka的记录。高的正构烷烃CPI值和硫的存在表明，几乎没有发生成岩信号衰减或修改。许多基于正构烷烃的指数（例如，主要的正烷烃、ACL、Paq和TARHC比率，以及C27、C29和C31正烷烃相对于C27 + C29 + C31总和的比例）烷烃，表明随着时间的推移，进入玛珥湖的有机质的条件发生了变化，其中包括陆地植被的主要输入，与藻类或陆生植物、水生植物和藻类的混合输入的其它植物交替出现。C27，C29和C31的比例是有用的重建盆地的古环境演变，因为它们允许分配几个干燥的间隔，在此期间，草的发展，而在潮湿的阶段，树木扩大在牺牲草。总的来说，我们发现这些事件与格陵兰和南极洲冰芯以及海洋冰芯中δ 18 O记录中观察到的气候周期之间有很好的对应关系。因此，我们可以得出结论，全球古气候变化记录在马尔记录。同样，海因里希事件似乎反映在正构烷烃指数中。用7月21日北纬65 °的日射曲线进行单谱分析和交叉谱分析，证实了这一点。该方法显示，在Fuentillejo记录（103，41，23和19 ka）解释的周期显示的轨道影响的证据有关的天文周期的偏心率变化在地球轨道，地球的轨道振荡，和岁差变化（米兰科维奇理论）。
The sedimentary record of the volcanic lake known as the Fuentillejo maar (central Spain) offers the opportunity to determine the palaeoenvironmental evolution of the central-southern part of the Iberian Peninsula during the Middle and Upper Pleistocene. A total of 439 samples from the upper 88 m of a ca. 142 m long core (spanning the last ca. 355 ka) were examined. The interval corresponds to the last 220 ka of the record. High n-alkane CPI values and the presence of sulfur revealed that little diagenetic signal attenuation or modification had occurred. A number of n-alkane-based indices (e.g. predominant n-alkane, ACL, Paq and TARHC ratios, and the proportion of C27, C29 and C31 n-alkanes with respect to the summed C27 + C29 + C31) alkanes, showed changing conditions in the organic matter input to the maar lake over time, with episodes involving a major input of terrestrial vegetation, alternating with others in which algae or a mixed input of terrestrial plants, aquatic macrophytes and algae occurred. The proportions of C27, C29 and C31 were useful for reconstructing the palaeoenvironmental evolution of the basin as they allowed assignment of several dry intervals during which grasses developed, while during humid phases trees expanded at the expense of grasses. In general, we found good correspondence between these episodes and the climatic cycles observed in δ18O records from ices cores in Greenland and Antarctica, as well as from marine cores. Thus, we conclude that global palaeoclimatological changes were recorded in the maar record. Likewise, Heinrich Events appeared to be reflected in the n-alkane indices. This was confirmed by single spectral analysis and cross spectral analysis with the insolation curve on 21 July at a latitude of 65°N. The approach revealed that the cycles interpreted in the Fuentillejo record (103, 41, 23 and 19 ka) showed evidence of orbital influence related to the astronomical cycles of the eccentricity variation in the Earth’s orbit, the Earth’s obliquity oscillation, and the precession variation (Milankovitch theory).