A multiproxy palaeolimnological investigation of Holocene environmental change, between c. 10 700 and 7200 years BP, at Holebudalen, southern Norway
A multiproxy palaeolimnological investigation of Holocene environmental change, between c. 10 700 and 7200 years BP, at Holebudalen, southern Norway
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对全新世环境变化的多代理古湖泊学调查
DOI：
10.1177/0959683608089217
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
Melanie J. Leng
中科院分区：
文献类型：
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作者：
V. Panizzo;Vivienne J. Jones;H. J. B. Birks;John Boyle;Stephen J. Brooks;Melanie J. Leng
利用地球化学分析（x射线荧光、δ13C和C/N比值）重建了挪威南部Holebudalen附近一个小湖泊的早全新世环境（10685 ~ 7260 cal. yr BP）。结果表明，随着流域冲水量的减少（由钛和钾矿物显示），植被稳定和水生生产力（C/N比）的增加，一段时期的稳定性增加。然而，不稳定时期（点火损失（LOI）下降）也被观察到（最明显的是在约9060 cal. yr BP）。chironomid推断的七月温度（CI-T）重建显示，在c. 8400至8000 cal. yr BP之间冷却了c. 2°c (RMSEP = 1.0°c)，因此在8675至7830 cal. yr BP之间进行了高分辨率（5毫米；c. 20年）硅藻分析，以进一步研究这一变化。在约8270 ~ 8000 cal. yr BP之间，浮游硅藻（如Aulacoseira种）的丰度大幅减少（约50%），而周围硅藻群落（如Navicula pupula， Pinnularia mesolepta）的丰度绝对增加。多代理分析表明，在一段时间内，湖冰覆盖增加，湍流减少。硅藻区系的变化伴随着LOI百分比的下降和流域侵蚀的增加，以及全新世早期区域气候扰动的其他证据。因此，在Holebudalen的全新世早期变暖趋势的叠加上，存在气候扰动，例如在约8200至8000 cal. yr BP之间，硅藻群落反映了气候扰动。
Geochemical analyses (x-ray fluorescence, δ13C and C/N ratios) were used to reconstruct early Holocene environments (between 10685 and 7260 cal. yr BP) at a small lake near Holebudalen, southern Norway. Results show a period of increasing stability, with reduced catchment inwash (shown by titanium and potassium minerals), vegetation stabilization and increasing aquatic productivity (C/N ratios). However, periods of instability (loss on ignition (LOI) decrease) are also seen (most notably at c. 9060 cal. yr BP). Chironomid-inferred July temperature (CI-T) reconstructions show a cooling of c. 2°C (RMSEP = 1.0°C) between c. 8400 and 8000 cal. yr BP and so high-resolution (5 mm; c. 20 yr) diatom analyses were conducted between 8675 and 7830 cal. yr BP in order to further investigate this change. Between c. 8270 and 8000 cal. yr BP there were large reductions (> 50%) in the abundance of tychoplanktonic diatoms (eg, Aulacoseira species) and absolute increases in periphytic diatom communities (eg, Navicula pupula, Pinnularia mesolepta). The multiproxy analyses suggest a period of increased lake ice cover with associated reductions in turbulence during this time. Diatom flora changes are concomitant with a fall in percent LOI and increased catchment erosion at the site and other evidence of regional climatic perturbations in the early Holocene. Therefore, superimposed upon an early Holocene warming trend at Holebudalen, there are climatic perturbations, for example reflected between c. 8200 and 8000 cal. yr BP by diatom communities.