Climate-induced changes in Holocene calcareous tufa formations, Bohemian Karst, Czech Republic
Climate-induced changes in Holocene calcareous tufa formations, Bohemian Karst, Czech Republic
复制标题
捷克共和国波西米亚喀斯特全新世钙质凝灰岩地层的气候变化
DOI：
10.1016/s1040-6182(01)00107-0
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发表时间：
2002
影响因子：
2.2
通讯作者：
V. Cílek
中科院分区：
文献类型：
--
作者：
K. Žák;V. Ložek;J. Kadlec;J. Hladı́ková;V. Cílek
波希米亚喀斯特是位于布拉格西南部的一个小型喀斯特地区，大约有 70 个最近形成和/或过去形成全新世钙质凝灰岩的地点。所有已知的凝灰岩堆积物都显示出非常相似的岩性和生物地层演化模式，反映了气候变化、侵蚀事件和生物群演替。 Svatý Jan pod Skalou 的 17m 厚的凝灰岩堆积物被选为当地凝灰岩矿床发育良好的典型代表并进行了彻底研究。凝华形成于距今约 9500 年，位于晚冰期/早全新世时代的平坦河流砾石台地。岩性均匀、纯硬多孔凝灰岩的沉积一直持续到距今约 6500 年。从那时起，气候更加不稳定，经历了几次干旱和侵蚀事件，形成了松散凝灰岩与嵌入式土壤和碎石层交替出现的岩性多样的复合体。大约距今 2500 年，凝灰岩沉积终止，随后出现了与凝灰岩体下方泉水迁移有关的部分侵蚀。岩性、软体动物组合以及碳酸盐中氧和碳稳定同位素比率的振荡记录了全新世的气候变化。观察到的模式与整个中欧石灰华沉积物的演化非常吻合。
About 70 localities where Holocene calcareous tufa is formed recently and/or was formed in the past are known in the Bohemian Karst, a small karst area located SW of Prague. All known tufa accumulations display a very similar pattern of lithological and biostratigraphic evolution, reflecting climatic changes, erosion events and biota succession. A 17m thick tufa accumulation at Svatý Jan pod Skalou was selected and thoroughly studied as a typical, well developed representative of local tufa deposits. Tufa formation started at about 9500 BP, on a flat fluvial gravel terrace of Late Glacial/Early Holocene age. Deposition of lithologically uniform, pure hard porous tufa continued until about 6500 BP. From that time, a more unstable climate with several dry periods and erosion events produced a lithologically varied complex of loose tufa alternating with embedded soils and scree layers. Termination of the tufa deposition occurred about 2500 BP, and was followed by partial erosion connected with relocation of the spring below the tufa body. Holocene climatic changes were recorded in lithology, molluscan assemblages, and oscillations of oxygen and carbon stable isotope ratios in carbonate. The observed patterns are in good agreement with the evolution of calcareous tufa deposits throughout Central Europe.