川黔地区地表钙华中发现现代淡水叠层石及藻席

Present Freshwater Stromatolites and Algal Mats in Surface Calcareous Tufa in the Sichuan and Guizhou Areas

笔者通过对四川九寨沟、贵州黄果树、马岭河峡谷以及香纸沟的地表钙华的考查和研究,首次在地表钙华体中发现现代淡水叠层石及其藻席。并总结了研究区叠层石藻席的种类和特征。认为该研究区叠层石藻席中微生物群落的优势种主要属于蓝藻门中的裂须藻属(Schizothrix)、席藻属(Phormidium)和鞘丝藻属(Lyngbya)。该叠层石的形成是由于蓝藻藻席的新旧更迭以及沉积物的周期性沉积造成的;叠层石的纹层和形态可能与蓝藻的属种及叠层石的生长环境有关。笔者认为,现代钙华淡水叠层石及其藻席的研究将对沉积学、地球微生物学、叠层石及其成矿学、喀斯特地貌演化以及水文气候等方面的研究有着重要的理论意义。

Based on systematic surveys and laboratory research of the surface calcareous tufa in Ji-uzhaigou of Sichuan, and Huangguoshu, Malinghe gorge and Xiangzhigou of Guizhou, it is first found that there are present freshwater stromatolites and their algal mats in surface calcareous tufas. A lot of bibliographies are investigated and reviewed in order to identify some calcareous tufas with stromatolites in the paper. All the stromatolitic algal mats in research areas are summarized according to their varieties and features. It is considered that dominant species of microbio-coenosis in these stromatolite algal mats are mainly Schizothrix, Phormidium and Lyngbya belonging to cyanophyta. Formation of the freshwater calcareous tufas stromatolites result from laminated construction of cyanophyta mats and periodic calcareous deposition. Layers and other morphology of the stromatolites are related to species of cyanophyta and the living environment of stromatolites. Research on these present freshwater stromatolites and their algal mats in surface calcareous tufas is considered to be important to the study of sedimentology, geomicro-organism, stromatolites and their mineralizations, karst geomorphology and hydrology and climate.