川西北岷山灰岩区喀斯特堰塞湖形成中的生物作用

ON BIO-EFFECTS ON THE DEVELOPMENT OF KARST DAMMED LAKES IN LIMESTONE AREAS, MINSHAN MOUNTAIN RANGE, NW SICHUAN

川西北岷山灰岩区内的喀斯特堰塞湖是一种特殊的湖泊地貌类型,它是在一定的地质地貌条件及水化学条件下由生物作用参与并促进生物型灰华的快速沉积并堰塞河道而成。野外沉积构造和湖泊形态观察、水化学分析及室内对灰华体的光学显微镜和扫描电镜的观察结果表明,生物作用以多种方式存在着。多种生物(苔藓、藻类、灌草丛等)在生物型灰华堤堰的形成(也即喀斯特堰塞湖的形成)过程中的不同生物作用(包括同化作用、拦截作用、毛管作用、捕获粘结作用及构架作用)贯穿于灰华沉积的复杂循环过程之中。

The karst dammed lakes in limestone area of Minshan Mountain Range, NW Sichuan, belong to a special kind of lake morphology. They developed and were formed under certain geological, geomorphological and hydrochemical conditions with bio-effects as result of rapid tufa dam gradation in stream channel. With field observation on the sedimental structure, lake morphology and water chemistry as well as optical & Scanning Electronic Microscopic observation on tufa samples from the research area, various kinds of hip-effects have been identified to exist in the process of tufa dam formation. It is shown in the general cycle model proposed in this paper that many organisms (mosses, algae and bushes etc.) with various effects (assimilation, interception, capillary effect, trapping & binding, and shoring effect) on tufa deposition play an important role throughout the compound cycle process of tufa dam gradation (i. e. the formation of karst dammed lakes) in the stream channels in the research areas.