Characteristics of annual laminate gray level variations in a stalagmite from Shihua Cave, Beijing and its climatic significance (II)

摘要

The annual laminate gray level variations in the stalagmite TS9501of Shihua Cave, Bei- jing are studied in detail. The environmentalfactors influencing the laminae gray level are also analyzed. Thefollowing conditions may be necessary to the study on the lamina graylevel. A) The seasonal differences of climate in the studied area arestrong. B) The cave has a rapid and simple hydrological connectionwith the surface, such that the gray level variation is great;therefore, cli- matic changes can be more clearly recorded in astalagmite. C) No water from other sources due to lateral flow addsto the seepage over the cave. D) There are move organic impuritiesthan inor- ganic ones, whose content changes distinctly with time inthe samples.