New data on sedimentation in the Mawoshan Karst Basin of Northwest Guizhou Province
Zhang Xinbao
1. Key Laboratory of Mountain Environment Evolution and Regulation, Institute of Mountain Hazards and Environment, Chengdu, Chinese Academy of Sciences, 610041, Chengdu; 2. Puding Karst Ecosystem Observation Research Station, 562100, Puding, Guizhou: China
Abstract:This paper provided new data on recent environment changes and 137 Cs depth distributions in the Mawoshan Karst Basin to reply the paper on “ Recording of soil sediment in the Mawoshan Karst Basin of Northwest Guizhou Province冶from Mr. Wu Pang. New data indicated that: 1) The Mawoshan Karst Basin was not continuous lake environment before 1970s. As the sink hole was blocked, the lower part of the basin was impounded and became a lake in 1958. The lake was drained and returned to farming land when a drain tunnel was dug out in 1973. 2) Spatial variations of 137 Cs depth distributions over the basin were similar between this paper and Mr. Wu Pang爷s paper. The major differences of 137Cs depth distributions in the three cores of the lower part of the basin between the two papers were : except for a few layers in the middle and lower parts of the profile containing 137 Cs with concentrations mostlygreater than 2 Bq/ kg, the rest layers contain little 137Cs in his paper, however, except for a few layers in the middle and lower parts of the profile containing little 137 Cs, the rest layers contain 137 Cs with concentrations mostly less than 2 Bq/ kg in this paper. As the type and model number of detector,delectability, counting sample weight, counting time and analytical precision were not described in Mr Wu’s paper, the reasons for the differences of 137 Cs concentrations of the layers in the cores were not discussed between the two papers.