泰国西部岩溶地貌和水文地球化学特征及其与中国西南岩溶的对比

Karst topography and hydro-geochemical characteristics in western Thailand and their correlation to that in southwestern China

泰国岩溶面积约占中南半岛岩溶面积的1/4,横跨近11个纬度。泰国岩溶作用强烈,地貌奇特,类型多样,既有典型的高原坡立谷岩溶,也有典型的峰丛洼地谷地和滨海峰林岩溶地貌,因而在全球岩溶对比研究中具有重要地位。本文在初步查明泰国岩溶分布、典型岩溶区的水文地球化学特征的基础上,分析了泰国岩溶发育的主要特点和动力条件,并与中国西南岩溶作了对比,旨在推动中国与中南半岛岩溶的对比以及全球现代岩溶的对比研究。

Thailand is situated in the central Indo-China Peninsula.The karst of Thailand is in the same glob-al karst environmental zone as southwest China.Karst study in Thailand is mainly focused on the southern Shan states plateau in the north and Phang Nga bay of Karbi Province in the south.Published work on karst in Thailand has mainly been descriptive in nature,addressing topics such as the relationship between karst landscape development and regional geological structure in Mae Hong Song karst region,and the impact of climate,lithology and structure on coastline tower karst in southern Thailand.As yet,Earth System Science and Karst Dynamics have not been introduced into karst research in Thailand,thus research has not been car-ried out focusing on karst development mechanisms,influence factors. In this paper, the discussion of karst distribution and development, hydrogeological features of typical landscapes and their controlling factors in Thailand could help to promote study of correlations in karst geology between China and Indo-China Peninsula, providing fundamental support for the global karst carbon cycle monitoring network. Thailand has about 50,000 km^2 ,of karst, i. e. , one fourth of the Indo-China Peninsula. Typical karst landscapes are well developed, including plateau polje, peak cluster, peak valley and offshore peak forest. All those landscapes are important in the research field of global karst correlation. Since 2012, an international project in cooperation with the Department of Groundwater Resources of Thailand has been carried out by the Institute of Karst Geology. It is titled ＂Correlation study of karst geology between China and Indo-China Peninsula＂ and supported by China Geological Survey. Survey data indicates that karst in Thailand is mainly located in the west part in north-south direction, crossing 11 degrees （N19.3° to NS. 5°） of latitude. Various karst landscapes with different hydro-geochemistry are found in the different latitude zone. At present, the first karst hydrogeological and carbon cycle monitoring station was established at Phu Toej spring, Kanchanaburi, Thailand, and high-resolution data was collected at 15-minute intervals for one year, including water temperature, pH, specific conductivity and dissolved oxygen. Compare to typical underground streams or springs in the karst of southwest China, Phu Toej spring has higher Ca^2＋ （100-120 mg/L）, HCO3^- （8.6-9.3 mmol/L） and specific conductivity（700-777 μs/cm）. This indicates that the intensity of karst processes in this catchment is much greater than that in the karst of southwest China, and there is potentially higher karst carbon sink intensity in such a tropical monsoon climate zone.