越南北部岩溶特征及其相关环境问题

CHARACTERISTICS OF KARST IN NORTHERN VIETNAM AND ITS RELEVANT ENVIRONMENTAL PROBLEMS

越南北部属热带季风气候，受东南亚季风影响明显，雨量充沛，气温高，植被发育。它们地处特提斯海槽和环太平洋带两个全球性的构造带交汇处，碳酸盐岩受构造改造强烈，岩溶广泛发育，岩溶地貌类型齐全。与中国西南亚热带、热带岩溶区相比，岩溶发育特征有许多类似之处，但其岩溶泉水有更高的碱度，反映出更强烈的溶蚀作用。随着越南经济发展，岩溶区中的一些环境问题也日益突出，不合理的土地利用，已开始造成土地石漠化等环境问题。

Northern Vietnam is controlled by a humid tropical climate which is heavily influenced by Southeast Asia monsoon, and characterized by rich rainfall and high temperature. This area is located at the juncture of two active tectonic belts: the Mediterranean (Tethys) and the Circumpacific in global scales. The carbonate rocks in this area suffered from different neotectonic movements. Therefore, the karstification in this region is benefited from such local conditions. The karst features in Vietnam are quite similar with those of south China, but it also enjoys its unique characteristics. Vietnam depends more and more on the resources in karst areas for its development, but unreasonable land uses have led to some environmental problems.