中国玛珥湖的时空分布与地质特征

自新生代以来 ,在亚洲东部大陆边缘的裂谷系和青藏高原内部及周边地区 ,火山活动频繁发生 ,形成大量火山和火山岩 ,在一些火山区还发育有大小不等、形态不一的玛珥湖 ,其中有的积水 ,有的干枯 ,它们集中分布于雷琼、东北、青藏高原等地区 ,跨越了热带、亚热带、温带和高寒地带。从中新世的山东山旺盆地 ,早更新世东北龙岗地区的龙湾 ,到雷琼地区中晚更新世的田洋、湖光岩等 ,几乎各个时代、各种类型的玛珥和玛珥湖都有 ,玛珥湖中的沉积物从几十米到一二百米厚度不等 ,记录了不同地区、不同时段气候环境演变的历史 ,对全球变化研究有着重要意义。

THE DISTRIBUTION AND GEOLOGICAL CHARACTERISTICS OF MAAR LAKES IN CHINA

Thispaperpresentsageneral report which first gives the distribution and geological characteristics of maar and maar lakes in China. The projects concerning maar lake research have been widely launched during the last decade, particularly within the framework of the EUROMAARS. Maars like a natural gauge recorded paleoclimate changes. The morphological features of maar are important conditions for development and preservation of high resolution archives of paleoenvironmental variations. The well defined and constant catchment basin ensures homogeneity of detritus input, and climate change, which may trigger changes in vegetation,sedimentation pathways with respect to erosion factors, aeolian input and the quality and quantity of organic material. There are many maars from tropical zone to the North Temperate Zone in China.Maar and maar lakes in China are mainly located in three regions: Leiqiong Volcanic Field, Northeast China Volcanic Field and Qinghai Xizang Plateau Volcanic Field. The known oldest maar is distributed in Shanwan area, which formed about 13Ma ago. Maars in Leiqiong Volcanic Field are located in Leizhou Peninsula and the north part of Hainan Province. Maar lakes such as Huguangyan and Shuangchiling maar lakes wereformed during Shimaoling epoch and Huguangyan epoch. These maar lakes are located in tropical area with intense monsoon and typhoon activities. Some researchers suggest that tropical forcing is a stronger influence on global changes. However, the continuous high resolution record is scarce in the tropical region in China. These maar lakes provide detailed information of paleoclimatic and paleoenvironmental changes at least during the past 400000 years. There are about 164 volcanic cones, craters and maars distributed in Northeast China Volcanic Field. Generally, maars are concentrated in Huinan county and Jingyu county, Jilin Province. The K Ar ages from the basal of maars are between 2.13Ma and 0.96Ma. But some maars may be younger than 0.96Ma from geomorphological opinion. Maars in Qinghai Xizang Plateau Volcanic Field are mainly distributedinMts.West Kunlun and Kekexili. According to interpretation of satellite photograph and aerophotograph, some maar lakes are perfectly preserved in this area. Qinghai Xizang Plateau is the highest and largest plateau in the world and not only affects Asian Monsoon and Westerlies, but also has an important effect to global climate. The archieves in maar lakes may help scientists to discuss the uplift of the plateau. MaarandmaarlakesinChinacoverdifferentgeological and environmental background.They provide the abundat information of paleoclimate and paleoenvironment. The result from these maars will have great contribution to global changes.$$$$