福建三明万寿岩层状洞穴发育过程及其工程地质意义

万寿岩位于三明市西17 km的岩前盆地，是一座圆锥状灰岩孤峰，地理坐标26°16'13″N，117°29'37″E。孤峰上发育两层水平洞穴，上层洞穴以灵峰洞为代表，下层洞穴以船帆洞为代表，其中灵峰洞是在福建及东南沿海地区发现的第一个旧石器时代早期洞穴文化遗址，船帆洞内遗存的距今3万年左右的人工石铺地面对研究末次冰期古代人类生存环境和文化演进有重大意义。两级层状洞穴和区内的两级河流阶地显示万寿岩地区从中更新世晚期以来至少经历了4次隆升，262 ka前为第1隆升期，185~37 ka为第2隆升期，37.0~17.4 ka为第3隆升期，10.4 ka以来为第4隆升期；前两个间歇期内分别形成了灵峰洞和船帆洞。262~185 ka，灵峰洞从岩溶管道逐渐扩大增宽形成洞厅，期间灰岩的溶蚀速率为0.19 mm/a；37.0~17.5 ka，船帆洞逐步从岩溶管道形成洞厅及现状规模，期间灰岩的溶蚀速率为0.36 mm/a。区内新构造运动的特征和船帆洞以下未被探明的溶洞以及层状洞穴的发育过程表明，船帆洞存在底板坍塌的可能性。因此，对船帆洞的保护措施除现有的防止洞顶坍塌及防渗处理外，更应考虑对船帆洞现有底板保护，避免下层洞穴的岩溶作用引起底板坍塌。

Development process of layered karst caves and its implication of engineering geology,Wanshouyan, Fujian Province

Wanshouyan is a trochiformis isolated peak of limestone, and located in Yanqian Basin(26°16'13″N, 117°29'37″E) which is 17 km from western Sanming City. There are two stages of layered caves in the isolated peak, the upper and lower caves are represented by Lingfeng cave and Chuanfan cave respectively. Lingfeng cave is the first Lower Paleolithic cave site in Fujian Province even the coastal areas in Southeast of China, and the artificial pebble-paved ground 30 ka ago in Chuanfan cave is significance for living environment and cultural evolution of ancient human in the Last Glacial period. Two stages of layered caves and two stages of river terraces in the study area suggested the Wanshouyan area has undergone at least four phases of uplifting since the late Middle Pleistocene. The first phase is before 262 ka; the second phase is 185~37 ka; the third phase is 17.4~12.0 ka, and the fourth phase is 10.4 ka to the present. Lingfeng cave and Chuanfan cave formed in 262~185 ka and 37.0~17. 5 ka respectively, while the dissolution rate of karst was 0.19 mm/a and 0.36 mm/a. It indicate that the floor of Chuanfan cave exist a possibility of collapse according to characteristics of multi-stage crustal uplifting since the late Middle Pleistocene, undiscovered cave under Chuanfan cave and development process of layered karst caves. More attention should be taken on the protection of floor in Chuanfan cave apart from existing protective measures, and the floor may collapse by the development of layered karst caves.