滇西北衙地区热水岩溶作用及其伴生的地质灾害

报道了滇西北衙地区新发现的热水角砾岩及其显示的热水岩溶与伴生地质灾害的特征。北衙地区热水角砾岩和热水岩溶可分为 4种类型和层次,即①地表相爆发-沉积作用形成的沉积凝灰-角砾岩、热水沉积鲕状灰岩与钙华胶结角砾岩;②与近地表洞穴沉积和垮塌作用有关的热水沉积砾岩和汽爆射流角砾岩;③与热水通道相蚀裂和爆破角砾化作用有关的网络状灰岩角砾岩筒和热水隐爆角砾岩筒;④深部相热水浸煮-蚀变灰岩。除深部相浸煮蚀变作用外,其余 3种热水岩溶作用都可伴生和引起地质灾害。万洞山-五里排一带呈席状覆盖于第三系河湖相的砂砾岩和粘土沉积之上的灰岩质热水角砾岩为一套从陈家庄角砾岩筒滑覆过来的热水角砾岩滑体,其可能是造成金沙江古河道淤塞并使古金沙江改道和形成大拐弯的主要原因。

HYDROTHERMAL KARST AND THEIR ASSOCIATED GEOLOGICAL DISASTERS IN THE BEIYA AREA,WESTERN YUNNAN PROVINCE

This paper reports the characteristics of hydrothermal breccia discovered recently, their hydrothermal karst as well as associated geological disasters in the Beiya area, western Yunnan province. The hydrothermal breccia and karst in the Beiya area are divided into 4 types and zones, including: ① sedimentary tuff and breccia induced by hydrothermal explosion and sedimentation on land surface; ② hydrothermal sedimentary conglomerate and gas-explosive ejecting breccia related to sedimentation in and collapsing of some shallow karst caves; ③ netted hydrothermal limestone breccia and hydrothermal explosive breccia pipe related to hydrofracturing, corrosion and explosion in the hydrothermal channels; and ④ yellow granular limestone formed by simmering and alteration in the deep heated water reservoir. Except the simmering in deep area, other three kinds of hydrothermal karst would associate and induce geological disasters. The hydrothermal limestone breccia sheet presented over Tertiary fluvial, lacustrive sandstone and mud in the Wandongshan-Wulipai area is a hydrothermal breccia landslide from the Chenjiazhuang breccia pipe, and it may be a domain origin which would have obstructed the Jinshajiang old channel and made the Jinshajiang river to change and to form the famous valley and turns.