On the age of metamorphic rocks of the yudongzi group and the archean crystalline basement of the qinling orogen 鱼洞子群变质岩年龄及秦岭造山带太古宙基底
2.
The geological conditions are very complicated in hejiazhai tunnel which is located in guizhou shuibo railway , this tunnel is named " mashed tunnel " with the most difficult geological conditions such as the high dense gas and developed karst and gushing water assembled together , the geological hazards like the gushing water and sand , the collapse of tunnel , surface subsidence and slide , cracking of tunnel lining were often happened during construction period 摘要贵州水柏铁路何家寨隧道，工程地质条件极其复杂，集“高瓦斯、强岩溶、大涌水”为一体，施工期间曾发生多次涌水涌砂、洞内坍方、地表塌陷与滑坡、支护衬砌开裂变形等地质灾害，堪称水柏铁路施工难度最大的“烂洞子” 。
3.
Dongzigou ag deposit and jianbaoshan au deposit are hosted in the sandstone of middle - proterozoic suberathem , which are developed from the proterozoic sediment metal source - rocks formed during the meso - proterozoic volcanism and reworked by the mesozoic tectono - magmatism during the formation of the metamorphic core complexes in eastern hebei . the dongzigou ag deposit has the characteristics of reformed strata - bound origin , the jianbaoshan au deposit , located in the detachment fault , is the alterated rock type . both deposits have the similar wall - rock alteration , and show the same trace element behavior , and ree patterns . they are the results of the multi - stage tectono - magmatism in the environment of continental extension in eastern hebei region . their mineralization depended on their wall rocks and relative location in metamorphic core complexs 赋存于中元古宙长城系常州沟组的洞子沟银矿床和尖宝山金矿床是由密云-都山变质核杂岩构造体系所控制的一组矿床。其成因为中元古宙火山岩浆活动形成的沉积矿源，后经中生代的变质核杂岩构造岩浆体系叠加改造而成。洞子沟银矿床具有层控迭加改造的特点尖宝山金矿床则具有破碎蚀变岩型矿床的特点。
