北祁连西段柳沟峡铁（铜）矿田牙形刺的发现及其地质意义

笔者依据北祁连山西段柳沟峡铁铜矿田原定长城系朱龙关群含铁（铜）矿火山沉积宕系中新发现的牙形刺化石Ｐｈａｋｅｌｏｄｕｓｏｆｆｅｎｕｉｓ（Ｍｕｌｌｅｒ）Ｐｒｏａｃｏｎｔｉｏｄｕｓ；（∈２－３、∈３）和青白口系大柳沟群碳酸盐岩中新发现的Ｔｒｉｐｏｄｕｓ？Ｓｐ（Ｏ１），并与青海郭密寺地区中寒武统黑茨沟群中所发现的牙形刺化石（∈３－Ｏ１）属种相类似而论，认为上述原定地层还有可能重新厘定为寒武一奥陶系和奥陶系。这一发现为研究和恢复北祁连西段区域构造格架及区域构造演化历史提供了早古生代化石依据，对查明铁（铜）矿等的形成环境、总结成矿规律、扩大找矿效果具有较深远的意义。

THE DISCOVERY OF CONODONTS IN LIUGOUXIA IRON-(COPPER) OREFIELD FROM THEWESTERN PART OF NORTH-QILIAN MOUNTAINS AND ITS GEOLOGICSIGNIFICANCE

There exist diffcnent opinions to the st ra tigrapllic era of iron-copper-containillg rock series in the western part of North--Qilian Mot] ntai[ls. Some a uthors attribute them to the Middle-Upper Proterozoic subera and others to the Cambrian-Odovician period. In recent years,Conodonts (Phakelodus of fenuis (Muller). Proacontiodus A and Tripodus?sp), have beed discovered by the authors in iron- (copper-) containing volcano-sediments pre-named Zhulong Group of Changcheng series at Liugouxia iron-copper mining area. This provides fossilevidence for the attribution of stratisrarphicera and has the potential significance to studyingand recovering the regional tectonic frame and evolution history, to finding out of the metallogenic environmecnt of iron- (copper-) deposits and also to summing up the ore-forming regularity as well as to enlarging the prospoctive ore-exploraton possibility.