甘肃德勒诺尔铁矿地质特征及找矿方向

德勒诺尔铁矿是近年新发现的大型磁铁矿床,位于祁连山造山带中祁连陆块。铁矿体赋存于蓟县系泥硅质板岩中,矿体呈层状产出,与围岩整合接触,矿石主要为变余结构、条带状构造,矿石矿物为磁铁矿,具有沉积变质特征。该矿床的发现对在中祁连地区寻找同类型矿床具有一定的指导意义,同时也填补了该区铁矿勘查找矿空白。     

从磁异常探讨德勒诺尔铁矿构造对矿体的控制作用

德勒诺尔铁矿赋矿地层形成时代为中元古代,其后经历过多期多次构造叠加作用,变形变质作用较为复杂。成矿期后的断裂、褶皱、节理等构造十分发育,受褶皱和断裂构造的影响,矿体的空间形态和产状极其复杂,给钻探工程部署造成很大困难。本文在地面磁测数据处理、转换及构造增强的基础上,对其所蕴含的深部构造信息进行了提取和解释,初步建立起了矿区的基本构造格架,揭示了不同期次、不同方向、不同性质的构造对矿体的控制作用,较好地解决了矿体形态复杂的找矿难题,有效提高了钻探工程的见矿率。     

Petrogenesis and tectonic significance of the early Paleozoic Delenuoer ophiolite in the Central Qilian Shan,northeastern Tibetan Plateau

The newly discovered early Paleozoic Delenuoer ophiolite, in the western margin of the Central Qilian Shan, is composed of serpentinized peridotite, cumulate gabbro, diabase, massive basalt, and pillow basalt. This study presents geochronological and geochemical data for the cumulate gabbro and basalt. LA–ICP–MS U–Pb dating of zircons from the cumulate gabbro yielded a magmatic crystallization age of 472 ​± ​4 ​Ma. The basalts have normal mid-ocean ridge basalt (N-MORB) compositions and a narrow range of ε_Nd(t) values (+4.5 to ​+5.3), which indicates they were derived from a depleted mantle source. On the basis of regional geological constraints, it is proposed that the Delenuoer ophiolite is a westward extension of the South Ophiolite Belt (Yushigou–Youhulugou–Donggou–Dongcaohe Ophiolite Belt) in the North Qilian Shan. The Delenuoer ophiolite, along with the Gulangxia–Delenuoer fault, defines the westernmost part of the tectonic boundary between the North and Central Qilian Shan. This ophiolite may have formed during southward subduction of the Qilian Ocean slab during the early Paleozoic.     

浅析肃北县德勒诺尔铁矿区的构造特征

德勒诺尔铁矿受祁连山长期造山运动影响,使区内构造错综复杂。德勒诺尔铁矿区构造分为SN向挤压应力作用下形成的近EW向构造;NE—SW南西向挤压应力作用下产生的NW向构造;EW向应力松弛拉张作用下形成的一系列张性构造。通过对肃北德勒诺尔铁矿构造特征研究,以期对该矿区后期找矿工作提供重要依据。