蒙古国南部曼莱苏木铜金矿区地质特征与找矿远景研究          下载免费PDF全文

王伟  刘继顺  成功 《地质找矿论丛》2015,30(2):215-220

曼莱苏木铜金矿区是蒙古国南部曼莱—曼达赫成矿带上一个新发现的铜金矿区。对曼莱苏木铜金矿区与该成矿带上的欧玉陶勒盖铜金矿床、查干苏布尔加铜钼矿床的分析对比,认为它们具有相同或相似的成矿地质特征,表明曼莱苏木铜金矿区成矿地质条件十分有利,并圈定了乌兰敖包和奥尤特两个成矿远景区。  相似文献   

Zircon ages and geochemical compositions of the Manlay ophiolite and coeval island arc: Implications for the tectonic evolution of South Mongolia     

《Journal of Asian Earth Sciences》2014

Numerous small dismembered ophiolite fragments occur in South Mongolia, but they are very poorly studied. The lack of age data and geochemical analysis hampers our understanding of the Paleozoic tectonic evolution of the region. We conducted detailed studies on the Manlay ophiolitic complex and Huree volcanic rocks south of the Main Mongolian Lineament (MML) to provide some constraints on these rocks. The Manlay ophiolite consists of dunite, harzburgite, pyroxenite, gabbro, plagiogranite, basalt and chert, locally with chromite mineralization in dunite. The gabbro and plagiogranite yielded SHRIMP zircon weighted mean ²⁰⁶Pb/²³⁸U ages of 509 ± 5 Ma and 482 ± 4 Ma, respectively. The basalt and dolerite samples of this complex show enrichment in LREE and LILE and negative Nb, Ta and Ti anomalies, and the chrome spinel from the chromitite lens in the dunite is characterized by high Cr^# and low TiO₂ contents. These features suggest a supra-subduction zone (SSZ) origin for the ophiolitic complex. The Huree volcanic rocks, ranging from basalt to dacite, display enrichment in LREE and LILE, weak Eu anomalies and distinctly negative Nb, Ta and Ti anomalies, consistent with those of typical magmas in a subduction environment. An andesite sample from this arc yielded a SHRIMP ²⁰⁶Pb/²³⁸U zircon age of 487 ± 5 Ma, which is the oldest reliable age for an island arc in South Mongolia. Recognition of an Early Paleozoic ophiolitic complex and a coeval island arc indicates that South Mongolia underwent a period of active volcanism during Late Cambrian to Ordovician. Additionally, the tuff overlying the ophiolitic complex and a granite intruding the ophiolite have SHRIMP zircon U–Pb ages of 391 ± 5 Ma and 304 ± 4 Ma, respectively. Combining the available data, we propose that the Early Paleozoic subduction–accretionary complexes likely constitute the basement of the Late-Paleozoic arc formations and correlate with the Lake Zone in western Mongolia.  相似文献