CAJ | 학술논문

南北沟岩体位于柴达木地块北缘，出露面积4．5 km2.岩石主要类型有淡色辉长岩、辉长岩、暗色辉长岩，各岩石类型之间多为过渡关系，局部呈侵入接触.主量元素化学组成属拉斑玄武岩系列.岩石相对富集大离子亲石元素，亏损高场强元素，明显亏损 Nb、Ta.岩体原生岩浆属于高镁拉斑玄武岩(Mg O质量分数为11．1％)，在岩浆演化过程中遭受了一定程度中—上地壳物质的同化混染作用.岩体形成于古岛弧环境，是早古生代柴达木地块向祁连地块俯冲过程的产物.从岩浆分异程度、原生岩浆性质、同化混染等方面综合评价认为，南北沟岩体具有较好的铜镍硫化物矿床成矿潜力.
남북구암체위우시체목지괴북연，출로면적4．5 km2.암석주요류형유담색휘장암、휘장암、암색휘장암，각암석류형지간다위과도관계，국부정침입접촉.주량원소화학조성속랍반현무암계렬.암석상대부집대리자친석원소，우손고장강원소，명현우손 Nb、Ta.암체원생암장속우고미랍반현무암(Mg O질량분수위11．1％)，재암장연화과정중조수료일정정도중—상지각물질적동화혼염작용.암체형성우고도호배경，시조고생대시체목지괴향기련지괴부충과정적산물.종암장분이정도、원생암장성질、동화혼염등방면종합평개인위，남북구암체구유교호적동얼류화물광상성광잠력.
Nanbeigou intrusion is located in the northern margin of Qaidam massif,and the outcrop area is 4.5 km2 .The intrusion is emplaced into amphibole plagiogneiss from Paleoproterozoic Dakendaban Group and amphibolite from Mesoproterozoic.It consists of pale gabbro,gabbro,melagabbro. They extend mainly gradual transition,and part shows intrusive contact.Rock alteration is strong,most of pyroxenes alter to amphibole,and part shows biotitization and chloritization;plagioclase shows saussuritization at different levels.Chemical composition of major element belongs to tholeiitic series.The rocks relatively enrich in large ion lithophile element (LILE), deplete in high field strength element (HFSE),and obviously deplete in Nb and Ta.The primary magma of intrusion is high Mg tholeiitic (mass fraction of MgO is 1 1??1%),and is developed by the middle-upper crustal assimilation contamination in a certain extent during the magma evolution.The intrusion,which forms in ancient island arc environment,is the product of Qaidam massif subduction to Qilian massif in Early Paleozoic. According to the degree of magmatic differentiation,characteristics of primary magma and assimilation contamination,it is comprehensively concluded that Nanbeigou intrusion has good metallogenetic potentiality of Cu-Ni sulfide deposit.