新疆塔城结勒迪克增闪长岩体特征及其含矿性

Geochemical characteristics and ore bearing propertiy of Jieledikezeng diorite in Tacheng,Xinjiang

新疆准噶尔盆地西北缘属中亚造山-成矿带,是中国重要的铜多金属成矿带之一,区内侵入岩的成因及含矿性研究,对进一步提高本区地质矿产勘查程度具有重要的现实意义。针对新疆塔城结勒迪克增闪长岩体,在研究其地质特征、矿化赋存特征的基础上,利用其岩石地球化学数据,结合前人的年代学资料,初步探讨了该岩体的岩石成因、构造环境、含矿性及其与成矿作用的关系等,为该区地质找矿提供一些基础参考。新疆塔城结勒迪克增闪长岩序列由灰色细斑闪长玢岩、粗斑闪长玢岩、细-中粒闪长岩和灰白色黑云母石英闪长岩4个侵入期次组成。岩体岩石硅、镁、钾含量低而钠、铝、铁含量高;弱准铝质,为亚碱性系列岩石;富集Rb、Ba、Th等大离子亲石元素,亏损Nb、Ta、Y、Yb等高场强元素;稀土元素含量较低,配分模式呈右倾曲线,为轻稀土元素富集型,具Ce、Eu弱负异常。该闪长岩序列侵入成岩时代为早石炭世末期,形成于岛弧构造环境,属造山前I型科迪勒拉花岗岩,源岩成分可能来自岛弧型火山岩的部分重熔或同源岩浆演化。经对比研究,结勒迪克增闪长岩体内部各侵入期次Au、Ag、Cu、As、Pb等主要金属元素含量较高且浓集程度不同,Cu、Au等成矿元素分异程度较高,反映出区内多金属成矿与该岩体上侵强烈的岩浆热液作用密切相关。该岩体具备形成斑岩型铜矿、热液型金矿的岩浆岩条件。

The northwest margin of the Junggar Basin in Xinjiang belongs to the Central Asia orogenic metallogenic belt,which is one of the important copper polymetallic metallogenic belts in China.The study of the genesis and ore bearing properties of the intrusive rocks in the area has important practical significance for further improving the degree of geological and mineral exploration in the area.Based on the study of its geological characteristics and mineralization occurrence characteristics,Jieledikezeng diorite sequence in Tacheng,Xinjiang,has been systematically sorted and analyzed by using its rock geochemical data.Combined with the previous chronological data,the rock genesis,tectonic environment,ore bearing property and its relationship with mineralization of this rock mass have been preliminarily discussed,providing some basic references for geological prospecting in this area.Jieledikezeng diorite sequence in Tacheng,Xinjiang is composed of four intrusive periods,namely,gray fine-grained diorite porphyrite,coarse-grained diorite porphyrite,fine medium grained diorite and gray white biotite quartz diorite.The rock mass is low in silicon,magnesium and potassium and high in sodium,aluminum and iron;weakly quasi aluminous,subalkaline series rocks;Rb,Ba,Th and other large ion lithophile elements are enriched,while Nb,Ta,Y,Yb and other high field strength elements are depleted;the rare earth content is low,and the distribution pattern shows a right leaning curve.It is a light rare earth enriched rock,There is weak loss anomaly of cerium and europium.The intrusive diagenetic age of the rock mass is the end of the Early Carboniferous,formed in the island arc tectonic environment,and belongs to the pre orogenic I-type Cordillera granite,Its source rocks may be derived from partial remelting of island arc volcanic rocks or homologous magmatic evolution.Through comparative study,the contents of Au,Ag,Cu,As,Pb and other major metal elements in this rock mass at each intrusive stage are relatively high,and its element concentration is different,and the differentiation of copper,gold and other ore-forming elements is relatively high,reflecting that the polymetallic mineralization in the area is closely related to the strong magmatic hydrothermal process of the rock mass.This rock mass has the magmatic conditions for forming porphyry copper deposits and hydrothermal gold deposits.