黑龙江东风沟金矿赋矿岩石地球化学特征及其地质意义

东风沟金矿床位于东宁县老黑山晚古生代断陷盆地内。围岩蚀变类型主要为硅化、碳酸盐化、绢云母化和绿泥石化。赋矿岩石地球化学研究表明,赋矿岩石主要为一套英安质、流纹质火山岩,属于高硅、低碱钙碱性系列岩石(σ3.3)。Rb、Ba、K、Pb等大离子亲石元素(LILE)相对富集,Nb、Ta、P、Ti等高场强元素(HFSE)相对亏损;轻稀土元素(LREE)相对重稀土元素(HREE)轻度富集。Nb/Ta值(平均14.7)和Zr/Hf值(26.23~38.37)显示岩浆具有壳源特征,形成于与俯冲带有关的陆缘环境,与库拉板块俯冲关系密切。

Geochemical characteristics and its geological significance of ore-hosting rocks in Dongfenggou gold deposit,Heilongjiang

Dongfenggou gold deposit is located in the Dongning County within the Laoheishan Late Paleozoic rift basin． The wall rock alterations are mainly silicification，carbonatization in type，sericitization and chloritization in type． The research of geochemical of ore- hosting rocks shows that the ore- hosting rocks are mainly a set of the dacitic and rhyolitic volcanics． They are characterized by high silicon，low- alkali，belonging to calcium alkaline rocks (σ ＜3. 3)． The ore- hosting rocks are relatively enriched in large ion lithophile elements (Ｒb，Ba，K，Pb， etc． ) and depletion in high field strength elements (Nb， Ta， P， Ti， etc． )． Light rare earth elements (LＲEE) are lightly enriched，which is relative to heavy rare earth elements (HＲEE)． Nb/Ta ratio (average 14. 7) and Zr/Hf ratio (26. 23 ～38. 37) have the characteristics of crust source，which is formed in the epicontinental environment related to the subduction zone and close to the subduction of Kula Plate．