【作者】 孙佳；

【导师】 李文渊；

【作者基本信息】 长安大学 ， 构造地质学， 2010， 硕士

【摘要】 日月山-化隆超基性岩带位于南祁连造山带。自20世纪70年代后期以来发现了拉水峡铜镍硫化物矿床,使这一地区逐渐成为国内外地质学家关注的焦点。本文依托国土资源大调查项目“青海省化隆县甘都地区铜镍矿调查评价”,选取日月山-化隆成矿带中比较有代表性的亚曲岩体,通过对亚曲岩体岩石学、矿物学、主量元素、微量元素及硫同位素、Re-Os同位素地球化学等方面的系统研究,取得了以下主要认识：1.亚曲岩体属镁铁-超镁铁岩类,主要的岩石类型有角闪石化辉长-苏长岩、石英闪长岩、黑云母辉长岩,超基性岩数量少,主要含矿岩相为辉长—苏长岩和闪长岩,各岩相带为同源岩浆结晶分异演化的产物；主要的造岩矿物有辉石、斜长石、角闪石及黑云母。2.亚曲岩体的稀土元素表现为轻稀土富集型,具有比较明显铕负异常,富集大离子亲石元素,相对亏损高场强元素。3.岩浆源区为富集的岩石圈地幔,源区物质受到沉积物质的交代改造。形成于440.74±0.33Ma。4.形成岩体的大部分岩浆已经不是原生岩浆,而主要是由演化程度不同的岩浆组成,岩浆在上升过程中受到过地壳物质的混染。硫同位素、铼-锇同位素特征结合岩石化学资料显示亚曲岩体在岩浆演化过程中发生了辉石、斜长石等矿物的分离结晶作用及富硅组分地壳围岩的混染可能是引起该矿床母岩浆硫饱和与硫化物发生熔离作用而成矿的主要因素。更多还原

【Abstract】 Riyue-Hualong ultrabasic rocks lies in the southern part of Qilian orogenic belt. Since the th late 70s of 20th century, after we found the Lashuixia copper-nickel sulfide deposit, this region has become the focus of domestic and foreign geologists. In Riyue-Hualong rock band, Yaqu rock is more representative. This paper according to systematically research the petrography, crystal chemistry, rare earth elements, trace elements and S and Re-Os isotopic geochemistry of Yaqu rock body, scientifically demonstrates its magmatic process, magma nature and mantle source district features. Based on these researches we get some initial understanding as follows:1. The Yaqu intrusion is mafic-ultramafic rocks,the main rock types are amphibole gabbro-norite, quartz diorite, biotite gabbro, the quantity of ultrabasic rock is few, the main ore-bearing rocks are gabbro-norite and diorite, each lithofacies is the result of mineral crystal by the same source magma; the main rock-forming minerals are pyroxene, plagioclase, hornblende and biotite.2. The REE partitioning pattern is LREE enrichment, the Eu anomaly is a distinct negative, and enriches LILE, correspondingly depleted HFSE.3. The magma source is enriched mantle, and the source matter is composed by metasomatic lithosphere mantle matter. Its formation age is 440.74±0.33 Ma.4. A majority of magma which forms the rock body is not the primary magma, it mainly composed by different evolution degree magma, When the magma is in the course of rising it should be hybridized a little by the crust substance. The S isotop,Re-Os isotope geochemical character and petrochemical data show that crustal contamination and the fractionation of pyroxene and Plagioclase in the magma revolution process of Yaqu intrusion and the accession of silicon-rich crustal rock composition may be the main factors leading to S-saturation and sulfide segregation in deep crust.更多还原