本文選題：黃鐵礦 + 掃描電鏡��； 參考：《巖石學報》2017年03期

【摘要】：坡仔營鉬礦是欽-杭成礦帶南段最重要斑巖型礦床之一。該礦床發(fā)育典型"中心式面型蝕變"和A、B和D三種類型礦化脈。為了加深對其成礦過程的認識,本研究選取不同礦脈中黃鐵礦,通過掃描電鏡(SEM)、X射線粉晶衍射(XRD)和激光拉曼光譜(Raman),研究其微組構(gòu)標型特征,以期反演成礦過程的熱力學及動力學信息。SEM結(jié)果顯示,A脈內(nèi)黃鐵礦較少,呈100~200μm半自形-他形,籽晶呈扁平乳滴狀;B脈黃鐵礦強烈發(fā)育,呈500~1000μm自形-半自形,籽晶呈近橢圓形層狀;D脈內(nèi)黃鐵礦呈立方體產(chǎn)出,粒度10~20mm左右,三組相互垂直晶紋發(fā)育,籽晶棱角狀線形展布。A脈→B脈→D脈中黃鐵礦粒度逐漸變大,籽晶更加規(guī)則,指示成礦早期至晚期,黃鐵礦結(jié)晶速度逐漸變緩,成生環(huán)境趨于穩(wěn)定。XRD結(jié)果展示,各樣品譜線均發(fā)育著多組黃鐵礦特征峰,但其強峰發(fā)育存在差異。A脈最強峰為28.5°,次強峰37.1°;B脈和D脈相應峰位分別為37.1°、33.1°和33.1°、56.3°。衍射峰型特征表明,A脈樣品晶形應以(1 1 1)面組成的正八面體單形為主,其次為(2 1 0)晶面組成的五角十二面體,其成生溫度應大于300度;B脈樣品應以(2 1 0)組成的五角十二面體單形為主,其次為(1 0 0)晶面組成的立方體單形,形成溫度應介于200~300℃之間或略大;D脈樣品主要以(1 0 0)晶面組成的立方體為主,其形成溫度應小于200℃。Raman光譜揭示,A脈樣品的νEg=348.0~350.7cm~(-1)、νAg=385.2~386.5cm~(-1)、νTg=441.9~422.8cm~(-1),與之相比,B脈和D脈的對應值分別向低頻偏移2~6cm~(-1)和5~14cm~(-1);A脈樣品的散射強度IEg=388.8~745.5、IAg=1532.8~2071.8、ITg=238.9~254.4,而B及D脈樣品的散射強度依次明顯增強。自A脈→B脈→D脈,拉曼位移向低頻偏移,散射強度依次增強,指示三者的成生壓力依次降低。本研究認為,坡仔營斑巖型鉬礦的成生早期為一個高溫、高壓巖漿熱液活動為主階段,隨著成礦溫度、壓力的降低,成礦系統(tǒng)氧逸度逐漸降低,硫及金屬元素逐步轉(zhuǎn)變?yōu)榻饘倭蚧镄问蕉傻V。
[Abstract]:Pozaiying molybdenum deposit is one of the most important porphyry deposits in the southern segment of Qinghang metallogenic belt. There are three types of mineralization veins in this deposit: central surface alteration and AZB and D. In order to better understand the metallogenic process of pyrite in different veins, the microfabric characteristics of pyrite were studied by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and laser Raman spectroscopy (Ram). The thermodynamic and kinetic information of the ore-forming process can be retrieved. SEM results show that there is less pyrite in the vein, 100 ~ 200 渭 m semiautomorphism, and the seed crystal is strongly developed in the flat emulsion drop B vein, and in the 500 ~ 1000 渭 m self-shape -semi-automorphism. The pyrite in the D vein of the seed crystal is cubic, the grain size is about 10~20mm, and the three groups of vertical grain develop mutually. The grain size of pyrite in the D vein is gradually larger, and the grain size of the seed crystal grain is more regular, and the grain size of the pyrite grain in the D vein is gradually larger, and the grain size of the pyrite in the D vein is more regular, and the grain size is more regular. The results indicate that the crystallization rate of pyrite gradually slows down from the early to late metallogenic period, and the forming environment tends to be stable. XRD results show that there are many groups of pyrite characteristic peaks in the spectrum lines of each sample. However, there were differences in the development of strong peaks. The strongest peak was 28.5 擄, and the corresponding peak positions of 37.1 擄B and D were 37.1 擄/ 33.1 擄and 33.1 擄/ 56.3 擄, respectively. The diffraction peak pattern shows that the crystal shape of the sample is mainly octahedral simplex, followed by pentagonal dodecahedron. The forming temperature should be greater than 300 擄B vein samples should be composed of pentagonal dodecahedron simplex, followed by cubic simplex composed of 100) crystal plane. The formation temperature should be between 200 鈩，

本文編號：1920652