【作者】 田钊；

【导师】 柳成志；

【作者基本信息】 大庆石油学院 ， 矿产普查与勘探， 2009， 硕士

【摘要】 本文在大量岩石薄片鉴定的基础之上,利用岩石地球化学分析资料和前人研究成果等资料,完成了研究区营一段复杂岩性岩石的类型的详细分类总共划分出23种岩石类型。本区所取营城组火山岩化验分析样品绝大多数投在流纹岩的范围内,显示高硅的特点,以钙碱性岩为主,其次是钙性岩、碱性岩和强碱性岩;K2O含量与SiO2含量呈正相关趋势;Na2O与SiO2含量整体上呈负相关趋势;火山岩中微量元素含量均与SiO2含量呈负相关趋势。都有轻稀土元素富集的特征,流纹岩具有明显的Eu负异常、高场强元素Nb、Ta、Zr、Hf的低谷,这些特征表明火山岩是壳幔混合作用的结果。利用岩石地球化学分析资料为基础,结合岩心、测井资料,系统研究了本区火山岩的岩石地球化学特征并对其进行岩石系列划分。通过对本区各井岩相的研究,并参考了前人对本区的研究成果,对岩相进行了细致的分类将本区营城组火山岩划分为5个相16个亚相。据野外露头和岩心资料,综合利用地震、录井和测井信息建立火喷发旋回期次的标志。并对研究区火山岩的旋回及期次进行了详细划分,将划分四个喷发旋回,由下至上分别为旋回Ⅰ、旋回Ⅱ、旋回Ⅲ和旋回Ⅳ。从地质年代学,地球化学和岩石成因等方面看,松辽盆地及其周围白垩纪的火山岩属于相同的岩石组合。它们的地球化学特征和火山岩分布方式说明了它们是在一个活动的大陆边缘形成的,这个大陆边缘跟中生代蒙古-鄂霍斯克海向松辽盆地北部的闭合有关。更多还原

【Abstract】 Based on a great quantity of petrographic thin section analysis , geochemical analysis and previous research results, this essay deals with the close classification of complex lithological rocks and concludes that there are all together 23 forms of rocks. Most of the test samples taken from Yingcheng formation are rhyolite and show some distinguishing features such as high silicon.For example,the primary components are alkali calcic rocks, what take the second place are calcic rocks, alkali rocks and strong caustic rocks;The quantity of K2O is positive proportion to that of SiO2;quantity of Na2O is inverse proportion to that of SiO2;Accessory elements in volcanics are also inverse proportion to quantity of SiO2. Meanwhile, rare-earth elements are very rich in these smples. Rhyolites have obvious Eu negative anomaly and troughs of high field strength elements--Nb、Ta、Zr、Hf,All the above mentioned features prove that the formation of volcanics are the results of crust-mantle intermingling.By the use of geochemical analysis, combining with rock core and logging materials, author studies the volcanic rock geochemical behavior and makes a systematical classification. In reference to prevenient research findings and the study, this essay establishes typical lithofacies denotations. According to the lithologic characters, volcanics lithofacies of Yingcheng formation can be divided into 5 facies and 16 subfacies. On the basis of outcrop materials , rock core materials, seismic data, log data and log information ,author sets up signs for volcanic eruption cycle and subdivides it to 4 eruption cycle phases- CycleⅠ, CycleⅡ,CycleⅢ,CycleⅣ. From the view of Geochronology, geochemistry and lithogenesy, Songliao basin and the volcanics formed in Cretaceous Period around it belong to the same rock association.Geochemical behaviors and volcanics distribution classify that volcanics are formed at continental margin which is related with the closure of Mongolia-Okhotsk to northern Songliao basin at Mesozoic Era.更多还原