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1、四川盆地西部栖霞组热液白云岩中的自生非碳酸盐矿物黄思静 李小宁 黄可可 兰叶芳 吕杰 王春梅(油气藏地质及开发工程国家重点实验室（成都理工大学） ，成都 610059）摘要 热液环境是碳酸盐重要的成岩环境之一，MVT 铅锌矿床和某些白云岩储层都与之有关。通过薄片观察、扫描电镜和能谱分析，在四川盆地西部中二叠统栖霞组白云岩地层中发现了一些自生非碳酸盐矿物和焦沥青，包括伊利石、萤石、氟磷灰石、石英、重晶石和黄铁矿等，它们赋存于具不同结构的白云石的晶间/晶内孔隙和溶解孔隙中，尤其是非平直晶面鞍形白云石的溶解孔隙中。赋存自生矿物的白云石主晶的包裹体均一化温度主要分布在 80180之间，最高可达 240
2、以上。白云石溶解空间中萤石、氟磷灰石（也包括方解石）等以 Ca 作为阳离子自生矿物的存在，反映热液白云石沉淀后温度降低造成的流体性质的改变和白云石的溶解，热液蚀变作用还造成了伊利石的形成和黏土矿物的强迫热演化，白云石晶间焦沥青的存在则代表了有机质因热蚀变而发生的强迫成熟和过成熟。川西栖霞组碳酸盐岩的热液蚀变作用发生在距今 259 Ma 左右（中二叠世末）的东吴运动期间，与峨眉山玄武岩有关的热事件伴生。该期间古热流达 6080 mW/m2，甚至更高，持续时间约 6 Ma，此时栖霞组白云岩地层的埋藏深度500 m，因而热液蚀变过程与地热增温无关。白云岩地层中各种自生矿物和非正常有机质热演化形成的焦
3、沥青的存在为川西栖霞组碳酸盐岩所经历的热液环境成岩作用提供了依据。关键词 四川盆地西部；栖霞组；热液蚀变；萤石；氟磷灰石；重晶石；有机质强迫成熟；黏土矿物的强迫热演化Authigenic noncarbonate minerals in hydrothermal dolomite of Middle Permian Qixia Formation in the west of Sichuan Basin, ChinaHUANG Si-jing, LI Xiao-ning, HUANG Ke-ke, LAN Ye-fang, L Jie, WANG Chun-meiState Key Labor
4、atory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu 610059, ChinaAbstract: The hydrothermal environment is an important diagenetic environment. MVT lead and zinc ore deposits and some dolomite reservoirs are related to hydrothermal environments. Based o
5、n thin section examination, scanning electron microscopy and the energy dispersion X-ray analysis, some authigenic noncarbonate minerals, including illite, fluorite, fluorapatite, quartz, barite and pyrite, and pyrobitumen are identified in the Middle Permian Qixia Formation on the west of Sichuan B
6、asin. These minerals occur in the intercrystalline/intragranular pores and dissolution pores in dolomites with different textures, especially in the dissolution pores of nonplanar-saddle dolomite. Fluid inclusion homogenization temperatures of host dolomites mainly range from 80 to 180, up to 240 or
7、 higher. The occurrence of authigenic minerals taking Ca2+ as the cation, such as fluorite, fluorapatite and also calcite in the dissolution space of dolomite, reveals that the fall of temperature after the hydrothermal dolomite precipitation causes the change of fluid nature and dissolution of dolo
8、mite. The hydrothermal alternation also leads to the formation of illite owing to forced thermal evolution of clay minerals. Pyrobitumen existing between dolomite crystals represents the forced maturation and over maturation of organic matter due to hydrothermal alternation. The hydrothermal alterna
9、tion of carbonate rocks from Qixia Formation in the west of Sichuan Basin occurred during Dongwu Movement about 259 Ma B.P. (the late stage of Middle Permian), associated with the thermal events related to the Emeishan basalt eruption with paleoheat flow up to or higher than 6080 mW/m2 and duration
10、time of about 6 Ma. The buried depth of the dolomite strata in Qixia Formation was less than 500 meters at that period, so the process of hydrothermal alteration had nothing to do with geothermal gradient function. Various authigenic minerals and pyrobitumen formed by abnormal thermal evolution of o
11、rganic matter in the dolomite strata provide evidences for the hydrothermal environment diagenesis experienced by carbonates from Qixia Formation in the west of Sichuan Basin.Key words: west of Sichuan Basin; Qixia Formation; hydrothermal alternation; fluorite; fluorapatite; barite; forced maturatio
12、n of organic matter; forced thermal evolution of clay minerals下刚果盆地 A 区块下白垩统 Albian 阶沉积层序与古地理演化于水 1 文华国 2 郝立华 1 郝立业 1 程涛 1 郑荣才 2（1.中海石油研究中心，北京 100049； 2.油气藏地质及开发工程国家重点实验室(成都理工大学)，成都 610059)摘要 通过对西非被动大陆边缘下刚果盆地中的 A 区块沉积相和层序地层分析，确定Albian 阶主要为一套具“间断-交叉”混积机理的碳酸盐岩混杂陆源砂、泥沉积，可划分出5 个三级层序，经历了从混积缓坡周缘混积台地破裂混积台地
13、深水混积陆棚深海盆地（深水扇）的沉积演化全过程，对应于威尔逊构造旋回中后裂谷拗陷阶段向大陆漂移的过渡阶段，其中发育主力储、产层的 SQ2-SQ3 层序为型周缘混积-破裂台地沉积层序，可进一步划分为 TST 和 HST 两个体系域。解析了混积碳酸盐岩层序地层与沉积充填响应特征，建立了研究区混积碳酸盐岩“滑脱-盐拱- 转换”多因素联控的沉积演化模式，提出SQ3 层序时期的盐拱构造顶部呈帚状分布和垂向偏转加积发育的破裂混积台缘浅滩为最有利的储集微相类型；以 TST 和 HST 体系域作为编图单元，编制了 SQ2 和 SQ3 层序各体系域的岩相古地理图并探讨了有利储集相带展布规律，认为 A 区块 Al
14、bian 阶 SQ2-HST、SQ3-TST 和 SQ3-HST 三个体系域中预测出的叠置台缘浅滩，应成为今后的勘探重点。关键词 沉积-层序；混积碳酸盐岩；浅滩；沉积演化模式；层序- 岩相古地理；Albian阶；下刚果盆地Sedimentary sequence and paleogeographic evolution of Albian Stage, Lower Cretaceous in Block A of Lower Congo BasinYU Shui1, WEN Hua-guo2, HAO Li-hua1, HAO Li-ye1,CHENG Tao1, ZHENG Rong-ca
15、i21.Petroleum Research Center of CNOOC, Beijing 100049, China；2.State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu 610059, ChinaAbstract: Lower Congo Basin is located on the passive continental margin of West Africa. This paper studies t
16、he sedimentary facies and sequence stratigraphy of Block A, ascertains that Albian is a set of carbonate rocks mixed with terrigenous sand and mud forming in a mixed mechanism of “intermittence-cross” diamictic process. Albian can be divided into five third-order sequences in the area. The whole sedimentary and evolutionary process of the strata has undergone the sedimentary rampperipheral diamictic platformfractured diamictic platformdeep-water diamictic con
