塔里木盆地柯坪地区中上寒武统白云岩沉积微相

在塔里木盆地西北缘柯坪地区的蓬莱坝剖面发现一套完整的寒武系白云岩地层,对其进行了系统的野外测量、岩性描述、样品采集和镜下观察,作出了完整的地层岩性沉积相综合柱状图,并对其进行沉积相、亚相和微相的分析.在该剖面中,识别出1种相——碳酸盐岩台地相,并进一步分为3种亚相和6种微相,分别为:开阔台地亚相(开阔潮坪、颗粒滩)、局...     

塔里木盆地塔中地区下奥陶统白云岩成因

塔里木盆地塔中地区下奥陶统白云岩广泛发育,岩石类型复杂多样,主要包括结晶白云岩、残余颗粒白云岩、残余灰质白云岩、藻云岩、亮边雾心白云岩、环带白云岩及少量膏云岩等结构类型。白云岩交代现象明显,δ18O普遍为中—高负值（-3.2‰～-8.7‰）;δ13C值基本为低中负值（-3‰～-0.77‰）,Z值大多集中在118～123...     

西沙中新世化石仙掌藻礁矿物岩石孔渗层特征及成因模式

Halimeda is one of the major reef-building algas in the middle Miocene of Xisha, and one of the significant reefbuilding algas in the algal reef oil and gas field of the South China Sea. However, there have been few reports regarding the characteristics of mineral rocks, reservoir porosity and permeability layers, and sedimentationdiagenetic-evolution of fossil Halimeda systems. The present paper briefly introduces the relevant studies on chlorophyta Halimeda and the research status of oil and gas exploration. Through the 1 043 m core of the Xichen-1 well, we studied the characteristics of the mineral rocks and porosity and permeability of the middle Miocene Halimeda of the Yongle Atoll, identified and described the segments of fossil Halimeda, and pointed out that most of the segment slides are vertical sections in ovular, irregular or long strips. The overwhelming majority of these fossil Halimeda found and studied are vertical sections instead of cross sections. In this paper, knowledge regarding the cross sections of fossil Halimeda is reported and proven to be similar with the microscopic characteristics of modern living Halimeda; fossil Halimeda are buried in superposition; it is shown that there are different structures present, including typical bio-segment structure, and due to its feature of coexisting with red alga, tying structure, twining structure and encrusting structure are all present; and finally, it is suggested to classify the fossil Halimeda into segment algal reef dolomites. In addition, all of the studied intervals are moderately dolomitized. Secondary microcrystalline-dolosparite dominates the original aragonite raphide zones,and aphanitic-micrite dolomite plays the leading role in the cortexes and medullas; in the aragonite raphide zones between medulla and cysts, secondary dissolved pores and intercrystalline pores are formed inside the segments, and algal frame holes are formed between segments; therefore, a pore space network system(dissolved pores + intragranular dissolved pores—intercrystalline pores + algal frame holes) is established. Segment Halimeda dolomite has a porosity of 16.2%–46.1%, a permeability of 0.203×10–3–2 641×10–3 μm2, and a throatradius of 23.42–90.43 μm, therefore it is shown to be a good oil and gas reservoir. For the reasons mentioned above, we suggest building the neogene organic reef-modern reef sedimentation-diagenetic-evolution models for the Xisha Islands.     

江汉盐湖盆地盐间白云岩特征及成因分析

江汉盐湖盆地潜江凹陷古近系潜江组广泛沉积了一套盐间非砂岩,本文详细研究了该套盐间非砂岩中白云岩的分布、类型、矿物学特征及地球化学特征,探讨了盐间白云岩的成因。研究表明,该套白云岩主要为泥晶白云岩。发育程度与盐岩量成正比。盐间白云岩的矿物组分复杂,白云石有序度低,微量元素以富Fe、Na、高Fe/Mn比值为特征。盐间白云岩主要为盐湖湖盆沉积环境的产物,水体盐度高,总体为碱性环境,Mg/Ca比值低,主要为原生-准同生阶段沉积的产物。     

塔里木盆地北部上震旦统葡萄状白云岩的发现及成因探讨*

“皮壳—葡萄状”白云岩是一种非常特殊结构的白云岩。文中报道了塔里木盆地西北缘东二沟及塔北星火101井上震旦统奇格布拉克组中皮壳—葡萄状白云岩特征,并对其成因进行了探讨。皮壳状—葡萄状白云石中发育明、暗纤状白云石或纹层条带的含少量细晶的纤状—细粒状白云石以及肾状和葡萄状粉细晶白云石;由球形、杆形、孢子形等蓝细菌构成泡沫状结构;明暗、环带状橙红色光或中等橙红色光、核部发光较暗或不发光;与基质白云石相比,葡萄—皮壳状白云石δ13CPDB相似;但δ18OPDB正偏, ⁸⁷Sr/⁸⁶Sr 相对高(0.70887~0.70939)、但与震旦纪海水(0.7087~0.7094)相似,从皮壳边缘、暗色(蓝细菌)至核部,微区δ18OPDB、δ13CPDB显示了环带内变化较小、环带外的强烈负漂移;云化程度的增加,δ18OPDB、δ13CPDB负偏明显, ⁸⁷Sr/⁸⁶Sr 增加。皮壳—葡萄状白云岩中Al₂O₃ 、Fe₂O₃ 、MnO、LREE/HREE值均低于基质泥粉晶云岩对应值、稀土总量介于基质与粉细晶云岩之间,而Na₂O+K₂O、P₂O₅、 Sr、Hg、Cu、Sr/Ba、Sr/Mn、δCe值均高于基质泥粉晶云岩对应值;且随着云化程度的提高,总体呈现出Mn含量增加,Al₂O₃ 、Fe₂O₃ 、Na₂O+K₂O、P₂O₅、Sr/Ba、Fe/Mn等值递减的趋势;由此判断皮壳状—葡萄状白云石可能是弱还原、保存较好的海水中形成,或在成岩早期或浅埋藏孔隙海水为主的流体中形成、部分经历了较强的大气水作用改造。     

塔东低凸起震旦系断陷台地沉积特征及发育模式

本文综合利用钻井岩心、地震剖面等资料,揭示了塔东低凸起震旦系沉积特征,并建立了沉积演化模式。研究认为,塔东低凸起震旦系白云岩可划分为三种沉积相类型,包括潮坪相、颗粒滩相和缓坡相。连井对比及地震剖面揭示,塔东低凸起震旦系具有楔状反射结构,反映了向北倾的断陷盆地沉积结构特征,整体上具有南高北低的沉积格局。本文结合区域构造背景,建立了由早期的向北缓倾单斜逐渐演变为断陷台地的沉积演化模式,认为断陷台地的主体发育在塔东1井至东探1井北部的斜坡部位。     

贵州梵净山西北陡山沱组底部白云岩帽地球化学特征及成因探讨

通过对贵州梵净山西北新元古代白云岩帽的研究,发现其δ13CPDB值与全球其他地区冰川混积岩(Marinoan冰期)之上的碳酸盐岩帽中δ13CPDB值一样,发生了一次明显的负偏移,从-1.4‰变化到-8.52‰,平均值为-4.52‰;δ18OPDB值从-5.44‰变化到-11.34‰,平均值为-8.68‰。除了白云岩帽顶部的两个数据之外,δ13CPDB值和δ18OPDB值均大体表现为随剖面向上升高的趋势,而且两者显示了弱的正相关性。沉积构造和碳同位素值说明,该套白云岩帽的形成与海底永冻土的固态甲烷释放无关,应为南沱冰期后,气候急剧变暖,大量风化的陆源碱性物质因海平面快速的上升被携带到海洋中,与CO2发生反应,快速沉淀下来的结果,支持了“雪球地球假说”。     

Recharge and salination processes in the carbonate aquifers in Israel

Limestone and dolostone aquifers play a major role in the water supply system of Israel. In many cases, there are brackish to saline springs at their outlets. The source of the saline water and the mechanism of salinization differ from place to place. In some cases, it is due to mixing with seawater (Mediterranean or Dead Sea) at the fresh-saline water interface, while in other cases deepseated brines emerge along regional faults. The general policy for reclaiming the fresh component of the water before mixing with the saline component is to try to catch the fresh water as far as possible upstream from the outlet. In most cases, this is the area where the mixing takes place. The main case histories in Israel are discussed in this paper.     

白云岩成因在层序地层研究中的应用——以龙门山泥盆系为例

在详细的露头层序地层学研究基础上，本文将龙门山泥盆纪白云岩划分为层序界面上的、低水位和高水位的３种产状类型、各类白云岩岩石学、矿物学和碳氧同位素特征各不相同，分别具蒸发泵、埋藏、混合水和大气水淋滤－－重结晶改造白云岩石化模式，发育条件均受海平面升降水和大气水淋滤－－重结晶改造白云岩石化模式，发育条件均受海平面升降变化控制，与沉积，成岩环境的演化密切相关。研究表明，各类白云岩的成因特征可作为识别层序