渤海湾盆地塘沽地区古近系沙河街组湖相白云岩特征及成因

王兵杰, 蔡明俊, 林春明, 张霞, 程远忠, 曲长伟, 张妮. (2014)渤海湾盆地塘沽地区古近系沙河街组湖相白云岩特征及成因[J]. 古地理学报, 16(1): 65-76
Wang Bingjie, Cai Mingjun, Lin Chunming, Zhang Xia, Cheng Yuanzhong, Qu Changwei, Zhang Ni. (2014)Characteristics and origin of lacustrine dolostone of the Paleogene Shahejie Formation in Tanggu area,Bohai Bay Basin[J]. Journal Of Palaeogeography, 16(1): 65-76. DOI:10.7605/gdlxb.2014.01.007 复制到剪切板

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王兵杰¹, 蔡明俊², 林春明¹, 张霞¹, 程远忠², 曲长伟¹, 张妮^1,³

1 内生金属矿床成矿机制研究国家重点实验室,南京大学地球科学与工程学院,江苏南京 210093

2 中国石油大港油田分公司,天津 300280

3 金陵科技学院,江苏南京 211169

通讯作者简介林春明,男,1964年生,南京大学教授、博士生导师,主要从事沉积学和石油地质学研究。E-mail:cmlin@nju.edu.cn。

第一作者简介王兵杰,女,1988年生,南京大学硕士研究生,主要从事沉积学与石油地质学研究。E-mail:dolomite88@126.com。

收稿日期:2013-04-19

基金:国家自然科学基金项目(编号:41272124)和南京大学“内生金属矿床成矿机制研究国家重点实验室”自主研究基金项目(编号:2009-Ⅱ-11)共同资助

摘要

渤海湾盆地塘沽地区古近系沙河街组三段沉积早期为半封闭的湖湾沉积环境,底部发育一套白云岩储集层,其产出受区域内北东向古潜山基底断裂控制,沿古潜山两侧发育,分布面积较大,累计厚度可达 100多米。系统的岩石学、矿物学和地球化学特征研究表明,该套白云岩常与泥岩互层产出,白云石主要为铁白云石和含铁白云石,普通显微镜下呈微晶状,扫描电镜下可见菱面体状晶型; X射线衍射分析表明其形成于准同生期,是快速结晶的产物;碳氧同位素分析及稀土元素分析显示,这类微晶白云岩形成于较为封闭的高盐度蒸发环境中,具统一的流体来源和相同成因机理。基于上述研究成果,认为塘沽地区沙河街组三段微晶白云岩的形成主要经历了准同生期回流渗透作用和成岩期埋藏环境下类质同象交代作用两个阶段。

关键词: 湖相白云岩; 微晶白云岩; 塘沽地区; 渤海湾盆地; 沙河街组

中图分类号:P588.24⁺5 文献标志码:A 文章编号:1671-1505(2014)01-0065-12

Characteristics and origin of lacustrine dolostone of the Paleogene Shahejie Formation in Tanggu area,Bohai Bay Basin

Wang Bingjie¹, Cai Mingjun², Lin Chunming¹, Zhang Xia¹, Cheng Yuanzhong², Qu Changwei¹, Zhang Ni^1,³

1 State Key Laboratory for Mineral Deposits Research,School of Earth Sciences and Engineering, Nanjing University,Nanjing 210093,Jiangsu

2 PetroChina Dagang Oilfield Company,Tianjin 300280

3 Jinling Institute of Technology,Nanjing 211169,Jiangsu

About the corresponding author Lin Chunming,born in 1964,is a professor of Nanjing University,and is mainly engaged in sedimentology and petroleum geology.E-mail: cmlin@nju.edu.cn.

About the first author Wang Bingjie,born in 1988,is a master candidate of Nanjing University. She is mainly engaged in sedimentology and petroleum geology.E-mail: dolomite88@126.com.

Abstract

The Member 3 of Paleogene Shahejie Formation,in the Tanggu area of Huanghua Depression,Bohai Bay Basin,was formed in semi-enclosed lake bay environment,with one set of dolostone reservoir developed at its bottom.The dolostone,with a cumulative thickness up to 100 meters,was mainly distributed along the sides of a buried hill as controlled by a NE trending basement fault.Generally,it was interbedded with mudstone in this area.Petrological,mineralogical and geochemical characteristics were studied,which shows:(1)The dolomite minerals are mainly ankerite and ferruginous dolomite,which are micrites under an optical microscope while rhombohedral crystals under a scanning electron microscope(SEM).(2)X-ray diffraction analysis indicates that this kind of micritic dolostone was formed during the penecontemporaneous period,and is the product of rapid crystallization.(3)The analytical result of the carbon and oxygen isotopes and the rare earth elements shows that it was formed in a relatively closed and high salinity evaporitic environment,and owns an unified fluid source and the same genetic mechanism.Based on the above analyses,the author holds the view that the micritic dolostone experienced two stages,namely the seepage-reflux dolomitization during penecontemporaneous period and the isomorphous replacement during burial diagenesis period.

Key words: lacustrine dolostone; micritic dolostone; Tanggu area; Bohai Bay Basin; Shahejie Formation

Show Figures

目前世界上近60%的油气都储存在碳酸盐岩中, 其中白云岩在碳酸盐岩储集层中占50%, 北美地区比例可达80%(Zenger et al., 1980), 因此, 白云岩是碳酸盐岩油气勘探的重要对象(顾家裕, 2000)。与海相白云岩相比, 湖相白云岩在地质历史中分布较少, 人们对其重视和研究的程度远不如海相白云岩。近年来, 中国在泌阳凹陷古近系(孙尚如, 2004)、新疆三塘湖盆地二叠系(李红等, 2007)、辽东湾盆地古近系(戴朝成等, 2008)、松辽盆地白垩系(王国栋等, 2008)和渤海湾盆地歧口凹陷古近系(廖静等, 2008)等地层中都发现了湖相白云岩。这些湖相白云岩形成环境及成因各不相同, 不同学者对其特征及形成机理进行了研究, 并相应提出了适合于其研究区的白云岩成因模式, 特别是对微生物成因白云岩(雷川等, 2012)及热水沉积成因白云岩(戴朝成等, 2008; 李红等, 2012)做了较多有意义的工作, 对中国湖相白云岩有了进一步的认识。文中通过岩心观察和描述、薄片和染色薄片鉴定、X射线衍射和电子探针分析、扫描电镜观察、碳氧同位素和稀土元素测试等手段, 对渤海湾盆地塘沽地区古近系沙河街组三段(文中简称“ 沙三段” )湖相白云岩的岩石学、矿物学和地球化学特征等进行了较为系统的研究, 并对其成因进行了初步探讨。

1 地质概况

塘沽地区位于渤海湾盆地黄骅坳陷西北部, 位于夹在北塘、歧口、板桥3大生油凹陷之间的中央隆起上, 其南侧为海河断层, 北侧为塘北断层, 为由这2个断层所夹持的1个地垒构造(图 1)。在海河断层上升盘, 存在1个奥陶系背斜圈闭, 轴向北东向, 为一个埋深浅、圈闭面积大的古潜山。

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	图1 渤海湾盆地塘沽地区位置Fig.1 Location of Tanggu area, Bohai Bay Basin

塘沽地区古生界主要为奥陶系灰岩, 中生界为一套红色砂泥岩互层, 新生界自下而上发育了古近系沙河街组和东营组、新近系明化镇组和馆陶组以及第四系平原组, 沙河街组可进一步分为3段, 自下而上分别为沙一段、沙二段和沙三段, 其中沙三段为本次研究的目的层段。按照地层旋回性及含油气性特征, 又可将沙三段自下而上划分为5个油层组, 分别为沙3⁵、沙3⁴、沙3³、沙3²和沙3¹油层组。本次研究的白云岩主要分布在沙3⁵油层组中, 该油层组下部发育深灰色泥岩与砂质泥岩, 上部为白云质泥岩和泥质白云岩。受背斜地貌影响, 沙3⁵油层组白云岩沿古潜山两侧分布, 最大沉积厚度可达100多米。

2 沉积特征

沙3⁵油层组白云岩常与泥岩呈韵律性互层, 其产状主要有灰白色白云岩与灰褐色泥岩不等厚互层(图 2-a)、灰白色白云岩夹薄层灰褐色泥岩(图 2-b)和灰白色白云岩与深灰色泥岩等厚薄互层(图 2-c)3种类型。薄片观察发现, 白云岩主要由微晶白云石构成(图 2-d), 有时微晶白云石与泥质组分互成纹层(图 2-e), 其中白云岩纹层厚0.1~0.3 mm, 泥质纹层厚0.05~0.1 mm。

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	图2 渤海湾盆地塘沽地区沙河街组三段岩性及矿物特征Fig.2 Photos showing lithologic and mineral characteristics of the Member 3 of Shahejie Formation in Tanggu area, Bohai Bay Basin

显微镜下白云石颗粒晶形不可辨, 扫描电镜下可见部分白云石呈半自形— 自形的菱面体状(图 2-f)。对较纯白云岩样品进行了电子探针微区化学成分分析, 共打点26个(表 1), 发现样品的主要化学成分为CaO和MgO, 其次为FeO, 其他均为微量成分。因电子探针对轻元素的数据采集不到, 故成分分析中总量不足100%的部分应是CO₂的含量。CaO、MgO及FeO形成白云石, 根据矿物学规定(王璞等, 1987), 当FeO含量大于MgO时, 为铁白云石, 而当FeO含量小于MgO时, 为含铁白云石, 故研究区白云石主要为铁白云石和含铁白云石, 铁白云石中FeO含量为12.564%~16.329%, 含铁白云石中FeO含量为6.205%~8.011%。用铁氰化钾和茜素红对薄片进行染色, 铁白云石及含铁白云石呈蓝色(图 3-a), 未染色部分为正常不含铁的白云石。

表1 渤海湾盆地塘沽地区沙河街组三段白云石电子探针分析结果 Table 1 EPMA analyses of dolomite samples from the Member 3 of Shahejie Formation in Tanggu area, Bohai Bay Basin

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	图3 渤海湾盆地塘沽地区沙河街组三段矿物组成及古生物特征Fig.3 Photos showing mineral characteristics and palaeotological features of the Member 3 of Shahejie Formation in Tanggu area, Bohai Bay Basin

薄片观察及X射线衍射分析表明, 白云岩中主要矿物组分除铁白云石、含铁白云石外, 还含有较多黏土矿物及方沸石(图 3-b), 其中黏土矿物主要为伊蒙混层和伊利石, 还含有少量绿泥石及高岭石, 方沸石多呈微晶粒状, 通常与泥质组分互成纹层(图 3-c), 也有少量为粉晶粒状, 且多充填在裂缝中, 粒间可含油(图 3-d), 推测这些方沸石为碱性环境中化学沉积或胶体转变而成的产物(周建民等, 1995); 次要矿物包括陆源碎屑、黄铁矿(图 3-e)、重晶石(图 3-f)、方解石、菱铁矿和锐钛矿等。黄铁矿在研究区内较为普遍, 其形成于同生期及准同生期, 为还原条件下有厌氧细菌作用、介质pH值达9以上的环境的产物(田景春等, 2000)。

此外, 在T39-3井的3831.72 m、3829.74 m及3828.56 m深度处还发现大量介形虫生物壳体(图 3-g, 3-h, 3-j), 多为单瓣壳, 破碎较严重。这种壳体的分离和破碎现象可由水动力条件所致, 即水动力强、冲刷严重, 则壳体容易分离和破碎, 此外, 压实作用、沉积速率及化学溶蚀因素等也可影响到壳体的保存状态(刘传联等, 1998), 因此, 难以单用介形虫壳体的破碎程度来准确推测其生存的环境条件。

研究区泥岩呈灰褐色或深灰色, 色调不及深湖相泥岩的颜色深, 表明其深湖环境的可能性较小, 而普遍发育的黄铁矿显示, 该环境具备相对还原的水体条件, 因此, 推测塘沽地区沙三段白云岩形成于水体流通不畅、缺氧的浅水湖湾环境中。湖湾的形成是由于研究区奥陶系古潜山的生长形成了水下隆起, 水下隆起的遮挡作用使湖泊近岸地区形成了半封闭的湖湾地带。

3 地球化学特征

3.1 X射线衍射分析

通过X射线衍射方法对白云岩中微晶白云石晶体结构的有序度进行了详细研究, 并确定了白云石晶格中CaCO₃的摩尔含量。有序度是通过白云石晶体的(015)和(110)两个衍射峰的面积比I₍₀₁₅₎/I₍₁₁₀₎近似地反映, CaCO₃摩尔含量( $\begin{matrix} N_{CaC O_{3}} \end{matrix}$ )通过白云石的最强衍射峰的面网间距值d₍₁₀₄₎来确定, 计算公式为 $\begin{matrix} N_{CaC O_{3}} \end{matrix}$ =333.33× d₍₁₀₄₎-911.11(钱光人, 1999)。研究区微晶白云石有序度变化范围为0.21~0.64, 平均值为0.40。通过公式求得白云石中CaCO₃摩尔含量为49.05%~56.95%, 平均为52.81%(表 2)。

表2 渤海湾盆地塘沽地区T12c井沙河街组三段微晶白云石有序度及CaCO₃摩尔含量 Table 2 Ordering degree and CaCO₃ mole content of micritic dolomites from the Member 3 of Shahejie Formation in Well T12c of Tanggu area, Bohai Bay Basin

将研究区白云石的有序度和CaCO₃摩尔含量与中国其他地区不同成因的湖相或海相白云岩中白云石进行对比(表 3), 发现海相白云岩中的白云石有序度普遍较高, 在0.60~1.10之间, 而湖相白云岩中的白云石有序度较低, 且变化范围大。研究区白云石有序度较低, 仅高于东营凹陷湖相微晶白云石和辽东湾盆地泥晶白云石, 而其CaCO₃摩尔含量除低于歧口凹陷泥晶白云石外, 均比其他盆地含量高, 这种低有序度和高CaCO₃摩尔含量的特征, 表明研究区白云石形成于成核结晶速度较快、相对不稳定的准同生成岩环境(何莹等, 2006)。这种环境下, 成岩流体的金属阳离子丰度较高, Mg²⁺置换Ca²⁺的速度较快, 在离子表面上来不及进行有规律的排列, 从而成为白云石矿物有序度较低的白云岩。

表3 渤海湾盆地塘沽地区与其他地区白云石有序度及CaCO₃摩尔含量对比 Table 3 Comparison of degree of order, CaCO₃ mole content of dolomites from Tanggu area of Bohai Bay Basin and other areas

3.2 碳氧同位素分析

白云岩的碳氧同位素组成可用来分析湖盆是开放性还是封闭性环境, 定量恢复沉积环境的古盐度和古温度以及研究白云岩的形成机理。通过对研究区16块微晶白云岩样品碳氧同位素的测定(表 4), 得出研究区碳氧同位素具有以下特征:

表4 渤海湾盆地塘沽地区沙河街组三段微晶白云岩碳氧同位素分析结果 Table 4 Analysis data of carbon and oxygen isotopes in micritic dolostone from the Member 3 of Shahejie Formation in Tanggu area, Bohai Bay Basin

样品号	深度 /m	$\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ /‰	$\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ /‰	古盐度指数Z	古盐度S /‰	古温度 /℃
T7	3100.48	3.2	-4.5	131.6	30.3	35.1
T19	3123.78	5.4	-5.4	135.7	29.4	39.5
T30	3133.03	3.5	-6.4	131.3	28.4	44.5
T40	3141.72	5.4	-6.6	134.0	28.2	45.6
T42	3143.47	5.4	-7.0	134.9	27.8	47.6
T44	3145.28	4.6	-4.7	134.4	30.1	36.1
T46	3146.45	6.0	-4.1	137.5	30.7	33.1
T48	3147.68	6.0	-5.2	137.0	29.6	38.5
T49	3147.78	5.0	-3.3	135.9	31.5	29.3
T50	3148.28	5.7	-5.3	136.3	29.5	39.0
T51	3148.76	4.9	-5.2	134.8	29.6	38.5
T52	3149.43	6.0	-4.4	137.4	30.4	34.6
T57	3155.36	8.2	-3.5	142.4	31.3	30.2
T58	3158.78	7.2	-6.3	138.9	28.5	44.0
T59	3160.39	8.7	-4.2	143.0	30.6	33.6
D3	3829.74	7.1	-6.0	138.9	28.8	42.5
平均值		5.8	-5.1	136.6	29.7	38.3

注:D代表T39-3井, T代表T12c井。

1)该区绝大部分白云岩的 δ ¹³C值分布在3.2‰ ~8.7‰ (PDB)之间, δ ¹⁸O值分布在-7.0‰ ~-3.3‰ (PDB)之间。一般情况下, 海水成岩环境中形成的白云岩 δ ¹³C为低正值或接近于零的负值, 而 δ ¹⁸O 值也接近于零(Veizer and Compston, 1974); 混合水成岩环境中形成的白云岩则具有较低的 δ ¹⁸O 和δ ¹³C值, δ ¹⁸O值通常在-9.0‰ ~-5.5‰ 之间变化, δ ¹³C值在-3.5‰ ~5.5‰ 之间变化(Badiozamani, 1973); 大气淡水贫δ ¹⁸O、富δ ¹³C, 因此, 大气淡水成岩环境中形成的白云岩 δ ¹⁸O、δ ¹³C值均向高负值滑移(叶德胜, 1993); 深埋藏环境中, δ ¹³C随埋深加大变化不大, 多为接近于零的正值, 而由于温度和压力增高 δ ¹⁸O 值会随埋深加大而减小, 分布范围较大, 反映了成岩作用的综合性和复杂性(金振奎和冯增昭, 1993; 顾家裕, 2000; 张霞等, 2009); 热液作用改造的白云石, 其 δ ¹⁸O 和δ ¹³C值更偏负, δ ¹³C值的变化范围比较大(-17.0‰ ~6.0‰ ), 但大部分在-3.0‰ ~5.0‰ 之间变化, δ ¹⁸O值通常在-18.0‰ ~-2.5‰ 之间变化, 多数分布在-10.0‰ ~-5.0‰ 之间, 相对比较负的 δ ¹⁸O 值与氧同位素热分馏有关(陈代钊, 2008)。

研究区白云岩δ ¹³C值相对上述模式有所偏高, 前人研究认为白云岩中δ ¹³C富集与生物埋藏速率较快(Schoelle and Arthur, 1980)和湖水盐度较高(张晓宝等, 2000)有关, 结合塘沽地区沙三段沉积环境, 推测该区这种δ ¹³C富集现象主要与湖水盐度较高有关。同时, 研究区白云岩相对较高的δ ¹³C和 δ ¹⁸O 值与准同生回流渗透白云岩特征(郑剑锋等, 2010)相似。

2)根据前人研究成果, 在开放型淡水湖泊中, 湖水停留时间短, δ ¹⁸O和δ ¹³C值之间无明显的相关性; 而在封闭型咸水湖环境中, 湖盆水体性质稳定, 湖相碳酸盐岩的 δ ¹⁸O 和δ ¹³C值之间呈明显的同步相关变化, 封闭性越强, 相关系数越大(Talbot, 1990; Li and Ku, 1997), 一般封闭性湖泊中的相关系数大于0.70(刘传联等, 2001)。现代湖泊中碳酸盐岩碳氧同位素研究发现, 开放型淡水湖泊的碳氧同位素投点多落在第三象限, 如瑞士Greifensee湖、美国Henderson湖和以色列Huleh湖(Talbot, 1990), 封闭性湖泊的碳氧同位素投点多落在第一、二象限, 如北美Great Salt Lake、非洲的Turkana、Natron-Magadi湖(Kelts, 1988)。研究区碳氧同位素的相关系数为0.71, 表明两者具相关性, 投点落在第二象限(图 4), 推测塘沽地区沙三段沉积时期湖盆水体具有一定封闭性, 但其相关性相对较弱, 反映了碳氧同位素的变化不是单一因素影响的结果。

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	图4 渤海湾盆地塘沽地区沙河街组三段白云岩及相关地区白云岩碳氧同位素散点图Fig.4 Scatter diagram of δ ¹³C and δ ¹⁸O of dolostone from the Member 3 of Shahejie Formation in Tanggu area of Bohai Bay Basin and other related areas

3)δ ¹⁸O和δ ¹³C值都与盐度有关, 其变化趋势都是盐度越高, δ 值越高(林春明等, 2002)。Keith和Weber(1964)提出利用Z值区分海陆相环境, 当Z值大于120时为海相; Z值小于120时为陆相。Z值计算公式为:

Z=2.048× ( $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ +50)+0.498× ( $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ +50)

利用Z值公式计算得出, 研究区Z值均大于120。利用盐度公式S=δ ¹⁸O_PDB+21.2/0.61计算得出, 研究区平均盐度为29.7‰ , 为咸水湖。这种高盐度的特征主要由两方面原因所致:一方面, 沙三段沉积时古气候较为炎热, 且湖盆水体较为封闭, 蒸发作用强烈, 导致湖水的输入量小于蒸发量; 另一方面, 推测研究区沙三段沉积时曾遭受过海水入侵的影响, 高盐度海水的入侵使湖泊水体含盐度增大, 研究区Sr/Ba值大于1(表5)也可说明这一点。

表5 渤海湾盆地塘沽地区T12c井沙河街组三段微晶白云岩微量元素Sr/Ba分析结果 Table 5 Analysis data of Sr/Ba in micritic dolostone from the Member 3 of Shahejie Formation in Well T12c of Tanggu area, Bohai Bay Basin

4)Keith和Weber(1964)提出, 利用氧同位素值还可以计算白云岩形成的环境温度, 其具体关系式为T=13.85-4.54× $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ +0.04× ( $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ )²。利用T值公式计算得出, 研究区白云岩平均成岩温度为38.3 ℃。白云石的人工合成实验及大量近代白云石沉积物的研究表明, 多数白云石形成于较高温度(28~35 ℃或更高)条件下(夏文杰, 1986)。这表明, 研究区白云岩成岩温度较高, 这可能与湖湾亚相下的蒸发环境有关。何莹等(2006)计算得到的塔里木盆地深埋热液白云岩形成温度平均为102 ℃, 与研究区白云岩形成温度具有明显的差异, 排除了研究区白云岩为热液成因的可能性。

3.3 稀土元素分析

湖相碳酸盐岩的稀土元素分布特征可以反映陆地古湖泊水体的水文地球化学状态和演变过程(伊海生等, 2008)。文中根据塘沽地区湖相白云岩REE的分布特点, 分析白云岩的成岩环境。

1)稀土元素总量。根据孙大鹏等(1994)对中国几大盐湖卤水及其沉积物中稀土元素含量的测定, 发现稀土元素总含量随盐湖卤水浓度增高而增大, 且盐湖卤水稀土含量高于一般海水, 其中轻稀土元素含量均高于重稀土。研究区8块白云岩样品的稀土元素总量(Σ REE)变化于(68.59~214.76)× 10^-6, 平均值为140.9× 10^-6, 远大于海水稀土总量(n× 10^-12~n× 10^-10)。推测这种稀土元素总量较高的特点与研究区卤水浓度高有关。

2)LREE、MREE、HREE特征。从LREE(La-Nd)、MREE(Sm-Dy)、HREE(Ho-Lu)的相对富集程度来看, 研究区白云岩样品的∑ LREE/∑ MREE变化于5.46~9.26之间, 而∑ MREE/∑ HREE在3.16~5.75之间变化(表 6), 具有明显的∑ LREE> ∑ MREE> ∑ HREE的特征, 为轻稀土相对富集、重稀土相对亏损的分布模式。其原因可能是由于随着原子数的增加, 稀土元素的稳定程度也增强, 轻稀土优先被有机质、黏土碎屑等吸附进沉积物中, 而重稀土则形成稳定络合物滞留在成岩流体中(朱丽霞等, 2010)。

表6 渤海湾盆地塘沽地区沙河街组三段白云岩稀土元素含量(W_B/10^-6) Table6 REE content of dolostone samples from the Member 3 of Shahejie Formation in Tanggu area, Bohai Bay Basin(W_B/10^-6)

3)Ce和Eu异常特征。Ce、Eu异常主要用来指示沉积环境的氧化还原性, Ce为正异常, 表明为氧化环境, 反之则为还原环境; Eu³⁺在还原条件下很容易还原成Eu²⁺, 后者常与Ca²⁺一起沉淀, 因此, 黏土矿物富集的湖相沉积岩中易出现Eu亏损, 而Eu正异常的湖相碳酸盐岩则被认为与湖底喷流热水有关(伊海生等, 2008)。研究区δ Ce的值在0.95~1.01之间, 未见明显富集或亏损, δ Eu的值在0.61~0.74之间, 呈中等— 弱的亏损状态, 与湖底喷流热水成因的湖相碳酸盐岩有较大区别, 推测其形成于相对低温的还原环境中, 此外, 可能和研究区黏土矿物含量高也有一定联系。

4)REE配分模式。经球粒陨石标准化后, 8块白云岩样品的分配曲线型式基本一致, 表现为一组缓右倾斜的相互平行的曲线, 曲线具有Eu负异常特征, MREE及HREE曲线相对较为平坦(图 5), 表明该白云岩具有较为一致的流体来源和相同的形成机理。

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	图5 渤海湾盆地塘沽地区沙河街组三段白云岩稀土元素配分特征Fig.5 REE distribution patterns of dolostone from the Member 3 of Shahejie Formation in Tanggu area, Bohai Bay Basin

4 白云岩成因

研究区白云岩的矿物成分主要为含铁白云石和铁白云石, 这些富含铁质的白云石, 一般形成于埋藏的还原成岩环境(谭荣等, 2001; 张枝焕等, 2003)。刘怀波等(1995)对美国俄克拉荷马州南哈桑气田的研究认为, 含铁白云石形成于100~120 ℃(埋深2800~3200 m), 铁白云石形成于120~130 ℃(埋深3200~3500 m), 而根据文中碳氧同位素计算所得结果, 研究区白云石平均成岩温度为38.3 ℃, 为近地表准同生成岩作用的产物。因此, 塘沽地区沙三段白云岩形成过程可能经历了2个阶段:第1阶段是在准同生期, 由“ 回流渗透成因” 生成了正常的不含铁的白云岩; 第2阶段是在埋藏还原环境下, 由地层水中的Fe²⁺对上述已经生成的正常白云岩中的Mg²⁺发生部分类质同象交代, 最终生成富含铁的白云岩。

4.1 回流渗透阶段

大量Mg²⁺的存在是形成白云石的先决条件, 研究区白云岩沉积时的高Mg²⁺主要是通过湖水蒸发作用形成的浓缩卤水获得, 海水入侵也可提供部分Mg²⁺。δ ¹³C和 δ ¹⁸O 值之间相关性的研究表明, 塘沽地区沙三段沉积时期处于半封闭环境, 当湖平面降低、气候相对干热时, 由于较强的蒸发使得空气— 液面界面所处的湖水盐度增高, 表层形成较重盐水, 重盐水中可分异出Mg²⁺, 这些Mg²⁺成为研究区富镁流体的重要来源。研究区白云岩Z值均大于120(表 5), 说明塘沽地区沙三段沉积时可能有海水阶段性地进入湖盆, 导致湖盆水体的盐度不断增高, 且前人对渤海湾盆地不同坳陷进行研究, 也分别发现了大量海侵证据(裘松余和卢兵力, 1994; 王冠民等, 2005; 袁文芳等, 2008)。海水中Mg²⁺浓度远高于湖水, 当其侵入湖水中时容易下沉, 使携带的Mg²⁺在湖中聚集。此外, 研究区奥陶系古潜山灰岩经历了加里东期和印支— 早燕山期的风化、剥蚀与淋滤, 溶蚀严重, 而新生代长期活动的海河断层直接沟通了古近系与奥陶系灰岩风化壳, 溶蚀的奥陶系灰岩既可提供碳酸钙流体, 成为白云化作用的先驱物, 又可提供部分Mg²⁺。

流体驱动力是白云岩形成的另一个关键因素。笔者认为研究区富Mg²⁺流体的驱动力主要有以下两种机制:一种是由于蒸发作用在湖水表层形成的重盐水在密度驱动作用下向湖底汇集; 另一种是富Mg²⁺流体在重力驱动作用下沿古隆起两侧斜坡流动, 即古隆起地貌在一定程度上控制了富镁流体的流向。

研究区沙三段微晶白云岩中白云石有序度低, 为准同生期产物, 且形成于低温封闭环境, 结合Mg²⁺来源及其流体驱动力, 推测该区湖相白云岩形成于浅水沉积环境, 为近地表回流渗透作用形成。总的来说, 研究区回流渗透白云岩的形成可归结为以下过程:由于湖水蒸发、海水入侵及奥陶系灰岩的溶蚀, 使湖水中Mg²⁺浓度大大增加, 这些富Mg²⁺的湖水在密度驱动和重力驱动作用下向湖底流动, 湖底水循环较差, 为还原环境, 形成高盐度碱性水介质条件, 当重盐水进一步渗入孔隙度较大的灰质沉积层时就会发生白云化作用, 由于该环境形成的白云岩成核结晶速度快, 便形成了有序度低、不含铁的微晶白云岩(图 6)。

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	图6 渤海湾盆地塘沽地区沙河街组三段回流渗透准同生白云化机理示意图Fig.6 Sketch of reflux penecon-temporaneous dolomitization mechanism of the Member 3 of Shahejie Formation in Tanggu area, Bohai Bay Basin

4.2 埋藏调整阶段

研究区不含铁的微晶白云岩, 随着埋深加大, 进入还原环境, 因为只有还原态的二价铁才有可能取代MgCO₃中的Mg²⁺(姚泾利等, 2009), 所以这种条件下白云岩中的白云石容易生成稳定相的铁白云石和含铁白云石。还原态的二价铁主要有2种可能来源:第一, 铁氧化物还原产生Fe²⁺; 第二, 混层黏土中, 蒙皂石向伊利石转化也会提供Fe²⁺(王婷婷, 2010)。这些Fe²⁺进入白云石晶格, 对上述准同生期回流渗透模式下生成的正常白云石中的Mg²⁺进行部分类质同象交代, 最终生成富含铁的白云石。

5 结论

1)渤海湾盆地塘沽地区古近系沙河街组白云岩主要为微晶白云岩, 白云石为铁白云石和含铁白云石。白云石有序度低, 为准同生条件下快速结晶的产物。碳氧同位素特征显示其形成的古温度较低, 湖盆环境较封闭, 古盐度指数Z值大于120, 推测有海水阶段性地进入湖盆。稀土元素特征显示该白云岩具有轻稀土富集、Eu负异常的特征, 表明白云岩形成于低温环境, 并且具有统一的流体来源和相同成因机制。

2)研究区白云岩形成主要经历了2个阶段:第1阶段是在准同生期, 由“ 回流渗透作用” 生成不含铁的白云岩, 其Mg²⁺主要来源于湖水蒸发作用形成的浓缩卤水及入侵海水, 富Mg²⁺流体的驱动力主要是盐度差异造成的密度驱动及古隆起引起的地貌斜坡的重力驱动。第2阶段是在深埋藏还原环境下, 由地层水中的Fe²⁺对上述已经生成的正常白云石中的Mg²⁺发生部分类质同象交代, 最终生成富含铁的白云石。

致谢论文得到了大港油田有关人员协助和支持, 陈顺勇、周健等参加部分研究工作, 并得到黄志诚、蔡元峰、赖明远、李娟等的帮助, 在此一并表示感谢!

参考文献

View Option

1	陈代钊. 2008. 构造—热液白云岩化作用与白云岩储集层[J]. 石油与天然气地质, 29(5): 614-622. [文内引用:1]
2	戴朝成, 郑荣才, 文国华, 等. 2008. 辽东湾盆地沙河街组湖相白云岩成因研究[J]. 成都理工大学学报(自然科学版), 35(2): 187-193. [文内引用:2]
3	顾家裕. 2000. 塔里木盆地下奥陶统白云岩特征及成因[J]. 新疆石油地质, 21(2): 120-122. [文内引用:2]
4	何莹, 鲍志东, 沈安江, 等. 2006. 塔里木盆地牙哈—英买力地区寒武系—下奥陶统白云岩形成机理[J]. 沉积学报, 24(6): 806-818. [文内引用:1]
5	金振奎, 冯增昭. 1993. 华北地台东部下古生界白云岩的类型及储集性[J]. 沉积学报, 11(2): 11-17. [文内引用:1]
6	雷川, 李红, 杨锐, 等. 2012. 新疆乌鲁木齐地区中二叠统芦草沟组湖相微生物成因白云石特征[J]. 古地理学报, 14(6): 767-775. [文内引用:1]
7	李得立, 谭先锋, 夏敏全, 等. 2010. 东营凹陷沙四段湖相白云岩沉积特征及成因[J]. 断块油气田, 17(4): 418-422. [文内引用:1]
8	李红, 柳益群, 梁浩, 等. 2012. 三塘湖盆地二叠系陆相热水沉积方沸石岩特征及成因分析[J]. 沉积学报, 30(2): 205-218. [文内引用:1]
9	李红, 柳益群, 朱玉双. 2007. 新疆三塘湖盆地二叠系湖相白云岩形成机理初探[J]. 沉积学报, 25(1): 75-81. [文内引用:1]
10	廖静, 董兆熊, 翟桂云, 等. 2008. 渤海湾盆地歧口凹陷沙河街组一段下亚段湖相白云岩及其与海相白云岩的差异[J]. 海相油气地质, 13(1): 18-24. [文内引用:1]
11	林春明, 凌洪飞, 王淑君, 等. 2002. 苏皖地区石炭纪海相碳酸盐岩碳、氧同位素演化规律[J]. 地球化学, 31(5): 415-423. [文内引用:1]
12	刘传联, 洪太元, 毕海红, 等. 1998. 东营凹陷沙河街组介形虫化石保存特征研究及应用[J]. 微体古生物学报, 15(2): 186-195. [文内引用:1]
13	刘传联, 赵泉鸿, 汪品先. 2001. 湖相碳酸盐氧碳同位素的相关性与生油古湖泊类型[J]. 地球化学, 30(4): 363-367. [文内引用:1]
14	刘怀波, 吴智勇, Blatt H, 等. 1995. 俄克拉荷马州南哈桑气田斯普罗砂岩的成岩作用和孔隙演化[J]. 江汉石油学院学报, 17(2): 1-9. [文内引用:1]
15	钱光人. 1999. 岩石的结构特征与碱碳酸盐反应[D]. 江苏南京: 南京化工大学. [文内引用:1]
16	裘松余, 卢兵力. 1994. 我国东部晚白垩世和早第三纪海侵与油气关系[J]. 地质论评, 40(3): 229-236. [文内引用:1]
17	史勇, 王超勇, 汪泽成. 2011. 鄂尔多斯南缘奥陶系下统马家沟白云岩成因分析[J]. 科技信息, 28: 25-27. [文内引用:1]
18	孙大鹏, 马育华, 李岫霞, 等. 1994. 我国盐湖卤水及其沉积物中稀土元素的初步研究[J]. 科学通报, 39(23): 2206-2207. [文内引用:1]
19	孙尚如. 2004. 泌阳凹陷湖相白云岩层序地层学分析[J]. 西北地质, 37(1): 30-35. [文内引用:1]
20	谭荣, 黄思静, 赵霞飞. 2001. 冷家沙三段砂岩成岩序列与孔隙演化[J]. 沉积与特提斯地质, 21(1): 44-49. [文内引用:1]
21	田景春, 曾允孚, 郑和荣, 等. 2000. 陆相含油盆地泥岩中白云岩夹层的储集性研究: 以东营凹陷沙三段上部白云岩为例[J]. 成都理工学院学报, 27(1): 88-92. [文内引用:1]
22	王冠民, 钟建华, 姜在兴, 等. 2005. 从济阳坳陷沙一段古盐度的横向变化看古近纪的海侵方向[J]. 世界地质, 24(3): 243-247. [文内引用:1]
23	王国栋, 程日辉, 王璞君, 等. 2008. 松辽盆地嫩江组白云岩形成机理[J]. 地质学报, 82(1): 48-54. [文内引用:1]
24	王璞, 潘兆橹, 翁玲宝. 1987. 系统矿物学[M]. 北京: 地质出版社, 1-734. [文内引用:1]
25	王婷婷. 2010. 宜昌陡山沱组第三岩性段条带状碳酸盐岩环境磁学研究[D]. 北京: 中国地质大学(北京). [文内引用:1]
26	夏文杰. 1986. 青海小柴旦盐湖滩岩中原生白云石的发现及其意义[J]. 沉积学报, 14(2): 19-25. [文内引用:1]
27	姚泾利, 王宝全, 王一刚, 等. 2009. 鄂尔多斯盆地下奥陶统马家沟组五段白云岩的地球化学特征[J]. 沉积学报, 27(3): 381-389. [文内引用:1]
28	叶德胜. 1993. 塔里木盆地北部震旦系至奥陶系白云岩的岩石学及地球化学特征[J]. 地球化学, 22(1): 1-9. [文内引用:1]
29	伊海生, 林金辉, 赵西西, 等. 2008. 西藏高原沱沱河盆地渐新世—中新世湖相碳酸盐岩稀土元素地球化学特征与正铕异常成因初探[J]. 沉积学报, 26(1): 1-10. [文内引用:2]
30	袁文芳, 曾昌民, 陈世悦. 2008. 济阳坳陷古近纪咸化层段甲藻甾烷和C₃₁甾烷特征[J]. 沉积学报, 26(4): 683-687. [文内引用:1]
31	张霞, 林春明, 凌洪飞, 等. 2009. 浙西地区奥陶系砚瓦山组瘤状灰岩成因探讨[J]. 古地理学报, 11(5): 481-490. [文内引用:1]
32	张晓宝, 王志勇, 徐永昌. 2000. 特殊碳同位素组成白云岩的发现及其意义[J]. 沉积学报, 18(3): 449-452. [文内引用:1]
33	张枝焕, 王泽中, 李艳霞, 等. 2003. 黄骅坳陷三马地区中—深部储集层成岩作用及主控因素分析[J]. 沉积学报, 21(4): 593-600. [文内引用:1]
34	郑剑锋, 沈安江, 莫妮亚, 等. 2010. 塔里木盆地寒武系—下奥陶统白云岩成因及识别特征[J]. 海相油气地质, 15(1): 6-14. [文内引用:1]
35	周建民, 杨清堂, 马秀莲, 等. 1995. 河南安棚碱矿中自生沸石的产状及成因探讨[J]. 化工矿产地质, 17(2): 111-115. [文内引用:1]
36	朱丽霞, 付修根, 谭富文, 等. 2010. 羌塘盆地那底岗日地区上侏罗统—下白垩统碳酸盐岩稀土元素地球化学与古气候[J]. 沉积与特提斯地质, 30(4): 92-96. [文内引用:1]
37	Badiozamani K. 1973. The Dorag dolomitization Model: Application to the Middle Ordovician of Wisconsin[J]. Journal of Sedimentary Petrology, 43(4): 965-984. [文内引用:1]
38	Keith M L, Weber J N. 1964. Carbon and oxygen isotopic composition of selected limestones and fossils[J]. Geochimica et Cosmochimica Acta, 28(10-11): 1787-1816. [文内引用:1]
39	Kelts. 1988. Environments of deposition of lacustrine petroleum source rocks: An introduction[J]. Geological Society, 40(1): 3-26. [文内引用:1]
40	Li H C, Ku T L. 1997. δ¹³C-δ¹⁸O covariabce as a paleohydrological indicator for closed-basin lakes[J]. Palaeogeography, Palaeoclimatology, Palaeoecology, 133(1-2): 69-80. [文内引用:1]
41	Schoelle R A, Arthur M A. 1980. Carbon isotope flutuations in Cretaceous pelagic limestones: Potential stratigraphic and petroleum exploration tool[J]. AAPG Bulletin, 64(1): 67-87. [文内引用:1]
42	Talbot M R. 1990. A review of the palaeohydrological interpretation of carbon and oxygen isotopic ratios in primary lacustrine carbonates[J]. Chemical Geology: Isotope Geoscience Section, 80(4): 261-279. [文内引用:2]
43	Veizer J, Compston W. 1974. ⁸⁷Sr/⁸⁶Sr composition of seawater during the Phanerozoic[J]. Geochimica et Cosmochimica Acta, 38: 1461-1484. [文内引用:1]
44	Zenger D H, Dunham J B, Ethington R L. 1980. Concepts and Models of Dolomitization[M]. Society of Economic Paleontologists and Mineralogists, Special Publication, 1-320. [文内引用:1]

2008

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陈代钊. 2008. 构造—热液白云岩化作用与白云岩储集层[J]. 石油与天然气地质, 29(5): 614-622.

Sharing similar lithologic characteristics with dolomite seam hosting MVT Pb-Zn sulfide ores,hydrothermal dolomite reservoirs contains mainly massive-matrix-replacement dolomites and void-or fracture-filling saddle dolomite dotted with small amount of other hydrothermal ores,such as sphalerite,galena,quartz,pyrite, barite,and fluorite.Saddle dolomite-filling microfractures and zebra textures formed by shear stress and dolomite breccias are also common in these reservoirs.Unfilled vugs,fractures,and pores from differential dissolution of the original carbonates(mainly limestone)provide the necessary spaces for later hydrocarbon charges.The hydrothermal fluids preferentially flow upwards along the extensional and transtensional fault systems,where dolomitization preferentially occurs on the hanging walls and extends laterally in the course of fault propagation.The hydrothermal dolomite reservoir can be well characterized and predicted through high-resolution seismic attribute analysis and imaging.

Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China

热液白云岩储层的岩石特征与密西西比 Pb-Zn 硫化矿床的白云岩容矿层相似,以广泛发育的基质交代型和孔-缝充填的鞍形白云石为标型特征,同时含有少量其他热液矿物如闪锌矿、方铅矿、石英、黄铁矿、重晶石以及萤石等,另外还经常可见被鞍形白云石充填的因剪切应力形成的微裂缝、斑马纹构造和白云岩角砾。由于热液流体对原碳酸盐岩(主要是灰岩)的差异性溶蚀,往往保留了未被充满的孔洞、缝,为油气的充注提供了空间。输导热液流体的断裂系统通常为张性或扭张性断裂系统,白云岩化作用主要发生在断裂系统的上盘,并沿着孔渗性相对较好的原岩侧向推进。借助于高分辨率地震属性分析和成像技术,可以对热液白云岩储层进行表征和预测,从而为油气勘探决策提供依据。

... ¹⁸O 值与氧同位素热分馏有关(陈代钊,2008) ...

2008

0.0

戴朝成, 郑荣才, 文国华, 等. 2008. 辽东湾盆地沙河街组湖相白云岩成因研究[J]. 成都理工大学学报(自然科学版), 35(2): 187-193.

辽东湾盆地古近系沙河街组产有一套分布仅限于深凹陷内的深湖相白云岩,岩性主要为泥-微晶白云岩,物质组分以铁白云石为主,在深湖相暗色泥岩中呈很薄的夹层产出,累计厚度6～10 m,产出位置明显受区域内辽中凹陷西界的北北东向基底断裂控制.通过系统的沉积学、岩石学、矿物学和地球化学特征研究,以及与酒西盆地青西坳陷下沟组热水白云岩成因特征对比,认为发育于旅大地区深凹陷内的沙河街组深湖相白云岩也属于罕见的湖相热水沉积岩.

... 近年来,中国在泌阳凹陷古近系(孙尚如,2004)、新疆三塘湖盆地二叠系(李红等,2007)、辽东湾盆地古近系(戴朝成等,2008)、松辽盆地白垩系(王国栋等,2008)和渤海湾盆地歧口凹陷古近系(廖静等,2008)等地层中都发现了湖相白云岩 ...

... 这些湖相白云岩形成环境及成因各不相同,不同学者对其特征及形成机理进行了研究,并相应提出了适合于其研究区的白云岩成因模式,特别是对微生物成因白云岩(雷川等,2012)及热水沉积成因白云岩(戴朝成等,2008 ...

2000

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顾家裕. 2000. 塔里木盆地下奥陶统白云岩特征及成因[J]. 新疆石油地质, 21(2): 120-122.

在整个地质历史中,有两个白云岩分布的高峰期,即中生界和下古生界.塔里木盆地寒武-奥陶系白云岩按其结构可分为七种类型,而且它们的碳氧同位素值也有较大的差异,微量元素的含量高低悬殊,包体均一温度差值幅度大,充分反映其成因的差异.按其岩性特征、碳氧同位素值、微量元素的含量和成岩温度可分为准同生白云岩、浅埋藏白云岩和深埋藏白云岩三类.

... , 1980),因此,白云岩是碳酸盐岩油气勘探的重要对象(顾家裕,2000) ...

... 顾家裕,2000 ...

2006

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何莹, 鲍志东, 沈安江, 等. 2006. 塔里木盆地牙哈—英买力地区寒武系—下奥陶统白云岩形成机理[J]. 沉积学报, 24(6): 806-818.

Research Institute of Exploration and Development,Southwest Branch,Sinopec,Chengdou 610081

根据铸体薄片鉴定、阴极发光显微镜观察、碳、氧稳定同位素测定、微量元素分析及包裹体测温等手段,对塔里木盆地牙哈—英买力地区寒武—下奥陶统深埋热液白云岩类型及成因机理进行了详细的研究。认为研究区深埋藏白云岩主要由细晶或中晶白云石组成,白云石呈自形或半自形晶。δ13CPDB值为-1.63‰~2.31‰,平均为0.25‰,δ18OPDB值为-11.49‰~-6.02‰,平均为-8.72‰;锶含量较低,在77×10-6~107×10-6之间,二价铁、锰含量较高,具有高的有序度和低的CaCO3摩尔含量的特点。各种资料表明,该类白云岩是在深埋藏环境中较高温度条件下形成的,白云岩的形成与海西期岩浆喷发活动有关,变质岩体的分布控制了白云岩的分布。白云化流体来自岩浆热液、变质热液、有机酸及区域地下热卤水的混合,白云化所需的Mg2+来自岩浆岩中铁镁矿物的分解、埋藏压实过程中粘土矿物的脱水作用等。因此其白云化机制可称之为“深埋热液白云化”。

... 研究区白云石有序度较低,仅高于东营凹陷湖相微晶白云石和辽东湾盆地泥晶白云石,而其CaCO₃摩尔含量除低于歧口凹陷泥晶白云石外,均比其他盆地含量高,这种低有序度和高CaCO₃摩尔含量的特征,表明研究区白云石形成于成核结晶速度较快、相对不稳定的准同生成岩环境(何莹等,2006) ...

1993

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金振奎, 冯增昭. 1993. 华北地台东部下古生界白云岩的类型及储集性[J]. 沉积学报, 11(2): 11-17.

Dolostones are very common in the Lower Paleozoic of eastern North-China Platform, and can be divided into mud-silt-sized crystalline dolostones and fine-coarse crystalline dolostones. The former includes gypsiferous and non-gypsiferous; the later includes equal-crystal and unequal-crystal fine-coarse crystalline dolostones. Gypsiferous mud-silt-sized crystalline dolostones are well laminated,show bird's-eyes and mudcracks,contain gypsum crystals or nodules,and are associated with chicken-wire or laminated gypsum rocks. Based on the analysis of two samples,their δ 13 C is 0. 42‰-2. 21‰, average 1. 13‰(PDB) ;δ18O is -6. 01‰-4. 77‰, average -5. 39‰(PDB). The low δ 18 O results from recrystallization in fresh water and/or under high temperatures. These dolostones are similar to the Sabkha penecontemporaneous dolostones in the Persian Gulf,and are formed in supratidal flats by evaporative pumping dolomitizatiom under arid climate. Non-gypsiferous mud-silt -sized crystalline dolostones are similar to the gypsiferous ones in texture and structure, but do not contain gypsum and are not associated with gypsum rocks. Based on the analysis of 17 samples,their δ 13 C is -3. 69‰-3. 41‰,average 0. 03‰;δ 18 O - 8. 17‰-4. 04‰,average -5. 91‰. The low δ 18 O also results from recrystallization in fresh water and/or under high temperatures. These dolostones are similar to the supralittoral penecontemporaneous dolostones on the Bahamian Platform, and are formed in supratidal flats by evaporative pumping dolomitization under humid climate. Equal-crystal fine to coarse crystalline dolostones are composed of dolomites of basically the same size. Euhedral and semi-euhedral dolomites are common,especially when dolomitization is incomplete. Some dolomites show dirty centers and clean marging,and may contaim calcite inclusions. Thses dolomites are formed directly by replacing limestones. Based on analysis of 15 samples,the δ 13 C is -2. 11‰-2. 10‰,average -0. 40‰;δ18O -8. 49‰-4. 09‰,average -5. 53‰. These dolostones are mostly distributed under the disconformity between the Lower and Middle Ordovician,and are formed by dorag dolomitization. Unequal-crystal fine-coarse crystalline dolostones are composed of dolomites of greatly different size. The dolomites are commonly anhedral. Based on analysis of 5 samples,the 513C is -4. 72‰～-1.08‰,average -2. 83‰;δ18O - 9. 27‰～- 7. 32‰, average -8. 31‰. These dolostones are formed by recrystallization of earlier dolostones in fresh water. Porosities of dolostones in the Lower Paleozoic can be divided into intracrystal pores,in-tercrystal pores,vugs,cast pores,fissures,bird's-eye pores and shrinking fissures. The reser-voiring performance of the dolostones are controlled by many factors,such as the content and size of dolomites,and clay content of the dolostones, non-clayey silt-sized crystalline dolostones show the best reservoiring performance.

University of Petroleum,Beijing

华北地台东部下古生界的白云岩可分为泥—粉晶白云岩和细—粗晶白云岩。前者包括含石膏的和不含石膏的;后者包括等晶粒的和不等晶粒的,含石膏的和不含石膏的泥—粉晶白云岩分别是干旱和潮湿气候潮上带蒸气发泵浓缩白云化的产物;等晶粒细—粗晶白云岩主要分布于平行不整合面之下,乃混合水白云化之产物;不等晶粒细—粗晶白云岩由早期的白云岩重结晶形成。白云岩中的孔隙类型多样,其储集性受白云石含量和颗粒大小以及粘土含量等因素影响。

... ¹⁸O 值会随埋深加大而减小,分布范围较大,反映了成岩作用的综合性和复杂性(金振奎和冯增昭,1993 ...

2012

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雷川, 李红, 杨锐, 等. 2012. 新疆乌鲁木齐地区中二叠统芦草沟组湖相微生物成因白云石特征[J]. 古地理学报, 14(6): 767-775.

The dark-gray，middle to thin-bedded dolostone，limestone，siltstone，and gray or black shale and mudstone，deposited in shallow to open lake settings, are mainly developed in the Middle Permian Lucaogou Formation in southern Hongyanchi section of rümqi in Xinjiang. Dolostone which is rich in organic matter is mainly composed of dolomite and ankerite with small amount of calcite and Mg-calcite.The dolomite ranges from 3 to 10μm in crystal sizes and shows homogeneously dark-red luminescence.Micromorphologies of the dolomite vary from microspherules(5～8μm in diameter)，clusters(about 2μm long)，to anhedral dolomite under the SEM.Microspherules have microlaminae structure called “growth coating” which consists of numerous nanoscale particles in the 60000 times enlarged SEM photomicrographs.Anhedral dolomite which is mainly composed of massive particles(about 0.25μm)in 40000 times enlarged SEM photomicrographs shows the features of microbial mineralization.The above morphologies of dolomite are highly similar to the typical modern microbial dolomite in experiment-culture and natural environments.The δ 13 C PDB value of dolomite ranges from 1.8‰ to 13.8‰，and δ 18 O PDB value ranges from-12.1‰ to-4.1‰.The higher δ 13 C PDB value may be the result of isotope fractionation led by methane-producing bacteria.The characteristics of micromorphologies and stable isotope indicate that the precipitation of the Middle Permian dolomite had close relation to activities of anaerobic organisms.

1 State Key Laboratory of Continental Dynamics，Department of Geology，Northwest University，Xi′an 710069，Shaanxi;2 Lanzhou Center for Oil and Gas Resources, Institute of Geology and Geophysics,Chinese Academy of Sciences，Lanzhou 730000,Gansu;3 Shaanxi Institute of Geological Survey，Xianyang 712000，Shaanxi

新疆乌鲁木齐地区红雁池南剖面中二叠统芦草沟组主要发育浅湖至半深湖背景下的中、薄层深灰色白云岩、灰岩、粉砂岩与中、厚层灰黑色页岩、泥岩互层。白云岩主要由泥晶白云石、铁白云石及少量方解石、高镁方解石组成，富含有机质。白云石粒径约3～10 μm，阴极发光呈现均匀昏暗的砖红色。白云石主要有微球状（直径约5～8 μm）、微簇状（长度约2 μm）及他形（1～10 μm）等3种微形貌。微球状白云石具有显微纹层结构，似为生长纹层，放大至6万倍发现显微纹层是由无数纳米级颗粒构成。他形白云石放大至4万倍发现主要由大量直径约0.25 μm的球状微粒聚集粘结而成，具有微生物矿化的特征。将研究区白云石与现代典型微生物成因白云石相比，其显微形态特征非常相似。研究区白云岩 δ 13 C PDB 为1.8‰～13.8‰， δ 18 O PDB 为-12.1‰～-4.1‰，偏高的 δ 13 C可能是产甲烷菌活动引起有机质碳同位素分馏的结果。以上特征表明，芦草沟组具有特殊形貌白云石的沉淀很可能与厌氧微生物密切相关。

2010

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2012

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李红, 柳益群, 梁浩, 等. 2012. 三塘湖盆地二叠系陆相热水沉积方沸石岩特征及成因分析[J]. 沉积学报, 30(2): 205-218.

Santanhu Basin, located in northeast of Xinjiang, China, was developed a contenental rift basin from Late Carboniferous to Middle Permian. On the outcrop and the drilling cores of the basin, layers of sublacustrine hydrothermal deposits from which six of them were sampled, were found in the thick mudstones in Lucaogou Formation(P2l), Middle Permian. The hydrothermal samples can be divided into two types: the first type is formed of analcime, sanidine, orthoclase, dolomite and ankerite.The carbonates were detected of concentrating iron and manganese. The second type is formed of analcime, quartz, and carbonates. Most analcime was observed to be xenomorphic block or amorphous gelatinoid otherwise from automorphic tetragonaltrisoctahedron under the SEM. Major elements of all samples were characterized as being rich in SiO2, Al2O3，Na2O，and poor in TiO2. Trace element of the samples show enrichemnt of highly incompatibility elements, such as Ba, Rb, K, Ta, Sr, Zr and Hf, and are lack of Th, Nb, and Ti relatively. The ratios of Sr/Nd = 44.73~831.78, Nb*=0.02~0.17. ΣREE= 7.33 ~20.619 μg/g, LaN/YbN=2.50 ~16.00, LREE/HREE=4.77～11.20. δEu varies from0.6 to 0.99 which shows negative anomalism to primitive mantle , however, δCe value which varies from 0.96 to 1.04 shows the similarity to primitive mantle. The major and trace elements (includes REE) reveal the distinct differences with the basalts and trachytoids of Permian in the same basin, and also disagree with the average value of Upper Crust. 87Sr/86Sr = 0.705 118~0.706 438, 143Nd/144Nd =0.512454~0.512713，εNd=0.81～3.84. Isotope composition indicates that mantle materials may participate in the hydrothermal fluid with which the hydrothermal minerals were deposited. By the analysis of the lithology, geochemistry, and Sr, Nd isotope, the characteristics of the samples suggest that they are an assemblage of hydrothermal rocks which are related to the hot springs exhalation at the lake bottom in Santanghu continental rift basin. Besides the Crust and meteoric components, the hydrothermal fluid of the rocks was probabely composed of the substance sourced from deep earth. 

在新疆三塘湖盆地野外露头及钻井中二叠统芦草沟组(P2l)厚层黑色泥岩中发现多层白色纹层状方沸石岩。根据主要造岩矿物特征，将其大致分为两类，第一类为方沸钾长白云岩，主要造岩矿物包括细粒方沸石、泥晶钾长石（透长石、正长石）、泥晶白云石、泥晶铁白云石等，碳酸盐矿物以高的Fe、Mn含量为特征；第二类为方沸硅质岩与硅质方沸石岩，以细粒方沸石及泥晶石英为主，含少量碳酸盐。扫描电镜观察方沸石以自形的四角三八面体少见，多为它形块状或无定形胶体状。样品主量元素以富SiO2、Al2O3、Na2O、贫TiO2为特征，微量元素Th、Nb、Ti强烈亏损，Sr/Nd比值为44.73~831.78，Nb*介于0.02~0.17之间。∑REE总量偏低7.33~20.619 μg/g，LREE/HREE为4.77~11.20，δEu 0.60~0.99略具负异常，δCe 0.96~1.04，基本无亏损，稀土配分曲线为较平缓的右倾。方沸石岩微量元素、稀土元素配分曲线与研究区早、中二叠世玄武岩、粗面岩及上地壳有较大差异。87Sr/86Sr介于0.705 118~0.706 438之间，低于同时期全球海水及中上二叠统海相碳酸盐的87Sr/86Sr比值，143PNd/144Nd介于0.512 454~0.512 713之间，εNd介于-0.81~3.84之间，表明造岩热液可能含有幔源组分。通过详细的岩石学、地球化学及Sr、Nd同位素研究，认为这是一类与陆相裂谷盆地湖底热泉喷流作用有关的热水沉积岩组合，热液组分除了有壳源物质及大气水等的混入外，可能还有深部物质的参与。

... 李红等,2012)做了较多有意义的工作,对中国湖相白云岩有了进一步的认识 ...

2007

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李红, 柳益群, 朱玉双. 2007. 新疆三塘湖盆地二叠系湖相白云岩形成机理初探[J]. 沉积学报, 25(1): 75-81.

The origin of dolostones discussed by means of thin sections staining, trace elements analyzing and isotopes testing, which existed together with lucutrine dark mudstone of Lucaogou Formation, middle Permian, Santanghu Basin. The Lucaogou dolostones were composed of lamellar algal dolostone and patchy dolostone. The characteristics of trace elements and stable isotopes indicated that the dolostones formed in the sedimentary environment with higher salinity, higher Ma/Ca ratio and strong reducibility. By analyzing the source of magnesium ion of Lucaogou dolostones, two types of origin were proposed. Lamellar algal dolostone was formed in quasicontemporaneous phase, and patchy dolostone formed with leaching dolomitization of volcanic material in burial diagenetic phase.

利用薄片染色、微量元素和稳定同位素测试等方法对三塘湖盆地中二叠统芦草沟组与湖相暗色泥岩共存的白云岩的形成机理进行了探讨。白云岩分为纹层状藻云岩和斑块白云岩两种类型。白云岩的微量元素和同位素特征表明其形成于较高盐度、高Mg/Ca比、强还原的沉积环境。通过对白云岩镁离子来源的分析，认为纹层状藻云岩形成于准同生期，而斑块白云岩则是在埋藏成岩期火山物质淋滤、交代作用下形成的。

2008

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廖静, 董兆熊, 翟桂云, 等. 2008. 渤海湾盆地歧口凹陷沙河街组一段下亚段湖相白云岩及其与海相白云岩的差异[J]. 海相油气地质, 13(1): 18-24.

渤海湾盆地歧口凹陷古近系沙河街组一段下亚段湖相白云岩主要为颗粒白云岩和泥晶白云岩两大类,常与泥质岩成薄互层或与其他碳酸盐岩互层产出.该湖相白云岩有序度较低,类似于海相准同生白云岩;Mg/Ca值偏离正常的化学计量值,具有富钙特征,说明其为快速交代的产物;碳氧同位素、Z值分析结果则反映了湖水的成化程度较高.根据低海平面期蒸发浓缩盐水在湖底形成密度层并向灰质沉积层中回流渗透导致白云石化发生的机理,建立了歧口凹陷沙一下亚段湖相白云岩的成因模式.湖相白云岩的分布特征及其与海相白云岩的差异分析表明,湖相白云岩具有分布面积小、白云石化作用不彻底等特征,油气储集性能较为局限.

2002

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林春明, 凌洪飞, 王淑君, 等. 2002. 苏皖地区石炭纪海相碳酸盐岩碳、氧同位素演化规律[J]. 地球化学, 31(5): 415-423.

对安徽巢湖凤凰山和南京孔山石炭系碳酸盐岩C、O稳定同位素进行了测定与研究.结果表明,苏皖地区石炭纪δ C、δ O记录是以四个同位素演化阶段为特征.在金陵组上部、和州组下部、黄龙组中下部和船山组层段, δ C表现出明显的正漂移,这可能是受植物和生物量增长、有机碳储藏量增加所引起的. Δ O记录总体上与δ C值呈相似的变化趋势. Δ O增加记录了气候变冷和冰川作用的结果, δ O负漂移与气候变暖和冰川消融是一致的.在浅水潮坪环境,大气淡水的淋滤作用使δ O值明显降低.

... 值越高(林春明等,2002) ...

1998

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... 这种壳体的分离和破碎现象可由水动力条件所致,即水动力强、冲刷严重,则壳体容易分离和破碎,此外,压实作用、沉积速率及化学溶蚀因素等也可影响到壳体的保存状态(刘传联等,1998),因此,难以单用介形虫壳体的破碎程度来准确推测其生存的环境条件 ...

2001

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... 70(刘传联等,2001) ...

1995

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1999

0.0

... 11(钱光人,1999) ...

1994

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裘松余, 卢兵力. 1994. 我国东部晚白垩世和早第三纪海侵与油气关系[J]. 地质论评, 40(3): 229-236.

Did transgressions occur during the Late Cretaceous and Early Tertiary in eastern China? And how were the transgressions related to hydrocarbons? The two questions are of interest to many geologists. Through many years of study of fora-minifers as well as other fossils such as Dinoflagellates, stromatoliths, Polychaeta burrows, marine ostrocods, bivalves, nannofossils and fishes, the authors hold that in the Late Cretaceous and Early Tertiary there occurred respectively two phases of transgression, which resulted in the formation of brackish deposits. They are as follows in ascending order: 1)the 1st member of the Qingshankou Formation in the Songliao basin in the Senomanian; 2 ) the 1st and 2nd members of the Nenjiang Formation in the Songliao basin and the Zhutian Member of the Nanxiong Forma-tion in the Nanxiong basin in the Turonian to early Senonian; 3 ) the 2nd member of the Taizhou Formation and Funing Formation i.n the Subei-South Yellow Sea basin, the 2nd member of the Buxin Formation in the Sanshui basin and the Yuan-Jiang Formation in the Dongting depression of the Jianghan basin in the Paleo-cene to early Eocene; 4 )the Chunhuazhen, Shahejie and Dongying Formations in the Bohai Gulf subsidence area, the Nadu Formation of the Baise basin and Nanning basin in the Beibu Gulf subsidence area and the Qianjiang and Jinghezhen Formations in the Qianjiang depression of the Jianghan basin in the late Eocene to Oligocene. These specious brackish deposits are favorable for the generation and accumulation of hydrocarbons, and mostly constitute the main source formations of the Mesozoic-Cenozoic petroleum-bearing basins in eastern China.

本文综合我国有关沉积和古生物资料，尤其对有孔虫的研究和对各门类化石资料的综合分析，认为我国东部晚白垩世和早第三纪各受过两期海侵，晚白垩世海侵主要发生在松辽盆地，，与早期海侵相应的半咸水沉积为青山口组一段，晚期相应的半咸水沉积如嫩江组一，二段，早第三纪古新世到始新世早期，与其相应的半咸水沉积，如：苏北－南黄海盆地泰州组二段和阜宁组，三水盆地布心组，江汉盆地洞庭坳隐沅江组。始新世晚期到渐新世，与其相应

... 研究区白云岩Z值均大于120(表 5),说明塘沽地区沙三段沉积时可能有海水阶段性地进入湖盆,导致湖盆水体的盐度不断增高,且前人对渤海湾盆地不同坳陷进行研究,也分别发现了大量海侵证据(裘松余和卢兵力,1994 ...

2011

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1994

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孙大鹏, 马育华, 李岫霞, 等. 1994. 我国盐湖卤水及其沉积物中稀土元素的初步研究[J]. 科学通报, 39(23): 2206-2207.

80年代以来,我国学者曾利用中子活化分析测定了海水及其沉积物中的稀土元素.日本学者曾利用中子活化分析方法测定了日本温泉水和火山口湖湖水中的稀土元素和铀钍元素.然而对高盐度的盐湖卤水及其沉积物的研究仍系首次.这对于了解高盐度水体中稀土元素的分布及其在盐湖资源的综合利用方面均有重要意义.

2004

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孙尚如. 2004. 泌阳凹陷湖相白云岩层序地层学分析[J]. 西北地质, 37(1): 30-35.

A suit of huge-thick dolomite formation was formed in the second and up-third of Hetao yuan Formation in Anpeng district of the center of lake-basin of Biyang depression.The main rocks are argillaceo us dolomite,dolomitic mudstone,mudstone,dolomite and trona formation.It is a perennial alkal escence saline sedimentary system.Based on the sedimentary charact eristics of lake-dolomite formation,the author first analyses the sequence of length-cycles,met aphase-cycles and short-cycles from the south to north section,and then the short-cycle and rhythm-cycle by high-resolution sequence stratigraphy method from the aspect of sediment and diagenesis.

泌阳凹陷湖盆中心安棚地区核二段和核三段上部发育一套巨厚白云岩层系地层,岩性以泥质白云岩、白云质泥岩、泥岩、纯白云岩和碱层为主,属淡化期和咸化期相互交替的常年碱性盐湖沉积体系。笔者从湖相白云岩层系沉积特征入手,首先从剖面上对长期旋回、中期旋回和短期旋回进行层序分析,然后从沉积成岩角度对该短期旋回和韵律旋回进行高分辨率层系地层分析。

2001

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谭荣, 黄思静, 赵霞飞. 2001. 冷家沙三段砂岩成岩序列与孔隙演化[J]. 沉积与特提斯地质, 21(1): 44-49.

笔者以辽河盆地冷家地区冷94井为例，通过铸体薄片、电镜扫描、能谱分析和阴极发光等分析和实验手段，对沙三段砂岩的成岩历史、成岩序列与孔隙演化及发展趋势进行研究。指出成岩阶段可划分为同生期→早成岩阶段早期→早成岩阶段晚期→晚成岩阶段早期。孔隙演化主要在压实作用，粘土矿物的包膜作用，方解石、白云石的胶结作用，长石溶蚀作用，石英的次生加大和微晶石英的沉淀作用等方面进行了研究，阐述并总结了它们互相之间的内在联系。 Abstract： Exemplified by the Leng-94 well in the Lengjia district, Liaohe Basin, the diagenetic history, diagenetic sequences and porosity evolution and trends are examined on the basis of thin-section, SEMP, energy spectrum and cathodoluminescence examination. The diagenetic stages may be divided into: (1) syndiagenesis; (2) early stage of early diagenesis; (3) late stage of early diagenesis, and (4) early stage of late diagenesis. The porosity evolution has been explored here in the aspects such as compaction, coatings of clay minerals, cementation of calcite and dolomite, solution of feldspar, secondary overgrowth of quartz and precipitation of microcrystalline quartz.

... 4 白云岩成因研究区白云岩的矿物成分主要为含铁白云石和铁白云石,这些富含铁质的白云石,一般形成于埋藏的还原成岩环境(谭荣等,2001 ...

2000

0.0

... 黄铁矿在研究区内较为普遍,其形成于同生期及准同生期,为还原条件下有厌氧细菌作用、介质pH值达9以上的环境的产物(田景春等,2000) ...

2005

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... 王冠民等,2005 ...

2008

0.0

1987

0.0

... CaO、MgO及FeO形成白云石,根据矿物学规定(王璞等,1987),当FeO含量大于MgO时,为铁白云石,而当FeO含量小于MgO时,为含铁白云石,故研究区白云石主要为铁白云石和含铁白云石,铁白云石中FeO含量为12 ...

2010

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... 第二,混层黏土中,蒙皂石向伊利石转化也会提供Fe²⁺(王婷婷,2010) ...

1986

0.0

... 白云石的人工合成实验及大量近代白云石沉积物的研究表明,多数白云石形成于较高温度(28~35 ℃或更高)条件下(夏文杰,1986) ...

2009

0.0

姚泾利, 王宝全, 王一刚, 等. 2009. 鄂尔多斯盆地下奥陶统马家沟组五段白云岩的地球化学特征[J]. 沉积学报, 27(3): 381-389.

Lower Ordovician Majiagou Formation in Ordos Basin is a shallow marine carbonate sequence with evaporate stratum. The centralwestern part in the basin often contains several dolomite units, which are major reservoir rock. Some researchers considered them as reflux dolomite near surface. However, petrography and geochemistry of dolomite suggest that this dolomite have evidence of burial origin. 〓〓Majiagou dolomite (M5) included dullred cathodoluminescence, trace element of 170 ~ 210 ppm for Mn and 5500 ~ 6200 ppm for Fe, stable isotopic oxygen composition of -7.093~-9.932 PDB, the average is -8.671 PDB, for matrix and vugfilling saddle dolomite and bright dolomite cement, stable isotopic strontium composition of 0.709 766~0.708 65 for 87Sr/86Sr (influenced by silicaclastics materialities, sea water). Dolomite replaced host rock along the fractures in the section. These data about Majiagou dolomite (M5) was formed in the burial condition. 〓〓REE pattern of dolomite are distinctly different from sea water, commonly are short of negative anomaly of Eu and Ce, such distinct REE signatures probably reflected interaction between diagenetic fluid and host rock and siliciclastic material. Homogenization temperature of 160℃～220℃, salinity of 5wt% ~ 25wt%, suggest dolomitization occurred at high temperature and larger pressure, replacing fluids is brines. 〓〓The pervasive dolomite, trace MVT mineral (sphalerites, galenas and iron sulfides), potassium(K)silicate mineral (Kfeldspar), quartz, volcanic tuffs, in these rock, which preserve a regional hydrothermal signatures. 〓〓The petrography and geochemistry of Majiagou dolomite show that this dolomite (M5) has evidence of hydrothermal dolomite (HTD) and central field (gas) are now identified to be of HTD type, typically with a strong structural control on localization. 

Chengdu University of Technology, Chengdu 610059

鄂尔多斯盆地奥陶系马家沟组马五段属于浅海碳酸盐层系，间夹蒸发岩层。盆地中东部通常含有白云岩，它们是主要油气储集层。一些研究者把它们看成近地表回流白云岩。然而白云岩的岩石学和地球化学表明这些白云岩具有埋藏成因的证据。 〓〓马家沟组白云岩（马五段）具有暗红色阴极发光，微量元素Fe为5 500×10-6～6 200×10-6，Mn为170×10-6~210×10-6，稳定同位素氧组分为-7.093‰～-9.932‰PDB，（平均值为-8.671‰PDB），稳定同位素锶（87Sr/86Sr）为0.709 766～0.708 65（有硅质碎屑物的放射性87Sr的影响）。薄片下可以看到白云石沿着裂缝交代，上述特征表明白云岩可能在埋藏条件下形成。 〓〓白云岩稀土元素的分布模式与海水的稀土元素分布有明显的差别，缺少Ce和Eu的负异常，表明交代流体不会是海水或蒸发海水。包裹体的均一化温度为160~220℃，盐度为5wt%～25wt%，暗示白云石化作用温度高，压力大，交代流体为卤水。 〓〓密西西比谷型（MVT）矿化作用（方铅矿和闪锌矿）以及共生的低温热液矿物——钾长石、萤石、石英、黄铁矿等表明白云岩具有区域热液特征。

... 2 埋藏调整阶段研究区不含铁的微晶白云岩,随着埋深加大,进入还原环境,因为只有还原态的二价铁才有可能取代MgCO₃中的Mg²⁺(姚泾利等,2009),所以这种条件下白云岩中的白云石容易生成稳定相的铁白云石和含铁白云石 ...

1993

0.0

叶德胜. 1993. 塔里木盆地北部震旦系至奥陶系白云岩的岩石学及地球化学特征[J]. 地球化学, 22(1): 1-9.

塔里木盆地北部震旦系至奥陶系白云岩是油气的主要储集岩类之一。震旦系白云岩中的各种颗粒、微晶基质、纤状胶结物及柱纤伏胶结物是准同生白云石化的产物,前三者为海水白云石化的结果, 后者为大气淡水或混合水白云石化的结果;细粒及粗粒状胶结物分别为大气淡水或混合水、埋藏环境中直接沉淀的白云石。寒武系至奥陶系的微晶白云岩、藻纹层白云岩及颗粒白云岩中的颗粒是准同生期海水潜流环境白云石化的产物;细至粗晶白云岩及颗粒白云岩及颗粒白云岩中的粗粒白云石胶结物是深埋藏成岩环境的产物。其间尚有许多过渡类型。

... ¹³C值均向高负值滑移(叶德胜,1993) ...

2008

0.0

伊海生, 林金辉, 赵西西, 等. 2008. 西藏高原沱沱河盆地渐新世—中新世湖相碳酸盐岩稀土元素地球化学特征与正铕异常成因初探[J]. 沉积学报, 26(1): 1-10.

The concentrations of rare earth elements(REE) and trace elements were analysed from MioceneOligocene lacustrine carbonates collected in the Tongtianhe section of Tuotuohe Basin of Tibetan Plateau. The total REE contents(∑REE) of lacustrine limestone and dolostones covers a wide range:36.23×10-6～189.64×10-6 and its average value of 28 samples is 78.58×10-6. The shalenormalized REE patterns display middle REE enrichments and strong positive Eu anomalies. The relatively high Eu/Eu* ratios occur across the Oligocene and Miocene boundary layers. This is the first report of positive Eu anomalies observed in REE patterns in terrestrial sediment records. Based on REE distributions and covariance between Eu and Ba, this paper presents Eu anomaly in lacustrine carbonate samples of the study area implies hydrothermal venting occurrence in paleolake systems.

Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu 610059

对采自沱沱河盆地通天河剖面渐新世雅西措群和中新世五道梁群地层中的湖相灰岩和白云岩样品进行了稀土元素和微量元素分析。研究结果表明，湖相碳酸盐岩稀土元素总量（∑REE）变化于36.23×10-6～189.64×10-6，28件样品平均值为78.58×10-6。稀土元素的页岩标准化配分形式具有中组稀土富集的特点，正铕异常极为明显，在渐新统与中新统界线处Eu/Eu*比达到最大值7.15，这也是首次在陆地湖泊沉积记录中观察到的正Eu异常。根据稀土元素的分布以及Eu与Ba含量的同步变化特点，提出该区湖相碳酸盐岩中Eu的异常富集可能与湖底喷流热水有关。 

... 3 稀土元素分析湖相碳酸盐岩的稀土元素分布特征可以反映陆地古湖泊水体的水文地球化学状态和演变过程(伊海生等,2008) ...

... Eu³⁺在还原条件下很容易还原成Eu²⁺,后者常与Ca²⁺一起沉淀,因此,黏土矿物富集的湖相沉积岩中易出现Eu亏损,而Eu正异常的湖相碳酸盐岩则被认为与湖底喷流热水有关(伊海生等,2008) ...

2008

0.0

袁文芳, 曾昌民, 陈世悦. 2008. 济阳坳陷古近纪咸化层段甲藻甾烷和C₃₁甾烷特征[J]. 沉积学报, 26(4): 683-687.

The study on chromatography mass analysis of saturated hydrocarbons in Paleogene saline formation of Jiyang Depression shows that dinosterane and C31sterane developed in source rocks of the 1st member（Es1）, the 3rd member（Es3）and upper the 4th member（EsU4）of Shahejie Formation, these molecular fossils are marks of marine transgression, moreover C31sterane denotes that the formation is influenced more by sea water, therefore salinity of 3 members related to marine transgression.

Institute of Exploration and Development , PetroChina Tarim Oil field Company , Kuerle Xinjiang 84100

通过对济阳坳陷古近纪咸化层段源岩的饱和烃色谱质谱分析发现，沙河街组一段、沙三段和沙四段上亚段源岩中发育了可以指示海侵发生的甲藻甾烷和C31甾烷分子化石，并且C31甾烷通常出现在水体盐度更高、海侵程度更大的环境中，从而推测三个层段的咸化与海相关。

... 袁文芳等,2008) ...

2009

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张霞, 林春明, 凌洪飞, 等. 2009. 浙西地区奥陶系砚瓦山组瘤状灰岩成因探讨[J]. 古地理学报, 11(5): 481-490.

In this paper，we discussed the genesis of the nodular limestones from the Ordovician Yanwashan Formation in the Huangnitang section(the first GSSP)，Changshan，Zhejiang Province on the basis of mineral component，texture，structure，chemical composition，and particularly the stable C-O isotopic composition of both the nodule and matrix. The research results indicate that there is an apparent difference between the nodule and matrix of the nodular limestones. The nodules are mainly composed of micritic calcite(70％～98％)，while the primary component of the matrix is clay mineral(40％～78％)with only 20％～58％ calcite. The δ 13 C VPDB values of calcite of the nodule and matrix are 0.5‰ to 1.4‰(average 0.9‰)and -0.4‰ to 1.1‰(average 0.2‰)，respectively. The δ 18 O VPDB values of calcite of the nodule and matrix are -12.8‰ to -8.0‰(average -10.6‰)and -11.7‰ to -9.0‰(average -10.3‰)，respectively. The nodule always shows higher δ 13 C value and formation temperature than those of the matrix for the same sample. All features imply that the nodular limestones from the studied section are formed due to a combined processes of the periodical dissolution of bottom current during the sedimentary period and the differential compaction and pressure solution during the diagenesis. There are three existing types of the nodular limestones: banded nodular limestone，discontinuous nodular limestone and random nodular limestone. The occurrence mode of the nodular limestone is determined by the insoluble residue content of country rock of nodules and the pressure solution intensity.

1 State Key Laboratory for Mineral Deposits Research，School of Earth Sciences and Engineering， Nanjing University，Nanjing 210093，Jiangsu 2 Planning & Designing Institute of East China Branch，SINOPEC，Nanjing 210036，Jiangsu

对浙江常山黄泥塘剖面奥陶系砚瓦山组瘤状灰岩中瘤体和基质的矿物组成、结构、构造、化学成分及碳氧同位素等做了系统研究，并从其基本特征、尤其是碳氧同位素特征出发，结合前人研究成果，对瘤状灰岩的成因进行了初步探讨。研究表明，瘤状灰岩的瘤体和基质存在明显差异：瘤体主要由方解石组成（70％～98％），基质则以黏土矿物为主（40％～78％），方解石次之（20％～58％）；瘤体和基质的 δ 13 C VPDB 值分别为0.5‰～1.4‰和-0.4‰～1.1‰，平均值分别为0.9‰和0.2‰， δ 18 O VPDB 值分别为-12.8‰～-8.0‰和-11.7‰～-9.0‰，平均值分别为-10.6‰和-10.3‰；每个样品中瘤体的碳同位素值和形成温度均比基质高。黄泥塘剖面砚瓦山组瘤状灰岩是沉积物沉积时期周期性底流溶解和成岩过程中差异性压实和压溶共同作用的产物，瘤体原岩中非碳酸盐组分含量及后期压溶作用强度的差异导致瘤状灰岩不同的存在形式，有条带状、断续状和杂乱状3种。

... 张霞等,2009) ...

2000

0.0

张晓宝, 王志勇, 徐永昌. 2000. 特殊碳同位素组成白云岩的发现及其意义[J]. 沉积学报, 18(3): 449-452.

According to publications, the δ 13 C value of the dolostones mainly ranges from -5‰ to +5‰ in a geological history except the Precambrian and Tertiary. However, we obtained some data of the dolostones which are more enriched in 13 C than +5‰ when we researched the dolostones in the Upper Permian Lucaogou Formation. The δ 13 C value of the dolostones varies in the range from +7.3‰ to +17.9‰ with an average of +11.7‰(7) and that of the dolomites from +7.9‰ to +16.1‰, averag +11.6‰(5). Based on the data of regional geology, petrology, mineralogy of the Upper Lucaogou Formation, the carbon isotopic characteristics of CO 2 from modern sedimentary sections in oceans and lakes and the simulation of bacterial process and carbonate minerals in ancient sedimentary sections we analyzed the distribution characteristics of the dolostones and considered that except higher buried rate of the global Permian living things and higher salinity of the researched area the anomally 13 C-enriched dolosdones are mainly due to the formation of 13 C-depleted CH 4 and 13 C-enriched CO 2 ed till now, but as one of possible sources of natural gas attention should be paid to it.

据现有文献报导,除前寒武系和第三系外,地史时期中白云岩δ 13 C值主要分布在-5‰～+5‰的范围。但是,作者在研究准噶尔盆地上二叠统芦草沟组白云岩碳同位素时获得了一批高度富集13C的资料,其中白云岩δ 13 C分布于7.3‰～ 17.9‰,平均11.7‰(7);白云石δ 13 C介于7.9‰～16，平均11.6‰(5)。根据区域地质、岩石学和矿物学资料，结合现代沉积剖面、细菌作用模拟实验和古代沉积剖面碳酸盐矿物碳同位素特征，分析了白云岩分布特征。作者认为白云岩中如此高的富集除了全球二叠纪生物埋藏速率较快和研究区古盐度较高外，更主要的因素应与厌氧条件下发酵带内细菌作用引起有机物质碳同位素分馏，形成贫的和富的有关。这一过程进行得愈充分，沉积介质中富集的的浓度越高，形成的白云岩碳同位素组成越重。同时，只有这一作用持续存在才能形成大量富的与黑色页岩互层的白云岩。这一现象从一个侧面说明在芦草沟组沉积时有一个持续时间较长的细菌活动时期，从而，生成了数量可观的以甲烷为主的生物气。由于生物气形成时代较老，易于扩散逸失，它们难于单独成藏保存至今，但作为天然气复合成藏来源之一，则应予关注。

... ¹³C富集与生物埋藏速率较快(Schoelle and Arthur,1980)和湖水盐度较高(张晓宝等,2000)有关,结合塘沽地区沙三段沉积环境,推测该区这种#cod#x003b4 ...

2003

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... 张枝焕等,2003) ...

2010

0.0

... ¹⁸O 值与准同生回流渗透白云岩特征(郑剑锋等,2010)相似 ...

1995

0.0

... 薄片观察及X射线衍射分析表明,白云岩中主要矿物组分除铁白云石、含铁白云石外,还含有较多黏土矿物及方沸石(图 3-b),其中黏土矿物主要为伊蒙混层和伊利石,还含有少量绿泥石及高岭石,方沸石多呈微晶粒状,通常与泥质组分互成纹层(图 3-c),也有少量为粉晶粒状,且多充填在裂缝中,粒间可含油(图 3-d),推测这些方沸石为碱性环境中化学沉积或胶体转变而成的产物(周建民等,1995) ...

2010

0.0

... 其原因可能是由于随着原子数的增加,稀土元素的稳定程度也增强,轻稀土优先被有机质、黏土碎屑等吸附进沉积物中,而重稀土则形成稳定络合物滞留在成岩流体中(朱丽霞等,2010) ...

1973

0.0

... 之间变化(Badiozamani,1973) ...

1964

0.0

1988

0.0

... 现代湖泊中碳酸盐岩碳氧同位素研究发现,开放型淡水湖泊的碳氧同位素投点多落在第三象限,如瑞士Greifensee湖、美国Henderson湖和以色列Huleh湖(Talbot,1990),封闭性湖泊的碳氧同位素投点多落在第一、二象限,如北美Great Salt Lake、非洲的Turkana、Natron-Magadi湖(Kelts,1988) ...

1997

0.0

... Li and Ku,1997),一般封闭性湖泊中的相关系数大于0 ...

1980

0.0

... ¹³C富集与生物埋藏速率较快(Schoelle and Arthur,1980)和湖水盐度较高(张晓宝等,2000)有关,结合塘沽地区沙三段沉积环境,推测该区这种#cod#x003b4 ...

1990

0.0

... ¹³C值之间呈明显的同步相关变化,封闭性越强,相关系数越大(Talbot,1990 ...

1974

0.0

... ¹⁸O 值也接近于零(Veizer and Compston,1974) ...

1980

0.0

... 目前世界上近60%的油气都储存在碳酸盐岩中,其中白云岩在碳酸盐岩储集层中占50%,北美地区比例可达80%(Zenger et al ...