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<sup>*</sup>

钱一雄, 何治亮, 李慧莉, 陈跃, 金婷, 沙旭光, 李洪全. (2017)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^* [J]. 古地理学报, 19(2): 197-210
Qian Yixiong, He Zhiliang, Li Huili, Chen Yue, Jin Ting, Sha Xuguang, Li Hongquan. (2017)Discovery and discussion on origin of botryoidal dolostone in the Upper Sinian in North Tarim Basin[J]. Journal Of Palaeogeography, 19(2): 197-210. DOI:10.7605/gdlxb.2017.02.016 复制到剪切板

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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^*

钱一雄¹, 何治亮², 李慧莉², 陈跃¹, 金婷³, 沙旭光⁴, 李洪全⁴

1 中国石化石油勘探开发研究院无锡石油地质研究所,江苏无锡 214126。

2 中国石化石油勘探开发研究院,北京 100083。

3 中国石化江苏油田分公司采油二厂,江苏金湖 211600。

4 中国石化西北油田分公司石油勘探开发研究院,新疆乌鲁木齐 830011

第一作者简介钱一雄,男, 1962年生,博士,教授级高级工程师,现在中国石化石油勘探开发研究院无锡石油地质研究所工作,研究方向为碳酸盐岩沉积与储集层研究。通讯地址: 江苏省无锡市滨湖区蠡湖大道 2060号;邮政编码: 214126。 E-mail: qyx9167@vip.sina.com。

收稿日期:2016-12-01

基金:*联合基金(编号: U1663209)及国家重点基础研究发展规划“973”项目(编号: 2012CB214802)与国家科技重大专项(编号: 2011ZX05005~002,2011ZX05008~003~11)联合支持; Co-funded by MST: Ministry of Science and Technology(No. U1663209),National Basic Research Program(973 Program) of China (No.2012CB214802)and National Science and Technology Major Project(No.2011ZX05005-002, 2011ZX05008-003

摘要

“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、δ Ce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。

关键词: 皮壳—葡萄状白云岩; 微区碳氧同位素; 奇格布拉克组; 震旦系; 塔里木盆地

文献标志码:A 文章编号:1671-1505(2017)02-0197-14

Discovery and discussion on origin of botryoidal dolostone in the Upper Sinian in North Tarim Basin

Qian Yixiong¹, He Zhiliang², Li Huili², Chen Yue¹, Jin Ting³, Sha Xuguang⁴, Li Hongquan⁴

1 Wuxi Institute of Petroleum Geology,Petroleum Exploration & Production Research Institute,SINOPEC,Wuxi 214126,Jiangsu

2 Petroleum Exploration & Production Research Institute,SINOPEC,Beijing 100083

3 No.2 Oil Production Factory,Jiangsu Oilfield Company,SINOPEC,Jinhu 211000,Jiangsu

4 Petroleum Exploration & Production, Research Institute,Northwest Company,SINOPEC,Urümqi 830011,Xinjiang

About the first author Qian Yixiong,born in 1962,Ph.D.,a senoir researcher at Wuxi Institute of Petroleum Exploration & Production Research Institute,SINOPEC. He is mainly engaged in carbonate rocks and reservoirs. Address: No.2060, Lihu Avenue,Binhu district,Wuxi,Jiangsu Province,214126. E-mail: qyx9167@vip.sina.com.

Abstract

The botryoidal dolostone of a unusual textures features in Qigebulake Formation,in the Upper Sinian developed at Dong'ergou section and Well XH 101 of northern Tarim Basin,has been firstly reported. Constraining its origin based on lithology and geochemical data,the shell-comb or botryoidal dolostone,which consists of shrub fibrous cement,bladed radial as well as granular dolomite crystal with alternately dark and luminescent and zonation,the average of botryoidal dolostone ofδ13CPDB is 2.50‰(1.80‰~3.16‰),δ18OPDB is-3.30‰(-6.40‰~0.86‰),⁸⁷Sr/⁸⁶Sr is 0.7091(0.7089~0.7096),compared with the values of matrix dolostone. The botryoidal dolostone have rather high positive ofδ18OPDB and⁸⁷Sr/⁸⁶Sr(within the change values of coeval normal sea-water: 0.7087~0.7094)with a similarδ13CPDB. The δ¹³C and δ¹⁸O of zonation varies from the dark rimming to the luminescent centre varies slightly decreasing or increasing,while the strong negative deplete of δ¹³C and δ¹⁸O in outer of zonation,shows the tendency of negative deplete of δ¹³C and δ¹⁸O and increasing of⁸⁷Sr/⁸⁶Sr and Mn,decresing of the contents of Al₂O₃ 、Fe₂O₃、Na₂O+K₂O、P₂O₅、Sr/Ba、Fe/Mn. Coupled with a higher dolomitization. The contents of Al₂O₃、Fe₂O₃ 、MnO are relatively lower,and Na₂O+K₂O,P₂O₅,Sr,Hg,Cu,and the ratios of Sr/Ba,Sr/Mn are higher in comparison with the values of matrix dolostone. The contents of REE(10.21×10^-6~15.75×10^-6)with the “Left-leaning”distribution pattern of rare earth elements with LREE depletion,heavy REE enrichment,strong negative CE anomaly,indicated that the botryoidal dolostone was formed either in a well-preserved,weak reduction and oversaturated sea water environment with an increasing of pH value and free oxygen contents in sea waters. Or in a residual sea water of pore fluids in the early stage of diagenesis or shallow buried environment,later partly superimposed by a cyclic subaerial-exposed fresh water.

Key words: botryoidal dolostone; δ 13C and δ;18O of microdrill-samples; Qigebulake Formation; Sinian; Tarim Basin

Show Figures

皮壳、栉壳状或葡萄状白云岩, 是由直径大者8~10, cm和小者不到1, mm的玛瑙纹带或条带状构造、波状富含有机质的暗色层和纤柱状— 粒状亮晶白云石浅色层交替组成, 往往沿层面、裂隙或孔洞中呈“ 钙华” 状分布。前人对四川盆地及扬子地区的上震旦统灯影组的“ 皮壳— 栉壳状、雪花状或葡萄状白云岩的成因进行了详细的研究。主要认识有: (1)非叠层石生态系的兰细菌构成(张荫本, 1980; 方少仙等, 2003; 郝毅等, 2015; 牟传龙等, 2015), (2)大气水潜流带成因(刘怀仁等, 1991; 向芳等, 1998; 陈明等, 2002; 施泽进等, 2011), (3)多种成岩下产物(方少仙等, 2003; 张杰等, 2014)。虽对柯坪地区的下寒武统— 上震旦统发育的藻白云岩或微生物岩已有研究报道(王小林等, 2010; 宋金民等, 2012; 罗平等, 2013), 至今未曾见有关葡萄状白云岩的报道。本文报道了在阿克苏市西南约30, km的东二沟以及塔北星火101井的上震旦统奇格布拉克组中发现的葡萄状— 皮壳白云岩、少量含云质灰岩基本特征, 它可在早期海水中形成, 或在早期成岩或浅埋藏过程中孔隙内的残余海源流体中形成, 部分经历了较强的大气水作用改造。

1 地质特征

上震旦统奇格布拉克组(Z₂_s)是张太荣(张师本等, 2003)所厘定的, 包括原苏盖特布拉克组上部和肖尔布拉克组下部。高振家等(1985)重新厘定了涵义, 仅包括了肖尔布拉克组下部的白云岩, 厚度141~195, m, 为一套滨海— 浅海相的沉积。东二沟剖面位于阿克苏西南约30, km, 地理坐标为北纬40° 59.29'19″; 东经80° 00'2.22″; 而星火101井位于新和县西南约35, km沙西凸起上(图 1), 肖尔布拉克剖面上的奇格布拉克组中上段均有叠层石发育, 以纹层状组构为主、凝块状组构和隐微生物岩次之。主要为侧向断续的水平、波状、半椭球和半球形的由蓝细菌组成的微生物席, 呈丘状、杂乱状、角砾状, 指示潮下带低水动力— 能量相对高的潮间至潮上带的浅水环境(钱一雄等, 2014)。

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	图1 塔里木盆地北部上震旦统东二沟剖面图与星火101井采样位置及柱状图Fig.1 Location of geological Dong'ergou section and Well XH101, sampling and lithological column of botryoidal dolostone in the Upper Sinian of northern Tarim Basin

东二沟奇格布拉克组的顶部中厚层藻纹层云岩及叠层石中, 不规则形的皮壳状、葡萄状白云石中, 发育了大小为1.5~2.5, cm不规则缝洞, 充填了不同期次的白云石及粗巨晶方解石, 有以下2类组合: (1)边缘为栉壳状— 皮壳状白云石, 由2~3层的明、暗互层的纤状白云石, 中心为粒状中粗晶方解石; (2)呈纹层条带的灰白— 白色细晶— 中粗晶白云石(图 2-a, 2-b)。而星火101井中奇格布拉克组中上部发育了呈皮壳状、肾状和葡萄状粉细晶白云石集合体, 直径为0.5~1.0, mm(图2-c)。

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	图2 塔里木盆地北部东二沟剖面及星火101井中上震旦统奇格布拉克组(Z₂q)皮壳状、葡萄状白云岩及缝洞充填物特征Fig.2 Textural components of shell-comb or botryoidal dolostone and sampling location in Qigebulake Formation at Dong'ergou section and Well XH 101, northern Tarim Basin

2 分析方法

本次室内研究包括以下的主要采样及分析测试项目及批次: (1)阿克苏东二沟12件、星火101井14件, 共计薄片和铸体26件; (2)阴极发光共6件; (3)选送白云岩及缝洞白云石有序度6件; (4)全岩及缝洞充填物的碳氧同位素共41件(包括微区件), 其中, 阿克苏东二沟29件、星火101井22件; (5)锶同位素21件, 其中, 东二沟11件、星火101井10件; (6)常量、微量及稀土元素地球化学分析共10件, 其中, 阿克苏东二沟8件、星火101井2件。白云石有序度分析由成都理工大学油气藏地质及开发工程国家重点实验室完成, 使用仪器为D/max-2500型X射线衍射仪。阴极发光鉴定是在中国石化石油勘探开发研究院构造与沉积储集层实验室完成、所用仪器为BLM-3RX型阴极发光仪。

碳氧稳定同位素是由国家地质实验测试中心矿床所完成, 采用McCrea(1950)100%正磷酸法和Finngan-MAT252气体质谱仪, 分析精度± 0.2‰ 。首先将样品置温箱中烘干, 然后在真空中与 100%的正磷酸反应, 平衡温度50, ℃, 平衡时间24 h。CO₂气体的碳、氧同位素测定由质谱计MAT251EM; 国际标准V-SMOW, 分析精度为± 0.2‰ ; 根据δ _PDB=0.97δ _V-SMOW-30.0换算, 分析精度优于± 0.10%。微区碳氧同位素分析采用牙钻钻头直径为1, mm, 并标定为对应(原位)阴极发光图像、将钻取的样品再研磨至小于200目, 方法同上, 由中国科学院地质与地球物理研究所完成。锶同位素是由核工业地质研究院测试中心完成。采用仪器为ISOPROBET热电离质谱仪, 测量精度优于3× 10^-6。

岩石化学是由中国地质科学研究院地球物理地球化学研究完成。样品在研磨成粉末前用去离子水清洗; 清洗后, 研磨至200目以下。常量元素中的Ca采用X射线荧光光谱法(XRF)(本次分析中未测SiO₂); Hg和As为原子荧光光谱法(CV-AFS); 其他常量、微量元素和稀土元素用等离子体质谱法(ICP-MS)和等离子体光谱法(ICP-OES)测定。采用标样为GSD-5、GSD-6、GSD-13, 常量元素分析误差小于0.1%; 微量元素的分析误差(包括稀土)在± 1× 10^-6。

3 测试结果

3.1 岩石学

镜下及阴极发光观察发现: 沿壁发育了成层性或放射状的暗色纹层、纤维状泥粉晶白云石、环沟壁对称向心生长, 中心或中部为粉细晶亮晶白云石(图 3-a, 3-b, 3-c)。泥粉细晶基岩(matrix)白云石中发育了球形、似球形、杆形、蘑菇形、孢子形或瘤状等蓝细菌; 可单列向上生长的串珠状、螺旋状, 或树杈状或棒状群体或由孢子构成的镶嵌状(图 3-d)。可能反映了沉积或早成岩期的蓝细菌的生态; 受成岩作用影响, 仅在近中心部位残留了不发光的富含有机质的蓝细菌外形, 构成微观上的“ 葡萄石” (图 3-a, 3-e); 而在颗粒之间或包绕白云岩碎屑颗粒向四周发育了数量较多的球形、水滴形、杆形、孢子形等, 由于亮晶胶结物淀速度慢, 颗粒外的兰细菌薄膜较厚, 包绕碎屑颗粒生长形成团块状的“ 葡萄状” 白云石组构、总体呈泡沫状结构(foam texture)、而“ 雾心亮边” 中大部分颗粒核部不发光、菱柱形或不规则形白云石(原为蓝细菌)、边部发亮橙黄色; 同时还存在呈不发光的斑点或斑块, 类似于较为生物膜或、不规则聚集体的原地钙化斑状物(凝块)或生物层孔状构造遗迹, 推测为球状蓝细菌微生物占优势的微生物群落所形成(Flü gel, 2004; Gerdes, 2007, 2010)。沿纹层环沟壁对称向中心生长的亮晶白云石可能是表生大气水作用下的产物(图 3-a, 3-d)。

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	图3 塔里木盆地北部东二沟剖面及星火101井中上震旦统奇格布拉克组(Z₂q)皮壳状、葡萄状白云岩光性及CL图像Fig.3 Textural components of dolomite phases for shell-comb or botryoidal dolostone in Qigebulake Formation at Dong'ergou section and Well XH101, northern Tarim Basin

阴极发光有以下4类情形: 基质的泥粉晶云岩, 发暗色橙红色光; 层纹— 条带状的“ 纤状与树枝状” 粉细晶白云石, 具明显的明暗发光及环带状亮橙红色; 刃状(BCD-bladed cement)— 细晶(粒)白云石, 发中等橙红色光; 核部为中粗晶方解石(RCD: Rhomb cement dolomite)或中细晶白云石, 发光较暗或不发光(图 3-c, 3-f)。

对基质、葡萄状以及缝洞中不同充填物不同结构类型白云石可划分为: 泥粉晶(D00)或葡萄状泥粉晶白云石及含云质灰岩(D01); 可细分纹层与栉壳带边缘的纤状— 刃状白云石(D010)、外壳或环带中粉细晶白云石(D011); 粉细晶白云岩(D2)、中细晶白云岩(D3)、中粗晶云岩(D40)或孔洞中的中细晶白云石(D41)、巨粗晶白云石(D50)、孔洞中的中粗晶白云石及含云的方解石(D51)、裂缝的中粗晶— 巨晶白云石(D6)和缝洞中的中粗晶— 巨晶方解石(C7)。白云岩有序度分析表明: 基质中的粉细晶白云岩D1的δ 值为0.63~0.78, 平均为0.72(n=5); 而葡萄石状白云岩D01中的δ 值为0.79, 比前者稍高。

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图4 塔里木盆地北部东二沟及星火101井奇格布拉克组(Z₂q)基质、皮壳状、葡萄状白云岩及缝洞充填物的碳、氧同位素(左)和锶同位素值(右)Fig.4 Date of

\begin{matrix} δ^{13} C_{PDB} \end{matrix}

and

\begin{matrix} δ^{18} O_{PDB} \end{matrix}

(left), ⁸⁷Sr/⁸⁶Sr(right) for matrix, shell-comb or botryoidal dolostone and different-type dolomites and various minerals filled in pores or vugs and fractures in Qigebulake Formation at Dong'ergou section and Well XH101, northern Tarim Basin

3.2 碳氧及锶同位素

按上述2个剖面中的不同白云岩(化)及缝洞充填物的不同成岩矿物同位素对比( 表 1)不难看出: (1)东二沟中基岩中比星火1井对应值负偏明显、也存在负偏, 反映了前者大气水作用影响较强; (2)与基质白云石相比, 葡萄— 皮壳状白云石及含云质灰岩中相似, 少量呈稍低或稍高; 但正偏较为明显, ⁸⁷Sr/⁸⁶Sr 相对较高; (3)葡萄— 皮壳状白云石及含云质灰岩中平均的 ⁸⁷Sr/⁸⁶Sr=0.7091(70887~0.70939)、与震旦纪海水(0.7087~0.7094, Halverson et al., 2007)相似; (4)随着白云石结晶程度或缝洞充填物的晶体大小增加, 与基岩相比, 其、负偏明显, ⁸⁷Sr/⁸⁶Sr 值逐渐增加; 反映了大气水、壳源或其他成岩流体介入水— 岩反应过程。通过对比葡萄— 皮壳状白云石及含云质灰岩与基岩相比的、正偏为主的特征, 可推测其早期生长环带主要在海水是形成, 后期有大气淡水作用。

表1 塔里木盆地北部东二沟及星火101井奇格布拉克组(Z₂q)基质、皮壳状、葡萄状白云岩及缝洞中不同充填物碳氧及锶同位素分析 Table1 Data of

\begin{matrix} δ^{13} C_{PDB} \end{matrix}

\begin{matrix} δ^{18} O_{PDB} \end{matrix}

and ⁸⁷Sr/⁸⁶Sr formatrix, shell-comb or botryoidal dolostone and various minerals filled in pores or vugs and fractures in Qigebulake Formation at Dong'ergou section and Well XH101, northern Tarim Basin

样号	样品	$\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ ‰	$\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ ‰	⁸⁷Sr/⁸⁶Sr
DEG-Z₂q-1-1	皮壳状粉晶云岩D01	2.60	-5.80	0.70887
DEG-Z₂q-1-2	细晶白云岩D2	2.30	-6.90	0.70924
DEG-Z₂q-1-3	粗晶白云岩D40	1.20	-7.50	0.70907
DEG-Z₂q-1-1^*	葡萄状云岩(核)D011	1.91	-6.18
DEG-Z₂q-1-2^*	葡萄状云岩内层D010	1.98	-6.20
DEG-Z₂q-1-3^*	葡萄状云岩外层D010	2.57	-6.35
DEG-Z₂q-1-4^*	葡萄状云岩外层D010	1.89	-6.28
DEG-Z₂q-1-5^*	葡萄状云岩核中洞D5	2.46	-12.34
DEG-Z₂q-2-1	皮壳状含云质灰岩D01	1.80	-6.40	0.70901
DEG-Z₂q-2-2	巨粗晶白云岩D5	-0.70	-8.90	0.70888
DEG-Z₂q-2-③	粗巨晶方解石C7	-2.60	-13.80	0.70990
DEG-Z₂q-2-1^*	葡萄状粉晶云岩(核)D011	1.19	-6.79
DEG-Z₂q-2-2^*	中细晶白云岩D41(孔洞)	0.23	-9.02
DEG-Z₂q-3-①	皮壳状粉晶云岩D01	1.90	-5.00	0.70891
DEG-Z₂q-3-②	巨粗晶白云岩D50	0.70	-10.80	0.70975
DEG-Z₂q-3-1*	粉晶白云岩D00	2.51	-3.09
DEG-Z₂q-3-2*	栉状粉细晶白云岩D2	0.80	-5.98
DEG-Z₂q-3-3*	细晶白云岩D2(边缘)	0.85	-8.11
DEG-Z₂q-3-4*	中细晶白云岩)D3(中心)	1.07	-9.79
DEG-Z₂q-4	巨粗晶云灰岩D40	-0.90	-10.10	0.71000
DEG-Z₂q-4-1*	葡萄状藻云岩(外壳)D010	2.29	-3.08
DEG-Z₂q-4-2*	粉晶白云岩(壳缘)D00	1.90	-3.83
DEG-Z₂q-4-3*	粉细晶白云岩(栉状)D2	1.87	-4.40
DEG-Z₂q-4-4*	细晶白云岩(栉间)D2	0.77	-8.78
DEG-Z₂q-4-5*	中细晶白云岩(孔洞)D41	1.07	-9.93
DEG-Z₂q-5-①	粗巨晶方解石C7(孔洞)	-1.90	-12.80	0.70968
DEG-Z₂q-5-②	粗晶白云岩D50	-0.70	-8.50
DEG-Z₂q顶-001	泥粉晶云岩D00	2.00	-5.40	0.70939
DEG-Z₂q-5-1*	巨晶方解石C7(孔洞)	-5.50	-13.64
XH101-001(5974.89, m)	粉晶云岩D00	3.50	-2.50	0.70926
XH101-2-1^*(5973.97, m)	巨晶方解石C7(孔洞)	0.47	-9.91
XH101-2-2^*(5973.97, m)	粉细晶云岩D2	3.95	-2.01
XH101-004(5966.11, m)	泥粉晶云岩D00	3.50	-3.70	0.70293
XH101-4-1^*	细晶方解石C7(裂隙)	0.73	-8.93
XH101-4-2^*	粉晶云岩D00	4.25	-1.56
XH101-006(5964.22, m)	中晶白云石D51(裂隙)	-0.80	-13.80	0.71777
XH101-007-1(5963.5, m)	粉晶云岩D00	3.10	-3.00	0.70906
XH101-007-2(5963.6, m)	中晶白云石D51(裂隙)			0.71909
XH101-009(5945.21, m)	粉晶云岩D00	3.00	0.20	0.70889
XH101-010(5927.85, m)	粉晶云岩D00
XH101-011-1(5927.75, m)	条纹状粉晶云岩D00	2.50	0.20	0.70897
XH101-011-2(5927.75, m)	中粗晶白云石D51(孔洞)	0.80	-7.20	0.70982
XH101-11-1^*	藻细晶白云石D2(洞心)	1.90	-5.60
XH101-11-2^*	藻粉细晶D21(溶洞边缘)	3.00	-1.78
XH101-11-3^*	条纹状粉晶云岩D00	3.04	0.52
XH101-12-1-1^*	细晶白云石(藻团)D21(溶洞中心)	1.04	-6.67
XH101-12-1-2^*	粉细晶Dol(藻团)D21(溶洞边缘)	2.46	-1.61
XH101-12-1-3^*	葡萄状藻云岩D01	3.16	0.86
XH101-12-2-1^*	葡萄状藻云岩(壳外)D010	1.92	-3.82
XH101-12-2-2^*	葡萄状藻云岩(洞)D011	1.77	-5.48	0.71000
XH101-12-2-3^*	葡萄状藻粉晶云岩D01	3.07	-0.16	0.70967

注: “ * ” 表示微区数据。

表1 塔里木盆地北部东二沟及星火101井奇格布拉克组(Z₂q)基质、皮壳状、葡萄状白云岩及缝洞中不同充填物碳氧及锶同位素分析 Table1 Data of

\begin{matrix} δ^{13} C_{PDB} \end{matrix}

\begin{matrix} δ^{18} O_{PDB} \end{matrix}

若按白云石成岩序列的碳氧同位素值为(表 2): (1)D00(泥粉晶)及D1-D2(粉细晶): $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 平均为3.04‰ (n=9, 2.50~4.25)、 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 平均为-2.29‰ (n=9, -5.40‰ ~0.20%)、 ⁸⁷Sr/⁸⁶Sr 平均为0.70808(n=6, 0.70293~0.70930); (2)D01(皮壳状、葡萄状粉晶云岩及少量含云质灰岩: $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 平均为2.50‰ (n=5, 1.80~3.16)、 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 平均为-3.30‰ (n=5, -6.40~0.86)、 ⁸⁷Sr/⁸⁶Sr 平均为0.7091(n=4, 0.7089~0.7096); (3)D2(细晶): $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 平均为1.83‰ (n=4, 0.23~3.95)、 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 平均为-6.51‰ (n=4, -9.02~-2.01)、 ⁸⁷Sr/⁸⁶Sr 为0.7092; (4)D41-D51(孔洞中中细晶与中粗晶云岩及少量云灰岩):

$\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ ‰ 平均为0.070‰ (n=6, -0.9~1.20)、 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 平均为-8.83‰ (n=6, -10.80~-7.20)、 ⁸⁷Sr/⁸⁶Sr 平均为0.7095(n=5, 0.7089~0.7100); (5)D6(裂隙中的中粗晶): $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 为-0.80‰ 、 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 为-13.80‰ 、 ⁸⁷Sr/⁸⁶Sr 平均为0.7184(n=2, 0.7191~0.7178); (6)C7: $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 平均为-2.38‰ (n=4, -5.5~0.47)、 $\begin{matrix} δ^{18} {O_{PDB}}_{平} \end{matrix}$ 均为-12.54‰ (n=4, -11.80~-9.91)、 ⁸⁷Sr/⁸⁶Sr 平均为0.7098(n=2, 0.7096~0.7099)(详见表1)。所有分析样品 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 与 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 关系图上(图 4), 基本呈线性相关, 反映总体经历了大气水改造作用的结果。

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图5 塔里木盆地北部东二沟及星火101井中的奇格布拉克组中的葡萄状白云石及缝洞充填物的微区

\begin{matrix} δ^{13} C_{PDB} \end{matrix}

、

\begin{matrix} δ^{18} O_{PDB} \end{matrix}

变化（a— XH101-11-1; b— XH101-12-1; c— XH101-12-2; d— DEG-Z₂q-1; e— DEG-Z₂q-3; f— DEG-Z₂q-4）Fig.5 Data of

\begin{matrix} δ^{13} C_{PDB} \end{matrix}

\begin{matrix} δ^{18} O_{PDB} \end{matrix}

of micro-drill samplings of shell-comb or grape-like dolostone and minerals filled in pores or vugs and fractures and variation for botryoidal dolostone in Qigebulake Formation at Dong'ergou section and Well XH101, northern Tarim Basin

从东二沟及星火101井奇格布拉克组葡萄状白云岩及云质灰岩中的微区碳氧同位素变化(图 5)可见:

1)从皮壳状边缘或暗色不发光的核部(蓝细菌)至边缘, 两者的氧同位素均显示出强烈负漂移, 但基线值不同, 东二沟中 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ < -2.0‰ ; 而星火101井 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ > 1.0‰ , 前者受大气水改造更普遍;

2)星火101井葡萄状白云岩的 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 、 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 协同负漂移, 但东二沟葡萄状白云岩及云质灰岩中的 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 呈平缓起伏或变化较小; 且两者 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ “ 基线” 不一样, 前者在 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 为3‰ , 接近背景值; 而后者为2‰ 左右, 反映出后者经历了更强大气水改造作用;

3)葡萄状、皮壳状的水平纹层、明暗条带的粉晶云岩中的 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 波动一般均小于0.1‰ 、 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 波动一般小于0.2‰ ; 一般地, 若沉积时温差10, ℃(年均)所产生的大气水 δ ¹⁸O 可达到-4‰ ~-5‰ (Anderson and Arthur, 2009), 由此推断, 形成葡萄状或皮壳状结构的白云石及云质灰岩流体温度变化较小(< 0.5, ℃)。

表2 塔里木盆地北部东二沟及星火101井奇格布拉克组(Z₂q)不同成岩矿物的有序度及碳、氧、锶同位素值或变化范围 Table2 Data of sequentiality,

\begin{matrix} δ^{13} C_{PDB} \end{matrix}

\begin{matrix} δ^{18} O_{PDB} \end{matrix}

and ⁸⁷Sr/⁸⁶Sr for dolomites or calcites developed in different diagenetic stages in Qigebulake Formation at Dong'ergou section and Well XH101, northern Tarim Basin

不同类型岩相	样品数 (C、O/Sr)	有序度δ	$\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ /‰		$\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ /‰		⁸⁷Sr/⁸⁶Sr
			平均值	变化范围	平均值	变化范围	平均值	变化范围
D00	3/3		2.13	1.8~2.60	-5.87	-6.40~-5.40	0.70909	0.70887~0.70939
D01			2.50	2.29~2.51	-3.30	-3.08~-3.09
D010			1.9		-3.83
D011	6		1.72	0.80~2.57	-5.98	-6.79~-4.40
D40~D41	4/1		1.45	0.77~2.30	-7.52	-8.78~-6.28	0.70924
D5	9/5		0.16	-1.90~2.46	-9.97	-12.8~-7.50	0.70947	0.70888~0.71000
C7	2/1			-5.5~-1.90		-13.64~-12.80	0.70968
D00	6/3	0.69(0.63~0.73)	3.24	1.92~4.25	-2.6	-3.82~-1.56	0.70708	0.70293~0.70926
D01(葡萄状)	4/1	0.78(0.76~0.79)	2.9	2.50~3.07	0.19	-0.16~-0.52	0.70918
D2	2			1.04~1.90		-6.67~-5.60
D4	1		0.8		-7.2		0.70982
D5
D6	1/2		-0.8		-13.8		0.71840	0.71777~0.71909
C7	2			0.47~0.73		-9.91~-8.93

表2 塔里木盆地北部东二沟及星火101井奇格布拉克组(Z₂q)不同成岩矿物的有序度及碳、氧、锶同位素值或变化范围 Table2 Data of sequentiality,

\begin{matrix} δ^{13} C_{PDB} \end{matrix}

\begin{matrix} δ^{18} O_{PDB} \end{matrix}

and ⁸⁷Sr/⁸⁶Sr for dolomites or calcites developed in different diagenetic stages in Qigebulake Formation at Dong'ergou section and Well XH101, northern Tarim Basin

3.3 元素地球化学

一般认为, 海相碳酸盐岩中的Fe, Mn含量相对较低、而Sr、Sr/Ba、Na+K相对较高; Sr/Ba(> 1.0), 仅有深海与滞留浅海环境或非海相碳酸盐岩Sr/Ba< l; 同样, 海水成岩的方解石Sr以及Sr/Ba含量更接近于海水平均值; 而埋藏成岩的方解石或白云石中的Fe、Mn、Sr/Ba相对较高; 而在热水成因碳酸盐岩矿物则具有更高的Si, Sr、F, B、亲铜和亲铁元素等; 而较低的MgO、Fe₂O₃、Sr、Ba、Na+K等主要反映了碳酸盐岩的淡水淋滤作用(Nicholls, 1967; Cicero and Lohmann, 2001; 钱一雄等, 2009)。

对东二沟及星火101井奇格布拉克组葡萄状白云石及缝洞充填物常量元素分析(表 3); 泥粉晶云岩D00、皮壳状、葡萄状云岩及云质灰岩D01、粉细晶云岩D1及孔洞中的中粗晶白云石或含方解石或孔洞中的粗巨晶方解石的常量元素组成对比发现, 有以下现象:(1)Al₂O₃含量按D01< D00< D1、Fe₂O₃按D01< D00< D1、MnO按D01< D1< D00、Na₂O+K₂O之和D00< D01< D1、P₂O₅含量按D00< D1< D01依次增加; (2)无论是孔洞中的中粗晶白云石或含方解石或孔洞中的粗巨晶方解石中, 除MnO稍高于上述包括泥粉晶云岩、皮壳状、葡萄状云岩等基岩的对应值外, 其他常量元素含量均大大低于基岩。因此, 皮壳状、葡萄状白云岩中陆屑或残余孔隙流体中的不混溶组分Al₂O₃以及沉积环境的Fe₂O₃、MnO含量均低于基质泥粉晶云岩、但反映盐度Na₂O+K₂O、有机体的P₂O₅均高于基质泥粉晶云岩的对应值, 与细晶云岩以及孔洞中的中粗晶白云石等有显著的差别, 反映了它主要受海水沉积或早期海水成岩作用控制(表3和图6)。

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	图6 塔里木盆地北部东二沟及星火101井奇格布拉克组白云岩及缝洞充填物常量(a)微量元素(b)组成对比Fig.6 Various concentration of the major and trace element for different-type dolomites and minerals filled in pores or vugs and fractures in Qigebulake Formation at Dong'ergou section and Well XH101, northern Tarim Basin

表3 塔里木盆地北部东二沟及星火101井奇格布拉克组(Z₂q)基质、皮壳状、葡萄状白云岩及缝洞中不同充填物元素含量与比值 Table3 Geochemcal data and ratios of matrix, shell-comb or botryoidal dolostone and various minerals filled

in pores or vugs and fractures in Qigebulake Formation at Dong'ergou section and Well XH101, northern Tarim Basin

采样点	阿克苏东二沟								星火101井
样号	DEG-Z₂q -001	DEG-Z₂q -1-①	DEG-Z₂q -2-①	DEG-Z₂q -1-②	DEG-Z₂q -1-③	DEG-Z₂q -2-②	DEG-Z₂q-4	DEG-Z₂q -5-①	XH101-007-1 (5963.5, m)	XH101-002 (5973.97, m)
测试对象	泥粉晶云岩 D00	皮壳状粉晶云岩 D01	皮壳状含云质灰岩D01	细晶白云岩 D2	粗晶白云岩 D51	巨粗晶白云岩 D51	巨粗晶云灰岩 D51	粗巨晶方解石 C7	粉晶云岩 D00	粉细晶云岩 D1
Al₂O₃/%	0.08	0.05	0.05	0.45	0.04	0.02	0.02	0.03	0.07	0.09
Fe₂O₃/%	0.13	0.12	0.11	0.33	0.07	0.07	0.07	0.04	0.18	0.17
MgO/%	21.17	20.35	1.215	20.21	21.2	20.87	11.07	0.2274	22.161	21.6207
CaO/%	31.48	31.47	55.31	31.98	32.87	30.88	45.28	55.65	27.85	27.67
Na₂O/%	0.042	0.079	0.037	0.108	0.045	0.055	0.036	0.023	0.075	0.106
K₂O/%	0.059	0.046	0.033	0.189	0.032	0.032	0.030	0.030	0.013	0.017
MnO/μ g· g^-1	207.3	137.5	204.1	194.7	255.6	425.4	292.9	244.2	161.34	251.937
Zn/μ g· g^-1	2.90	1.34	0.60	2.66	1.19	3.61	1.60	2.03	0.06	0.09
Cu/μ g· g^-1	12.62	19.98	32.99	22.86	16.00	55.59	21.80	31.76	0.22	0.21
V/μ g· g^-1	0.13	0.12	0.17	0.19	0.33	0.12	0.14	0.09	21.31	17.26
Co/μ g· g^-1	0.83	0.79	9.62	0.94	0.77	0.82	0.79	0.97	7.26	5.76
Sr/μ g· g^-1	47.31	76.42	84.40	54.61	36.71	31.21	88.82	161.50	58.89	60.35
Ba/μ g· g^-1	4.97	6.39	5.96	9.48	3.89	69.12	3.44	94.34	17.58	11.69
Rb/μ g· g^-1	0.91	0.66	0.57	4.39	0.45	0.37	0.41	0.47	0.09	0.05
U/μ g· g^-1	2.07	1.36	0.08	0.11	0.09	0.26	0.13	0.27	0.49	1.06
Th/μ g· g^-1	60.76	30.10	15.51	174.40	7.40	12.69	8.08	9.62	0.02	0.01
P₂O₅/μ g· g^-1	37.05	221.10	4.06	5277	75.95	13.24	5.51	2.83	1.31	1.10
La/μ g· g^-1	4.23	0.64	2.24	1.42	0.43	1.07	0.75	1.54	0.28	0.43
Ce/μ g· g^-1	2.90	1.34	0.60	2.66	1.19	3.61	1.60	2.03	0.49	0.65
Pr/μ g· g^-1	1.07	0.19	0.46	0.80	0.48	1.36	0.90	0.62	0.07	0.09
Nd/μ g· g^-1	4.51	1.03	2.33	4.95	3.23	8.38	6.79	3.15	0.23	0.36
Sm/μ g· g^-1	0.86	0.28	0.66	1.37	0.86	1.88	2.04	1.08	0.04	0.08
Eu/μ g· g^-1	0.20	0.07	0.15	0.34	0.23	0.42	0.57	0.37	0.01	0.02
Gd/μ g· g^-1	0.79	0.30	0.63	1.36	0.63	1.48	1.80	1.42	0.05	0.07
Tb/μ g· g^-1	0.12	0.05	0.10	0.19	0.11	0.26	0.26	0.25	0.01	0.01
Dy/μ g· g^-1	0.66	0.38	0.64	1.06	0.62	1.60	1.42	1.55	0.06	0.09
Ho/μ g· g^-1	0.12	0.10	0.14	0.21	0.13	0.34	0.28	0.33	0.02	0.02
Er/μ g· g^-1	0.31	0.30	0.40	0.48	0.32	0.86	0.72	0.86	0.04	0.05
Tm/μ g· g^-1	0.04	0.05	0.06	0.06	0.05	0.13	0.10	0.13	0.01	0.01
Yb/μ g· g^-1	0.26	0.31	0.49	0.31	0.29	0.78	0.61	0.79	0.05	0.06
Lu/μ g· g^-1	0.04	0.05	0.07	0.04	0.05	0.11	0.09	0.11	0.01	0.01
Y/μ g· g^-1	4.83	5.11	6.77	10.27	4.66	13.14	12.71	15.25	0.61	0.75
􀰐REE/μ g· g^-1	20.94	10.21	15.75	25.52	13.26	35.39	30.63	29.50	1.96	2.70
Mg/Ca	0.8006	0.7698	0.0262	0.7523	0.7678	0.8046	0.2910	0.0049	0.9473	0.9302
Sr/Ba	9.53	11.96	14.16	5.76	9.43	0.45	25.80	1.71	3.35	5.16
Sr/Mn	0.23	0.56	0.41	0.28	0.14	0.07	0.30	0.66	0.36	0.24
Fe/Mn	6.36	8.44	5.20	16.88	2.59	1.62	2.51	1.60	11.15	6.66
L/H	1.92	0.53	0.69	0.82	0.94	0.89	0.70	0.43	1.32	1.54
δ Eu	0.71	0.74	0.71	0.76	0.91	0.75	0.90	0.92	0.86	0.72
δ Ce	0.30	0.76	0.12	0.44	0.37	0.43	0.24	0.43	0.83	0.71
Y/Ho	39.09	53.76	49.56	48.70	36.74	39.14	44.70	45.74	37.59	37.90

注: δ Eu=(Eu_样品/0.087)/{[(Sm_样品/0.231)+(Gd_样品/0.306)]/2}; δ Ce=3× (Ce_样品/66.7)/[2× (La_样品/31.1)+(Nd_样品/27.4)]。

类似地, 主要的微量元素或元素比值对比发现, 有以下现象:(1)V含量按D00< D01< D1、Ba按D00< D01< D1、Sr按D00< D1< D01、Sr/Ba 按D1< D00< D01、Sr/Mn按D00< D1< D01、Fe/Mn按D00< D01< D1依次增加; (2)无论是孔洞中的中粗晶白云石或含方解石或孔洞中的粗巨晶方解石中的V含量均低于基岩对应值, 而Ba含量均高于基岩对应值, 溶洞中的方解石的Sr、Sr/Mn高于基岩对应值或比值; 但Sr/Ba、Fe/Mn值相对较低或最低; 而溶洞中的白云石的Sr、Sr/Mn、 Fe/Mn、均低于基岩对应值或比值。

因此, 皮壳状、葡萄状白云岩中Sr、Sr/Ba、Sr/Mn以及低温时活跃的Hg、Cu金属的含量或比值较高, 反映了它受海源流体的影响较为明显, 而随着白云石(结构)化程度的提高, 总体呈现出Sr/Ba、Fe/Mn等减小, Cu略有增加、Hg急剧下降(表3和图6)。

稀土元素分析及分配模式(表 3, 图7)研究表明: (1)泥粉晶云岩D00: 稀土总量为20.94, μ g/g, LREE/HREE 为1.92, δ Eu为0.71(0.75~1.06), δ Ce为0.30; 总体为轻重稀土分异不明显、负铈异常明显; (2)粉晶云岩D1(星火1井): 稀土总量为1.96~2.70, μ g/g, LREE/HREE=1.32~1.54、δ Eu=0.72~0.86、δ Ce=0.71~0.84, 为总量最低、与澳大利亚太古代后页岩(PAAS)(Mcl ennan, 1989)“ 帽型” 配分模式相似; 细晶云岩D₂(东二沟)稀土总量25.52, μ g/g, LREE/HREE为0.82, δ Eu为0.76, δ Ce为0.44, 为重稀土富集、负铈异常; (3)皮壳状、葡萄状白云岩及云质灰岩中的D01: 稀土平均总量为12.98, μ g/g, 分布范围10.21~15.75, μ g/g、LREE/HREE平均为0.61(0.53~0.69), δ Eu平均为0.73(0.71~0.74); δ Ce平均为0.44(0.12~0.76); 为重稀土富集、分别呈高(灰云质)和中等的负铈异常(云质); 强烈负铈异常指示了相对还原环境; (4)孔洞中中粗晶白云石及一个含云的方解石D51: 平均稀土总量为26.43, μ g/g, 分布范围13.26~35.39, μ g/g, LREE/HREE平均为0.85(0.70~0.94), δ Eu平均为0.85(0.75~0.91); δ Ce平均为0.35(0.24~0.43), 与D2相类似, 推断是D2经历了重结晶作用形成; (5)孔洞中的粗巨晶方解石C7: 稀土总量为29.50, μ g/g, LREE/HREE为0.43, δ Eu平均为0.92; δ Ce为0.43。

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	图7 塔里木盆地北部东二沟及星火101井中奇格布拉克组不同类型白云岩及缝洞充填物稀土配分模式Fig.7 The distribution pattern of rare earth elements of different-type dolomites and minerals filled in pores or vugs and fractures in Qigebulake Formation at Dong'ergou section and Well XH101, northern Tarim Basin

综上所述, 皮壳状、葡萄状白云岩及云质灰岩中的稀土总量介于基质与粉细晶云岩之间, 其LREE/HREE相对较低, δ Eu与基岩相似, δ Ce相对较低, 比泥粉晶白云岩对应值高, 但与粉细晶值相似; 总体呈现出海源流体的特征。

4 讨论与结论

1)在上震旦统的奇格布拉克组顶部白云岩中, 皮壳状、葡萄状白云石有以下3种不同矿物序列: (1)栉壳状— 皮壳状、马牙状的2~3层的明、暗的纤状粉细晶白云石; (2)呈纹层条带的灰白— 白色纤状— 放射状及粒状粉细晶白云石; (3)皮壳状、肾状和葡萄状粉细晶白云石; 其中, 纤状或放射状矿物形态指示了原可能为文石;

2)藻云岩基质与皮壳状、葡萄石状白云石残留了数量较多的球形、杆形、孢子形等蓝细菌, 包绕颗粒生长呈团块状的“ 葡萄状” 或泡沫状结构; 阴极发光有3种: (1)泥粉晶云岩, 发暗色橙红色光; (2)层纹— 条带状的纤状、皮壳状、葡萄石白云石发明暗或环带状橙红色光; (3)细晶白云石, 发中等橙红色光; 中细晶白云石或中粗晶方解石, 较暗或不发光;

3)皮壳状、葡萄石状白云石的暗色(蓝细菌)边缘至核部或中心微区碳氧同位素变化表明, 环带内 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 、 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 变化较小、环带外强烈负漂移; 东二沟与星火101井的变化的 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 、 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ “ 基线” 不一样, 前者 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ =2‰ 、 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ < -2.0‰ ; 后者中 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ =3‰ (接近背景值)、 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ > 1.0‰ , 前者的晶体颗粒相对较粗, 其 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 、 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 比后者的负偏明显, 反映了其经历的大气水影响作用较强;

4)与基质白云石相比, 葡萄状、皮壳状白云石 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 变化相似; 但 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 正偏明显, ⁸⁷Sr/⁸⁶Sr 比基岩平均值稍高(70887~0.70939)、但与震旦纪海水(0.7087~0.7094)相似, 反映了海水特征; 但随着云化程度的增加, $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 、 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 负偏明显, ⁸⁷Sr/⁸⁶Sr 值逐渐增加; 反映了后期大气水、壳源或其他成岩流体介入于水— 岩反应过程;

5)皮壳状、葡萄石状白云石的韵律纹层或条带内的 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 波动一般小于0.1‰ 、 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 波动小于0.2‰ ; 由此推断, 形成葡萄状或皮壳状结构的白云石的流体温度变化较小(< 0.5, ℃)、其主生长期在应为稳定的“ 沉积或成岩” 环境, 成岩后期有大气淡水参与, 导致过渡带或边缘 $\begin{matrix} δ^{13} C_{PDB} \end{matrix}$ 和 $\begin{matrix} δ^{18} O_{PDB} \end{matrix}$ 稍负偏现象, 这从明暗条带状或暗色至不发光的阴极特征也可得到佐证;

6)皮壳状、葡萄状白云岩Al₂O₃ 、Fe₂O₃ 、MnO含量均低于基质泥粉晶云岩对应值、但反映盐度Na₂O+K₂O、有机体的P₂O₅或指示海相或海水深度的Sr、Sr/Ba、Sr/Mn值以及低温时活跃的Hg、Cu金属的含量或比值均高于基质泥粉晶云岩的对应值; 反映了受海水影响较为明显; 且随着白云石(结构)化程度的提高, 总体呈现出MnO含量增加; Al₂O₃ 、Fe₂O₃、Na₂O+K₂O、P₂O₅、Sr/Ba、Fe/Mn等值递减;

7)皮壳状、葡萄状白云岩或云质灰岩中的稀土总量介于基质泥粉晶云岩与粉细晶云岩之间, LREE/HREE相对较低, 强烈负铈异常、δ Ce相对较低; 重稀土富集及Y/HO; δ Eu与基岩相似, 上述的轻稀土亏损常指示未经充分分异、保存的海水(Garrison et al., 2013)δ Ce相对较低, 比泥粉晶白云岩对应值高, 但与粉细晶值相似; 而δ Ce相对较低, 比泥粉晶白云岩对应值高, 一般指示了弱还原的沉积环境, 但负铈异常有多种原因, 如硅质陆屑、铁氧化物、含磷等影响(Garrison et al., 2013; Susanne et al., 2013)δ Eu弱负异常, 未指示热液流体的影响(亏损的LREE、正δ Eu及Y异常), 反映出主要形成于弱还原下保存较好的海水条件中(Maree Corkeron et al., 2012)。

综上所述, 皮壳状、葡萄状白云石形成于稳定的温度条件、弱还原条件海水中、或在成岩早期或浅埋藏残余孔隙(海水)中, 推断在间冰期, 大量营养物注入海洋, 促进了光合作用以及大气的氧化过程(Hardie, 2003; Hood et al., 2011; Grant, 2013)。但东二沟皮壳状、葡萄状白云石还经历了与构造抬升有关的大气水作用的强烈的叠加改造。

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14	张杰, Brian Jones, 潘立银, 周进高, 秦玉娟, 郝毅, 武明德. 2014. 四川盆地震旦系灯影组葡萄状白云岩成因. 古地理学报, 16(5): 715-725. [Zhang J, Brian J, Pan L Y, Zhou J G, Qin Y J, Hao Y, Wu M D. 2014. Origin of botryoidal dolostone of the Sinian Dengying Formation in Sichuan Basin. Journal of Palaeogeography(Chinese Edition), 16(5): 715-725] [文内引用:1]
15	张师本, 倪寓南, 龚福华, 卢辉楠, 黄智斌, 林焕令. 2003. 塔里木盆地周缘地层考察指南. 北京: 石油工业出版社, 1-280. [Zhang S B, Ni Y N, Gong F H, Lu H N, Huang Z B, Lin H L. 2003. A Guide to the Stratigraphic Investigation on the Periphery of the Tarim Basin. Beijing: Petroleum Industry Press, 1-280] [文内引用:1]
16	张荫本. 1980. 震旦纪白云岩中的葡萄状构造成因初探. 石油实验地质, (4): 40-43. [Zhang Y B. 1980. Preliminary study on the botryoidal structures in the Sinian dolostones. Petroleum Geology & Experiment, (4): 40-43] [文内引用:1]
17	Anderson T F, Arthur M A. 2009. Stable isotopes of oxygen and carbon and their application to sedimentologic and paleoenvironmental problems. In Stable Isotopes in sedimentary Geology(Columbia, SC: SEPM Short Course), 10: 1-151. [文内引用:1]
18	Cicero A D, Lohmann K C. 2001. Sr/Mg variation during rock-water interaction: Implications for secular changes in the elemental chemistry of ancient seawater. Geochimica et Cosmochimica Acta, 65(5): 741-761. [文内引用:1]
19	Flügel E. 2004. Microfacies of Carbonate Rocks: Analysis, Interpretation and Application. Berlin: Springer-Verlag: 369-396. [文内引用:1]
20	Garrison R L, Lee R, Kump, Michael A Arthur. 2013. Shallow water redox conditions from the Permian-Triassic boundary microbialite: The rare earth element and iodine geochemistry of carbonates from Turkey and South China. Chemical Geology, 351: 195-208. [文内引用:2]
21	Gerdes G. 2007. Structures left by modern microbial mats in their host sediments. In: Schieber J, Bose P K, Eriksson P G, et al. (eds). Atlas of Microbial Mat Features Preserved within the Siliciclastic rock record. Amsterdam: Elsevier, 5-38. [文内引用:1]
22	Gerdes G. 2010. What are microbial mats? In: Seckbach J, Oren A(eds). Microbial Mats: Modern and Ancient Microorganisms in Stratified Systems Cellular Origin, Life in Extreme Habitats and Astrobiology, 14. Berlin: Springer-Verlag, 5-25. [文内引用:1]
23	Grant M Young. 2013. Precambrian supercontinents, glaciations, atmospheric oxygenation, metazoan evolution and an impact that may have changed the second half of Earth history. Geoscience Frontiers, 4(3): 247-261. [文内引用:1]
24	Halverson G P, Dud S F, Maloof A C, Bowring S A. 2007. Evolution of the ⁸⁷Sr/⁸⁶Sr composition of Neoproterozoic seawater. Palaeongeography, Palaeoclimatology, Palaeoecology, 256(3-4): 103-129. [文内引用:1]
25	Hardie L A. 2003. Secular variations in Precambrian seawater chemistry and the timing of Precambrian aragonite seas and calcite seas. Geology, 31: 785-788. [文内引用:1]
26	Hood A S, Wallace M W, Drysdale R N. 2011. Neoproterozoic aragonite-dolomite seas?Widespread marine dolomite precipitation in Cryogenian reef complexes. Geology, 39(9): 871-874. [文内引用:1]
27	Maree Corkeron, Gregory E Webb, Joshua Moulds, Kathleen Gre. 2012. Discriminating stromatolite formation modes using rare earth element geochemistry: Trapping and binding versus in situ precipitation of stromatolites from the Neoproterozoic Bitter Springs Formation, Northern Territory, Australia. Precambrian Research, 212-213: 194-206. [文内引用:1]
28	McCrea J M. 1950. On the isotopic chemistry of carbonates and a paleotemperature scale. The Journal of Chemical Physics, 18. 6(1950): 849-857. [文内引用:1]
29	Nicholls. 1967. Trace elements in sediments: An assessment of their possible Utility as depth indicators. Marine Geology, 5: 439-555. [文内引用:1]
30	Susanne Göb, Anselm Loges, Nils Nolde, Michael Bau, Dorrit E. Jacob, Gregor Markl. 2013. Major and trace element compositions(including REE)of mineral, thermal, mine and surface waters in SW Germany and implications for water-rock interaction. Applied Geochemistry, 33: 127-152. [文内引用:1]

2002

0.0

陈明, 许效松, 万方, 尹福光. 2002. 上扬子台地晚震旦世灯影组中葡萄状雪花状白云岩的成因意义. 矿物岩石, 22(4): 33-37.

[Chen

, Xu X

, Wan

, Yin F

. 2002. Gensis and significance of grape and show flake-shaped dolomite from Dengying Formation of Upper Sinian in Upper Yangtze platform region. Journal of Mineral Petrology, 22(4): 33-37]

葡萄状-雪花状白云岩是白云岩形成之后经淡水淋滤作用而成,葡萄内或雪花周围的有机物质不是原生藻,而是蓝绿藻经细菌腐解后形成的细茵集合体.该套白云岩的形成与沉积环境关系密切,与藻类多少无关.葡萄状白云岩富含有机物质,而雪花状白云岩孔洞发育,因此葡萄状-雪花状白云岩既是生油层,又是良好的储集层,对其重新认识和定位,必将为寻找深部油气资源提供极为重要场所.

... 陈明等,2002 ...

2003

0.0

方少仙, 侯方浩, 董兆雄. 2003. 上震旦统灯影组中非叠层石生态系兰细菌白云岩. 沉积学报, 21(1): 96-105.

[Fang S

, Hou F

, Dong Z

. 2003. Non-stromatoltite ecologic system cyanobacteria dolostone in Dengying Formation of Upper Sinian. Acta Sedimentologica Sinica, 21(1): 96-105]

Dengying formations 2 and 3 members of upper-Sinian is one of major nature gas reservior in Sichuang basin. In light colour dolostone abound with carbonification blackly non-stromatolite ecologic system cyanobacteria dolostone. It's developed not also in depositional and cementational stage,but also in hypergene diagenetic stage.At the depositional stage, it occure in laminae or surounded the grain growth in all sides.The singel bed thickness of these cyanobacteria dolostones from 1 mm to over 10 cm. And total thickness occupy about 10 percent in 2 and 3 members of Denging formation. Sometimes it show up incontinual small blackly points developed in whitely stromatolite ecologic system cyanobacteria dolostones,suck as stromatalolates, oncolite and others.At the hypergene diagenetic stage,the blackly non-stromatolite ecologic system cyanobactria mainly occurred in many generations linely laminae interbeded with wihite coloure fiber texture dolostone laminae filling the karstic cavity and channel, even in enlargeie dissolived crack.The major sharps of non-stromatolite ecalogic system cyanobactria are sphere,ellipsod and cudgel,occasionally are mushroom,monkhat and others.The colongs presented sharp are string bead,grass cluster,croteh and like the valcanic eruption,etc. All of these sharps show palaeocology of upword groweh or toword the centre of karstic cavity and channel. Degradation in test of modern cyanobactria evidenced that non-stromatolite ecologic system cyanobacteria dolostones is one of hydrocarbon source rock in Dengying formation.

上震旦统灯影组 2段和 3段是四川盆地主要天然气储层之一。在浅色白云岩地层中富含炭化的黑色非叠层石生态系兰细菌白云岩。它既可发育于沉积期和胶结作用期 ,也可发育于表生成岩作用期。沉积期发育的非叠层石生态系兰细菌白云岩呈纹层状产出或围绕颗粒的四周生长。这类兰细菌白云岩的单层厚度从 1mm到 >10 cm不等 ,其总厚度约占灯影组 2段和 3段的 1/ 10左右 ,有时也呈不连续的黑色小点发育于白色叠层石生态系兰细菌白云岩的叠层石、层纹石中。胶结作用期 ,二或三个世代亮晶胶结物交替发育“充填”孔隙。表生成岩作用期 ,黑色的兰细菌主要呈多世代的线状纹层与白色纤维状白云石组成多世代的间互纹层充填在岩溶溶洞、溶沟以及扩溶的裂隙中。非叠层石生态系兰细菌主要形态有球形、椭球形和棒形 ,偶有蘑菇形及其它形状。群体呈现为串珠状、草丛状、分叉树枝状和类似于火山喷发状等等。群体的古生态表现为向上生长、围绕颗粒向四周发散生长、粘结颗粒 ,或向原生粒间孔隙、次生溶洞、溶沟中心向心生长。对现代兰细菌的降解实验佐证所讨论的非叠层石生态系兰细菌是灯影组中烃源岩之一。

... 方少仙等,2003 ...

... 施泽进等,2011),(3)多种成岩下产物(方少仙等,2003 ...

1985

0.0

2015

0.0

... 郝毅等,2015 ...

1991

0.0

刘怀仁, 刘明星, 胡登新, 付强. 1991. 川西南上震旦统灯影组沉积期的暴露标志及其意义. 沉积与特提斯地质, 11(5): 1-10.

[Liu H

, Liu M

, Hu D

, Fu

. 1991. The exposure indicators formed during the deposition of the Upper Sinian Dengying Formation in southwestern Sichuan and their significance. Sedimentary Geology and Tethyan Geology, 11(5): 1-10]

正对川西南乃至整个扬子区上震旦统灯影组的研究已有约70年的历史。以往的研究成果大致可归结为:(1)根据地层的岩石及生物特征将灯影组划分为:一段(下贫藻段)、二段(富藻层和上贫藻层)、三段、顶段(麦地坪段),其中一、二、三段的年代为晚震旦世,顶段为早寒武世;(2)从沉积学研究的角度出发,认为灯影组为潮坪环境的碳酸盐台地沉积;(3)通过生物地层学的研究,确定了大量的藻类、微古植物、小壳生物门类及其属种,以及与生物生存活动有关的生物遗迹化石。以往的研究成果无疑对我们分析、认识灯影组

... 牟传龙等,2015),(2)大气水潜流带成因(刘怀仁等,1991 ...

2013

0.0

罗平, 王石, 李朋威, 宋金民, 金廷福, 王果谦, 杨式升. 2013. 微生物碳酸盐岩油气储集层研究现状与展望. 沉积学报, 31(5): 807-823.

[Luo

, Wang

, Li P

, Song J

, Jin T

, Wang G

, Yang S

. 2013. Review and prospectives of microbial carbonate reservoirs. Acta Sedimentologica Sinica, 31(5): 807-823]

Microbial carbonates are important oil & gas reservoir rocks, as well as the main rock types in China old strata. Microbial carbonates can be divided into stromatolites, thrombolite，dendrolite and other two types. The reservoir pore systems are closely related to microbialite sedimentary process, and mostly affected by structures and textures of microbialites. Framework and fenestral vugs are the main types of reservoir space. From Middle-Neo Proterozoic to Mesozoic, microbial carbonates reservoirs are discovered globally in various oil & gas fields, so that their petroleum resource potential is great.The researches on rock types,litofacies texture, depositional models and favorable facies zones of microbial reservoir, are well worth deep study in future.

微生物碳酸盐岩是一种重要的油气储集岩。在中国古老深埋碳酸盐岩地层中它们是主要的岩石类型。微生物碳酸盐岩通常可划分为叠层石、凝块石、树枝石、均一石和核形石等五种类型。储层孔隙系统与微生物岩的沉积结构和构造密切相关，窗格孔（洞）和格架孔（洞）是主要储集空间类型。全球中新元古界至中生界都发现了以微生物碳酸盐岩为储层的油气田，资源潜力巨大。微生物岩储层的岩石类型、沉积构造、相序结构、沉积模式和储层有利相带尚有许多不明晰之处，是今后进一步深化研究的重点方向。

... 罗平等,2013),至今未曾见有关葡萄状白云岩的报道 ...

2015

0.0

牟传龙, 王秀平, 梁薇, 王远翀, 门欣. 2015. 上扬子区灯影组白云岩葡萄体特征及成因初探: 以南江杨坝地区灯影组一段为例. 沉积学报, 33(6): 1097-1110.

[Mou C

, Wang X

, Liang

, Wang Y

, Men

. 2015. Characteristics and genesis of grape-like stone of dolomite in Sinian Dengying Formation in Yangtze region: A case from the first section Dengying formation in Yangba, Nanjiang, Sichuan Province. Acta Sedimentologica Sinica, 33(6): 1097-1110]

There is a special and extensively developed type of dolomite in Dengying Formation and its corresponding formations of Upper Sinian in Yangtze region, which is with an odd-looking like renal globule, ellipsoid, grape-like body and sphere in irregular shape(hereinafter referred to as the "grapes"). Many scholars in China believed that this kind of dolomite was affected by atmospheric fresh water during formation. "Grapes" are like pieces of tufa on the macro, distributed along interfaces of rock strata and fractures. On the basis of the detailed observation and description of outcrops, and using polarized light microscope, cathodoluminescence and scanning electron microscopy(SEM), the characteristics and genesis of grape-like dolomite in the First section of Sinian Dengying Formation in Yangba Town of Nanjiang County, were studied. The results show that the grapes were as the fillings in surrounding rocks through diagenetic ways into rocks. The grapes are usually like hemispheroids with cores and alternated dark and bright shells, and composed mostly of dolomite and a little of authigenic quartz. The cores and dark shells were formed from biological and chemical processes in sea water, according to the algal binding aggregates with irregular microbial filaments, high carbon elements in the mineral components, and in combination with the existence of the seabed hard ground. The bright shells were composed by fiber cements, which in the same thickness and formed the outer layers of grapes. Grapes are with polyhedral intersection and filled with fiber cements in the residual space, so the outer of grapes are forming in marine phreatic water and mainly due to cementation. Cores were the irregular bumps on the wall of dissolution holes and seams, the characteristics of grapes were closely related to the size and shape of bumps and the features of growth space. The fixed point and regular structure indicate that grapes were formed in stable water. Aragonite or high-magnesian calcite was the original component, because of the dolomitization, the grape-like dolomite was formed and with crystalline-granular texture. The characteristics cathode luminescence of grapes are similar to surrounding rocks, and according to the occurrence and the morphological characteristics of the grapes, the hemispheroids with cores and alternated dark and bright shells are identified as an sedimentary structure and named grape-like structure. The sedimentary structure is a deposition-diagenetic structure and due to biological and chemical effect, and formed in the stable sea environment.

... 牟传龙等,2015),(2)大气水潜流带成因(刘怀仁等,1991 ...

2009

0.0

钱一雄, 陈强路, 陈跃, 罗月明. 2009. 碳酸盐岩中缝洞方解石成岩环境的矿物地球化学判识: 以塔河油田的沙79井和沙85井为例. 沉积学报, 27(6): 1027-1032.

[Qian Y

, Chen Q

, Chen

, Luo Y

. 2009. Mineralogical and geochemical identification for diagenetic settings of paleo-caves and fractures-filling & vugs calcites in carbonate: Taking wells S79 and S85 for example. Acta Sedimentologica Sinica, 27(6): 1027-1032]

摘　要：在塔里木盆地塔河油田4区沙79井、6区沙85井奥陶系鹰山组岩芯的详细观察基础上，对裂隙、溶洞及巨型洞穴中的方解石晶体的晶胞参数、化学成分、碳、氧同位素、流体包裹体中的氢同位索等分析与研究表明，至少存在两种成岩环境：一是以大气淡水表生环境，方解石中晶胞参数（c）=17.057－17.062А，Fe2O3=0.06％－0.07％，Sr=53.3×10^- 6－96.2×10^-6、Ba=19×10^-6－28×10^-6，Mg/Ca（×10^- 3）=1.94－5.14，Sr／Ba=2.12－5.24，δ18 OPDB较低（-15‰－-17‰）、较低δ18 CPDB（-4‰－-2.0‰），不含或较少含烃类，流体包裹体中氢δDPDB=-94.99‰－-109.54‰为特征；另一是地层混合水埋藏环境为主，方解石中晶胞参数（c）=17.064－17.065А（个别达17.212А）、Fe2O3=0.06％－0.18％，Sr=111×10^- 6－208×10^-6、Ba=215×10^-6－479×10^- 6，Mg／Ca（×10^3）=1.53－1.76，Sr／Ba=0.49－0.58，方解石δ18 OPDB低（-9.6‰－-13.7‰）、流体包裹体中氢δDPDB=-77.5‰－-88.2‰为特征；另外，在巨型洞穴中方解石中组分的剧烈变化反映了洞穴充填发生于不同的水文地质-地球化学体系。

... 钱一雄等,2009) ...

2014

0.0

钱一雄, 杜永明, 陈代钊, 尤东华, 张军涛, 陈跃, 刘忠宝. 2014. 塔里木盆地肖尔布拉克上震旦统奇格布拉克组剖面层序界面与沉积相分析. 石油实验地质, 36(1): 1-8.

[Qian Y

, Du Y

, Chen D

, You D

, Zhang J

, Chen

, Liu Z

. 2014. The stratigraphic sequences and sedimentation analysis of Qigebulak Fm of the upper Sinian at Xianerbulak of Aksu in Tarim Basin. Petroleum Geology & Experiment, 36(1): 1-8]

Sinian is one of the most important stages of the development of passive continental margin basin in the Tarim Basin. Based on the measurement and analysis of profiles of the Qigebulak Formation (Z 2 g ) of the upper Sinian at Xianerbulak of Aksu, it has been concluded that the Ⅲ-order sequence boundary surfaces with hiatus and lithofacies transition and the Ⅱ-order surfaces with transgressive onlap and sequence unconformity interface develop at the bottom and on the top of the Qigebulak Formation, respectively. In the middle of the formation, deepening interruption surface and shallowing-upward Ⅳ-Ⅴ sequences develop. The Milankovitch cycle of carbonate rocks has been found, under either peritidal (becoming shallow, fine-grained and thin upwards) or subtidal (becoming shallow, coarse-grained and thick upwards) environments controlled by sea level changes. Stromatolites are widespread, mainly consisting of various microbial mats. The Qigebulak Formation can be divided into 3 lithologic sections from bottom to top, among which the lower section changes from supratidal to intertidal, the lower part of intertidal to intertidal, and intertidal to supratidal; the middle section is characterized by the frequent variation from the lower part of intertidal to subtidal and the stable environment of subtidal. Carbon isotopes are strongly positive at the bottom, stable in the middle and upper sections, and weakly positive at the top. Sea levels change frequently at the bottom, and stably decrease in the middle and upper sections.

1. Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China; 2. Engineering Supervision Center, SINOPEC Northwest Oilfield Company, Urumqi, Xinjiang 830011, China; 3. Research Institute of Geology and Geophysics, CAS, Beijing 100029, China; 4. SINOPEC Exploration & Production Research Institute, Beijing 100083, China

震旦纪是塔里木盆地被动大陆边缘盆地重要的发育期。通过对阿克苏肖尔布拉克剖面上震旦统奇格布拉克组的实测及综合分析认为：奇格布拉克组的底、顶部分别发育Ⅲ级沉积间断的岩相转换面和Ⅱ级海侵上超层序不整合界面；内部发育加深间断面、向上变浅的Ⅳ至Ⅴ级层序界面，发育了受海平面变化控制的环潮型（向上变浅、变细、变薄）至潮下型（向上变浅、变粗、变厚）的碳酸盐岩米级旋回，叠层石相对发育，可能由多种形态的微生物席构成。奇格布拉克组可划分为下、中、上3个岩性段：其中，下亚段为潮上至潮间、潮间下部至潮间、潮间至潮上的振荡变化，中段为潮间下部至潮下带的频繁、振荡变化至潮下稳定的沉积环境；对应的碳同位素呈底部较强烈正偏，中上部较为稳定，且上部稍弱正偏的特征；海平面具有下部频繁变动、中上部稳定下降的变化趋势。

... 能量相对高的潮间至潮上带的浅水环境(钱一雄等,2014) ...

2011

0.0

施泽进, 梁平, 王勇, 胡修权, 田亚铭, 王长城. 2011. 川东南地区灯影组葡萄石地球化学特征及成因分析. 岩石学报, 27(8): 2263-2271.

[Shi Z

, Liang

, Wang

, Hu X

, Tian Y

, Wang C

. 2011. Geochemical characteristics and genesis of grapestone in Sinian Dengying Formation in south-eastern Sichuan basin. Acta Petrologica Sinica, 27(8): 2263-2271]

For a long time, there is a dispute about the genesis of the grapestone in Dengying Formation. The geochemical characteristics of grapestone and basement rock are analyzed and compared in detail and the genetic environments of the grapestone are discussed in this article. Compared with basement rock, there are relatively obvious Ce negative anomaly and relatively low total content of rare-earth elements in the grapestone, which indicates that the grapestone and basement rock were not deposited simultaneously. There are low content of Na, K, high content of Mn, Fe, low content of Sr/Ba ratio, high content of (87)Sr/(87)Sr ratio and both carbon and oxygen isotope negative anomaly, which illustrates that the grapestone was formed under fresh water. It can be corroborated that there was a brief exposure during the deposition of Dengying Formation which made Dengying Formation expose to earth's face, leached by meteoric water and emerge small-scale karst to create the conditions for the genesis of the grapestone. The brief exposure has very important significance for a better understanding of the genesis of the grapestone and the development of the reservoirs in the middle of Denying Formation.

长期以来,人们对灯影组葡萄石的成因存在较大的争议。本文对灯影组葡萄石及基岩的地球化学特征进行了详细的对比分析,讨论了灯影组葡萄石的形成环境。灯影组葡萄石与基岩相比,具有较明显的Ce负异常和相对低的稀土总含量,说明了葡萄石并非是和基岩同时沉积而成;葡萄石中Na、K元素含量低而Mn、 Fe含量较高,具有很低的Sr/Ba比值,同时具有碳、氧同位素明显偏负和 87 Sr/ 86 Sr值偏高的特点,表明葡萄石是在淡水的作用下形成的。证实了灯影组在沉积过程中有过一次短暂暴露过程,这次沉积间断使灯影组暴露地表接受淡水淋滤,形成了小规模的岩溶现象,为葡萄石的形成创造了条件。这次短暂暴露过程对人们更好地理解葡萄石的成因及灯影组中部储层的形成有重要的意义。

... 施泽进等,2011),(3)多种成岩下产物(方少仙等,2003 ...

2012

0.0

... 宋金民等,2012 ...

2010

0.0

王小林, 胡文瑄, 陈琪, 李庆, 朱井泉, 张军涛. 2010. 塔里木盆地柯坪地区上震旦统藻白云岩特征及其成因机理. 地质学报, 84(10): 1479-1494.

[Wang X

, Hu W

, Chen

, Li

, Zhu J

, Zhang J

. 2010. Characteristics and formation mechanism of Upper Sinian Algal Dolomite at the Kalpin Area, Tarim Basin, NW China. Acta Geologica Sinica, 84(10): 1479-1494]

This paper reported the petrology, geochemistry and possible origin of the upper Qigebulake Formation (Upper Sinian) algal dolomite at Kalpin Area, Tarim Basin. Petrologically, matrix dolomite (MD), bladed cement dolomite (BCD), and rhombic cement dolomite (RCD) are recognized under polarizing microscope examination. MDs were euhedral micrite dolomites with crystal size ranges from 2－5 μm; microbe associated spheroidal and sheet-like dolomites are common. They lack any evidence of precursor minerals. BCDs are composed of a series of euhedral ultralmicro-dolomites, which parallel the c axis. The length of BCDs varies from tens of μm to 100 um. RCDs occur in the center of the pores with a crystal size less than 50 μm. Geochemically, MDs have the highest Na2O content (average 380 ppm), moderate FeO, MnO content (average 727 ppm and 175 ppm, respectively). BCDs have moderate Na2O content and lowest FeO content (average 290ppm and 200 ppm respectively); the MnO content is below the detection limits. RCDs have the lowest Na2O content (average 200 ppm) and highest FeO, MnO content (average 750 ppm and 550 ppm, respectively). The 13C values (2.1－3.0 ‰, PDB) are in agreement with the reported results; the δ18O values are relatively higher than those reported values of Paleozoic carbonates, which implies Sinian seawater is relatively rich in 18O. It is interpreted that the MDs are microbially mediated primary precipitates and do not develop by dolomitization of precursor carbonates. RCDs origin from the volume-per-volume dolomitization of aragonite cement by the mixing water of meteoric water and seawater; while RCDs form under burial environment.

本文报道了塔里木盆地柯坪地区上震旦统奇格布拉克组藻白云岩岩石学与地球化学特征，并对其形成机理进行了探讨。从岩石学特征上看，藻白云岩可分为基质白云石、刃状白云石胶结物与菱形白云石胶结物。基质白云石为微晶自形白云石，晶体大小在2~5 μm之间，未见任何灰质前驱物，发育球形与片状白云石；刃状白云石胶结物垂直藻颗粒边缘向孔隙中心生长，长度在几十到100 μm之间，由一系列超微晶自形白云石沿c轴平行堆积而成；菱形白云石胶结物分布在孔隙中心，一般小于50 μm。从地球化学特征上看，基质白云石具有最高的Na2O含量（380 ppm）, FeO，MnO含量中等（727 ppm; 175 ppm）；刃状白云石胶结物Na2O含量中等(290 ppm)，FeO含量最低（200 ppm），MnO含量低于检测限；菱形白云石胶结物具有最低的Na2O含量(200 ppm)，最高的FeO，MnO含量(750 ppm, 550 ppm)。样品碳同位素组成与前人报道结果一致（2.1~3.0 ‰; PDB），氧同位素组成较古生代碳酸盐岩高（28.1~31.9 ‰; SMOW），说明震旦纪海水具有较高的δ18O值。本文认为基质白云石为微生物调制作用下原生沉淀的结果；刃状白云石形成于准同生环境下大气水-海水混合流体等体积交代文石胶结物的过程；而菱形白云石胶结物则形成于埋藏环境。

... 上震旦统发育的藻白云岩或微生物岩已有研究报道(王小林等,2010 ...

1998

0.0

向芳, 陈洪德, 张锦泉. 1998. 资阳地区震旦系充填白云石与古岩溶. 成都理工学院学报, 25(3): 436-441.

[Xiang

, Chen H

, Zhang J

. 1998. Filling dolomites and paleokarst of Sinian in Ziyang area. Journal of Chengdu Universtiy of Technology, 25(3): 436-441]

摘　要：

... 向芳等,1998 ...

2014

0.0

张杰, Brian

Jones

, 潘立银, 周进高, 秦玉娟, 郝毅, 武明德. 2014. 四川盆地震旦系灯影组葡萄状白云岩成因. 古地理学报, 16(5): 715-725.

[Zhang

, Brian

, Pan L

, Zhou J

, Qin Y

, Hao

, Wu M

. 2014. Origin of botryoidal dolostone of the Sinian Dengying Formation in Sichuan Basin. Journal of Palaeogeography(Chinese Edition), 16(5): 715-725]

Sinian Dengying Formation (up to 1000m) in Sichuan Basin is composed of fine crystalline dolostones. In some parts of the formation(mainly in Members 2 and 4) distributed various shaped botyroidal masses of dolomite,up to 75cm long in maximum. They are either parallel to bedding or cutting across bedding. Those cross sections reveal that isopachous bands of various types of dolomite are developed as cements. Large amount of irregular shaped cavities are still present in the central parts of some larger bodies, which formed as a result of subterranean dissolution that was associated with karst development. The surrounding micritic dolostone was originally deposited from seawater protocrystallization, and the subsequent cements can be divided into four stages:(1)the dolomitized automicrite in some samples was the 1 st stage cement,which formed close to the surrounding micritic dolostone due to various physiochemical and possible biological influences;(2)the 2 nd stage fibrous dolomite had an absolute ordering crystal structure and nearly ideal crystal cell parameter,which may have originated from marine waters and adjusted to be ordered during the late diagenesis;(3)the 3 rd stage fine- to medium-crystal dolomite including residual of fibrous dolomite crystals dissolved in a near-surface meteoric environment after tectonic uplift;(4)the 4 th stage medium-coarse crystal dolomite primarily precipitated under a burial environment and partially filled the central parts of the cavities, with some unfilled cavities. It is apparent that the Dengying Formation was subject to multiple phases of diagenesis including karst development,precipitation of various cements,and multiple episodes of dolomitization. Except the paleokarstification,all of the other processes critically reduced the porosity of the petroleum reservoir that developed in the Dengying Formation. The paleokarstification which related to botryoidal dolostone has crucial importance to the Dengying Formation reservoir. The study of botryoidal dolostone in Sinian Dengying Formation conduces to understand the reservoir origin and evolution of the Dengying Formation dolostone,and guide the Precambrian petroleum development of Sichuan Basin

1 PetroChina Hangzhou Research Institute of Geology,Hangzhou.310023,Zhejiang 2 Key Laboratory of Carbonate Reservoir,CNPC,Hangzhou.310023,Zhejiang 3 Department of Earth and Atmospheric Sciences,University of Alberta,Edmonton,Alberta T6G 2E3 ,Canada 4 Qinghai Exploration Bureau of Environment Geology,Xining.810007,Qinghai

四川盆地震旦系灯影组发育巨厚的白云岩,其中灯影组二段和四段发育大量具有各种形态的葡萄状白云岩,其直径最长可达75cm,有的平行于层面,有的穿层。剖面资料表明,葡萄状白云岩发育多期等厚环边胶结物,中部残留大量未充填的不规则洞穴,这成为与岩溶喀斯特作用相关的地下溶蚀作用的证据。围岩泥晶白云石为早期海水中原生结晶的产物,后来的胶结物可划分为4期: (1)自泥晶化白云石(部分样品中可见)作为最早的一期胶结物,由于各种生物化学作用和生物作用的影响而紧贴着围岩发育;(2)第2期胶结物纤维状白云石可能为海水中直接沉淀的产物,经历后期成岩作用后,具有完全有序的结构,晶胞参数接近理想值;(3)细—中晶白云石为第3期胶结物,包含纤维状白云石溶蚀残余,形成于构造抬升之后的近地表大气淡水环境;(4)第4期胶结物中—粗晶白云石为埋藏环境下直接结晶的产物,充填了孔洞中心,残留部分未充填孔洞。灯影组受到了岩溶喀斯特作用、胶结作用以及白云石化作用等成岩作用的影响,其中与葡萄状白云岩有关的岩溶喀斯特作用对于灯影组储集层的发育至关重要。对灯影组葡萄状白云岩的研究,不仅有助于深入探讨灯影组储集层成因和演化及灯影组白云岩的成因,而且有助于指导四川盆地前寒武系油气勘探。

... 张杰等,2014) ...

2003

0.0

... 1 地质特征上震旦统奇格布拉克组(Z₂_s)是张太荣(张师本等,2003)所厘定的,包括原苏盖特布拉克组上部和肖尔布拉克组下部 ...

1980

0.0

张荫本. 1980. 震旦纪白云岩中的葡萄状构造成因初探. 石油实验地质, (4): 40-43.

[Zhang Y

. 1980. Preliminary study on the botryoidal structures in the Sinian dolostones. Petroleum Geology & Experiment, (4): 40-43]

在我国西南地区发育的震旦系灯影组下段,可以见到具葡萄状构造的云岩。这种具葡萄状构造的云岩在地层分层对比上有一定意义;同时又是天然气的储集空间。地质人员对它的成因十分重视,进行了一系例的研究。本文想通过一些实际资料和图片进行成因探讨。一、对葡萄状构造成因的几种认识四川威远构造上的灯影组天然气含量丰富,产量很高。为此石油勘探者对灯影组的岩性进行了反复分析研究,指出天然气含量与葡萄状构造有关。但对葡萄状构造的成因有二种截然不同的认识。

... 主要认识有: (1)非叠层石生态系的兰细菌构成(张荫本,1980 ...

2009

0.0

... (Anderson and Arthur,2009),由此推断,形成葡萄状或皮壳状结构的白云石及云质灰岩流体温度变化较小(#cod#x0003C ...

2001

0.0

... Cicero and Lohmann,2001 ...

2004

0.0

... 同时还存在呈不发光的斑点或斑块,类似于较为生物膜或、不规则聚集体的原地钙化斑状物(凝块)或生物层孔状构造遗迹,推测为球状蓝细菌微生物占优势的微生物群落所形成(Fl#cod#x000fc ...

2013

0.0

... Eu与基岩相似,上述的轻稀土亏损常指示未经充分分异、保存的海水(Garrison et al ...

... Ce相对较低,比泥粉晶白云岩对应值高,一般指示了弱还原的沉积环境,但负铈异常有多种原因,如硅质陆屑、铁氧化物、含磷等影响(Garrison et al ...

2007

0.0

... Gerdes,2007,2010) ...

2010

0.0

... Gerdes,2007,2010) ...

2013

0.0

... Grant,2013) ...

2007

0.0

... 7094,Halverson et al ...

2003

0.0

... 综上所述,皮壳状、葡萄状白云石形成于稳定的温度条件、弱还原条件海水中、或在成岩早期或浅埋藏残余孔隙(海水)中,推断在间冰期,大量营养物注入海洋,促进了光合作用以及大气的氧化过程(Hardie,2003 ...

2011

0.0

... Hood et al ...

2012

0.0

... Eu及Y异常),反映出主要形成于弱还原下保存较好的海水条件中(Maree Corkeron et al ...

1950

0.0

1967

0.0

2013

0.0

... Susanne et al ...