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作者简介:

乔占峰,男,1983年生。高级工程师,主要从事碳酸盐岩层序地层和沉积储层研究。E-mail:qiaozf_hz@petrochina.com.cn。

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目录contents

    摘要

    地下富镁流体运移机制问题,制约着规模埋藏白云岩形成过程的认识,一直是白云岩成因中地质学家争论的焦点。以塔里木盆地蓬莱坝组埋藏白云岩为研究对象,在岩石学和碳氧同位素、锶同位素与锶元素含量等常规地球化学分析的基础上,通过镁同位素分析,认识了规模埋藏白云岩的形成过程。分析显示,蓬莱坝组不同类型白云岩的镁同位素分布虽有重叠,但是差异明显,藻纹层白云岩镁同位素为-2.34‰~-2.02‰;细中晶残余颗粒白云岩的镁同位素分布范围较广,为-2.24‰~-1.66‰,平均为-2.04‰;粗晶白云岩的镁同位素主要集中在-2.24‰~-1.89,平均为-2.05‰;蓬莱坝组灰岩镁同位素为-3.63‰和-2.82‰,较白云岩明显更偏负。镁同位素与氧同位素、锶同位素和锶元素含量在高频旋回中表现出规律性的旋回变化,对应三种白云岩形成过程:向上变轻-渗透回流叠加埋藏云化、向上变重-蒸发泵叠加埋藏云化和向上变重-埋藏云化模式。进一步,通过白云石晶体变化与锶元素含量变化明确了埋藏云化流体的侧向运移和白云石晶体响应规律。认识到厚层白云岩是由多期白云石化作用叠加而成,既有层内云化流体也受源外云化流体影响,受沉积相和构造埋藏演化史共同控制,海平面波动下大量叠置发育的准同生白云岩是规模埋藏白云岩形成的关键。特别是,基质孔发育的渗透回流型准同生白云岩,在高频层序格架下占比越高、越频繁,越有利于埋藏云化的顺层渗透扩散,进而形成规模埋藏白云岩。

    Abstract

    The formation of large-scale burial dolomite, especially the migration mechanism of magnesium-enriched fluid, has always been the focus of debate among geologists in the genesis of dolomite. Considering the burial dolomite of Penglaiba Formation in Tarim basin, the formation mechanism of massive burial dolomite was studied by integrating magnesium isotope and petrology, conventional geochemical analysis of carbon and oxygen isotopes, strontium isotopes and strontium content. The analysis shows that although the magnesium isotope distribution of different types of dolomites in the Penglaiba Formation overlaps, the difference is obvious. The microbial dolomites have the magnesium isotope value of -2.34‰~-2.02‰ while those of fine to medium crystalline dolomite range from -2.24‰ to -1.66‰, with an average of -2.04‰. The magnesium isotopes of coarse crystalline dolomite are concentrated in -2.24‰~-1.89‰ range, with an average value of -2.21‰. In contrast, the magnesium isotope of limestone of the Penglaiba Formation ranges between -3.63‰ to -2.82‰, which is obviously more negative than that of dolomite. The compositions of magnesium isotope, oxygen isotope, and strontium isotope and strontium contents show regular cyclic changes in high-frequency cycles, corresponding to three processes of dolomitization: upward lightening-reflux superimposed by burial dolomitization, upward weighting-Sabkha superimposed by burial dolomitization, and upward weighting-burial dolomitization. Furthermore, according to the lateral variation of dolomite crystal and strontium content within cycles, the response principle of dolomite crystal in the process of lateral migration of buried dolomitizing fluid is clarified. It is recognized that the massive dolomite is formed by the superposition of multi-stage dolomitization. There are both intralayer dolomitized fluids and exotic dolomitized fluids. It is jointly controlled by sedimentary facies and tectonic burial evolution history. A large number of stacking penecontemporaneous dolomites formed under sea level fluctuations constituting the basis of the large-scale massive burial dolomite, especially the permeable reflux dolomite with considerable primary pores. The higher the proportion of penecontemporaneous dolomite in the high-frequency sequence framework, the more conducive it is to the infiltration and diffusion of dolomitizing fluids under burial conditions, so as to increase the proportion of dolomite and constitute large-scale massive burial dolomite.

  • 白云岩作为一类重要的碳酸盐岩油气储层(Warren,2000),其成因已困扰了科学家二百多年(Machel,2004),多种白云石化作用模式被提出并被证实(Warren,2000),如蒸发泵(Bush,1973)、海水(Land,1985)、渗透回流(Adams et al.,1960)、埋藏(Mattes et al.,1980)、热液(Davies et al.,2006)和微生物白云石化作用(Vasconcelos et al.,1995)等。然而,对于厚度达数百米到上千米的厚层块状白云岩(Massive dolomite)的成因(Land,1985; Warren,2000Lumsden et al.,2001Machel,2004梅冥相,2012)尚无确切可靠的模式可以合理解释,特别是对于镁离子来源和大范围运移过程。

  • 近年高精度镁同位素测试(MC-ICP-MS)和分析取得显著进展(Galy et al.,2001柯珊等,2011甯濛等,2018),为解决镁离子来源和运移过程这一问题提供了可能(Hu Zhongya et al.,2017Bialik et al.,2018Ning Meng et al.,20182020)。与白云岩成因机制存在准同生和埋藏期成因相对应,镁同位素在白云岩中的应用集中在对准同生白云岩(Peng Yang et al.,2016Bialik et al.,2018Hu Zhongya et al.,2019)和埋藏期白云岩(Hu Zhongya et al.,2019)的研究上。Bialik et al.(2018)通过细致的岩石学分析,并与碳、氧、锶同位素以及稀土元素等联合分析,指出Mg同位素对于准同生白云岩形成环境具有较好的应用效果。Ning Meng et al.(2020)根据Mg同位素组成与地层沉积旋回同步变化,指出扬子板块中寒武统覃家庙组厚层块状白云岩为海平面波动控制下的多期准同生白云石化作用在时空上的叠置而形成,该结论符合Peng Yang et al.(2016)提出的流动水(AF)模型。然而,对于埋藏白云岩中镁同位素的应用存在争议。前人研究指出,温度对白云岩Mg同位素组成影响不大,成岩流体的改造是白云岩Mg同位素组成的重要影响因素(Geske et al.,2012,2014;Azmy et al.,2013; Li Fangbing et al.,2016);然而,Hu Zhongya et al.(2019)指出准同生形成的白云岩的Mg同位素受后期成岩改造的影响较弱,尚未形成统一的认识。特别是对于埋藏白云岩,由于形成过程的差异、云化流体来源的复杂性和成岩后期的改造等多因素影响,造成镁同位素的响应仍需进一步探索。

  • 塔里木盆地蓬莱坝组为典型的埋藏白云岩(顾家裕,2000; 邵龙义等,2002; 朱井泉等,2008; 赵文智等,2012; 乔占峰等,20122020郑剑锋等,2013),在塔里木盆地阿克苏地区出露较好,有利于在白云岩发育规律的基础上,通过岩石学和地球化学认识白云岩成因。乔占峰等(2020)在岩石学和常规同位素地球化学的支撑下,应用激光U-Pb定年梳理出两种成因的埋藏白云岩,即准同生成因白云岩经埋藏重结晶后形成的I型埋藏白云岩和灰岩在埋藏期发生交代作用形成的II型埋藏白云岩,有利于认识在不同埋藏白云岩形成路径情况下的镁同位素响应。

  • 本文以塔里木盆地蓬莱坝组典型埋藏白云岩为研究对象,在地质研究的基础上,结合常规碳、氧、锶同位素和微量元素分析,开展系统的镁同位素分析,以期解决两个问题:一是探索镁同位素在埋藏白云石成因研究中的应用;二是认识埋藏白云岩镁同位素来源和运移机制,对于提升埋藏白云岩成因认识具有重要推动作用。

  • 1 地质背景

  • 塔里木盆地是位于中国西北部的一个大型叠合盆地,面积53×104 km2,发育三隆(塔北隆起、塔中隆起和塔南隆起)和四坳(库车凹陷、北部凹陷、塔西南凹陷和塔东南凹陷)(图1a)。在寒武系—奥陶系沉积期间,塔里木盆地西部为一大型碳酸盐岩台地沉积,经历了从早寒武世到晚寒武世和早奥陶世到中晚奥陶世两次缓坡到镶边台地的沉积旋回,其中早寒武世—晚寒武世为被动陆缘背景下的碳酸盐岩沉积,以受海平面变化为主要控制,中晚寒武世随海平面上升形成大型镶边台地,台地内部发育大规模的膏盐岩沉积;早奥陶世后,受加里东运动的影响,塔里木盆地转变为挤压应力背景,并从中奥陶世开始塔里木盆地西侧碳酸盐岩台地发生分异,满加尔凹陷南北两侧分别发育塔中隆起和塔北隆起雏形,在其上发育镶边碳酸盐岩台地,在海西期塔北隆起和塔中隆起发生大规模抬升,基本定型。

  • 本次研究重点永安坝剖面位于巴楚隆起西缘,巴楚隆起西北紧邻柯坪冲断带,向东连接塔中隆起(图1b)。巴楚隆起和柯坪断隆在新生代以前是统一的古隆起(张臣等,2001),经历了加里东期、海西期、印支—燕山期和喜马拉雅期四个构造旋回,海西早期开始显现雏形,到海西中晚期,隆起形成,并于喜马拉雅期强烈隆升,并最终定型(丁文龙等,2012)。发育一系列北西向断裂,终止于柯坪断隆(图1b)。

  • 图1 塔里木盆地区域地质背景图

  • Fig.1 The regional geological setting of Tarim basin

  • (a)—塔里木盆地构造区划图与工区位置图;(b)—巴楚隆起断裂发育图与永安坝剖面位置图;(c)—中下奥陶统地层岩性柱状图;(d)—永安坝剖面露头照片与实测剖面位置图

  • (a) —structure zonation map of Tarim basin and location of the studied area; (b) —faults map in Bachu uplift and location of Yonganba outcrop; (c) —stratigraphic column of Lower to Middle Ordovician; (d) —photography of Yonganba outcrop and the location of measured profiles

  • 塔里木盆地下奥陶统蓬莱坝组沉积于缓坡背景,围绕塔西南、塔中和塔北三个次级古隆起发育内缓坡,沿满加尔凹陷周缘为中缓坡(熊冉等,2019)。巴楚地区处于中缓坡带,以潮下—潮间带沉积为主(朱莲芳等,1991),未见典型潮上带现象,由向上变浅米级旋回叠置而成。

  • 巴楚地区蓬莱坝组沉积后即进入埋藏期,在晚奥陶世期间受加里东运动影响发生小幅抬升,随后在志留纪—泥盆纪持续埋藏,埋深达到2000 m,于晚泥盆世开始,受早海西构造运动影响发生较显著抬升,幅度可达近500 m,晚石炭世—二叠纪期间,受晚海西构造运动影响,发生快速沉降到2500 m左右埋深后,又快速抬升到地表出露(胡明毅等,图2),进入表生期阶段。

  • 图2 巴楚地区蓬莱坝组埋藏史与白云石年龄分布图 (据乔占峰等,2020修改;埋藏史据胡明毅,1993)

  • Fig.2 The burial history of Penglaiba Formation in Bachu area and the ages of dolomite (after Qiao Zhanfeng et al., 2020; burial history after Hu Mingyi, 1993)

  • 巴楚地区露头区蓬莱坝组与下伏丘里塔格组和上覆鹰山组呈整合接触(图1c),底部和顶部主要由灰岩构成,夹白云岩;中部主要由白云岩构成,夹少量灰岩和辉绿岩层,白云岩厚达200 m(图2),横向延伸可达100 km,被认为是典型的埋藏白云石化作用成因(胡明毅等,1991; 顾家裕,2000; 杨威等,2000; 邵龙义等,2002; 朱井泉等,2008; 赵文智等,2012; 乔占峰等,2012郑剑锋等,2013),为本研究的主要对象。

  • 2 样品及实验方法

  • 针对永安坝剖面出露较好的蓬莱坝组中下部白云岩段,实测三条剖面(图1d),剖面间隔50~100 m,详细描述白云岩类型和旋回叠置关系。进一步,针对不同类型白云岩和灰岩旋回进行系统取样,钻样深度为10~15 cm,取下部5 cm开展地球化学分析,以尽可能减少风化影响。共选择74件样品进行镁同位素、碳氧锶同位素和微量元素的系统分析。

  • 镁同位素测试使用热电公司的Neptune Plus多接收电感耦合等离子体质谱仪。称取20 mg白云岩样品溶解到1 mol/L HNO3中得到上清液,使用Bio-Rad AG50W-X8树脂(200~400目)分离Mg和其他元素,为了保证Mg和其他元素分离完全,需要经过两次化学柱的分离,同时保证Mg的回收率大于99%,全流程空白小于10 ng。测试过程采用标样-样品-标样穿插测试的方式进行,以便校正仪器的漂移。每个样品测试4次以上,最后计算相对于标样DSM3的同位素值。使用JDo-1作为流程监控标样,测试结果为2.36‰±0.08‰(2σ),与文献中的推荐值在误差范围内一致(Teng Fangzhen,2017)。镁同位素的最终表达形式如下公式所示:

  • δxMg=[(xMg/24Mg)sample/(xMg/24Mg)DSM3-1]×1000‰,x代表质量数25或26。

  • 激光碳、氧同位素测试于LA-IRMS,激光设备(LA)由Nd:YAG(钇铝石榴石)近红外激光器、冷却系统、显微影像系统及气体传输、分离系统组成,ND:YAG激光器输出波长为1064 nm的近红外相干激光束,束斑大小优于20 μm,使用氪灯作为ND:YAG激光器的泵浦能源,工作电流为7~20 A,产生7~40 W输出能量,样品穿透深度为30~50 μm,稳定气体同位素仪器型号为Detla V Advantage。激光剥蚀过程中采用氦气作载气,激光与碳酸盐作用产生CO2气体,经过杂气分离、纯化得到纯的CO2气体,进入同位素质谱仪测试分析。本次分析的激光束斑和电流分别为20 μm和14~20 A,激光采用连续(CW)输出方式,分析数据校正采用的标样是国标GBW04405及实验室内部标样811,分析数据处理采用赛默飞世尔软件ISODAT3.0完成,以PDB表示。δ13C和δ18O的测试精度分别为±0.1‰和±0.2‰。激光斑束直径500 μm,仅测试细晶白云石和中粗晶白云石内核,并对部分粗晶白云石内可识别的原颗粒和胶结物残留阴影进行了测试,作为对比测试了灰岩中白云石晶体和方解石胶结物。

  • 锶同位素测试于固态质谱仪和IVP-MS(X Series II)。称取100~150 mg粉末样,用1∶1的HNO3和HF混合液在190℃下溶解48 h,采用常规流程(Baadsgard,1987)提取出锶同位素并进行测试,标样为NBS987。87Sr/86Sr比值测试平均误差为±0.5×10-5

  • 微量元素为全岩粉末样分析,测试于电感耦合等离子体质谱仪(ICP-MS),型号热电(Thermo Fisher)iCAP RQ,自动进样器型号:CETAC 560。50~100 mg粉末样在185℃溶解于0.6 mL HNO3和2.5 mL HF的混合液72 h。干燥后,与4 mL 20%混合酸(HCl∶HNO3=4∶1)在130℃条件下反应3 h。去除酸液后,溶解物在等离子体质谱仪中采用标准流程进行测试。测试标样为USGS的W-2a,上机溶液含4个内标:Rh、In、Re和Bi。测试精度0.1 ×10-9,误差5%±。

  • 各项实验分析均在中国石油天然气集团公司碳酸盐岩储层重点实验室进行。

  • 3 白云岩岩石学特征

  • 3.1 白云岩类型与特征

  • 乔占峰等(2020)对永安坝剖面蓬莱坝组岩石类型和特征进行了介绍。实测剖面以发育白云岩为主,夹有中厚层状砂屑灰岩和少量透镜状或结核状硅质岩。白云岩根据晶体大小以及结构特征,可识别出粉细晶微生物白云岩(D1)、细中晶(残余颗粒)自形—半自形白云岩(D2)和中粗晶他形白云岩(D3)三种类型。

  • 微生物白云岩(D1)薄片下可见藻纹层为泥晶白云石构成,纹层间由细晶白云石构成,具雾心亮边结构(图3a、b),阴极发光下晶体不发光,晶体边缘发亮橙色光(图3c)。

  • 细中晶(残余颗粒)白云岩薄片下为晶粒结构,晶间孔发育(图3d),恢复结构后识别出颗粒结构,颗粒部位的白云石晶体相对较细小,颗粒间胶结物为细晶,晶体相对更大,晶间孔属粒间孔(图3e),阴极发光下为昏暗发光,可识别出环带结构(图3f)。

  • 粗晶白云岩由他形粗晶白云石构成,晶体呈镶嵌状(图3g),原岩结构无法恢复,晶体内隐约可见颗粒结构,白云石与原岩结构无关(图3h),阴极发光下白云石晶体为暗橙色光,晶间部位发亮橙色光,与暗橙色光部分呈齿状交错(图3i)。

  • 3.2 白云岩旋回叠置关系

  • 露头观察显示,实测剖面白云岩具有两种典型的叠置类型:叠层石→细中晶(残余颗粒)白云岩→藻纹层白云岩旋回和泥晶灰岩/粉晶白云岩→颗粒灰岩/中粗晶白云岩→细中晶(残余颗粒)白云岩旋回。

  • (1)叠层石白云岩→细中晶(残余颗粒)白云岩→泥粉晶白云岩旋回:该旋回为向上变细旋回,完整的结构具有三段式。底部为微生物白云岩,以叠层石为典型特征,单层厚约10~30 cm,多见较规则的穹隆状叠层石,单个叠层石高度可达30 cm,向上规则生长,代表潮下带较稳定水体特征;向上过渡为细中晶(残余颗粒)白云岩,其中发育双向交错层理,代表潮下带上部到潮间带下部环境潮汐水动力加强,顶部为薄层状藻纹层白云岩或泥粉晶白云岩,厚约10~20 cm,颜色为暗紫红色,代表潮间上部到潮上带暴露氧化环境,构成完整的向上变细旋回(图4a)。需要指出的是,以上三段式旋回结构并不总是完整发育,可发育为叠层石白云岩→细中晶(残余颗粒)白云岩,或细中晶(残余颗粒)白云岩→泥粉晶白云岩或藻纹层白云岩。这种旋回特征代表了潮坪背景下,完整的海平面上升到下降的旋回特征,海平面上升初期处于潮下—潮间下部叠层石开始发育,在海平面下降过程中进入潮间带以高能颗粒沉积为主,发育交错层理,旋回末期进入潮间带上部或潮上带,发育藻纹层或薄层灰泥沉积,顶部氧化环境沉积物显红色特征。

  • (2)泥晶灰岩/粉晶白云岩→颗粒灰岩/中粗晶白云岩→细中晶(残余颗粒)白云岩旋回:该旋回为典型的向上变粗旋回,露头上都表现为底部薄层向上变为中厚层,上部多发育交错层理。完整旋回的岩性结构为薄层状泥晶灰岩→中厚层状颗粒灰岩→中厚层状中粗晶白云岩→中层状细中晶(残余颗粒)白云岩,可存在多种表现,包括:薄层状粉晶白云岩→中厚层状中粗晶白云岩(图4b)、薄层状泥晶灰岩→中厚层状颗粒灰岩(图4c)等。其中,中厚层状颗粒灰岩中可夹有或上覆中粗晶白云岩,接触部位的颗粒灰岩中多见沿缝合线发育的中粗晶白云石团块。该旋回中,白云岩的发育与沉积旋回存在一定的不一致性,与前人的埋藏白云岩成因解释相一致。

  • 图3 巴楚地区永安坝剖面蓬莱坝组白云岩类型与特征图版

  • Fig.3 Types and petrographic features of Penglaiba Formation dolomites of Yonganba outcrop in Bachu area

  • (a)—微生物白云岩,可见藻纹层呈暗色条纹状,纹层间白云石具雾心亮边特征,常规薄片照片;(b)—视域同(a),藻纹层泥粉晶特征清晰,发育少量晶间孔,原岩结构恢复照片;(c)—阴极发光照片,白云石主体不发光,晶体边缘发橙色光;(d)—细中晶(残余颗粒)白云岩,粒间部位的白云石晶粒略大,粒间孔发育,常规薄片照片;(e)—视域同(d),颗粒结构清晰,粒间孔特征明显,原岩结构恢复照片;(f)—阴极发光照片,白云石为昏暗发光,具暗橙色环边;(g)—中粗晶白云岩,白云石多为他晶,晶体内部不均匀,常规薄片照片;(h)—视域同(g),白云石晶体内可见颗粒结构特征,原岩结构恢复照片;(i)—阴极发光照片,白云石主体发暗橙色光,颗粒间亮橙色光不均匀发育,表现为向晶体内渗透的特征

  • (a) —microscopic photography of microbial dolomite; (b) —fabric restored picture of (a) ; (c) —cathodoluminescene photo of microbial dolomite; (d) —microscopic photography of fine to medium crystalline dolomite with the ghost of grainstone texture; (e) —fabric restored picture of (d) ; (f) —cathodoluminescene photo of fine to medium crystalline dolomite with the ghost of grainstone texture; (g) —microscopic photography of medium to coarse crystalline dolomite; (h) —fabric restored picture of (g) ; (i) —cathodoluminescene photo of medium to coarse crystalline dolomite

  • 图4 巴楚地区永安坝剖面典型岩石旋回露头照片

  • Fig.4 Field photo showing the typical lithological cycles of Penglaiba Formation in Yonganba outcrop in Bachu area

  • (a)—叠层石→细中晶(残余颗粒)→藻纹层白云岩旋回;(b)—粉晶白云岩→中粗晶白云岩旋回;(c)—泥晶灰岩→颗粒灰岩旋回

  • (a) —stromatolite to fine-medium crystalline dolomite with the ghost of grainstone texture to reddish laminated microbial dolomite; (b) —fine crystalline dolomite to medium-coarse crystalline dolomite cycle; (c) —mudstone to grainstone cycle

  • 4 地球化学分析结果

  • 蓬莱坝组不同类型白云岩和灰岩的地球化学分析结果统计见表1。

  • 4.1 镁同位素

  • 由于Mg在海水中具有较长(大于10 Ma)的居留时间(Li Yuanhui,1982),较短时期内在海水中已经充分混合并达到同位素组成均一,因此海水具有较为统一的Mg同位素比值,现今海水Mg同位素比值为-0.83‰±0.07‰(柯珊等,2011)。规模白云岩形成的关键在于大量的富镁离子流体的运移,而富镁流体运移中镁同位素会发生一定程度的分馏(Peng Yang et al.,2016Ning Meng et al.,2018),因此镁同位素对于云化流体来源和白云岩的形成或演化过程具有一定的指示意义。分析显示,蓬莱坝组不同类型白云岩的镁同位素分布虽有重叠,但是差异较明显(表1,图5)。藻纹层白云岩仅有4个样品,镁同位素为-2.34‰~-2.02‰;细中晶残余颗粒白云岩的镁同位素分布范围较广,为-2.24‰~-1.66‰,平均为-2.04‰;粗晶白云岩的镁同位素与细中晶白云岩的分布范围有明显不同,除两个样品分别为-1.60‰和-1.68‰,其余样品集中在-2.24‰~-1.89‰,平均值为-2.05‰;相比之下,蓬莱坝组灰岩镁同位素为-3.63‰和-2.82‰,较白云岩明显更偏负。

  • 表1 巴楚地区永安坝剖面蓬莱坝组不同类型白云岩和灰岩地球化学分析结果

  • Table1 Geochemistry features of different types of dolomite and limestone of Penglaiba Formation of Yonganba outcrop in Bachu area

  • 续表1

  • 注:样品编号带*号的碳、氧、锶同位素和锶含量据乔占峰等,2020

  • 4.2 碳、氧、锶同位素

  • 不同类型白云岩和灰岩的碳、氧、锶同位素分布存在较明显的差异(图6)。藻纹层白云石碳、氧同位素分布较为集中,为-1.3‰~-0.74‰和-8.04‰~-6.05‰(图6a);细中晶白云石碳和氧同位素分别为-1.37‰~-0.36‰和-8.59‰~-3.75‰;粗晶白云石具有较接近的氧同位素(-8.88‰~-5.77‰)和较离散的碳同位素(-1.89‰~-0.46‰),明显较细中晶白云石更偏负;灰岩的碳、氧同位素明显更偏负,分别为-1.25‰~-0.65‰和-11.81‰~-8.07‰。

  • 图5 巴楚地区永安坝剖面不同类型白云岩和灰岩镁同位素分布图

  • Fig.5 Plots showing the distribution of Mg isotope compositions of different types of dolomite and limestone of Yonganba outcrop in Bachu area

  • 藻纹层白云岩的锶同位素比值主要为0.709057~0.709075,仅一个样品比值较高,为0.709813(图6b);细中晶白云岩的锶同位素比值分布范围较广,为0.708834~0.709688;中粗晶白云岩和灰岩的锶同位素比值分布较为集中,为0.709034~0.709435,接近早奥陶世海水锶同位素比值(0.7091;黄文辉等,2006)。不同类型岩石的锶同位素比值和碳、氧同位素均未表现出明显的协同变化(图6c、d),其中细中晶白云岩似乎具有锶同位素升高、氧同位素变偏负的趋势。

  • 4.3 锶元素含量

  • 不同类型白云石总体上未表现出显著的锶元素含量差异。各类白云石Sr含量均小于300×10-6,其中藻纹层白云岩为100×10-6~300×10-6,而细中晶白云岩和粗晶白云岩多小于200×10-6。相比之下,灰岩具有较高Sr含量,部分可达700×10-6

  • 5 解释与讨论

  • 5.1 白云岩成因

  • 众多学者已指出塔里木盆地蓬莱坝组白云岩为埋藏成因(顾家裕,2000邵龙义等,2002; 朱井泉等,2008; 赵文智等,2012; 乔占峰等,20122020郑剑锋等,2013)。乔占峰等(2020)进一步根据成岩序列和激光U-Pb定年技术提出蓬莱坝组白云岩可划分为两种埋藏白云岩类型,即:细中晶白云岩等在准同生期云化作用的基础上在埋藏期叠加重结晶改造而形成的I型埋藏白云岩;和灰岩在埋藏期经交代作用改造直接形成的II型埋藏白云岩,表现为中粗晶白云岩。

  • 细中晶白云岩激光U-Pb定年为464±12 Ma和441±16 Ma(图2),对应早奥陶世—早志留世,代表浅埋藏期年龄,结合其阴极发光和稀土元素面扫揭示的环带特征,以及白云石晶体排列明显的组构约束特征,推知其在准同生期已发生白云石化作用。晶体特征和定年结果对比也可知,重结晶强度越大,年龄越新,代表了浅埋藏期重结晶的作用过程。同位素分布也显示,其具有相对偏正的碳、氧同位素和较高的锶同位素,以及较低的锶元素含量,代表了重结晶改造的结果(Mazzullo,1992)。

  • 中粗晶白云岩晶核和晶缘以及颗粒灰岩中斑状白云石的定年结果揭示了其埋藏成因的特点。中粗晶白云岩晶核和颗粒灰岩中斑状白云石的年龄分别为433±22 Ma和443±18 Ma,而中粗晶白云岩晶缘的有效年龄为382±29 Ma(图2),代表了自浅埋藏期初始形成,又在泥盆纪埋藏期再次经过流体改造的云化过程。其晶体在阴极发光和稀土元素面扫下均匀的发光特点,以及其与颗粒灰岩中斑状白云石高度相似的特点,揭示了其在埋藏期由灰岩缓慢扩散形成的特点,代表了水岩比低的岩石缓冲体系,也因此导致,其碳、氧同位素与灰岩更为接近。

  • 图6 巴楚地区永安坝剖面不同类型白云石碳、氧、锶同位素和锶元素含量相关图

  • Fig.6 Crossplots showing the relationships of carbon, oxygen, and strontium isotope compositions and strontium contents of different types of dolomite and limestone of Yonganba outcrop in Bachu area

  • 5.2 白云石镁同位素信号

  • 镁同位素对于指示镁离子来源及云化过程有重要的意义(Geske et al.,2015Huang Kangjun et al.,2015Li Fangbing et al.,2016)。甯濛等(2018)综述到不同时代白云岩的镁同位素组成并没有规律性变化,不同类型白云岩的镁同位素组成也无系统性差异(Geske et al.,2015Huang Kangjun et al.,2015)。本次研究展示的下奥陶统蓬莱坝组白云岩镁同位素分布范围也与文献发表的同时代白云岩镁同位素值接近,如塔里木盆地井下蓬莱坝组白云岩镁同位素平均约为-2.06‰±0.20‰(Hu Zhongya et al.,2019),东Laurentia地区Watts Bight和Boat Harbour组白云岩为-2.27‰~-1.80‰(Azmy et al.,2013)。但是,研究剖面蓬莱坝组镁同位素与碳、氧、锶同位素和锶含量的交汇分析,显示不同类型白云岩之间具有较为明显的区分度(图7),可能反映了云化流体来源的差异以及云化过程的特征。

  • 藻纹层白云岩表现出与细中晶白云岩和中粗晶白云岩明显不同的分布范围(图7a、b),镁同位素相对更为偏负。根据碳、氧、锶同位素特征可知,藻纹层白云岩代表了准同生白云岩成因特征,其镁同位素可能也代表了准同生白云岩的镁同位素分布区间,对应地,其与细中晶白云岩和中粗晶白云岩间明显不同的镁同位素揭示,后者的形成演化可能受到埋藏成岩改造的影响,与碳、氧、锶同位素揭示的信息一致。

  • 中粗晶白云岩与细中晶白云岩的镁同位素分布重叠严重(图7a、b)。Peng Yang et al.(2016)指出白云岩的镁同位素受云化流体的镁同位素组成、流体迁移速率、反应速率以及镁同位素分馏等因素控制,其中云化流体的镁同位素组成起着关键作用。因此,总体上来看,粗晶白云岩与细中晶白云岩镁同位素分布范围的明显重叠,也可能揭示了二者均显示了海源地层流体的信息,与岩石学与碳、氧、锶同位素研究得出的认识是一致的。

  • 图7 巴楚地区永安坝剖面蓬莱坝组不同类型白云岩和灰岩镁同位素与碳、氧、锶同位素和锶含量交汇图

  • Fig.7 Crossplots showing the relationships of magnesium isotope compositions and carbon, oxygen, and strontium isotope compositions and strontium contents of different types of dolomite and limestone of Yonganba outcrop in Bachu area

  • 此外,需要进一步指出的是,中粗晶白云岩和细中晶白云岩的镁同位素分布范围均非常广(图7 a、b),可能代表了镁同位素分馏的结果,需结合镁同位素地球化学模型进行分析(甯濛等,2018)。对于细中晶白云岩,其原始孔隙较发育,云化流体流动相对畅通,水岩比大,适合流动水模型(Peng Yang et al.,2016):云化流体运移方向,镁同位素逐渐变正;白云石形成速率加快,镁同位素变正;流体迁移速率加快,则偏负(Peng Yang et al.,2016)。相比之下,粗晶白云岩形成过程中水岩比低,以扩散交代为主要形成过程,适合于扩散对流反应模型(Huang Kangjun et al.,2015):白云岩形成速率加快,云化程度加大,镁同位素趋向于变轻;并且早期形成的白云岩比晚期形成的白云岩的镁同位素轻(Huang Kangjun et al.,2015)。两种白云岩适用于两种不同的地球化学模型,结果导致镁同位素值的变化难以进行区分,如流动水模型中,白云石形成速率加快镁同位素变正,而流体迁移速率加快则变轻;而扩散模型中,白云石形成速率加快,镁同位素变轻。因此,无法单独依靠数值的比较进行成因的判断(Geske et al.,2015Huang Kangjun et al.,2015)。

  • 5.3 同位素旋回性变化分析

  • 尽管数值点的差异不足以说明白云岩成因上的差异,但是根据白云石镁同位素组成随流体的迁移方向具有逐渐变正的趋势特点(Peng Yang et al.,2016),可以通过镁同位素在地层格架下的变化分析白云石化流体的运动轨迹。将实测的镁同位素、氧同位素、锶同位素和锶含量投点到对应的取样位置可知,在层序旋回中和剖面间表现出较好的变化趋势(图8)。在单一高频旋回内,镁同位素可具有较显著的数值变化,具有向上变负或向上变正的旋回特点,且伴随碳、氧、锶同位素和锶含量的旋回变化。

  • 结合不同旋回白云岩的岩石学变化特征可知,镁同位素垂向变化存在3种类型:向上变轻、向上变重、向上变重再变轻,对应云化流体运移方向的差异。

  • 5.3.1 镁同位素向上变轻旋回-渗透回流叠加埋藏云化模式

  • 这种旋回发育于实测剖面下部的颗粒灰岩—中粗晶白云岩—细中晶白云岩旋回中,表现出镁同位素向上变轻,伴随着氧同位素向上变正、锶同位素向上升高、锶含量向上降低(图9)。旋回中样品覆盖颗粒灰岩、中粗晶白云岩和细中晶白云岩,白云岩段中明显上部样品晶体更为细小,孔隙更为发育,下部样品晶体较大且与灰岩伴生(图9)。这种旋回特征可分别利用流动水模型和扩散模型进行解释。

  • 图8 巴楚地区永安坝剖面蓬莱坝组岩性与地球化学对比图(剖面位置见图1)

  • Fig.8 Correlation profile of measured sections showing the cycles of magnesium, oxygen, and strontium isotope compositions and strontium contents of Yonganba outcrop in Bachu area (outcrop location shown in Fig.1)

  • 流动水模型中,云化流体迁移速率快会导致白云石镁同位素偏负(Peng Yang et al.,2016),旋回中上部样品孔隙明显发育、连通性好,更有利于流体快速运移,从而导致其镁同位素明显较下部样品更加偏轻。在该模型下,结合白云石镁同位素组成随流体的迁移方向具有逐渐变正的趋势特点(Peng Yang et al.,2016),可推断该旋回符合回流渗透云化模式,云化流体自上而下运移,导致白云石化作用发生。

  • 扩散对流反应模型中,白云岩形成速率加快,云化程度加大,镁同位素趋向于变轻;并且早期形成的白云岩比晚期形成的白云岩的镁同位素轻(Huang Kangjun et al.,2015)。旋回中,上部样品更具典型的重结晶特点,且显示出明显的残余颗粒结构,显示其形成更早,云化程度更高;而下部样品晶体较大程度上呈镶嵌状接触,晶体表面欠干净,代表可能发育更多的方解石包裹体,云化程度相对较低。

  • 结合岩石学特征和氧同位素、锶同位素和锶元素含量的变化趋势认为,该旋回本身兼具流动水模型和扩散对流反应模型的特征。由于旋回上部细中晶残余颗粒白云岩孔隙发育,云化流体优先自上部流动,云化流体流速更大,白云石化发生更早;下部旋回相对孔隙欠发育,云化流体从上部缓慢下渗,水岩比小,白云石化发生相对更晚,导致镁同位素上部偏轻、下部偏重。而云化过程中,由于锶元素配分系数小于1,上部白云岩孔隙发育、埋藏重结晶改造强烈,因此具有更低的锶元素含量和更高的锶同位素比值。以上分析可知,该旋回可能代表了准同生渗透回流和埋藏白云石化作用叠加改造的综合结果。该认识与激光U-Pb定年分析结果相一致。

  • 5.3.2 镁同位素向上变重旋回

  • 该旋回类型在细中晶白云岩和中粗晶白云岩构成的旋回中都有发育(图10、11)。

  • (1)细中晶白云岩旋回-蒸发泵叠加埋藏云化模式:该旋回由下部颗粒灰岩、中部细中晶残余颗粒白云岩和上部粉细晶白云岩构成(图10)。针对旋回中部细中晶白云岩的分析显示,白云岩中原岩结构特征保存程度向上逐渐变差,晶体自形程度具变好的趋势;地球化学方面,镁同位素向上变重、氧同位素向上偏正、锶同位素向上增加、锶元素含量向上减少,具有较好的对应性。综合岩石学和地球化学旋回特点,认为该旋回镁同位素特征符合流动水模型(Peng Yang et al.,2016):云化流体运移方向,镁同位素逐渐变正;白云石形成速率加快,镁同位素变正(Peng Yang et al.,2016)。在向上重结晶程度加强的同时,锶同位素比值升高且锶元素含量降低,这一趋势很容易被误认为是代表埋藏环境中重结晶作用导致的结果。但是,该旋回中,氧同位素向上逐渐偏正的特点与以上解释不相吻合,埋藏环境重结晶强度增加应具有向上偏负的氧同位素趋势,而不是向上偏正的趋势。该旋回较大程度保留了准同生期云化作用的信息,准同生期潮坪背景下蒸发泵模式使得云化流体向上运移,上部优先发生运移,导致镁同位素向上变重。该解释也与旋回顶部粉细晶白云岩的发育相一致。至于上部重结晶程度更强烈的情况下,镁同位素仍保留向上变重的旋回特点,可能与Hu Zhongya et al.(2019)指出的白云石镁同位素不受后期成岩流体改造影响相吻合。

  • 图9 巴楚地区永安坝剖面蓬莱坝组镁同位素向上变轻旋回岩石学与地球化学综合柱状图

  • Fig.9 Column showing the microscopic feature and the cycles of magnesium, oxygen, and strontium isotope compositions and strontium contents of reflux dolomitization modified by burial dolomitization of Yonganba outcrop in Bachu area

  • 图10 巴楚地区永安坝剖面蓬莱坝组镁同位素向上变重旋回(蒸发泵叠加埋藏云化)岩石学与地球化学综合柱状图

  • Fig.10 Column showing the microscopic feature and the cycles of magnesium, oxygen, and strontium isotope compositions and strontium contents of Sabhka dolomitization modified by burial dolomitization of Yonganba outcrop in Bachu area

  • 图11 巴楚地区永安坝剖面蓬莱坝组镁同位素向上变重旋回(埋藏云化)岩石学与地球化学综合柱状图

  • Fig.11 Column showing the microscopic feature and the cycles of magnesium, oxygen, and strontium isotope compositions and strontium contents of burial dolomitization of Yonganba outcrop in Bachu area

  • (2)粗晶白云岩旋回-扩散对流埋藏云化模式:该旋回底部发育一层藻纹层白云岩,中上部为粗晶白云岩,岩相恢复后在粗晶白云岩中也可以识别出原始颗粒结构,但是细致分析可知,该类粗晶白云石与颗粒结构本身并无关系,白云石边界可切割原岩中的颗粒和胶结物所有组构,且白云石呈镶嵌状接触(图11)。旋回总体上,向上白云石自形程度更高,部分为自形中晶白云石。对应地,同位素也发育明显的趋势性特征,其中镁同位素向上偏重、氧同位素向上偏负、锶同位素比值向上增加、锶元素含量向上减少(图11)。粗晶白云石的非组构选择性排列、镶嵌状接触关系等岩石学特征决定,该旋回白云岩的形成为低水岩比条件下的灰岩直接云化的结果,更符合扩散对流反应模型(Huang Kangjun et al.,2015):白云岩形成速率加快,云化程度加大,镁同位素趋向于变轻;并且早期形成的白云岩比晚期形成的白云岩的镁同位素轻(Huang Kangjun et al.,2015)。然而,岩石学旋回特征和镁同位素旋回特征表现一定的不一致性。根据岩石学分析可知,旋回向上云化程度更高,上部样品甚至发生一定的重结晶,局部为较自形的中粗晶白云岩,对于两个粗晶白云岩样品来说,应该上部样品形成更早、速率更快,理应具有更轻的镁同位素,但结果上部样品镁同位素略偏重(当然,该样品误差范围相对较大)。但是从氧同位素、锶同位素和锶元素含量来看,与白云岩岩石学特征反应的重结晶强度是一致的,符合埋藏条件下灰岩云化的特点,具有锶含量逐渐降低、锶同位素升高、氧同位素逐渐偏负的趋势特点。因此,综合岩石学和常规同位素旋回特征,对镁同位素的旋回特点给出两个解释:一是该旋回白云石化自下而上发生,底部微生物白云岩形成最早,镁同位素最为偏负,之后在埋藏期云化流体自下而上逐渐导致上部颗粒灰岩云化,导致镁同位素向上变重的结果,在随后的白云石重结晶过程中,镁同位素未受影响,而常规的氧同位素、锶同位素和锶元素含量受到了重结晶作用的改造;二是该旋回白云石化自上而下扩散云化形成,但是粗晶白云石中方解石包裹体的发育导致镁同位素误差较大。X射线衍射分析显示,该类粗晶白云石中或多或少发育一定量方解石包裹体,导致镁同位素结果中可能含有方解石的镁同位素组分,代表了方解石和白云石的两端元混合模型特点(Peng Yang et al.,2016Hu Zhongya et al.,2017),两个样品镁同位素值较接近,且上部样品误差较大,也指示了这种解释的可能性。综合对比分析,底部尽管微生物白云岩具有较早发生白云石化的条件,也具有重结晶改造的特征,但是其本身孔隙不发育,其中云化流体量有限,不足以自下而上导致上覆颗粒灰岩完全云化。结合前人指出的镁同位素受晚期成岩改造影响较弱的特点(Hu Zhongya et al.,2019),笔者更倾向于后一种解释,即上覆孔隙层作为疏导层,云化流体埋藏期自上而下导致颗粒灰岩白云石化。

  • 5.4 锶元素含量侧向变化

  • 在二维解剖窗中密集取样测定的锶含量变化揭示了埋藏云化流体迁移与云化过程。针对单一小层密集取样分析其矿物岩石学和地球化学特征,揭示了同小层内细中晶白云岩—粗晶白云岩—颗粒灰岩斑状白云石的侧向接触关系中,锶含量逐渐升高,代表了成岩强度由强逐渐变弱的趋势,对应着云化流体侧向作用趋势(图12)。细中晶白云岩具有更高的初始孔隙度,作为最初的云化流体运移通道,发生云化作用或重结晶作用,随着云化过程的持续,云化流体逐渐向颗粒灰岩渗入,导致云化作用或交代作用发生,但是由于围岩孔隙欠发育,水岩比低,云化缓慢,可能以扩散交代为主要方式,表现为镶嵌状的粗晶白云岩;云化流体末端终止于致密颗粒灰岩,仅局部残留的孔隙附近发育斑状白云石。

  • 颗粒灰岩中的斑状白云石产于粒间或沿缝合线分布,说明它是由颗粒灰岩直接交代而成。此外,颗粒灰岩中的斑状白云石的薄片中位于粒间的斑片状白云石和单独分布的白云石均有出现,且与粗晶白云岩具有相似的岩石学特征和阴极发光特征,说明二者成因相同,因此颗粒灰岩中的斑状白云石和粗晶白云岩共同构成了完整的埋藏环境交代作用成岩模式(图12)。

  • 5.5 规模白云岩的形成过程

  • 以上分析可知,蓬莱坝组厚层白云岩是由多期白云石化作用叠加作用而成,既有层内云化流体也受源外云化流体影响,受沉积相和构造埋藏演化史共同控制。

  • 综合岩石学和地球化学,特别是氧、锶和镁同位素的垂向变化旋回特征,认为规模白云岩由一系列向上变浅的高频旋回叠置而成,旋回中上部易于受蒸发泵或渗透回流白云石化作用改造,首先转变为白云岩(图13a)。同期地层中部分颗粒沉积较早地发生云化,使得其中的基质孔在浅埋藏期可以较好地保存。

  • 图12 巴楚地区永安坝剖面小层内锶含量分布与颗粒灰岩埋藏云化过程示意图

  • Fig.12 The model of burial dolomitizing font showing the transition of grainstone to coarse crystalline dolomite to medium crystalline dolomite and corresponding Sr contents of Yonganba outcrop in Bachu area

  • 在晚奥陶世—志留纪的浅埋藏期,随着埋深的增加,温度升高,在缝合线形成期间,灰岩经历较强的稳定化转变,转变为以低镁方解石为主,导致颗粒灰岩孔隙丢失严重。在构造运动的驱动下,地层流体开始发生运移。Hardie(1987)指出,富含Ca的流体在温度高于60℃时可以进行白云石化作用,使大多数天然地下水具有这一特征。根据Lind(1993)Fabricius(2000)的研究,与缝合线共同形成的白云石表明埋深至少达到600 m,他形、浑浊的晶面指示埋藏温度超过60℃。埋藏史表明,蓬莱坝组白云岩在晚奥陶世—志留纪埋深600 m,泥盆纪埋深1000 m,对应温度高达60℃(图2),即蓬莱坝组内部地层流体即具有云化潜力。此时,颗粒灰岩的矿物成分较为稳定,孔隙度保存较好。随后,蓬莱坝组在逆冲作用下经历了区域性抬升,在构造运动驱动的情况下,可能使得地层流体发生运移,埋藏云化流体首先自准同生白云岩层中运移,然后逐渐扩散进入周围的灰岩中,造成灰岩的埋藏云化(图13b),或对准同生白云岩造成重结晶作用。原岩孔隙的保存、区域流体运移和相对较高的温度使得白云化作用普遍存在。

  • 岩石学和地球化学特征揭示,这一过程的发生始自细中晶白云岩(原颗粒云岩)进而向周围扩散,导致中粗晶白云岩形成,残留有胶结致密的颗粒灰岩。根据岩石类型厚度统计,研究剖面蓬莱坝组白云岩段中细中晶白云岩占比约50%,中粗晶白云岩约30%,灰岩占近20%,且细中晶白云岩和中粗晶白云岩多为互层发育。因此,可以认为受高频层序旋回控制的准同生云化作用改造的颗粒云岩的发育对于规模白云岩的形成至关重要。正是由于地层中层厚不大,发育大量孔隙的颗粒云岩构成流体运移通道,使得在埋藏期云化流体逐渐向外侧灰岩渗透扩散,大大地提升了白云岩所占比例,从而形成了规模白云岩。总之,根据不同类型白云岩发育占比可知,海平面波动下大量叠置发育的准同生白云岩是规模埋藏白云岩形成的关键,特别是有利于基质孔发育的渗透回流型准同生白云岩,在高频层序格架下的发育占比越高、越频繁,越有利于埋藏云化的顺层渗透扩散,进而提升白云岩占比(图13b),更有利于形成大规模白云岩。

  • 图13 巴楚地区永安坝剖面准同生叠加埋藏白云石化作用发生过程与富镁流体运移机制模式图(剖面位置见图1)

  • Fig.13 The model of two stages of dolomitization processes and dolomitizing fluid migration of Yonganba outcrop in Bachu area (outcrop location shown in Fig.1)

  • (a)—准同生期白云岩分布与富镁云化流体运移机制;(b)—埋藏期白云岩分布与富镁云化流体运移机制

  • (a)—distribution of penecontemporaneous dolomite and mechanism of magnesium-rich dolomitized fluid migration;(b)—distribution of dolomite during burial and mechanism of magnesium-rich dolomitized fluid migration

  • 6 结论

  • (1)蓬莱坝组不同类型白云岩的镁同位素分布虽有重叠,但是差异较明显,藻纹层白云岩3个样品的镁同位素为-2.34‰~-2.26‰;细中晶残余颗粒白云岩的镁同位素分布范围较广,为-2.24‰~-2.02‰,平均为-2.14‰;粗晶白云岩的镁同位素除一个样品为-1.89‰,其余样品集中在-2.24‰~-2.13‰,平均值为-2.21‰;蓬莱坝组灰岩镁同位素为-3.63‰,较白云岩明显更偏负。

  • (2)在岩石学特征基础上,镁同位素与氧同位素、锶同位素和锶元素含量在高频旋回中表现出规律性的旋回变化,揭示出渗透回流模式、蒸发泵模式和埋藏云化叠加改造模式三种云化机制。

  • (3)厚层白云岩是由多期白云石化作用叠加而成,既有层内云化流体也受源外云化流体影响,受沉积相和构造埋藏演化史共同控制,海平面波动下大量叠置发育的准同生白云岩是规模埋藏白云岩形成的关键。

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    • 黄文辉, 杨敏, 于炳松, 樊太亮, 初广震, 万欢, 朱井泉, 吴仕强, 王旭. 2006. 塔中地区寒武系-奥陶系碳酸盐岩Sr元素和Sr同位素特征. 地球科学, 31(6): 839~845.

    • 柯珊, 刘盛遨, 李王晔, 杨蔚, 滕方振. 2011. 镁同位素地球化学研究新进展及其应用. 岩石学报, 27(2): 383~397.

    • 梅冥相. 2012. 从3个科学理念简论沉积学中的“白云岩问题”云岩问题. 古地理学报, 14(1): 1~12.

    • 甯濛, 黄康俊, 沈冰. 2018. 镁同位素在“白云岩问题”研究中的应用及进展. 岩石学报, 34(12): 3690~3708.

    • 乔占峰, 沈安江, 郑剑锋, 胡杰, 吴兴宁, 陆俊明. 2012. 塔里木盆地下奥陶统白云岩类型及其成因. 古地理学报, 14(1): 21~32.

    • 乔占峰, 张哨楠, 沈安江, 胡安平, 梁峰, 罗宪婴, 佘敏, 吕学菊. 2020. 基于激光U-Pb定年的埋藏白云岩形成过程——以塔里木盆地永安坝剖面下奥陶统蓬莱坝组为例. 岩石学报, 36(11): 3493~3509.

    • 邵龙义, 何宏, 彭苏萍. 2002. 塔里木盆地巴楚隆起寒武系及奥陶系白云岩类型及形成机理. 古地理学报, 4(2): 19~28.

    • 熊冉, 张天付, 乔占峰, 贺训云, 王慧. 2019. 塔里木盆地奥陶系蓬莱坝组碳酸盐岩缓坡沉积特征及油气勘探意义. 沉积与特提斯地质, 39(1): 42~49.

    • 杨威, 王清华, 刘效曾. 2000. 塔里木盆地和田河气田下奥陶统白云岩成因. 沉积学报, 18(4): 544~547.

    • 张臣, 郑多明, 李江海. 2001. 柯坪断隆古生代的构造属性及其演化特征. 石油与天然气地质, 22(4): 314~318.

    • 赵文智, 沈安江, 胡素云, 潘文庆, 郑剑锋, 乔占峰. 2012. 塔里木盆地寒武-奥陶系白云岩储层类型与分布特征. 岩石学报, 28(3): 758~768.

    • 郑剑锋, 沈安江, 乔占峰, 倪新峰. 2013. 塔里木盆地下奥陶统蓬莱坝组白云岩成因及储层主控因素分析——以巴楚大班塔格剖面为例. 岩石学报, 29(9): 267~276.

    • 朱井泉, 吴仕强, 王国学, 胡文瑄. 2008. 塔里木盆地寒武-奥陶系主要白云岩类型及孔隙发育特征. 地学前缘, 15(2): 67~79.

    • 朱莲芳, 马宝林. 1991. 塔里木盆地阿克苏-柯坪地区寒武系-奥陶系的沉积环境. 沉积学报, 9(2): 55~62.

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    • 甯濛, 黄康俊, 沈冰. 2018. 镁同位素在“白云岩问题”研究中的应用及进展. 岩石学报, 34(12): 3690~3708.

    • 乔占峰, 沈安江, 郑剑锋, 胡杰, 吴兴宁, 陆俊明. 2012. 塔里木盆地下奥陶统白云岩类型及其成因. 古地理学报, 14(1): 21~32.

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    • 熊冉, 张天付, 乔占峰, 贺训云, 王慧. 2019. 塔里木盆地奥陶系蓬莱坝组碳酸盐岩缓坡沉积特征及油气勘探意义. 沉积与特提斯地质, 39(1): 42~49.

    • 杨威, 王清华, 刘效曾. 2000. 塔里木盆地和田河气田下奥陶统白云岩成因. 沉积学报, 18(4): 544~547.

    • 张臣, 郑多明, 李江海. 2001. 柯坪断隆古生代的构造属性及其演化特征. 石油与天然气地质, 22(4): 314~318.

    • 赵文智, 沈安江, 胡素云, 潘文庆, 郑剑锋, 乔占峰. 2012. 塔里木盆地寒武-奥陶系白云岩储层类型与分布特征. 岩石学报, 28(3): 758~768.

    • 郑剑锋, 沈安江, 乔占峰, 倪新峰. 2013. 塔里木盆地下奥陶统蓬莱坝组白云岩成因及储层主控因素分析——以巴楚大班塔格剖面为例. 岩石学报, 29(9): 267~276.

    • 朱井泉, 吴仕强, 王国学, 胡文瑄. 2008. 塔里木盆地寒武-奥陶系主要白云岩类型及孔隙发育特征. 地学前缘, 15(2): 67~79.

    • 朱莲芳, 马宝林. 1991. 塔里木盆地阿克苏-柯坪地区寒武系-奥陶系的沉积环境. 沉积学报, 9(2): 55~62.