南京大学学报(自然科学), 2020, 56(3): 308-321 doi: 10.13232/j.cnki.jnju.2020.03.002

微生物碳酸盐岩同生⁃早成岩阶段有机质降解示踪:以四川盆地灯影组四段为例

游杰1,2, 胡广,1,2, 张玺华3, 沈安江4,5, 彭瀚霖3, 田兴旺3, 赵东方1,2

1.油气藏地质及开发工程国家重点实验室,西南石油大学,成都,610500

2.中国石油天然气集团有限公司碳酸盐岩储层重点实验室,西南石油大学研究分室,成都,610500

3.中国石油西南油气田公司勘探开发研究院,成都,610051

4.中国石油杭州地质研究院,杭州,310023

5.中国石油天然气集团公司碳酸盐岩储集层重点实验室,杭州,310023

Geochemical tracing of organic matter degradation in microbial carbonates during syngenetic⁃early diagenesis: A case study from the Member IV of Dengying Formation,Sichuan Basin

You Jie1,2, Hu Guang,1,2, Zhang Xihua3, Shen Anjiang4,5, Peng Hanlin3, Tian Xingwang3, Zhao Dongfang1,2

1.State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,610500,China

2.Research Division of Key Laboratory of Carbonate Reservoir,CNPC,Southwest Petroleum University,Chengdu,610500,China

3.Research Institute of Petroleum Exploration and Development,Southwest Oil and Gasfield Company,PetroChina,Chengdu,610051,China

4.Petrochina Hangzhou Research Institute of Geology,Hangzhou,310023,China

5.Key Laboratory of Carbonate Reservoirs,CNPC,Hangzhou,310023,China

通讯作者: E⁃mail:guanghu1198119@163.com

收稿日期: 2020-03-03   网络出版日期: 2020-05-28

基金资助: 国家自然科学基金.  41872155

Received: 2020-03-03   Online: 2020-05-28

摘要

微生物碳酸盐岩中有机质在同生⁃早成岩阶段的降解既可以产生酸性流体对碳酸盐颗粒进行溶解,扩大后期成储流体通道,有利于储层发育;但也可能导致孔隙水处在碱性环境下,形成碳酸盐矿物胶结,阻碍溶蚀流体对储层的改造.因此,同生⁃早成岩期有机质降解对微生物岩储层储集空间的形成有重要影响,但研究薄弱.以四川盆地北部地区上震旦统灯影组四段(灯四段)微生物碳酸盐岩为例,综合岩石学和原位微区地球化学分析(LA⁃ICP⁃MS),开展了这一降解过程的地球化学示踪研究.结果显示,当微生物碳酸盐岩中的有机质处于有氧降解时,微亮晶和亮晶组构均具有Ce负异常;当亮晶组构Ce元素转变为正异常时,表明有机质进入厌氧降解阶段.此外,微生物岩亮晶组构中Cr含量高于微亮晶组构,可以作为有机质降解经过了硝酸盐还原过程的识别标志.如果有机质被Fe⁃Mn氧化物氧化降解,则会造成微生物岩微亮晶组构中Fe含量高于亮晶组构.随着成岩环境的还原状态进一步加强,有机质降解进入硫酸盐还原阶段,将导致微生物岩中亮晶组构相对于微亮晶组构富集Cu,Mo元素.因此,Ce,Cr,Fe,Mo,Cu等元素在微生物岩不同岩石组构中的变化可以有效识别微生物岩同生⁃早成岩阶段有机质降解的成岩环境并示踪有机质降解过程.

关键词: 有机质降解 ; 地化特征 ; 微生物碳酸盐岩 ; 灯四段 ; 川北地区

Abstract

The degradation of organic matter in microbial carbonates during early diagenesis not only can produce acidic fluids to dissolve carbonate grains,which may amplify the channels for later dissolution and be beneficial to the development of reservoirs,but also can result in alkaline pore water that precipitates carbonate cements which may hinder the development of reservoir. Therefore,the degradation of organic matter during syngenetic⁃early diagenesis stage has important impacts on the development of reservoir in microbial carbonates. However,the characteristics and recognization about degradation of organic matter in microbial carbonates have not yet been studied. In this study,we conducted petrological analyses and in situ geochemical for microbial carbonates from the Member IV of Dengying Formation,Northern Sichuan Basin to characterize organic matter degradation in microbial carbonates. Results show that when the organic matter in the microbial carbonates is degraded by aerobic respiration,both the microspar and sparite components have negative Ce anomalies,whereas the positive Ce anomaly of sparite component indicates that the degradation of organic matter is under an anaerobic environment. If organic matters in microbial carbonate are oxygenated by nitrate reduction,the Cr concentration of microspar component is lower than that in sparite component. If the organic matter is degraded by Fe⁃Mn oxides reduction,the Fe concentration in microspar component is higher than that of sparite component. With the reduction state of diagenetic environment further strengthening,the organic matter may be further degraded by sulfate reduction,which leads to the higher Cu and Mo concentrations in the sparite component compared with the microspar component in microbial carbonates. As a consequence,the variation of elements Ce,Cr,Fe,Mo,Cu in components of microbial carbonates could reflect the diagenetic environment,and also can trace the process of the organic matter degradation effectively.

Keywords: organic matter degradation ; geochemical characteristics ; microbial carbonates ; Member IV of Dengying Formation ; Northern Sichuan Basin

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游杰, 胡广, 张玺华, 沈安江, 彭瀚霖, 田兴旺, 赵东方. 微生物碳酸盐岩同生⁃早成岩阶段有机质降解示踪:以四川盆地灯影组四段为例. 南京大学学报(自然科学)[J], 2020, 56(3): 308-321 doi:10.13232/j.cnki.jnju.2020.03.002

You Jie, Hu Guang, Zhang Xihua, Shen Anjiang, Peng Hanlin, Tian Xingwang, Zhao Dongfang. Geochemical tracing of organic matter degradation in microbial carbonates during syngenetic⁃early diagenesis: A case study from the Member IV of Dengying Formation,Sichuan Basin. Journal of nanjing University[J], 2020, 56(3): 308-321 doi:10.13232/j.cnki.jnju.2020.03.002

近年来,随着全球油气勘探的突破,微生物碳酸盐岩作为一种重要的油气储层,受到国内外广大学者的关注[1,2,3,4].前人针对微生物碳酸盐岩储层开展了大量工作,主要集中在沉积相、岩类学、储层特征及储层成因等方面[2,5,6,7,8,9].目前主流观点认为,岩溶改造是微生物碳酸盐岩储层形成的关键过程,这是因为微生物碳酸盐岩主要发育在潮坪环境[10,11],在该环境沉积的岩石经常因相对海平面的变化而发生岩溶作用,使得岩溶改造普遍发生[12,13,14].但是,越来越多的研究实例证实,微生物碳酸盐岩储层的形成除了与岩溶作用有关外,还与自身是否存在先期的岩溶通道关系密切[15,16].

微生物岩中同生⁃早成岩阶段有机质降解可能是形成先期岩溶通道的重要方式.微生物碳酸盐岩是微生物诱导、捕获和粘结等过程形成的碳酸盐岩[17],因此现代微生物碳酸盐沉积物中一般富有机质.但随成岩作用的进行,有机质发生降解、矿化,有机碳含量逐渐减少[18].在这些降解过程中既可以产生酸性流体对周围的碳酸盐颗粒进行溶蚀,也可以形成碱性环境产生碳酸盐矿物胶结[19,20].溶蚀作用产生的微小孔隙可能为后续岩溶流体提供通道,加速岩溶改造过程,促进储集空间的形成;而胶结作用则会减弱后期岩溶效果.可见,微生物岩中同生⁃早成岩阶段有机质降解的成储效应是相当复杂的,需要深入研究.

有机质在同生⁃早成岩期降解过程中发生了一系列复杂的生物化学反应[21,22,23,24],主要包括有氧降解、硝酸盐还原、铁锰等金属氧化物还原以及硫酸盐还原等降解过程[21,25,26].其中,有氧降解、硝酸盐还原过程会导致碳酸盐矿物的溶蚀,而Fe⁃Mn氧化物还原和硫酸盐还原过程会形成碳酸盐矿物沉淀[19].可以预见微生物碳酸盐岩中有机质所经历的不同降解过程和路径将为微生物碳酸盐岩储层形成带来不同的效果,因此,明确地质历史时期微生物碳酸盐岩中有机质到底经历哪些降解过程以及对这些过程的示踪是解析其成储效应的关键.

然而,纵观当前研究现状,相关工作多是针对现代海洋沉积物中有机质降解过程进行研究,对地质历史时期的微生物碳酸盐岩还缺乏相应的实例研究.四川盆地灯影组四段微生物碳酸盐岩是良好的油气储层,微生物碳酸盐岩结构类型丰富,储层孔隙类型多样、差异性大[27,28],为研究微生物碳酸盐岩有机质降解提供良好材料.本文选择四川盆地北部(川北)地区胡家坝剖面和许家嘴剖面灯四段微生物碳酸盐岩,开展微生物岩中同生⁃早成岩阶段有机质降解的特征及示踪研究,期望研究结果可以为有机质降解的成储效应研究提供参考依据,以进一步丰富微生物碳酸盐岩的成储理论.

1 研究区地质背景

研究剖面位于四川盆地北部地区陕西省汉中市宁强县胡家坝镇,是四川盆地和秦岭造山带的过渡区域.晚震旦世灯影期,四川盆地主要为碳酸盐岩台地沉积,盆地内部水体较浅,发育潮坪、泻湖、台内滩等亚相[29,30,31].根据岩性和岩石结构特征,四川盆地灯影组自下而上可划分为四个层段[32,33](图1a).灯一段岩性主要为泥微晶白云岩,微生物碳酸盐岩不发育;灯二段为富含微生物的白云岩段,除了泥⁃粉晶白云岩外,藻砂屑云岩、藻凝块云岩、核形石等微生物白云岩普遍发育,还具有“葡萄花边”状白云岩,是四川盆地灯二段的典型标志;灯三段为一套砂泥岩为主的碎屑岩沉积,厚度几十厘米到几十米不等,在全盆地广泛分布;灯四段主要为含硅质的泥微晶白云岩、叠层石和凝块石云岩[15,27].

图1

图1   剖面位置及样品

(a)(b)川北地区灯四段沉积期岩相古地理(修改自邹才能等[32])及剖面位置;(c)研究剖面灯四段岩性结构图及取样位置

Fig.1   Section position and samples


研究区在灯四段沉积期岩相古地理属台缘微生物丘滩相沉积(图1b),微生物碳酸盐岩发育[34],岩石类型以泥⁃粉晶云岩、藻云岩、砂屑云岩和藻砂屑云岩为主[35,36].灯四段沉积末期,受桐湾运动II幕的影响,整个四川盆地相对海平面下降,灯四段地层暴露地表遭受剥蚀[37,38],导致川北地区灯四段顶部与上覆宽川铺组地层呈平行不整合接触.

2 样品与方法

本次研究在胡家坝剖面和许家嘴剖面灯四段微生物碳酸盐岩发育的层段共采集新鲜样品53件(图1c),挑选38件典型微生物岩样品磨制铸体薄片.在详细的岩石学分析基础上,对微生物碳酸盐岩不同组构进行了原位微区地球化学分析,结合前人关于现代微生物岩中有机质降解的研究成果,对灯四段微生物岩同生⁃早成岩阶段有机质降解路径进行示踪.

微生物岩样品的微观结构特征分析在中国石油天然气集团有限公司碳酸盐岩储层重点实验室西南石油大学研究分室完成,仪器型号为Leica 450C偏光显微镜.

在详细的岩石学分析基础之上,分别挑选三件晚成岩作用较弱的微生物碳酸盐岩样品开展微区原位地球化学分析.所选的三件典型样品各磨制激光薄片一张,对三类微区岩石组构(即微生物组构、微亮晶组构和亮晶组构)进行原位激光剥蚀等离子质谱分析(LA⁃CP⁃MS).微生物组构是由微生物、胞外聚合物及最早沉淀的细粒碳酸盐矿物(晶粒<1 μm)组成的泥晶沉积,具有较高的有机质含量(同生⁃早成岩期具有较强的自发荧光[39]);亮晶组构为最早期形成的白云石胶结(晶粒<30 μm),其晶粒明显较后期大气淡水胶结小,能够反映早期孔隙水的化学性质;而微亮晶组构则是介于微生物组构和亮晶组构之间的过渡组构(图2).

图2

图2   微生物碳酸盐岩中的微区组构

Fig.2   Specific components of microbial carbonates


ICP⁃MS型号为Agilent 7700e,激光束斑为44 μm,频率为5 Hz,详细的仪器参数和分析流程见Zong et al[40].分析测试采用玻璃标准物质BIR⁃1G,BCR⁃2G和BHVO⁃2G进行多外标无内标校正[41].本次分析的每个时间分辨分析数据包括大约20~30 s的空白信号和50 s样品信号.对分析数据的离线处理采用软件ICPMSDataCal完成[41].LA⁃ICP⁃MS分析测试在武汉上谱分析科技有限责任公司完成.

3 灯四段微生物碳酸盐岩类型及沉积环境

通过野外露头和镜下薄片观察,在胡家坝和许家嘴剖面灯四段共识别出两种典型的微生物碳酸盐岩,分别为凝块云岩和叠层云岩.

3.1 凝块云岩

凝块云岩在研究区灯四段中部和上部较发育(图1c),通常为块状.凝块云岩富含凝块结构,显微镜下表现为暗色且形态不规则的泥晶结构,个别凝块具有空腔,被亮晶白云石充填(图3a).凝块云岩形态上可呈分支格架状(图3b)、分散斑块状(图3c)和密集丛状(图3d)三种形态,而凝块结构可以呈现为边缘清晰状和弥散状两种形式(图3b和图3c).凝块结构大小一般在0.2~5 mm不等.

图3

图3   灯影组四段微生物碳酸盐岩特征

(a)凝块云岩宏观照,可见格架状凝块结构,灯四段,许家嘴剖面;(b)格架状凝块岩,格架间孔隙被二期胶结物充填,第一期为纤状白云石胶结,第二期为自形程度较高的粒状白云石;(c)分散斑块状凝块岩,单个凝块大小介于0.2~1.5 mm,凝块结构边界呈弥散状;(d)密集丛状凝块岩,凝块结构较小,分布较为密集;(e)分散状凝块岩,凝块空腔内见泥微晶沉积物充填在凝块结构和亮晶白云石之间;(f)丘状叠层石宏观照,灯四段,胡家坝剖面;(g)丘状叠层石微观特征,纹层呈波状起伏,亮纹层厚度(约为0.5 mm)较暗纹层(约0.2 mm)大;(h)具平直纹层的叠层石,灯四段,胡家坝剖面;(i)平直状叠层石,纹层较为平直,纹层横向连续

Fig.3   The lithology of microbial carbonates, Member IV of Dengying Formation


凝块结构的形态、大小可反映凝块岩的形成环境[42,43].格架状结构具有一定抗浪能力,灯四段格架状凝块岩通常具有较大的凝块格架,且部分凝块呈断续状(图3b),因此推测格架状凝块岩在生长过程中受到波浪扰动作用,可能形成于水动力较强的环境下,沉积环境为潮间带下部⁃潮下带的上部.在分散状凝块岩中,凝块结构相对较小,分布较为分散(图3c),表明其形成于安静的水体环境;加之缺乏暴露标志(如鸟眼孔、泥屑等),因此推测分散状凝块岩形成于潮下带下部.

3.2 叠层云岩

研究区叠层云石在灯四段广泛发育(图1).叠层云岩在宏观上具有纹层状结构,由暗色纹层和灰白色亮纹层交替构成.按照纹层的形态可分为丘状纹层(图3f)和平直状纹层(图3h).显微镜下暗色纹层由富含微生物的泥微晶白云石组成,厚度约为0.1~0.2 mm;亮纹层为微⁃粉晶白云石组成,厚度一般较暗纹层大,为0.2~1 mm不等(图3g和图3i).平直状纹层横向连续性较好,波状纹层常呈断续状.亮纹层内部常发育窗格状孔隙,被晶粒较大的粒状白云石部分⁃完全充填,偶见粒状白云石胶结被硅化(图3g).

纹层的形态可指示叠层石沉积时的水动力条件[42,43].丘状叠层石具有波状起伏的纹层,通常指示微生物席在沉积时期受到波浪的扰动,镜下可见纹层的横向连续性较差,常呈断续状分布(图3g),因此推测丘状叠层石通常形成在水动力稍强的潮间带下部.具平直状纹层的叠层石中,平直光滑的纹层指示其沉积时水体较为安静,纹层连续;纹层粒度较细,多以泥微晶为主(图3i),缺乏粗颗粒沉积亦说明沉积时水动力较弱,因此推测平直状纹层的叠层石可能形成在相对低能的潮间带上部环境.

4 微生物碳酸盐岩同生⁃早成岩期成岩环境及有机质降解过程地球化学示踪

微生物碳酸盐岩中有机质同生⁃早成岩阶段降解实质上是微生物利用不同的电子受体代谢有机质的过程.微生物碳酸盐岩成岩过程中,表层沉积物通常处在有氧环境下[44,45],有机质降解以有氧降解过程为主,随着深度的增加氧气逐渐被消耗,有机质转而利用其他氧化剂(NO3-,MnO2/Fe2O3,SO42-等),按氧化还原电势由大到小的顺序进行降解.从沉积物表面往下依次为有氧降解带、硝酸盐还原带、Fe⁃Mn等金属氧化物还原带、硫酸盐还原带等[21,46,47].在不同的有机质降解带中,由于有机质降解的路径不同,主量和微量元素在岩石微观组构中存在明显差异[48,49].其中微量元素是示踪有机质降解过程的重要工具[50,51,52,53],尤其是Ce,Cr,Fe,Cu,Mo等元素,与有机质同生⁃早成岩期降解过程密切相关,且不易受后期成岩作用影响而发生迁移,因而能较好地对有机质降解阶段进行示踪[54,55,56,57].本次研究针对所选典型微生物碳酸盐岩(HJB⁃K16,XJZ⁃K6和XJZ⁃K10)的原位微区测试结果见表1图4.

表1   灯四段微生物碳酸盐岩微区组构主量、微量元素特征 (×10-6)

Table 1  Major and trace elements concentrations of specific components in microbial carbonates

样品编号HJB⁃K16XJZ⁃K6XJZ⁃K10
组别第一组第二组第三组第四组
测试点号HJB⁃K16⁃01HJB⁃K16⁃02HJB⁃K16⁃03HJB⁃K16⁃04HJB⁃K16⁃05HJB⁃K16⁃06XJZ⁃K6⁃01XJZ⁃K6⁃02XJZ⁃K6⁃03XJZ⁃K10⁃01XJZ⁃K10⁃02XJZ⁃K10⁃03
微区组构微生物组构微亮晶组构亮晶组构微生物组构微亮晶组构亮晶组构微生物组构微亮晶组构亮晶组构微生物组构微亮晶组构亮晶组构
MgCO3 (wt%)43.6243.2943.0343.1142.2342.5742.5739.8740.3242.9042.7142.58
CaCO3 (wt%)55.8756.2356.4956.3256.8456.9156.1055.3655.1954.9255.8756.02
Cr0.710.640.081.031.271.321.260.651.062.130.330.11
Mn72.2451.34101.0632.8821.69176.24175.72142.62175.20227.11141.03129.06
Fe216.88219.00217.11389.27197.78205.86230.03205.76184.581520.95272.32289.77
Cu0.070.130.070.750.18/1.610.320.047.240.310.37
Mo/0.03/0.120.06/0.07////0.06
Sr31.1235.9831.2231.6233.8524.3053.2339.3330.4943.5831.6327.67
La0.00250.00230.00250.00210.00480.00130.00410.01810.01140.00290.00120.0003
Ce0.00170.00150.00130.00200.00260.00160.00480.01860.01650.00210.00090.0003
Pr0.00250.00140.00080.00280.00570.00150.00740.02730.02080.00420.00110.0002
Nd0.00150.00170.00170.00290.00440.00030.00780.03060.02360.0015//
Sm0.00210.00400.0079/0.00660.00480.00920.03780.01520.0084//
Eu/0.0075/0.00180.0162/0.00570.06040.02710.00690.00280.0053
Gd//0.00330.0066/0.00530.00240.03660.04780.0124/0.0024
Tb//0.00540.00360.00390.00440.00820.02610.01180.01510.00610.0039
Dy/0.00610.00240.00490.00230.00150.01520.04580.01320.0013//
Y0.00300.00410.00380.00230.00490.00680.02370.04120.02910.01220.00290.0004
Ho0.00450.0029/0.00150.00630.00700.00820.03220.01850.01820.00160.0016
Er0.00560.0029/0.00880.0032/0.02150.02570.00790.00410.00160.0031
Tm0.00550.0031/0.0031/0.01870.01410.00340.00340.0259/0.0033
Yb-0.0020/0.00610.00440.00980.01160.00230.01320.0057--
Lu0.00590.0028////0.00310.0094/0.00390.0032/
ΣREE+Y0.4260.4650.4380.5290.8180.4871.7665.3554.0020.8810.2200.080
(Nd/Yb)SN>10.84>10.470.980.030.6813.561.790.26>1>1
Ce/Ce*0.690.780.780.830.501.150.840.821.030.600.771.39

“/”代表元素含量低于检测限

新窗口打开| 下载CSV


图4

图4   灯四段微生物碳酸盐岩微区组构地球化学特征

(a)(d)(g)(j)分别为样品HJB⁃K16第一组和第二组数据,XJZ⁃K6,XJZ⁃K10原位微区测试位置;(b)(e)(h)(k)分别为对应测试区域的稀土PAAS标准化曲线;(c)(f)(i)(l)为对应样品原位微区元素的相对含量

Fig.4   Geochemical characteristics of specific components in microbial carbonates,Member IV of Dengying Formation


4.1 有氧降解过程

在正常氧化海水中沉积的微生物岩,因海水处于氧化环境,Ce元素主要以CeO2的形式存在而从海水中分离出来[58,59],导致从海水中形成的微生物组构通常具有Ce负异常.微生物岩沉积后在氧化⁃还原界面之上,有机质降解途径为有氧降解,此时孔隙水仍然处于氧化环境,且孔隙水与海水交换相对通畅,因此从孔隙水中沉淀下来的碳酸盐矿物一般具有与海水相似的Ce负异常.但当微生物岩处于氧化⁃还原界面之下时,孔隙水处于弱还原到还原状态,有机质降解从有氧降解转变为厌氧降解,此时孔隙水中的Ce以Ce3+的形式存在并进入从孔隙水中沉淀的碳酸盐矿物[59],这导致微生物岩中早期沉淀的亮晶组构具有Ce正异常.

在本次分析的三件样品中,微生物组构、微亮晶组构都具有Ce的负异常(Ce/Ce*<1,表1),指示其原始沉积处在氧化的海水环境;样品HJB⁃K16第一组数据(HJB⁃K16⁃01~03)显示,亮晶组构(HJB⁃K16⁃03)具有Ce的负异常(Ce/Ce*=0.78,表1,图4b),指示其形成于含氧的孔隙水中,该环境下有机质降解以有氧降解方式进行;HJB⁃K16的第二组数据(HJB⁃K16⁃04~06)、XJZ⁃K6、XJZ⁃K10样品中,亮晶组构均具有Ce正异常(Ce/Ce*>1,表1),指示对应的成岩环境为相对缺氧的环境,有机质已经过有氧降解阶段,开始厌氧降解过程.

4.2 硝酸盐还原降解过程

当微生物岩进入到硝酸盐还原带中,由于NO3-还原成N2的氧化还原电势高于CrO42-还原成Cr3+,所以有机质氧化降解优先利用NO3-作电子受体,然后再利用CrO42-作为氧化剂进行氧化降解[53].有机质在利用CrO42-作为氧化剂进行降解的过程中,可将孔隙水中的CrO42-还原成Cr3+,Cr3+同OH-结合成Cr(OH)3沉淀[55](图5),从而导致孔隙水中沉淀的亮晶组构Cr含量高于微亮晶组构.

图5

图5   有机质降解路径、元素迁移过程、氧化还原电势以及各降解路径的成孔示意图

(a)有机质降解路径及元素迁移过程(修改自Widdicombe et al[25]);(b)有机质降解过程所利用电子受体的氧化还原电势

(据Piper[55],Madigan et al[26]);(c)微生物岩在各个有机质降解阶段岩石孔隙的变化

Fig.5   Organic matter degradation pathways, mobilization of elements, redox potential and the changes in pore contents during the degradation of organic matter


在分析的三件样品中,HJB⁃K16样品第二组数据(HJB⁃K16⁃04~06)显示亮晶组构中Cr元素含量为1.33×10-6,略微高于微亮晶组构中Cr元素含量(1.27×10-6)(表1图4f),该组数据指示样品HJB⁃K16部分有机质进行了硝酸盐还原降解过程;而第一组数据(HJB⁃K16⁃01~03)指示HJB⁃K16部分有机质还处在有氧降解阶段,因此推测HJB⁃K16号样品有机质降解整体处在有氧降解⁃硝酸盐还原阶段.而在样品XJZ⁃K6中,亮晶组构中Cr元素含量(1.06×10-6)明显大于微亮晶组构(0.65×10-6)(表1图4i),因此推测XJZ⁃K6号样品有机质降解已经完全经历了硝酸盐还原过程.

4.3 Fe⁃Mn氧化物还原降解过程

在Fe⁃Mn氧化物还原带中,有机质将微生物岩中不可溶的氧化态Fe(III),Mn(IV)还原为Fe2+,Mn2+并从沉积物迁移到孔隙水中(图5),导致微生物沉积物中Fe,Mn含量的降低[58,59,60,61].因此,微生物碳酸盐岩有机质降解如果进行了Fe⁃Mn氧化物还原过程,被还原成二价的Fe元素将从微生物组构向微亮晶组构和孔隙水中依次扩散,导致Fe元素在亮晶组构中的含量要小于微亮晶组构.

HJB⁃K16号样品第二组数据中,微亮晶组构中的Fe元素含量(197.8×10-6)略低于亮晶组构(205.9×10-6),进一步佐证了其有机质降解没有超过硝酸盐还原阶段(尚未进行Fe⁃Mn氧化物还原过程).而样品XJZ⁃K6中微亮晶组构Fe含量(205.8×10-6)高于亮晶组构(184.6×10-6)(表1图4i),指示其有机质降解经历了Fe的氧化物还原过程.

4.4 硫酸盐还原降解过程

微生物岩中有机质在经历有氧降解带、硝酸盐还原带和Fe⁃Mn氧化物还原带降解之后如果还有剩余,那么剩余的有机质可在硫酸盐还原带进一步降解[62,63].有机质在硫酸盐还原过程中降解会产生H2S迁移到孔隙水中,与Cu2+,MoO42-反应形成CuS,MoS2等不可溶的金属硫化物[55,64](图5),导致微生物岩中亮晶组构相对于微亮晶组构富集Cu和Mo元素.

实验结果显示,样品XJZ⁃K6的亮晶组构Cu含量(0.04×10-6)低于微亮晶组构(0.32×10-6),Mo元素在微亮晶、亮晶组构中含量均低于检测限,因此根据Cu元素在微区组构的变化,推测当时孔隙水体中不存在游离的H2S,指示其有机质降解还未开始硫酸盐还原过程.而样品XJZ⁃K10亮晶组构的Cu,Mo含量(分别为0.37×10-6和0.06×10-6)均高于微亮晶组构(Cu含量为0.31×10-6,Mo含量低于检测限)(表1图4l),揭示早期形成的亮晶组构可能从硫化的孔隙水中沉淀,故推测该样品有机质降解经历了硫酸盐还原阶段,并且有机质在硫酸盐还原过程中降解充分,产生了充足的H2S,在与孔隙水中Cu2+,MoO42-反应后仍有剩余,继续与有机质Fe⁃Mn氧化物还原过程中产生的Fe2+结合生成FeS,导致亮晶组构中Fe含量(289.8×10-6)高于微亮晶组构(272.3×10-6)(图4l).

综上,本次分析的三件样品中,HJB⁃K16有机质降解处在有氧降解⁃硝酸盐还原的过渡阶段,XJZ⁃K6有机质降解位于Fe⁃Mn氧化物还原阶段,而XJZ⁃K10有机质降解进行到了硫酸盐还原阶段.前人研究表明,在有机质的系列降解过程中,有氧降解、硝酸盐还原过程会造成碳酸盐矿物的溶蚀,Fe⁃Mn氧化物还原阶段将产生大量CaCO3矿物导致岩石胶结[65],而硫酸盐还原过程亦会产生溶蚀增加岩石孔隙(该过程反应简式如式(1),每降解两个单位量有机质,将会产生一个单位量的CaCO3沉淀,假定单位量有机质与CaCO3矿物等体积,则该过程有机质降解的成孔比例为2∶1[19]),削弱有机质Fe⁃Mn氧化物还原降解阶段对岩石产生的胶结.最终有机质降解路径在岩石孔隙发育程度上的反映为:有氧降解⁃硝酸盐还原过程>硫酸盐还原过程>Fe⁃Mn氧化物还原过程(图5).本次研究的三件样品的铸体薄片显示,样品HJB⁃K16孔隙最好,有机质降解产生的孔隙多分布在凝块结构内部,被后期形成的粒状白云石胶结充填(图6a和图6b),XJZ⁃K6孔隙不发育(图6c),而XJZ⁃K10孔隙发育程度介于HJB⁃K16和XJZ⁃K6之间(图6d).观察到的孔隙发育程度与示踪的有机质降解路径存在较好的匹配关系(图6),表明利用微生物岩中不同组构内Ce,Cr,Fe,Cu,Mo等元素能有效地对研究区灯四段微生物碳酸盐岩同生⁃早成岩期成岩环境及有机质降解路径进行示踪.

图6

图6   不同有机质降解阶段微生物碳酸盐岩孔隙发育特征

(a)(b) HJB-K16,有机质处在有氧降解⁃硝酸盐还原过程,导致岩石中溶蚀孔隙发育,有机质降解产生的孔隙多发育在凝块结构内部,被后期成岩过程中白云石胶结充填;(c) XJZ⁃K6,有机质的Fe⁃Mn氧化物还原降解过程导致岩石胶结紧密;(d) XJZ⁃K10,有机质降解处在硫酸盐还原阶段,孔隙介于有机质降解处在有氧降解⁃硝酸盐还原阶段和Fe⁃Mn氧化物还原阶段的样品之间

Fig.6   The Pores in microbial carbonates with different pathways of orgnic matter degradation


2CH2O+SO+42-OH-+Ca2+CaCO3+CO2+2H2O+HS-

5 结 论

微生物碳酸盐岩不同组构(微生物组构、微亮晶组构和亮晶组构)中的Ce,Cr,Fe,Mo,Cu等元素含量变化能够有效地反映同生⁃早成岩阶段有机质降解的成岩环境,并对微生物岩中有机质降解路径进行较好的示踪:

(1)Ce元素是判断有机质降解是否经历有氧降解的重要指标.在有氧降解带中,孔隙水处在氧化条件下,微生物岩中沉淀于早期孔隙水的亮晶组构具有Ce的负异常;当有机质进入厌氧降解阶段时,亮晶组构Ce元素表现为正异常.

(2)在硝酸盐还原带,有机质降解优先利用NO3-作为氧化剂进行降解,其次才是CrO42-,因此微生物岩亮晶组构中Cr元素含量高于微亮晶组构,可以作为有机质降解经过了硝酸盐还原过程的识别标志.

(3)在Fe⁃Mn氧化物还原阶段,有机质的降解会将铁的氧化物(如Fe2O3)还原为Fe2+扩散到孔隙水中,因此在微生物岩微区组构上表现为微亮晶组构Fe含量高于亮晶组构.

(4)在有机质的硫酸盐还原过程中,孔隙水中SO42-被有机质还原为H2S,与Cu2+,Mo2+结合生成金属硫化物沉淀,导致微生物岩中亮晶组构相对于微亮晶组构富集Cu和Mo元素.

参考文献

宋金民罗平杨式升.

塔里木盆地下寒武统微生物碳酸盐岩储集层特征

石油勘探与开发,201441(4):404-413437.

[本文引用: 1]

Song J MLuo PYang S S,et al.

Reservoirs of Lower Cambrian microbial carbonates,Tarim Basin,NW China

Petroleum Exploration and Development201441(4):404-413437.

[本文引用: 1]

陈娅娜沈安江潘立银.

微生物白云岩储集层特征、成因和分布——以四川盆地震旦系灯影组四段为例

石油勘探与开发,201744(5):704-715.

[本文引用: 2]

Chen Y NShen A JPan L Y,et al.

Features,origin and distribution of microbial dolomite reservoirs:a case study of 4th Member of Sinian Dengying Formation in Sichuan Basin,SW China

Petroleum Exploration and Development201744(5):704-715.

[本文引用: 2]

Rezende M FTonietto S NPope M C.

Three⁃dimensional pore connectivity evaluation in a Holocene and Jurassic microbialite buildup

AAPG Bulletin,201397(11):2085-2101.

[本文引用: 1]

Mancini E AMorgan W AHarris P Met al.

Introduction:AAPG Hedberg Research Conference on Microbial Carbonate Reservoir Characterization

Conference summary and selected papers. AAPG Bulletin,201397(11):1835-1847.

[本文引用: 1]

方少仙侯方浩董兆雄.

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,200321(1):96-105.

[本文引用: 1]

Fang S XHou F HDong Z X.

Non⁃stromatoltite ecologic system cyanobacteria dolostone in Dengying Formation of Upper⁃Sinian

Acta Sedimentologica Sinica200321(1):96-105.

[本文引用: 1]

陈宗清.

四川盆地震旦系灯影组天然气勘探

中国石油勘探,201015(4):1-14.

[本文引用: 1]

Chen Z Q.

Gas exploration in Sinian Dengying Formation,Sichuan Basin

China Petroleum Exploration201015(4):1-14.

[本文引用: 1]

刘家洪杨平汪正江.

黔北震旦系灯影组顶部古风化壳特征及油气意义

中国地质,201239(4):931-938.

[本文引用: 1]

Liu J HYang PWang Z J,et al.

Paleo⁃weathering crust at the top of Sinian Dengying Formation in northern Guizhou and its petroleum exploration significance

Geology in China201239(4):931-938.

[本文引用: 1]

李凌谭秀成曾伟.

四川盆地震旦系灯影组灰泥丘发育特征及储集意义

石油勘探与开发,201340(6):666-673.

[本文引用: 1]

Li LTan X CZeng W,et al.

Development and reservoir significance of mud mounds in Sinian Dengying Formation,Sichuan Basin

Petroleum Exploration and Development201340(6):666-673.

[本文引用: 1]

赵文智沈安江周进高.

礁滩储集层类型、特征、成因及勘探意义——以塔里木和四川盆地为例

石油勘探与开发,201441(3):257-265.

[本文引用: 1]

Zhao W ZShen A JZhou J G,et al.

Types,characteristics,origin and exploration significance of reef⁃shoal reservoirs:a case study of Tarim Basin,NW China and Sichuan Basin,SW China

Petroleum Exploration and Development201441(3):257-265.

[本文引用: 1]

Jahnert R JCollins L B.

Significance of subtidal microbial deposits in Shark Bay,Australia

Marine Geology,2011286(1-4):106-111.

[本文引用: 1]

Harwood C LSumner D Y.

Microbialites of the Neoproterozoic Beck Spring Dolomite,Southern California

Sedimentology,201158(6):1648-1673.

[本文引用: 1]

李朋威罗平宋金民.

微生物碳酸盐岩储层特征与主控因素——以塔里木盆地西北缘上震旦统⁃下寒武统为例

石油学报201536(9):1074-1089.

[本文引用: 1]

Li P WLuo PSongJ Met al.

Characteristics and main controlling factors of microbial carbonate reservoirs:a case study of Upper Sinian⁃Lower Cambrian in the northwestern margin of Tarim Basin

Acta Petrolei Sinica201536(9):1074-1089.

[本文引用: 1]

宋金民刘树根李智武.

四川盆地上震旦统灯影组微生物碳酸盐岩储层特征与主控因素

石油与天然气地质,201738(4):741-752.

[本文引用: 1]

Song J MLiu S GLi Z W,et al.

Characteristics and controlling factors of microbial carbonate reservoirs in the Upper Sinian Dengying Formation in the Sichuan Basin,China

Oil & Gas Geology201738(4):741-752.

[本文引用: 1]

Rezende M FPope M C.

Importance of depositional texture in pore characterization of subsalt microbialite carbonates,offshore Brazil

Geological SocietyLondon,Special Publications2015418193.

[本文引用: 1]

姚根顺郝毅周进高.

四川盆地震旦系灯影组储层储集空间的形成与演化

天然气工业,201434(3):31-37.

[本文引用: 2]

Yao G SHao YZhou J G,et al.

Formation and evolution of reservoir spaces in the Sinian Dengying Fm of the Sichuan Basin

Natural Gas Industry201434(3):31-37.

[本文引用: 2]

沈安江赵文智胡安平.

海相碳酸盐岩储集层发育主控因素

石油勘探与开发,201542(5):545-554.

[本文引用: 1]

Shen A JZhao W ZHu A P,et al.

Major factors controlling the development of marine carbonate reservoirs

Petroleum Exploration and Development201542(5):545-554.

[本文引用: 1]

Riding R.

Microbial carbonates:the geological record of calcified bacterial–algal mats and biofilms

Sedimentology,200047179-214.

[本文引用: 1]

Glunk CDupraz CBraissant Oet al.

Microbially mediated carbonate precipitation in a hypersaline lake,Big Pond (Eleuthera,Bahamas)

Sedimentology,201158(3):720-736.

[本文引用: 1]

Visscher P TStolz J F.

Microbial mats as bioreactors:Populations,processes,and products

Palaeogeography,Palaeoclimatology,Palaeoecology,2005219(1-2):87-100.

[本文引用: 3]

Dupraz CReid R PBraissant Oet al.

Processes of carbonate precipitation in modern microbial mats

Earth⁃Science Reviews,200996(3):141-162.

[本文引用: 1]

Froelich P NKlinkhammer G PBender M Let al.

Early oxidation of organic matter in pelagic sediments of the eastern equatorial Atlantic:suboxic diagenesis

Geochimica et Cosmochimica Acta,197943(7):1075-1090.

[本文引用: 3]

Canfield D E.

Sulfate reduction in deep⁃sea sediments

American Journal of Science,1991291(2):177-188.

[本文引用: 1]

Raiswell RFisher Q J.

Rates of carbonate cementation associated with sulphate reduction in DSDP/ODP sediments:implications for the formation of concretions

Chemical Geology,2004211(1-2):71-85.

[本文引用: 1]

Ingalls A EAller R CLee Cet al.

Organic matter diagenesis in shallow water carbonate sediments

Geochimica et Cosmochimica Acta,200468(21):4363-4379.

[本文引用: 1]

Widdicombe SSpicer J IKitidis V.

Effects of ocean acidification on sediment fauna

∥Gattuso J P,Hansson L J. Ocean acidification. Oxford,UKOxford University Press2011176-191.

[本文引用: 2]

Madigan M TMartinko J MBender K Set al.

Brock biology of microorganisms

The 14th Edition. Upper Saddle RiverNJ,USA:Prentice Hall,201579-89.

[本文引用: 2]

斯春松郝毅周进高.

四川盆地灯影组储层特征及主控因素

成都理工大学学报(自然科学版),201441(3):266-273.

[本文引用: 2]

Si C SHao YZhou J G,et al.

Characteristics and controlling factors of reservoir in Sinian Dengying Formation,Sichuan Basin,China

Journal of Chengdu University of Technology (Science & Technology Edition)201441(3):266-273.

[本文引用: 2]

翟秀芬汪泽成罗平.

四川盆地高石梯东部地区震旦系灯影组微生物白云岩储层特征及成因

天然气地球科学,201728(8):1199-1210.

[本文引用: 1]

Zhai X FWang Z CLuo P,et al.

Characteristics and origin of microbial dolomite reservoirs in Upper Sinian Deingying Formation,eastern Gaoshiti area,Sichuan Basin,SW China

Natural Gas Geoscience201728(8):1199-1210.

[本文引用: 1]

李英强何登发文竹.

四川盆地及邻区晚震旦世古地理与构造——沉积环境演化

古地理学报,201315(2):231-245.

[本文引用: 1]

Li Y QHe D FWen Z.

Palaeogeography and tectonic–depositional environment evolution of the Late Sinian in Sichuan Basin and adjacent areas

Journal of Palaeogeography201315(2):231-245.

[本文引用: 1]

刘树根宋金民罗平.

四川盆地深层微生物碳酸盐岩储层特征及其油气勘探前景

成都理工大学学报(自然科学版),201643(2):129-152.

[本文引用: 1]

Liu S GSong J MLuo P,et al.

Characteristics of microbial carbonate reservoir and its hydrocarbon exploring outlook in the Sichuan Basin,China

Journal of Chengdu University of Technology (Science & Technology Edition)201643(2):129-152.

[本文引用: 1]

周进高张建勇邓红婴.

四川盆地震旦系灯影组岩相古地理与沉积模式

天然气工业,201737(1):24-31.

[本文引用: 1]

Zhou J GZhang J YDeng H Y,et al.

Lithofacies paleogeography and sedimentary model of Sinian Dengying Fm in the Sichuan Basin

Natural Gas Industry201737(1):24-31.

[本文引用: 1]

邹才能杜金虎徐春春.

四川盆地震旦系⁃寒武系特大型气田形成分布、资源潜力及勘探发现

石油勘探与开发,201441(3):278-293.

[本文引用: 2]

Zhou C NDu J HXu C C,et al.

Formation,distribution,resource potential and discovery of the Sinian⁃Cambrian giant gas field,Sichuan Basin,SW China

Petroleum Exploration and Development201441(3):278-293.

[本文引用: 2]

刘静江李伟张宝民.

上扬子地区震旦纪沉积古地理

古地理学报,201517(6):735-753.

[本文引用: 1]

Liu J JLi WZhang B M,et al.

Sedimentary palaeogeography of the Sinian in Upper Yangtze Region

Journal of Palaeogeography201517(6):735-753.

[本文引用: 1]

周慧李伟张宝民.

四川盆地震旦纪末期⁃寒武纪早期台盆的形成与演化

石油学报,201536(3):310-323.

[本文引用: 1]

Zhou HLi WZhang B M,et al.

Formation and evolution of Upper Sinian to Lower Cambrian intraplatformal basin in Sichuan Basin

Acta Petrolei Sinica201536(3):310-323.

[本文引用: 1]

郭旭升胡东风段金宝.

四川盆地北部宁强胡家坝灯影组四段岩石特征及沉积环境分析

石油实验地质,201840(6):749-756.

[本文引用: 1]

Guo X SHu D FDuan J B,et al.

Rock features and sedimentary environment of the fourth member of Dengying Formation in Hujiaba section of Ningqiang,northern Sichuan Basin

Petroleum Geology & Experiment201840(6):749-756.

[本文引用: 1]

王良军.

川北地区灯影组四段优质储层特征及控制因素

岩性油气藏,201931(2):35-45.

[本文引用: 1]

Wang L J.

Characteristics and controlling factors of high⁃quality reservoirs of the fourth member of Dengying Formation in northern Sichuan Basin

Lithologic Reservoirs201931(2):35-45.

[本文引用: 1]

武赛军魏国齐杨威.

四川盆地桐湾运动及其油气地质意义

天然气地球科学,201627(1):60-70.

[本文引用: 1]

Wu S JWei G QYang W,et al.

Tongwan Movement and its geologic significances in Sichuan Basin

Natural Gas Geoscience201627(1):60-70.

[本文引用: 1]

杨雨黄先平张健.

四川盆地寒武系沉积前震旦系顶界岩溶地貌特征及其地质意义

天然气工业,201434(3):38-43.

[本文引用: 1]

Yang YHuang X PZhang J,et al.

Features and geologic significances of the top Sinian karst landform before the Cambrian deposition in the Sichuan Basin

Natural Gas Industry201434(3):38-43.

[本文引用: 1]

Dupraz CVisscher P TBaumgartner L Ket al.

Microbe⁃mineral interactions:early carbonate precipitation in a hypersaline lake (Eleuthera Island,Bahamas)

Sedimentology,200451(4):745-765.

[本文引用: 1]

Zong K QKlemd RYuan Yet al.

The assembly of Rodinia:The correlation of early Neoproterozoic (ca

900 Ma) high⁃grade metamorphism and continental arc formation in the southern Beishan Orogen,southern Central Asian Orogenic Belt (CAOB). Precambrian Research,201729032-48.

[本文引用: 1]

Liu Y SHu Z CGao Set al.

In situ analysis of major and trace elements of anhydrous minerals by LA⁃ICP⁃MS without applying an internal standard

Chemical Geology,2008257(1-2):34-43.

[本文引用: 2]

Stolz J F.

Structure of microbial mat and biofilms

∥Riding R E,Awramik S E. Microbial Sediments. Springer Heidelberg,2000:1-8

[本文引用: 2]

Riding R. Microbialitesstromatolites

and thrombolites

∥Reitner J,Thiel V. Encyclopedia of Geobiology. Springer Heidelberg,2011635-654.

[本文引用: 2]

Stal L Jvan Gemerden HKrumbein W E.

Structure and development of a benthic marine microbial mat

FEMS Microbiology Ecology,198531(2):111-125.

[本文引用: 1]

Vasconcelos CWarthmann RMcKenzie J Aet al.

Lithifying microbial mats in Lagoa Vermelha,Brazil:Modern Precambrian relics

Sedimentary Geology,2006185(3-4):175-183.

[本文引用: 1]

Henrichs S M.

Early diagenesis of organic matter:The dynamics (rates) of cycling of organic compounds

∥Engel M H,Macko S A. Organic geochemistry. Springer Boston MA,1993101-117.

[本文引用: 1]

Hunter K SWang Y FVan Cappellen P.

Kinetic modeling of microbially⁃driven redox chemistry of subsurface environments:coupling transport,microbial metabolism and geochemistry

Journal of Hydrology,1998209(1-4):53-80.

[本文引用: 1]

Lovley D R.

Dissimilatory Fe(III) and Mn(IV) reduction

Microbiological Reviews,199155(2):259-287.

[本文引用: 1]

Monien PSchnetger BBrumsack H Jet al.

A geochemical record of late Holocene palaeoenvironmental changes at King George Island (maritime Antarctica)

Antarctic Science,201123(3):255-267.

[本文引用: 1]

Gerringa L J A.

Aerobic degradation of organic matter and the mobility of Cu,Cd,Ni,Pb,Zn,Fe and Mn in marine sediment slurries

Marine Chemistry,199029355-374.

[本文引用: 1]

Banner J L.

Application of the trace element and isotope geochemistry of strontium to studies of carbonate diagenesis

Sedimentology,199542(5):805-824.

[本文引用: 1]

李双应金福全王道轩.

碳酸盐岩成岩作用的微量元素地球化学特征

石油实验地质,199517(1):55-62.

[本文引用: 1]

Li S YJin F QWang D X.

Geochemical characteristics of carbonate rock diagenesis

Experimental Petroleum Geology199517(1):55-62.

[本文引用: 1]

邹建军石学法李双林.

北黄海浅表层沉积物微量元素的分布及其早期成岩作用探讨

海洋地质与第四纪地质,200727(3):43-50.

[本文引用: 2]

Zou J JShi X FLi S L.

Distributions of minor elements in near surface sediments in north Yellow Sea and the early diagenesis

Marine Geology & Quaternary Geology200727(3):43-50.

[本文引用: 2]

Shaw T JGieskes J MJahnke R A.

Early diagenesis in differing depositional environments:the response of transition metals in pore water

Geochimica et Cosmochimica Acta,199054(5):1233-1246.

[本文引用: 1]

Piper D Z.

Seawater as the source of minor elements in black shales,phosphorites and other sedimentary rocks

Chemical Geology,1994114(1-2):95-114.

[本文引用: 4]

Zheng YAnderson R Fvan Geen Aet al.

Authigenic molybdenum formation in marine sediments:a link to pore water sulfide in the Santa Barbara Basin

Geochimica et Cosmochimica Acta,200064(24):4165-4178.

[本文引用: 1]

Algeo T JMaynard J B.

Trace⁃element behavior and redox facies in core shales of Upper Pennsylvanian Kansas⁃type cyclothems

Chemical Geology,2004206(3-4):289-318.

[本文引用: 1]

Takahashi SYamasaki S IOgawa Yet al.

Bioessential element⁃depleted ocean following the euxinic maximum of the end⁃Permian mass extinction

Earth & Planetary Science Letters,201439394-104.

[本文引用: 2]

Tostevin RShields G ATarbuck G Met al.

Effective use of cerium anomalies as a redox proxy in carbonate⁃dominated marine settings

Chemical Geology,2016438146-162.

[本文引用: 3]

Lovley D RPhillips E J PGorby Y Aet al.

Microbial reduction of uranium

Nature,1991350(6317):413-416.

[本文引用: 1]

Canfield D EThamdrup BHansen J W.

The anaerobic degradation of organic matter in Danish coastal sediments:iron reduction,manganese reduction,and sulfate reduction

Geochimica et Cosmochimica Acta,199357(16):3867-3883.

[本文引用: 1]

Canfield D EThamdrup B.

Towards a consistent classification scheme for geochemical environments,or,why we wish the term ‘suboxic’ would go away

Geobiology,20097(4):385-392.

[本文引用: 1]

Schunck HLavik GDesai D Ket al.

Giant hydrogen sulfide plume in the oxygen minimum zone off Peru supports chemolithoautotrophy

PLoS One,20138(8):e68661.

[本文引用: 1]

McManus JBerelson W MSevermann Set al.

Molybdenum and uranium geochemistry in continental margin sediments:paleoproxy potential

Geochimica et Cosmochimica Acta,200670(18):4643-4662.

[本文引用: 1]

Zeng ZTice M M.

Promotion and nucleation of carbonate precipitation during microbial iron reduction

Geobiology,201412(4):362-371.

[本文引用: 1]

/