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1.
Jens Wendler Jens Köster Jens Götze Norbert Kasch Norbert Zisser Jonas Kley Dieter Pudlo Georg Nover Reinhard Gaupp 《International Journal of Earth Sciences》2012,101(1):159-176
Fracture-related bleaching of Lower Triassic Buntsandstein red beds of central Germany was related to significant carbonate
diagenesis and feldspar alteration caused by CO2-rich fluids. Using cathodoluminescence microscopy and spectroscopy combined with electron microprobe analysis and stable
carbon isotope study, two major fluid–mineral interactions were detected: (1) zoned, joint-filling calcites and zoned pore-filling
calcite cements, the latter replacing an earlier dolomite, were formed during bleaching. During the calcite formation and
dolomite–calcite transformation, iron was incorporated into the calcite cement crystal cores due to Fe availability from the
coeval bleaching. The dedolomitisation was ultimately associated with a volume increase. The related permeability decrease
implies a certain degree of sealing and increasing retention of CO2, and the volume increase offers a minor CO2 sink. Carbonate-rich sandstone, therefore, can provide advantages for underground CO2 storage especially when situated in the fringes of the reservoir. (2) Alkali-feldspar alteration due to the bleaching fluids
is reflected in cathodoluminescence spectra predominantly by the modulation of a brown luminescence emission peak (~620 nm).
This peak represents a newly discovered effect related to alkali-feldspar alteration not solely associated with bleaching.
Its modulation by the bleaching is interpreted to be due to Na depletion or a lattice defect in the Si–O bonds of the SiO4-tetrahedron. Alteration reflected by this luminescence feature has a destructive effect on the feldspars implying the possibility
of diminished rock integrity due to bleaching and, hence, CO2-rich fluids. Two further CL spectral changes related to bleaching occur, (a) decreased intensity between around 570 nm assigned
to Mn-depletion, and (b) increased amplitude and wavelength shift of the red (~680 nm) band. Converging evidence from carbonate
and feldspar diagenesis, stable carbon isotope data and analysis of fracture directions suggests that CO2 fluids contributed to a significant extent to the bleaching phenomena and alteration in the studied Buntsandstein strata. 相似文献
2.
We compare the diagenetic evolution of deeply buried Rotliegend (Permian) red bed sandstones at the southern and northern
margin of the Central European Basin (CEB) in Germany. Main target is to evaluate the influence of maturation products from
hydrocarbon (HC) source rocks during red bed diagenesis. At the southern margin of the CEB, thick coal-bearing Carboniferous
source rocks are omnipresent beneath the Rotliegend. They contain dominantly gas-prone terrigenous organic material and some
oil source rocks. Hydrocarbons were generated from Late Carboniferous onwards throughout most of basin subsidence. At the
northern margin of the CEB, source rocks are almost absent due to deep erosion of Carboniferous rocks and a low TOC of local
Lower Carboniferous relics. Early diagenetic processes are comparable at both basin margins. Significant differences in burial
diagenetic evolution are spatially correlated to the occurrence of hydrocarbon source rocks. Burial diagenesis at the southern
margin of the CEB is characterized especially by bleaching of red beds, major dissolution events, pervasive illite formation,
impregnation of pore surfaces with bitumen, and formation of late Fe-rich cements. Almost none of these features were detected
at the northern basin margin. Instead, relatively early cements are preserved down to maximum burial depths. This suggests
that major diagenetic mineral reactions in deeply buried red bed sandstones are controlled by the presence or absence of maturing
hydrocarbon source rocks. 相似文献
3.
Seepage from hydrocarbon reservoirs can cause a number of chemical and/or mineralogical changes in overlying rocks and soils. These surface changes can be detected by remote sensing imaging systems. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is an advanced multispectral imaging system in the visible and near infrared (VNIR) to shortwave infrared (SWIR) region. Band ratios of ASTER VNIR and SWIR data to detect red bed bleaching and secondary carbonate formation induced by hydrocarbon seepage are proposed through analysis of the spectral properties of rock samples. Results show that ASTER band ratios of 2/1 and 4/8 can discriminate bleached red beds and secondary carbonate minerals due to hydrocarbon seepage in the northern Tian Shan. They are in good agreement with mineral identification using X‐ray diffraction. The ratio technique derived from ASTER data may provide a potential approach for hydrocarbon exploration in areas with sparse vegetation cover. 相似文献
4.
Peter Turner 《Sedimentary Geology》1974,12(3):215-235
The Ringerike Group is a meandering fluviatile succession which is about 60% red. Most of the red zones are formed of mudrocks and siltstones and correspond to the fine members of fining-upwards cyclothems. The majority of coarse members are drab coloured.Textural studies of thin and polished sections show that the red colour is caused by finely crystalline hematite as matrix and grain-coatings. This hematite apparently crystallized post-depositionally. Hematite also occurs in other textural sites: within altered phyllosilicates, as detrital grains and as totally pseudomorphed phyllosilicates. This, and the lack of consistency between colour and clay mineralogy, suggests that the red beds have had a long and complex diagenetic history.Iron analyses indicate that the red beds are enriched in Fe3+ and total iron (FeO) by about 1%. This is thought to have been derived from the pre-depositional weathering of iron minerals and introduced into the sediments as amorphous iron hydroxide or iron-bearing clays. Crystallization of iron hydroxide under oxidizing conditions and the post-depositional alteration of iron-silicates and oxides is thought to be responsible for the formation of the red beds. 相似文献
5.
Jarmila Slánská 《Sedimentary Geology》1976,15(2):135-164
Tectonic activity, climatic changes and associated weathering cooperated during the formation of Upper Cretaceous red beds of the South Bohemian Basins known as the Klikov Formation.The sediments are clastic and comprise: (1) light-grey or yellow conglomeratic, course-to-medium sandstone beds; (2) generally finer red beds; and (3) grey beds. They alternate in asymmetrical cycles, in succession fining upwards. Small- and large-scale cyclothems were recognized. The large-scale cyclothems are closely connected with paleogeographical changes and tectonic evolution of the South Bohemian Basins in Early Senonian time. In regard to rapid vertical and lateral lithological variations, the common presence of graded bedding, poor sorting and lack of fossils, the sediments are comparable to the fluviatile facies of molasse, known as “flysch in molasse”. They were deposited from highly fluctuating currents and periodically overloaded streams in an alluvial and/or lacustrine environment, suffering continuously from tectonic unrest emanating from the Alpine—Carpathian geosyncline.Differences between red and grey sediments are related mostly to the primary distribution and preservation of organic matter and to some extent to the redistribution of iron during early diagenetic changes (e.g. red stains).Ancient weathered gneiss and granite profiles preserved beneath the sediments show development of either two (on granite) or three (on gneiss) horizons differing in degree of weathering and distribution of red colour within the profiles. The trend of weathering documented by chemical analyses and presence of kaolinite as the end-product points to the red podzolic soil formation process. 相似文献
6.
Klaus Germann Torsten Schwarz Mario Wipki 《International Journal of Earth Sciences》1994,83(4):787-798
The intra- and epicontinental basins in north-east Africa (Egypt, Sudan) bear ample evidence of weathering processes repeatedly having contributed to the formation of mineral deposits throughout the Phanerozoic.The relict primary weathering mantle of Pan-African basement rocks consists of kaolinitic saprolite, laterite (in places bauxitic) and iron oxide crust. On the continent, the reaccumulation of eroded weathering-derived clay minerals (mainly kaolinite) occurred predominantly in fluvio-lacustrine environments, and floodplain and coastal plain deposits. Iron oxides, delivered from ferricretes, accumulated as oolitic ironstones in continental and marine sediments. Elements leached from weathering profiles accumulated in continental basins forming silcrete and alunite or in the marine environment contributing to the formation of attapulgite/saprolite and phosphorites.The Early Paleozoic Tawiga bauxitic laterite of northern Sudan gives a unique testimony of high latitude lateritic weathering under global greenhouse conditions. It formed in close spatial and temporal vicinity to the Late Ordovician glaciation in north Africa. The record of weathering products is essentially complete for the Late Cretaceous/Early Tertiary. From the continental sources in the south to the marine sinks in the north, an almost complete line of lateritic and laterite-derived deposits of bauxitic kaolin, kaolin, iron oxides and phosphates is well documented. 相似文献
7.
我国红层分布特征及主要工程地质问题 总被引：24，自引：0，他引：24
我国中新生代红层分布总面积约826 389km2,是工程建设中不可避免的岩土体。南方地区红层约占红层总面积的60%,以西南、中南地区红层分布较广,多为裸露型红层,受降雨等因素影响滑坡、风化等问题突出;北方地区红层约占40%,以甘肃以及蒙宁晋陕交界红层分布相对较多,多为埋藏型红层,工程地质问题具有隐蔽性。红层分布受控于分布区的区域断裂带,岩体结构破碎,水文网络发育,渗流、软化等问题突出。由于砂岩、泥岩、页岩、蒸发岩、杂色岩等多种软硬岩层互层结构和工程活动等因素的影响,沿着软弱结构面易发生滑坡、差异风化等工程地质问题。由于时代较新,岩土体的胶结性差,物理力学性能相对较差,岩石多属于软岩类别。稳定性差,易崩解软化。蒸发岩和红层岩土体中可溶成份在水作用下,容易发生岩溶、腐蚀、渗流等物理化学问题。建议在工程建设中将红层作为特殊岩体对待。 相似文献
8.
Volkmar Stingl 《International Journal of Earth Sciences》1987,76(2):647-664
For the first time the origin of the Alpine Buntsandstein (Scythian) in the western part of the Northern Calcarous Alps is outlined by lithofacies types and their relations. The eastern realm of Tyrol seemed to be interesting because of the transition from the terrestric-fluviatile facies of the Alpine Buntsandstein to the marine Werfen beds and the marine influence on the Alpine Buntsandstein. Lithology and sedimentary petrology enable a classification as redcoloured Lower Buntsandstein and white and grey Upper Buntsandstein. Analyses of sedimentary structures, lithofacies types and paleocurrent directions show, that most of the Lower Buntsandstein is composed of sandstones of a braided fluvial system, whose uppermost part ist replaced by sediments of a coastal plain only in the eastern part of Tyrol. Marginal marine influence is testified by sporadic occurrence of gypsum, increased carbonate content, bimodal current directions and trace fossils (Diplocraterion). Fluviatile sedimentation of the Upper Buntsandstein, starting above, is rapidly suppressed by transgression of the »Werfen Sea« from E to W, resulting in the development of estuaries, lastly being replaced by the marine Werfen beds. 相似文献
9.
Yehya Al-Rawi 《Sedimentary Geology》1983,35(3):177-192
The Gercus Formation (Eocene) in northeastern Iraq consists of a fluvial sequence of associated red and drab beds deposited under an arid to semi-arid climate. Occurrence of pigment on grain contacts in the sandstones and the uniform distribution of pigment in the marls and siltstones indicate that part of the pigment is of predepositional or syndepositional origin, most probably detrital ferric hydroxides that coated the grains. Alteration and corrosion of iron oxides and ferromagnesian minerals, intensified pigment around some opaque grains, and decreased heavy-mineral content (compared to the recent river sediments in the area) point to intrastratal alteration and the diagenetic origin of part of the pigment. Iron contents indicate that leaching of ferric iron with an average of 1.41% Fe from the drab marl and siltstone beds and 0.74% Fe from the drab sandstone beds washed out the pigment (or its precursor) from these beds. 相似文献
10.
11.
黄土高原红粘土与黄土古土壤粒度特征对比--红粘土风成成因的新证据 总被引：39，自引：9，他引：30
对黄土高原具有代表意义四个剖面的晚第三纪红粘土样品进行了粒度分析,并将结果与典型风成黄土古土壤样品的粒度特征进行详细对比,得到红粘土是风成成因的沉积学证据。结果表明,黄土高原红粘土与其上覆第四纪古土壤形成环境相似,红粘土是在相对于黄土堆积搬运风动力变幅小的条件下沉积的,在沉积之后受到较强的风化成壤改造作用。 相似文献
12.
甘肃省平凉市灵台县邵寨镇剖面风尘堆积底界年龄大约为5.23 Ma B.P.,通过对该剖面新近纪红粘土与第四纪黄土-古土壤序列的常量元素、微量元素、Nd同位素的测试,分析其在物源和风化方面的指示意义,发现新近纪红粘土与第四纪黄土具有相似的常量、微量元素UCC标准化曲线和稀土元素球粒陨石标准化曲线,指示二者皆来自广阔的物源区,经过了相似的搬运过程,并在搬运中得到充分混合。新近纪红粘土的MgO、Li、Cs、Bi含量较高,Na2O、稀土元素La-Lu、Y含量较低。风化参数Na2O/Al2O3、化学风化参数CIA以及Al2O3-CaO+Na2O-K2O (A-CN-K)图,均显示新近纪红粘土比第四纪黄土经历了更为强烈的风化过程。新近纪红粘土的稳定元素比值(TiO2/Al2O3,SiO2/Al2O3,SiO2/TiO2,Zr/Hf,Nb/Ta,Lu/Hf,Y/Ho,Th/Nb和Hf/Nb)、稀土元素总量、轻稀土与重稀土的分异程度、轻稀土内部分异程度、重稀土内部分异程度、Ce和Eu的异常程度、同位素εNd(0) 值等,皆与第四纪黄土无太大差异,指示二者物质来源一致。粒度以及风化强度的差异,可能是导致新近纪红粘土与第四纪黄土常量和微量元素含量差异的主要原因。 相似文献
13.
K. N. Murali Krishna K. S. N. Reddy Ch. Ravi Sekhar P. Ganapathi Rao K. Bangaku Naidu 《Journal of the Geological Society of India》2017,89(1):111-111
The study presents the textural characteristics of late Quaternary red sediments of Bhimunipatnam to understand the process of formation of these sediments. The red sediments are classified into (a) yellow sediments (b) reddish brown sediments (c) brick red sediments and (d) light yellow sediments sequence in the vertical litho section. The yellow sediments, rests on the khondalite basement, comprises of medium grained, moderate to poorly sorted and positively skewed. The rounded pebble beds with trough cross bedding indicate high energy turbulent conditions of deposition. The fining upward sequences indicate sediments were deposited under decreasing energy conditions under fluvial regime.The iron bearing minerals like garnets and pyriboles have undergone chemical weathering under high oxidizing environment resulting in addition of silt and clay to the reddish brown and brick red sediments and concretions were formed by carbonate precipitation. These processes caused changes in the mean grain size and sorting nature of these sediments which are originally aeolian in origin. The light yellow sediments were medium to fine grained, well sorted and similar to modern dune sands in terms of textural parameters. These sediments were deposited under low oxidation environmental conditions and acquired yellow colour due to Fe hydroxides. 相似文献
14.
通过对红层残积红土的粒度成分、矿物成分、化学成分、物理化学特性、宏观结构、微观结构特征的全面系统分析，揭示红层残积红土不仅经历了物理风化作用，而且经受过红土化作用，具有红土的一般特点，是一种强度稍高，压缩性中等，含较多游离氧化物的超固结土。最后对红层残积红土的工程地质评价提出建议，认为其特性与母岩有关，砂砾岩、砂岩残积红土接近花岗岩残积红土；粉砂岩、泥岩残积红土接近红粘土，并对地基承载力和变形等问题提出具体的评价意见。 相似文献
15.
塔里木盆地塔河地区海西晚期火山岩构造特征与油气成藏 总被引：1，自引：0，他引：1
通过地震剖面解释,根据断裂的切割层位将研究区火山岩断裂分为3类,即深层断裂、浅层断裂、火山岩内部微断裂。通过编制这3类断裂的平面展布图,对塔河地区火山岩断裂的性质、形成期次、分布特征及形成机理进行了分析。认为深层断裂形成于加里东期-海西期,以逆冲断层为主,走向呈NNE、NE、NNW3组,断裂主要分布于塔河火山岩发育区北部、西北部。浅层断裂形成于燕山期-喜马拉雅期,以正断层为主,断裂走向呈NE、NNE向,主要分布于盐边地带和东南部盐上火山岩分布区。火山岩内部的微断裂在顶部较底部发育,主要分布于塔河地区西部的火山岩中。根据火山岩储层和构造成因类型,将塔河地区火山岩划分为3种圈闭类型,即:构造裂缝和淋滤风化共同控制的圈闭、古凸起不整合遮挡和抬升淋滤风化共同控制的圈闭、埋藏溶蚀和构造裂缝共同控制的圈闭。分析了火山岩圈闭顶部的盖层条件和火山岩的油气成藏条件,认为三叠系底部柯吐尔组泥岩可形成有效的区域性封盖,塔河地区火山岩具有良好的油气成藏条件。 相似文献
16.
基于遥感技术的龙门山前山带烃类微渗漏信息提取 总被引：1，自引：0，他引：1
通过对龙门山前山带含油区与非含油区的岩石、土壤、植被等进行测试,认为烃类微渗漏会造成地表热异常、红层褪色、低价铁富集以及粘土矿化等现象,并对研究区的粘土矿物、Fe3+、Fe2+与烃类的波普曲线特征进行了分析对比。以ETM卫星图像为主要信息源,选择了TM2/TM3、TM3/TM4和TM5/TM7进行比值处理,从光谱数据中直接提取出碳酸盐化、粘土矿化、红层褪色等油气蚀变信息,并在对研究区遥感地质解译的基础上,指出烃渗漏信息异常晕主要沿断裂带分布,特别在不同走向断裂的交汇区域分布面积和强度较大,而在已知油气圈闭区域,信息晕主要呈碎片状或斑点状零散分布,且以低值异常为主。根据烃渗漏异常的分布特征,提取出石板滩、中坝、孝泉、聚源、鸭子河以及邛崃等遥感信息异常区块。 相似文献
17.
鄂尔多斯盆地东胜砂岩型高岭土矿特征及成因机制 总被引：1，自引：0，他引：1
东胜砂岩型高岭土矿床位于鄂尔多斯盆地东北部,含矿层为延安组。经薄片鉴定、扫描电镜、X-衍射、全岩主要元素分析（XRF）以及稀土元素地球化学分析,对矿层白色砂岩与红色原岩的岩石地球化学特征进行了对比。结果表明,原岩为基质被铁质浸染的以碎屑片状高岭石和伊利石为主的红色砂岩,而矿层则为褪色的以粒度粗细不一的高岭石胶结为主的白色砂岩。矿层砂岩的分布与盆地北部油苗位置具有很好的对应关系。综合区域地质特征、岩石学、岩石化学以及天然气运散的信息,认为砂岩型高岭土矿层的形成是由于研究区以南气田中的上古生界天然气向北运移散失过程中,将红色原岩中的氧化铁胶结物还原成易于运移的Fe2+,从而使其褪色变白;同时酸性流体使长石溶蚀形成高岭石,后期的风化淋滤作用使砂岩中的高岭石含量进一步提高,进而形成目前较大规模的高岭土矿床。 相似文献
18.
Yu Zou Dongna Liu Hongwei Kuang Changgui Song Yuxiang Sun 《International Geology Review》2020,62(11):1433-1449
ABSTRACT Mesoproterozoic red beds near ancient coasts have not aroused extensive interest. A new geochemical study of the alternating red and grey dolostones from the Yangzhuang Formation provides a better understanding of the redox conditions of nearshore sedimentary environments. In this contribution, whole-rock samples are characterized by positive correlations of rare earth elements (REE) vs. Th and FeT vs. Th and flat-type REE distribution patterns, indicating massive terrigenous input, which is considered to be inherited from felsic rocks. Relatively high (Femag+Feox)/FeT and Fe3+/Fe2+ ratios in red beds indicate more oxidized conditions in supratidal environments compared with the lower oxygen contents in intertidal environments. Under these two distinct chemical sedimentary conditions, acetic acid-leached red and grey samples both have HREE-depleted distributions, suggesting significant freshwater invasion. Moreover, limited terrigenous redox-sensitive elements (RSEs) can reach the coast where the red beds are deposited, whereas relatively high RSE enrichment factors originating from shallow oceans are recorded in grey beds. In the Mesoproterozoic, limited oxidative weathering, shallow seawater desalination, and low organic production occurred near the coast. Meanwhile, a prolonged period of low Mo and U availability preserved in carbonate minerals confirmed that marine oxygen levels failed to satisfy the deposition of offshore red beds. During the regression, potentially exposed sediments connected to atmospheric oxygen guaranteed the oxidation of iron and the formation of red beds, and these events were coupled with negative δ13Ccarb shifts in the Yanliao rift zone. 相似文献
19.
月表矿物含量反演是研究月球地质起源和演化的关键.太空风化作用普遍发生在月球表面,对矿物纯净光谱造成了不可忽视的影响,它弱化光谱吸收特征, 降低反射率,影响矿物含量遥感反演精度.基于Relab光谱库和Hapke辐射传输模型,将月表 4种矿物(单斜辉石、斜方辉石、斜长石、橄榄石)的二向性反射率转换成同向性的单次散射反照率,然后计算矿物的光学常数;再根据亚微观金属铁SMFe(submicroscopic metallic iron)的质量分数模拟6种不同程度太空风化效应,得到端元矿物的反射率光谱;最后基于上述方法,利用多端元线性分解方法和M3(moon mineralogy mapper,月球矿物绘图仪)高光谱数据反演不同风化程度下的矿物含量,得到月表虹湾地区辉石、斜长石、橄榄石3种矿物的含量分布.实验表明,利用多端元线性分解可以有效模拟太空风化效应对矿物光谱的影响,是研究太空风化效应影响下矿物识别及含量反演的一种行之有效的方法. 相似文献