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1.
千佛岩组发育冲积扇、曲流河、三角洲和湖泊沉积。曲流河发育洪泛平原和河道两个亚相;三角洲发育三角洲前缘、三角洲平原及前三角洲三个亚相;湖泊相则发育浅湖和滨湖亚相;冲积扇分出扇中和扇端两个亚相。龙门山系周期性推覆构造活动是川西前陆盆地沉积作用及层序发育的主控因素。 相似文献
2.
川西前陆盆地上侏罗统蓬莱镇组沉积特征 总被引：1，自引：0，他引：1
经岩性、岩石组合、沉积韵律等综合分析认为川西前陆盆地上侏罗统蓬莱镇组主要为冲积扇、曲流河、三角洲和湖泊沉积.其中冲积扇发育扇中和扇端两个亚相,扇根不发育;曲流河发育河道和洪泛平原两个亚相;三角洲发育三角洲平原、三角洲前缘以及前三角洲三个亚相;而湖泊相主要发育滨浅湖和半深湖沉积,深湖在研究区内不发育.在龙门山前缘的盆地边缘发育冲积扇相带.大小不同的冲积扇体连接或叠覆构成冲积扇群.并依次出现扇中、扇端的微相分带.同时砾石由粗变细,逐渐过渡到河流的砂岩相;由河流往东则进入湖泊沉积区,并在河流入湖处形成三角洲相沉积.根据冲积扇-曲流河-三角洲一湖泊的时空展布规律,建立了本区蓬莱镇组的沉积模式. 相似文献
3.
依据钻井、露头及岩心资料,结合区域地质特征,详细研究了川西前陆盆地下侏罗统白田坝组沉积相和岩相古地理特征。结果表明,川西前陆盆地下侏罗统白田坝组主要发育冲积扇相、曲流河相、湖泊三角洲相和湖泊相4种沉积相类型。冲积扇相主要发育扇中和扇端两个亚相,扇根不发育;曲流河相发育河道和洪泛平原两个亚相;湖泊三角洲相发育三角洲平原、三角洲前缘两个亚相,前三角洲亚相不发育;湖泊相主要发育滨浅湖亚相和半深湖亚相,深湖亚相不发育。龙门山前缘的邛崃、安县、江油、旺苍、南江等地冲积扇广泛发育,大小、形状不同的冲积扇连接叠覆构成冲积扇群。在安县地区发育的冲积扇往东砾石由粗变细,逐渐过渡到河流的砂岩相。在金堂、三台等地河流入湖形成三角洲相沉积,并由三角洲进入湖泊沉积区,构成冲积扇—河流—三角洲—湖泊的沉积模式。 相似文献
4.
准噶尔盆地南缘上三叠统黄山街组主要为砾岩、含砾砂岩、砂岩、粉砂岩和泥岩构成的一套碎屑岩组合,野外沉积特征研究确定为典型的辫状河三角洲沉积。通过对沉积相、亚相、微相的详细研究,认为辫状河三角洲具有类似曲流河三角洲的层序结构和微相类型,但两者间也存在很大的差别。与曲流河三角洲相比,辫状河三角洲的三角洲平原亚相不仅沉积物的粒度较粗,而且辫状河道沉积较发育,河道间洪泛平原沉积不发育。辫状河三角洲前缘亚相也可以识别出水下分流河道、河口坝、席状砂和水下分流河道间等微相,水下分流河道沉积为主体。根据野外露头的追索研究,建立了准噶尔盆地南缘上三叠统黄山街组辫状河三角洲的沉积模式。从沉积物的岩性特征看,辫状河三角洲砾岩和含砾粗砂岩体具有分布较稳定、展布较广、储集物性较好的特点。 相似文献
5.
利用研究区内精细岩芯观察,录井及测井等资料,从岩石特征、沉积构造、岩相组合和古生物等相标志入手,系统分析了松辽盆地临江南地区扶余油层沉积微相展布特征及沉积模式。研究揭示临江南地区扶余油层为曲流河-浅水三角洲沉积体系,主要发育的沉积微相类型有分流河道、决口扇、洪泛沉积、水下分流河道、水下决口扇、支流间湾、曲流河道、天然堤和河漫滩等。通过地震属性优选,结合单井和连井资料表明:纵向上,从FⅢ2到FⅡ1为一套三角洲平原亚相向曲流河相演化的进积沉积序列,在FⅡ1沉积后期,发生了全盆地范围的湖侵事件,导致从FⅠ3到FⅠ1为一套曲流河相向三角洲前缘亚相演化的退积沉积序列,并建立了临江南地区扶余油层的沉积模式。 相似文献
6.
通过对准噶尔盆地西北缘野外露头剖面和检188井区160多口井的岩石学特征、颜色、结构、沉积构造和古生物沉积相标志的研究,结合测井曲线响应特征,认为该区下侏罗统八道湾组属于湿润型辫状河沉积,发育河道和洪泛平原两个亚相。河道亚相又分为主水道、支水道和心滩3个微相,洪泛平原分为河漫滩、河漫沼泽和溢岸3个微相。测井曲线主要有箱形、钟形、漏斗形、指形和微齿形5种类型。在微相分析基础上编制了八道湾组12个小层的沉积微相平面图,建立了沉积相模式,指出河道呈东南向展布,认为由前陆湖盆边界区的造山运动导致的沉积区基准面变化和潮湿温暖的气候是影响研究区湿润型辫状河形成的主要控制因素。 相似文献
7.
主要通过岩心观察、粒度分析、参数计算、录井及测井分析等手段,充分吸收国内外河流研究成果,结合研究区区域地质背景,总结出渤海湾盆地垦东凸起北坡新近系馆陶组上段沉积相模式。研究认为：馆上段为河流相沉积,从沉积物特征和平面形态角度可以将研究区馆上段河流理解为介于辫状河与曲流河之间的过渡河型。其平均河道弯曲度大于1.7,垂向层序表现为泥多砂少,具有曲流河的特征;但沉积层序顶部常直接覆盖河漫/洪泛平原沉积,特别是河道内砂坝发育造成河道分汊河,砂坝沉积物粒度特征反映的受洪水控制的震荡性特点而与曲流河有重要差别。作者借用在水利学界和地貌学界广为使用的分汊河概念,建立了馆上段沉积相模式,包括河床、堤岸、河漫/洪泛平原和废弃河道等4个亚相,其沉积物组成下粗上细的正韵律。其中,河道砂坝是其主要砂体,顶部常被洪泛平原直接覆盖;决口扇是仅次于河道砂坝的次要砂体。 相似文献
8.
本文通过岩心观察、录测井及岩心粒度资料,埘鄂尔多斯盆地麻黄山西区块北部中侏罗统延安组延一段的岩石组分、结构构造、粒度分布等特征进行分析,确定其沉积相类型。结果表明：延安组延一段属河流沉积体系,发育辫状河和曲流河两种沉积类型,主要包括河床和河漫两个亚相,可进一步识别出河床滞留、心滩、边滩、河漫滩、河漫沼泽、决口扇等微相。延一段延10油层组沉积时期,研究区以辫状河沉积为主,心滩发育,河道较宽,平面上摆动宽度为2～8km,主水流方向由西北至东南;延一段延9油层组沉积时期,受鄂尔多斯盆地湖水面整体抬升的影响,河道分布范围逐渐缩小,研究区以曲流河沉积为主,发育两条曲流河,平面上摆动宽度约2～4km,河道凸岸发育边滩沉积。 相似文献
9.
《现代地质》2015,(6)
以松辽盆地东南缘籍家岭泉头组露头为研究对象。通过对露头的野外实测及粒度分析,揭示了籍家岭泉头组露头是由冲积扇演化为曲流河相的典型露头剖面。垂向上,露头从0~28 m发育冲积扇相,28~70 m发育辫状河相,70~510 m发育曲流河相。其中冲积扇相发育扇中、扇端2种亚相,区分出泥石流沉积、泥流沉积、扇面河道沉积、漫流沉积、淤积物5种微相。辫状河相发育河道、河漫2种亚相,区分出滞留沉积、心滩、河漫滩3种微相。曲流河相发育河道、堤岸及河漫3种亚相,区分出滞留沉积、边滩、天然堤、决口扇、河漫滩5种微相。粒度概率曲线分析结果显示:冲积扇为悬浮一段式及滚动—跳跃—悬浮三段式、辫状河为滚动—跳跃—悬浮三段式、曲流河为跳跃—悬浮二段式的组合特征。冲积扇—辫状河—曲流河这一演化过程反映了松辽盆地东南缘泉头组沉积时期较大的地势高差—陡坡—准平原化的古地理背景。 相似文献
10.
主要通过岩心观察、粒度分析、参数计算、录测井分析等手段,充分吸收国内外河流研究成果,结合研究区区域地质背景,揭示垦东凸起北坡馆上段沉积相模式。得到以下认识：研究区馆上段地层为河流相沉积,从沉积物特征和平面形态角度可以将研究区馆上段河流沉积理解为介于辫状河及曲流河之间的过渡河型。其平均河道弯曲度大于1.7,垂向层序表现为泥多砂少,具有曲流河的特征;但沉积层序顶部常直接覆盖河漫/洪泛平原沉积,特别是河道内砂坝发育造成河道分汊河,砂坝沉积物粒度特征反映受洪水控制的震荡性特点而与曲流河有重要差别。本文借用在水利学界和地貌学界广为使用的分汊河概念建立了研究区馆上段沉积相模式,包括河床、堤岸、河漫/洪泛平原、废弃河道等4个亚相,组成下粗上细的正旋回。其中,河道砂坝是其主要砂体,顶部常被洪泛平原直接覆盖;决口扇是仅次于河道砂坝的第二大砂体。 相似文献
11.
Moutaz A. Al-Dabbas Jassim A. Al-Jassim Amanj I. Qaradaghi 《Arabian Journal of Geosciences》2013,6(12):4771-4783
The depositional facies and environments were unraveling by studying 21 subsurface sections from ten oilfields in the central and southern Iraq and a large number of thin sections of the Nahr Umr (siliciclastic deposit) Formation (Albian). This formation is mainly composed of sandstone interlaminated with minor siltstone and shale, with occurrence of thin limestone beds. Nahr Umr Formation is subdivided into three lithostratigraphic units of variable thicknesses on the basis of lithological variations and log characters. Mineralogically and texturally, mature quartz arenite and sandstones are the common type of the Nahr Umr Formation. The sandstones are cemented by silica and calcite material and have had a complex digenetic history. Compaction, dissolution, and replacements are the main diagenetic processes. Prodelta, distal bar, distributary mouth bar, distributary channel, over bank, and tidal channel are the main depositional environments recognized for the Nahr Umr Formation, within the studied wells. This formation was deposited in shallow marine and fluvial–deltaic environments and exhibit progradational succession of facies. Eight sedimentary facies that have been identified in the Nahr Umr Formation include claystone lithofacies, claystone siltstone lithofacies, lenticular-bedded sandstone–mudstone lithofacies, wavy-bedded sandstone–mudstone lithofacies, flaser-bedded sandstone–mudstone lithofacies, parallel and cross lamination sandstone lithofacies, trough cross-bedded sandstone lithofacies, and planar cross-bedded sandstone lithofacies. The depositional model of the Nahr Umr Formation environment was built based on the lithofacies association concepts. 相似文献
12.
The 2.6 Ga Keskarrah Formation, located in the central Slave Province, Northwest Territories, Canada, is a late-orogenic, tectonically controlled sedimentary sequence that developed under unusual climatic and depositional conditions. The formation is adjacent to the crustal-scale, north-trending Beniah Lake Fault and overlies the 3.15 Ga Augustus Granite, the 2.69–2.7 Ga mafic volcanic Peltier Formation and the turbiditic Contwoyto Formation unconformably. Principal lithofacies in the Keskarrah Formation include conglomerate, sandstone and siltstone–sandstone. The conglomerate lithofacies represents coalescing gravelly streamflow-dominated fan deltas adjacent to topographic highs. Up-section quartz-rich arenites and quartz arenites of the sandstone lithofacies are interpreted to be shallow-water shoreface deposits influenced by wave action and tides. The overlying feldspathic litharenites of the siltstone–sandstone lithofacies are consistent with a lower shoreface to proximal offshore environment dominated by wave and tide interaction. Tidal influence in both sandstone-dominated lithofacies is inferred from the presence of mudstone laminae between bedforms and on foresets of cross-beds, as well as from abundant reactivation surfaces with local mudstone drapes. Intense chemical weathering during the Archaean, resulting from elevated atmospheric
levels, higher temperatures and moist climatic conditions, played an important role in the development of quartz-rich arenites that appear to be first-cycle deposits. Few lithic fragments and feldspar grains are preserved due to in-situ host rock weathering, chemical weathering during transport and wave and tide action. Hydraulic sorting and abrasion in the shoreface environment contributed to the continued breakdown and transport of labile minerals. Increased proportions of lithic fragments in sandstone beds of the conglomerate lithofacies are the result of shorter transport distances from source areas to the depositional environment. Abundant conglomerate with up to 4-m large granitic boulders derived from the adjacent Augustus Granite and mafic clasts from the Peltier Formation indicate high relief and fault-related uplift and subsidence. The intimate association of fan deltas and wave- and tide-influenced shallow-marine deposits in association with quartz-rich sandstones forming in a high-relief area make the Keskarrah Formation remarkable in the rock record. 相似文献
13.
14.
Farouk Mohammad El-Fawal Hesham Mostafa El-Asmar Mohammad Abd El-Fattah Sarhan 《Arabian Journal of Geosciences》2013,6(3):749-760
The Middle-Upper Eocene rocks of the Fayum District are represented by Gehannam, Birket Qarun and Qasr El-Sagha formations. Both field studies and laboratory analyses on the concerned rocks have enabled to distinguish six lithofacies: (1) sheet-like grey silt-shale, (2) large-scale trough cross-bedded sandstone, (3) successive varicolored mud-shale/siltstone intercalation, (4) dark grey to black mud-shale/sandstone intercalation, (5) thinly bedded sandstone-shale intercalation and (6) very large-scale cross-stratified sandstone. These lithofacies proved that the present rocks were deposited in transitional paralic environment of active northward-prograding deltaic subenvironments contemporaneous with rabid but gradual sea level drop. The depositional system started with the delta front silt-shale (Gehannam Formation) of 20 m thickness, followed by distributary mouth bars of cross-bedded sandstone (Birket Qarun Formation, 50 m thick). Both the lower and upper delta plains attain thicknesses of 99 and 38 m, respectively, and are represented by the lower part of Qasr El-Sagha Formation. The deltaic sequence is topped with 45-m-thick eolian sandstones representing the upper part of Qasr El-Sagha Formation. This unit represents an extensive desertification phase that closes the depositional history of the succession examined. 相似文献
15.
厄瓜多尔Oriente盆地南部区块Napo组层序地层模式与岩性地层圈闭预测 总被引：3，自引：1，他引：2
应用经典层序地层学方法,通过不整合面、钻测井等标志将厄瓜多尔Oriente盆地南部区块Napo组划分为5个三级层序;以地层叠置样式、岩性、岩相的变化细分出陆架边缘、海侵和高位体系域。陆架边缘体系域以潮汐水道沉积为特征;海侵体系域以广泛分布的陆棚相泥岩沉积为特征;高位体系域发育加积式陆棚相灰岩沉积。最后识别出潮汐水道砂体、水下浅滩和M1岩性尖灭带3种有利的岩性地层圈闭,综合预测Oriente盆地南部区块Napo组的潮汐水道砂体发育区是最有利的勘探方向。 相似文献
16.
Muhammad Zaheer Muhammad Sabir Khan Muhammad Saleem Mughal Noman Abbasi 《Arabian Journal of Geosciences》2017,10(23):514
The clastic sediments of the Murree Formation of Miocene age are exposed in Jhelum valley areas of Azad Jammu and Kashmir Pakistan. Field observations revealed the cyclic deposition in the Murree Formation. The sandstone, siltstone, and shale constitute a single cycle within the formation. This single unit is divided into five different lithofacies which constitute the Bouma sequence in the Murree Formation. The Murree Formation shows faulted contacts with Panjal Formation and Nagri Formation in the study area. The modal mineralogy data obtained from the petrography of sandstone indicates that sandstone is litharenite and lithic greywacke. The mineralogical and textural data suggests that sandstone is compositionally mature and poorly to moderately sorted. The dominantly angular to sub angular quartz grains show nearness of the source area. Fractured and sutured quartz grain reveals tectonodiagentic changes that occurred in Murree Formation. The sandstone experienced diagenetic changes. The pressure solution and cementation reduced the primary porosity of sandstone. However, alteration of feldspar and fractures in grains have produced secondary porosity. The X-ray diffraction (XRD) of the shale samples indicates that shale of the Murree Formation is argillaceous and dominated by illite clay mineral. The illite crystallinity values indicate very low grade metamorphism of Murree Formation in core of Hazara Kashmir Syntaxis. The petrographic data suggests that the provenance of sandstone is recycled orogen. Quartz is of igneous and metamorphic origin. Feldspar (albite and microcline) composition suggests its derivation from acidic igneous rocks. The rock fragments of volcanics, slate, phyllite, and schist suggest igneous and metamorphic provenance. The petrographic data suggests that at the time of deposition of Murree Formation, igneous and low grade metamorphic rocks were exposed. However, presence of some clasts of carbonates indicates that sedimentary rocks were also exposed in the source region. The quartz content and clay minerals in the shale revealed that source region was igneous and metamorphic rocks. Cyclic deposition, lithofacies, and various sedimentary structures like cross bedding, ripple marks, and calcite concretions suggest that deposition of Murree Formation occurred in fluviatile environment by meandering river system having decreasing turbidity current. 相似文献
17.
鄂尔多斯盆地延长组深水岩相发育特征及其石油地质意义 总被引：1，自引：0，他引：1
鄂尔多斯盆地湖盆中部地区三叠系延长组长7油层组广泛发育深水沉积。沉积物的粒度、沉积结构与构造、有机地球化学等特征研究表明,深水沉积岩可划分为四种岩相类型,分别为油页岩岩相、暗色泥岩岩相、砂质泥岩与泥质砂岩岩相和砂岩岩相。其中,油页岩岩相有机碳含量高,有机质类型好,测井曲线具有高阻、高伽马、低电位和时差跳跃频繁等特征;暗色泥岩岩相具有富含有机质、中低阻、中高伽马、高密度和高时差等特征;砂质泥岩与泥质砂岩岩相具有中电阻、低伽马、高密度、时差跳跃频繁等特征,泥质含量 20~70%;砂岩岩相表现出低的电阻、时差和伽马、泥质含量小于20%的特征,并刻画了各种深水岩相的剖面发育特征。深水斜坡带和湖底平原区的岩相组合存在较大的差异。深水岩相对非常规油气资源意义重大,其中油页岩岩相和暗色泥岩岩相为盆地中生界主力烃源岩,深水砂岩岩相是盆地大规模致密油的重要储集体,砂质泥岩与泥质砂岩岩相、暗色泥岩岩相富含丰富的页岩油资源,也具有潜在经济价值。 相似文献
18.
The Buller Coalfield on the West Coast of the South Island, New Zealand, contains the Eocene Brunner Coal Measures. The coal measures unconformably overlie Paleozoic-Cretaceous basement rocks and are conformably overlain by, and laterally interfinger with, the Eocene marine Kaiata Formation. This study examines the lithofacies frameworks of the coal measures in order to interpret their depositional environments. The lower part of the coal measures is dominated by conglomeratic lithofacies that rest on a basal erosional surface and thicken in paleovalleys incised into an undulating peneplain surface. These lithofacies are overlain by sandstone, mudstone and organic-rich lithofacies of the upper part of the coal measures. The main coal seam of the organic-rich lithofacies is thick (10–20 m), extensive, locally split, and locally absent. This seam and associated coal seams in the Buller Coalfield are of low- to high-volatile bituminous rank (vitrinite reflectance between 0.65% and 1.75%). The main seam contains a variable percentage of ash and sulphur. These values are related to the thickening and areal distribution of the seam, which in turn, were controlled by the nature of clastic deposition and peat-forming mire systems, marine transgression and local tidal incursion. The conglomeratic lithofacies represent deposits of trunk and tributary braided streams that rapidly aggraded incised paleovalleys during sea-level stillstands. The main seam represents a deposit of raised mires that initially developed as topogenous mires on abandoned margins of inactive braidbelts. Peat accumulated in mires as a response to a rise in the water table, probably initially due to gradual sea-level rise and climate, and the resulting raised topography served as protection from floods.The upper part of the coal measures consists of sandstone lithofacies of fluvial origin and bioturbated sandstone, mudstone and organic-rich lithofacies, which represent deposits of paralic (deltaic, barrier shoreface, tidal and mire) and marine environments. The fluvial sandstone lithofacies accumulated in channels during a sea-level stillstand. The channels were infilled by coeval braided and meandering streams prior to transgression. Continued transgression, ranging from tidal channel-estuarine incursions to widespread but uneven paleoshoreline encroachment, accompanied by moderate basin subsidence, is marked by a stacked, back-stepping geometry of bioturbated sandstone and marine mudstone lithofacies. Final retrogradation (sea-level highstand) is marked by backfilling of estuaries and by rapid landward deposition of the marine Kaiata Formation in the late Eocene. 相似文献
19.
珠江口盆地珠一坳陷珠海组三角洲沉积特征 总被引：3，自引：0，他引：3
利用珠江口盆地珠一坳陷珠海组取心井、测井及地震资料,探讨了珠海组三角洲沉积的岩石相、沉积微相、沉积亚相特征及发育分布规律,分析了其岩电响应特征,进而建立岩电响应模式,并通过研究区井-震对比,建立了珠海组三角洲沉积的地震响应模型. 相似文献
20.
西藏山南地区琼结南部上三叠统郎杰学群由轻微变质的泥质岩和碎屑岩组成,其中,砂岩主要为(岩屑)长石(杂)砂岩和(长石)岩屑(杂)砂岩,碎屑的分选和磨圆度较差,成分和结构成熟度较低,经历了压溶、交代及胶结等成岩作用;发育与浊积岩相关的层面、层理构造及沉积旋回发育。研究表明,按照宋热组、江雄组和姐德秀组地层层序,郎杰学群岩相总体呈现外—中扇砂板岩相向中—内扇砂板岩含砾岩相演化,向上变粗变浅,中源和近源/分支水道亚相增加;以姐德秀组下段中部为界可分为A和B两个层序,它们分属浊积扇演化的两个不同阶段;推测研究区及邻近地区可能存在一个较大规模向南迁移进积的舌状浊积扇。 相似文献