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31.
玉田啤酒厂饮用天然矿泉水井位于城关镇三里屯西200m,玉田酒厂院内,矿泉水赋存于第四系砂、砾卵石层中,属含锶、偏硅酸的重碳酸钙·镁型矿泉水,现已开发利用。  相似文献   
32.
丹霞地貌概念讨论   总被引:8,自引:0,他引:8  
刘尚仁  刘瑞华 《山地学报》2003,21(6):669-674
关于丹霞地貌概念上的不同意见,主要是:①岩性岩相上是较单一的“陆相碎屑岩”还是涵盖多种岩性岩相的“沉积岩”;②地貌上是“丹崖”,还是“赤壁丹崖”,或是“赤壁丹崖群”。根据目前已知的中外丹霞地貌的基本特征,初步认为,丹霞地貌是由砂岩砾岩为主的沉积岩经侵蚀作用所形成的赤壁丹崖群地貌。近10a来,一些丹霞地貌概念,基本上属于“中国丹霞地貌”的概念,不完全符合世界丹霞地貌的实际情况。  相似文献   
33.
ABSTRACT

The Early Cretaceous was an important epoch in the evolution of the Earth system in which major tectonic episodes occurred, especially along the Alpine–Himalayan belt. The paucity of reliable palaeogeographic data from the central segment of this geological puzzle, however, hampers the reconstruction of a panoramic view of its Early Cretaceous palaeogeography and geodynamic setting. Here we present multidisciplinary provenance data from Lower Cretaceous strata of the overriding plate of the Neo-Tethyan subduction zone (the Sanandaj–Sirjan Zone; SSZ, of central Iran), including structural, basin-fill evolution, petrographic and geochemical analyses. Sandstone provenance analysis of Lower Cretaceous red beds suggests the occurrence of sub-mature litho-quartzose sandstones attributed to an active continental arc margin in convergent setting predominantly derived from plutonic, quartzose sedimentary and metamorphic rocks exposed in the central SSZ. Weathering indices indicate moderate chemical weathering in the source area which may be related to close source-to-sink relationships or arid climate. Our palaeogeographic reconstructions and original geological mapping indicate that the erosion of uplifted basement rocks exposed in horst blocks provided the sediment sources for the syn-extensional deposition of uppermost Jurassic–lowermost Cretaceous conglomerates and Lower Cretaceous siliciclastic red beds within a continental retro-arc basin during initiation of the ‘Neo-Tethys 2?. The polyphase tectonic reactivation along the principal fault of the study area controlled the syn- and post-extensional tectonostratigraphic evolution that reflect the corresponding mechanical decoupling/coupling along the northern Neo-Tethyan plate margin.  相似文献   
34.
Thin section, SEM, and TEM analyses have indicated that the red ‘teri’ sands of southeast India have formed from weathering in situ of coastal dune sands. The data does not support a detrital origin for the red sands. C14 dates indicate that dune deposition and weathering, to a maximum depth of 10 m, leading to the formation of a hematite, koalinite and illite rich matrix has taken place rapidly over the past 25,000 years. It is postulated that garnet was a major source of hematite (ferric oxide).  相似文献   
35.
The Jianchang Basin is one of the main localities of the precious fossils of Jehol Biota in western Liaoning. The fossil-bearing horizons are mainly in the Yixian- and J iufotang formations. In the Weijialing-Yaolugou of southwest Jianchang Basin, many precious fossils have been found at Luojiagou Bed of the 2nd Member of the Yixian Formation and at Xidian Bed of the 1st member of the Jiufotang Formation. The geologic setting, sedimentary environment and paleogeography of the precious fossil-bearing beds were also studied.  相似文献   
36.
Co-genetic debrite–turbidite beds are most commonly found in distal basin-plain settings and basin margins. This study documents the geometry, architectural association and paleogeographic occurrence of co-genetic debrite–turbidite beds in the Carboniferous Ross Sandstone with the goal of reducing uncertainty in the interpretation of subsurface data in similarly shaped basins where oil and gas is produced.The Ross Sandstone of western Ireland was deposited in a structurally confined submarine basin. Two outcrops contain co-genetic debrite–turbidite beds: Ballybunnion and Inishcorker. Both of the exposures contain strata deposited on the margin of the basin. An integrated dataset was used to characterize the stratigraphy of the Ballybunnion exposure. The exposure is divided into lower, middle, and upper units. The lower unit contains laminated shale with phosphate nodules, structureless siltstone, convolute bedding/slumps, locally contorted shale, and siltstone turbidites. The middle unit contains co-genetic debrite–turbidite beds, siltstone turbidites, and structureless siltstone. Each co-genetic debrite–turbidite bed contains evidence that fluid turbulence and matrix strength operated alternately and possibly simultaneously during deposition by a single sediment-gravity-flow event. The upper unit contains thin-bedded sandy turbidites, amalgamated sandy turbidites, siltstone turbidites, structureless siltstone, and laminated shale. A similar vertical facies pattern is found at Inishcorker.Co-genetic debrite–turbidite beds are only found at the basin-margin. We interpret these distinct beds to have originated as sand-rich, fully turbulent flows that eroded muddy strata on the slope as well as interbedded sandstone and mudstone in axial positions of the basin floor forming channels and associated megaflute erosional surfaces. This erosion caused the axially dispersing flows to laterally evolve to silt- and clay-rich flows suspended by both fluid turbulence and matrix strength due to a relative increase in clay proportions and associated turbulence suppression. The flows were efficient enough to bypass the basin center/floor, physically disconnecting their deposits from coeval lobes, resulting in deposition of co-genetic debrite–turbidite beds on the basin margin. The record of these bypassing flows in axial positions of the basin is erosional surfaces draped by thin siltstone beds with organic debris.A detailed cross-section through the Ross Sandstone reveals a wedge of low net-to-gross, poor reservoir-quality strata that physically separates sandy, basin-floor strata from the basin margin. The wedge of strata is referred to as the transition zone. The transition zone is composed of co-genetic debrite–turbidite beds, structureless siltstone, slumps, locally contorted shale, and laminated shale. Using data from the Ross Sandstone, two equations are defined that predict the size and shape of the transition zone. The equations use three variables (thickness of basin-margin strata, thickness of coeval strata on the basin floor, and angle of the basin margin) to solve for width (w) and trajectory of the basinward side of the low net-to-gross wedge (β). Beta is not a time line, but a facies boundary that separates sandy basin floor strata from silty basin-margin strata. The transition zone is interpreted to exist on lateral and distal margins of the structurally confined basin.Seismic examples from Gulf of Mexico minibasins reveal a wedge of low continuity, low amplitude seismic facies adjacent to the basin margin. Strata in this wedge are interpreted as transition-zone sediments, similar to those in the Ross Sandstone. Besides defining the size and shape of the transition zone, the variables “w” and “β” define two important drilling parameters. The variable “w” corresponds to the minimum distance a well bore should be positioned from the lateral basin margin to intersect sandy strata, and “β” corresponds to the deviation (from horizontal) of the well bore to follow the interface between sandy and low net-to-gross strata. Calculations reveal that “w” and “β” are related to the relative amount of draping, condensed strata on the margin and the angle of the basin margin. Basins with shallowly dipping margins and relatively high proportions of draping, clay-rich strata have wider transition zones compared to basins with steeply dipping margins with little draping strata. These concepts can reduce uncertainty when interpreting subsurface data in other structurally confined basins including those in Gulf of Mexico, offshore West Africa, and Brunei.  相似文献   
37.
<正>The classification and phytogeny of the basal Vespina(=Orussoidea+Apocrita)are reconsidered based primarily on rich and well preserved material from the Middle Jurassic of Daohugou in Inner Mongolia,China. Comparatively smooth morphological transitions are traced from a Xiphydriidae-like ancestor toward Orussoidea via the Jurassic family Karatavitidae,and through Karatavitidae and the Jurassic and Early Cretaceous family Ephialtitidae independently to Stephanidae,to Evanioidea,and,via the extinct Jurassic Kuafuidae fam.nov.to the remaining Apocrita.New hypothesis is proposed concerning development of the characteristic wasp-waist of Apocrita,which is supposed to appear independently and in different ways in Evanioidea and in the rest of Apocrita.As a result,six infraorders are proposed for the suborder Vespina with the following taxonomic structure:infraorder Orussomorpha including the only superfamily Orussoidea(Karatavitidae+Paroryssidae + Orussidae),infraorder Stephanomorpha with the only superfamily Stephanoidea(Ephialtitidae+Stephanidae), infraorder Evaniomorpha with the only superfamily Evanioidea of traditional composition,infraorder Ceraphronomorpha with the superfamilies Ceraphronoidea s.str.and monotypical Megalyroidea and Trigonaloidea,and the infraorders Proctotrupomorpha,Ichneumonomorpha,and Vespomorpha of traditional composition.The family Kuafuidae is unplaced to infraorder because it is putatively paraphyletic with respect to Ceraphronomorpha,Proctotrupomorpha,Ichneumonomorpha and Vespomorpha.Described as new are Karatavites junfengi sp.nov,Praeratavites wuhuaensis sp.nov.,P.perspicuus sp.nov.,Postxiphydria daohugouensis gen.et sp.nov.,P.ningchengensis gen.et sp.nov.,Postxiphydroides strenuus gen.et sp.nov.,Praeratavitoides amabilis gen.et sp.nov.,Proapocrtius densipediculus sp.nov.,P.sculptus sp.nov.,P.longantennatus sp.nov., P.formosus sp.nov.,P.atropus sp.nov.,P.elegans sp.nov.,Stephanogaster pristinus sp.nov.,Asiephialtites lini sp. nov.,Praeproapocritus vulgatus gen.et sp.nov.,Sinaulacogastrinus solidus gen.et sp.nov.,Sinevania speciosa gen. et sp.nov.,Eonevania robusta gen.et sp.nov.,Kuafua polyneura gen.et sp.nov.(all from the Middle Jurassic of Daohugou),as well as Kuafuidae fam.nov.including Kuafua gen.nov.as well as Arthrogaster Rasnitsyn,1975,and Leptogastrella Rasnitsyn,1975 from the Upper Jurassic of Karatau in Kazakhstan.  相似文献   
38.
刘书会  高永进  王长轩 《地质论评》2014,60(5):1043-1050
针对红层划分对比所面临的难题,在充分吸收前人研究成果的基础上,将现有的多种分层方法相互整合,彼此约束和印证,形成了一套科学、便捷的技术方法,即"接触关系明顶底、岩电特征找界面、多元融合定方案、地震约束建格架"的综合地层划分对比技术。该方法针对红层的特殊性,根据岩电特征对干旱气候的响应变化,充分利用了测、录井资料纵向上的连续性优势(避免了取样分析的局限),以及地震资料横向上的优势,有效地解决了红层纵向划分、横向对比的难题,在济阳坳陷东营凹陷南坡始新统沙河街组、孔店组的应用取得了良好效果。该方法可为其它地区同类复杂地层划分对比提供技术支持。  相似文献   
39.
泰宁丹霞红层由铁钙质混合胶结的较松散固结红色砂砾岩构成,岩石胶结物中CaCO3含量较高,抗压强度极低、孔隙度和含水性均较高。当岩石遇水湿润或浸泡时,或者生物风化过程中受到各种动植物分泌的有机酸作用,岩石胶结物中CaCO3易溶解流失,促使丹霞红层进一步软弱松散。冬季水结冰之后体积会膨胀,所以岩层表面产生片状裂隙。通过裂隙的毛细管效应,孔隙-裂隙水由岩石内部向结冰的表面扩散,在表面张力作用下水呈表面积最小的球状。春季化冻时岩石沿球形片状裂隙自由剥落的片状风化,圆球形洞穴开始形成,随着四季交替,年复一年,间歇性结冰和融化过程,使得洞穴逐渐扩大,形成泰宁丹霞各种形态的洞穴奇观。  相似文献   
40.
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