南秦岭古生代沉积盆地构造活动-海平面变化与沉积响应

位于扬子地台北部被动边缘的南秦岭镇安、旬阳古生代沉积盆地,发育一套早古生代—中生代一套碳酸盐岩夹细碎屑岩沉积,其沉积建造稳定,岩相清晰,地层层序及沉积体系域发育清楚,海平面变化敏感,是研究海平面变化与沉积响应较理想的地区。通过对区内沉积盆地地层特征及侧向变化分析,初步划分出了10个层序,识别出若干个沉积体系域和层序界面。盆地沉积演化与构造体制、区域性构造运动密切相关,构造活动控制了海平面变化。通过区域地层格架分析和层序地层学研究,可以进一步研究区域构造活动历史,恢复海平面变化细节,建立岩石地层、年代地层格架,从微观上准确了解区域海平面敏感变化,确切刻画古气候、古地理、古环境,从而更好的预测沉积矿产。     

大型陆相坳陷型沉积盆地原型恢复方法——以新生代柴达木盆地为例

陆相坳陷型沉积盆地通常发育在克拉通的内部差异沉降和裂谷盆地后期的热沉降等不同的大地构造阶段,是一类独特而又十分重要的沉积盆地。本文基于该类盆地的特点,提出了综合利用盆地沉积相、残余厚度图、区域构造大剖面及其平衡恢复等多方面资料对其盆地原型进行恢复的方法和流程,具体包括以残余沉积相恢复盆地原始边界、以平衡剖面恢复盆地原始形态、以关键钻井资料与平衡剖面相结合恢复原始沉积厚度。该方法消除了构造运动对盆地形态的改变,真正将盆地原型纳入到其原始形态框架下进行研究。本文还利用该方法对柴达木盆地新生代各地层沉积时的盆地原型分别进行了恢复,并据此对其新生代的沉积演化进行了分析,结果表明柴达木盆地新生代的沉积格局变化与阿尔金断裂的活动息息相关。     

沉积盆地沉积－剥蚀过程定量研究的一种新方法──盆地波动分析应用之一

本文在概述了确定剥蚀厚度方法基础上，提出了沉积盆地沉积－剥蚀过程定量研究的一种新方法──盆地波动过程分析法。该方法从钻井地层厚度资料入手，通过沉降史的研究，恢复地层的原始沉积厚度，结合各组段地层年代框架的标定，计算出各组段的沉积速率，引入数理方法建立盆地演化的波动方程。并进行剖面和平面上的分析对比，实现对沉积－剥蚀过程的定量预测。     

沉积盆地沉积－剥蚀过程定量研究的一种新方法──盆地波动分析应用之一

本文在概述了确定剥蚀厚度方法基础上，提出了沉积盆地沉积－剥蚀过程定量研究的一种新方法──盆地波动过程分析法。该方法从钻井地层厚度资料入手，通过沉降史的研究，恢复地层的原始沉积厚度，结合各组段地层年代框架的标定，计算出各组段的沉积速率，引入数理方法建立盆地演化的波动方程。并进行剖面和平面上的分析对比，实现对沉积－剥蚀过程的定量预测。     

皖南东至地区寒武系层序地层研究

皖南东至地区寒武系在地层分区上可以分为下扬子地层分区、过渡地层分区和江南地层分区，生物群上出现了两区特征分子和过渡区的混生现象，并处于台地与盆地交接部位。通过对分别位于台地、斜坡和盆地露头层序地层研究，将寒武纪地层自下而上划分为三个Ⅱ类沉积层序和二个Ⅰ类沉积层序，早寒武世的三个Ⅱ类沉积层序的陆架边缘体系域不发育；中寒武世晚期到晚寒武世的二个Ⅰ类沉积层序皆由低水位体系域、海侵体系域和高水位体系域 组成三元结构。通过层序地层分析和沉积体系演化建立了相应的海平面变化曲线，自早寒武世早期本区海平面达到最高位和最大上升速率后，至寒武纪末研究区海平面总体处于下降过程，即海平面为累进式的缓慢的下降。     

鄂尔多斯盆地早白垩世剥蚀地层厚度恢复研究

鄂尔多斯盆地下白垩统为中生代盆地演化末期最晚沉积的地层,也是自鄂尔多斯盆地发育以来后期遭受剥蚀改造最为强烈的地层,残存范围最小。通过对全盆八百二十余口钻井现存中生代地层厚度及岩性的统计,从中选取了313口井读取声波时差值,采用声波时差和地层对比趋势法相结合进行剥蚀厚度估算,同时利用联井剖面对比法对整个盆地的恢复厚度进行对比验证。在此基础之上,恢复了早白垩世盆地原始沉积厚度,初步探讨了盆地原始沉积面貌,基本确定了盆地原始沉积边界,从而进一步加深了对晚白垩世以来盆地强烈构造变动的认识,对多种能源矿产同盆共存富集规律的研究具一定的启示。     

扬子地台北缘南郑马元—宁强阳平关沉积盆地沉积构造事件与海平面变化响应

位于扬子地台北部被动边缘的南秦岭南郑—阳平关一带古生代沉积盆地,发育一套早古生代—中生代碳酸盐岩夹细碎屑岩沉积,沉积构造及岩相清晰。通过对区内沉积盆地地层特征及侧向变化分析,初步划分出了6个层序,识别出若干个沉积体系域和层序界面。盆地沉积演化与构造体制、区域性构造运动密切相关,构造活动控制了海平面变化。近几年来,在南郑马元一带震旦系灯影组白云岩中,发现了近百千米的马元型铅锌矿带,因此,通过区域地层格架分析和层序地层学研究,进一步研究区域构造活动历史,恢复海平面变化细节,建立岩石地层格架,从微观上准确了解区域海平面敏感变化,从而更好地预测沉积矿产。     

含油气盆地剥蚀厚度恢复研究进展

地层剥蚀厚度恢复是含油气原始盆地恢复的重要内容,对定量研究盆地演化史意义重大.对利用地质判别推断、沉积速率与旋回、压实密度和热演化等四个方面的剥蚀厚度恢复方法进行了总结归纳,选取有代表性的方法进行探讨.通过比较,最后提出应根据研究区具体的地质特征选择适宜的方法,注意多种方法的综合运用来进行剥蚀厚度恢复.     

龙门山泥盆纪沉积盆地的古地理和古构造重建

位于扬子地块西缘的龙门山区,是著名的中生代冲断带,其中泥盆系发育,沉积类型多样,厚度巨大,既包括未经变质的稳定型,也包括浅变质的过渡型和活动型地层。根据推覆构造特点和不同类型泥盆系之间的关系,确认前山带、中山带和后山带,分别包含了泥盆纪沉积的边缘带、过渡带和活动带的地层纪录。泥盆纪的沉积盆地则是一个NE向不对称的裂谷盆地,它的东南边缘,早期由于同生断裂的影响造成宽阔而复杂的古地理面貌和岩相、厚度变化。晚期由于海平面上升,沉积区扩大,边缘带成为宽阔平坦的碳酸盐台地,北段仍保留平行岸线的深水槽地,盆地西侧为较深水的浊积岩分布区,而后过渡为边缘浅水区。本区泥盆系的层序地层结构特点,是由多级不对称层序组成,沉降曲线则由两个下凹的曲线组成阶梯状。这些特点说明,该盆地具有伸展成因的裂谷性质,盆地的形成可能与沿着有根的叠瓦式低角度剪切断裂系发育的地壳伸展作用有关。     

贵州省黔北煤田含煤地层特征分析

黔北煤田是贵州省主要产煤区之一,大地构造位置处于扬子陆块南部被动边缘褶冲带上的毕节弧形构造区、织金宽缓褶皱区和凤冈南北向褶断区,主要含煤地层为上二叠统龙潭组和长兴组。含煤层数多、厚度大,含煤性由南西至北东逐渐变差。玄武岩的间歇性喷溢对含煤地层的沉积基底填平补齐,提供了良好的聚煤环境;海平面频繁升降引起海水反复性进退,促进了多煤层发育。晚二叠世海陆过渡相沉积受河流与海洋双重作用,由西向东发育三角洲平原、潟湖—潮坪、碳酸盐台地相沉积,前两者沉积类型煤层发育相对较好。聚煤作用整体以由东向西的超覆式海进成煤为主,海退型成煤次之。富煤带的纵横迁移,受控于海水进退下的古地理环境的时空变化。     

利用上超点法重建渤海湾盆地辽中凹陷渐新世湖平面变化

标准层序是指同时包含高位体系域HST、湖侵体系域TST、下降体系域FSST和低位体系域LST的三级层序。通过对标准三级层序各类体系域中上超特征的分析,将一个标准层序的上超点分为5大类,即LST上超点、TST上超点、早期HST上超点、晚期HST上超点和FSST上超点,提出了通过统计层序内各类上超点来反演湖平面变化史的方法...     

Syntectonic unconformities of the Alto Cardener,Spanish Pyrenees: a genetic interpretation

The age of three syntectonic unconformities belonging to the Upper Eocene—Middle Oligocene is discussed. The structural characteristics of the conglomerates in the Catalonian south Pyrenees are described with special attention to mechanisms of tectonics and sedimentation and to the lateral relationships between conformity, progressive unconformity (or cumulative wedge system) and angular unconformity. The older unconformities have been tectonically deformed. A new genetic model is proposed to explain offlaponlap mechanisms of each folding phase and the development of angular and progressive unconformities.     

不整合分析及其在陆相盆地构造研究中的意义

讨论了3个问题,即不整合分析及其在研究陆相盆地的形成和演化中的意义;不整合分析及其与构造运动和盆地改造的关系;与不整合有关的圈闭类型。通过上述的不整合分析,可以获得以下结论：正旋回地层的超覆(或上超)是在拉张或中性构造背景中产生的,而反旋回地层的退覆和削截一不整合则是在挤压构造环境中发育的;复合递进型同构造不整合与内陆前陆盆地边缘挤压隆起的加速和减速上升有关。根据不整合面下被削截岩层的构造变形和侵蚀厚度可以推断出由构造运动所造成的盆地改造程度和与不整合有关的地层圈闭类型。     

Sequence stacking patterns in the Western Canada foredeep: influence of tectonics, sediment loading and eustasy on deposition of the Upper Cretaceous Kaskapau and Cardium Formations

The Kaskapau and Cardium Formations span Late Cenomanian to Early Coniacian time and were deposited on a low‐gradient foredeep ramp. The studied portion of the Kaskapau Formation spans ca 3·5 Myr and forms a mudstone‐dominated wedge thinning from 700 to <50 m from SW to NE over ca 300 km. In contrast, the Cardium Formation spans about 2·1 Myr, is about 100 m thick, sandstone‐rich and broadly tabular. The Kaskapau and Cardium Formations are divided, respectively, into 28 and nine allomembers, each bounded by marine flooding surfaces. Kaskapau allomembers 1 to 7 show about 200 km of offlap from the forebulge, accompanied by progradation of thin sandstones from the eroded forebulge crest. In contrast, Kaskapau allomembers 8 to 28 and Cardium allomembers C1 to C9 show overall onlap onto the forebulge of about 350 km, and contain no forebulge‐derived sandstones. This broad pattern is interpreted as recording a latest Cenomanian pulse of tectonic loading which led to shoreline back‐step in the proximal foredeep and coeval uplift of the forebulge, leading to erosion. The advance of the sediment wedge after Kaskapau allomember 7 is attributed primarily to the isostatic effect of a distributed sediment load; the advance of the orogenic wedge had a subordinate effect on subsidence of the forebulge. For Kaskapau allomembers 1 to 6, isopachs trend north to south, suggesting a load directly to the west; allomembers 7 to 28 show an abrupt rotation of isopachs to NW–SE, suggesting that the load shifted several hundred kilometres to the south. This re‐orientation might be related to a change from an approximately orthogonal to a dextral transpressive stress regime. Within the longer‐term offlap–onlap cycle recorded by the Kaskapau and Cardium Formations, individual allomembers are grouped into packages reflecting higher‐frequency onlap–offlap cycles, each spanning ca 0·5 to 0·7 Myr. Offlap from the forebulge tends to be accompanied by more pronounced transgression in the foredeep, whereas onlap onto the forebulge is accompanied by progradation of tongues of shoreface sandstone. This relationship suggests that changes in deformation rate in the orogenic wedge modulated proximal subsidence rate, enhancing or suppressing shoreline progradation, and also causing subtle uplift or subsidence of the forebulge region. Wedge‐shaped allomembers in the Kaskapau Formation contain shoreface sandstone and conglomerate that prograded, respectively, <40 and <25 km from the preserved basin margin; progradation of coarse clastics was limited by rapid flexural subsidence. Tabular allomembers of the Cardium Formation imply a low flexural subsidence rate and contain sandy and conglomeratic shoreface deposits that prograded up to ca 180 km from the preserved basin margin. This relationship suggests that low rates of flexural subsidence promoted steeper alluvial gradients, more vigorous gravel transport and more extensive shoreface progradation. Overall, observed stratal geometry and facies distribution is explained readily in terms of current elastic flexural models. Most shoreface sandstones in the proximal foredeep show evidence of forced regression. Eustasy provides the most plausible explanation for relative sea‐level rise–fall cycles on the 125 kyr allomember timescale. Geometric relationships suggest eustatic oscillations of about 10 m. Forced regressive shoreface development was suppressed during Kaskapau allomembers 1 to 10 when the rate of flexural subsidence was at its highest.     

塔里木盆地北部古生界密集段分布型式与海平面变化的关系

塔里木盆地北部震旦纪－古生代层序地层格架中,发育着６个可作为生油层的大型密集段或复合密集段。密集段在层序格架中有４种叠置型式,即进积组合,退积组合,加积组合和上超组合。不同的叠置型对应于不同的海平面变化过程。相应地,密集段的发育规模及时空展布有着明显的差别,其中,在退积层序组合和进积层序组合中,密集段垂向上相互叠置,侧向上彼此邻接,构成层数与厚度复杂多变的复合密集段,是盆地中的主力生油层。     

浅海海底表层速度建模技术及其应用研究

浅海海底起伏和速度变化对OBC资料成像质量产生较大影响。建立浅海海底表层速度模型不仅能够解决OBC资料的静校正问题,也可用于海底反射系数计算、双检资料合并、多次波压制等,但是,目前针对浅海海底表层速度建模的研究还不多。文中提出了针对浅海地区OBC资料的海底表层速度建模的三维初至走时反演技术,主要包括:(1)震源位置校正技术。根据地震波在海水中传播特征,把在海水中激发的震源位置校正至海底,使震源和接收点都位于海底,利于初至走时反演计算;(2)快速三维初至走时反演方法。利用回折波走时和射线方程,形成了高效率初至走时反演方法。将该技术应用于胜利油田莱州湾浅海区海底OBC资料的处理中,建立了三维海底表层速度模型,用此速度模型进行静校正,取得了良好的应用效果。     

Internal anatomy of a mixed siliciclastic–carbonate platform: the Late Cenomanian–Mid Turonian at the southern margin of the Spanish Central System

The Late Cenomanian–Mid Turonian succession in central Spain is composed of siliciclastic and carbonate rocks deposited in a variety of coastal and marine shelf environments (alluvial plain–estuarine, lagoon, shoreface, offshore‐hemipelagic and carbonate ramp). Three depositional sequences (third order) are recognized: the Atienza, Patones and El Molar sequences. The Patones sequence contains five fourth‐order parasequence sets, while a single parasequence set is recognized in the Atienza and El Molar sequences. Systems tracts can be recognized both in the sequences and parasequence sets. The lowstand systems tracts (only recognized for Atienza and Patones sequences) are related to erosion and sequence boundary formation. Transgressive systems tracts are related to marine transgression and shoreface retreat. The highstand systems tracts are related to shoreface extension and progradation, and to carbonate production and ramp progradation. Sequences are bounded by erosion or emergence surfaces, whose locations are supported by mineralogical analyses and suggest source area reactivation probably due to a fall in relative sea‐level. Transgressive surfaces are subordinate erosion and/or omission surfaces with a landward facies shift, interpreted as parasequence set boundaries. The co‐existence of siliciclastic and carbonate sediments and environments occurred as facies mixing or as distinct facies belts along the basin. Mixed facies of coastal areas are composed of detrital quartz and clays derived from the hinterland, and dolomite probably derived from bioclastic material. Siliciclastic flux to coastal areas is highly variable, the maximum flux postdates relative sea‐level falls. Carbonate production in these areas may be constant, but the final content is a function of changing inputs in terrigenous sediments and carbonate content diminishes through a dilution effect. Carbonate ramps were detached from the coastal system and separated by a fringe of offshore, fine‐grained muds and silts as distinct facies belts. The growth of carbonate ramp deposits was related to the highstand systems tracts of the fourth‐order parasequence sets. During the growth of these ramps, some sediment starvation occurred basinwards. Progradation and retrogradation of the different belts occur simultaneously, suggesting a sea‐level control on sedimentation. In the study area, the co‐existence of carbonate and siliciclastic facies belts depended on the superimposition of different orders of relative sea‐level cycles, and occurred mainly when the second‐order, third‐order and fourth‐order cycles showed highstand conditions.     

Application of sequence and genetic stratigraphic concepts to Carboniferous coal-bearing strata: an example from the Black Warrior basin,USA

Carboniferous strata provide an excellent example on which to test the application of genetic stratigraphic and sequence stratigraphic concepts. Both approaches are employed in the evaluation of the coal-bearing strata of the Black Warrior basin, south-eastern USA. Bounding hiatal surfaces have been recognized in the succession of rock that includes the Mary Lee coal zone. Within the framework of genetic stratigraphy, one genetic sequence has been identified comprised of offlap (progradational and aggradational facies) and onlap (aggradational and transgressive facies) components. Seven parasequence sets have been delimited according to the concepts of sequence stratigraphy. These have been ascribed to transgressive, highstand and shelf margin systems tracts. The identification of components of these contrasting frameworks provide the basis for evaluating other Carboniferous strata. Correspondence to: R. A. Gastaldo     

塔里木盆地寒武系层序界面特征及其油气地质意义

以塔里木盆地寒武系为研究对象,通过对盆地西北缘柯坪塔格地区、东北缘库鲁克塔格地区及西南缘寒武系野外剖面详细观测及盆内TS1井,YQ6井等钻井岩心详细观察,根据各类测试分析成果,共识别出6种类型的层序界面,它们分别是:①古风化壳.②渣状层,③古喀斯特作用面,④超覆面,⑤岩性、岩相转换面,⑥最大海泛面.在各类层序界面特征详细研究基础上,将上述界面归结为4种成因类型,分别是:造山侵蚀层序不整合界面,隆升侵蚀层序不整合界面,海侵上超层序不整合界面和陆上暴露层序不整合界面.层序界面成因类型不仅反映了海平面升降速度与构造沉降的耦合关系,而且还反映这两者耦合作用之下形成的物质响应和它们两者之间的本质差别,以及形成这些差别的盆地性质及动力学机制.最后,根据层序界面特征及成因意义,详细论述了层序界面的研究意义,具体表现为:(1)反映盆地性质与演化;(2)控制储层的发育,包括控制岩溶储层和白云岩储层的发育;(3)控制油气的运移;层序界面与裂缝、断裂共同组成了沟通孔隙流体流动的输导系统.     

塔里木盆地北部寒武纪海平面变化研究

在以往的沉积学研究中，常常用剖面中的相对水深变化来讨论海平面的变化规律。本文通过对塔里木盆地北部寒武纪上超点变化曲线与肖尔布拉克地区寒武系露头剖面中相对水深变化曲线的对比研究发现，上超点变化曲线与相对水深变化曲线具有明显的差异，前者在寒武纪呈持续上升趋势，而后者除早期有一快速上升外，总体呈持续下降趋势，这说明相对水深变化虽与海平面变化存在着本质的联系，但单凭露头剖面中相对水深变化的研究是难以对海平面变化作出正确估价的，还必须综合考虑基底沉降、沉积物供给等多种因素的影响。计算机模拟结果也证实了，在碳酸盐台地的浅水处，当基底沉降速率较低时，无论是海平面上升还是下降时期，相对水深均呈现持续下降趋势。为了能从露头剖面的地层层序中来了解海平面的变化规律，本文应用作者改进后的Ｆｉｓｃｈｅｒ图解和数学方法对肖尔布拉克寒武系剖面进行了海平面变化的重建，结果发现，它们与上超点变化曲线的变化趋势完全一致。这充分说明了海平面变化对沉积层序的控制作用，同时也告诉我们，不能简单地利用露头剖面中的相对水深变化来研究地质历史时期的海平面变化规律。只有在排除了不同沉积背景上基底沉降速率和沉积物供给速率对沉积层序的控制效应后，才能从露头剖面?