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1.
Miguel Orozco Antonio M lvarez-Valero Francisco M Alonso-Chaves John P Platt 《Tectonophysics》2004,385(1-4):85-104
Detailed structural analysis of the Sierra de Lújar in the western Alpujarras region (Betic Cordilleras, S Spain), a very representative area of the terrain known as the Alborán Domain, has revealed the existence of a very large N-vergent recumbent syncline which involves the whole mountain massif and neighbouring areas. The Lújar syncline and, probably, the associated recumbent anticline which crops out southeast of Sierra de Lújar show a great variation in the orientation of the hinge line. Although having a curved shape, the hinge line is contained in a plane whose attitude coincides with the main attitude of the axial-plane crenulation foliation (Sc), suggesting that it is a sheath fold.The strongly deformed overturned limb of the syncline is cut by two low-angle normal faults displacing towards the north. Similarity in the kinematics between the faults and the fold, and the association between the faults and the high-strain zone in the overturned limb of the fold, suggest that they are related. Regional constraints on the age of the crenulation cleavage and the low-angle normal faults indicate that they formed during the early Miocene late-orogenic extensional event in the Alborán Domain.We propose an alternate explanation for the structure of the Alpujarras region in which the Lújar syncline forms part of a recumbent syncline–anticline pair that extends along much of the Alpujarride outcrop in the southern Betic Cordillera. In several places, the fold is disrupted by low-angle normal faults, and it is overlain by an upper Alpujárride extensional sheet mainly composed of medium- to high-grade metamorphic rocks. We suggest that all these structures arose from the extensional deformation under decreasing temperature conditions of a previously thickened and metamorphosed orogenic crust. 相似文献
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早中生代(晚印支-早燕山期)岳阳-赤壁断褶带位于江南造山带与中扬子前陆盆地交界地带.作者对该构造带进行了地表地质调查,以此为基础探讨了构造剖面结构及构造变形动力机制.岳阳-赤壁断褶带自南而北可分为岳阳-临湘基底滑脱-逆冲带,桃花泉-肖家湾盖层滑脱褶皱带,以及赤壁-嘉鱼前陆盆地断-褶-盆构造带.岳阳-临湘基底滑脱-逆冲带自南而北依次有郭镇向斜、官山背斜、临湘倒转向斜和聂市背斜,组成隔槽式褶皱组合.褶皱轴面多向南倾,褶皱变形面为南华系盖层与冷家溪群褶皱基底间的角度不整合面和顺界面的滑脱断裂面.桃花泉-肖家湾盖层滑脱褶皱带主要发育轴面南倾倒转褶皱,褶皱波长较小,卷入地层为南华系-志留系以及上石炭统-中三叠统沉积盖层.赤壁-嘉鱼前陆盆地断-褶-盆构造带以南倾蒲圻断裂(江南断裂)为南部边界,发育T3-J2前陆盆地沉积,带内褶皱与断裂卷入地层包括沉积盖层以及T3-J2地层:南部断裂与褶皱轴面南倾.北部轴面近直立.自南西至北东,研究区内构造线走向由EW向渐变为NEE-NE向.上述构造分带及变形特征反映出自南向北的运动指向,表明岳阳-赤壁断褶带具前陆冲断带构造性质.从断裂相关褶皱理论出发,以地表构造特征为依据,厘定了岳阳-赤壁地质剖面结构并进行了变形动力机制分析,认识如下:①自南而北、自下而上的多个滑脱层及其间的南倾逆断裂或断坡(主要为江南断裂)组成近似台阶状的逆冲断裂系统,从总体上控制了构造块体的滑移、逆冲以及相应的构造格架或变形分区.②郭镇向斜为基底滑脱褶皱,官山背斜具滑脱褶皱和断裂传播褶皱双重成因,聂市背斜为断裂转折褶皱;临湘向斜为受两侧背斜控制的被动向斜,由于弯滑褶皱作用在其两翼沿不整合界面形成滑脱断裂.③岳阳-临湘基底滑脱-逆冲带隔槽式褶皱的形成主要受控于褶皱基底的滑脱和基底整体的水平压缩,其形成机制类似于肿缩式褶皱.最后讨论认为湘东北-鄂东南地区不存在大规模、长距离的逆冲推覆构造. 相似文献
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A. J. Stewart 《Australian Journal of Earth Sciences》2013,60(2):205-211
Twenty‐four mineral separates from the Arunta Complex, four from the metamorphosed Heavitree Quartzite (White Range Quartzite), and one whole rock sample of metamorphosed Bitter Springs Formation, all from the western part of the White Range Nappe of the Arltunga Nappe Complex, and two samples from the autochthonous basement west of the nappe have been dated by the K‐Ar method. The samples from the basement rocks form two groups. Those in the southern or frontal part of the nappe are of Middle Proterozoic (Carpentarian) age (1660–1368 m.y.), determined on hornblende, biotite, and muscovite. In the northern or rear part of the nappe, all but one of the muscovite samples and two biotites are of Middle Silurian to Early Carboniferous age (431–345 m.y.); the remainder of the biotite dates range from 1775 to 548 m.y. (including the two samples from the autochthon), and two hornblendes gave dates of 1639 and 2132 m.y. respectively. All the muscovite samples from the Heavitree Quartzite, and the whole rock sample from the Bitter Springs Formation gave Early to Middle Carboniferous dates (358–322 m.y.). The findings support the identification of the White Range Quartzite as the metamorphosed part of the Heavitree Quartzite, which in turn supports the interpretation of the structure of the area as a large, basement‐cored fold nappe. In addition, they date the time of the Alice Springs Orogeny as pre‐Late Carboniferous, which agrees with fossil evidence from elsewhere in the area. The Alice Springs Orogeny was accompanied by widespread greenschist facies meta‐morphism that progressively metamorphosed the Heavitree Quartzite and Bitter Springs Formation, and retrogressively metamorphosed the Arunta Complex. However, the basement rocks in the southern part of the nappe escaped this metamorphism and retain a Middle Proterozoic age, thus dating the time of the Arunta Orogeny in this region as Carpentarian or older. 相似文献
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英吉苏中新生代凹陷是在古生代逆冲推覆构造背景之上发育起来的背驮式前陆盆地。盆地的沉积作用和变形作用严格受基底参与的逆冲断层的控制。中新生代构造由北向南可划分七个带：北部斜坡带；群克─新开屏背斜带；英北向斜带；阿拉干背斜带；英南向斜带；古城墟斜坡带和罗布庄断凸带。叠瓦式逆冲断层、冲起构造、构造三角带、断展褶皱和披覆构造是英吉苏凹陷的主要变形样式。自三叠纪以来，不同时期的沉积中心自造山带向前陆方向迁移。 中新生界变形的动力学和运动学是与塔里木板块南缘活动大陆边缘的板块拼贴事件和壳内拆离缩短作用有关。 相似文献
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库车前陆褶皱-冲断带前缘秋里塔格构造带发育大量盐构造,其类型丰富多样。根据野外露头、钻井和地震资料识别出的盐构造样式主要有盐推覆、盐枕、盐墙、盐焊接、鱼尾构造、盐撤凹陷、突发构造、断层传播褶皱、断层转折褶皱和三角带构造等。秋里塔格构造带盐构造变形表现出明显的分段差异变形特征,其中西段却勒地区以古隆起(盐下)—盐枕(盐层)—逆冲推覆构造(盐上)为主;中段西秋地区以构造斜坡(盐下)—盐墙(盐层)—断层传播褶皱、向斜(盐上)为主;东段东秋地区则以断层转折褶皱(盐下)—盐推覆(盐层)—断层传播褶皱(盐上)为主。造成这种盐构造分段差异变形的主要控制因素包括基底断裂、含盐层系、构造转换带和变形空间等方面的差异性,其中基底构造和含盐层系的差异性起主导作用。 相似文献
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老挝万象平原盐类矿床控矿构造研究 总被引：2，自引：0，他引：2
老挝万象平原盐类矿层赋存于古近纪古新统塔贡组中,主要含钾矿物为光卤石,少量钾石盐。成矿期塔贡组及盐类矿层主要受北西向的边界断裂及塔贡向斜控制;成矿期后盐类矿层主要受褶皱（盐向斜、盐背斜）控制。在盐类矿层沉积后,先在水平应力作用下形成宽缓褶皱。由于向斜部位相对沉降,沉积速度较快,盐类矿层上部的碎屑岩较厚;而背斜部位相对上升,其上沉积的碎屑岩较薄。盐类矿层与碎屑岩存在较大的密度差,加之向斜与背斜上部的碎屑岩厚度不同,背斜与向斜的盐类矿层之间产生"差异负载"。向斜部位的盐类矿层受到较大的载荷向背斜塑性流动,使背斜部位矿层增厚,形成盐背斜,而向斜部位的矿层厚度明显变小。盐背斜部位往往盐类矿层厚度巨大,埋藏浅,上覆地层常常缺失,甚至于盐背斜进一步发育使钾盐矿层刺穿上覆泥岩层而暴露于相对的淡水环境中而遭受溶蚀。 相似文献
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秦岭南缘大巴山褶皱－冲断推覆构造的特征 总被引：14，自引：0，他引：14
秦岭造山带南缘的大巴山巨型逆冲推覆构造主要是在秦岭造山带板块俯冲碰撞造山与中、新生代以来陆内造山过程中长期复合作用形成的。详细的室内外构造研究表明,巴山逆冲推覆构造可以巴山弧形断裂带为界划分为北大巴山逆冲推覆构造和南大巴山逆冲推覆构造。北大巴山自北而南依次由安康－武当推覆体、紫阳－平利推覆体、高桥－镇坪推覆体和高滩推覆体逆冲叠置而成。南大巴山则以镇巴－阳日断裂为界,分为北部的前陆冲断褶皱带和南部的前陆褶皱带。北大巴山主要是印支期碰撞造山作用和燕山期陆内逆冲推覆作用叠加改造的结果,南大巴山则主要是燕山期递进变形过程中的产物。构造变形北强南弱,北以冲断褶皱变形为特征,南以皱褶作用为主;北部褶皱紧闭复杂,向南渐变为宽缓的薄皮构造。逆冲作用在时序上具有由北向南扩展传递的特点。 相似文献
8.
R.W. Marjoribanks 《Tectonophysics》1976,33(1-2)
A major, linear, west-trending deformed zone (The Redbank Zone), 350 km long and up to 20 km wide, can be identified in the Arunta Block immediately north of the Amadeus Basin. The marked linearity of this zone and of the coincident gravity anomaly probably result from thrust-fault movement during the Carboniferous Alice Springs Orogeny. However, in the Ormiston area, there is evidence that the zone originated prior to 1070 m.y. and acted as a major crustal feature controlling the later orogenic event.The Alice Springs Orogeny affected the overlying Proterozoic and Lower Palaeozoic cover rocks as well as the Arunta Block basement. During the orogeny, steep north-dipping thrusts within the Redbank Zone were reactivated causing uplift to the north. These faults penetrated the Heavitree Quartzite—the basal unit of the cover sequence—to drive wedges of basement, with attached veneers of Heavitree Quartzite, for up to 20 km southward within the overlying Bitter Springs Formation. The nappes did not reach the surface or penetrate formations above the Bitter Springs. Accompanying nappe emplacement the Basin to the south rapidly deepened to receive a thick wedge of synorogenic molasse sediments.Gravity, sedimentary and structural features combine to suggest that the Alice Springs orogeny movements reached their maximum on the central part of the northern margin of the Amadeus Basin, in the Ormiston area. 相似文献
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准噶尔盆地南缘山前冲断带经历了多期叠加构造活动,构造变形特征复杂,对研究陆内造山变形机制具有重要意义。阿什里背斜处于北天山后方前陆部位,构造样式为分层滑脱变形体系控制的复式叠加背斜,垂向上包括浅层薄皮推覆构造系统和中深层复合构造楔系统。钻井和地震反射信息揭示,阿什里地区主要滑脱层为基底滑脱层,石炭系、二叠系泥岩层,中下侏罗统八道湾组、西山窑组煤层。阿什里背斜侏罗系底部不整合面受基底发育的叠加构造楔(由2~3个冲断席构成)控制,反冲断层之上石炭系-三叠系构成不对称背斜。阿什里西南大型石炭系推覆体之下发育泥盆系-石炭系组成的冲断席,构成(楔端点向上方突破的)构造楔。阿什里背斜北侧以一向斜与喀拉扎背斜过渡,指示冲断位移沿浅部滑脱层向北继续传播。阿什里及邻区发育的石炭系与三叠系-中下侏罗统不整合、二叠系内部不整合、二叠系与三叠系削截不整合、三叠系与侏罗系不整合、新近系与第四系不整合揭示了中-晚二叠世以来多期构造活动。其中,阿1井核部二叠系梧桐沟组之下钻遇的凝灰岩锆石SHRIMP U-Pb同位素分析结果显示其年龄为289.1±7Ma(95%置信度),指示了晚海西期的构造活动。根据阿什里地区地震剖面的精细构造几何学、运动学解析,结合关键不整合面,划分了5个关键构造演化期次:中二叠世阿什里西南逆冲推覆形成古隆起;晚二叠世-晚三叠世阿什里地区存在两期小规模冲断活动;侏罗纪整体稳定沉降或弱坳陷;白垩纪-古近纪多幕隆升构造活动使阿什里地区沿基底发育叠加构造楔;中新世北天山剧烈造山活动中阿什里基底构造楔向北突破形成阿克屯-喀拉扎背斜。 相似文献
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八里塘煤矿位于淮南复向斜内的谢桥向斜南翼,由于受区域推覆构造的影响,矿区总体构造呈轴向近东西的不对称倒转褶皱形态,其两翼倾向倾角变化剧烈。煤矿深部构造为逆冲推覆构造区,上覆系统由阜凤逆冲断层及其分支断层的推覆构造断夹块组成,下伏系统由淮南复向斜次级褶皱谢桥向斜南翼原地系统组成。经估算位于F2断层（阜凤逆冲断层）下盘至-1200m水平的13-1、11-2、8-2、8-1煤层累计资源量约8000万t。 相似文献
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乌鲁木齐山前坳陷逆断裂-褶皱带及其形成机制 总被引：66，自引：9，他引：57
乌鲁木齐山前坳陷位于天山新生代再生造山带北侧,南以准噶尔南缘断裂与天山相隔,内部发育了几排逆断裂 背斜带,每一排构造带又由多个逆断裂 背斜组成。最南的齐古逆断裂 背斜带形成于中生代末,其北的玛纳斯逆断裂背斜带包含霍尔果斯、玛纳斯和吐谷鲁逆断裂背斜,形成于上新世末、早更新世初,受上、下２ 个滑脱面和断坡的控制,形成上、下２ 个背斜。再向北的独山子逆断裂背斜带由独山子、哈拉安德和安集海逆断裂背斜组成,形成于早、中更新世之间,主逆断裂向下在８ ～９ ｋｍ 深处的侏罗系中变为近水平滑脱面。此外,在独山子和吐谷鲁背斜的西北和东北还分别发育有正在形成之中的西湖和呼图壁隆起。研究了这些逆断裂 背斜带的地表和深部的构造特征、二维和三维几何学及运动学后指出,它们是在天山向准噶尔盆地扩展过程中发育于近水平滑脱面和不同断坡上的断展褶皱,独山子和安集海逆断裂 背斜的水平缩短量分别为２ ９００ ,１ ３５０ ｍ ,缩短速率分别为３９７ ,１８７ ｍ ｍ／ ａ。霍尔果斯、玛纳斯、吐谷鲁逆断裂 背斜的水平缩短量分别为５ ９００ ,６ ５００ ,６ ０００ ｍ ,相应的缩短速率分别为２０２,２２３ ,２０６ ｍ ｍ／ａ,准噶尔南缘断裂和乌鲁木齐山前坳陷第四纪? 相似文献
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黄陵背斜的构造几何形态及其成因探讨 总被引：1，自引：0，他引：1
黄陵背斜位于扬子克拉通的东缘,其核部出露的崆岭群被认为是扬予克拉通的基底岩石,并成为华南地质学研究的热点地区。从区域上看,黄陵背斜紧邻江汉盆地,东西两侧分别是荆当盆地与秭归盆地,黄陵背斜和周缘盆地构成明显的隆起—坳陷相互对应的构造。详细的野外观察和构造几何学的剖析表明,黄陵背斜的两翼西陡东缓,构成不对称背形的穹隆构造。在穹隆形成过程中,相应的岩石变形以顺层滑脱及相关的褶皱和小规模的逆冲断层为主,在早三叠世薄层灰岩、志留纪龙马溪组页岩、奥陶纪灰岩、寒武纪炭质灰岩以及震旦纪陡山沱组薄层灰岩广泛发育,并具有垂向缩短的重力滑脱特点,构造叠加关系指示了其形成于晚侏罗—早白垩纪之间。在构造变形分析的基础上,并深入探讨了黄陵背斜成因的3种可能的动力学背景。 相似文献
15.
研究区位于滇黔北坳陷威信凹陷的中西部区域——川南低陡褶皱带南缘带,本文利用钻井、野外露头、区域地质等资料,对研究区龙马溪组页岩气基本地质特征进行了分析,并采用体积法对页岩气资源量进行了评价。研究成果表明,区内龙马溪组下段暗色页岩有机质含量及成熟度较高,有机质类型偏腐泥型;岩石脆性矿物含量高,物性一般,总含气量中等,总体与长宁、威远等邻区同层位产气页岩较为相似,并与北美主要产气页岩具有一定可比性。初步估算研究区龙马溪组页岩气资源量24871.8×10~8m~3,展现出良好的勘探前景,但受储层发育、保存条件等影响,页岩气资源分布严重不均,纵向上质量较好的页岩气资源主要集中在龙马溪组底部第1小层,平面上主要分布于研究区北部的川南低陡褶皱带内,该区内保存条件好的宽缓复向斜带和箱状背斜构造带是下步勘探的有利区。 相似文献
16.
鄂尔多斯北缘石合拉沟逆冲推覆构造的发现及意义 总被引：12，自引：0，他引：12
最近在包头市幅1／25万区域地质调查工作中，在黄河南部鄂尔多斯北缘隆起带中发现了由北向南逆冲的石合拉沟推覆构造。上盘逆冲推覆体由基底浅变质的石英岩、黑云变粒岩和大理岩构成，推覆在晚石炭统太原组和中三叠统二马营组之上。野外地质关系表明逆冲推覆变形作用发生在晚侏罗世，与河套新生代断陷盆地北缘大青山逆冲推覆构造晚期逆冲推覆变形作用是同时的，逆冲推覆方向相反，构成了以现代河套盆地为中心的晚侏罗世背冲型逆冲推覆构造。该逆冲推覆构造的发现对探讨华北地台北缘中生代地壳构造变形特点和新生代河套断陷盆地基底构造性质具有重要意义。 相似文献
17.
羌塘盆地南羌塘坳陷地表古油藏作为了解盆地石油地质条件的良好窗口,经过多年来对古油藏详细解剖,通过详细的地表构造填图、二维地震和地质浅钻综合揭示了盆地存在大量的逆冲推覆构造。古油藏为盆地自北向南逆冲推覆至地表的大型构造岩席,主要表现为中生代海相地层推覆至晚白垩—中新世湖湘红层之上,古油藏含油层位是中侏罗布曲组砂糖状含油白云岩。针对古油藏石油地质条件解剖表明逆冲推覆构造虽然破坏了上坪油气藏,但是该构造活动不但能够使地层增厚利于有效烃源岩二次生烃,并对下坪地层有效遮挡封盖,同时构造活动有利于优质白云岩储集层和构造圈闭的形成,为二次成藏创造了良好的生储盖时空匹配关系,有利于逆冲推覆型油气藏的形成。 相似文献
18.
Fission-track thermochronology applied to the nappe pile of the Calabrian Arc of southern Italy, particularly within the continental basement rocks, has provided important new constraints on the nature of some of the tectonic contacts. In southern Calabria an important phase of lower Miocene crustal extension is indicated. In northern Calabria no Oligocene or younger extension is seen. Here, the emplacement of continental basement rocks with Alpine metamorphism over ophiolitic rocks with little or no metamorphism is constrained as a thrust of lower to middle Miocene age related to collision of the Calabrian Arc with the Adria plate margin. It is proposed that reduction in the plate convergence velocity during collision of a retreating subduction zone with a continental margin is, at least partly, an explanation for the onset of extension in southern Calabria during the Miocene. 相似文献
19.
Charles M. Onasch 《Tectonophysics》1984,110(1-2)
Compression and extension axes are deduced from quartz deformation lamellae in a quartzite and a graywacke folded into an asymetrical syncline. Deformation lamellae fabrics in the two sandstones are distinctly different. In the graywacke, regardless of bedding orientation or position on the fold, compression axes are normal or nearly normal to the axial planar rough cleavage. Extension axes generally lie in the cleavage plane, parallel to dip. In most quartzite samples, compression axes are parallel or subparallel to bedding, at high angles to the fold axis and extension axes are normal to bedding. Two samples from the very base of the formation indicate compression parallel to the fold axis with extension parallel to bedding, at high angles to the fold axis. One of these two shows both patterns. The lamellae fabric geometry in these two samples suggests the presence of a neutral surface in the quartzite. The lamellae-derived compression and extension axes are in good agreement with the buckling behavior of a viscous layer (quartzite) embedded in a less viscous medium (graywacke and shale below and shale and carbonate above). 相似文献
20.
通过野外构造变形解析得出,江西上饶船坑—铜山一带铜矿床及其相关的侵入岩体主要受中生代推覆构造控制。推覆构造面总体倾向SE,表现为波状起伏。推覆构造外来岩系为中石炭统至上三叠统碳酸盐岩及页岩、泥质粉砂岩,原地岩系为下侏罗统地层。外来岩系变形大多呈同斜褶皱,并伴生不同规模逆冲断层及顺层滑脱构造,局部存在平卧及箱状褶皱; 原地岩系变形亦较强烈。推覆构造表现为自SE向NW的运动。成矿岩体大多呈相互平行的薄层状,岩席侵位于上述推覆体外来岩系顺层滑脱带中。岩石地球化学及同位素年代学分析表明成矿岩体具挤压机制下岩浆弧特征,形成于170 Ma。结合推覆构造卷入的地层、研究区外围德兴一带同类型侵入岩与中生代推覆构造关系的讨论,认为上饶船坑—铜山一带与铜多金属矿相关的中生代石英二长斑岩为受同时代推覆构造变形控制的同构造岩浆岩,可能与中生代古太平洋板块向中国东南大陆俯冲导致岩石圈增厚发生大规模推覆构造,并诱发下地壳重熔岩浆侵位至浅表顺层滑脱空间有关。 相似文献