郯庐断裂南段研究进展与断裂性质讨论

据1：5万区域地质调查和专题研究资料，就郯庐断裂带是否南延与消失的原因，其与大别—苏鲁造山带交截形成的假位错效应，以及与中新生代沉积盆地形成演化的关系等作了新的阐述。在此基础上，讨论了郯庐断裂带是否为巨大的左行平移断层或转换断层。认为郯庐断裂带可能是在“古郯庐带”的基础上于早侏罗世重新活动、白垩纪强烈活动的地堑型枢纽断裂带。     

龙门山地区关口断裂形成与演化分析

根据大量野外露头剖面资料与钻井数据,系统分析了关口断裂形成过程与演化特征。认为关口断裂在印支早、中期为张性大力构造背景下形成的同沉积正断层,在晚三叠世卡尼克期为生长性正断层;印支晚期构造事件中该断裂改变为逆冲断层。关口断裂活动性较强,其中在燕山晚期活动性最强。关口断裂在喜马拉雅期有多期次的、长时期的强烈活动;并且目前仍是一条活动性的断层。     

Fault-Growth Pattern of the South Margin Normal Fault of the Yuguang Basin in Northwest Beijing and its Influencing Factors

Based on high-resolution remote sensing image interpretation, digital elevation model 3-D analysis, field geologic field investigation, trenching engineering, and ground-penetrating radar, synthetic research on the evolution of the Yuguang Basin South Margin Fault (YBSMF) in northwest Beijing was carried out. We found that the propagation and growth of faults most often occurred often at two locations: the fault overlapping zone and the uneven or rough fault segment. Through detailed observation and analysis of all cropouts of faults along the YBSMF from zone a to zone i, we identified three major factors that dominate or affect fault propagation and growth. First, the irregularity of fault geometry determine the propagation and growth of the fault, and therefore, the faults always propagate and grow at such irregular fault segments. The fault finally cuts off and eliminates its irregularity, making the fault geometry and fault plane smoother than before, which contributes to the slipping movement of the half-graben block in the basin. Second, the scale of the irregularity of the fault geometry affects the result of fault propagation and growth, that is, the degree of the cutting off of fault irregularity. The degree of cutting off decreases as irregularity scale increases. Third, the maximum possible slip displacement of the fault segment influences the duration of fault propagation and growth. The duration at the central segments with a large slip displacement is longer than that at the end segments with a smaller slippage value.     

丽江-小金河断裂盐源段断裂带规模、断裂带结构及其历史活动性

2008年汶川地震促使人们思考青藏高原东南缘走向和规模与龙门山断裂带相近的丽江- 小金河断裂的活动历史,但受限于地质条件制约断裂尤其是其北段相关研究极其薄弱。基岩断裂带的物质组成与结构特征是断层长期活动的产物,蕴含丰富的历史活动信息。本文以丽江- 小金河断裂盐源段多个天然剖面为研究对象,通过详细的断裂带宏观结构调查、断层岩显微构造及XRD分析发现：① 断层破碎带以一套厚度>20 m的破裂面密集带为特征,优势破裂面走向为NE20°~30°,推测为丽江- 小金河断裂长期活动形成的张剪性破裂;② 断层带核部以断层角砾岩和断层泥为主,灰岩角砾岩黏土矿物含量~2%,以伊利石和伊蒙混层为主,粉砂岩断层泥黏土矿物含量~52%,以坡缕石和绿泥石为主,石英含量36%,缺失长石类矿物。断裂带宏观结构和断层岩微观结构特征均表现为角砾呈棱角状,砾径差异极大且呈零散状分布,符合快速滑动特征,指示断层滑移方式为黏滑。此外,核部断层岩带统计厚5~8 m,这一规模相对于龙门山映秀- 北川断裂带核部180~280 m和安县- 灌县断裂带核部40~50 m显著偏小,表明前者自形成以来的活动性远低于后者,两者的地震行为并不能简单类比。结合断裂在宏观结构特征、断层岩成分与种类以及所反映的滑动方式与隆升剥蚀量的差异,认为丽江- 小金河断裂更可能是鲜水河断裂切断锦屏山- 龙门山构造带之后形成的,晚新生代与龙门山断裂带具有不同的活动历史。     

Relationship between the Pre-existing Active Kunlun Fault and Co-seismic Surface Ruptures Produced by the 2001 Mw 7．8 Central Kunlun Earthquake，China

Field investigations allow to constrain the co-seismic surface rupture zone of ～400km with a strike-slip up to 16．3 m associated with the 2001Mw 7．8 Central Kunlun earthquake that occurred along the western segment of the Kunlun fault,northern Tibet．The co-seismic rupture structures are almost duplicated on the pre-existing fault traces of the Kunlun fault．The deformational characteristics of the co-seismic surface ruptures reveal that the earthquake had a nearly pure strike-slip mechanism．Theg eologic and topographice vidence clearly shows that spatial distributions of the co-seismic surface ruptures are re-stricted by the pre-existing geological structures of the Kunlun fault．     

Salinia revisited: a crystalline nappe sequence lying above the Nacimiento fault and dispersed along the San Andreas fault system,central California

Salinia, as originally defined, is a fault-bounded terrane in westcentral California. As defined, Salinia lies between the Nacimiento fault on the west, and the Northern San Andreas fault (NSAF) and the main trace of the dextral SAF system on the east. This allochthonous terrane was translated from the southern part of the Sierra Nevada batholith and adjacent western Mojave Desert region by Neogene-Quaternary displacement along the SAF system. The Salina crystalline basement formed a westward promontory in the SW Cordilleran Cretaceous batholithic belt, relative to the Sierra Nevada batholith to the north and the Peninsular Ranges batholith to the south, making Salinia batholithic rocks susceptible to capture by the Pacific plate when the San Andreas transform system developed. Proper restoration of offsets on all branches of the San Andreas system is a critical factor in understanding the Salinia problem. When cumulative dextral slip of 171 km (106 mi) along the Hosgri–San Simeon–San Gregorio–Pilarcitos fault zone (S–N), or dextral slip of 200 km (124 mi) along the Hosgri–San Simeon–San Gregorio–Pilarcitos–northern San Andreas fault system, is added to the cumulative dextral slip of 315–322 km (196–200 mi) along the main trace of the SAF north of the San Emigdio–Tehachapi mountains, central California, there is a minimum amount of cumulative dextral slip of 486 km (302 mi) or a maximum amount of cumulative dextral slip of 522 km (324 mi) along the entire SAF system north of the Tehachapi Mountains. When these sums are compared with the offset distance (610–675 km or 379–420 mi) between the batholithic rocks associated with the Navarro structural discontinuity (NSD) in northern California, and those in the ‘tail’ of the southern Sierra Nevada granitic rocks in the San Emigdio–Tehachapi mountains, central California, a minimum deficit of from ～100 km (～62 mi) to a maximum deficit of ～189 km (～118 mi) is needed to restore the crystalline rocks associated with the NSD with the crystalline terranes within the San Emigdio and Tehachapi mountains – the enigma of Salinia. Two principal geologic models compete to explain the enigma (i.e. the discrepancy between measured dextral slip along traces of the SAF system and the amount of separation between the Sierra Nevada batholithic rocks near Point Arena in northern California and the Mesozoic and older crystalline rocks in the San Emigdio and Tehachapi mountains in southern California). (i) One model proposes pre-Neogene (>23 Ma), Late Cretaceous or Maastrichtian (<ca. 71 Ma) to early Palaeocene or Danian (ca. 66 Ma) sinistral slip of 500–600 km (311–373 mi) along the Nacimiento fault and of the western flank of Salinia from the eastern flank of the Peninsular Ranges (sinistral slip but in the opposite sense to later Neogene (<23 Ma) dextral slip along and within the SAF system. (ii) A second model proposes that the crystalline rocks of Salinia comprise a series of 100 km- (60 mi-) scale allochthonous (extensional) nappes that rode southwestward above the Rand schist–Sierra de Salinas (SdS) shear zone subduction extrusion channels. The allochthonous nappes are from NW–SE: (i) Farallon Islands–Santa Cruz Mountains–Montara Mountain, and adjacent batholithic fragments that appear to have been derived from the top of the deep-level Sierra Nevada batholith of the western San Emigdio–Tehachapi mountains; (ii) the Logan Quarry–Loma Prieta Peak fragments that appear to have been derived from the top of a buried detachment fault that forms the basement surface beneath the Maricopa sub-basin of the southernmost Great Valley; (iii) The Pastoria plate–Gabilan Range massif that appears to have been derived from the top of the deep-level SE Sierra Nevada batholith; and (iv) the Santa Lucia–SdS massif, which appears to be lower batholithic crust and underlying extruded schist that were breached westwards from the central to western Mojave Desert region. In this model, lower crustal batholithic blocks underwent ductile stretching above the extrusion channel schists, while mid- to upper-crustal level rocks rode southwestwards and westwards along trenchward dipping detachment faults. Salinian basement rocks of the Santa Lucia Range and the Big Sur area record the most complete geologic history of the displaced terrane. The oldest rocks consist of screens of Palaeozoic marine metasedimentary rocks (the Sur Series), including biotite gneiss and schist, quartzite, granulite gneiss, granofels, and marble. The Sur Series was intruded during Cretaceous high-flux batholithic magmatism by granodiorite, diorite, quartz diorite, and at deepest levels, charnockitic tonalite. Local nonconformable remnants of Campanian–Maastrichtian marine strata lie on the deep-level Salinia basement, and record deposition in an extensional setting. These Cretaceous strata are correlated with the middle to upper Campanian Pigeon Point (PiP) Formation south of San Francisco. The Upper Cretaceous strata, belonging to the Great Valley Sequence, include clasts of the basement rocks and felsic volcanic clasts that in Late Cretaceous time were brought to a coastal region by streams and rivers from Mesozoic felsic volcanic rocks in the Mojave Desert. The Rand and SdS schists of southern California were underplated beneath the southern Sierra Nevada batholith and the adjacent Salinia-Mojave region along a shallow segment of the subducting Farallon plate during Late Cretaceous time. The subduction trajectory of these schists concluded with an abrupt extrusion phase. During extrusion, the schists were transported to the SW from deep- to shallow-crustal levels as the low-angle subduction megathrust surface was transformed into a mylonitic low-angle normal fault system (i.e. Rand fault and Salinas shear zone). The upper batholithic plate(s) was(ere) partially coupled to the extrusion flow pattern, which resulted in 100 km-scale westward displacements of the upper plate(s). Structural stacking, temporal and metamorphic facies relations suggest that the Nacimiento (subduction megathrust) fault formed beneath the Rand-SdS extrusion channel. Metamorphic and structural relations in lower plate Franciscan rocks beneath the Nacimiento fault suggest a terminal phase of extrusion as well, during which the overlying Salinia underwent extension and subsidence to marine conditions. Westward extrusion of the subduction-underplated rocks and their upper batholithic plates rendered these Salinia rocks susceptible to subsequent capture by the SAF system. Evidence supporting the conclusion that the Nacimiento fault is principally a megathrust includes: (i) shear planes of the Nacimiento fault zone in the westcentral Coast Ranges locally dip NE at low angles. (ii) Klippen and/or faulted klippen are locally present along the trace of the Nacimiento fault zone from the Big Creek–Vicente Creek region south of Point Sur near Monterey, to east of San Simeon near San Luis Obispo in central California. Allochthonous detachment sheets and windows into their underplated schists comprise a composite Salinia terrane. The nappe complex forming the allochthon of Salinia was translated westward and northwestward ～100 km (～62 mi) above the Nacimiento megathrust or Franciscan subduction megathrust from SE California between ca. 66 and ca. 61 Ma (i.e. latest Cretaceous–earliest Palaeocene time). Much, or all, of the westward breaching of the Salinia batholithic rocks likely occurred above the extrusion channels of the Rand-SdS schists; following this event, the Franciscan Sur-Obispo terrane was thrust beneath the schists, perhaps during the final stages of extrusion in the upper channel. Later, the Sur-Obispo terrane was partially extruded from beneath the Salinia nappe terrane, during which time the upper plate(s) underwent extension and subsidence to marine conditions. Attenuation of the Salinia nappe sequence during the extrusion of the Franciscan Complex thinned the upper crust, making the upper plates susceptible to erosion from the top of the Franciscan Complex near San Simeon, where it is now exposed. In the San Emigdio Mountains, the relatively thin structural thickness of the upper batholithic plates made them susceptible to late Cenozoic flexural folding and disruption by high-angle dip–slip faults. The ～100 km (～62 mi) of westward and northwestward breaching of the Salinia batholithic rocks above the Rand-SdS channels, and the underlying Nacimiento fault followed by ～510 km (～320 mi) of dextral slip from ～23 Ma to Holocene time along the SAF system, allow for the palinspastic restoration of Salinia with the crystalline rocks of the San Emigdio–Tehachapi mountains and the Mojave terrane, resolving the enigma of Salinia.     

Late Quaternary Tectonic Deformation of the Eastern End of the Altyn Tagh Fault

The Quaternary activity of the faults at the eastern end of the Altyn Tagh fault, including the Dengdengshan–Chijiaciwo, Kuantanshan and Heishan faults, was studied on the basis of interpretation of satellite images, trenching, geomorphologic offset measurements and dating. The Altyn Tagh fault has extended eastwards to Kuantanshan Mountain. The left–slip rates of the Altyn Tagh fault decreased through the Qilianshan fault and were transformed into thrust and folds deformation of many NW–trending faults within the Jiuxi basin. Meanwhile, under NE–directed compression of the Tibetan plateau, thrust dominated the Dengdengshan–Chijiaciwo fault northeast of the Kuantanshan uplift with a rate lower than that of every fault in the Jiuxi basin south of the uplift, implying that tectonic deformation is mainly confined to the plateau interior and the Hexi Corridor area. From continual northeastward enlargement of the Altyn Tagh fault, the Kuantanshan uplift became a triangular wedge intruding to the east, while the Kuantanshan area at the end of this wedge rose up strongly. In future, the Altyn Tagh fault will continue to spread eastward along the Heishan and Jintananshan faults. The results have implications for understanding the propagation of crustal deformation and the mechanism of the India–Eurasian collision.     

同沉积断裂构造对沉积相展布的控制——以黄河口凹陷沙三中亚段沉积相研究为例

研究表明,黄河口凹陷沙河街组三段中亚段发育的沉积相类型有辫状河三角洲相、扇三角洲相、湖底扇相和湖泊相。同沉积断裂特征对沉积具有控制作用,陡坡带活动盆缘断裂控制扇三角洲的分布,缓坡带活动盆缘断裂控制辫状河三角洲分布;二级断裂对湖底扇和深水沉积区有明显的控制作用,东部断阶带中部发育的F20东西向同沉积断裂,控制了物源的主要注入通道——沟谷,对东部物源的注入具有长期影响。     

鲜水河断裂带色拉哈—康定段新发现的活动断层：木格措南断裂

鲜水河断裂带位于青藏高原东缘,是中国大陆内部地震活动性最强的大型活动断裂带之一。大量研究证据表明,鲜水河断裂带色拉哈—康定段未来几十年内发生破坏性强震的风险较高。目前正在规划建设的国家重大交通基础建设工程——川藏铁路,将在康定折多山地区直接穿越鲜水河活动断裂带。本研究通过高分辨率卫星影像的地质地貌解译和详细的野外构造地质填图,新发现一条发育于色拉哈断裂和折多塘断裂之间折多山花岗岩体内的长约24km的全新世活动断层,该断裂空间上可分成北、中、南三段,呈(正滑)左旋右阶雁行状排列,并将其命名为“木格措南断裂”。该活动断裂的发现对完善鲜水河断裂带色拉哈—康定段的精细几何图像和构造组合特征,准确评价鲜水河断裂带的地震危险性具有重要意义,并为川藏铁路施工建设和安全运营提供了重要科学数据支撑。     

华熊地块马超营断裂走滑特征及演化

对华熊地块南部的马超营断裂带的几何样式、组成特征及其变形特点等研究结果表明,马超营断裂带经历了韧性变形和脆性变形期。韧性变形分布于该断裂带的南侧,并发生了绿片岩相的动力变质作用,其中的S-C组构特征所指示的运动方向在其南北两侧,分别为向南和向北逆冲,呈现正花状特点,反映了该断裂带具有走滑逆冲性质的断裂。韧性变形主要发生于前印支期。燕山期,全面陆-陆碰撞期间其主要表现为脆性变形特征。脆性变形主要发育于其北侧,北东向的康山-七里坪断裂、红庄-陶村断裂是其次一级的派生断裂。通过对北东向断裂运动方向和前人的成果分析,以及这些构造的平面分布样式对比认为该断裂为一条左行走滑特征的断裂带。在此基础上,结合区域动力学背景,进而讨论了它的演化特征。     

Slip Rate of Yema River–Daxue Mountain Fault since the Late Pleistocene and Its Implications on the Deformation of the Northeastern Margin of the Tibetan Plateau

The slip rate of Yema River–Daxue Mountain fault in the western segment of Qilian Mountains was determined by the dated offset of river risers or gullies. Results indicate that the left-lateral fault slip rate is 2.82 ± 0.20 mm/a at Dazangdele site,2.00 ± 0.24 mm/a at Shibandun site,and 0.50 ± 0.36 and 2.80 ± 0.33 mm/a at two sites in Zhazihu. The ideal average slip rate of the whole fault is 2.81 ± 0.32 mm/a. The lower slip rate confirms part of the displacement of Altyn Tagh fault was transformed into an uplifting of the strap mountains in the western segment of Qilian Mountains,whereas another part transformed into sinistral displacement of Haiyuan fault. This study illustrates that the slip of large strike-slip faults in the northeastern margin of the plateau transforms into crust thickening at the tip of the fault without large-scale propagation to the outer parts of the plateau.     

岷山隆起边界断裂构造活动初步研究

岷山隆起西以岷江断裂为界,东为虎牙断裂。该地区构造活动强烈,地震活动频繁,是重要活动区。岷山隆起是岷江断裂和虎牙断裂由西向东的推覆逆掩运动差异运动导致的。GPS及地质研究表明岷江断裂、虎牙断裂现今仍在活动。岷江断裂为左右旋走滑断裂,运动速度大于2mm／a;虎牙断裂整体速度2．55mm／a,断裂性质为右旋走滑断裂,而震源机制解为左旋走滑断裂。这一结果,可能与GPS观测时段、位置及断裂面结构、几何特征有关。     

Multistage deformation of linked fault systems in extensional regions: An example from the northern Perth Basin,Western Australia

Linked fault systems identified in the northern portion of the onshore Perth basin comprise north‐striking normal faults, the dominant structures in the basin, and hard linkages—east‐striking transfer faults. The former are either divided into segments of distinctive character by, or terminate at, the transfer faults. The fault systems were initiated by west‐southwest‐east‐northeast extension in the Early Permian but were reactivated by subsequent rifting with approximately east‐west extension in the Jurassic. They were also reactivated by the oblique extension of northwest‐southeast orientation associated with Gondwana continental breakup in the Late Jurassic ‐ earliest Cretaceous. In addition to reactivation, older structures of the linked fault families controlled the development of younger fractures and folds. During the oblique extension, the linked fault systems define releasing bends, characterised by a rollover anticline in the hangingwall of the Mountain Bridge Fault, and restraining bends where contractional folds are sites of major commercial hydrocarbon fields in the basin.     

帕米尔东北缘-西昆仑的构造地貌及其构造意义

帕米尔东北缘-西昆仑位于青藏高原西北部,受三条大型断裂:康西瓦断裂、主帕米尔-铁克里克断裂和公格尔断裂的制约.通过野外考察、卫星遥感图像解译、ASTER GDEM高程数据的分析,对上述三条断裂及整个区域进行构造地貌研究,并探讨其构造意义.结果表明:康西瓦断裂为左行走滑断裂;主帕米尔-铁克里克断裂为逆冲断裂;公格尔断裂和塔什库尔干断裂分别为右行、左行走滑正断层,连接两者的是塔合曼正断裂.通过ASTER GDEM高程数据的高程分布、局部高程差和坡度分析,表明帕米尔东北缘-西昆仑至塔里木盆地存在三级特征地貌(塔里木盆地、塔里木盆地南缘山前褶皱逆冲带和帕米尔东北缘-西昆仑);西昆仑地区受印度/亚洲板块碰撞而产生垂向物质运动,由于三条大型断裂控制在西侧断裂附近存在水平方向的物质运动,垂直和水平两种运动的存在促使靠近康西瓦和公格尔断裂形成高山地貌.     

中卫断裂带断层类型划分及其构造意义

中卫断裂带在晚更新世以来的左旋走滑运动中,先存的挤压逆掩、逆冲断裂带发生了分化。某些断层或断层段继续活动;另一些先存断层在晚更新世以来不再活动;此外,还发育了一些新断层。因此,我们把中卫断裂带划分出三种断层类型,即新生断层、继承性断层和遗弃断层。新生断层就是指：在某次构造运动中新发育的断层。具体到中卫断裂带来说,就是指晚更新世以来新发育的断层。这类断层是中卫断裂带左旋走滑运动的产物。在早期的挤压逆断运动中这些断层并不存在。通过对新生断层的调查研究可以获得以下资料。①反演晚更新世以来的构造应力场;②确定晚期构造运动的起始时代;③估算断层的断错幅度和速率。继承性断层就是指：在早期的挤压逆掩（冲）活动中就已经存在的断层或断层段,在晚期的左旋走滑运动中继续活动。继承性断层的最大优点是包含了较多的信息量。①继承性断层记录了多期构造运动的信息;②继承性断层是中卫断裂带多期活动的见证;③继承性断层是研究构造演化过程的重要依据。遗弃断层就是指：某些断层或断层段在早期构造运动中是主体断裂带的一部分,其活动习性与主体断裂带基本一致。当早期的构造运动终止之后,这些断层或断层段在后继的构造运动中不再活动,也就是说这些断层被遗弃。遗弃断层的作用就在于它保留了早期构造运动的大部或全部信息,这些信息基本上没有受到后期构造运动的干扰破坏。因而通过对遗弃断层的研究可以获得早期构造运动的主要信息。①确定早期构造运动终止的年代;②反演早期构造应力场方向;③研究断层的滑动方式,即粘滑和蠕滑。     

龙泉山断裂带隐伏断层氡气特征及其活动性分析

龙泉山断裂构造带作为龙门山推覆带的前陆隆起,严格控制了成都平原东边界,其活动性历来受到人们的关注。通过对龙泉山断裂带的氡气进行测量,可以有效地判断隐伏断层的位置及其活动性。测量结果显示,龙泉山断裂带北段东坡活动性强于西坡,主断层的活动性明显强于边缘隐伏断层,4条断层的活动性由强到弱依次为合兴场断层红花塘断层龙泉驿断层松林场断层。龙泉山断裂带同一条断层在地表由多个破碎带组成,其氡气异常特征与断层活动性和破碎带特征呈正相关性,即断层活动性越强,氡气异常特征越显著。龙泉山断裂带氡气平均异常浓度是背景值的9.6倍,将各异常带峰值浓度与背景值进行对比分析,大致归纳出了龙泉山地区隐伏断层活动性的相对判别标准。     

梨树断陷控陷断层的动态活动特征

桑树台断层是梨树断陷唯一一条控制断陷结构的一级断层,其动态活动特征、位移量以及对梨树断陷的控制作用等问题制约着层序地层格架和沉积体系的建立。根据该断层的生长模式,用位移—长度关系法分析其在火石岭、沙河子、营城、登娄库等地在坳陷期位移量的变化特征,定量计算不同时期断层最大位移量,分析了桑树台断层的复合式动态生长模式后认为,桑树台断层早期分南、中、北三段独立活动,控制了桑树台主洼、苏家屯次洼、金山次洼的沉积,到沙河子组后期拼合成一条断层。     

沧东断裂山岭子东段地质构造分析

依据钻井、MT测深、地震剖面资料对沧东断裂山岭子东段地质构造进行了研究,认为该段沧东断裂断面形态呈“阶形”,自沧县隆起至北塘凹陷由高、中、低三个台阶组成断阶构造。中生代白垩纪末期,在南东-北西向压扭应力作用下形成褶皱及逆断层,新生代古近纪反转为正断层,断阶带内发育北东及北北西向共轭剪切断层,它们是沟通不同热储层的重要通道。     

辽东湾坳陷东部地区新生代断裂体系与构造演化

断裂体系发育特征是辽东湾坳陷东部地区新生代构造演化的重要表现形式,运用丰富的三维地震资料,详细刻画了 研究区断裂体系平面和剖面特征。断裂体系特征分析表明: 研究区古新世-渐新世的断裂体系主要由NNE向的拉张正断层组 成;渐新世时期的断裂体系则表现出走滑断裂的性质,主干断裂附近出现走滑效应产生的增压区和释压区,同时发育似花 状构造和多级“y”字型构造,次级断裂多表现为雁列状的NEE向断裂;新近纪时期断裂体系仍以雁列状断裂为主,发育 共轭状剪切破裂以及“背形负花”状构造。断裂体系的研究明确了研究区新生代走滑构造系统与伸展构造系统的叠加改造 过程,结合研究区构造动力学背景,将辽东湾坳陷东部地区的构造演化阶段划分为古新世-始新世的弱走滑强拉张期、渐 新世的弱拉张强走滑期以及新近纪的弱挤压弱走滑期。     

三峡库首区仙女山等断裂活动性同位素测年研究

在仙女山、九湾溪两断层形变监测洞室中,通过对断裂带进行地质编录和对构造岩进行微观分析,挑选出断层泥与方解石两类样品进行热释光(TL)测年。同时对洞外披覆跨仙女山断层上的第四纪河流冲积物、断层一侧周坪河谷底上第四纪湖相纹泥夹碳化木及披覆跨九湾溪断层上的第四纪崩滑堆积体中滑带土进行测年。综合分析表明,仙女山断层与九湾溪断层新活动年龄与三峡地区区域断层基本一致,为距今22～23万年左右。最新活动年龄仙女山断层为16～19万年、九湾溪断层为14万年左右。最新活动年龄的下限值仙女山断层为14～16万年、九湾溪断层为13万年左右。晚更新世以来,两断层均没有活动迹象。九湾溪断层上的滑坡为外动力作用所致,并非该断层活动作用的结果。