Structural evolution of the Teletsk graben (Russian Altai)

Lake Teletskoye in the northeastern part of the Altai mountain range has attracted the attention of geo-scientists for a long time, because it fills an impressive tectonic depression. The lake is 77 km long and 4 km wide, and it has a maximum water depth of 325 m. The vertical offset of the basement surface is up to 3000 m. A multidisciplinary study of the Teletsk graben was carried out during the last few years, including satellite image and air photo analysis, bathymetric-, structural- and geomorphological mapping, high-resolution seismic profiling and seismic refraction. The structural study revealed that reactivation of preexisting weak basement zones is important in controlling the basin formation. These zones separate different tectonic terranes at the contact of which the Teletsk graben developed.This study identifies the significance of the basin in the regional neotectonic context. It shows that the major vertical movements are restricted to the basin itself, but do not characterize the whole region. Outside of the basin, recent tectonic structures have the same pattern as adjacent areas of Northeast Altai and West-Sayan. Quaternary glaciations have had no major influence on the basin formation.Two stages of faulting are identified. First, transpressive movements restricted to discrete (reactivated) fault zones controlled the opening of the basin. In the second stage, normal faulting is dominant and is responsible for the modern basin outline.An echo-sounding survey led to the recognition of several morphological characteristics of the lake bottom. In the southern part, the uppermost sediments seem slightly disturbed, whereas further north, transverse ridges and slope breaks are increasingly common. The deepest part of the lake is located in a highly disturbed zone of normal fault-bounded blocks. The structural difference between the southern and northern subbasins is supported by the interpretation of a deep seismic refraction profile which indicates a substantial increase of basement isochores in the area where the reactivated Teletsk (Paleozoic) shear zone crosses the lake.Correlation of high-resolution seismic profiles suggests that the Teletsk graben started to evolve during the Pleistocene, and that its present shape was formed in two stages. The first stage was responsible for the opening of the southern basin. It probably started in the Middle Pleistocene. A second kinematic stage induced by a sinistral reactivation of the NE striking West-Sayan fault initiated the opening of the different segments of the northern subbasin due to opposite movements between the reactivated Teletsk and West-Sayan faults. This second stage was active after the end of Late Pleistocene glaciations and during the Holocene. The recent lateral extension and the related N–S-trending normal faults result from a change in tectonic regime, with related extensional movements along the main reactivated fault zones. These recent movements result in the lateral escape of the lake borders and the collapse of the area between them.     

Paleoearthquakes in the Uimon basin (Gorny Altai)

Paleoseismological studies confirm that the Uimon basin is thrust by its northern mountain border along the active South Terekta fault. The latest motion along the fault in the 7-8th centuries AD induced an earthquake with a magnitude of M_w= 7.4-7.7 and a shaking intensity of I = 9-11 on the MSK-64 scale. The same fault generated another event (M > 7, I = 9-10), possibly, about 16 kyr ago, which triggered gravity sliding. The rockslide dammed the Uimon valley and produced a lake, where lacustrine deposition began about 14 ± 1 kyr ago, and a later M > 7 (I = 9-10) earthquake at ~ 6 ka caused the dam collapse and the lake drainage. Traces of much older earthquakes that occurred within the Uimon basin are detectable from secondary deformation structures (seismites) in soft sediments deposited during the drainage of a Late Pleistocene ice-dammed lake between 100 and 90 ka and in ~ 77 ka alluvium. The magnitude and intensity of these paleoearthquakes were at least M > 5.0-5.5 and I > 6-7.     

A Vendian-Cambrian Island Arc System of the Siberian Continent in Gorny Altai (Russia, Central Asia)

An extended Vendian-Cambrian island-arc system similar to the Izu-Bonin-Mariana type is described in the Gorny Altai terrane at the margin of the Siberian continent.

Three different tectonic stages in the terrane are recognized. (1) A set of ensimatic active margins including subducted oceanic crust of the Paleo-Asian ocean, the Uimen-Lebed primitive island arc, oceanic islands and seamounts: the set of rocks is assumed to be formed in the Vendian. (2) A more evolved island arc comprising calc-alkaline volcanics and granites: a fore-arc trough in Middle-late Cambrian time was filled with disrupted products of pre-Middle Cambrian accretionary wedges and island arcs. (3) Collision of the more evolved island arc with the Siberian continent: folding, metamorphism and intrusion of granites occurred in late Cambrian-early Ordovician time.

In the late Paleozoic, the above-mentioned Caledonian accretion-collision structure of the Siberian continent was broken by large-scale strike-slip faults into several segments. This resulted in the formation of a typical mosaic-block structure.     

Unknown large ancient earthquakes along the Kurai fault zone (Gorny Altai): new results of palaeoseismological and archaeoseismological studies

Palaeoseismological and archaeoseismological studies in the Kurai fault zone, along which the Kurai Range is thrust onto Cenozoic deposits of the Chuya intramontane basin, led to the identification of a long reverse fault scarp 8.0 m high. The scarp segments are primary seismic deformations of large ancient earthquakes. The scarp’s morphology, results of trenching investigations, and deformations of Neogene deposits indicate a thrusting of the piedmont plain onto the Kurai Range, which is unique for the Gorny Altai. Similarly for Northern Tien Shan, we explain this by the formation of both a thrust transporting the mountain range onto the depression and a branching thrust dislocation that forms the detected fault scarp. In a trench made in one of the scarp segments, we identified the parameters of the seismogenic fault – a thrust with a 30° dipping plane. The reconstructed displacement along the fault plane is 4.8 m and the vertical displacement is 2.4 m, which indicates a 7.2–7.6 magnitude of the ancient earthquake. The ¹⁴C age of the humus-rich loamy sand from the lower part of the colluvial wedge constrains the age of the earthquake at 3403–3059 years BP. Younger than 2500 years seismogenic displacements along the fault scarp are indicated by deformations of cairn structures of the Turalu–Dzhyurt-III burial mound, which was previously dated as iron age between the second half of I BC and I AD.     

Zonal Metamorphic Complex in the Tongulack Mountain Ridge, Altai, Russia, and Explanation of Its Origin with the Help of Thermal Modelling

A moderate pressure / high temperature zonal metamorphic complex in the Tongulack Mountain Ridge, Altai, Russia, is described, and the applicability of the models of magmatic intrusion and fluid flow to explanation of its origin discussed. The Precambrian complex was formed at 500-700℃ and 3.0-5.5 kbars; it is a linear, 25-30 km wide, thermal anticline with a curved axis showing symmetric metamorphic zoning. The metamorphism was isochemical by its nature, as is corroborated by the chemical compositions of the rocks. Four zones can be recognized within the metamorphic complex: chloritic (on the peripheries), cordieritic, sillimanitic and staurolite-out (in the centre). The zones are separated by successive isograds: cordierite, staurolite-in or sillimanite and staurolite-out. It is argued that the origin of the metamorphic zoning can be explained best by a combined fluid-magmatic model; conductive heat flow from the intrusion predominated considerably over the fluid flux in heat transfer: the fluid flow     

阿尔泰冲乎尔盆地花岗质岩类的锆石SHRIMP U-Pb定年及其构造意义

通过对新疆阿尔泰冲乎尔地区北缘花岗质类岩石的矿物学、岩石学及电子探针分析研究,鉴定冲乎尔盆地北缘花岗岩属斜长花岗岩．英云闪长岩系列。岩石主微量元素分析显示,花岗岩和盆地火山沉积岩具有相似的微量及稀土元素特征,表现为：准铝到弱铝过饱和的钙碱性系列,镁含量较高,Ba、Y、Nb等大离子亲石元素亏损,轻稀土富集,稀土元素分布曲线为Eu弱负异常的右倾平坦型,岩石地球化学特征显示花岗岩的物质来源可能主要来自中上地壳。用单颗粒锆石SHRIMP U-Pb定年方法。测得该岩体成岩年龄为413±3.8Ma,晚于盆地火山岩436±4Ma,结合花岗岩分布及基底构造特征,认为该期花岗岩受区域南北向构造控制,冲乎尔盆地可能为早古生代火山沉积盆地,盆地岩浆岩相似的元素地球化学特征暗示它们可能具有同源岩浆演化系列的性质。该期花岗岩可能为志留纪活动大陆边缘环境下,古亚洲洋板块向西伯利亚板块俯冲,热一构造作用引起中上地壳部分熔融,在阿尔泰山及其南缘形成S型花岗岩。     

Segmentation and inversion of the Hangjinqi fault zone,the northern Ordos basin (North China)

This paper deals with the segmentation and inversion of the Hangjinqi fault zone (HFZ), which is the dominant structure in the northern part of the Ordos basin in North China. HFZ was reactivated during the Late Triassic and obliquely inverted during the Middle Jurassic shortening. Subsurface geological mapping and structural analysis were carried out to determine the segmentation and kinematic history of the deformation. The HFZ was a left-stepping fault zone and was made up of three segments: the Porjianghaizi fault (PF), Wulanjilinmiao fault (WF) and Sanyanjing fault (SF), which are separated by two relay ramps. Two distinct phases can be identified in its structural evolution: (1) during the Late Triassic compressional deformation, the HFZ was characterized by shortening and thrusting to the north; and (2) During the Middle Jurassic phase the HFZ was oblique to the extensional fault trends, the reverse faults were reactivated as dextral strike-slip faults as a result of transtensional inversion. The inversion ratio of the HFZ indicates an increase in deformational degree from east to west over the whole region. The first deformation stage resulted from the N–S compression between the South China and North China plates during the Late Triassic. The second deformation stage of compression was related to the west-northwestward subduction of the paleo-Pacific plate during the Middle Jurassic. In the Jurassic deformation framework, the HFZ may be interpreted as an accommodation structure parallel to the Yanshan–Yinshan orogenic belt developed in the northern Ordos area.     

新疆阿尔泰山南缘蒙库盆地火山沉积构造演化与成矿

阐述了蒙库早泥盆世火山沉积盆地的构造特征。通过对该盆地火山沉积构造演化及其与成矿关系的研究，其结果认为，该盆地是一个明显的非对称的陆内裂谷，其火山沉积构造演化过程可划分为二个阶段：早期石英角斑质火山沉积阶段和晚期细碧-角斑质火山沉积阶段。由于蒙库铁矿床的喷流沉积成矿作用主要发生在第二个火山沉积构造演化阶段．因此铁矿床集中产于向斜构造的核部地层．并与细碧-角斑岩建造关系密切。后期的变质变形-岩浆侵入作用又对海底喷流沉积矿床起到了明显的改造-叠加富集成矿作用。     

Geometry of the fault zone of the 2003 Ms = 7.5 Chuya earthquake and associated stress fields, Gorny Altai

The co-seismic deformations produced during the September 27, 2003 Chuya earthquake (Ms = 7.5) that affected the Gorny Altai, Russia, are described and discussed along a 30 km long segment. The co-seismic deformations have manifested themselves both in unconsolidated sediments as R- and R′-shears, extension fractures and contraction structures, and in bedrock as the reactivation of preexisting schistosity zones and individual fractures, as well as development of new ruptures and coarse crushing zones. It has been established that the pattern of earthquake ruptures represents a typical fault zone trending NW–SE with a width reaching 4–5 km and a dextral strike–slip kinematics. The initial stress field that produced the whole structural pattern of co-seismic deformations during the Chuya earthquake, is associated with a transcurrent regime with a NNW–SSE, almost N–S, trending of compressional stress axis (σ₁), and a ENE–WSW, almost E–W, trending of tensional stress axis (σ₃). The state of stress in the newly-formed fault zone is relatively uniform. The local stress variations are expressed in insignificant deviation of σ₁ from N–S to NW–SE or NE–SW, in short-term fluctuations of relative stress values in keeping their spatial orientations, or in a local increase of the plunge angle of the σ₁. The geometry of the fault zone associated with the Chuya earthquake has been compared with the mechanical model of fracturing in large continental fault zones with dextral strike–slip kinematics. It is apparent that the observed fracture pattern corresponds to the late disjunctive stage of faulting when the master fault is not fully developed but its segments are already clearly defined. It has been shown that fracturing in widely different rocks follows the common laws of the deformation of solid bodies, even close to the Earth surface, and with high rates of movements.     

攀西裂谷内陆盆地自由热对流应力分析及盆地沉降

康滇地区裂谷作用已得到证实,但形成这种地堑地垒的格局有多种解释,以传统的地质力学分析为主。笔者借以热力学的自由热对流原理来加以论述:攀西巨厚的火山岩体在下覆异常地幔热作用下,发生自由热对流,引起热量散失,使地壳沉降与隆起不均衡,生成地堑地垒的格局。自由对流单元的侧向迁移,使盆地形成非对称性。     

下扬子区新生代断陷盆地的构造与形成

为了揭示下扬子海陆全区新生代断陷盆地的构造特征,进而探讨盆地的形成机理,故对研究区的地震、钻井和地质资料进行系统分析,梳理区内的主要构造地质证据,并在时空上进行对比。垂直盆地走向的区域大剖面构造解析显示,下扬子区由陆至海,盆地范围逐步扩大,断陷充填厚度逐渐增厚,结构趋于复杂,表明盆地的拉伸量和伸展强度自西向东呈增大趋势。受下扬子块体近似楔形几何形状与东部侧向挤压的边界条件约束,块体近南北向侧向扩展,块体内区域伸展,前新生代的基底先存断裂复活,诱发区域张裂作用和盆地沉降,断陷盆地形成受基底应力两个基本因素制约。下扬子新生代块体的伸展与郯庐断裂的右旋走滑,均为下扬子块体构造形变的地质响应,其动力学机制可用太平洋板块北西向俯冲进行解释。     

阿尔金断裂带新生代活动在柴达木盆地中的响应

阿尔金断裂新生代以来发生多期次的走滑运动,并伴随强烈的隆升作用,进而影响柴达木盆地新生代的构造演化。本文通过遥感卫星影像解译、地震反射剖面解释、区域地层分析,结合野外考察资料对阿尔金断裂新生代活动在柴达木盆地中的响应进行了研究。对柴达木盆地卫星影像的解译发现盆地中褶皱形态指示了近东西走向的褶皱构造带与近南北走向的褶皱构造带的叠加干涉效应,其中近东西向褶皱构造带是在印度/欧亚板块碰撞作用下青藏高原隆升并向北东扩展过程的响应,近南北向褶皱构造带是阿尔金断裂新生代活动的响应。对NW-SE向穿过阿尔金山-柴达木盆地的盆山结合带地震反射剖面的再解释,发现新生代地层中发育的多层生长地层,记录了阿尔金断裂新生代活动的信息。对盆地中新生代地层分布等厚图褶皱干涉样式的分析表明,上油砂山组沉积时期(14.9Ma)阿尔金断裂活动已经明显影响到柴达木盆地,而狮子沟组沉积时期(8.2~2.6Ma)断裂活动对柴达木盆地改造最强。通过对研究区已有的低温热年代学数据和沉积、构造、磁性地层年代学等方面研究成果的总结和分析,认为阿尔金断裂在新生代至少存在三期(~30Ma,~8Ma、~2.6Ma)强烈的构造活动和隆升作用,在柴达木盆地内表现为相应地质时代沉积速率的加快、沉积物岩性的变化、构造地貌的变形和同构造生长地层的出现。其中后两期(~8Ma、~2.6Ma)构造活动在整个青藏高原及周边地区广泛存在,为准同期构造事件,而月牙山地区地震地表破裂带的发现则表明阿尔金断裂带现在仍在强烈活动,并且直接影响到了柴达木盆地。阿尔金断裂带新生代以来的构造活动具有多期性,并影响和改造了柴达木盆地,可能对油气成藏有重要影响。     

Dynamics of the formation of the Cenozoic Uglovsky basin (Southern Primorye)

The Uglovsky basin located in the southern part of Primorye is filled in with Eocene terrigenous predominantly nonmarine coal-bearing deposits. The basin is considered to be the result of syn-strike-slip extension, which occurred prior to the opening of the Sea of Japan and was related to dextral displacements along NNE-trending faults.     

Chemical brecciation processes in the Sue unconformity-type uranium deposits, Eastern Athabasca Basin (Canada)

Chemical brecciation in sandstone is common in many unconformity-type uranium deposits of the Athabasca Basin, and is expressed in some of them as ball zone breccia. Ball zones are composed of rounded argillized sandstone fragments, varying in size from several centimeters to 1 m, wrapped in a clay matrix. The Sue C open pit provided a unique opportunity to map and to study such ball zones. Here, they were up to 5 m wide with a 20–30 m vertical extension. They were mainly observed along a reverse fault controlling the Sue A and B uranium deposits, and were well developed at intersections with dextral NE-trending structures. Their maturity, characterized by the matrix percentage, increased toward the unconformity and at fault intersections. They are characterized by massive quartz dissolution, hematite leaching, (Ca,Sr,LREE)Al-phosphates crystallization and replacement of dickite by illite. Illite composition indicates formation temperatures of 240–280 °C, close to peak diagenesis conditions in the basin. Mass balance calculations show that V, K, Rb, B, LREE, Mg, Cr, Sr, U and Y were added and Si and Fe leached out with up to 85% volume loss.Ball zones were initiated by tectonic fracturing in sandstone during reverse faulting. Consecutive permeability increase induced basement fluid circulation in the sandstone with quartz dissolution along fractures. With a silica saturation of the fluid of 90%, a minimum fluid/rock ratio of 38,000 is obtained. The rounded morphologies of the breccia fragments are attributed to a diffusion-limited regime of dissolution. The resulting increase of clay content led to self-sealing of the hydrothermal system. Seismic reactivation may have been periodically rejuvenated the permeability. These processes seem to be coeval with the formation of structurally controlled high-grade unconformity-type uranium mineralization. Formation of the ball zones required probably more than 1 million years.     

Transpressional deformation,strain partitioning and fold superimposition in the southern Chinese Altai,Central Asian Orogenic Belt

Transpressional deformation has played an important role in the late Paleozoic evolution of the western Central Asian Orogenic Belt (CAOB), and understanding the structural evolution of such transpressional zones is crucial for tectonic reconstructions. Here we focus on the transpressional Irtysh Shear Zone with an aim at understanding amalgamation processes between the Chinese Altai and the West/East Junggar. We mapped macroscopic fold structures in the southern Chinese Altai and analyzed their relationships with the development of the adjacent Irtysh Shear Zone. Structural observations from these macroscopic folds show evidence for four generations of folding and associated fabrics. The earlier fabric (S₁), is locally recognized in low strain areas, and is commonly isoclinally folded by F₂ folds that have an axial plane orientation parallel to the dominant fabric (S₂). S₂ is associated with a shallowly plunging stretching lineation (L₂), and defines ∼NW-SE tight-close upright macroscopic folds (F₃) with the doubly plunging geometry. F₃ folds are superimposed by ∼NNW-SSE gentle F₄ folds. The F₃ and F₄ folds are kinematically compatible with sinistral transpressional deformation along the Irtysh Shear Zone and may represent strain partitioning during deformation. The sub-parallelism of F₃ fold axis with the Irtysh Shear Zone may have resulted from strain partitioning associated with simple shear deformation along narrow mylonite zones and pure shear-dominant deformation (F₃) in fold zones. The strain partitioning may have become less efficient in the later stage of transpressional deformation, so that a fraction of transcurrent components was partitioned into F₄ folds.     

苏北盆地构造演化研究进展

苏北盆地位于苏鲁造山带南侧、下扬子地台的东北部,盆地所处的特殊构造位置使其演化历史颇为复杂。总结了近年来苏北盆地构造演化研究方面的进展,如盆地基底、深部构造、形成机制、盆地与下扬子区构造演化之间的关系等研究的进展。对近年来获得的新认识进行分析和归纳,提出了今后苏北盆地构造演化研究中一些值得关注的问题,如盆地基底构造与浅部构造之间的关系、苏鲁造山带与盆地构造演化的联系、郯庐断裂对盆地形成的影响、盆地形成的动力学机制等。     

苏北盆地构造演化研究进展

苏北盆地位于苏鲁造山带南侧、下扬子地台的东北部,盆地所处的特殊构造位置使其演化历史颇为复杂。总结了近年来苏北盆地构造演化研究方面的进展,如盆地基底、深部构造、形成机制、盆地与下扬子区构造演化之间的关系等研究的进展。对近年来获得的新认识进行分析和归纳,提出了今后苏北盆地构造演化研究中一些值得关注的问题,如盆地基底构造与浅部构造之间的关系、苏鲁造山带与盆地构造演化的联系、郯庐断裂对盆地形成的影响、盆地形成的动力学机制等。     

塔里木盆地西南缘山前带逆冲推覆构造特征

塔里木盆地西南缘山前带是西昆仑逆冲推覆构造在前陆形成的冲断带,主要由断层相关褶皱、双重构造、叠瓦状构造、三角带等构造组成。通过地表构造剖面、地震与非震资料的综合解释与研究,结合平衡剖面的正演方法,对该冲断带进行了几何学、运动学与动力学研究,对冲断带断层的扩展方式以及冲断时代进行了讨论。研究认为塔西南逆冲推覆构造具有"南北分带、东西分段以及垂向结构变异"的特点。自南向北分为逆冲推覆的根带、中带、锋带和反冲断裂带,由西向东可以划分为帕米尔弧形构造段、齐姆根弧形构造段、甫沙-克里阳三角带构造段与和田南逆冲推覆体构造段。冲断带在垂向结构上由三套区域性滑脱层划分为浅构造层次的外来系统断坡背斜、中构造层次的准原地系统双重构造、三角带构造以及深构造层次的原地系统弱变形带三层结构。冲断席内断层的扩展方式为前展式,而不同冲断席间则为后展式模式。冲断带自中新世中期开始形成,中新世末发生位移推覆,上新世—早更新世定型,中更新世—全新世隆升均衡调整。     

西秦岭北缘构造带新生代盆地南部边界断层带结构与构造变形演化

西秦岭北缘构造带是青藏高原东北缘的主要构造边界之一,北缘断层及其所控制的新生代沉积盆地是青藏高原东北缘新生代盆—山格局演化、高原扩展隆升与变形的地质记录。因此,西秦岭北缘构造带的断裂构造和断裂控制的沉积盆地研究对于理解青藏高原构造系统形成和高原隆升过程都具有重要的科学意义。本文通过对西秦岭北缘新生代盆地的南部边界断层F1断层结构分带、断层岩类型、几何学—运动学特征分析,获得如下认识：1）F1断层总体走向为290°～300°,倾向北北东,倾角60°～80°,发育近百米宽的由韧性、韧脆性和脆性断层岩等组成的结构复杂的断层带;2）构造分析揭示了F1断层至少经历了 3期构造变形事件,第一期为韧性—韧脆性伸展正断层作用,第二期为脆性高角度挤压逆冲断层作用,第三期为近直立的脆性斜向左旋走滑作用;3）该断层近百米宽的断层带内形成于不同构造层次的韧性、韧脆性、脆性等变形现象叠加交织出现在现今地壳浅表层次,说明该断层带经历了从早期较深层次韧性变形域逐渐抬升而进入晚期较浅层次的脆韧性变形域到现今的脆性变形域的韧—脆性变形机制转换;4）根据F1断层对西秦岭北缘渐新统—中新统漳县含盐红层盆地的空间构造配置、控制和改造以及新生代区域构造变形演化历史分析,认为第一期韧性—韧脆性伸展正断层作用与渐新世—中新世断陷盆地形成相匹配,活动时代为晚渐新世—晚中新世;第二期脆性高角度挤压逆冲作用与渐新世—中新世地层翘起、褶皱和底部抬升剥蚀及上新世磨拉石盆地充填相对应,活动时代应该始于中新世末期或上新世早期,持续至第四纪早期;第三期斜向左旋走滑则与西秦岭北缘断层带第四纪以来广泛发育的左旋走滑作用相对应。综上所述,西秦岭北缘新生代漳县盆地南部边界断层F1,虽然仅是北缘构造带中一条断层,但作为构造敏感带,其多期变形历史应该代表了青藏高原东北缘新生代以来的构造变形演化及构造体制转换过程。如果这一新生代沉积盆地边界断层F1在渐新世—中新世一直处于伸展正断作用,那么西秦岭北缘在这个阶段应该处于地壳伸展拉张状态,渐新世—中新世漳县盆地只能是伸展断陷盆地而不可能是挤压挠曲前陆盆地或压陷盆地。因此,我们认为印度—欧亚板块碰撞汇聚产生的构造挤压缩短和地壳隆升效应在中新世尚未波及到西秦岭北缘区域。F1断层在中新世末—上新世初的构造反转挤压冲断和上新世具有再生前陆磨拉石堆积出现才标志着西秦岭北缘卷入青藏高原挤压构造动力学系统。     

琼东南盆地新生代发育机制的模拟研究

琼东南盆地是南海西北陆缘上一个北东走向的伸展裂陷带,向西与北西走向的莺歌海盆地相接,因此其构造演化包含了较多红河断裂走滑活动的信息。综合地质分析与物理模拟实验,我们发现琼东南盆地的发育既受控于南海北部陆缘的南东向—南南东向伸展作用,而且受到红河断裂左行走滑作用的控制和影响。其中,中央坳陷带主要受控于南东至南南东向的伸展作用;南部坳陷带的发育主要受控于琼东南盆地的伸展及其沿北北西向边界断裂右行走滑作用的构造叠加;而北部坳陷带的发育主要受控于北西向断裂左行走滑作用。红河断裂左行走滑作用可能开始于晚始新世,晚于琼东南盆地的伸展裂陷作用,且早期走滑速率应小于琼东南盆地的伸展速率,早渐新世(T70)以后红河断裂左行走滑速率大于琼东南盆地伸展速率,导致琼盆西段的褶皱反转,以及一组北西—北北西走向张剪断裂的发育。