The Relationship between Tectonic Subsidence and BSR of Upper Neogene in the Deep-Water Area of the Northern Continental Slope, South China Sea

BSR (Bottom Simulating Reflector) occurs widely in the strata since the late Miocene in the deep-water area of the northern continental slope of South China Sea (SCS). It is an important seismic reference mark which identifies the gas hydrate and its distribution influenced by the tectonic movements. Single-point basin modeling was conducted using 473 points in the study area. To discuss the relationships between the tectonic subsidence and BSR, the volume and rate of tectonic subsidence in each geological time have been simulated. The results show that there are three tectonic accelerate subsidence processes in the study area since the late Miocene, especially since 1.8Ma the tectonic subsidence accelerates more apparently. Since the Late Miocene to Pleistocene, the rate of tectonic subsidence in deep-water underwent a transformation from weak to strong. The ratio of tectonic subsidence to the total subsidence was relatively high (65-70%). Through the superposition of the BSR developed areas and the contours of tectonic subsidence in this area, it was discovered that more than 80% of BSR tend to be distributed at the slope break or depression-uplift structural transfer zone and the average tectonic subsidence rate ranges from 70 m/Ma to 125 m/Ma.     

Subsidence Analysis and Burial History of the Late Carboniferous to Early Jurassic Soutpansberg Basin, Limpopo Province, South Africa

The subsidence history of the Soutpansberg Basin was reconstructed by a tectonic subsidence analysis coupled with backstripping calculations based on data of newly interpreted sequence boundaries. Furthermore,burial and time plots were constructed in order to understand the burial and thermal history of the basin. Input data were based on facies,lithostratigraphic models and tectonic interpretations. The studied succession is up to 1000 m and is underlain by the Achaean Limpopo Mobile Belt. The subsidence within the basin supports the primary graben system which must have been centred within the present basins,and later became a region of faulting. The subsidence and burial history curves suggests two phases of rapid subsidence during the Early-Late Permian(300–230 Ma) and Middle Triassic(215–230 Ma). The areas of greater extension subsided more rapidly during these intervals. Two slow subsidence phases are observed during the Late Triassic(215–198 Ma) and Early Jurassic(198–100 Ma). These intervals represent the post-rift thermal subsidence and are interpreted as slow flexural subsidence. Based on these observations on the subsidence curves,it is possible to infer that the first stage of positive inflexion(300 Ma) is therefore recognised as the first stage of the Soutpansberg Basin formation.     

Cenozoic thermal history reconstruction of the Dongpu Sag,Bohai Bay Basin: Insights from apatite fission‐track thermochronology

Knowledge of the thermal history of the onshore Dongpu Sag (DPS), Bohai Bay Basin is important for understanding its tectonic development within a broader regional context and for elucidating its poorly studied source‐rock maturation history. To unravel DPS time‐temperature development, apatite fission‐track data were acquired from eight sandstone samples in three deep wells. Thermal history modelling indicates continuous heating during the rifting stage (early Eocene to late Oligocene), followed by cooling attributed to tectonic uplift between ~27 and ~16 Ma, which resulted in the removal of ~1,400 to 1,800 m of section. Reheating occurred during the subsidence stage from middle Miocene until present. Unlike typical passive continental margin basins, the DPS experienced accelerated post‐rifting subsidence from ~5.8 Ma, which was especially marked since ~2.6 Ma. This phase was probably triggered by normal fault reactivation, in combination with a variation in the deep heat flow pattern.     

Late Mesozoic rift evolution and crustal extension in the central Songliao Basin,northeastern China: constraints from cross-section restoration and implications for lithospheric thinning

The Songliao Basin, the largest oil-producing basin in China, was the centre of late Mesozoic rifting and lithospheric thinning in northeastern China. However, the rifts are still poorly revealed due to a thick cover of subsidence successions. By structural interpretation and sequential restoration of cross-sections based on new 2D seismic data and well data, this study presents the structural style, basin evolution, and horizontal crustal extension of the central Songliao Basin. We have developed a novel method to retrieve the regional extension principal strains. The results enable an assignment of rifting into two episodes. The earlier episode (ca. 157–130 Ma) was dominated by distributed faulting of numerous planar normal faults trending NNE–SSW, NNW–SSE, or near NS, probably reflecting pre-existing basement fabrics; in contrast, the later episode (ca. 130–102 Ma) was controlled by localized extension along several major listric faults. Horizontal crustal extension during rifting is estimated to have been 11–28 km (10.6%–25.5%), with the long-term average rate varying from 0.20 to 0.51 mm yr^–1. Regional horizontal strains show a gradual evolution from biaxial extension at the beginning of rifting to WNW–ESE uniaxial stretching during the later rifting episode. Brittle crustal extension is interpreted to have been associated with vertical strain due to tectonic stretching, which is estimated to have contributed more in thinning the lower crust than the mantle lithosphere. Accordingly, a two-episode dynamic model is proposed to explain rifting in the Songliao Basin. We suggest that the earlier event was dominated by delamination of the thickened continental lithosphere, whereas the later event was probably controlled by regional crustal detachment due to slab subduction and stagnancy of the Izanagi lithospheric plate.     

珠江口盆地深水区晚中新世以来构造沉降与似海底反射（BSR）分布的关系*

2007年中国在南海北部神狐海域通过钻探首次获得天然气水合物样品,证实了珠江口盆地深水区是水合物富集区。通过对珠江口盆地深水区构造沉降史的定量模拟研究,发现晚中新世以来区内构造沉降总体上具有由北向南、自西向东逐渐变快的演化趋势;从晚中新世到更新世,盆地深水区经历了构造沉降作用由弱到强的变化过程：晚中新世(11.6～5.3 Ma),平均构造沉降速率为67 m/Ma;上新世(5.3～1.8 Ma),平均构造沉降速率为68 m/Ma;至更新世(1.8～0 Ma),平均构造沉降速率为73 m/Ma。而造成这些变化的主因是发生在中中新世末-晚中新世末的东沙运动和发生在上新世-更新世早期的台湾运动。东沙运动（10～5 Ma）使盆地在升降过程中发生块断升降,隆起剥蚀,自东向西运动强度和构造变形逐渐减弱,使得盆地深水区持续稳定沉降;台湾运动（3 Ma）彻底改变了盆地深水区的构造格局,因重力均衡调整盆地深水区继续沉降,越往南沉降越大。将似海底反射（BSR）发育区与沉降速率平面图进行叠合分析,发现80％以上的BSR分布趋于构造沉降速率值主要在75～125 m/Ma之间、沉降速率变化迅速的隆坳接合带区域。     

黑龙江省三江盆地绥滨坳陷沉降史分析

三江盆地绥滨坳陷现有4口钻井的一维正、反演构造沉降模拟结果表明,绥滨坳陷显示出张裂盆地的特征,表现为120Ma之前张裂阶段和之后的裂后热沉降阶段。张裂阶段沉降速率大约为80.37m/Ma,沉降量达1300m,拉张因子大约为1.16。热沉降阶段的沉降速率降到了6.6m/Ma,沉降量也只有200m左右。     

南海礼乐滩碳酸盐台地的发育及其新生代构造响应

为了探索碳酸盐台地在海盆演化过程中的作用,对南海南部礼乐滩区域碳酸盐台地的发育及其与新生代构造沉降特征的相关性进行研究.对多道地震数据的分析表明:在研究区广泛发育包括碳酸盐台地和生物礁在内的碳酸盐沉积,其发育时间主要集中在晚渐新世至早中新世期间,在中中新世后开始退积和淹没.通过对穿越礼乐滩区的两条NW-SE向测线NH973-2和DPS93-2的构造沉降反演,进行沉降量、沉降速率计算和构造分析.结果表明:沉降速率及沉降量随不同时期的构造活动而发生变化,可分为缓慢沉降期(古新世-早渐新世,张裂阶段)、隆升剥蚀期(晚渐新世-早中新世,漂移阶段)、加速沉降期(早中新世末期,后漂移阶段1)、强烈沉降期(中新世,后漂移阶段2)和稳定沉降期(晚中新世至今,后漂移阶段3)5个发育期.碳酸盐台地的发育期和南海海盆的漂移阶段相对应,构造沉降的分析表明该期间具有构造抬升作用,其与相对上升的海平面结合有利于碳酸盐沉积的发育.在南海扩张期间主地幔对流的控制下,南部陆缘区礼乐地块和礼乐滩盆地之间较大的地壳厚度差异会导致侧向上地温梯度的差异,从而形成礼乐滩盆地之下的次生对流.该次生对流控制了研究区在晚渐新世至早中新世期间的隆升剥蚀作用.      

珠江口盆地构造演化旋回及其新生代沉积环境变迁

目前对珠江口盆地中生代以来的演化过程及其与沉积环境演变的响应关系尚缺乏系统性认识.基于珠江口盆地中-新生代岩浆活动、断陷结构样式及其改造、典型构造变形样式、沉积中心的转换等特征的对比分析,将盆地中-新生代的构造演化划分为4个阶段、7个期次:（1）中侏罗世-晚白垩世早期（~170~90 Ma）为古太平洋板块俯冲主控的陆缘岩浆弧-弧前盆地演化阶段;（2）晚白垩世-始新世中期（~90~43 Ma）为太平洋板块俯冲后撤背景下弧后周缘前陆/造山后塌陷-主动裂谷演化阶段;（3）始新世中期-中中新世（~43~10 Ma）为华南挤出-古南海俯冲拖曳主导的被动陆缘演化阶段;（4）晚中新世以来（~10~0 Ma）为菲律宾板块NWW向仰冲主导的挤压张扭演化阶段.~90 Ma、~43 Ma、~10 Ma分别实现了由安第斯型俯冲向西太平洋型俯冲、由主动裂谷向被动陆缘伸展、由被动陆缘伸展向挤压张扭的转换.在此过程中,伴随着古南海和南海的发育-消亡,新生代裂陷期沉积环境由东向西、由南向北逐渐海侵,裂后期由南向北阶段性差异沉降,由陆架浅水向陆坡深水转换,这使得珠一/三、珠二、珠四坳陷的石油地质条件具有显著的分带差异性.      

南海万安盆地构造—层序发育特征与构造—沉积充填演化

万安盆地是南海西南部重要的沉积盆地之一,深入分析其构造—沉积充填特征对于认识南海南部主要构造事件及其沉积响应具有重要的科学意义.利用覆盖全盆地的二维地震资料,结合国内外的研究成果,对万安盆地构造—层序特征及其构造—沉积充填演化进行分析.研究表明,万安盆地内新生代以来可识别出8个主要的二级/三级层序界面.沉降模拟显示,盆地沉降整体表现出一个“快—慢—快”的过程,且整体呈现出东高西低,中高南低的特征.综合构造层序特征和沉降模拟结果,万安盆地新生代以来沉积演化可分为5个阶段:初始裂陷期、晚期裂陷期、断坳转换期、裂后热沉降期和裂后加速热沉降期.盆地自形成以来,沉降主要受东亚大陆边缘区域拉张所造成的深部断裂的影响,至上新世,万安断裂转而成为盆地沉降的主要影响因素,并由此造成了早期盆地沉降中心由中部向西迁移,然后再逐步向东迁移的特征.渐新世至早中新世为盆地裂陷阶段,以陆源碎屑岩沉积为主,断陷早期可能为湖相,晚期为浅海相;中中新世为盆地断坳转换阶段,晚中新世以来为盆地裂后热沉降阶段,二者均发育陆源碎屑岩和自生碳酸盐岩两种沉积类型,且裂后热沉降期碳酸盐岩沉积范围相对缩小,陆缘碎屑岩沉积范围相对扩大.      

Thermochronological evidence for Mesozoic–Tertiary tectonic evolution in the eastern Sardinia

Apatite fission‐track analyses on samples from eastern Sardinia document a complex tectonic history, whose reconstruction is problematic because of the reactivation of faults and structures at different times from Jurassic to Miocene. The oldest ages (150–154 Ma) have been detected on the southern margin of the Gulf of Orosei and are related to the extensional tectonics that characterize the European passive margin during Early and Middle Jurassic times. Thermal modelling of these data allows reconstruction of the burial history of the Mesozoic basin and estimation of a sedimentary thickness of 2000 m. Part of these sediments was eroded during the following uplift, documented by mid‐Cretaceous fission‐track ages. A further exhumation episode of Eocene age has been revealed by fission‐track data on granite samples, and has been inferred to be related to the Alpine orogenic phase. This tectonic episode caused the exhumation of crustal blocks bound by faults that were finally reactivated during the Late Oligocene–Early Miocene.     

Chemical and Isotopic Characteristics of the Kuroko‐Forming Volcanism

The Miocene northeast Honshu magmatic arc, Japan, formed at a terrestrial continental margin via a stage of spreading in a back‐arc basin (23–17 Ma) followed by multiple stages of submarine rifting (19–13 Ma). The Kuroko deposits formed during this period, with most forming during the youngest rifting stage. The mode of magma eruption changed from submarine basalt lava flows during back‐arc basin spreading to submarine bimodal basalt lava flows and abundant rhyolitic effusive rocks during the rifting stage. The basalts produced during the stage of back‐arc basin spreading are geochemically similar to mid‐ocean ridge basalt, with a depleted Sr–Nd mantle source, whereas those produced during the rifting stage possess arc signatures with an enriched mantle source. The Nb/Zr ratios of the volcanic rocks show an increase over time, indicating a temporal increase in the fertility of the source. The Nb/Zr ratios are similar in basalts and rhyolites from a given rift zone, whereas the Nd isotopic compositions of the rhyolites are less radiogenic than those of the basalts. These data suggest that the rhyolites were derived from a basaltic magma via crystal fractionation and crustal assimilation. The rhyolites associated with the Kuroko deposits are aphyric and have higher concentrations of incompatible elements than do post‐Kuroko quartz‐phyric rhyolites. These observations suggest that the aphyric rhyolite magma was derived from a relatively deep magma chamber with strong fractional crystallization. Almost all of the Kuroko deposits formed in close temporal relation to the aphyric rhyolite indicating a genetic link between the Kuroko deposits and highly differentiated rhyolitic magma.     

The structure and stratigraphy of deepwater Sarawak,Malaysia: Implications for tectonic evolution

The structural-stratigraphic history of the North Luconia Province, Sarawak deepwater area, is related to the tectonic history of the South China Sea. The Sarawak Basin initiated as a foreland basin as a result of the collision of the Luconia continental block with Sarawak (Sarawak Orogeny). The foreland basin was later overridden by and buried under the prograding Oligocene-Recent shelf-slope system. The basin had evolved through a deep foreland basin (‘flysch’) phase during late Eocene–Oligocene times, followed by post-Oligocene (‘molasse’) phase of shallow marine shelf progradation to present day.Seismic interpretation reveals a regional Early Miocene Unconformity (EMU) separating pre-Oligocene to Miocene rifted basement from overlying undeformed Upper Miocene–Pliocene bathyal sediments. Seismic, well data and subsidence analysis indicate that the EMU was caused by relative uplift and predominantly submarine erosion between ∼19 and 17 Ma ago. The subsidence history suggests a rift-like subsidence pattern, probably with a foreland basin overprint during the last 10 Ma. Modelling results indicate that the EMU represents a major hiatus in the sedimentation history, with an estimated 500–2600 m of missing section, equivalent to a time gap of 8–10 Ma. The EMU is known to extend over the entire NW Borneo margin and is probably related to the Sabah Orogeny which marks the cessation of sea-floor spreading in the South China Sea and collision of Dangerous Grounds block with Sabah.Gravity modelling indicates a thinned continental crust underneath the Sarawak shelf and slope and supports the seismic and well data interpretation. There is a probable presence of an overthrust wedge beneath the Sarawak shelf, which could be interpreted as a sliver of the Rajang Group accretionary prism. Alternatively, magmatic underplating beneath the Sarawak shelf could equally explain the free-air gravity anomaly. The Sarawak basin was part of a remnant ocean basin that was closed by oblique collision along the NW Borneo margin. The closure started in the Late Eocene in Sarawak and moved progressively northeastwards into Sabah until the Middle Miocene. The present-day NW Sabah margin may be a useful analogue for the Oligocene–Miocene Sarawak foreland basin.     

琼东南盆地构造沉降的时空分布及裂后期异常沉降机制

为考察琼东南盆地构造沉降的时空分布及裂后期异常沉降机制,利用回剥技术计算了盆内68口井的构造沉降史,并选择15口代表井进行拉张应变速率反演及拉张因子计算。结果表明:琼东南盆地构造沉降空间上表现为中央凹陷带和南部凹陷带强于北部凹陷带;时间上在裂陷期出现局部快速沉降-整体慢速沉降—局部快速沉降的阶段特征,进入裂后期逐渐减缓并在15.5～10.5Ma期间减至最低值,但自10.5～5.5Ma以来又明显增大。裂后期异常沉降在盆地东西部都有明显表现,在北部凹陷带较小,在中央凹陷带内往东区有逐渐增大趋势;时间上裂后异常构造沉降随时间增大,增长过程具有快-慢-快的阶段性。分析认为:裂后阶段早期的快速沉降可能是裂陷期非均匀拉张的结果,而晚中新世以后的快速构造沉降主要与岩浆活动有关。     

Tertiary facies architecture in the Kutai Basin,Kalimantan, Indonesia

The Kutai Basin occupies an area of extensive accommodation generated by Tertiary extension of an economic basement of mixed continental/oceanic affinity. The underlying crust to the basin is proposed here to be Jurassic and Cretaceous in age and is composed of ophiolitic units overlain by a younger Cretaceous turbidite fan, sourced from Indochina. A near complete Tertiary sedimentary section from Eocene to Recent is present within the Kutai Basin; much of it is exposed at the surface as a result of the Miocene and younger tectonic processes. Integration of geological and geophysical surface and subsurface data-sets has resulted in re-interpretation of the original facies distributions, relationships and arrangement of Tertiary sediments in the Kutai Basin. Although much lithostratigraphic terminology exists for the area, existing formation names can be reconciled with a simple model explaining the progressive tectonic evolution of the basin and illustrating the resulting depositional environments and their arrangements within the basin. The basin was initiated in the Middle Eocene in conjunction with rifting and likely sea floor spreading in the Makassar Straits. This produced a series of discrete fault-bounded depocentres in some parts of the basin, followed by sag phase sedimentation in response to thermal relaxation. Discrete Eocene depocentres have highly variable sedimentary fills depending upon position with respect to sediment source and palaeo water depths and geometries of the half-graben. This contrasts strongly with the more regionally uniform sedimentary styles that followed in the latter part of the Eocene and the Oligocene. Tectonic uplift documented along the southern and northern basin margins and related subsidence of the Lower Kutai Basin occurred during the Late Oligocene. This subsidence is associated with significant volumes of high-level andesitic–dacitic intrusive and associated volcanic rocks. Volcanism and uplift of the basin margins resulted in the supply of considerable volumes of material eastwards. During the Miocene, basin fill continued, with an overall regressive style of sedimentation, interrupted by periods of tectonic inversion throughout the Miocene to Pliocene.     

Sedimentation of the Neogene–Recent Alaşehir (Gediz) continental graben system used to test alternative tectonic models for western (Aegean) Turkey

The Alaşehir (Gediz) Graben exemplifies clastic sedimentation in a long-lived continental half-graben in a semi-arid setting, developed within relatively incompetent metamorphic rocks. Early Miocene to Recent rift-related sediments are exhumed on both flanks of the graben, allowing detailed three-dimensional study. During the Early Miocene, small fan-delta lobes were shed northwards from the rugged Menderes Metamorphic Massif into a bordering lacustrine basin. During Early to Mid-Miocene time, large alluvial fans prograded northwards into this basin. Through-drainage to the Aegean Sea was established as the basin widened and filled. Discrete lobes of coarse alluvial fan sediments of latest Miocene(?)–Pliocene age, also shedding northwards, are likely to have been climatically influenced. Quaternary alluvium party infills the modern Alaşehır rift basin.The sedimentary information can be used to test two alternative tectonic models for the Alaşehır Graben. In the first model, an E–W graben bounded by high-angle faults was active during latest Miocene(?)–Recent time, whereas earlier Miocene sedimentation was controlled by N–S faulting related to a N–S compressional stress regime. In the second hypothesis, the Alaşehır Graben was initiated much earlier, in the Early Miocene and was then either continuously or episodically active until Recent. Our results, especially facies and palaeocurrent data from alluvial sediments, indicate that clastic sedimentation was controlled by mainly E–W faulting in a N–S stress regime. Assuming the Early Miocene clastic sediments are correctly dated, this supports the second (long-lived extension) model. However, rather than steady-state extension for ca. 15 Ma, the sedimentary evidence and regional context are consistent with a pulsed extension model, whereby initial Early to Mid-Miocene extension and related clastic sedimentation was followed by a second phase of extension in latest Miocene(?)–Pliocene time. The driving force of initial, Early Miocene extension was probably gravity spreading towards a south-Aegean subduction zone, whereas the inferred second extension pulse is seen as being triggered by westward “tectonic escape” of Anatolia towards the extending Aegean back-arc region.     

Sequence Thickness and its Response to Episodic Tectonic Evolution in Paleogene Qikou Sag,Bohaiwan Basin

The sequence stratigraphy framework of Paleogene of Qikou Sag has been built in this paper. The evolution law of episodic subsidence in Qikou Sag has been expounded, with the analysis of the characteristic of sequence thickness, as well as the study of consedimental tectonic activity, subsidence history, paleogeomorphology and the coupling relationship among them. The faults controlling action was the dominant mechanism during rifting stage I , as the depression was the dominant mechanism during rifting stage III, which embodies a process from intense disparity fault depression to integral subsidence. Meanwhile, under the control of regional faulting and later stage depression, subsidence rate centers and paleogeomorphic concave centers are always corresponding to the sequence thickness centers, and the changes of subsidence centers and paleogeomorphology concave centers are consistent with the migration of thickness centers, which presents the restriction, coupling and response among them and clarifies the law that tectonic activity controls the basin fill by means of controlling the subsidence rate and paleogeomorphology from contributing factor angle. On this basis, the dynamic evolution of the composite pattern of structure-subsidence-deposition in the fault controlling actic region during the three rifting stages and their petroleum geological significance has been discussed.     

桂北-桂东加里东期盆地构造沉降史分析

对造山带各地史阶段的沉积盆地进行构造沉降分析,进而探讨其地球动力学过程,是近年来盆地分析的前缘研究之一。本文采用回剥分析技术,分别编绘了桂北、桂东地区加里东期盆地沉降曲线,并进行了构造沉降史分析。结果表明,桂北、桂东加里东期盆地演化均经历了从拉张裂解到挤压闭合的完整过程。但与桂东大瑶山地区相比,桂北兴安地区在裂陷阶段的沉积速率和构造沉降速率明显偏低;热沉降阶段的持续时间偏长;裂陷阶段与前陆挠曲阶段的分界拐点偏晚;前陆挠曲阶段,由构造宁静期的缓慢沉降向构造活动期的快速沉降转化的分界拐点也偏晚。这些差别这一方面说明了两地区具有不同的构造背景,另一方面也反映了华夏板块由南东逐渐地向北西扬子板块靠拢,沉积盆地相应地向西北迁移的动力学过程。     

The rift origin of the Vilyui basin (East Siberia), from reconstructions of sedimentation and mechanical mathematical modeling

Results of modeling of the formation of the Vilyui sedimentary basin are presented. We combine backstripping reconstructions of sedimentation and thermal regime during the subsidence with a numerical simulation based on the deformable solid mechanics. Lithological data and stratigraphic sections were used to “strip” the sedimentary beds successively and calculate the depth of the stratigraphic units during the sedimentation. It is the first time that the evolution of sedimentation which is nonuniform over the basin area has been analyzed for the Vilyui basin. The rift origin of the basin is proven. We estimate the spatial distribution of the parameters of crustal and mantle-lithosphere extension as well as expansion due to dike intrusion. According to the reconstructions, the type of subsidence curves for the sedimentary rocks of the basin depends on the tectonic regime of sedimentation in individual basins. The backstripping analysis revealed two stages of extension (sediments 4–5 km thick) and a foreland stage (sediments > 2 km thick). With the two-layered lithosphere model, we conclude that the subcrustal layer underwent predominant extension (by a factor of 1.2–2.0 vs. 1.1–1.4 in the crust). The goal of numerical experiments is to demonstrate that deep troughs can form in the continental crust under its finite extension. Unlike the oceanic rifting models, this modeling shows no complete destruction or rupture of the continental crust during the extension. The 2D numerical simulation shows the possibility of considerable basement subsidence near the central axis and explains why mafic dikes are concentrated on the basin periphery.     

中国大陆东部晚中生代构造活化及其演化过程

与中生代中期造山型构造活化不同．晚中生代期间,中国大陆东部的构造活化表现为规模宏大的断陷盆地系、变质核杂岩、花岗岩浆侵位、火山岩喷发以及沿大型走滑断层的转换伸展为特征的大陆裂陷作用。根据岩浆活动、盆地的充填记录,构造格架和盆地的沉降史分析,可以将裂陷作用划分为两个大的阶段,即由兴安岭群火山喷发为代表的第一阶段和以巴彦花群含煤、油碎屑岩系为代表的断陷盆地形成阶段。盆地沉降史回剥研究表明,裂陷作用第二阶段断陷盆地的发育受控于次一级的幕式构造作用过程。此外．对晚中生代裂陷作用的动力学背景的探讨需要阐明岩石圈的深部过程和构造应力场的反转这个两个重要的问题。