前陆盆地层序地层学研究简介

前陆盆地层序地层学是将层序地层学理论应用于构造活动的前陆盆地分析的一个特例。前陆盆地三级层序成因并非受全球统一的海平面变化控制，而是与盆缘造山带区域本报特约记者运动、盆内沉积作用和相对海平面变化的联合作用有关，代表了前陆分地一个成盆期的不同发育阶段。层序界面是相对海平面下降和区域构造隆的联合作用面。在盆地演化的不对称沉降阶充填阶段，邻造山带区为低水位浊积扇沉积层序；远离造山带区，低水位体系域不发育     

Sedimentary evolution of basins in mobile belts: examples from the Tertiary terrigenous sequences of the Peloritani Mountains (NE Sicily)

The Tertiary covers of the Peloritani Mountain Belt (NE Sicily) provide a complete stratigraphical record of tectonic events related to collision in the Central Mediterranean region. The tectonosedimentary evolution is inferred from interpretation of new field data and indicates various stages of polyphase deformation. The Peloritani Mountain Belt is composed mostly of crystalline units representing the active margin of the European Plate that was thrust over the descending African Plate during the Tertiary. Late Eocene-early Oligocene syn-orogenic deposition took place within a fore-arc basin located along the leading edge of the Peloritani Mountain Belt. From the late Oligocene to late Langhian, terrigenous deposition occurred throughout the mountain belt and extended into perched basins, located in southern areas. The basin was fed from the north, from source areas located in the hinterland of the orogenic belt. Deposition was controlled by a combination of active thrusting, regional subsidence and sea-level change. During the early Serravallian sudden tectonic inversion took place, associated with collapse of hinterland areas and uplift of former low-lying southern areas of the mountain belt. These processes were related to onset of opening of the Tyrrhenian Sea that was completed during the Serravallian-Tortonian, and resulted in the deposition of a northwestward prograding clastic fan, fed by source areas located in the southern area of the mountain belt. This setting characterized Messinian and Plio-Pleistocene deposition, and was controlled by both active tectonics and eustasy. The Recent evolution of the Peloritani Mountain Belt is characterized by major progressive uplift of the southern margins of the Tyrrhenian Basin, and local active subsidence related to downfaulting. Such processes resulted in the uplift of mid-Pleistocene fan-delta deposits and late Pleistocene marine terraces deposits to various altitudes above present sea-level.     

前陆盆地沉降机理和地层模型

前陆盆地形成的主要原因是造山带负载导致的岩石圈挠曲。逆冲作用造成地壳增厚,造山带的巨大质量又导致下部岩石圈的区域均衡沉降,从而临近和平行于造山带发育了凹陷。另外,前陆盆地的演化也受到沉积物供应、盆地内沉积物扩散能力、岩石圈强度、造山带逆冲速率、全球海平面变化、和俯冲有关的动力沉降及俯冲负载等众多其它因素的影响。本文阐述了这些因素与前陆盆地沉降的关系,介绍了与幕式逆冲有关的地层模型和欠补偿-过补偿地层模型。希望本文能够对中国西北地区前陆盆地的研究起到一定的借鉴意义。     

Fluvial sequences and basin development in the northern Galilee Basin

In the northern Galilee Basin, 10 third-order depositional sequences have been recognised in multi-suite geophysical logs of 16 wells and boreholes. Sequences can be subdivided into genetic systems tracts characterised by geometry, facies associations, types of bounding surface, parasequence set distribution and position within the sequence. Stacking trends of parasequence sets may be observed as a shift in the sand or shale base line. These sequences reflect basinal and hinterland tectonics with a subordinate climate and sea-level cycle signature. The initial development of the northern Galilee Basin in the upper Carboniferous reflects thermal subsidence that characterised the underlying Drummond Basin. This subsidence is overprinted by the commencement of foreland-basin tectonics associated with extension in the Bowen Basin. The foreland tectonics waned before a major regional uplift occurred in the northern Galilee Basin in the middle Permian. This uplift is associated with an early phase of the Hunter–Bowen Orogeny. A quiescent period where accommodation is controlled by sea-level changes is reflected in extensive development of mires. Renewed episodic contraction overprinted on thermal sag subsidence in the Lower Triassic reflects far-field tectonics associated with the Hunter–Bowen Orogeny. In the Upper Triassic, an end-phase event of the Hunter–Bowen Orogeny inverted the Galilee Basin.     

关于造山带动力沉积学若干问题的思考

造山带动力沉积学是造山带地质学和大陆动力学研究的重要方面。造山带动力沉积学研究的重要基础是识别造山带的原型沉积盆地,认识其大地构造沉积相和原型沉积盆地的演化。造山带动力沉积学研究的主要内容包括造山带区域地层学、沉积学、大地构造学、造山带原型盆地的充填序列或构造层序、古地理和古海洋及建立沉积盆地的动力模式。其研究方法涉及造山带原型盆地的物源和组分分析、沉积相和沉积体系及沉积构型分析、充填序列和构造层序分析、古流向和古地理分析、沉积厚度和沉降分析以及沉积盆地动力模拟等。     

Tectonic evolution of the Southern Gulf of Suez, Egypt: a comparison between depocenter and near peripheral basins

The sedimentary pattern of the southern Gulf of Suez, Egypt, especially during the Cenozoic rift stage, was controlled mainly by tectonic activities (subsidence and uplift) and sea level change. The stratigraphic record of the southern Gulf of Suez can be divided into two megasequences: pre-rift and syn-rift. The pre-rift megasequence can be viewed as two distinctive depositional regimes, clastic rocks of continental to braided stream environment during Cambrian and open marine transgression extended from Upper Cretaceous till Eocene. The syn-rift deposits showed a distinctive contrast between the depocenter and peripheral basins. This difference can be shown clearly on the sedimentary sequence of Hilal and Shoab Ali oilfields. The syn-rift megasequence can be differentiated in relation to rift evolution into the following stages: initial rift stage with low subsidence rate, main rift stage with maximum subsidence rate, quiescence stage with the slowest subsidence rate throughout the rift evolution, evaporite stage with restriction conditions, and Pliocene–Recent stage with shallow marine condition.     

Foredeep submarine fans and forebulge deltas: orogenic off-loading in the underfilled Karoo Basin

Third-order sequence stratigraphic analysis of the Early Permian marine to continental facies of the Karoo Basin provides a case study for the sedimentation patterns which may develop in an underfilled foreland system that is controlled by a combination of supra- and sublithospheric loads. The tectonic regime during the accumulation of the studied section was dominated by the flexural rebound of the foreland system in response to orogenic quiescence in the Cape Fold Belt, which resulted in foredeep uplift and forebulge subsidence. Coupled with flexural tectonics, additional accommodation was created by dynamic loading related to the process of subduction underneath the basin. The long-wavelength dynamic loading led to the subsidence of the peripheral bulge below base level, which allowed for sediment accumulation across the entire foreland system.A succession of five basinwide regressive systems tracts accumulated during the Artinskian (5 My), consisting of foredeep submarine fans and correlative forebulge deltas. The progradation of submarine fans and deltaic systems was controlled by coeval forced and normal regressions of the proximal and distal shorelines of the Ecca interior seaway respectively. The deposition of each regressive systems tract was terminated by basinwide transgressive episodes, that may be related to periodic increases in the rates of long-wavelength dynamic subsidence.     

Structure and tectonic history of the foreland basins of southernmost South America

The common elements and differences of the neighboring Austral (Magallanes), Malvinas and South Malvinas (South Falkland) sedimentary basins are described and analyzed. The tectonic history of these basins involves Triassic to Jurassic crustal stretching, an ensuing Early Cretaceous thermal subsidence in the retroarc, followed by a Late Cretaceous–Paleogene compressional phase, and a Neogene to present-day deactivation of the fold–thrust belt dominated by wrench deformation. A concomitant Late Cretaceous onset of the foreland phase in the three basins and an integrated history during the Late Cretaceous–Cenozoic are proposed. The main lower Paleocene–lower Eocene initial foredeep depocenters were bounding the basement domain and are now deformed into the thin-skinned fold–thrust belts. A few extensional depocenters developed in the Austral and Malvinas basins during late Paleocene–early Eocene times due to a temporary extensional regime resulting from an acceleration in the separation rate between South America and Antarctica preceding the initial opening of the Drake Passage. These extensional depocenters were superimposed to the previous distal foredeep depocenter, postdating the initiation of the foredeep phase and the onset of compressional deformation. Another pervasive set of normal faults of Paleocene to Recent age that can be recognized throughout the basins are interpreted to be a consequence of flexural bending of the lithosphere, in agreement with a previous study from South Malvinas basin. Contractional deformation was replaced by transpressive kinematics during the Oligocene due to a major tectonic plate reorganization. Presently, while the South Malvinas basin is dominated by the transpressive uplift of its active margin with minor sediment supply, the westward basins undergo localized development of pull-apart depocenters and transpressional uplift of previous structures. The effective elastic thickness of the lithosphere for different sections of each basin is calculated using a dynamic finite element numerical model that simulates the lithospheric response to advancing tectonic load with active sedimentation.     

层序地层学研究进展

近代沉积地质学研究的对象和目的早已超越了沉积岩石学、相分析和沉积环境演替的经典研究，而是把发生沉积作用的堆积场所──盆地．放在全球沉积地壳演化的时空坐标上，通过正负沉积记录寻求有成因联系的沉积和构造综合体在地质历史中各种事件的铸记，恢复它在全球古板块和古地理的位置．进而探索沉积地壳演化和地球起源的证据。在科学技术高速发展的今天．地学领域也具有明显的时代特征：一是地质学中各学科的专业化、计算机化和定量化；另一特征则是多学科的渗透化。其中层序地层学研究在近代地学领域中具有里程碑意义的重大进展是追踪对比全球沉积记录和全球古地理再造的重要研究途径。     

Deep-water clastic evaporites deposition in the Messinian Adriatic foredeep (northern Apennines,Italy): did the Mediterranean ever dry out?

A new genetic facies model for deep-water clastic evaporites is presented, based on work carried out on the Messinian Gessoso-solfifera Formation of the northern Apennines during the last 15 years. This model is derived from the most recent siliciclastic turbidite models and describes the downcurrent transformations of a parent flow mainly composed of gypsum clasts. The model allows clearer comprehension of processes controlling the production and deposition of clastic evaporites, representing the most common evaporite facies of the northern Apennines, and the definition of the genetic and stratigraphic relationship with primary shallow-water evaporites formed and preserved in marginal settings. Due to the severe recrystallization processes usually affecting these deposits, petrographic and geochemical analyses are needed for a more accurate interpretation of the large spectrum of recognized gravity-driven deposits ranging from debrisflow to low-density turbidites. Almost all the laminar ‘balatino’ gypsum, previously considered a deep-water primary deposit, is here reinterpreted as the fine-grained product of high to low-density gravity flows. Facies associations permit the framing of the distribution of clastic evaporites into the complex tectonically controlled depositional settings of the Apennine foredeep basin. The Messinian Salinity Crisis occurred during an intense phase of geodynamic reorganization of the Mediterranean area that also produced the fragmentation of the former Miocene Apennine foredeep basin. In this area, primary shallow-water evaporites equivalent to the Mediterranean Lower Evaporites, apparently only formed in semi-closed thrust-top basins like the Vena del Gesso Basin. The subsequent uplift and subaerial exposure of such basins ended the evaporite precipitation and promoted a widespread phase of collapse leading to the resedimentation of the evaporites into deeper basins. Vertical facies sequences of clastic evaporites can be interpreted in terms of the complex interplay between the Messinian tectonic evolution of the Apennine thrust belt and related exhumation–erosional processes. The facies model here proposed could be helpful also for better comprehension of other different depositional and geodynamic contexts; the importance of clastic evaporites deposits has been overlooked in the study of other Mediterranean areas. Based on the Apennine basins experience, it is suggested here that evaporites diffused into the deeper portions of the Mediterranean basin may consist mainly of deep-water resedimented deposits rather than shallow-water to supratidal primary evaporites indicative of a complete basin desiccation.     

中国前陆盆地构造地质特征综述与油气勘探

中国特定环境下发育的前陆盆地和冲断带在地质构造上具有许多的特殊性。在综述前人认识的基础上,笔者通过对中国前陆盆地的构造演化历程、沉积充填特征、构造成因及其空间分布规律、构造变形特征等的研究,提出了中国前陆盆地构造地质发育的5个主要特征:(1)两种不同性质的原型盆地发生正反转的叠合性,即挤压构造下作为“本体”的前陆层序与拉张构造下作为“基础”的裂谷、断陷盆地之间的叠置;(2)显生宙以来中国大陆先后发生了4期前陆冲断构造演化的多期性,它们分别是加里东晚期、海西晚期、印支期和喜马拉雅晚期;(3)基于小克拉通基底拼贴后在造山带前缘复活再生的继承性,即统一拼合大陆内部的构造变形导致古造山带的复活,在古造山带边缘发育新生代前陆盆地或前陆冲断带;(4)在空间分布上受环青藏高原巨型盆山体系控制发生陆内变形的系统性,在环青藏高原巨型盆山体系内构造变形强度、盆地沉降幅度、盆山耦合程度等从内环向外环依次降低,从古造山带向克拉通方向构造变形强度依次降低,构造变形样式逐渐简单、构造变形时间依次变新;(5)前陆冲断带的构造样式由于受边界力学条件和沉积地层介质作用而具有多变性,存在沉积盖层内脆性变形的断层相关褶皱、造山带前缘韧性变形的基底卷入构造、与走滑构造相伴生的基底卷入的断层相关褶皱、盆地内部塑性变形的盐构造。正是因为上述地质构造的特殊性,决定了油气聚集与分布特征的规律性和复杂性,由此提出了相应的一些构造地质研究与油气勘探工作的建议。     

下扬子地区早古生代晚期前陆盆地沉积特征与盆山过程

下扬子地区从晚奥陶世开始沉积特征发生了明显转变,从浅海相转变为三角洲相沉积.这一沉积特征转变与早古生代晚期经历的强烈造山事件密切相关.通过下扬子地区晚奥陶世到志留纪沉积序列的沉积学和碎屑锆石年代学研究,揭示沉积盆地的性质及其时空演化过程,探讨沉积盆地发育与造山带隆升剥蚀之间的关系.下扬子地区早古生代晚期沉积学特征从东南向西北岩性由岩屑砂岩变为石英砂岩,粒度由粗粒变为细粒;沉积厚度等值线具有明显的不对称性,靠近东南等值线密,且沉积厚度大;往西北等值线稀疏,且沉积厚度小;沉积中心呈狭长带状分布,并从东南向西北方向迁移;具有前陆盆地的沉积特征.上奥陶统到中志留统的碎屑锆石以900～720Ma的年龄为主,指示物源以下伏新元古代晚期裂谷层序为主;从早志留世高家边组开始,450～420Ma碎屑锆石年龄出现并逐渐增多,表明同造山岩浆岩被剥露地表并开始提供物源;碎屑锆石中没有出现明显的代表华夏地块基底1.9～1.7Ga的特征年龄峰值,表明华夏地块不是下扬子地区早古生代晚期前陆盆地的主要物源区.下扬子地区前陆盆地从晚奥陶世开始沉降,晚奥陶世的构造沉降速率超过了沉积物的供给速率,前渊沉积了巨厚的浅海相泥岩夹粉砂岩和砂岩;晚奥陶世末造山带持续隆升并向西北方向扩展,沉积速率加快,沉积物粒度明显变粗,沉积相也由浅海相转变成三角洲前缘相;早志留世开始埋深较大的同造山岩浆岩开始遭受剥蚀,导致前陆盆地中450～420 Ma的碎屑锆石含量明显增加.     

Dynamic stratigraphy of composite peripheral unconformity in a foredeep basin

This study employs facies analysis and basic principles of sequence stratigraphy to correlate isolated outcrop sections and reveal the depositional history of the Chmielnik Formation – a prominent mid‐Serravalian clastic wedge formed on the basinward forebulge flank of the Polish Carpathian Foredeep. The coarse‐grained clastic wedge, up to 30 m thick and spanning ca 1·1 Ma within biozone NN6, consists of fluvio‐deltaic, foreshore and shoreface deposits with a range of large littoral sand bars, all enveloped in muddy offshore‐transition deposits. Its dynamic stratigraphy indicates rapid shoreline shifts and environmental changes due to the interplay of forebulge tectonism, sediment supply and third‐order eustatic cycles. A similar interplay of tectonism and eustasy is recognizable in the whole middle Miocene sedimentary succession deposited on the forebulge flank, demonstrating an extreme case of an accommodation‐controlled shelf and indicating tectonic cycles of the forebulge uplift and subsidence spanning ca 800 to 900 ka. The episodes of forebulge uplift correlate with the main pulses of orogen thrusting. The resulting composite peripheral unconformity differs markedly from the idealized model of a ‘steady‐state’ stepwise onlap driven by forebulge continuous retreat. It is concluded that the foredeep peripheral unconformities, instead of being simplified in accordance with this idealized model, should rather be studied in detail because they bear a valuable high‐resolution record of regional events and give unique insights into the local role of tectonics, eustasy and sediment supply.     

楚雄中生代前陆盆地的构造沉降史研究

云南楚雄盆地位于场子陆块的西南边缘,为一典型的中生代周缘前陆盆地,盆地演化阶段明显,晚三叠世为前陆早期复理石沉积,侏罗纪则为前陆晚期磨拉石沉积。对盆地构造沉降史研究后笔者认为：①晚三叠世复理石沉积盆地构造沉降幅度巨大,沉降与沉积中心位于盆地最西部,紧邻古哀牢山造山带,沉积体呈形楔形展布;③侏罗纪磨拉石沉积盆地构造沉降和沉积中心以及前缘隆起向内陆方向迁移明显;③中生代构造快速沉降的沉积体的楔形展布表     

沉积盆地同沉积构造活动的沉积记录

同构造沉积盆地的沉积作用与构造环境及其活动性质有着内在的统一性,尽管控制沉积作用的因素很多(诸如气候、物源等),但最基本的因素乃是同沉积作用的构造活动,它控制着沉积体的分布、厚度、相型等。甚至不少沉积体是在两种或三种构造环境下发生的,因而有着纵横交替、相互更叠的复杂层序。而作为特殊沉积作用的沉积矿产,则更显著地制约于同沉积构造活动,尤其作为导矿构造的基底构造以及盆地演化中的控制性构造,则是寻找隐伏矿产的一     

塔里木盆地腹地玛扎塔格地区新近纪砂岩组分和重矿物组合特征及物源分析

发育于塔里木盆地腹地——玛扎塔格地区的新近纪沉积地层出露良好,保存了其物源区造山带的隆升剥蚀信息。利用古水流、砂岩碎屑组构和重矿物组合特征等研究方法,结合研究区的区域构造演化,探讨玛扎塔格地区晚新生代以来古地貌格局及沉积物源区隆升剥蚀的沉积响应关系。结果表明该研究区的古地貌总体格局为西高东低,沉积物源在上新世早期之前主要来自于西昆仑造山带和帕米尔造山带,而到了上新世以来其沉积物源主要来自于帕米尔造山带,并且在上新世早期,物源区发生明显的构造隆升运动,更新世期间物源区出现快速隆升剥蚀构造事件。     

Provenance analysis as a key to orogenic exhumation: a case study from the East Carpathians (Romania)

Provenance analysis of the sediments from foredeep basins is crucial in understanding the contemporaneous orogenic exhumation processes. We report in this paper complex sediment provenance analysis using sandstone petrography and mudstone geochemistry, combined with magnetic susceptibility of the Upper Miocene to Pliocene deposits from Focşani foredeep basin (Romania). Data show a change of source area between 5 and 6 Ma, from an active volcanic arc towards a recycled orogenic belt, concurrent with an important increase of accumulation rate. This change was triggered by exhumation and erosion of the outer nappes from East Carpathians.     

Structural style of the Marathon thrust belt, West Texas

The Marathon portion of the Ouachita thrust belt consists of a highly deformed allochthonous wedge of Cambrian-Pennsylvanian slope strata (Marathon facies) that was transported to the northwest and emplaced over Pennsylvanian foredeep sediments. The foredeep strata in turn overlie early-middle Paleozoic shelfal sediments which are deformed by late Paleozoic basement-involved reverse faults. The Dugout Creek thrust is the basal thrust of the allochthon. Shortening in this sheet and overlying sheets is 80%. Steep imbricate faults link the Dugout Creek thrust to upper level detachments forming complex duplex zones. Progressive thrusting and shortening within the allochthon folded the upper level detachments and associated thrust sheets. The Caballos Novaculite is the most competent unit within the Marathon facies and controlled development of prominent detachment folds.Deeper imbricate sheets composed of the Late Pennsylvanian foredeep strata, and possibly early-middle Paleozoic shelfal sediments developed concurrently with emplacement of the Marathon allochthon and folded the overlying allochthon. Following termination of thrusting in the earliest Permian, subsidence and deposition shifted northward to the Delaware, Midland and Val Verde foreland basins.     

Evolution of the Neogene Andean foreland basins of the Southern Pampas and Northern Patagonia (34°–41°S), Argentina

The Pampas plain (30°–41°S) has historically been considered as a sector that evolved independently from the adjacent Andean ranges. Nevertheless, the study of the Pampas showed that it is reasonable to expect an important influence from the Andes into the extraandean area. The Pampas plain can be divided into two sectors: the northern portion, adjacent to the Pampean Ranges, has been studied by Davila (2005, 2007, 2010). The southern sector (34°–41°S) is the objective of the present work. The study of this area allowed to characterize two separate foreland basins: the Southern Pampa basin and the Northern Patagonian basin. The infill is composed of Late Miocene and Pliocene units, interpreted as distal synorogenic sequences associated with the late Cenozoic Andean uplift at this latitudinal range. These foreland basins have been defined based on facies changes, distinct depositional styles, along with the analysis of sedimentary and isopach maps. The basins geometries are proposed following De Celles and Gilles (1996) taking into account the infill geometry, distribution and grain size. In both cases, these depocenters are located remarkably far away from the Andean tectonics loads. Therefore they cannot be explained with short-wave subsidence patterns. Elastic models explain the tectonic subsidence in the proximal depocenters but fail to replicate the complete distal basins. These characteristics show that dynamic subsidence is controlling the subsidence in the Southern Pampas and Northern Patagonian basins.