台湾西部前陆盆地和帝汶海前陆盆地的比较学研究

台湾西部前陆盆地和帝汶海前陆盆地均是新生代环太平洋巨型沟-弧-盆体系的一部分。Huang et al.(2000)认为,帝汶海前陆盆地目前相当于台湾南部陆海域所处的弧-陆碰撞的初始阶段。我们认为,该研究中存在着一种潜在的逻辑上的矛盾。在研究单个前陆盆地时,造山过程和板块的挠曲特性均会成为关注的焦点;而一旦进行盆地之间的对比研究,则往往会倾向于关注造山过程、机制以及构造现象的异同等,并由此得出相应结论,却忽视了在现象异同的背后所隐藏着的板块挠曲特性所起的控制性作用。事实上,帝汶海前陆盆地和台湾西部前陆盆地的根本差异并不在其造山作用和过程,而在于其板块挠曲特性的巨大差异。正是这种差异决定了二者具有完全不同的演化特性,构造、层序上的异同只是这种差异的外在体现。忽视这种差异,仅根据构造上的异同以推断前陆的演化过程会导致认识的偏差。     

前陆、前陆盆地和前陆盆地系统

前陆是指与造山带相毗连的构造相对稳定地区，造山带的岩石向着它俯冲成掩覆，可分为三种类型，即曾为被动型大陆边缘的（Ⅰ型），曾与沟－弧系有关的（Ⅱ型）和陆内造山带前方的（Ⅲ型）。前陆盆地为沿造山带前陆区分布的线状压性深坳陷，可分为周缘前陆盆地，弧后前陆盆地和陆内前陆盆地三种类型。前陆盆地系统是一个沿造山带分布的长条状的潜在沉积可容空间，可划分为楔顶，前渊，前隆和隆后等4个部分。     

柴达木盆地北缘早奥陶世陆 弧碰撞及弧后前陆盆地——来自碎屑岩地球化学的证据

奥陶纪是柴达木盆地北缘早古生代碰撞造山演化的重要时期,柴达木地块与滩间山岛弧碰撞起始时限以及欧龙布鲁克海盆盆地类型、构造-古地理格局一直存在争议。本文在对欧龙布鲁克地块早奥陶世碎屑岩沉积野外观测及室内分析的基础上,测试了30个砂泥岩样品的主量元素、微量元素及稀土元素含量。结果表明,石灰沟组碎屑岩建造具有快速堆积、低成分成熟度、低结构成熟度的特征;该套碎屑岩沉积于活动大陆边缘背景下的弧后前陆盆地,碎屑物质来自南部由大陆上地壳与岛弧物质组成的上隆基底;早奥陶世(488~472 Ma)柴达木地块与滩间山岛弧陆-弧碰撞已经开始,但陆-弧碰撞起始时间不会早于493Ma。在此基础上,结合前人研究成果,认为早古生代欧龙布鲁克地块处于滩间山岛弧北部,盆地沉降、沉积演化受柴达木盆地北缘洋盆俯冲及柴达木地块-滩间山岛弧碰撞控制,寒武纪发育弧后伸展盆地,奥陶纪初期转为弧后挤压前陆盆地,弧后伸展与弧后挤压、沉积体系转换发生在490~480Ma之间。该成果从沉积学角度为柴达木盆地北缘陆-弧碰撞起始时限提供了新的制约。     

下扬子地区沿江前陆盆地形成的构造控制

华北板块与扬子板块沿大别－胶南造山带的陆－陆碰撞使造 山带侧的扬子板块成为前陆变形带,并在其上发育了沿江前陆盆地。沿江前陆盆地初始继承性发育于下扬子区海退末期残留的陷区,随后于黄马青期受北界滁河断裂与南界江南断裂的对冲控制而成为双向压隐型盆地。     

盆山耦合与前陆盆地成藏区带分析

经济全球化导致油气勘探全球化,板块学说在理论上提供全球油气勘探基础,亚洲大陆与北美大陆盆山体系在实践上提供全球油气勘探经验。盆山耦合体系存在3类造山带与3类前陆盆地即:(1)俯冲造山带与弧后前陆盆地;(2)碰撞造山带与周缘前陆盆地;(3)陆内造山带与陆内前陆盆地。前陆盆地成藏区带勘探中,在空间上应将造山带前麓褶皱—冲断带层与前陆盆地作为统一应变场,在时间上应将前冲断作用沉积层序,同冲断作用沉积层序和后冲断作用沉积层序作为整体来进行勘探。     

扬子周缘前陆盆地演化及类型

扬子周缘前陆盆地的形成是扬子陆块周缘多次裂解，增生过程的产物，其形成演化可分为两个阶段：早期（Ｏ３－Ｄ）为碰撞型前陆盆地演化阶段；晚期（Ｔ３－Ｋｚ）为陆内俯冲型前陆盆地演化阶段，构成了复合叠加的前陆盆地，碰撞型前陆盆地的形成代表一个从洋壳消碱直至闭合的演化旋回，一般具有：代表早期俯冲造山作用所残留的蛇绿岩，混杂堆积带；代表碰撞早期形成的复理石前陆盆地；代表碰撞后期的磨拉石前陆盆地，因而剖面上具有双     

前陆盆地类型及褶皱－冲断层样式

Ｄｉｃｋｉｎｓｏｎ正式引入前陆盆地这一术语并提出周缘前陆盆地和弧后前陆盆地两种成因类型。根据中国西北部盆地的构造位置，笔者又提出再生前陆盆地和分割前陆盆地两种类型。按前陆盆地中褶皱－冲断层关系可以分出系列褶皱－冲断层样式：从断弯褶皱、断展褶皱到断滑褶皱。褶皱－冲断层样式的发育决定于最初为应力轨迹所切割的不稳定面，而确定应力轨迹的主要因素是埋藏深度和区域构造作用。因此断滑褶皱大多数发育在地下浅处，而断弯褶皱主要发育在地下较深处。     

前陆盆地类型及褶皱－冲断层样式

Ｄｉｃｋｉｎｓｏｎ正式引入前陆盆地这一术语并提出周缘前陆盆地和弧后前陆盆地两种成因类型。根据中国西北部盆地的构造位置，笔者又提出再生前陆盆地和分割前陆盆地两种类型。按前陆盆地中褶皱－冲断层关系可以分出系列褶皱－冲断层样式：从断弯褶皱、断展褶皱到断滑褶皱。褶皱－冲断层样式的发育决定于最初为应力轨迹所切割的不稳定面，而确定应力轨迹的主要因素是埋藏深度和区域构造作用。因此断滑褶皱大多数发育在地下浅处，而断弯褶皱主要发育在地下较深处。     

塔里木库车陆内前陆盆地及其勘探意义

前陆盆地按大地构造位置、发育时间及成因类型等可以划分为周缘前陆盆地、弧后前陆盆地和陆内前陆盆地,新生代库车前陆盆地即属于陆内前陆盆地.库车前陆盆地油气资源丰富,成藏条件优越,是塔里木盆地油气资源极其重要的组成部分.分析库车陆内前陆盆地构造特征及其控油作用对揭示我国中-西部地区中-新生代前陆盆地的油气成藏及分布具有重要意义.     

陆-陆碰撞造山带双前陆盆地模式——来自大别山、喜马拉雅和乌拉尔造山带的证据

大陆碰撞造山带不同的构造演化阶段往往形成不同成因类型的周缘前陆盆地 (系统 )。根据对几个典型大陆造山带的研究 ,我们把大陆碰撞造山带的构造演化过程分为陆 -陆拼接和大规模陆内逆冲推覆 (陆内俯冲 )两个阶段 ;早期陆 -陆拼接阶段直接在俯冲板块被动大陆边缘基础上形成的前陆盆地称为“原前陆盆地” ,后期大规模陆内逆冲 -推覆 (或陆内俯冲 )阶段在俯冲板块内部形成的前陆盆地称为“远前陆盆地”(它比原前陆盆地距主缝合带远 )。原前陆盆地和远前陆盆地是同一大陆碰撞造山带不同构造演化阶段的产物 ,是两种不同成因类型的周缘前陆盆地 ,它们构成了同一大陆造山带的双前陆盆地 ,而不是传统概念的单一成因类型前陆盆地。     

Sedimentology and foreland basin paleogeography during Taiwan arc continent collision

The Western foreland basin in Taiwan originated through the oblique collision between the Luzon volcanic arc and the Asian passive margin. Crustal flexure adjacent to the growing orogenic load created a subsiding foreland basin. The sedimentary record reveals progressively changing sedimentary environments influenced by the orogen approaching from the East. Based on sedimentary facies distribution at five key stratigraphic horizons, paleogeographic maps were constructed. The maps highlight the complicated basin-wide dynamics of sediment dispersal within an evolving foreland basin.The basin physiography changed very little from the middle Miocene (∼12.5 Ma) to the late Pliocene (∼3 Ma). The transition from a passive margin to foreland basin setting in the late Pliocene (∼3 Ma), during deposition of the mud-dominated Chinshui Shale, is dominantly marked by a deepening and widening of the main depositional basin. These finer grained Taiwan derived sediments clearly indicate increased subsidence, though water depths remain relatively shallow, and sedimentation associated with the approach of the growing orogen to the East.In the late Pleistocene as the shallow marine wedge ahead of the growing orogen propagated southward, the proximal parts of the basin evolved into a wedge-top setting introducing deformation and sedimentation in the distal basin. Despite high Pleistocene to modern erosion/sedimentation rates, shallow marine facies persist, as the basin remains open to the South and longitudinal transport is sufficient to prevent it from becoming overfilled or even fully terrestrial.Our paleoenvironmental and paleogeographical reconstructions constrain southward propagation rates in the range of 5–20 km/Myr from 2 Ma to 0.5 Ma, and 106–120 km/Myr between late Pleistocene and present (0.5–0 Ma). The initial rates are not synchronous with the migration of the sediment depocenters highlighting the complexity of sediment distribution and accumulation in evolving foreland basins.     

Sedimentology of early Pliocene sandstones in the south-western Taiwan foreland: Implications for basin physiography in the early stages of collision

This work presents sedimentological observations and interpretations on three detailed sections of the Pliocene Yutengping/Ailiaochiao formations, deposited in the early stages of collision in Taiwan. Seven facies associations record paleoenvironments of deposition ranging from nearshore to lower offshore with a strong influence of tidal reworking, even in shelfal sub-tidal environments, and a pro-delta setting characterized by mass-flows. The association of shallow facies of the upper offshore to lower shoreface with pro-delta turbidite facies sourced in the orogen to the east suggests a peculiar setting in which turbidite deposition occurred below wave base but on the shelf, in water depths of probably less than 100 m. This adds to the examples of “shallow turbidites” increasingly commonly found in foreland basins and challenges the classical view of a “deep” early underfilled foreland basin. Time series analysis on tidal rhythmites allow us to identify a yearly signal in the form of periodic changes of sand-supply, energy and bioturbation that suggests a marked seasonality possibly affecting precipitation and sediment delivery as well as temperature. The Taiwan foreland basin may also present a potentially high-resolution record in shallow sediments of the early installation of monsoonal circulation patterns in east Asia. We confirm partly the paleogeography during the early stages of collision in Taiwan: the Chinese margin displayed a pronounced non-cylindrical geometry with a large basement promontory to the west in place of the modern Taiwan mountain range. Collision in Taiwan may have happened at once along the whole length of the modern mountain range, instead of progressively from north to south as classically considered.     

Development of tectonostratigraphy in distal part of foreland basin in southwestern Taiwan

In the young and active tectonic belt of southwestern Taiwan, reconstructed stratigraphy in the distal part of the foreland basin reveals at least two regional unconformities with the younger ones covering the areas farther from the mountain belt. In contrast with the previously proposed monotonous basin development, the temporal–spatial distribution of the unconformities indicates the back-and-forth migration of the foreland basin margin. Three distinct episodes of rapid subsidence during the foreland basin development have also been identified. The onset of the basin development can be well constrained by the initial rapid subsidence at 4.4–4.2 Ma, which happened only in the proximal part of the basin. This was followed by two younger episodes of rapid subsidence events at 2–1.8 Ma and 0.45 Ma, which were encountered initially in the areas progressively farther from the orogenic belt.We propose a model of episodic tectonic evolution in the distal part of the foreland basin in southwestern Taiwan. During each episode of rapid subsidence, uplifting that corresponds to the forebulge began with a concurrent rapid subsidence in the areas closer to the basin center and was followed by rapid subsidence and deposition of widespread strata onlapping toward the basin margin. Part of the widespread strata and its overlying deposits would be eroded in the beginning of the next episode when the forebulge shifted toward the orogenic belt. In general, rate of forebulge migrating away from the orogenic belt during the early stage was slower than that derived from a previously proposed kinematic model of a steady migration of the orogenic belt. This might be due to a rifted and weaker lithosphere beneath the foreland basin. Once the foreland basin migrated onto the less stretched lithosphere, the basin would expand rapidly into the craton.     

The trinity of depositional phase of foreland basins: An example from the western Taiwan foreland basin

Due to oblique arc-continent collision, the west-ern Taiwan foreland basin has evolved into three dis-tinct subbasins: an over-filled basin proximal to the Taiwan orogen, mainly distributed in the Western Foothhils and Coastal Plain provinces, a filled basin occupying the shallow Taiwan Strait continental shelf west of the Taiwan orogen and an under-filled basin distal to the Taiwan orogen in the deep marine Kaop-ing Slope offshore southwest Taiwan, respectively. The over-filled depositional phase is dominated by fluvial environments across the structurally controlled piggy-back basins. The filled depositional phase in the Taiwan Strait is characterized by shallow marine en-vironments and is filled by Pliocene-Quaternary sedi-ments up to 4,000 m thick derived from the Taiwan orogen with an asymmetrical and wedge-shaped cross section. The under-filled depositional phase is charac-teristic of deep marine environments in the wedge-top basins accompanied by active structures of thrust faults and mud diapers.     

弧陆碰撞背景下沉积物轴向与横向搬运转换*

板块俯冲碰撞拼合带是盆山相互作用最为强烈的地区,发育有弧前、弧间及弧后多种类型的盆地,沉积物的剥蚀搬运作用极为活跃。证据显示,沉积物搬运充填过程在构造—古地理控制型盆地中具有一定的演变规律,伴随盆地演化,沉积物轴向搬运与横向搬运呈此消彼长的互动关系。南海南北两侧均发育了大型板块俯冲拼合带及相关的沉积盆地,在盆地发育早期沉积物沿盆地长轴方向分别形成昆莺琼古河和巽他古河,以轴向搬运的方式分别把越南中部及马来半岛沉积物由西向东输送到南海,形成大型三角洲及前三角洲深水扇沉积,河流发育位置均在板块拼合转折地段。在盆地发育的成熟阶段,沉积物以横向搬运的方式进入盆地,与轴向搬运沉积物形成混合堆积。轴向搬运是洋陆碰撞拼合盆地中一种重要的沉积物搬运途径,主要受盆地形成时的构造古地理控制。     

弧陆碰撞背景下沉积物轴向与横向搬运转换*

板块俯冲碰撞拼合带是盆山相互作用最为强烈的地区,发育有弧前、弧间及弧后多种类型的盆地,沉积物的剥蚀搬运作用极为活跃。证据显示,沉积物搬运充填过程在构造—古地理控制型盆地中具有一定的演变规律,伴随盆地演化,沉积物轴向搬运与横向搬运呈此消彼长的互动关系。南海南北两侧均发育了大型板块俯冲拼合带及相关的沉积盆地,在盆地发育早期沉积物沿盆地长轴方向分别形成昆莺琼古河和巽他古河,以轴向搬运的方式分别把越南中部及马来半岛沉积物由西向东输送到南海,形成大型三角洲及前三角洲深水扇沉积,河流发育位置均在板块拼合转折地段。在盆地发育的成熟阶段,沉积物以横向搬运的方式进入盆地,与轴向搬运沉积物形成混合堆积。轴向搬运是洋陆碰撞拼合盆地中一种重要的沉积物搬运途径,主要受盆地形成时的构造古地理控制。     

龙门山前陆盆地底部不整合面: 被动大陆边缘到前陆盆地的转换

晚三叠世龙门山前陆盆地是在扬子板块西缘被动大陆边缘的基础上由印支造山运动而形成的,盆地中地层充填厚度巨大,包括晚三叠世卡尼期至瑞提期的马鞍塘组、小塘子组和须家河组,持续时间达20Myr,显示为1个以不整合面为界的构造层序。位于晚三叠世龙门山前陆盆地构造层序与下伏古生代-中三叠世被动大陆边缘构造层序之间的不整合面属于龙门山前陆盆地的底部不整合面,标志了扬子板块西缘从被动大陆边缘盆地到前陆盆地的转换。该底部不整合面位于晚三叠世马鞍塘组与中三叠世雷口坡组之间,显示为平行不整合面或角度不整合面,在接触面上发育冲蚀坑、古喀斯特溶沟、溶洞、溶岩角砾、古风化壳的褐铁矿、黏土层及石英、燧石细砾岩等底砾岩。该不整合面向南东方向不断地切削下伏地层,且均发育岩溶风化面,上覆的晚三叠世地层沿不整合面向南东超覆,显示了从整合面到不整合面的变化过程,并随着逆冲楔的推进向南东方向迁移,其超覆线、侵蚀带和相带的走向线与龙门山冲断带的走向大致平行。底部不整合面显示为典型的前陆挠曲不整合面,标志着龙门山前陆盆地的形成和扬子板块西缘挠曲下降和淹没过程,底部为古喀斯特作用面,下部为碳酸盐缓坡和海绵礁建造,上部为进积过程中形成的三角洲沉积物,具有向上变粗的垂向结构,表明底部不整合面和前缘隆起的抬升是扬子板块西缘构造负载的挠曲变形的产物,显示了在卡尼期松潘-甘孜残留洋盆的迅速闭合和逆冲构造负载向扬子板块的推进过程。本次在对晚三叠世龙门山前陆盆地底部不整合面的风化壳、残留厚度、地层缺失、剥蚀厚度、地层超覆等研究的基础上,计算了底部不整合面迁移速率、前缘隆起迁移速率、地层上超速率和前缘隆起的剥蚀速率,并与逆冲楔推进速率进行了对比,结果表明,底部不整合面迁移速率、前缘隆起的迁移速率、地层上超速率均介于3~18mm·a^-1之间,其与逆冲楔推进速率(5~15mm·a^-1)相似,因此,可用底部不整合面迁移速率、前缘隆起的迁移速率和地层上超速率代表逆冲楔推进速率。但是前缘隆起的剥蚀速率很小,介于0.02~0.08mm·a^-1之间,仅为逆冲楔推进速率的1/100。     

前陆盆地构造-热演化:以龙门山前陆盆地为例

前陆盆地油气资源丰富但构造变形十分复杂,使得前陆盆地构造-热演化模拟面临挑战。前陆盆地演化过程中构造与热的耦合体现在多个层面:岩石圈热演化对岩石圈强度时空分布及其挠曲的影响;逆冲推覆作用的浅部温度效应;快速沉积作用对盆地温度场的影响等。首先,前陆盆地形成时的岩石圈热背景及其造成的岩石圈强度空间变化对盆地后期的演化具有重要影响。同时早期热事件的热扰动也会叠加在前陆盆地的构造-热演化过程中,并不断衰减,影响岩石圈的流变结构,从而带来一系列的影响。热与构造演化相耦合在前陆盆地定量模拟中非常重要。其次,还需特别关注岩石圈深部过程与近地表构造过程的耦合。造山带逆冲推覆、抬升和剥蚀是与前陆盆地形成相关的重要构造活动,这种运动引起的热对流对造山带的热结构、前陆逆冲带以及前渊地区的温度场的分布有着重要影响。最后,前陆盆地形成演化过程中的快速沉积作用对盆地温度场和地表热流产生强烈的压制作用,对前陆盆地浅部热演化的影响不容忽视。因此,在浅部热演化(包括造山带逆冲推覆、快速沉积压实等)与盆地下伏岩石圈挠曲、深部热演化的联合作用下,使得前陆盆地构造-热演化颇为复杂,二者的耦合使得前陆盆地构造-热演化模拟颇具挑战。     

The South Westland Basin: seismic stratigraphy, basin geometry and evolution of a foreland basin within the Southern Alps collision zone, New Zealand

This paper develops further the case for a foreland basin origin of South Westland Basin, located adjacent to the Southern Alps mountain belt. Geohistory analyses show Middle Miocene initiation of subsidence in the basin, with marked increases at 5–6 Ma. Five seismic reflection horizons, including basement, Middle Miocene (top Awarua Limestone), top Miocene, mid-Pliocene (PPB) and mid-Pleistocene (PPA) have been mapped through the grid of seismic data. A series of five back-stripped structure contour maps taken together with five isopach maps show that prior to the Middle Miocene, subsidence and sedimentation occurred mainly along the rifted continental margin of the Challenger Plateau facing the Tasman Sea; subsequently it shifted to a foredeep trending parallel to the Southern Alps and located northwest of them. Through the Late Miocene–Recent this depocentre has progressively widened, and the loci of thickest sediment accumulation have moved northwestward, most prominently during the Late Pliocene and Pleistocene with the progradation of a shelf–slope complex. At the northern end of the basin the shelf–slope break is currently located over the forebulge, which appears not to have migrated significantly, probably because the mountain belt is not advancing significantly northwestwards. Modelling of the lithospheric flexure of the basement surface normal to the trend of the basin establishes values of 3.1 to 9.8×10²⁰ N m for the flexural rigidity of the Australia Plate. This is at the very low end of rigidities for plates, and 1–2 orders of magnitude less than for the Australia Plate beneath the Taranaki Basin. Maps of tectonic subsidence where the influence of sediment loading is removed also clearly identify the source of the loading as lying within or beneath the mountain belt. The basin fill shows a stratigraphic architecture typical of underfilled ancient peripheral foreland basins. This comprises transgressive (basal unconformity, thin limestone, slope-depth mudstone, flysch sequence) and regressive (prograding shelf–slope complex followed by molasse deposits) components. In addition the inner margin of the basin has been inverted as a result of becoming involved in the mountain building, as revealed earlier by fission track thermochronological data. The timing and degree of inversion fits well with the geometrical and stratigraphic development of the basin. That the inversion zone and the coastal plain underlain by molasse deposits are narrow, and most of the basin is beneath the sea, highlights this as an underfilled active foreland basin. The basin is geodynamically part of the Southern Alps collision zone.