Long-term fluvial archives in Hungary: response of the Danube and Tisza rivers to tectonic movements and climatic changes during the Quaternary: a review and new synthesis

The paper discusses the Quaternary evolution of the Danube and Tisza rivers and their main tributaries in the context of evolution of the entire Pannonian Basin, which is Europe's largest intramontane basin, within the Alp–Carpathian orogen. The palaeo-drainage reconstruction of the Pannonian Basin for the pre-Quaternary period is outlined in connection with the gradual regression of Lake Pannon since the Late Miocene. Deltas of rivers that entered the basin from the northwest and northeast were gradually transformed into extended alluvial plains; thus, the earliest possible ancestor of the Danube coming southeastwards from the Alps could be as old as Late Miocene. By the Pliocene the whole Lake Pannon was infilled. The former extensional basin formation was replaced by a compresional stress field, which resulted in an uplift of the marginal flanks and late-stage subsidence anomalies. The increasing relief led to the formation of the Quaternary drainage pattern. The actively subsiding young basins were filled by fluvial sediments, transported by the Danube and Tisza river systems from the uplifting mountains. Between the subsiding regions of the Little and Great Plains, the Danube has formed an antecedent valley with terrace staircases between the uplifting sections of the Transdanubian Range and the North Midmountains. The formation of the terraces is attributed to periodic climate changes during the Pleistocene combined with differences in the uplift rate. The paper gives a complex overview of the classical chronology of the six terraces based on various data sources: mostly dating of loess/paleosol sequences, travertines, aeolian sand, and tephra strata overlying the fluvial sediments, complemented by scattered vertebrate faunal data and archaeological evidence directly from the terrace sediments.The Quaternary drainage pattern evolution of the Great Plain, with a strong tectonic control, is discussed in detail. Rivers originating from the uplifting marginal areas were drawn towards the subsiding depressions which served as local base level. Changes in subsidence rates in space and time throughout the Quaternary resulted in the evolution of a complex drainage pattern. A special emphasis is placed on the Late Pleistocene–Holocene development of the Middle–Tisza region and the Körös basin, where the Berettyó–Körös Rivers form an eastern tributary system of the Tisza River. A comparative evaluation of these two areas is especially relevant, as they provide insights into large-scale Late Pleistocene avulsion of the Tisza River. OSL dating, complemented with inferred transport directions determined from heavy mineral analysis of fluvial sediments in the Körös basin, has revealed an ancient large meandering river system that can be identified with the palaeo-Tisza, which was flowing along a tectonically controlled depression during the Late Pleniglacial. Successions in the Middle Tisza region have allowed differentiation between the older channels of the palaeo-Bodrog River and the Sajó–Hernád alluvial fan and the younger meander belts of the new course of the Tisza. In the Tisza system, changes in river style (braided to various scales of meandering) show correspondence to millennial-scale climate changes of the last 25 ka, while in the Körös basin the effects of tectonics are overprinted onto the regional climatic signals.     

Middle to late Miocene sequence stratigraphy of the Transylvanian Basin (Romania)

The history of Middle to Late Miocene evolution of the Transylvanian Basin was determined by the bordering Carpathian orogen evolution, the tectonic events being well recorded by the sedimentary history. The basin evolved in a back-arc setting, under a regional, compressional stress field. The major tectonic events produced during the Late Sarmatian and Post-Pannonian were related to the reactivation of the pre-Badenian fault systems. The Transylvanian Basin got uplifted after the Late Pannonian (? during the Pliocene), and at least 500 m of sedimentary cover was eroded.

Based on seismic and well-log interpretation, core and outcrop sedimentology, and microfauna, eight sequences were defined. The early Middle Miocene sequences are roughly synchronous to five 3rd order global sea-level cycles. Most of the recognized sequence boundaries are enhanced by regional tectonic events. The sedimentary evolution was also strongly influenced by salt-tectonics, active starting with the Late Sarmatian.

Two sequences were identified in the Lower Badenian deposits. The third sequence (late Early Badenian to early Mid Badenian) preserves information about deeper shelf settings. The lowstand of the following sequence was responsible for the deposition of the salt formation (late Mid Badenian), an important lithostratigraphic marker in the sedimentary record of the basin. In general, the Upper Badenian deposits (parts of the 4th and 5th sequences) belong to deep marine submarine fan systems. The Sarmatian (partially 5th, 6th and partially 7th sequences) was characterized by diverse salinity conditions, stretching from brackish to hypersaline, and by high tectonic instability, which induced several significant relative sea-level falls. During that time, deltaic (north) and fandeltaic (east) systems fed submarine fans, stacked between salt-related submarine heights (“channeled” deep-marine depocenters). Most of the Pannonian deposits (partially 7th and 8th sequences) belong to submarine fan systems, but shallower facies were also found in the western and eastern part of the basin.     

珠江三角洲西缘晚第四纪沉积演化和最大海侵古岸线的重建

第四纪以来,受全球气候和海平面变化影响,海岸带地区发生了一系列强烈的海陆相互作用和海侵—海退等地质事件,包含了丰富的沉积环境演化和海平面变化等信息.选用珠江三角洲西缘台山地区的30个地质钻孔,通过14C、光释光、地球化学特征、底栖有孔虫、磁化率数据,建立了晚更新世以来的地层框架,重建了最大海侵古岸线的位置.研究结果表明...     

Tectonic,sea-level,and climatic controls on Late Paleozoic sedimentation in the western basins of Argentina

Tectonic activity, sea-level changes, and the climate controlled sedimentation in Late Paleozoic basins of western Argentina. The role of each factor is investigated from the geologic record of the Río Blanco and Paganzo basins using three hierarchical orders of stratigraphic bounding surfaces. First-order surfaces correspond to regional unconformities, second-order ones to local unconformities with a lesser regional extent, and third-order surfaces represent locally extended sedimentary truncation. Using this methodology, the Carboniferous–Permian record of the Paganzo and Río Blanco basins may be divided into two megasequences, four sequences, and 12 stratigraphic sections. Megasequences are bounded by regional unconformities that result from tectonic events important enough to cause regional paleogeographic changes. Sequences are limited by minor regional extension surfaces related to local tectonic movements or significant sea-level falls. Finally, stratigraphic sections correspond to extended sedimentary truncations produced by transgressive events or major climatic changes. Sequence I is mainly composed of marine deposits divided into basal infill of the basin (Section 1) and Tournaisian–Visean transgressive deposits (Section 2). Sequence II is bounded by a sharp erosional surface and begins with coarse conglomerates (Section 3), followed by fluvial and shallow marine sedimentary rocks (Section 4) that pass upward into shales and diamictites (Section 5). The base of Sequence III is marked by an extended unconformity covered by Early Pennsylvanian glacial sedimentary rocks (Section 6) that represent the most important glacial event along the western margin of Gondwana. Postglacial deposits (Section 7) occur in the two basins and comprise both glaciolacustrine (eastern region) and transgressive marine (central and western regions) deposits. By the Moscovian–Kasimovian, fluvial sandstones and conglomerates were deposited in most of the Paganzo Basin (Section 8), while localized volcanic activity took place in the Río Blanco Basin. Near the end of the Carboniferous, an important transgression is recorded in the major part of the Río Blanco Basin (Section 9), reaching the westernmost portion area of the Paganzo Basin. Finally, Sequence IV shows important differences between the Paganzo and Río Blanco basins; fluvial red beds (Section 10), eolian sandstones (Section 11), and low-energy fluvial deposits (Section 12) prevailed in the Paganzo Basin whereas volcaniclastic sedimentation and volcanism dominated in the Río Blanco Basin. Thus, tectonic events, sea-level changes and climate exerted a strong and complex control on the evolution of the Río Blanco and Paganzo basins. The interaction of these allocyclic controls produced not only characteristic facies association patterns but also different kinds of stratigraphic bounding surfaces.     

Tectonic, sea-level, and climatic controls on Late Paleozoic sedimentation in the western basins of Argentina

Tectonic activity, sea-level changes, and the climate controlled sedimentation in Late Paleozoic basins of western Argentina. The role of each factor is investigated from the geologic record of the Río Blanco and Paganzo basins using three hierarchical orders of stratigraphic bounding surfaces. First-order surfaces correspond to regional unconformities, second-order ones to local unconformities with a lesser regional extent, and third-order surfaces represent locally extended sedimentary truncation. Using this methodology, the Carboniferous–Permian record of the Paganzo and Río Blanco basins may be divided into two megasequences, four sequences, and 12 stratigraphic sections. Megasequences are bounded by regional unconformities that result from tectonic events important enough to cause regional paleogeographic changes. Sequences are limited by minor regional extension surfaces related to local tectonic movements or significant sea-level falls. Finally, stratigraphic sections correspond to extended sedimentary truncations produced by transgressive events or major climatic changes. Sequence I is mainly composed of marine deposits divided into basal infill of the basin (Section 1) and Tournaisian–Visean transgressive deposits (Section 2). Sequence II is bounded by a sharp erosional surface and begins with coarse conglomerates (Section 3), followed by fluvial and shallow marine sedimentary rocks (Section 4) that pass upward into shales and diamictites (Section 5). The base of Sequence III is marked by an extended unconformity covered by Early Pennsylvanian glacial sedimentary rocks (Section 6) that represent the most important glacial event along the western margin of Gondwana. Postglacial deposits (Section 7) occur in the two basins and comprise both glaciolacustrine (eastern region) and transgressive marine (central and western regions) deposits. By the Moscovian–Kasimovian, fluvial sandstones and conglomerates were deposited in most of the Paganzo Basin (Section 8), while localized volcanic activity took place in the Río Blanco Basin. Near the end of the Carboniferous, an important transgression is recorded in the major part of the Río Blanco Basin (Section 9), reaching the westernmost portion area of the Paganzo Basin. Finally, Sequence IV shows important differences between the Paganzo and Río Blanco basins; fluvial red beds (Section 10), eolian sandstones (Section 11), and low-energy fluvial deposits (Section 12) prevailed in the Paganzo Basin whereas volcaniclastic sedimentation and volcanism dominated in the Río Blanco Basin. Thus, tectonic events, sea-level changes and climate exerted a strong and complex control on the evolution of the Río Blanco and Paganzo basins. The interaction of these allocyclic controls produced not only characteristic facies association patterns but also different kinds of stratigraphic bounding surfaces.     

Drainage evolution in south and east England during the Pleistocene

Two major river systems operated in southern and eastern England throughout the Pleistocene: the river Thames and the Solent river. Both rivers are axial streams of comparable size draining major basinal structures comprising similar Tertiary and Mesozoic rocks. Although the modem Thames flows broadly W-E in the London Basin, upstream of Reading it flows from the north to drain the south Midlands. It was diverted to its present course through London by glaciation in the Anglian (Elsterian) before which it flowed across East Anglia into the southem North Sea. The Solent river no longer exists since most of its course was drowned by eustatic sea-level rise during the Flandrian Stage (Holocene). Previously, it flowed eastwards across SE Dorset and S Hampshire as an extension of the modem river Frome in the Hampshire Basin. During periods of low sea-level (cold stages) it was a tributary of the 'Channel River'. Fluvial aggradations provide evidence of the former courses of these substantial rivers and their tributaries. The facies and sedimentary structures indicate that the bulk of the deposits in both systems accumulated in braided river environments under periglacial climates. Fossiliferous sediments provide biostratigraphical frameworks. During temperate periods the rivers adopted singlethread courses. Evolution of both rivers reflect their responses to climatic change, local geological structure and long-term tectonic activity. Both rivers are undoubtedly of considerable antiquity, their records potentially extend from the Early Pleistocene or Late Pliocene, but they may have originated in the early Tertiary.     

第四纪洞庭盆地安乡凹陷及西缘构造-沉积特征与环境演化

通过地表观察和钻孔资料,对洞庭盆地安乡凹陷及其西缘第四纪构造沉积特征和环境演化进行了研究,为江汉—洞庭盆地第四纪地质研究补充了新的资料。凹陷总体呈南北向,周边为正断裂。凹陷内第四系厚一般为100-220 m,最厚达300 m,自下而上依次为早更新世华田组、汨罗组,中更新世洞庭湖组,晚更新世坡头组和全新世湖冲积。第四系以砾石层、砂层为主,次为（含）粉砂质黏土、黏土,岩性、岩相横向变化大。安乡凹陷西缘（即太阳山隆起东缘）,呈自西向东缓倾的丘岗地貌。区内主要发育中更新世白沙井组,其中南部下部以砂、砾石层为主,上部为黏土;北部以粉砂质黏土沉积为主,下部可发育砂层。根据地貌、沉积及控凹断裂特征,重塑安乡凹陷及其西缘第四纪构造活动与环境演化过程：早更新世—中更新世早期,凹陷西边的北北东向周家店断裂伸展活动,安乡凹陷不均匀沉降,总体具河流和过流性湖泊环境并接受沅水沉积;同期凹陷西缘构造抬升,处于剥蚀的山地环境。中更新世中期断陷活动向西扩展,凹陷区为过流性湖泊环境;凹陷西缘地区转为河流（南部）和湖泊（北部）环境并接受沉积。中更新世晚期安乡凹陷及其西缘整体抬升并遭受剥蚀,凹陷西缘同时具有自西向东的掀斜。晚更新世安乡凹陷拗陷沉降,具河流和湖泊环境;同期凹陷西缘遭受剥蚀。晚更新世末受区域海平面下降影响,安乡凹陷遭受剥蚀。全新世安乡凹陷拗陷沉降,具泛滥平原之河流、湖泊环境。     

晚第四纪长江源区水系演化对断裂活动和气候变化的响应

河流沉积/侵蚀过程和水系演化对构造活动、气候变化和侵蚀基准面的响应过程与机制是流域地貌的重要科学问题。长江源地区河流受高寒气候和走滑断层引起的局部多种构造活动样式的影响, 是河流地貌过程对气候变化和构造活动响应的典型案例。文章通过野外考察、地貌指数(陡峭指数(k_sn)、Chi(χ)、Gilbert指数、河谷宽高比(Vf))的计算、沉积学和地形分析, 探讨了长江源水系演化对构造活动和气候变化的响应过程。通天河和澜沧江支流从上游相对年老的谷地(北西-南东向低k_sn值、高Vf值的宽谷)转变为下游相对年轻的谷地(南西-北东向高k_sn值、低Vf值的陡峭峡谷), 表明南西-北东向河流对北西-南东向河流的袭夺。通天河和澜沧江支流上游地区显示的高χ值、低起伏地形向下游方向快速转变为低χ值、高起伏地形, 也指示澜沧江和通天河向上游溯源侵蚀、袭夺分水岭地区原有老年期水系。局部分布的北西-南东向河谷(风口)、一系列间隔分布低洼地内河流沉积物和初步光释光年测年结果(13.3ka和>115ka)表明该地区在晚第四纪(可能在暖期)发育一条南东流向的古河流。随后断层走滑运动导致的局部构造抬升将河流分割成相互独立的内流湖。后期通天河和澜沧江干流(局部侵蚀基准面)侵蚀下降导致南西-北东向支流溯源侵蚀, 袭夺内流湖; 水系由树枝状演化为倒勾状。区域构造活动和局部侵蚀基准面变化是控制该地区水系演化的主要因素。晚第四纪气候变化引起河流堆积/侵蚀过程的改变也对水系的连通/中断有一定的影响, 后期需要进一步的研究。

     

Tectonics versus eustatic control on supersequences of the Zagros Mountains of Iran

At least 12 km of strata ranging in age from the latest Precambrian to the Recent are exposed in the Zagros Mountains of Iran. This sedimentary cover is characterized by distinct stratal packages separated by major unconformities forming twelve supersequences. They are informally named as: (1) Late Precambrian – Cambrian Hakhamanesh Supersequence, (2) Ordovician Kourosh Supersequence, (3) Silurian Camboojiyeh Supersequence, (4) Devonian Darioush Supersequence, (5) Mississippian – Pennsylvanian Khashayar Supersequence, (6) Permian – Triassic Ashk Supersequence, (7) Jurassic Farhad Supersequence, (8) Early Cretaceous Mehrdad Supersequence, (9) Late Cretaceous Ardavan Supersequence, (10) Paleocene – Oligocene Sassan Supersequence, (11) Oligocene – Miocene Ardeshir Supersequence, and (12) Miocene – Pleistocene Shapour Supersequence. These supersequences and their correlatives in neighboring areas have been used to infer tectonic events. The dominant interpretation has been that local or regional epeirogenic movements were responsible for the formation of these supersequences. Unconformities are considered as indications that epeirogenic movements associated with tectonic events affected the area. The present investigation provides an alternative to the established view of the Phanerozoic supersequences of the Zagros Mountains.

A good correlation exists between the lithofacies of supersequences in the Zagros Mountains and the second-order eustatic sea-level changes. Deposition of deep-water, marine shales occurred during periods of eustatic sea-level rise. Platform-wide unconformities coincided with eustatic sea-level lows. In fact, supersequences of the Zagros Mountains are nearly identical to those described from the North American Craton and the Russian Platform suggesting that these stratal packages are global. These observations suggest that supersequences of the Zagros Mountains formed by second order eustatic sea-level changes and not by local or regional epeirogenic movements.

Although tectonic events did not produce supersequences of the Zagros Mountains, they influenced regional lithofacies patterns through the formation of intrashelf depressions such as the Hormoz Salt Basin during the Precambrian and the Dezful Embayment and the Lorestan Basin during the Mesozoic. Tectonic events also affected sedimentation during the Tertiary collision of Arabia and the Central Iran microplate through uplift, erosion, and the formation of the Zagros Foreland Basin. The results of this investigation necessitate a re-evaluation of the role and the significance of pre-Tertiary tectonic events commonly used to interpret the geological evolution of the Zagros Mountains.     

Depositional facies,environments and sequence stratigraphic interpretation of the Middle Triassic–Lower Cretaceous (pre-Late Albian) succession in Arif El-Naga anticline,northeast Sinai,Egypt

The Middle Triassic–Lower Cretaceous (pre-Late Albian) succession of Arif El-Naga anticline comprises various distinctive facies and environments that are connected with eustatic relative sea-level changes, local/regional tectonism, variable sediment influx and base-level changes. It displays six unconformity-bounded depositional sequences. The Triassic deposits are divided into a lower clastic facies (early Middle Triassic sequence) and an upper carbonate unit (late Middle- and latest Middle/early Late Triassic sequences). The early Middle Triassic sequence consists of sandstone with shale/mudstone interbeds that formed under variable regimes, ranging from braided fluvial, lower shoreface to beach foreshore. The marine part of this sequence marks retrogradational and progradational parasequences of transgressive- and highstand systems tract deposits respectively. Deposition has taken place under warm semi-arid climate and a steady supply of clastics. The late Middle- and latest Middle/early Late Triassic sequences are carbonate facies developed on an extensive shallow marine shelf under dry-warm climate. The late Middle Triassic sequence includes retrogradational shallow subtidal oyster rudstone and progradational lower intertidal lime-mudstone parasequences that define the transgressive- and highstand systems tracts respectively. It terminates with upper intertidal oncolitic packstone with bored upper surface. The next latest Middle/early Late Triassic sequence is marked by lime-mudstone, packstone/grainstone and algal stromatolitic bindstone with minor shale/mudstone. These lower intertidal/shallow subtidal deposits of a transgressive-systems tract are followed upward by progradational highstand lower intertidal lime-mudstone deposits. The overlying Jurassic deposits encompass two different sequences. The Lower Jurassic sequence is made up of intercalating lower intertidal lime-mudstone and wave-dominated beach foreshore sandstone which formed during a short period of rising sea-level with a relative increase in clastic supply. The Middle-Upper Jurassic sequence is represented by cycles of cross-bedded sandstone topped with thin mudstone that accumulated by northerly flowing braided-streams accompanying regional uplift of the Arabo–Nubian shield. It is succeeded by another regressive fluvial sequence of Early Cretaceous age due to a major eustatic sea-level fall. The Lower Cretaceous sequence is dominated by sandy braided-river deposits with minor overbank fines and basal debris flow conglomerate.     

祁连山大通河河流阶地形成时代及地质意义

祁连山是研究青藏高原隆升与构造变形的关键部位,其中大通河河流阶地是祁连山地区早更新世以来构造隆升和气候变化的载体,厘定大通河河流阶地的形成时代及地质意义对于分析祁连山地区的区域构造和气候环境改变具有重要意义。通过ESR测年技术,并对大通河流域江仓区域的剖面样品实测,获取岩层形成时代数据,分别为(42±4) ka B.P.、(71±5) ka B.P.、(121±12) ka B.P.、(210±20) ka B.P.和(602±60) ka B.P.。根据测年结果,确认剖面为河流相沉积环境,形成时代对应中晚更新世酒泉砾岩和戈壁砾岩时期,表明大通河河流阶地在542~662 ka B.P.之前就已经形成,推测其可能是受到中新世白杨河组之后的盆山运动或早更新世祁连山的褶皱变形影响而形成的。利用测年数据计算抬升速率,从中更新世晚期到晚更新世中期,抬升速率加快,反映了大通河流域的构造运动和气候变化加强,祁连山江仓地区在此期间快速隆升,为青藏高原东北缘以面积和体积扩张的观点提供了新的依据。     

Causes and mechanisms of the modification of the fluvial drainage basins

The relationship between the tectonic structure of the Ai–Ufa interfluve (Southern Urals), its morphology, the recent deformations, and the distribution of clastic material in the fluvial basins were studied. Geological interpretations are suggested for the problematic local areas of the drainage basins, whose structure and evolution are distinct from the model scenarios. The sedimentary regime of the river valleys is controlled, first of all, by their configuration and orientation of the valley segments relative to the tectonic zones, as well as by the amount of clastic material that is delivered by tributaries, the climate history of the fluvial basin, and its recent tectonic activity.     

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.     

渤海南部莱州湾晚更新世以来沉积演化特征

晚更新世以来渤海南部莱州湾发生了3次重要海侵-海退事件及沉积演化过程,渤海南部多源河流三角洲对莱州湾沉积环境改变作用明显。本文选择莱州湾剖面进行沉积地层对比,结合调查资料和测试数据,初步建立莱州湾沉积地层格架,分析晚更新世以来莱州湾沉积演化过程。研究发现,渤海南部中小河流与黄河泥沙为莱州湾沉积物的共同物质来源,二者在不同阶段分别对莱州湾沉积演化起主导作用。提出本区沉积地层具有分期性、分段性和相关性规律。在124.6~72.0 ka B.P.,60.0~24.4 ka B.P.和10.2~4.0 ka B.P.出现过3次暖湿期,分别对应沧州海侵、献县海侵和黄骅海侵,主要发育滨浅海相沉积,向南退积为三角洲/潮坪—河流沉积;由陆向海,短源河流沉积贡献降低,黄河沉积贡献增加。在72.0~60.0 ka B.P.和24.4~10.2 ka B.P.出现2次冷干期,分别对应玉木早冰期和玉木晚冰期,河流相发育,三角洲进积。受海陆交互作用影响,晚更新世以来渤海南部莱州湾大致经历了浅海相—三角洲—潮坪—浅海相—三角洲—陆相的沉积演化。     

鄂尔多斯地块西南缘千河水系变迁与新构造运动

鄂尔多斯地块西南缘新构造运动活跃,其河流阶地发育过程和水系演化历史蕴藏了丰富的新构造运动信息。发育于鄂尔多斯西南缘的千河水系两岸不对称分布5级河流阶地,通过野外调查和钻探揭露,厘清了阶地结构和发育特征,利用电子自旋共振(ESR)测年、光释光(OSL)测年和黄土地层对比定年,分析了阶地形成的时代和下切速率,结合区域地质背景,探讨千河阶地发育和水系变迁的动力背景。研究结果表明,千河干流T5~T1阶地分别形成于1.176 Ma、0.766 Ma、0.504 Ma、0.131 Ma和0.04 Ma,各级阶地对应的下切速率分别为76.6 mm/ka、88.3 mm/ka、111.3 mm/ka、149.6 mm/ka和115 mm/ka。通过研究认为,早更新世—晚更新世中期,千河流域区构造运动逐渐加强,晚更新世晚期以后,构造运动逐渐趋缓。河流演化受断裂构造控制,但不同时期构造应力场对千河水系的影响有差别,使千河向不同方向迁移。构造应力场的变化受控于鄂尔多斯地块所处大地构造位置,很可能是青藏高原构造系和西太平洋构造系晚新生代以来在鄂尔多斯西南缘共同作用的结果。     

天水盆地晚新生代构造演化——对青藏高原北东向扩展的指示意义

天水盆地是一个位于青藏高原东北缘的晚新生代盆地,西秦岭北缘断裂穿盆而过。盆地内充填了较为完整的晚新生代地层,记录了该区晚新生代以来的构造变形历史,对研究青藏高原北东向扩展的构造响应具有重要意义。本文基于详细的野外构造变形分析与测量,结合已有的年代学与沉积学研究,初步提出天水盆地晚新生代以来构造变形序列与构造应力场,重建其晚新生代构造演化历史。详细研究表明,天水盆地晚新生代以来主要经历了3期构造演化:即中新世早-晚期NW-SE向构造伸展,沉积盆地发育,并伴随碱性超基性火山岩喷发和金刚石矿床形成;中新世晚期-早、中更新世NE-SW向挤压,盆地发生构造反转,其动力学背景可能源于晚新生代青藏高原的北东向扩展,指示高原物质扩散开始显著影响到西秦岭地区;晚更新世以来受近N-S向伸展作用控制,盆地发生向东有限挤出并伴随顺时针旋转,主要由于青藏高原向北东扩展过程中,区域构造挤压应力方向发生顺时针偏转所致。     

北天山山前安集海河阶地形成的时代及意义

北天山山前几条主要河流普遍发育河谷阶地。安集海河发育６～８级阶地,通过年代测定及区域对比,可得出安集海河阶地形成于中更新世晚期一晚更新世早期（约１２～１４万年左右）。第四纪以来构造活动及气候变化控制着河流下切和侧蚀作用的进行,安集海河阶地的形成和发育明显受第四纪晚期构造活动和气候变化等因素的影响。     

Late Quaternary valley-fill succession of the Lower Tagus Valley, Portugal

The Lower Tagus Valley in Portugal contains a well-developed valley-fill succession covering the complete Late Pleistocene and Holocene periods. As large-scale stratigraphic and chronologic frameworks of the Lower Tagus Valley are not yet available, this paper describes facies, facies distribution, and sedimentary architecture of the late Quaternary valley fill. Twenty four radiocarbon ages provide a detailed chronological framework. Local factors affected the nature and architecture of the incised valley-fill succession. The valley is confined by pre-Holocene deposits and is connected with a narrow continental shelf. This configuration facilitated deep incision, which prevented large-scale marine flooding and erosion. Consequently a thick lowstand systems tract has been preserved. The unusually thick lowstand systems tract was probably formed in a previously (30,000–20,000 cal BP) incised narrow valley, when relative sea-level fall was maximal. The lowstand deposits were preserved due to subsequent rapid early Holocene relative sea-level rise and transgression, when tidal and marine environments migrated inland (transgressive systems tract). A constant sea level in the middle to late Holocene, and continuous fluvial sediment supply, caused rapid bayhead delta progradation (highstand systems tract). This study shows that the late Quaternary evolution of the Lower Tagus Valley is determined by a narrow continental shelf and deep glacial incision, rapid post-glacial relative sea-level rise, a wave-protected setting, and large fluvial sediment supply.     

塔里木盆地上新世晚期—更新世早期伸展构造:喜马拉雅碰撞造山远程效应的一个构造间歇期

受控于印度-亚洲碰撞的远程效应,中亚地区的晚新生代挤压冲断构造异常发育,同时发育少量区域挤压构造背景下派生的局部伸展构造。以往的研究没有发现晚新生代区域性伸展构造。我们通过认真、系统的地震资料解释,在塔里木盆地发现一系列上新世晚期-更新世早期的正断层。这些正断层主要分布于塔里木盆地西部的阿瓦提坳陷、巴楚隆起、麦盖提斜坡以及塘古孜巴斯坳陷。正断层走向NW-SE和NE-SW,剖面上组合成堑-垒构造,仅塔里木盆地西北缘沿沙井子断裂带分布的上新世晚期-更新世早期正断层带组合成负花状构造,显示出张扭性断层带的特征。根据生长指数计算,正断层活动的起始时间是上新世晚期（ca.3 Ma）,持续演化至更新世早期（ca.2 Ma）,然后停止活动。这些正断层形成于一个弱的区域性伸展构造背景;这期正断层活动代表印度-亚洲碰撞远程效应下,中亚地区脉动挤压冲断过程中的一个构造间歇期。     

Basin formation during the post-collisional evolution of the Eastern Alps: the example of the Lavanttal Basin

The Miocene Lavanttal Basin formed in the Eastern Alps during extrusion of crustal blocks towards the east. In contrast to basins, which formed contemporaneously along the strike-slip faults of the Noric Depression and on top of the moving blocks (Styrian Basin), little is known about the Lavanttal Basin. In this paper geophysical, sedimentological, and structural data are used to study structure and evolution of the Lavanttal Basin. The eastern margin of the 2-km-deep basin is formed by the WNW trending Koralm Fault. The geometry of the gently dipping western basin flank shows that the present-day basin is only a remnant of a former significantly larger basin. Late Early (Karpatian) and early Middle Miocene (Badenian) pull-apart phases initiated basin formation and deposition of thick fluvial (Granitztal Beds), lacustrine, and marine (Mühldorf Fm.) sediments. The Mühldorf Fm. represents the Lower Badenian cycle TB2.4. Another flooding event caused brackish environments in late Middle Miocene (Early Sarmatian) time, whereas freshwater environments existed in Late Sarmatian time. The coal-bearing Sarmatian succession is subdivided into four fourth-order sequences. The number of sequences suggests that the effect of tectonic subsidence was overruled by sea-level fluctuations during Sarmatian time. Increased relief energy caused by Early Pannonian pull-apart activity initiated deposition of thick fluvial sediments. The present-day shape of the basin is a result of young (Plio-/Pleistocene) basin inversion. In contrast to the multi-stage Lavanttal Basin, basins along the Noric Depression show a single-stage history. Similarities between the Lavanttal and Styrian basins exist in Early Badenian and Early Sarmatian times.