Late Cenozoic uplift of western Turkey: Improved dating of the Kula Quaternary volcanic field and numerical modelling of the Gediz River terrace staircase   总被引：7，自引：3，他引：4  

Rob Westaway  Herv Guillou  Sema Yurtmen  Anthony Beck  David Bridgland  Tuncer Demir  Stphane Scaillet  George Rowbotham 《Global and Planetary Change》2006,51(3-4):131-171

A set of 13 new unspiked K–Ar dates has been obtained for the Quaternary basaltic volcanism in the Kula area of western Turkey, providing improved age control for the fluvial deposits of the Gediz River that underlie these basalt flows. This dating is able, for the first time, to resolve different ages for the oldest basalts, assigned to category β2, that cap the earliest Gediz deposits recognised in this area, at altitudes of 140 to 210 m above present river level. In particular, the β2 basalt capping the Sarnıç Plateau is dated to 1215 ± 16 ka (± 2σ), suggesting that the youngest underlying fluvial deposits, 185 m above present river level, are no younger than marine oxygen isotope stage (MIS) 38. In contrast, the β2 basalt capping the adjacent Burgaz Plateau is dated to 1014 ± 23 ka, suggesting that the youngest underlying fluvial deposits, 140 m above present river level, date from MIS 28. The staircase of 11 high Gediz terraces capping the latter plateau is thus dated to MIS 48-28, assuming they represent consecutive 40 ka Milankovitch cycles, although it is possible that as many as two cycles are missing from this sequence such that the highest terrace is correspondingly older. Basalt flows assigned to the β3 category, capping Gediz terraces 35 and 25 m above the present river level, have been dated to 236 ± 6 ka and 180 ± 5 ka, indicating incision rates of 0.15 mm a^− 1, similar to the time-averaged rates since the eruptions of the β2 basalts. The youngest basalts, assigned to category β4, are Late Holocene; our K–Ar results for them range from zero age to a maximum of 7 ± 2 ka.This fluvial incision is interpreted using numerical modelling as a consequence of uplift caused by a regional-scale increase in spatial average erosion rates to 0.1 mm a^− 1, starting at 3100 ka, caused by climate deterioration, since when a total of 410 m of uplift has occurred. Parameters deduced on this basis from the observed disposition of the Early Pleistocene Gediz terraces include the local effective viscosity of the lower crust, which is 2 × 10¹⁸ Pa s, the Moho temperature of 660 °C, and the depth of the base of the brittle upper crust, which is 13 km. The thin lithosphere in this area results in high heat flow, causing this relatively shallow base of the brittle upper crust and the associated relatively thick lower-crustal layer, situated between depths of 13 and 30 km. It estimated that around 900 ka, at the start of the 100 ka Milankovitch forcing, the spatial average erosion rate increased slightly, to 0.12 mm a^− 1; the associated relatively sluggish variations in uplift rates are as expected given the relatively thick lower-crustal layer.This modelling indicates that the growth of topography since the Pliocene in this study region has not involved a steady state. The landscape was significantly perturbed by the Middle Pliocene increase in erosion rates, and has subsequently adjusted towards—but not reached—a new steady state consistent with these increased erosion rates. It would not be possible to constrain what has been occurring from the Middle to Late Pleistocene or even the Early Pleistocene uplift response alone; information regarding the starting conditions is also essential, this being available in this region from the older geological record of stacked fluvial and lacustrine deposition. This result has major implications for the rigorous modelling of uplift histories in regions of rapid erosion, where preservation of information to constrain the starting conditions is unlikely.  相似文献   

黔中隆起金沙地区中新生代隆升剥蚀的裂变径迹分析     

罗开平  刘光祥  王津义 《海相油气地质》2009,14(1)

对贵州金沙地区取样进行了裂变径迹热史模拟,结合地质分析再现了黔中隆起的沉降和隆升剥蚀作用过程。该地区经历了180～70Ma时期的沉降埋藏增温和70Ma之后的剥蚀冷却降温两大阶段。沉降阶段的增温速率为0.909℃/Ma,对应的T3—K的沉积厚度约为4550m。冷却降温曲线分为三段:70～15Ma,样品温度从120℃降低到60℃,冷却速率为1.09℃/Ma;15～5Ma为一个"平台"期,样品温度维持在60℃左右;5Ma至今,样品温度从60℃快速冷却至20℃,冷却速率达8℃/Ma,这与喜马拉雅期云贵高原的整体隆升和晚期快速崛起相对应。计算表明,晚白垩世以来的隆升剥蚀量达2800m左右。  相似文献   

The Tjellefonna fault system of Western Norway: Linking late-Caledonian extension, post-Caledonian normal faulting, and Tertiary rock column uplift with the landslide-generated tsunami event of 1756     

T.F. Redfield  P.T. Osmundsen   《Tectonophysics》2009,474(1-2):106

On February 22, 1756, approximately 15.7 million cubic meters of bedrock were catastrophically released as a giant rockslide into the Langfjorden. Subsequently, three  40 meter high tsunami waves overwhelmed the village of Tjelle and several other local communities. Inherited structures had isolated a compartment in the hanging wall damage zone of the fjord-dwelling Tjellefonna fault. Because the region is seismically active in oblique-normal mode, and in accordance with scant historical sources, we speculate that an earthquake on a nearby fault may have caused the already-weakened Tjelle hillside to fail.From interpretation of structural, geomorphic, and thermo-chronological data we suggest that today's escarpment topography of Møre og Trøndelag is controlled to a first order by post-rift reactivation of faults parallel to the Mesozoic passive margin. In turn, a number of these faults reactivated Late Caledonian or early post-Caledonian fabrics.Normal-sense reactivation of inherited structures along much of coastal Norway suggests that a structural link exists between the processes that destroy today's mountains and those that created them. The Paleozoic Møre–Trøndelag Fault Complex was reactivated as a normal fault during the Mesozoic and, probably, throughout the Cenozoic until the present day. Its NE–SW trending strands crop out between the coast and the base of a c. 1.7 km high NW-facing topographic ‘Great Escarpment.’ Well-preserved kinematic indicators and multiple generations of fault products are exposed along the Tjellefonna fault, a well-defined structural and topographic lineament parallel to both the Langfjorden and the Great Escarpment. The slope instability that was formerly present at Tjelle, and additional instabilities currently present throughout the region, may be viewed as the direct product of past and ongoing development of tectonic topography in Møre og Trøndelag county. In the Langfjorden region in particular, structural geometry suggests additional unreleased rock compartments may be isolated and under normal fault control.Although post-glacial rebound and topographically-derived horizontal spreading stresses might in part help drive present-day oblique normal seismicity, the normal-fault-controlled escarpments of Norway were at least partly erected in pre-glacial times. Cretaceous to Early Tertiary post-rift subsidence was interrupted by normal faulting at the innermost portion of the passive margin, imposing a strong tectonic empreinte on the developing landscape.  相似文献   

Uplift and active tectonics of southern Albania inferred from incision of alluvial terraces   总被引：2，自引：0，他引：2  

J. Carcaillet  J.L. Mugnier  R. Koi  F. Jouanne 《Quaternary Research》2009,71(3):465-476

In Albania, the Osum and Vjoje rivers cross the active graben system and the active frontal thrust system of the Albanides. The effects of climatic and geodynamic forcing on the development of these two rivers were investigated by the means of field mapping, topographic surveying and absolute exposure-age dating. We established the chronology of terraces abandonment from the compilation of new dating (¹⁴C and in situ produced ¹⁰Be) and previously published data. We identified nine fluvial terraces units developed since Marine Isotope Stage 6 up to historic times. From this reconstituted history, we quantified the vertical uplift on a time scale shorter than the glacial climatic cycle. Regional bulging produces an overall increase of the incision rate from the west to the east that reaches a maximum value of 2.8 m/ka in the hinterland. Local pulses of incision are generated by activation of normal faults. The most active faults have a SW–NE trend and a vertical slip rate ranging from 1.8 to 2.2 m/ka. This study outlines the geodynamic control in the development of rivers flowing through the Albanides on the scale of 10³–10⁵ka.  相似文献   

埕宁隆起北坡新近系层序地层格架与层序主控因素分析     

陈蓉  李勇  丘东洲  袁淑琴  刘子藏 《地层学杂志》2010,34(2)

根据构造演化及沉积响应特征,利用钻井取芯、岩屑录井、测井资料以及高分辨率地震资料,将埕宁隆起北坡新近系划分为1个超长期、7个长期旋回层序。通过精确的层序地层划分及井震对比,建立了研究区新近系的等时层序地层格架。在此基础上,对层序发育的主控因素进行了探讨,认为构造沉降、全球海平面变化、气候变化、地形因素及河流类型是埕宁隆起北坡新近系层序形成与发展的主要控制因素。高精度层序地层划分及层序地层格架的建立对埕宁隆起北坡新近系岩性油气藏的勘探开发具有重要指导意义。  相似文献   

源外地区油气成藏特征、主控因素及地质评价——以准噶尔盆地西缘车排子凸起春光油田为例   总被引：5，自引：1，他引：4  

沈扬  贾东  宋国奇  丁咸宝  李茂榕 《地质论评》2010,56(1):51-59

在油气近源富集的大背景下,仍有部分油气在远离烃源区被发现。对于这部分油气藏如何进行合理的解释?其与烃源区内油气成藏条件和主控因素有何不同?本文根据油藏(圈闭)—烃源的空间配置和成藏联系,将其分为源内、源边和源外三种类型。与源内相比,源外有其独特的地质条件和成藏机制。源外成藏虽较源内苛刻,但在一定的条件仍然可以局部富集形成大油气田。以准噶尔盆地西缘车排子凸起春光油田为实例进行典型解剖,提出生烃凹陷丰富的烃源、高效的输导体系和良好的时空配置关系是其得以源外成藏的主要控制因素。源外地区作为一个新的勘探领域,具备很大的拓展潜力和空间。在油气勘探中,应注意源外成藏的可能性,并采取针对性的以输导条件为核心的研究思路开展源外地区的油气勘探评价。  相似文献   

胶东西北部金矿剥蚀程度及找矿潜力和方向——来自磷灰石裂变径迹热年代学的证据   总被引：5，自引：2，他引：3  

柳振江  王建平  郑德文  刘家军  刘俊  付超 《岩石学报》2010,26(12):3597-3611

矿床形成后会经历不同形式的变化,区域隆升与剥蚀是影响矿床变化保存最为关键的因素之一。构造-热年代学是目前广泛运用于研究区域隆升剥蚀的一种重要手段,本文以我国最大金矿集中区———胶东西北部金矿及赋矿围岩玲珑花岗岩为研究对象,尝试将构造-热年代学引用到矿床成矿后变化与保存研究。通过磷灰石裂变径迹热年代学测试获得玲珑花岗岩距今110Ma以来的隆升演化历史,结果显示岩体剥蚀速率很小,平均0.0303±0.0044mm.a-1,自金矿形成后区域热-构造运动趋于平静,这对矿床的保存非常有利。胶东金矿成矿深度范围集中于4~10km,根据剥蚀速度计算玲珑花岗岩剥蚀量仅为2.0~4.2km,远未达到金矿最大成矿深度。当前本区金矿勘探和开采深度普遍小于2km,深部金矿找矿潜力良好。  相似文献   

穿越东沙隆起和潮汕坳陷的OBS广角地震剖面   总被引：15，自引：9，他引：6       下载免费PDF全文

卫小冬  阮爱国  赵明辉  丘学林  李家彪  朱俊江  吴振利  丁巍伟 《地球物理学报》2011,54(12):3325-3335

为了探明南海中北部陆缘深部地壳结构,使用2D射线追踪正演和反演方法,拟合了一条南海中北部陆缘的OBS广角地震剖面(OBS2006-3).该剖面穿越东沙隆起和潮汕坳陷,长319 km,NNW-SSE走向,共投放海底地震仪14台.速度结构模型表明:潮汕坳陷存在巨厚的中生代沉积,最大厚度达到8 km,速度从顶部的4.4 km...  相似文献   

Seismic stratigraphy and structural analysis of the northern East China Sea Shelf Basin interpreted from multi-channel seismic reflection data and cross-section restoration   总被引：1，自引：0，他引：1  

Deniz Cukur  Senay HorozalDae C. Kim  Hyun C. Han 《Marine and Petroleum Geology》2011,28(5):1003-1022

Analysis of multi-channel seismic data from the northern East China Sea Shelf Basin (ECSSB) reveals three sub-basins (Socotra, Domi, and Jeju basins), separated by structural highs (Hupijiao Rise) and faulted basement blocks. These sub-basins show a typical rift-basin development: faulted basement and syn-rift and post-rift sedimentation separated by unconformities. Four regional unconformities, including the top of acoustic basement, have been identified and mapped from multi-channel seismic data. Faults in the acoustic basement are generally trending NE, parallel to the regional structural trend of the area. The depths of the acoustic basement range from less than 1000 m in the northwestern part of the Domi Basin to more than 4500 m in the Socotra Basin and 5500 m in the Jeju Basin. The total sediment thicknesses range from less than 500 m to about 1500 m in the northwest where the acoustic basement is shallow and reach about more than 5500 m in the south.Interpretation of seismic reflection data and reconstruction of three depth-converted seismic profiles reveal that the northern ECSSB experienced two phases of rifting, followed by regional subsidence. The initial rifting in the Late Cretaceous was driven by the NW-SE crustal stretching of the Eurasian Plate, caused by the subduction of the Pacific Plate beneath the Eurasian Plate. Extension was the greatest during the early phase of basin formation; estimated rates of extension during the initial rifting are 2%, 6.5%, and 3.5% in the Domi, Jeju, and Socotra basins, respectively. A regional uplift terminated the rifting in the Late Eocene-Early Oligocene. Rifting and extension, although mild, resumed in the Early Oligocene; while fluvio-lacustrine deposition continued to prevail. The estimated rates of extension during the second phase of rifting are 0.7%, 0.8%, and 0.5% in the Domi, Jeju, and Socotra basins, respectively. A second phase of uplift in the Early Miocene terminated the rifting, marking the transition to the post-rift phase of regional subsidence. Regional subsidence dominated the study area between the Early Miocene and the Late Miocene. An inversion in the Late Miocene interrupted the post-rift subsidence, resulting in an extensive thrust-fold belt in the eastern part of the area. Uplift and subsequent erosion were followed by regional subsidence.  相似文献   

Discussion on “sandwich” structures and preservation conditions of shale gas in the South Yellow Sea Basin     

《China Geology》2018,1(4):485-492

In order to make a breakthrough in Mesozoic-Paleozoic shale gas exploration in the South Yellow Sea Basin, a comparison of the preservation conditions was made within the Barnett shale gas reservoirs in the Fortworth Basin, the Jiaoshiba shale gas reservoirs in Sichuan Basin and potential shale gas reservoirs in Guizhou Province. The results show that the “Sandwich” structure is of great importance for shale gas accumulation. Therein to, the “Sandwich” structure is a kind of special reservoir-cap rock assemblage which consist of limestone or dolomite on the top, mudstone or shale layer in the middle and limestone or dolomite at the bottom. In consideration of the Mesozoic-Paleozoic in the Lower Yangtze, and Laoshan Uplift with weak Paleozoic deformation and thrust fault sealing on both flanks of the Laoshan Uplift, a conclusion can be drawn that the preservation conditions of shale gas probably developed “Sandwich” structures in the Lower Cambrian and Permian, which are key layers for the breakthrough of shale gas in the South Yellow Sea. Moreover, the preferred targets for shale gas drilling probably locate at both flanks of the Laoshan Uplift.  相似文献