Tracing sediment pathways by zircon fission track analysis: Oligocene marine connections in Central Europe     

Cornelia Spiegel  Joachim Kuhlemann  Wolfgang Frisch 《International Journal of Earth Sciences》2007,96(2):363-374

In this study, we use contrasting zircon fission track age signatures of Alpine detritus and detritus derived from the Variscan realm to trace sediment pathways in Central Europe. Our data show that the Molasse Basin was connected with the Rhine Graben Sea during the Mid-Oligocene, thus joining the North Sea to the Paratethys. Within the Rhine Graben Sea, fairly strong south–north directed currents existed, transporting sand-sized Alpine detritus nearly 300 km towards the north. A connection between the Rhône-Bresse Graben and the Rhine Graben and/or the French Molasse Basin and the Swiss Molasse Basin, by contrast, is not supported by the fission track data. This may be explained by the existence of submarine rises that hampered the transport of sand-sized sediment towards the north/northeast.  相似文献   

Interacting tectonics,hydrogeology and karst processes in an intramontane basin: the Jiloca graben (NE Spain)   总被引：1，自引：0，他引：1  

José C. Rubio  José L. Simón  M. A. Soriano 《Hydrogeology Journal》2007,15(8):1565-1576

The Jiloca basin is a NNW–SSE trending, Neogene-Quaternary graben in NE Spain, bounded by normal faults with measurable hectometre-scale throws. Its overall trend truncates previous NW–SE folds. The sedimentary infilling includes Neogene and Quaternary deposits, exceeding 80 m in thickness. The stratigraphical and structural setting controls hydrogeology of the basin. Neogene marls constitute an aquiclude that separates a main Jurassic karstic, confined aquifer from a shallow, unconfined Plio-Quaternary aquifer. The Jurassic aquifer is laterally compartmented by impervious Upper Triassic anticline cores, though its piezometric surface usually lies 30–60 m higher than the Mesozoic-Neogene boundary. The geological, and specifically the hydrogeological features are not significantly compatible with a previously published hypothesis that considers the Jiloca depression as a polje (in which the final topography is the result of suballuvial karstic corrosion) for three reasons. First, the hypothetical corrosion front shows neither a specific relationship with the epiphreatic zone, nor control by the local presence of impervious Triassic rocks. Second, chemistry of groundwater at the underlying Jurassic aquifer would not allow limestone dissolution at rates necessary for producing the supposed erosion deepening of 300 m since the late Pliocene. Finally, no evidence of swallow holes or ponors has been found.  相似文献   

伊通地堑岔路河断陷南段构造-沉积特征与油气藏类型     

王剑  徐翔军  陈秀艳  李本才  王伟涛 《世界地质》2007,26(2):240-244,253

伊通地堑岔路河断陷南段,在地堑西北缘断层及二号断层(F2)的制约下,主要分为梁家构造带和新安堡凹陷两个二级构造单元。根据三维地震资料进行系统的构造解析认为,该区可划分为滚动背斜带、断块隆起带和走滑断陷带三个构造带。该区沉积相类型及其展布规律主要受控于东南缘断层、西北缘断层及F2断层的构造活动。受不同的构造-沉积特征制约,形成西北缘边界断层下的断层-岩性油气藏、中央隆起带断块式油气藏、F2断层控制的构造-岩性复合油气藏。  相似文献   

Episodic mineralization of hydrothermal illite in the Soultz-sous-Forêts granite (Upper Rhine Graben, France)     

Anja M. Schleicher  Laurence N. Warr  Bernd Kober  Emmanuel Laverret  Norbert Clauer 《Contributions to Mineralogy and Petrology》2006,152(3):349-364

Episodic and localized illite mineralization is documented in the hydrothermally altered Soultz-sous-Forêts granite (Upper Rhine Graben, France). Separated grain-size fractions of altered granite and argillite vein samples contain mixtures of 2M₁ and 1M trans-vacant illite varieties. The platy pseudohexagonal 2M₁ illite phases dominate the vein fillings, whereas the 1M illite occurs largely as a fibrous pore-filling variety, which is particularly abundant in the granite matrix. Multiple phases of fluid injections into the granite body have resulted in different illite assemblages, each sample containing a mixture of polytype generations formed during different crystal growth events. On the basis of mineralogical and K–Ar isotopic constraints, the ages of these vein-mineralizing events are determined by plotting the K–Ar values of the various grain-size fractions against polytype abundance and the fitted volume-weighted crystallite thickness distributions. The results suggest a Permian age for the formation of the studied argillite veins, characterized by successive injections of hydrothermal fluids. Secondary episodes of illite crystallization occurred during Jurassic and Cretaceous (or even younger times) in both the veins and the granite matrix. There are indications that the polytype structure and composition of illite were strongly influenced by variations in fluid chemistry and the degree of fluid–rock interaction as the granite was progressively sealed during post-Variscan, episodic hydrothermal activity.  相似文献   

The hydrogeology and hydrogeochemistry of the Barwon Downs Graben aquifer, southwestern Victoria, Australia   总被引：1，自引：0，他引：1  

B. Petrides  I. Cartwright 《Hydrogeology Journal》2006,14(5):809-826

The Barwon Downs Graben lies on the northern flanks of the Otway Ranges and is situated approximately 70 km southwest of Geelong, Victoria, Australia. The major lower Tertiary Barwon Downs Graben aquifer comprises highly permeable sands and gravels interbedded with clays and silts of the hydraulically interconnected Pebble Point, Dilwyn and Mepunga Formations. Groundwater flows east into the Barwon Downs Graben from the Barongarook High, and yields ¹⁴C ages up to ～20 ka implying that recharge rates are low and, consequently, that the resource could be impacted by overabstraction. The presence of three different lithological units has led to the development of localized flow systems that has resulted in a lack of regular spatial variations in groundwater chemistry. Stable isotopic data suggests that groundwater was recharged under similar climatic conditions as of today. The major ion chemistry of the freshest groundwater is dominated by Na and HCO₃ while higher TDS groundwater, from the confining Narrawaturk Marl, is dominated by Na and Cl. Cl/Br ratios are close to rainfall suggesting that halite dissolution is not the principle source of salts. An excess of Na relative to Cl in fresher groundwater suggests that feldspar dissolution has occurred, however, water–rock interaction is limited. The concentrations of Ca, Mg, and SO₄ are controlled by silicate dissolution and ion-exchange reactions with clays.  相似文献   

Deep seismic investigation across the Barents–Kara region and Novozemelskiy Fold Belt (Arctic Shelf)     

N.M. Ivanova  T.S. Sakoulina  Yu.V. Roslov 《Tectonophysics》2006,420(1-2):123

Since 1995 SEVMORGEO has collected wide-angle reflection/refraction profiling (WARRP), multichannel seismic data (MCS) and seismoacoustic profiling, along regional lines 1-AR, 2-AR and 3-AR. These lines cross the whole Barents–Kara Region and Novozemelskiy Fold Belt. As a result, new geological data about the deep structure of the Earth's crust have become available. Four main tectono-stratigraphic units are distinguished in the section of the Earth's crust: (1) a sedimentary cover; (2) the Upper Proterozoic (mainly Riphean for the Barents Plate) and Riphean–Paleozoic (the South-Kara Syneclise) deformed and folded complexes; (3) the upper crystalline crust (granite-gneissic metamorphic Archean–Proterozoic complex); (4) the lower crust (basalt complex). The Barents–Kara Region is characterized by moderately thinned continental and subcontinental crust with an average thickness of 37–39 km. On islands and areas of uplifts with ancient massifs, the thickness of the crust (38–42 km) approaches the typical crust for a continental platform. In the Novozemelskiy Fold Belt the thickness of the crust reaches 40–42 km. Rift-related grabens are characterized by significant crustal thinning with thicknesses of 33–36 km. Several grabens are revealed: the Riphean Graben on the Kola-Kanin Monocline, the Lower Paleozoic West-Kola Graben, the Devonian Demidovskiy Aulacogen, the Upper Paleozoic Malyginskiy Graben in the Barents Region and Upper Paleozoic–Triassic Noyabr'skiy and the Chekinskiy grabens in the Kara Region. Data concerning the deep structure lead us to conclude that mainly destructive processes contributed to the dynamics of the forming of the Barents–Kara Region.  相似文献   

北海盆地维京地堑新近纪下切谷发育主控因素及其内部充填特征^*          下载免费PDF全文

罗铃钞  纪友亮  王皓 《古地理学报》2017,19(4):635-647

下切谷是陆地上一种常见的侵蚀地貌,古今均十分发育,但是不同盆地、不同时代发育的下切谷,无论是在沉积充填特征还是平面展布形态等多个方面都大相径庭。为此,作者依据曼宁公式进行理论推导,再结合分析北海盆地维京地堑发育的典型下切谷实例以及前人进行的相关水槽实验结果总结认为: 地形坡度、基准面下降速率及幅度与下切谷所侵蚀地层的岩性是影响下切谷发育模式的最主要因素。这些因素共同控制了: (1)下切谷的弯度指数及宽深比,(2)下切谷平面上发育密度及其规模,(3)与下切谷伴生的陆棚三角洲、陆棚边缘三角洲沉积厚度及展布范围。海侵过程中下切谷的沉积充填类型及岩性,受平均基准面上升速率及沉积物供应量的共同控制,根据沉积充填类型及岩性的不同可将其划分为富砂型陆棚三角洲充填及富泥型河口湾充填两类。  相似文献   

Effect of small potassium-rich dykes on regional gamma-spectrometry image of a potassium-poor volcanic complex: A case from the Doupovské hory Volcanic Complex, NW Czech Republic   总被引：1，自引：0，他引：1  

Skcelov Zuzana  Rapprich Vladislav  Ml och Bed&#x;ich 《Journal of Volcanology and Geothermal Research》2009,187(1-2):26-32

Basaltic rocks with low K, U and Th contents dominate the entire Volcanic Complex of the Doupovské hory Mts. Significant potassium anomaly exceeding 1.5 atomic wt.% of potassium over an area of 4 × 8 km and 2 atomic wt.% of potassium over an area of 2 × 6 km was defined by airborne gamma-ray spectrometry above the central part of the Doupovské hory Volcanic Complex. The following detailed field study, supported by field and laboratory gamma-spectrometry measurements and geochemical analyses of rock samples, resulted in discovery of a swarm of potassium-rich trachytic dykes. The existence of such highly-differentiated rocks in the volcanic complex was unknown till present. These dykes are commonly less than 1 m wide, but their potassium content varies between 4 and 8 atomic wt.%. Owing to this high-K composition and relative abundance of dykes, the dyke rocks significantly modify the regional pattern of gamma-spectrometry data. The potassium anomaly cannot be explained by the presence of Flurbühl intrusive body dominated by ijolites and essexites, as all these rocks are poor in K, with potassium typically not exceeding 1.5 wt.%. On the other hand, much more extensive intermediate trachybasaltic lavas with K content varying within the range 1.8–3 wt.% cause only minor or undetectable anomalies.  相似文献   

海拉尔盆地乌尔逊断陷构造特征和基底伸展量研究   总被引：3，自引：1，他引：2  

黄超义  刘志宏  高军义 《世界地质》2005,24(1):48-52

乌尔逊断陷是海拉尔盆地最大箕状断陷,主要形成于早白垩世,由向东倾斜的主控断层及其上发育的一系列与之同向的犁式正断层和反向层组合构成。本文用基底伸展量(I)、伸展率(e)、伸展系数（β)来定量描述乌尔逊断陷在拉张作用下发生伸展运动前后的变化量,采用直接测量法得到三个参数,并绘出基底伸展量的发育图,得出乌尔逊断陷基底伸展量在断陷内变化很小、断陷中部伸展量变化相对较大、南北两端相对较小、平均伸展量10．5、伸展率为0．81％及伸展系数为1．81的结论。  相似文献   

Application of Multi-well Subsidence Analysis of the Beryl Embayment,Viking Graben, Northern North Sea     

Jon D. TURNER  Roger A. SCRUTTON 《《地质学报》英文版》2006,80(5):693-704

1 Introduction A series of studies have indicated that there were two extensional phases in the North Sea (Fig. 1). An earlier period (Late Permian-Early Triassic) of rifting occurred widely in these areas, with predominant extension direction of W-E (F?rseth, 1996; F?rseth et al., 1997). In contrast to the widely distributed Permo-Triassic extension, Jurassic extension in the North Sea were generally much more localized into the three main rift arms (Fig. 1): the Viking Graben, Moray…  相似文献