Lithostratigraphic revision and correlation of the Oligo‐Miocene Murray Supergroup,Western Murray Basin,South Australia     

J. J. Lukasik  N. P. James 《Australian Journal of Earth Sciences》2013,60(6):889-902

The Murray Basin in southeastern Australia is a large, shallow, intracratonic basin filled with laterally extensive, undeformed, Cenozoic carbonate and terrigenous clastic sedimentary rocks that constitute regional and locally important groundwater aquifers. The marine Oligo‐Miocene strata distributed throughout the southwestern portion of the basin are here encompassed within the Murray Supergroup. The Murray Supergroup (formerly Murray Group) incorporates the marginal marine marl and clay of the Ettrick Formation, Winnambool Formation and Geera Clay in the western and northern portions of the Murray Basin in South Australia, in addition to the limestone that outcrops along the banks of the River Murray in nearly continuous section for 175 km. The stratigraphic nomenclature of these rocks is revised as follows. The boundary between the lower and upper members of the Mannum Formation is redefined and a new Swan Reach Dolomite Member is erected. The Finniss Clay is revised to Finniss Formation possessing three new members: the Cowirra Clay Member, Portee Carbonate Member and Woolpunda Marl Member. The ‘Morgan Limestone’ is raised to Morgan Group and contains three new formations: the Glenforslan Formation, Cadell Formation (with Murbko Marl Member and Overland Corner Clay Member) and Bryant Creek Formation. The Pata Formation is redefined and described. Type and reference sections are erected for each new and revised unit, and are lithostratigraphically correlated to illustrate their stratigraphic architecture.  相似文献   

Genèse et déformation des bassins néogènes du Rif central (Maroc) au cours du rapprochement Europe-Afrique     

Lahsen Ait Brahim  Pierre Chotin 《Geodinamica Acta》2013,26(4):295-304

Résumé

Après la mise en place des nappes dans le Rif, des bassins intramontagneux se sont créés et ont subi des déformations depuis le Miocène supérieur jusqu’au Quaternaire. L’analyse microtectonique de la fracluration, et les marqueurs de tectonique synsédimentaire (tailles synsédimentaires, discordances progressives, talus de progradation) montrent que ces bassins ont été soumis à un régime tectonique compressif depuis le Tortonien. La direction de la contramte maximale compressive a changé au cours du temps depuis la direction N040 au Tortono-Messinien jusqu’à la direction N000-140 au Plio-quaternaire. L’évolution sédimentaire et tectonique de ces bassins est à mettre en relation avec l’avancée vers l’WSW du bloc d’Alboran et son blocage entre l’Europe et l’Afrique.  相似文献   

Ichnofossils from the Miocene Middle Bhuban Formation, Mizoram,Northeast India and their Paleoenvironmental Significance     

Kapesa LOKHO  Birendra P. SINGH 《《地质学报》英文版》2013,87(5):1460-1471

An ichnofossil assemblage is preserved in sediments of the Middle Bhuban Formation,Surma Group,of Miocene age from the Durtlang and Chanmari sections,Aizawl district,Mizoram,northeastern India.The studied sections comprise a thick,bioturbated and thinly bedded sandstone–silty shale facies.The preserved ichnofossils show high density and low diversity with the assemblage represented by feeding and resting traces,i.e.,Psilonichnus upsilon Frey et al.,1984,Ophiomorpha isp.,Teichichnus spiralis Mikulá.1990,Skolithos isp.,Palaeophycus isp.,and other horizontal burrows.Sedimentary structures associated with these traces are mainly cross bedding,flaser bedding and slump structures.Considering the distribution of the Psilonichnus ichnogenus across an integrated ichnological–sedimentological framework,the stratigraphic interval of the Middle Bhuban Formation,in which they occur,are interpreted to have been deposited under a shallow,marginal-marine channel complex dominated by tidal channels developed in quiet,brackish-water portions of a delta plain.  相似文献   

吉林中部断裂构造带的基本特征及其形成演化的研究     

张寿德  邵学君 《吉林地质》2013,(4):31-34

吉林中部断裂构造带位于梨树断陷东侧,断裂构造带包括南金山断裂、北金山断裂、吉林中部断裂、苏家屯断裂。本文介绍了火石岭期、沙河子期、营城期、登娄库期—泉头早期、嫩江期末期—明水期和喜马拉雅期,南金山断裂、北金山断裂、吉林中部断裂、苏家屯断裂构造形、成演化史。  相似文献   

云南双江大亮山金矿控矿因素及成因分析     

花仁忠  王琨  龙洋  伏聪 《云南地质》2013,(4):379-381

矿体赋存于韧性剪切带,矿化带近南北向分布,为岩浆期后中—低温热液通过富集作用形成的微粒、浸染型金矿.  相似文献   

Importance of active tectonics during karst formation. A Middle Eocene to Pleistocene example of the Lina Moutains (Irian Jaya,Indonesia)     

J.-M. Thery  M. Pubellier  B. Thery  J. Butterlin  A. Blondeau  C. G. Adams 《Geodinamica Acta》2013,26(3-4):213-221

Abstract

The Lina Moutains show a typical example of karst formation associated to recent and active tectonics. The limestone samples were collected from giant potholes present beneath the heavy rainforest, during speleological expeditions to the Bird’s Head of Irian-Jaya. Micropalaeontological data allow us to give a Middle Pleistocene age for the most recent karst formation. A detailed stratigraphy between the Upper Lutetian and the Middle Pleistocene was recorded, with tectonic events during the Oligocene and Pleistocene. The edge of the resurgence layer was also dated. We also conclude the probable existence of a subterraneous network downhill of the karst within the most recent levels of the Kais Limestone formation. We replace this formation within the tectonic evolution of this area between the Eocene and the Middle Pleistocene, in conjunction with the oblique convergence of the Pacific plate carrying volcanic arc fragments and the Australian margin, which resulted in folding, normal faulting associated with local extension, and wrench motion, which are settings capable of creating uplift of the carbonated platform. © Elsevier, Paris  相似文献   

The Lower Miocene volcaniclastic sedimentation in the Sicilian sector of the Maghrebian Flysch Basin: geodynamic implications     

Paola de Capoa  Angelida Di Staso  Francesco Guerrera  Vincenzo Perrone  Mario Tramontana  Mohamed Najib Zaghloul 《Geodinamica Acta》2013,26(2):141-157

Abstract

Volcaniclastic debris-rich formations, characterising the Troina-Tusa Unit in the Sicilian Maghrebian Chain, are examined. The Troina-Tusa Unit terrains sedimented in the Maghrebian Flysch Basin, which, from Jurassic to Early Miocene, constituted the southernmost branch of the Western Tethys, located between Africa and the Mesomediterranean Terrane margins. New field, biostratigraphic and pétrographie data enable a reconstruction of the palaeogeographic and structural evolution of the Flysch Basin immediately before its deformation. All the studied formations transpired to be Burdigalian in age. The sandstone compositions, showing different source areas (magmatic arc, recycled orogen and continental block), indicate a provenance for the clastic material from a crystalline basement with an active volcanic arc, replaced by a remnant volcanic arc, which was rapidly completely eroded. The source area that has been considered is Sardinia, where Upper Oligocene -Aquitanian calc-alkaline volcanites are widespread, but the sedimentological characteristics and the Burdigalian age do not fit with this provenance. The Burdigalian calc-alkaline arc should be located on the internal side of the Troina-Tusa Basin, above the already stacked Peloritanian units. A migration of the volcanic activity, connected with the subduction plain roll-back, can be envisaged from the Sardinia Block to the Peloritanian Chain, this latter still docked to the Sardinia-Corsica massif. © 2002 Editions scientifiques et médicales Elsevier SAS. All rights reserved.  相似文献   

Stages in the Magura Basin: a case study of the Polish sector (Western Carpathians)     

《Geodinamica Acta》2013,26(1-3):83-100

The Magura Basin domain developed in its initial stage as a Jurassic-Early Cretaceous rifted passive margin that faced the eastern parts of the oceanic Alpine Tethys. In the pre- and syn-orogenic evolution of the Magura Basin the following prominent periods can be distinguished: Middle Jurassic-Early Cretaceous syn-rift opening of basins (1) followed by Early Cretaceous post-rift thermal subsidence (2), latest Cretaceous–Paleocene syn-collisional inversion (3), Late Paleocene to Middle Eocene flexural subsidence (4) and Late Eocene - Early Miocene synorogenic closing of the basin (5). The driving forces of tectonic subsidence of the basin were syn-rift and thermal post-rift processes, as well as tectonic loads related to the emplacement of accretionary wedge. This process was initiated at the end of the Paleocene at the Pieniny Klippen Belt (PKB)/Magura Basin boundary and was completed during Late Oligocene in the northern part of the Magura Basin. During Early Miocene the Magura Basin was finally folded, thrusted and uplifted as the Magura Nappe.  相似文献   

东昆仑祁漫塔格花岗片麻岩记录的岩浆和变质事件   总被引：14，自引：6，他引：8  

孟繁聪  崔美慧  吴祥珂  吴久芳  王建华 《岩石学报》2013,29(6):2107-2122

东昆仑青海祁漫塔格尕林格一带原定为金水口群的眼球状花岗片麻岩,实际为新元古代早期形成的花岗岩.采用SHRIMP和LA-MC-ICP-MS两种方法对其中的锆石进行了测试,获得的年龄分别为938±5Ma和938±2Ma,代表了花岗岩的形成时代.花岗岩地球化学特征显示为S-型,属于钙碱性系列的弱过铝-过铝质花岗岩,εNd(0)为-9.4～-11.7,εNd(t=938Ma)为-0.6～-3.2,显示低的负值,tDM为1.6 ～2.1Ga,推测其源岩与白沙河岩组类似.东昆仑东段、柴北缘以及阿尔金均有1000～900Ma的花岗岩形成,表明这次岩浆活动比较广泛,可能与我国西部不同陆块间的汇聚有关,是我国西部新元古代克拉通基底形成的反映,同时也响应于全球Rodinia超大陆的形成.花岗片麻岩中1粒锆石边部获得了416±11Ma的年龄,与区域上志留-泥盆纪花岗岩形成时代一致,代表了新元古代花岗岩发生变质作用的时代,其中白云母40Ar/39Ar的坪年龄和等时线年龄为406±2Ma,代表了变质花岗岩的冷却年龄,这些年龄表明新元古代花岗岩卷入了古生代中期与祁漫塔格洋/海盆关闭有关的造山事件.  相似文献   

阿尔金断裂带中侏罗世走滑活动及其断裂规模的探讨 ——来自软沉积物变形的证据   总被引：3，自引：0，他引：3  

龚正  李海兵  孙知明  刘栋梁  潘家伟  韩亮  吴蝉 《岩石学报》2013,29(6):2233-2250

阿尔金断裂带是青藏高原北部边界,它不仅切割了高原北部的不同构造单元,控制了高原北部的几何学特征及基本的构造格架,而且还是调节青藏高原变形和高原物质向东挤出的重要断裂之一,对它的形成时代、活动历史以及断裂带的生长过程和演化的研究是认识青藏高原形成过程和动力学问题的关键之一.本文以阿尔金断裂带中段肃北县城南部出露的中侏罗纪陆相湖沼地层为研究对象,在野外中侏罗世剖面中,共发现26层软沉积物变形层.软沉积物变形的方式主要是不同类型的砂土液化,包括负载、球-枕状构造、卷曲变形、液化角砾、液化底劈和砂火山构造;软沉积变形大多发生在细砂岩和泥质粉砂岩层中,细砂岩层易液化、变形剧烈;粒度统计显示发生液化的沙粒粒径在0.05～0.5mm之间,主要为0.2～0.3mm,这些砂土液化的软沉积物变形特征与历史地震和模拟实验获取的易液化扰动区间高度一致,因此,中侏罗世地层中发育的软沉积物变形是由于地震震动而形成.根据震级与液化最大震中距的关系,推测发生的最小震级在Ms6～6.5之间,根据软沉积变形的类别与震级之间的关系推断最大可能发生的震级为7.5级.根据软沉积变形层出现的频率和组合关系,我们认为肃北剖面反应的是一个地震幕,发生的地震事件至少在4次以上,表明在中侏罗世(古)阿尔金断裂带发生了强烈的走滑运动,并且至少断裂带已延展到肃北一带,结合索尔库里地区晚三叠纪左旋走滑活动形成的糜棱岩以及玉门地区白垩纪的火山活动和软沉积物变形的事实,指示着阿尔金断裂带至少经历了晚三叠纪、中侏罗纪、晚白垩纪及新近纪的强烈走滑活动,并且其断裂带由索尔库里地区向东西两端逐渐扩展生长,由早期百千米到上千千米、一千多千米至约两千千米长的现今规模.  相似文献