共查询到20条相似文献，搜索用时 656 毫秒
1.
陕西镇安西口石炭系/二叠系界线剖面碳酸盐岩微相特征与沉积环境的研究 总被引：18，自引：0，他引：18
在陕西镇安西口从上石炭统逍遥阶和下杨家河阶到下二叠统上杨家河阶、范家河阶、垭口阶和隆林阶的地层剖面上,区分出10种碳酸盐岩微相类型,即含生物碎屑灰泥灰岩、生物碎屑粒泥灰岩、生物碎屑泥粒灰岩、粒泥灰岩—泥粒灰岩、粗枝藻粒泥灰岩—粗枝藻泥粒灰岩、腕足棘皮粒泥灰岩—腕足棘皮泥粒灰岩、生物碎屑颗粒灰岩、团块颗粒灰岩、核形石颗粒灰岩和含鲕粒团块颗粒灰岩。它们形成于开阔台地和台地边缘浅滩2种沉积环境,开阔台地又进一步分为较浅水的开阔台地浅滩和较深水的开阔台地滩间,台地边缘浅滩内则局部发育藻丘。在此基础上,识别出在晚石炭世逍遥期至早二叠世隆林期研究区发生过12次相对海平面波动,它们构成5次明显的相对海平面升降;最后讨论了三里冲剖面上各阶界线与海平面变化的关系。 相似文献
2.
S. V. Rud’ko 《Lithology and Mineral Resources》2018,53(4):307-323
The paper presents results of the lithological study of Upper Jurassic limestones, flyschoids and limestone breccias on the southern side of the Baidar Valley in the Crimean Mountains. Study of the microfacies revealed that the limestones are represented by deposits on lagoons, platform edge shoals, reefs, and forereef aprons on the carbonate platform slope. Flyschoids include deposits in the distributive turbidite channels and hemipelagic sediments in the deep-water part of the basin. Limestone breccias were formed by gravitation flows on the carbonate platform toe-of-slope and slope. The presence of gravitation deposits in the Upper Jurassic carbonate complexes of the Crimean Mountains can testify to the primary clinoform structure of this sedimentary sequence. Comparison of the obtained sedimentological data made it possible to reconstruct the facies model of the Crimean carbonate platform and main episodes of its formation. Development of the carbonate shelf was related to two transgressive-regressive cycles. A dome-shaped reef was formed away from the coast at the initial (Oxfordian) stage. The carbonate platform was formed at the early Kimmeridgian lowstand stage when sediments were deposited in the internal part of the platform adjacent to land. In the late Kimmeridgian and early Tithonian, configuration of the carbonate platform profile resembled a distally steepened ramp, and its active progradation and shelf expansion took place in the course of transgression. Regression in the late Tithonian–early Berriasian led to regressive transformation of the ramp into platform with a flattened shallow-water shelf. Tectonic deformations at the Jurassic/Cretaceous transition promoted the formation of megabreccias on the carbonate platform foreslope. The tectonically reworked rock sequence of the “extinct” carbonate platform was overlapped transgressively by the upper Berriasian or lower Valanginian, relatively deep-water deposits of the Cretaceous platform cover. 相似文献
3.
云南永德鱼塘寨石炭－二叠系界线剖面的生物地层学及沉积环境 总被引：1，自引：0，他引：1
云南永德鱼塘寨石炭－二叠界线剖面沉积连续、化石丰富，可作为滇西地区的代表性剖面，自石洞寺组至草坝山头组底部灰岩可划分出１６种主要的碳酸盐微相类型，分别形成于外陆架、中陆架和内陆架环境。 相似文献
4.
During the Moscovian Age, the eastern part of the Russian Platform was occupied by the shallow-water East European Basin (EEB) characterized by predominantly carbonate sedimentation. In the Cis-Ural region of this basin, the deep Cis-Ural Sea (CUS) occupied the Ural Foredeep. The Paleo-Ural Range separated the CUS from the narrow and long East Ural Gulf, which was connected in the south with the main part of the EEB and a sea within the Turan Plate. The Moscovian paleogeographic setting is shown in three paleogeographic maps. Middle Carboniferous organogenic buildups from the eastern slope of the Urals have been time and again described previously. However, the repeated study of these features did not prove the biogenic nature of all of them. This work presents characteristics of two, newly discovered, unique (in terms of nature and structure) coastal bioherms. One bioherm lies at the base of the Moscovian stage and consists of phylloid algae. The second bioherm, located at a higher level, has a complex structure and is made up of foraminifers, algae, and stromatolites. After the desiccation and development of karst features on the surface, the bioherm was buried under sandy–clayey sediments accumulated in freshened water. 相似文献
5.
《International Geology Review》2012,54(3):282-295
The development of the Yugoslavian, Albanian, and Italian segments of the Mediterranean geosyncline is compared, using the province of Montenegro as the standard for correlation of the paleogeographic analysis during the Alpine tectonic cycle. The tectonic zones, characteristic of the Montenegro area are four in number and given as the Maritime zone with rocks ranging from Upper Carboniferous to Oligocene; the old Montenegro zone consisting of Triassic, Jurassic, Cretaceous and upper Oligocene sediments; the Ku?a zone deposits ranging from Upper Permian through Mesozoic; and the Durmitor zone with Devonian, Carboniferous, Permian, Triassic, and Jurassic sedimentary and volcanic-sedimentary bodies and Upper Cretaceous flysch.—IGR Staff. 相似文献
6.
东天山大南湖岛弧带石炭纪岩石地层与构造演化 总被引：5，自引：0，他引：5
详细的地质解剖工作表明,东天山地区大南湖岛弧带石炭纪出露4套岩石地层组合,即早石炭世小热泉子组火山岩、晚石炭世底坎儿组碎屑岩和碳酸盐岩、晚石炭世企鹅山组火山岩、晚石炭世脐山组碎屑岩夹碳酸盐岩。根据其岩石组合、岩石地球化学、生物化石、同位素资料以及彼此的产出关系,认为这4套岩石地层组合的沉积环境分别为岛弧、残余海盆、岛弧和弧后盆地。结合区域资料重塑了大南湖岛弧带晚古生代的构造格架及演化模式。早、晚石炭世的4套岩石地层组合并置体现了东天山的复杂增生过程。 相似文献
7.
Melanges play a key role in the interpretation of orogenic belts, including those that have experienced deformation and metamorphism during continental collision. This is exemplified by a Palaeozoic tectonic-sedimentary melange (part of the Konya complex) that is exposed beneath a regionally metamorphosed carbonate platform near the city of Konya in central Anatolia. The Konya complex as a whole comprises three units: a dismembered, latest Silurian–Early Carboniferous carbonate platform, a Carboniferous melange made up of sedimentary and igneous blocks in a sedimentary matrix (also known as the Hal?c? Group or S?zma Group), and an overlying Volcanic-sedimentary Unit (earliest Permian?). The Palaeozoic carbonates accumulated on a subsiding carbonate platform that bordered the northern margin of Gondwana, perhaps as an off-margin unit. The matrix of the melange was mainly deposited as turbidites, debris flows and background terrigenous muds. Petrographic evidence shows that the clastic sediments were mostly derived from granitic and psammitic/pelitic metamorphic rocks, typical of upper continental crust. Both extension- and contraction-related origins of the melange can be considered. However, we interpret the melange as a Carboniferous subduction complex that formed along the northern margin of Gondwana, related to partial closure of Palaeotethys. Blocks and slices of Upper Palaeozoic radiolarian chert, basic igneous rocks and shallow-water carbonates were accreted and locally reworked by gravity processes. Large (up to km-sized) blocks and slices of shallow-water limestone were emplaced in response to collision of the Palaeozoic Carbonate Platform with the subduction zone. The overlying Volcanic-sedimentary Unit (earliest Permian?) comprises alkaline lava flows, interbedded with volcaniclastic debris flows and turbidites, volcanogenic shales and tuff. The complex as a whole is overlain by shallow-water, mixed carbonate–siliciclastic sediments of mainly Late Permian age that accumulated on a regional-scale shelf adjacent to Gondwana. Successions pass transitionally into Lower Triassic rift-related shallow-water carbonates and terrigenous sandstones in the southwest of the area. In contrast, Triassic sediments in the southeast overlie the melange unconformably and pass upwards from non-marine clastic sediments into shallow-marine calcareous sediments of Mid-Triassic age, marking the base of a regional Mesozoic carbonate platform. During the latest Cretaceous–Early Cenozoic the entire assemblage subducted northwards and underwent high pressure/low temperature metamorphism and polyphase folding as a part of the regional Anatolide unit. 相似文献
8.
The work discusses peculiarities of sedimentation during the onset and middle phase of the postrift subsidence in the southern
part of the East European Platform corresponding to the Early and Middle Carboniferous epochs, which were marked by an accumulation
of the most contrasting (in lithology and formation setting) sediments: coals and radiolaria-bearing domanikoid rocks. These
are the early-middle Visean (Early Carboniferous) and late Bashkirian-early Moscovian (Middle Carboniferous) epochs. It should
be noted that precisely these epochs were marked by a substantial renewal in faunal and floral communities, which also resulted
from the new phase of the postrift subsidence. Radiolaria-bearing domanikoid facies were formed in the marine basin with normal
salinity. The reconstruction of sedimentation settings indicates that shallow-water sediments (algal limestones) of the inner
shelf were separated from deep-sea domanikoid facies of the outer shelf and, probably, continental slope by a chain of bioherms
with an apron of organogenic-detrital limestones or spiculebearing facies. 相似文献
9.
早石炭世海侵范围较小，莫莫克以东为古岛，以西为向北西倾斜的水下隆起，为局限台地--开阔台地相清水碳酸盐岩和混积陆棚相沉积：晚石炭世早期海侵范围扩大．铁克力克古岛沦为水下隆起，莫莫克以西为较厚的混积陆棚相和滨岸相砂岩沉积．以东为局限台地-开阔台地相清水碳酸盐岩沉积；晚石炭世中期为稳定的海侵期，形成潮坪-局限台地．开阔海台地相清水碳酸盐岩沉积：晚石炭世晚期--一早二叠世早期为规模最大的海侵期，也是塔西南碳酸盐岩台地发育的鼎盛时期，其重要标志是形成了台地边缘礁滩相带，高能浅滩相最为发育．莫莫克以西地区下二叠统棋盘组为海陆交互相沉积、上二叠统达里约尔组为湖泊一河流相沉积．莫莫克以东地区下二叠统普司格组为河流-湖泊-扇三角洲相沉积、上二叠统杜瓦组为冲积扇-扇三角洲相沉积． 相似文献
10.
The Bálvány North Permian-Triassic boundary sediments were deposited on a carbonate platform in the tropical part of the western Paleo Tethys ocean.The overall elemental geochemistry of the detailed two-metre-thick section across the boundary that we studied shows that the clastic content of the sediments came from dominantly silica-rich continental sources though with some more silica-poor inputs in the uppermost Permian and lowest Triassic limestones as shown by Ni/Al and Nb/Ta ratios.These inputs bracket, but do not coincide with, the main extinctions and associated C, O and S changes.Increased aridity at the Permian-Triassic boundary with increased wind abrasion of suitable Ti-bearing heavy minerals accounts for both the high Ti/Al and Ti/Zr ratios.Various geochemical redox proxies suggest mainly oxic depositional conditions, with episodes of anoxia, but with little systematic variation across the Permian–Triassic extinction boundary.The lack of consistent element geochemical changes across the Permian-Triassic boundary occur not only in adjacent shallower-water marine sections, and in other marine sections along the SW Tethys margin such as the Salt Range sections in Pakistan, but also in deeper shelf and oceanic sections, and in non-marine African and European continental sediments.In the absence of significant changes in physical environments, chemical changes in the atmosphere and oceans,reflected in various isotopic changes, drove the Permian–Triassic extinctions. 相似文献
11.
On the basis of stratigraphical and geological data, paleogeographical and palinspastic reconstructions of the Kazakhstan Paleozoides were done; their multistage geodynamic evolution was considered; their tectonic zoning was proposed. The main stages are described: the initiation of the Cambrian and Ordovician island arcs; the development of the Kazakhstan accretionary–collisional composite continent in the Late Ordovician as a result of continental subduction and the amalgamation of Gondwana blocks with the island arcs (a long granitoid collisional belt also formed in this period); the development of the Devonian and Carboniferous–Permian active margins of the composite continent and its tectonic destruction in the Late Paleozoic.In the Late Ordovician, compensated terrigenous and volcanosedimentary complexes formed within Kazakhstania and developed in the Silurian. The Sakmarian, Tagil, Eastern Urals, and Stepnyak volcanic arcs formed at the boundaries with the Ural, Turkestan, and Junggar–Balkhash Oceans. In the late Silurian, Kazakhstania collided with the island arcs of the Turkestan and Ob'–Zaisan Oceans, with the formation of molasse and granite belts in the northern Tien Shan and Chingiz. This was followed by the development of the Devonian and Carboniferous–Permian active margins of the composite continent and the inland formation of the Early Devonian rift-related volcanosedimentary rocks, Middle–Late Devonian volcanic molasse, Late Devonian–Early Carboniferous rift-related volcanosedimentary rocks, terrigenous–carbonate shelf sediments, and carbonaceous lake–bog sediments, and the Middle–Late Carboniferous clastic rocks of closed basins. In the Permian, plume magmatism took place on the southern margin of the Kazakhstan composite continent. It was simultaneous with the formation of red-colored molasse and the tectonic destruction of the Kazakhstan Paleozoides as a result of a collision between the East European and Kazakhstan–Baikal continents. 相似文献
12.
上扬子石炭-二叠纪海相碳酸盐的锶同位素演化与全球海平面变化 总被引：29，自引：1，他引：29
地质历史中海水的锶同位素组成是时间的函数,全球海平面变化是其最主要的控制因素,上扬子地区石炭-二叠纪海相碳酸盐的锶同位素演化曲线与海平面变化曲线有着很好的一致性。锶同位素演化曲线说明:1)早石炭世是一个海水逐渐加深的全球海平面上升时期,锶同位素最小值所显示的最大海泛面的年龄为 34 2Ma,位于杜内阶和韦宪阶的界线上 ;2 )晚石炭世是一个全球海平面下降时期 ;3)整个二叠纪都是全球海平面上升时期,晚二叠世的海平面上升不仅幅度大,而且海水在短时间内迅速加深 ;4)晚二叠世具有古生代海相碳酸盐的锶同位素最小值,显示晚二叠世末的全球淹没事件,最大海泛面的年龄为 2 5 0Ma,正好在二叠 /三叠纪界线附近 ;5 )二叠 /三叠纪之交的全球生物绝灭事件可能与二叠世末的全球淹没事件有关。 相似文献
13.
《地学前缘(英文版)》2016,(5)
The late Paleozoic evolution of the Wulijishanhen(WSH)-Shangdan(SD) area near to the Chaganchulu Ophiolite belt is reinterpreted. Analysis of the upper Carboniferous to lower Permian sedimentary sequence, biological associations, detrital materials, sandstone geochemistry and volcanic rocks indicates that the SD area was an epicontinental sea and rift during the late Paleozoic rather than a large-scale ocean undergoing spreading and closure. This study reveals that the actual evolution of the study area is from the late Carboniferous to the early Permian. The fusulinids Triticites sp. and Pseudoschwagerina sp.in the limestones demonstrate that the Amushan Formation develops during the late Carboniferous to the early Permian. The limestones at the base of the SD section indicate that it is a stable carbonate platform environment, the volcanic rocks in the middle of the sequence support a rift tectonic background, and the overlying conglomerates and sandstones are characteristic of an epicontinental sea or marine molasse setting. The rift volcanism made the differences in the fossil content of the SD and WSH sections and led to two sections expose different levels within the Amushan Formation and different process of tectonic evolution. Moreover, the geochemical characteristics and detrital materials of the sandstones show that the provenance and formation of the sandstones were related to the setting of active continental margin. The quartz-feldspar-lithic fragments distribution diagram indicates that the material source for the sandstones was a recycled orogenic belt. Thus, the source area of the sandstones may have been an active continental margin before the late Carboniferouseearly Permian. The characteristics of the regional tectonic evolution of the area indicate that the region may form a small part of the Gobie Tianshan rift of southern Mongolia. 相似文献
14.
15.
地质历史中海水的锶同位素组成是时间的函数，全球海平面变化是其最主要的控制因素，上扬子地区石炭—二叠纪海相碳酸盐的锶同位素演化曲线与海平面变化曲线有着很好的一致性。锶同位素演化曲线说明:1）早石炭世是一个海水逐渐加深的全球海平面上升时期，锶同位素最小值所显示的最大海泛面的年龄为342 Ma，位于杜内阶和韦宪阶的界线上；2）晚石炭世是一个全球海平面下降时期；3）整个二叠纪都是全球海平面上升时期，晚二叠世的海平面上升不仅幅度大，而且海水在短时间内迅速加深；4）晚二叠世具有古生代海相碳酸盐的锶同位素最小值，显示晚二叠世末的全球淹没事件，最大海泛面的年龄为250 Ma，正好在二叠/ 三叠纪界线附近；5）二叠/ 三叠纪之交的全球生物绝灭事件可能与二叠世末的全球淹没事件有关。 相似文献
16.
Honarmand Maryam Li Xian-Hua Nabatian Ghasem Neubauer Franz 《Mineralogy and Petrology》2017,111(5):659-675
Mineralogy and Petrology - The Lower Permian Hasan-Robat syenogranite occurs as a single pluton and intruded the Upper Carboniferous–Lower Permian sandstones and dolomitic limestones in the... 相似文献
17.
雪峰古陆边缘沅陵地区的上石炭统岩性特殊,以灰岩为主平白云质灰岩、砾屑灰岩与砾岩、砂岩相互成层,交替出现,因此,相对海平面升降变化在这种类型沉积中表现明显,利用层序地层的研究。上石炭统为１个三级层序,底部以Ｉ型层序与震旦系留茶坡组硅质岩接触;顶部仍以Ｉ型层序边界与下二叠统黔阳组成邻。包括低水位体系域、海进体系域和高水位体系域;依据准层序的叠是分为两个准层序组,即海进体系域和高水位体系域。 相似文献
18.
位于西藏冈底斯带的甲马弧内盆地是随着甲马岛弧的发育而产生的，沉积了一套演浅海相活动大陆边缘的沉积物，主要由碎屑岩与海绵礁灰岩构成，在盆地内的上侏罗统至白垩系中，共识别出七个3级层序，包括1个I类层序和6个Ⅱ类层序，重新建立了该区层序地层年代格架，层序地层的研究表明，盆地的演化可划分为具深切谷的碎屑陆架阶段，碳酸盐台地与海绵礁形成阶段，滞流的碎屑陆架阶段，无障壁海岸的碎屑陆架阶段和具障壁海岸的碎屑陆架5个阶段。 相似文献
19.
A. Van Heeswijck 《Australian Journal of Earth Sciences》2013,60(3):417-426
Upper Carboniferous to Lower Permian sedimentary rocks extend along the periphery of the northern Sydney Basin, a sub‐basin of the Sydney‐Gunnedah‐Bowen Basin complex. The basin contains basal basalts and volcanic sediments deposited in a nascent rift zone. This rift zone was created through crustal thinning during trench rollback on the eastern edge of the New England Orogen. Thermal subsidence created accommodation for predominantly marine Dalwood Group sediments. Clastic sedimentation then occurred in the Maitland‐Cessnock‐Greta Coalfield and Cranky Corner Basin during the Early Permian. This occurred on a broad shelf undergoing renewed thermal subsidence on the margin of a rift flank of the Tamworth Belt of the southern New England Orogen. Braidplain fans prograded or aggraded in two depositional sequences. The first sequence commences near the top of the Farley Formation and includes part of the Greta Coal Measures, while the second sequence includes the majority of the Greta Coal Measures and basal Branxton Formation. Thin, areally restricted mires formed during interludes in a high sedimentation regime in the lowstand systems tracts. As base‐level rose, areally extensive mires developed on the transgressive surface of both sequences. A paludal to estuarine facies changed to a shallow‐marine facies as the braidplain was transgressed. The transgressive systems tracts continued to develop with rising relative sea‐level. Renewed uplift in the hinterland resulted in the erosion of part of the transgressive systems tract and all of the highstand systems tract of the lower sequence. In the upper sequence a reduction in relative sea‐level rise saw the development of a deltaic to nearshore shelf highstand systems tract. Extensional dynamics caused a fall in relative base‐level and the development of a sequence boundary in the Branxton Formation. Finally, renewed thermal subsidence created accommodation for the overlying, predominantly marine Maitland Group. 相似文献
20.
In the western fold-and-thrust belt of the southern Urals, the Kübler and Árkai indices determined on shales, slates and phyllites record an increase from lower late diagenetic to epizonal grade from west to east. The metamorphic grade varies strongly within the different tectonic segments, which are separated by major thrusts. The increase of diagenetic and incipient metamorphic grade from the footwall to the hanging wall of all major Upper Palaeozoic thrusts indicates a pre-Permo/Triassic origin. West of the Avzyan thrust zone, the diagenetic to incipient metamorphic grade is related to the Palaeozoic basin development and reached the final grades in Late Carboniferous to Early Permian times. East of the first Avzyan thrust in the Yamantau anticlinorium, the diagenetic to lower greenschist metamorphic grade is possibly of Neoproterozoic origin and might be related to the development of the Neoproterozoic basin at the eastern margin of the East European Craton. The eastern part of the Yamantau anticlinorium was exhumed below 200 °C in the Late Carboniferous or Early Permian. The diagenetic grade of the autochthonous Palaeozoic sedimentary units increases toward the stack of Palaeozoic nappes and might partly be caused by the deformational process due to the emplacement of the Palaeozoic nappes. Within the Timirovo thrust sheet, the decrease of metamorphic grade with stratigraphic age developed prior to the emplacement of the nappes. The upper anchizonal metamorphic grade of the Upper Devonian slates of the Zilair nappe results from the deformation process related to the Lower Carboniferous nappe emplacement. 相似文献