Tectonic Setting and Nature of the Provenance of Sedimentary Rocks in Lanping Mesozoic- Cenozoic Basin： Evidence from Geochemistry of Sandstones

The geochemical composition of sandstones in the sedimentary basin is controlled mainly by the tectonic setting of the provenance, and it is therefore possible to reveal the tectonic setting of the provenance and the nature of source rocks in terms of the geochemical composition of sandstones. The major elements, rare-earth dements and trace elements of the Mesozoic-Cenozoic sandstones in the Lanping Basin are studied in this paper, revealing that the tectonic settings of the provenance for Mesozoic-Cenozoic sedimentary rocks in the Lanping Basin belong to a passive continental margin and a continental island arc. Combined with the data on sedimentary facies and palaeogeography, it is referred that the eastern part of the basin is located mainly at the tectonic setting of the passive continental margin before Mesozoic, whereas the western part may be represented by a continental island arc. This is compatible with the regional geology data. The protoliths of sedimentary rocks should be derived from the upper continental crust, and are composed mainly of felsic rocks, mixed with some andesitic rocks and old sediment components. Therefore, the Lanping Mesozoic-Cenozoic Basin is a typical continental-type basin. This provides strong geochemical evidence for the evolution of the paleo-Tethys and theb asin-range transition.     

Discovery of Late Jurassic Sporopollen Assemblage from the Tamulangou Formation in the Hongqi Sag of the Hailar Basin, Inner Mongolia, China

<正>Objective The Hailar Basin is situated in the northwestern margin of the Jiamusi-Mongolia Block. It was a continent marginal basin to the south of the Mongolia-Okhotsk Ocean during the Jurassic and Cretaceous. The basement of the basin is a late Paleozoic marine deposit. The filling of the basin is characterized by terrestrial volcanic rocks,     

The Pre-Sinian Basement and Mineralization on the Western Margin of the Yangtze Paraplatform

The pre-Sinian basement on the southwestern margin of the Yangtze paraplatform consists of threemetamorphic rock series of different ages. Being products of different tectonic events and environments, theydiffer markedly in original rock sequences, metamorphism. tectonic style and characteristics of granitoids andmineral deposits. The Late Archean Kangdian cration mainly comprises the Kangding and Julin Groups with ametamorphic age of nearly 2500 Ma. They are supracrustal rocks dominated by mafic volcanics enclosed introndhjemitic rocks The craton is believed to represent a granite-greenstone terrane of Late Archaean age.There occur mineral deposits such as graphite and kyanite deposits of metamorphic origin, muscovite depositsin pegmatites and gold quartz veins in gneissic granites, banded hornblende-magnetite mineralization and cop-per and zinc mineralizations related to felsic volcanics. Large V-Ti-bearing magnetite deposits were also formedin the mafic. ultramafic stratiform intrusions emplaced on the margins of the craton during the MiddleProterozoic. Copper and nickel deposits are found in several ultramafic intrusions. Extending in a north-southdirection, the Proterozoic mobile belt consists mainly of the Early Proterozoic Hekou Group and MiddleProterozoic Huili and Kunyang Groups. and they are thought to be accumulations in a Proterozoic rift troughor aulacogen. During the Early Proterozoic, the rift trough was characterized by intense volcanism and pres-ence of iron ore deposits of volcano-magmatic type, iron-copper deposits of exhalative-sedimentary type. TheMid-Late Proterozoic of the rift trough mainly witnessed the formation of sedimentary stratiform copper de-posits and submarine sedimentary iron deposits. In the wake of the emplacement of the Jinningian andChengjiangian granites in the Late Proterozoic, skarn-type tin and tin-iron ore deposits were formed.     

http://www.sciencedirect.com/science/article/pii/S1674987113000558

Several stratigraphic breaks and unconformities exist in the Mesoproterozoic successions in the northern margin of the North China Block.Geologic characters and spatial distributions of fve of these unconformities,which have resulted from different geological processes,have been studied.The unconformity beneath the Dahongyu Formation is interpreted as a breakup unconformity,representing the time of transition from continental rift to passive continental margin.The unconformities beneath the Gaoyuzhuang and the Yangzhuang formations are considered to be the consequence of regional eustatic fuctuations,leading to the exposure of highlands in passive margins during low sea-level stands and transgressive deposition on coastal regions during high sea-level stands.The unconformity atop the Tieling Formation might be caused by uplift due to contractional deformation in a back-arc setting,whereas the uplift after the deposition of the Xiamaling Formation might be attributed to a continental collision event.It is assumed that the occurrences of these unconformities in the Mesoproterozoic successions in the northern margin of the North China Block had a close bearing on the assemblage and breakup of the Columbia and Rodinia supercontinents.     

The Late Palaeozoic Rifting on Hainan Island, China

There occurred rifting on Hainan Island in the Late Palaeozoic. Bimodal volcanic rocks composed ofbasalt and rhyolite developed in the Carboniferous. Widespread in the Late Palaeozoic formations are severallayers of fluvial intermontane conglomerates whose distribution is controlled by rift faults. The Late Palaeozoicdeposits dominaled by clastic rocks are, for a major part, of marine facies and of continental facies in the lowerand upper parts. Lithological and lithochemical studies indicate that the detrital rocks were formed in atectonic setting of continental rifting. The evolution of the rifting terminated at the stage of transition form anintra continental rift to an intercontinental one and the rift basin was a bay opening westward to the sea.     

Geochemistry of the Paleocene Clastic Rocks in Lishui Sag, East China Sea Shelf Basin: Implications for Tectonic Background and Provenance

The Lishui Sag, in the East China Sea Shelf Basin, is rich in hydrocarbons, with the major hydrocarbon-bearing layers being the Paleocene Mingyuefeng clastic rocks. Analysis of the implicit geologic background information of these Paleocene clastic rocks using petrological and geochemical methods has significant practical importance. These Paleocene sandstones are mainly lithic arenite, lithic arkose and greywacke, composed of K-feldspar, plagioclase, authigenic clays, silica and carbonates. As continental deposits, Yueguifeng clastic rocks have high aluminosilicate and mafic detritus contents, while the Lingfeng and Mingyuefeng Formations are rich in silica due to an oscillating coastal marine depositional environment. The major element contents of these Paleocene sandstones are low and have a concentrated distribution, indicating that the geochemical composition is non-epigenetic, transformed by sedimentary processes and diagenesis. The Yueguifeng detritus comprises recycled sediments, controlled by moderate weathering and erosion, while the Lingfeng and Mingyuefeng detritus is interpreted as primarily first-cycle materials due to low chemical weathering. In the Late Cretaceous to Early Paleocene, the Pacific Plate began subducting under the Eurasian Plate, causing an orogeny by plate collision and magma eruption due to the melting of subducted oceanic crust. This resulted in the dual tectonic settings of “active margin” and “continental island arc” in the East China Sea Shelf Basin. During the Late Paleocene, the Pacific Plate margin migrated eastward along with development of the Philippine Ocean Plate, and the tectonic setting of the Lishui Sag gradually turned into a passive continental margin. Detrital sources included both orogenic continental blocks and continental island arcs, and the parent rocks are primarily felsic volcanic rocks and granites.     

The Confirmation of the Neoproterozoic Langshan Group in Inner Mongolia and Its Significance

<正>There is a large Mesoproterozoic rift at the northern margin of North China Craton(NCC),and one of China’s most important metallogenic belts,the Langshan-Zhaertai Shan-Bayan Obo mesoproterozoic metallogenic belt is just located in this rift.This metallogenic belt contains some large or ultra-large ore deposits,such as the Bayan Obo iron deposits and ultra-large rare earth deposits,and the large Dongshengmiao Cu-Pb-Zn sulphide deposits.The Zhaertai Group is composed of a set of metamorphic rocks,interbedded with thin ferruginous     

New Zircon U-Pb Ages of the Granodiorites in the Southern Great Xing’an Range and their Tectonic Implications

The Southern Great Xing'an Range,Northeast China,is located in the eastern part of the Central Asian Orogenic Belt.It is considered to be one of the most important metallogenic belts,commonly hosting a series of skarn.porphyry and magmatic hydrothermal Pb-Zn-Ag-Cu Mo-Sn polymetallic deposits(Fig.1).Complex tectonic events have occurred in this region,including the closure of the Palco-Asian Ocean in the Late Palaeozoic,the opening and closure of the Mongol Okhotsk Ocean and the subduction of the Paleo-Pacific Ocean in the Mesozoic.     

Cenozoic Sea‐land Transition and its Petroleum Geological Significance in the Northern South China Sea

The process of Cenozoic sea-land changes in the northern South China Sea(SCS)controlled the sedimentary filling pattern and played an important role in the petroleum geological characteristics of the northern marginal sedimentary basins.Under the control of the opening process of the SCS,the northern SCS Cenozoic transgression generally showed the characteristics of early in the east and late in the west,and early in the south and late in the north.The initial transgression occurred in the Eocene in the Taixinan Basin(TXNB)of the eastern SCS,while the transgression occurred until the Pliocene in the Yinggehai Basin(YGHB)of the western SCS.International Ocean Discovery Program(IODP)expeditions(Expeditions 367/368)revealed that the initial transgression of the SCS basin occurred at approximately 34 Ma,which was the initial opening time of the SCS.The period of drastic changes in the sedimentary environment caused by large-scale transgression corresponded to the opening time of the southwestern subbasin(approximately 23 Ma),which also represented the peak of the spreading of the SCS.The sea-land transition process controls the distribution of alternating continent-marine facies,marine facies source rocks and reservoirs in the basins.The marine facies source rocks of the basins in the northern SCS have a trend of gradually becoming younger from east to west,which is consistent with the regional process of gradual transgression from east to west.Regional sea-level changes were comprehensively influenced by SCS opening and global sea-level changes.These processes led to the early development in the east and south and late development in the west and north for the carbonate platform in the SCS.Carbonate platforms form another type of"selfgenerating and self-accumulating"oil-gas reservoir in the northern SCS.The sea-land transition controlled the depositional filling patterns of different basins and laid the foundation of marine deposits for oil and gas resources.The source-reservoircap assemblage in the northern SCS was controlled horizontally by provenance supply and sedimentary environmental changes caused by sea-land transition and vertically by the tectonic evolution of the SCS and regional sea-level changes.     

Reworking Intensity—A Key Factor Leading to the Formation of Superlarge Gold Deposits in Greenstone Belts and Metamorphosed Microclastic Rocks in China

The greenstone belt and metamorphosed microclastic rock-type superlarge gold deposits in China are hosted in metamorphic rocks and later intrusive bodies.Sedimentation.regional metamorphism and mineralization contributed a lot to the formation of the deposits,so did remelting magmatic process to some deposits,but the deposits were finally formed by reworking processes.The key factor leading to the formation of superlarge gold deposits is the reworking intensity,which for superlarge gold deposits is reflected by the large-scale reworked source rocks and even ore materials of various sources,strongly oxidized ore-forming fluids with a long and repeated active history and stable geothermal heat current.The factor which decides the reworking intensity is the network consisting of structures of different classes.     

A review of the stratigraphy and geological setting of the Palaeoproterozoic Magondi Supergroup,Zimbabwe – Type locality for the Lomagundi carbon isotope excursion

The Palaeoproterozoic Magondi Supergroup lies unconformably on the Archaean granitoid-greenstone terrain of the Zimbabwe Craton and experienced deformation and metamorphism at 2.06–1.96 Ga to form the Magondi Mobile Belt. The Magondi Supergroup comprises three lithostratigraphic units. Volcano-sedimentary rift deposits (Deweras Group) are unconformably overlain by passive margin, back-arc, and foreland basin sedimentary successions, including shallow-marine sedimentary rocks (Lomagundi Group) in the east, and deeper-water shelf to continental slope deposits in the west (Piriwiri Group). Based on the upward-coarsening trend and presence of volcanic rocks at the top of the Piriwiri and Lomagundi groups, the Piriwiri Group is considered to be a distal, deeper-water time-equivalent of the Lomagundi Group. The Magondi Supergroup experienced low-grade metamorphism in the southeastern zone, but the grade increases to upper greenschist and amphibolite facies grade to the north along strike and, more dramatically, across strike to the west, reaching upper amphibolite to granulite facies in the Piriwiri Group.     

Stratigraphic and tectonic settings of Proterozoic glaciogenic rocks and banded iron-formations: relevance to the snowball Earth debate

Among Palaeoproterozoic glacial deposits on four continents, the best preserved and documented are in the Huronian on the north shore of Lake Huron, Ontario, where three glaciogenic formations have been recognized. The youngest is the Gowganda Formation. The glacial deposits of the Gowganda Formation were deposited on a newly formed passive margin. To the west, on the south side of Lake Superior, the oldest Palaeoproterozoic succession (Chocolay Group) begins with glaciogenic diamictites that have been correlated with the Gowganda Formation. The >2.2 Ga passive margin succession (Chocolay Group=upper Huronian) is overlain, with profound unconformity, by a >1.88 Ga succession that includes the superior-type banded iron-formations (BIFs). The iron-formations are therefore not genetically associated with Palaeoproterozoic glaciation but were deposited 300 Ma later in a basin that formed as a result of closure of the “Huronian” ocean. In Western Australia, Palaeoproterozoic glaciogenic deposits of the Meteorite Bore Member appear to have formed part of a similar basin fill. The glaciogenic rocks are, however, separated from underlying BIF by a thick siliciclastic succession. In both North America and Western Australia, BIF-deposition took place in compressional (possibly foreland basin) settings but the iron-formations are of greatly different age, suggesting that the most significant control on their formation was not oxygenation of the Earth’s atmosphere but rather, emplacement of Fe-rich waters (uplifted as a result of ocean floor destruction?) in a siliciclastic-starved environment where oxidation (biogenic?) could take place. Some of the Australian BIFs appear to predate the appearance of red beds in North American Palaeoproterozoic successions and are therefore unlikely to be related to oxygenation of the atmosphere.Neoproterozoic glaciogenic deposits are widespread on the world’s continents. Some are associated with iron-formations. Two theories have emerged to explain these enigmatic BIFs. According to the snowball Earth hypothesis (SEH), ice-covered oceans would have permitted buildup of dissolved Fe. Precipitation of Fe-rich sediments would have taken place following reoxygenation of the hydrosphere as the ice cover disappeared. A second theory involves glaciation of Red Sea rift-type basins. Fe-charged brines in such basins would have precipitated on being mixed with “normal” seawater as a result of glacially driven thermal overturn. Both theories provide an explanation of the hydrothermal imprint on the geochemistry of Neoproterozoic BIF but the restricted development of BIF (relative to glacial deposits), evidence of rift activity such as significant facies and thickness changes, and association with volcanic rocks, all favour deposition in a rift environment.Cap carbonates are one of the cornerstones of the SEH. Escape from the snowball condition is said to have resulted from buildup of atmospheric CO₂ while the weathering cycle was stopped. Under such conditions, the first siliciclastic deposits following glaciation, should be extremely weathered, and should be overlain by sedimentary rocks that show a gradual return to more “normal” compositions. Using a chemical index of alteration (CIA) it can be shown that, in the case of the Gowganda Formation, the CIA shows a gradual upward increase, opposite to that predicted by the SEH. The Earth underwent severe climatic perturbations both near the beginning and end of the Proterozoic Eon but whether it attained a totally frozen surface condition (as postulated under the SEH) remains speculative.     

胶辽地块古元古代沉积组合：年代与层序

根据变质岩石组合、成矿特征等方面对比研究，证明胶辽地块古元古代粉子山群、北部辽河群、老岭群可对比，荆山群和南部辽河群、集安群亦可以比，相应的北部和南部变质地层为同时异相。通过对各群同位素年代学资料的收集总结，表明它们沉积于2．5至1．9Ga期间，变质作用起始于2．2Ga，终止于正．6Ga。以辽河群为例，各岩组的原岩恢复及沉积环境讨论，表明整个裂陷带经历了从裂谷盆地向被动大陆边缘转化。最后于该活动带南缘转变为活动大陆边缘的，反映了该活动带完整的层序沉积环境变迁过程。     

Age constraints on the Palaeoproterozoic Lomagundi–Jatuli Event in Zimbabwe: Zircon geochronology of the Magondi Supergroup

The ca. 2.2–2.1 Ga Magondi Supergroup on the Zimbabwe Craton in Southern Africa is mainly composed of sedimentary rocks deposited in a rift basin/passive continental margin, which record a unique episode in carbon isotope perturbation called the Lomagundi–Jatuli Event (LJE). This study reports new U–Pb ages of detrital zircons from the Deweras and Lomagundi groups of the Magondi Supergroup, and of igneous zircons from underlying granitoids, to constrain the timing of the LJE and to identify the provenance of the Magondi Supergroup. Most analysed detrital zircon grains range in ages between ca. 2.9 and 2.6 Ga. Three ca. 2.3–2.2 Ga detrital zircons from sandstone of the Deweras Group, with the youngest ²⁰⁷Pb‐²⁰⁶Pb age of 2,216 ± 22 Ma, indicate the onset of LJE in the Zimbabwe Craton was almost simultaneous to that in Fennoscandia and the Superior Craton, supporting the global synchronicity of the LJE.     

Chemostratigraphy of Paleoproterozoic carbonate successions of the Wyoming Craton: tectonic forcing of biogeochemical change?

The Archean Wyoming Craton is flanked on the south and east by belts of Paleoproterozoic supracrustal successions whose correlation is complicated by lack of geochronologic constraints and continuous outcrop. However, carbonate units in these successions may be correlated by integrating carbon isotope stratigraphy with lithostratigraphy. The 10 km thick Paleoproterozoic Snowy Pass Supergroup in the Medicine Bow Mountains was deposited on the present-day southern flank of the Wyoming Craton; it contains three discrete levels of glacial diamictite correlative with those in the Huronian Supergroup, on the southern margin of the Superior Craton. The Nash Fork Formation of the upper Snowy Pass Supergroup is significantly younger than the uppermost diamictite and was deposited after the end of the Paleoproterozoic glacial epoch. Carbonates at the base of the Nash Fork Formation record remarkable ¹³C-enrichment, up to +28‰ (V-PDB), whereas those from overlying members of the lower Nash Fork Formation have δ¹³C values between +6 and +8‰. Carbonates from the upper Nash Fork Formation above the carbonaceous shale have carbon isotope values ranging between 0 and +2.5‰. The transition from high carbon isotope values to those near 0‰ in the Nash Fork Formation is similar to that at the end of the ca. 2.2–2.1 Ga carbon isotope excursion in Fennoscandia. This chemostratigraphic trend and deposition of BIFs, Mn-rich lithologies, carbonaceous shales and phosphorites at the end of the global ca. 2.2–2.1 Ga carbon isotope excursion are likely related to ocean overturn associated with the final breakup of the Kenorland supercontinent. Correlative carbonates from the Slaughterhouse Formation in the Sierra Madre, WY, and from the Whalen Group in the Rawhide Creek area in the Hartville Uplift, WY, have highly positive carbon isotope values. In contrast, carbonates from other exposures of the Whalen Group in the Hartville Uplift and all carbonate units in the Black Hills, SD, have carbon isotope values close to 0‰. Combined with existing geochronologic and stratigraphic constraints, these data suggest that the Slaughterhouse Formation and the succession exposed in the Rawhide Creek area of the Hartville Uplift are correlative with the lower and middle Nash Fork Formation and were deposited during the ca. 2.2–2.1 Ga carbon isotope excursion. The Estes and Roberts Draw formations in the Black Hills and carbonates from other exposures in the Hartville Uplift postdate the ca. 2.2–2.1 Ga positive carbon isotope excursion and are most likely correlative with the upper Nash Fork Formation. The passive margin, on which the carbonates with highly positive carbon isotope values were deposited, extended around the southern flank of the Wyoming Craton through the Sierra Madre, Medicine Bow Mountains and Hartville Uplift. The presence of carbonates with carbon isotope values close to 0‰ in the upper Nash Fork Formation and the Whalen Group indicates that the passive margin persisted on the southern flank of the Wyoming Craton after the carbon isotope excursion. Rifting in the Black Hills, likely related to the final breakup of the Kenorland, succeeded the carbon isotope excursion, since the Estes and Roberts Draw formations, deposited during rifting and ocean opening on the eastern flank of the Wyoming Craton, postdate the carbon isotope excursion.     

鄂尔多斯盆地晚古生代沉积岩源区构造背景及物源分析

鄂尔多斯盆地周缘物源均来自上地壳,以长英质岩石为主,主要为太古宇、元古宇的各类变火山-沉积岩组成的古老变质岩系,同时具有一定量的花岗岩和碱性玄武岩的混合,但物源成分及南北源区构造背景有所差异。在常量元素及稀土元素组成上,盆地南北物源区的沉积岩在地区及层位之间存在差异,且该变化符合大洋岛弧→大陆岛弧→活动大陆边缘→被动大陆边缘常量元素、稀土元素以及负Eu异常的变化趋势。常量元素变化分析表明盆地北部物源主要来自板块俯冲碰撞地带,与被动大陆边缘环境和活动大陆边缘环境相关,少数为与活动大陆边缘相关的岛弧构造环境有关,到晚古生代中晚期才逐渐与被动大陆边缘环境和活动大陆边缘环境相关。稀土元素对比分析表明,盆地北部物源与太古宙、元古宙的花岗片麻岩、闪长片麻岩、二长花岗岩、变余岩屑砂岩及千枚岩具有亲源性;而盆地南部早—中二叠世长期受被动大陆边缘物源影响,具有高SiO2,低Na2O的特征,这与太古宙—元古宙的太华群、秦岭群、宽坪群等岩系的高SiO2含量,K2O/Na2O>1的特征一致,到晚古生代后期,逐渐与活动大陆边缘物源相关。北秦岭晚古生代山间盆地具有快速混杂堆积的沉积特点,属于盆地外缘,并与鄂尔多斯盆地呈连续过渡的状况,物源上具有继承关系;盆地晚古生代沉积岩中Gd含量及(Gd/Yb)N比值具有随时间迁移的特征,分析表明北部物源区在太原期处于构造快速活动期,而南部物源从山西期才开始进入快速活动期,这与区域构造演化背景一致,即北部物源区抬升要早于南部。     

南海东北部珠江口盆地成生演化与油气运聚成藏规律

珠江口盆地处在南海东北部准被动大陆边缘的特殊大地构造位置,其区域背景及油气地质条件复杂。该区不仅具有中国东部新生代陆相断陷盆地的基本特征,亦具本身的特殊性。由于盆地不同区带油气地质条件的差异,故具有明显的"北油南气"分布规律及纵向上多种资源叠置共生与复合的特点:北部裂陷带及东沙隆起浅水区,处于减薄的洋陆过渡型地壳靠近陆缘一侧,其古近系断陷规模及半地堑洼陷沉积充填规模均比相邻的南部裂陷带深水区小,且地温梯度低、大地热流小,烃源岩有机质热演化处在油窗范围,以产大量石油为主伴有少量油型气,构成了以文昌、恩平、西江、惠州及陆丰油田群和流花油田群为主的北部浅水油气富集区。该区具有上渐新统三角洲砂岩及中新统礁灰岩外源型油气运聚成藏机制及含油气系统;南部裂陷带及南部隆起周缘深水区,以邻近深水区的白云凹陷北坡—番禺低隆起中小气田群和白云凹陷东部深水区LW3-1、LH34-2及LH29-1等天然气藏为代表,构成了以天然气为主但亦具石油及水合物资源潜力的深水油气富集区。由于南部裂陷带深水区处在洋陆过渡型地壳靠近洋壳一侧,地壳薄而裂陷深、断陷规模大,其与北部浅水区相比多了一套上渐新统海相烃源岩。该区地温梯度及大地热流偏高,烃源岩多处在成熟-高熟凝析油及湿气阶段,以产大量天然气及少量轻质油和凝析油为主,具有上渐新统陆架边缘三角洲砂岩和中新统深水扇混源型天然气运聚成藏机制及含油气系统。油气纵向分布具有深水海底天然气水合物及浅层气/生物气与深部常规油气共生叠置的关系。     

华北陆块基底构造格局及早期大陆克拉通化过程

依据区域构造分析及同位素年代娄数据库,华北克拉通普质基底主要可以区划为以处构造单元：１）鄂尔多斯陆块新太古代被动边缘沉积;２）恒山－－承德太古代末期构造带;３）太古代末期五台－－登封岛弧带杂岩及构造缝合带;４）鲁西－－冀东－辽吉新太古代活动大陆边缘岩浆杂岩带;５）胶辽陆块;６）冀北－－固阳古元代初造山带及内蒙－＝东再造麻粒岩要带;７）吕梁－－中条古元古代裂谷带;８）辽南古元古代裂谷带。华北克拉通早     

南美坎波斯盆地构造演化特征及构造活动对油气成藏条件的影响

为探讨构造活动对南美坎波斯盆地油气成藏条件的影响,从盆地形成的动力学背景、不同演化阶段的构造沉积作用,不同层系的生储盖发育特征及其与构造作用的关系出发,剖析了坎波斯盆地在其演化过程中各种构造活动对生油层、储层、盖层、圈闭、运移通道以及油气保存条件等方面的控制作用。结果表明: Tristan地幔柱隆升是引起南大西洋伸展、裂开与南美板块右时针旋转的动力来源; Tristan热点产生的Rio Grande-Walvis洋脊和由南往北剪刀式裂开,是包括坎波斯盆地在内的南大西洋中段盆地在陆内裂谷和陆间裂谷阶段封闭环境以及被动大陆边缘盆地早期阶段半封闭环境的主因,为裂谷层系优质烃源岩和过渡层系蒸发岩和漂移层系下部海相烃源岩的形成提供了条件; 坎波斯盆地裂谷期断裂活动形成地堑、半地堑和掀斜断块,控制了盐下烃源岩、微生物碳酸盐岩储层和盐下圈闭的分布,过渡层系盐岩活动和盐底辟作用控制了盐下油气系统盐岩盖层的分布、盐下-盐上的油气运移通道形成和盐上浊积岩储层的展布。这些内在关系的揭示对被动大陆边缘油气成藏规律和控制因素分析以及油气勘探部署都有重要的参考价值。     

The Rhenohercynian passive margin of SW England: Development,inversion and extensional reactivation

The SW England Rhenohercynian passive margin initiated with rift-related non-marine sedimentation and bimodal magmatism (Late Lockhovian). Continued lithospheric extension resulted in the exhumation of mantle peridotites and limited seafloor spreading (Emsian-Eifelian). Variscan convergence commenced during the Late Eifelian and was coeval with rifting further north. Collision was marked by the Early Carboniferous emergence of deep marine sedimentary/volcanic rocks from the distal continental margin, oceanic lithosphere, pre-rift basement and upper plate gneisses (correlated with the Mid-German Crystalline High of the Saxothuringian Zone). Progressive inversion of the passive margin was strongly influenced by rift basin geometry. Convergence ceased in the Late Carboniferous and was replaced by an extensional regime that reactivated basin controlling/thrust faults and reorientated earlier fabrics (Start-Perranporth Zone). The resultant exhumation of the lower plate was accompanied by emplacement of the Early Permian SW England granites and was contemporaneous with upper plate sedimentary basin formation above the reactivated Rhenohercynian suture. The Rhenohercynian passive margin probably developed in a marginal basin north of the Rheic Ocean or, possibly, a successor basin following its closure. The Lizard ophiolite is unlikely to represent Rheic Ocean floor or associated forearc (SSZ) crust. The Rheic and Rhenohercynian sutures may be coincident or the Rheic suture may be located further south in the Léon Domain.