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1.
In Mexico, the Upper Jurassic to lowermost Cretaceous La Casita and coeval La Caja and La Pimienta formations are well-known for their abundant and well-preserved marine vertebrates and invertebrates. The latter include conspicuous inoceramid bivalves of the genus Anopaea not formally described previously from Mexico. Anopaea bassei (Lecolle de Cantú, 1967), Anopaea cf. stoliczkai (Holdhaus, 1913), Anopaea cf. callistoensis Crame and Kelly, 1995 and Anopaea sp. are rare constituents in distinctive Tithonian–lower Berriasian levels of the La Caja Formation and one Tithonian horizon of the La Pimienta Formation. Anopaea bassei was previously documented from the Tithonian of central Mexico and Cuba, while most other members of Anopaea described here are only known from southern high latitudes. The Mexican assemblage also includes taxa which closely resemble Anopaea stoliczkai from the Tithonian of India, Indonesia and the Antarctic Peninsula, and Anopaea callistoensis from the late Tithonian to ?early Berriasian of the Antarctic Peninsula. Our new data expand the palaeogeographical distribution of the high latitude Anopaea to the Gulf of Mexico region and substantiate faunal exchange, in the Late Jurassic–earliest Cretaceous, between Mexico and the Antarctic Realm.  相似文献   

2.
The coal-bearing, alternating marine and non-marine Longzhaogou Group in eastern Heilongjiang, northeastern China, has long been considered as Jurassic, or mainly Jurassic, in age. However, recent studies have demonstrated that the ammonites and dinoflagellate cysts are of Early Cretaceous age. This has now been confirmed by new radiolarian evidence. The radiolarian fauna recovered from the upper Qihulin Formation of the Longzhaogou Group consists of nine poorly preserved species referable to nine genera. Novixitus is a Cretaceous genus, and the specimens of Archaeodictyomitra sp. and Xitus sp. recovered resemble A. vulgaris Pessagno and X. spicularius (Aliev), respectively.  相似文献   

3.
The Mino tectono-stratigraphic terrane, central Japan, underlain by Permian to Jurassic sedimentary and volcanic rocks of various origins, was formed through accretion processes associated with the Mesozoic sea-floor spreading. This conclusion has been reached mainly from the following reasoning:
1. (1) the entire boundary of this terrane is defined by tectonic belts with high-pressure metamorphic rocks and serpentinized ultramafic rocks,
2. (2) the chemistry and petrology of the Permian greenstones demonstrate their affinity with abyssal tholeiitic and alkalic basalts,
3. (3) the widespread, but chaotic, occurrence of Permian greenstones, Triassic cherts, and Jurassic siliceous shales in the younger Jurassic clastic rocks of this terrane suggests extensive post-depositional mixing of strata,
4. (4) the sedimentology of the Jurassic sandstones strongly suggests that they are turbidity-current deposits supplied from cratonic lands,
5. (5) the South-Pacific type fossil assemblage in the Mino terrane shows strong contrast with the North-Pacific type fossil assemblage of the adjacent terranes,
6. (6) the paleomagnetism of the Permian and Jurassic greenstones, the Triassic cherts, and the Jurassic siliceous shales implies long-distance northward drift in Cretaceous time of these rocks from their original low latitudinal regions.
Along with this northward migration, the Mino terrane was accreted with extensive internal deformation to northeast Asia including the present Hida terrane. Recent accumulation of paleomagnetic and paleontologic data in the Pacific peripheral regions appears to support the existence of many allochthonous terranes which migrated from the equatorial regions. The Mino terane may be regarded as one example of these Circum-Pacific allochthons.  相似文献   

4.
The Karoo Supergroup outcropst in the mid-Zambezi Valley, southern Zambia. It is underlain by the Sinakumbe Group of Ordovician to Devonian age. The Lower Karoo Group (Late Carboniferous to Permian age) consists of the basal Siankondobo Sandstone Formation, which comprises three facies, overlain by the Gwembe Coal Formation with its economically important coal deposits, in turn overlain by the Madumabisa Mudstone Formation which consists of lacustrine mudstone, calcilutite, sandstone, and concretionary calcareous beds. The Upper Karoo Group (Triassic to Early Jurassic) is sub-divided into the coarsely arenaceous Escarpment Grit, overlain by the fining upwards Interbedded Sandstone and Mudstone, Red Sandstone; and Batoka Basalt Formations.Palynomorph assemblages suggest that the Siankondobo Sandstone Formation is Late Carboniferous (Gzhelian) to Early Permian (Asselian to Early Sakmarian) in age, the Gwembe Coal Formation Early Permian (Artinskian to Kungurian), the Madumabisa Mudstone Late Permian (Tatarian), and the Interbedded Sandstone and Mudstone Early or Middle Triassic (Late Scythian or Anisian). The marked quantitative variations in the assemblages are due partly to age differences, but they also reflect vegetational differences resulting from different paleoclimates and different facies.The low thermal maturity of the formations (Thermal Alteration Index 2) suggests that the rocks are oil prone. However, the general scarcity of amorphous kerogen, such as the alga Botryococcus sp., and the low proportion of exinous material, indicates a low potential for liquid hydrocarbons. Gas may have been generated, particularly in the coal seams of the Gwembe Coal Formation, that are more deeply buried.  相似文献   

5.
在我国西南南盘江地区广泛分布着二叠系生物礁。可分为两种类型:1)堤礁;2)孤立礁。前者一般沿碳酸盐台地的边缘分布,后者发育于盆地内孤立碳酸盐台地的边缘。广南生物礁的礁后灰岩由浅灰色块状骨架岩组成。造架生物以串管海绵、纤维海绵、tabulozoans等为主,往往有蓝绿藻包覆。骨架生物之间有极为发育的纤状方解石胶结物。本文共描述了串管海绵8属12种,它们是Waagenella salinaria irregalaris Zhang,Waagenella sp., Rhabdactinita of columnaria Yabe and Sugiyama, Rhabdactinia sp., Intrasporeocoelia hubeiensis Fan and Zhang,Intrasporeocoelia sp., Uvanella guangnanensis sp. nov., Girtycoelia sp., Colospongia of dubia Laube, Colospongta sp., Verticillites sp.,Lichuanospongta typica Zhang.  相似文献   

6.
Among the smaller foraminifers from the Lower Permian of Western Tethys (Pamir, Northern Afghanistan, Central and Eastern Iran, Armenia, and Turkey), foraminiferal assemblages characteristic of the Asselian, Sakmarian, Yakhtashian, Bolorian, and Kubergandian stages are distinguished. The first stratigraphic scheme based on smaller foraminifers is elaborated for the Lower Permian (Cisuralian Series) of Western Tethys. Eight biostratigraphic units distinguished in the Lower Permian and one in the Kubergandian Stage are ranked as beds with characteristic foraminiferal assemblages. At particular stratigraphic levels, the beds are recognizable in different paleogeographic provinces of the Tethyan Realm, which enables correlation between deposits concurrently accumulated under dissimilar climatic and facies conditions to be carried. Some of the distinguished beds are recognizable beyond the Tethyan Realm, for instance in the Donetsk basin, Cis-Urals, Pechora coal basin, and Spitsbergen. Among foraminifers that have been studied, 264 species and subspecies, including 16 new taxa, are identified. The following species and subspecies are identified and described for the first time: Hemigordius permicus beitepicus subsp. nov., H. pamiricus sp. nov., Neohemigordius afganicus sp. nov., N. carnicus sp. nov., N. bangi sp. nov., N. zulumarticus sp. nov., N. kubergandinicus sp. nov., Geinitzina grandella sp. nov., G. dentiformis sp. nov., G. bella sp. nov., Pachyphloia paraovata minima sp. nov., P. aucta sp. nov., Frondicularia porrecta sp. nov., Globivalvulina gigantea sp. nov., G. compacta sp. nov., and G. explicata sp. nov.  相似文献   

7.
Heterogenous megaspores recovered from the Upper Permian sediments of Kuraloi Area, Ib-River coalfield, have been systematically described. The megaspore assemblage includes seven genera with seventeen species viz. Bokarosporites rotundus, Banksisporites indicus, B. utkalensis, Biharisporites spinosus, Biharisporites sp.A, Biharisporites sp.B, Jhariatriletes baculosus, J. srivastavae, J. damudicus, Manumisporites distinctus, Singhisporites baculatus, S. radialis, S. surangei, Ramispinatispora indica, R. nautiyalii and Ramispinatispora sp. Additionally, a new species of Ramispinatispora viz. R.mahanadiensis has been identified. Associated spore pollen assemblages are suggestive of a Late Permian age corresponding to Raniganj/Kamthi Formation. Raniganj megaspores are known from Damodar and Godavari Basins. The newly recorded megaspore assemblage from the Ib-River coalfield is comparable to that of Raniganj/Kamthi Formation of Godavari Graben. The diversity in exosporium ornamentations indicates structural diversity. Moreover, their prolific presence ultimately points towards occurrence of heterosporous source vegetation in the area.  相似文献   

8.
The Iranian part of the Kopet Dagh Basin is located in north-eastern Iran, where sedimentation was continuous throughout Jurassic to Tertiary times. The ammonite content of the Sanganeh Formation (Lower Cretaceous) has been studied. The following parahoplitid forms have been recorded: Acanthohoplites cf. aschiltaensis, A. cf. bigoureti, A. sp. 1, A. sp. 2, A. spp., Colombiceras sp., Hypacanthoplites cf. anglicus, H. cf. clavatus, H. cf. elegans, H. cf. subrectangulatus, H. uhligi, H. sp., Parahoplites cf. campichii and P. cf. maximus.  相似文献   

9.
Two new species of wasps belonging to the family Ephialtitidae,Praeproapocritusflexus sp.nov.and Proapocritus parallelus sp.nov.,from the Middle Jurassic Jiulongshan Formation of southeastern Inner Mongolia,China,are described and illustrated.Praeproapocritus vulgates Rasnitsyn & Zhang,2010 and six species of Proapocritus,P.densipediculus,P.sculptus,P.longantennatus,P.formosus,P.atropus,and P.elegans,all described by Rasnitsyn and Zhang in 2010,are first record from the Middle Jurassic of China.These two new findings supplement the morphological understanding of ephialtitids in the Middle Jurassic of China and broaden the diversity of ephialtitids in their by-gone ecosystems.  相似文献   

10.
<正>The classification and phytogeny of the basal Vespina(=Orussoidea+Apocrita)are reconsidered based primarily on rich and well preserved material from the Middle Jurassic of Daohugou in Inner Mongolia,China. Comparatively smooth morphological transitions are traced from a Xiphydriidae-like ancestor toward Orussoidea via the Jurassic family Karatavitidae,and through Karatavitidae and the Jurassic and Early Cretaceous family Ephialtitidae independently to Stephanidae,to Evanioidea,and,via the extinct Jurassic Kuafuidae fam.nov.to the remaining Apocrita.New hypothesis is proposed concerning development of the characteristic wasp-waist of Apocrita,which is supposed to appear independently and in different ways in Evanioidea and in the rest of Apocrita.As a result,six infraorders are proposed for the suborder Vespina with the following taxonomic structure:infraorder Orussomorpha including the only superfamily Orussoidea(Karatavitidae+Paroryssidae + Orussidae),infraorder Stephanomorpha with the only superfamily Stephanoidea(Ephialtitidae+Stephanidae), infraorder Evaniomorpha with the only superfamily Evanioidea of traditional composition,infraorder Ceraphronomorpha with the superfamilies Ceraphronoidea s.str.and monotypical Megalyroidea and Trigonaloidea,and the infraorders Proctotrupomorpha,Ichneumonomorpha,and Vespomorpha of traditional composition.The family Kuafuidae is unplaced to infraorder because it is putatively paraphyletic with respect to Ceraphronomorpha,Proctotrupomorpha,Ichneumonomorpha and Vespomorpha.Described as new are Karatavites junfengi sp.nov,Praeratavites wuhuaensis sp.nov.,P.perspicuus sp.nov.,Postxiphydria daohugouensis gen.et sp.nov.,P.ningchengensis gen.et sp.nov.,Postxiphydroides strenuus gen.et sp.nov.,Praeratavitoides amabilis gen.et sp.nov.,Proapocrtius densipediculus sp.nov.,P.sculptus sp.nov.,P.longantennatus sp.nov., P.formosus sp.nov.,P.atropus sp.nov.,P.elegans sp.nov.,Stephanogaster pristinus sp.nov.,Asiephialtites lini sp. nov.,Praeproapocritus vulgatus gen.et sp.nov.,Sinaulacogastrinus solidus gen.et sp.nov.,Sinevania speciosa gen. et sp.nov.,Eonevania robusta gen.et sp.nov.,Kuafua polyneura gen.et sp.nov.(all from the Middle Jurassic of Daohugou),as well as Kuafuidae fam.nov.including Kuafua gen.nov.as well as Arthrogaster Rasnitsyn,1975,and Leptogastrella Rasnitsyn,1975 from the Upper Jurassic of Karatau in Kazakhstan.  相似文献   

11.
Detrital zircon U–Pb LAM-ICPMS age patterns for sandstones from the mid-Permian –Triassic part (Rakaia Terrane) of the accretionary wedge forming the Torlesse Composite Terrane in Otago, New Zealand, and from the early Permian Nambucca Block of the New England Orogen, eastern Australia, constrain the development of the early Gondwana margin. In Otago, the Triassic Torlesse samples have a major (64%), younger group of Permian–Early Triassic age components at ca 280, 255 and 240 Ma, and a minor (30%) older age group with a Precambrian–early Paleozoic range (ca 1000, 600 and 500 Ma). In Permian sandstones nearby, the younger, Late Permian age components are diminished (30%) with respect to the older Precambrian–early Paleozoic age group, which now also contains major (50%) and unusual Carboniferous age components at ca 350–330 Ma. Sandstones from the Nambucca Block, an early Permian extensional basin in the southern New England Orogen, follow the Torlesse pattern: the youngest. Early Permian age components are minor (<20%) and the overall age patterns are dominated (40%) by Carboniferous age components (ca 350–320 Ma). These latter zircons are inherited from either the adjacent Devonian–Carboniferous accretionary wedge (e.g. Texas-Woolomin and Coffs Harbour Blocks) or the forearc basin (Tamworth Belt) farther to the west, in which volcaniclastic-dominated sandstone units have very similar pre-Permian (principally Carboniferous) age components. This gradual variation in age patterns from Devonian–late Carboniferous time in Australia to Late Permian–mid-Cretaceous time in New Zealand suggests an evolutionary model for the Eastern Gondwanaland plate margin and the repositioning of its subduction zone. (1) A Devonian to Carboniferous accretionary wedge in the New England Orogen developing at a (present-day) Queensland position until late in the Carboniferous. (2) Early Permian outboard repositioning of the primary, magmatic arc allowing formation of extensional basins throughout the New England Orogen. (3) Early to mid-Permian translocation of the accretionary wedge and more inboard active-margin elements, southwards to their present position. This was accompanied by oroclinal bending which allowed the initiation of a new, late Permian to Early Triassic accretionary wedge (eventually the Torlesse Composite Terrane of New Zealand) in an offshore Queensland position. (4) Jurassic–Cretaceous development of this accretionary wedge offshore, in northern Zealandia, with southwards translation of the various constituent terranes of the Torlesse Composite Terrane to their present New Zealand position.  相似文献   

12.
Three new species of the extinct genus of Eoptychopterina from the Eoptychopteridae  相似文献   

13.
在1:50000广顺幅区调过程中,首次发现广顺地区下二叠统粱山组有大量丰富的遗迹化石存在。本文特作以报道,并为该区早二叠世古环境分析提供了新的地质资料。一、广顺地区梁山组简介梁山组为早二叠世栖霞早期的沉积地层。它与下伏地层上石炭统马平组(主要由亮晶生物屑灰岩、团粒灰岩组成)呈不整合接触;与上覆下二叠统栖霞组(由泥—细晶生物屑灰岩夹钙质页岩、泥灰岩、燧石灰岩组成)呈整合接触。梁山组主要由石英砂岩、页岩和粘土岩组成,也见有生物屑硅质岩。有较多的腕足类和  相似文献   

14.
鄂西利川晚二叠世生物礁的纤维海绵和Tabulozoan   总被引:2,自引:0,他引:2       下载免费PDF全文
范嘉松  张维 《地质科学》1987,(4):326-333
箭囊海绵(Pharetronida)目可分为两个亚目:(1)串管海绵;(2)纤维海绵。纤维海绵骨骼是由骨纤构成,在骨纤内的海绵骨针由于重结晶作用而消失贻尽,但仍能识别出一些骨针的形态。Tabulozoan暂归入硬海绵内。本文描述的纤维海绵有以下各属:Peronidella sp., Peronidella sp.nov., Stellispongia sp.,对Tabulozoan也进行了描述和讨论。  相似文献   

15.
An Early Permian small ammonoid fauna consisting of Neocrimites sp., Agathiceras suessi Gemmellaro, A. girtyi Böse, Agathiceras? sp., and Miklukhoceras sp. was found in nodules of a fine sandstone bed exposed in the Phatthalung-Hat Yai area of southern peninsular Thailand. The ammonoid-bearing bed belongs stratigraphically to the uppermost part of the Kaeng Krachan Group, which is essentially a clastic-dominant, Late Carboniferous (?) to Early Permian stratigraphic unit, widely distributed in western and peninsular Thailand. This ammonoid fauna is considered to be of Bolorian (Kungurian) age and includes Agathiceras girtyi Böse, which is described for the first time from Thailand. The present discovery of Bolorian ammonoids suggests that the uppermost part of the Kaeng Krachan Group is slightly younger than previously considered and around the latest Early Permian. This further implies that the continental margin environment of the Sibumasu Block drastically changed at around Bolorian time from a cool, clastic-dominant shelf condition to a temperate to subtropical, carbonate platform due to rapid northward drift after middle Artinskian rifting.  相似文献   

16.
吉林省吉中地区二叠系岩石地层单位“一拉溪组”为原长春地质学院吉林区测队在1960年创立。《吉林省岩石地层》(1997)等明确为不采用之单位,《中国地层典二叠系》(2000)等标明为采用地层单位。已有的实际材料证明:在“一拉溪组”建组剖面——九台市波泥河子“一拉溪组”剖面的灰、黑色粉砂岩中发现Neocalamites、Eguisetites、Citenis、Ginkgoites及Cladophlebis为主的早侏罗世植物群;原认为在范家屯组建组剖面,该组假整合于范家屯组之上,现又在该剖面上部(10层以上)发现4个产植物化石的层位,15层除产植物Pecopterissp.(P.cf.anthriscifolia)、Phyllothecacf.deliguescens、Paracalamitestenuicostata、Noeggerathhiopsissp.等外,还见有淡水叶肢介Cyclotoguzitessp.,确证“一拉溪组”系不整合于杨家沟组之上。因此,作为二叠系岩石地层单位的“一拉溪组”已不可能为了优先权而加以保留。但在统一研究该区中生代岩石地层序列时,一拉溪组和其他单位一样,可按优先权法则参与竞选。  相似文献   

17.
The history of investigation of the common Jurassic and Cretaceous genus Pseudotorellia Florin (Ginkgoales) represented by needle-shaped, narrow linear or lanceolate leaves bearing several veins and characterized by a single type of epidermis, is considered. An extended diagnosis of the genus and its taxonomic composition with regard to the epidermal characters are reported; the stratigraphic and geographical range of its species and the genus evolution are refined. Three new species Pseudotorellia asiatica N. Nosova et Kiritchkova, sp. nov., P. ketoviana N. Nosova et Kiritchkova, sp. nov., and P. samylinae N. Nosova et Kiritchkova, sp. nov. described from the Lower Jurassic (Toarcian) sediments, are proposed as the correlative taxa within the Caspian oil and gas province. The stratotype and reference sections of the Lower Jurassic sediments in the Mangyshlak Mountains are reported for the first time.  相似文献   

18.
Well-preserved Ginkgo pollen organs are analyzed from the Middle Jurassic Xishanyao Formation of the Turpan–Hami Basin, Xinjiang Uygur Autonomous Region, northwestern China, and are described as a new species, Ginkgo hamiensis Z.X. Wang et B.N. Sun sp. nov. The immature male cones are cylindrical and catkin-like, with two longitudinal stripes on the stalk. The pollen sacs are shaped like a long oval with two pollen sacs fused together for each microsporophyll, and the microsporophyll tip is a triangular cystidium. The pollen grains are oblong or fusiform and monocolpate; both ends are blunt or sharp. By comparison with previously reported fossil records of Ginkgo plants, we determined that the current fossils are different from all other reported species; thus, the present fossil is referred to as a new species of Ginkgo. The reproductive organs of the Ginkgo fossils described herein can provide valuable information for the study of Ginkgo plants. Further, there are two probable evolutionary trends in the Ginkgo pollen cones. One trend is that the number of pollen sacs changed from three or four during the Jurassic and Cretaceous to two at the present day; the other is that the number of pollen sacs has remained two from the Middle Jurassic to the present day. In addition, the pollen cones described herein are similar to the pollen cones of the extant Ginkgo, which strongly indicates that the morphology of Ginkgo plants may have remained highly conserved over millions of years.  相似文献   

19.
Two new genera and species of fossil Palaeontinidae are described from Daohugou Village, Inner Mongolia, China: Cladocossus undulatus gen. et sp. nov. and Cricocossus paradoxus gen. et sp. nov. Both new genera are described based on well-preserved forewings. This discovery confirms the high diversity of palaeontinids during the Middle Jurassic. Both specimens have interesting modal structures which are new to Palaeontinidae: M five-branched and M3 with two branches. Based on this character, wing structural characteristic is discussed.  相似文献   

20.
In the Murihiku Terrane of New Zealand, U-Pb detrital zircon ages in Murihiku Supergroup sandstones of Late Triassic, Jurassic and possibly earliest Cretaceous age have a marked youngest age component that is close to, and sometimes coincident with, established biostratigraphic ages, thus reflecting contemporary volcanism. However, youngest Huriwai Group samples yield 137–142 Ma zircon age components (earliest Early Cretaceous) in conflict with palynofloras that suggest only a latest Jurassic age. This is resolved if the age of the Jurassic/Cretaceous boundary is lowered to ca. 140 Ma. Older, reworked zircons are mainly Early Jurassic, Late Triassic and Late Permian reflecting an enduring exhumed magmatic arc source nearby. This might be in the adjacent Median Batholith but as a Murihiku sediment source its Jurassic, Triassic and Permian elements are not well-matched in terms of extent, age and bulk compositions. A connection between the Murihiku (proximal forearc) and Waipapa Composite (distal accretionary wedge) terranes is probable, with a common magmatic arc, speculatively situated in the New England Orogen, eastern Australia.  相似文献   

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