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1.
A first palynostratigraphic scheme of Upper Triassic deposits in northern Switzerland was established based on spore-pollen associations and dinoflagellate cyst records from the upper part of the Upper Triassic Klettgau Formation and the lower part of the Lower Jurassic Staffelegg Formation. Drill cores from the Adlerberg region (Basel Tabular Jura) and from Weiach (northern part of Canton Zurich) as well as from an outcrop at the Chilchzimmersattel (Basel Folded Jura) were studied and five informal palynological associations are distinguished. These palynological associations correlate with palynological association of the Central European Epicontinental Basin and the Tethyan realm and provide a stratigraphic framework for the uppermost Triassic sediments in northern Switzerland. Throughout the uppermost Triassic to Jurassic palynological succession a remarkable prominence of Classopollis spp. is observed. Besides Classopollis spp. the three Rhaetian palynological associations A to C from the Upper Triassic Belchen Member include typical Rhaetian spore-pollen and dinoflagellate taxa (e.g., Rhaetipollis germanicus, Geopollis zwolinskae, Rhaetogonyaulax rhaetica, and Dapcodinium priscum). Association B differs from association A in a higher relative abundance of the sporomorph taxa Perinopollenites spp. and the consistent occurrence of Granuloperculatipollis rudis and Ricciisporites tuberculatus. Spore diversity is highest in the late Rhaetian palynological association C and includes Polypodiisporites polymicroforatus. A Rhaetian age for the Belchen Member is confirmed by palynological associations A–C, but there is no record of the latest Rhaetian and the earliest Jurassic. In contrast to the Rhaetian palynological associations the Early Jurassic associations W and D include Pinuspollenites spp., Trachysporites fuscus (in association W), and Ischyosporites variegatus. In the view of the end-Triassic mass extinction and contemporaneous environmental changes the described palynofloral succession represents the pre-extinction phase (associations A and B) including a distinct transgression, the extinction phase (association C) associated with a regression, and the post-extinction phase (association W).  相似文献   

2.
The coal-bearing sequences of Barakar and Raniganj formations exposed in Bina and Jhingurdah open-cast collieries, respectively, are analysed for their macro- and miofloral content. The sediment successions primarily comprise of sandstones, shales, claystones and coal seams. In addition to the diverse glossopterid assemblage, four palynoassemblage zones, namely Zones I and II in Bina Colliery and Zones III and IV in Jhingurdah Colliery, have also been recorded in the present study. The megafossil assemblage from the Barakar strata of Bina Colliery comprises of three genera, namely Gangamopteris, Glossopteris and cf. Noeggerathiopsis. Palynoassemblage-I is characterised by the dominance of non-striate bisaccate pollen genus Scheuringipollenites and subdominance of striate bisaccate Faunipollenites and infers these strata to be of Early Permian (Artinskian) age (Lower Barakar Formation). The palynoassemblage has also yielded a large number of naked fossil spore tetrads, which is the first record of spore tetrads from any Artinskian strata in the world and has a significant bearing on the climatic conditions. The palynoassemblage-II is characterised with the dominance of Faunipollenites over Scheuringipollenites and is indicative of Kungurian age (Upper Barakar Formation). The megafossil assemblage from the Raniganj Formation of Jhingurdah Colliery comprises of five genera with 26 species representing four orders, viz., Equisetales, Cordaitales, Cycadales and Glossopteridales. The order Glossopteridales is highly diversified with 23 taxa and the genus Glossopteris, with 22 species, dominates the flora. The mioflora of this colliery is represented by two distinct palynoassemblages. The palynoassemblage-III is correlatable with the palynoflora of Early Permian (Artinskian) Lower Barakar Formation. The assemblage suggests the continuity of older biozones into the younger ones. The palynoassemblage-IV equates the beds with composition V: Striatopodocarpites–Faunipollenites–Gondisporites assemblage zone of Tiwari and Tripathi (1992) of Late Permian (Lopingian) Raniganj Formation in Damodar Basin. The FAD’s of Alisporites, Klausipollenites, Falcisporites, Arcuatipollenites pellucidus and Playfordiaspora cancellosa palynotaxa in this assemblage enhance the end Permian level of the Jhingurdah Top seam, as these elements are the key species to mark the transition of Permian into the Lower Triassic.  相似文献   

3.
The present work deals with the palaeoenvironment and depositional setting of the subsurface sediments from bore hole RT-4 of Tamra block from Raniganj coalfield of Damodar Basin, India. Nineteen shale samples were subjected to palynological and coal petrographical analyses. On the basis of botanical affinity between the miospores and the parent plants as well as the different plant groups, each coal plant assemblage was determined. The dominance of bisaccates such as Scheuringipollenites, Faunipollenites (=Protohaploxypinus), Striatopodocarpites and presence of monosaccates such as Densipollenites, Parasaccites reflect a peat forming community composed mainly of gymnosperms. Subordinate trilete spores derived from filicopsids (Cyclogranisporites, Horriditriletes, Brevitirletes, Callumispora, Microbaculsispora, Microfoveolatispora, Cyclobaculisporites), lycopsids (Indotriradites, Gondispoirtes and Didecitriletes) and sphenopsids (Laevigatosporites ) are less abundant occurring in variable proportions reflecting a hypautocthonous taphocenose. Presence of Botryococccus algae has been recorded. Palynofacies and petrographic analyses suggest deposition in open mires in a Limnic to limno-telmatic conditions with intermittent flooding of the site.  相似文献   

4.
Outcropped of the Kuhbanan Formation at Dahu, near Zarand, about 63 km north of Kerman, Iran contains peri-Gondwana trilobites. In this study, 185 trilobite samples including six species and genera were identified and described from Dahu section. This trilobite’s assemblage including Redlichia noetlingi, Redlichia sp., Kermanella kuhbananensis, Kermanella lata lata, Kermanella lata minuta, Iranoleesia pisiformis, and Iranaspis sp. based on occurrence of the trilobite fauna a late Early to Middle Cambrian (Series 2–3) is suggested for this strata. These trilobite fauna help confirm conclusions from recent geological studies that place the Kerman Basin of Iran during the Cambrian.  相似文献   

5.
Palynological and petrological studies have been undertaken on the Gondwana coal and associated lithologies encountered in borehole EBM-2 of East Bokaro coalfield of Damodar Basin, India. The palynological investigation resulted in the recognition of Assemblage–III (Densipollenites, 27.9 m–214.30 m), Assemblage–II (Striatopodocarpites + Faunipollenites, 225.00 m–297.60 m) and Assemblage–I (Faunipollenites + Scheuringipollenites, 307.00m–433.00 m). Lithofacies study was also done for better understanding of the preservation and abundance/paucity of the spores and pollen in different lithologies as the current borehole has significant thickness of mudstones, shales and siltstone. Palynofacies study and Petrographical studies of coal samples encountered in the borehole were used to determine the depositional environment of the coal precursor peat swamp. Palynological data has revealed the presence of younger Raniganj palynoflora between 27.00-214.30 m depth that is lithologically defined as Barren Measures Formation. This spore pollen study has proved that these sediments were deposited during late early Permian to late Permian period. Further the maceral analysis of organic sediments as well as the Thermal Alteration Index (TAI) has revealed that the coaly shale at 336.5 m depth has hydrocarbon generation potential.  相似文献   

6.
Rhizomes with tubers of Equisetum cf. oppositum Ma, Su et Zhang are described for the first time from the Paleocene-Eocene of North Nima Basin, the Tibet Autonomous Region, southwestern China. The fossils are preserved as rows of 6 tubers and rhizome consisting of distinct node and internodes; the tubers are elliptical, ovate, and more or less rounded with distinct longitudinal ribs and grooves on the surface of internodes. According to the similarity of the morphology and arrangement with fossil Equisetum subgenus Equisetum, the present fossils are assigned to Equisetum cf. oppositum Ma, Su et Zhang. Vegetative reproduction and energy storage are the main two functions of tubers, and the presence of tubers implies that burial occurred during the late fall or winter. Based on the occurrence of fossil Equisetum in the forth sequence and the ichthyolite in Nima Basin, associated with zoolite, fossil plant, and palynological assemblages in Lunpola Basin, it would suggest a locally warm, wet environment, probably a lacustrine depositional environment during the Paleocene-Eocene in the Nima Basin of geographic center of Tibetan Plateau. Furthermore, the molasse characteristic of Niubao Formation shows that the Nima Basin situated in the hinterland of Tibetan Plateau might uplifted during the Paleocene-Eocene and have become land from sea. The study is of great significance for further interpretation of the history of uplift in the Paleocene-Eocene of the Tibetan Plateau.  相似文献   

7.
The Vendian (Ediacaran) beds of the Zavkhan Basin, in the upper part of the Tsagaanolom Formation (<632 ± 14 Ma), yielded a new “Zavkhan” association of algae, microfossils, and problematic organisms, which is established in the series of alternating chert-carbonate shale with phosphorite interbeds. This association is distinct in the predomination of large (250 μm and over) sphaeromorphic microfossils of the genera Tasmanites, Archaeooides, and Leiosphaeridia, whereas acanthomorph acritarchs are represented by rarely found Cavaspina sp. and Tanarium sp. Multicellular algae included fragments of encrusting or foliate thalli with pseudoparenchymatous structure of polygonal cells characteristic of Rhodophyta algae (Thallophycoides sp.), and cordlike thalli of Vendotaenid algae Tyrasotaenia podolica. These layers of siltstone contain imprints of the problematic Vendian macrofossil Beltanelliformis brunsae. In their stratigraphic position, chemostratigraphic data, and fossil assemblage, the “Zavkhan” association can be assigned to the Upper Vendian.  相似文献   

8.
Neotrocholina Reichel, 1956 is one of the most important benthic foraminifera in Early Cretaceous. Some of the species of this genus are indexes in biostratigraphy especially for this interval (e.g., Neotrocholina friburgensis: Late Barremian–Early Aptian; Neotrocholina aptiensis: Early Aptian). In order to conduct accurate paleontological investigations, sampling from the carbonate units of the Tirgan Formation in Kopet Dagh sedimentary basin is done. According to the occurrence level in the studied stratigraphic sections as well as biometric interpretations, two species of this genus (N. friburgensis and Neotrocholina valdensis) are pointed out.  相似文献   

9.
The present megafloral assemblage recorded from the Barakar sediments of Dholpahar section along Singda rivulet near Gopal Prasad Village in Talcher Basin comprises of equisetaceous stems, Gangamopteris buriadica, Palaeovittaria kurzii and 19 species of the genus Glossopteris. Record of Gangamopteris, Palaeovittaria and many narrow mesh forms of Glosspteris viz., G. angustifolia, G. churiensis, G. communis, G. recurva, G. spatulata, G. stenoneura, G. tenuifolia, G. vulgaris and G. zeilleri from two older fossiliferous horizons demonstrates that these fossils were preserved during Lower Barakar sedimentation. The report of middle and broad mesh forms of Glossopteris viz., G. barakarensis, G. browniana, G. indica, G. intermittens, G. karharbariensis, G. nakkarea, G. oldhamii, G. taeniensis and G. retifera in the youngest fossiliferous horizons reveals that these fossils were preserved during the deposition of Upper Barakar sediments. The continuation of some of the Karharbari plant fossils in the early phase of Barakar Formation and their disappearance in the flora of Late Barakar suggests a shift in the climatic setup. Palaeoclimate and palaeovegetation of this area are also summarised in this study. Moreover, the fossil assemblages of different fossiliferous beds of Dholpahar section demonstrate the evolution of midrib and meshes in different reticulate leaves.  相似文献   

10.
The microfossil assemblages of subsurface Carboniferous rocks from Faghur-1x were examined and identified. Their biostratigraphical and paleoenvironmental importance were investigated. The assemblage included well-preserved foraminifera like Omphalotis omphalota, Omphalotis sp. 2, Omphalotis sp. 3, Paraarchaediscus stilus, Paraarchaediscus koktjubensis, Archaediscus krestovnikovi, Archaediscus complanatus, Archaediscus inflatus, Archaediscus karreri, Diplosphearina inequalis, Eotubertina sp., Tetrataxis conica, Cribrostomum lecomptei, Palaeotextularia angulata, and Palaeotextularia longiseptata. This foraminiferal association indicates the late Viséan-early Serpukhovian. The other microfossils are gastropods, brachiopods, ostracods, crinoidal ossicles, frond-like fenestrate bryozoan types and stick-like colonies, echinoderms, microproblematica like Draffania biloba and algal Calcisphaera and the dasyclad Koninckopora. This microfossils assemblage points to the deposition in a restricted to open platform in a lagoonal framework environment. The Tehenu Basin is the eastern segment of northern African Sahara basins that provided refuge for the foraminiferal genera through the mass extinction events during the glacial Viséan-Serpukhovian times. However, its foraminiferal associations have lower diversities than the western basins, which indicate that it was more readily affected by the mass extinction event.  相似文献   

11.
The Jahrum Formation (Upper Paleocene to Middle Eocene) is composed of carbonate and dolomitic carbonate rocks in the Zagros Basin. The Zagros is located at the boundary between the Arabian and Eurasian lithosphere plates and represent the orogenic response to a collision between Eurasia and advancing Arabia during the Cenozoic. The study area is located in the northern part of Kuh-E-Tudej, ~175 km southeast of Shiraz in the Folded Zagros Zone. The Jahrum Formation at Kuh-E-Tudej, with a thickness of 190 m, consists of medium to massive bedded limestone. The following foraminiferal index species are identified in the studied section: Fallotella alavensis, Kathina sp., Miscellanea sp., Lockhartia sp.,Orbitolites shirazeinsis, Nummulites sp., Opertorbitolites sp., Dictyoconus cf. egyptiensis, Orbitolites cf. complanatus, Dictyoconus sp., Coskinolina sp., Somalina stefaninii, Discocyclina sp., Praerhapydionina sp., Coskinolina cf. liburnica, Nummulites cf. globulus, Nummulites cf. aturicus, and Alveolina sp. The age of the studied sediments ranges from Upper Paleocene to Middle Eocene. The microbiostratigraphic studies revealed four biozones based on the foraminifers identified in the studied section.  相似文献   

12.
In the Rajmahal Basin Lower Cretaceous rocks are classified under the Rajmahal Formation. It includes a series of volcanic basalt flows and associated sedimentary intertrappean beds. Up to 15 basalt flows have been recorded in this basin. The intertrappean beds comprise sandstone, shale, siltstone, and clay deposits which are rich in spores and pollen. The palynoflora recovered from intertrappean beds shows definite pattern of evolution and diversification. On the basis of its overall composition, distribution pattern of age marker taxa and the First Appearance Datum of key taxa, four palynological assemblages have been identified. The chronology of these assemblages in ascending order is (1) Ruffordiaspora australiensis, (2) Foraminisporis wonthaggiensis, (3) Foraminisporis asymmetricus, and (4) Coptospora verrucosa. These assemblages ascertain the age of the volcano-sedimentary sequence of the Rajmahal Formation in the Rajmahal Basin as Berriasian to Aptian. The palynochronology of the intertrappean beds enables their correlation in the Rajmahal Basin. In different areas of the basin, the palynological dating of the lowermost intertrappean bed within the Rajmahal Formation which overlies the Dubrajpur Formation, has provided a Berriasian to Aptian age. The palynological assemblage indicating the Berriasian age is inferred as the time of the initiation of volcanic activity which continued up to the Aptian in the Rajmahal Basin.  相似文献   

13.
The Jurassic successions represent a wide distribution in North of the Kerman province. These successions include Ab-Haji, Badamu, and Hojedk formations. The Hojedk Formation contains the plant fossils. The Lenjan section is one of the suitable areas for paleontological studies on the Hojedk Formation. The study section is mostly composed of green sandstone and shale with several interbedded coal veins with different thicknesses. The thickness of the Hojedk Formation is about 200 m in the Lenjan section. In this study, seven genera and 13 species of macro plant fossils were identified and described, including Nilssonia undulata, Nilssonia bozorga, Nilssonia berriesi, Nilssonia sp., Klukia cf. exilis, Klukia exilis, Cladophlebis antarctica, Coniopteris lobata, Coniopteris murrayana, Elatocladus confertus, Podozamites sp., Equisetites sp., and Coniopteris sp. The Bajocian–Bathonian can be attributed to the Lenjan section based on the recognized flora.  相似文献   

14.
Smaller foraminifers from Upper Yakhtashian and Bolorian deposits of the stratotype area (Pamir, Darvaz, Tajikistan) are investigated. Four assemblages are defined. The first assemblage is from Chalaroschwagerina vulgaris-Pamirina darvasica Zone. The second assemblage found in the transitional Yakhtashian-Bolorian beds includes Globivalvulina, Palaeotextulariidae, Hemigordiidae, and Glomospira, associated with the first Pachyphloia and Langella forms. Characteristic taxa of third assemblage from the Misellina (Brevaxina) dyhrenfurthi Zone are Geinitzinidae, Globivalvulina, Palaeotextulariidae, Glomospira, and rare Pachyphloia. The forth assemblage of Hemigordiidae, Pachyphloia, Palaeotextulariidae, Geinitzinidae, Pseudoagathammina is identified in the M. (Misellina) parvicostata Zone. The assemblages were compared with concurrent analogs from China, Japan, and Russia. New species and subspecies Glomospira paleograndis sp. nov., G. darvasica sp. nov., Agathammina darvasica sp. nov., Pachyphloia darvasica sp. nov., Nodosinelloides cubanicus elongatus subsp. nov., and Hemigordius saranensis darvasicus subsp. nov. are described.  相似文献   

15.
Petrographic thin section analysis of the samples collected from the type section of Neil West Coast Formation, situated in the west coast of Neil Island yielded moderately preserved coralline red algae, benthic and planktic foraminifers, coral fragments, echinoid spines and gastropod shells. The coralline red algae are represented by both non-geniculate and geniculate forms. The non-geniculate forms belong to melobesids, lithophylloids and mastophoroides. The geniculate forms are represented by species of Amphiroa, Corallina, and Jania. However, the diversity and abundance of coralline algal forms are less in comparison to the benthic foraminifers those are represented by Amphistegina, Neorotalia, Ammonia, Elphidium, Operculina, Assilina, Amphisorus and texularids. Planktic foraminifers like Globigerinoides and other biogenic components viz., gastropod shells, echinoid spines and coral fragments are also common. A foraminiferal-algal grainstone facies has been recognized as observed in the field as well as in thin section analysis. The overall assemblage of the biogenic components and facies analysis indicate intertidal to near shore environment of deposition with high energy condition and increased hydrodynamic activity.  相似文献   

16.
The age of the marine Nodular Limestone Formation of the Bagh Group is refined at Substage level through ammonoid and inoceramid index taxa. The study is based on the fresh collections from three well-defined successive intervals (Lower Karondia, Upper Karondia and Chirakhan members) of this formation having excellent exposures in different localities of the Narmada Basin, central India. The first record of the widely distributed Turonian ammonoid genera Spathites Kummel and Decker and Collignoniceras Breistroffer from the Nodular Limestone Formation constrained its age exclusively to Turonian. The Early Turonian species Spathites (Jeanrogericeras) aff. revelieranus (Courtiller) and Mytiloides labiatus (Sclotheim) occur in the lower part, while the Middle Turonian marker Collignoniceras cf. carolinum (d’Obrbigny) and Inoceramus hobetsensis (Nagao and Matsumoto) occurs in the upper part of the Karondia Member. The record of the index species Inoceramus teshioensis (Nagao and Matsumoto) in association with Placenticeras mintoi Vredenburg from Chirakhan Member allows a definite Late Turonian age. The present contribution is an attempt to resolve the controversies in the age of the Nodular Limestone Formation and also demarcation of the three divisions (Early, Middle and Late) of the Turonian Stage in the Narmada Basin, central India.  相似文献   

17.
Continental (fluvial) strata of the Pinjor Formation (Siwalik Group), northwestern Himalayas, India, contain an invertebrate trace fossil assemblage containing Planolites beverleyensis, Palaeophycus isp., Scoyenia gracilis, Taenidium barretti and other undifferentiated traces. The traces are found in an \(\sim \)26 m thick interval of alternating pinkish red siltstone, which is intercalated with mudstone, and thickly-bedded buff and greenish coloured sandstone. These sediments are interpreted as the deposits of floodplains and channel-bars of fluvial environments and low-energy overbank floodplain deposits. The trace fossils studied here are the first well documented ichnofossil assemblage from the vast, late Cenozoic Siwalik depositional system. They are not only of palaeoenvironmental significance, but they add to the growing ichnofossil database in facies of fluvial origin and should be an impetus to further ichnological studies of the Siwalik Group.  相似文献   

18.
A comparative morphological analysis is performed for 13 valid dinocyst species of genus Vesperopsis. Their distribution over Eurasia and North America in the Hauterivian–Cenomanian is traced and the characteristics of these deposits are given. Three species of the most stratigraphically significant dinocysts are distinguished: V. fragilis for the Upper Hauterivian of Western Siberia and V. mayi and V. longicornis for the Aptian of East Greenland. Analysis of facies confinement of the dinocysts Vesperopsis made it possible to group species of the considered genus over conditionally preferable paleosettings. Continental facies (freshwater, brackish-water) are characterized by species V. yanjiensis, V. glabra, V. sanjiensis, and V. jixianensis, while V. zhaodongensiis, V. didaoensis, and V. dolabella are typical of the coastal–marine facies, and V. digitatа, V. nebulosa, and V. mayi are typical of marine facies.  相似文献   

19.
The present paper examines the coralline algal assemblage recovered from the Holocene sediments of Agatti Island, Lakshadweep, India. The assemblage comprises nine species of coralline algae which include Amphiroa fragilisma, Lithophyllum nitorum, Lithophyllum incrustans, Lithoporella melobesioids, Spongites sp., Porolithon craspedium, Aethesolithon problematicum, Clathromorphum parcum, Melobesoideae gen. et spec. indet. Clathromorphum parcumis an endophytic coralline alga reported for the first time from the Indian subcontinent. Out of these, seven species belong to the family Corallinaceae and the two represent the family Hapalidiaceae of the class Rhodophyceae. Coralline algal association of this area is dominated by Lithophylloideae, Melobesioideae and Mastophoroideae which include encrusting to fragmented growth forms. The associated branching corals are well developed and adapted to shallow, warm water, low turbid, protected lagoonal environment.  相似文献   

20.
A rich assemblage of palynomorphs including miospores and megaspores has been recorded from the bore core no. IBKAN-2 drilled at a depth of 17.80m in Kuraloi Block-A, south-west part of the Ib-River Coalfield, Jharsuguda district, Odisha. The miofloral assemblage recovered shows prominence of cingulate, zonate, taeniate, non-striate and non saccate palynotaxa which indicate an early Triassic age and is comparable with the palynoassemblages of the same age known from the Damodar basin, India. The megaspore assemblage includes eight genera and fifteen species namely, Banksisporites karanpuraensis, B. indicus, B. utkalensis, Banksisporites sp., Barakarella pantii, Barakarella sp., Biharisporites spinosus, Biharisporites sp., Erlansonisporites triassicus, Erlansonisporites cf. erlansonii, Erlansonisporites sp. Jhariatriletes sp., Singhisporites sp., Ramispinatispora sp. and Talchirella trivedii. Records of megaspores are sparse in the early Triassic of Gondwana basins of India. The present study records the first occurrence of miospores and megaspores from the early Triassic of Mahanadi basin besides substantiating the earlier data.  相似文献   

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