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1.
The Cretaceous System in China   总被引:5,自引:0,他引:5       下载免费PDF全文
This paper provides an outline of Cretaceous stratigraphy and paleogeography in China, which is based on rich data obtained from recent researches. Cretaceous deposits are widespread in China. Most strata are of nonmarine origin and marine sediments occur only in Tibet, western Tarim Basin of Xinjiang, Taiwan and limited localities of eastern Heilongjiang. All deposits are rich in fossils and well-constrained biostratigraphically. The stratigraphic successions of different regions are illustrated, and general stratigraphic division and correlation have been introduced. The marine deposits are described in the Tibetan Tethys, Kashi-Hotan Region of Xinjiang, eastern Heilongjiang, western Yunnan and Taiwan; the nonmarine deposits are outlined from northeast China, southeast China, southern interior China, southwest China, the Shaanxi-Gansu-Ningxia region, and northwestern China intermontane basins. The sedimentary facies and paleogeography are diversified. In Tibet the basin evolution is largely related to the subduction and collision of the Indian Plate against the Eurasian Continent, and shows a tectonic evolution in the Cretaceous. Foraminifera are a dominant biota in the Tibet Tethys. Nonmarine sediments include variegated and red beds, coal- or salt-bearing horizons, and volcanic rocks. These deposits contain diverse and abundant continental faunas and floras, as well as important coal and oil resources. The Cretaceous stratigraphy and paleogeography in China have presented a foundation for geological studies.  相似文献   

2.
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   

3.
The Songliao basin (SB) is a superposed basin with two different kinds of basin fills. The lower one is characterized by a fault-bounded volcanogenic succession comprising of intercalated volcanic, pyroclastic and epiclastic rocks. The volcanic rocks, dating from 110 Ma to 130 Ma, are of geochemically active continental margin type. Fast northward migration of the SB block occurred during the major episodes of the volcanism inferred from their paleomagnetic information. The upper one of the basin fill is dominated by non-marine sag-style sedimentary sequence of siliciclastics and minor carbonates. The basin center shifted westwards from the early to late Cretaceous revealed by the GGT seismic velocity structure suggesting dynamic change in the basin evolution. Thus, a superposed basin model is proposed. Evolution of the SB involves three periods including (1) Alptian and pre-Aptian: a retroarc basin and range system of Andes type related to Mongolia-Okhotsk collisional belt (MOCB); (2) Albian to Companian: a sag-like strike-slip basin under transtension related to oblique subduction of the Pacific plate along the eastern margin of the Eurasian plate; (3) since Maastrichtian: a tectonic inverse basin under compression related to normal subduction of the Pacific plate under the Eurasian plate, characterized by overthrust, westward migration of the depocenter and eastward uplifting of the basin margin.  相似文献   

4.
In this paper. it is demonstrated that there exist marine horizons in the upper part of the lower subcycleand the upper subeycle of the Kizilsu Group in Xinjiang. based on new evidence of authigenic glauconite.boron content. carbon and oxygen stablc isotopic analyses. and lithological and sedimentary features. The up-per part of the lower subeycle is the lowermost marine horizon of the Cretaceous in the western Tarim Basin,which is inferred to be of Barremian age.  相似文献   

5.
Some of the best records of continental vertebrates from the Cretaceous of Europe come from Romania, particularly two well-known occurrences of dwarfed and morphologically aberrant dinosaurs and other taxa that lived on islands (the Cornet and Haţeg Island faunas). Substantially less is known about those vertebrates living in the more stable, cratonic regions of Romania (and Eastern Europe as a whole), particularly during the earliest Cretaceous. We describe one of the few early Early Cretaceous fossils that have ever been found from these regions, the tooth of a large theropod dinosaur from Southern Dobrogea, which was discovered over a century ago but whose age and identification have been controversial. We identify the specimen as coming from the Valanginian stage of the Early Cretaceous, an incredibly poorly sampled interval in global dinosaur evolution, and as belonging to Carcharodontosauridae, a clade of derived, large-bodied apex predators whose earliest Cretaceous history is poorly known. Quantitative analyses demonstrate that the Romanian tooth shows affinities with a derived carcharodontosaurid subgroup, the Carcharodontosaurinae, which until now has been known solely from Gondwana. Our results suggest that this subgroup of colossal predators did not evolve vicariantly as Laurasia split from Gondwana, but originated earlier, perhaps in Europe. The carcharodontosaurine diversification may have been tied to a north-to-south trans-Tethyan dispersal that took place sometime between the Valanginian and the Aptian, illustrating the importance of palaeogeographic ties between these two realms during the largely mysterious early–mid Early Cretaceous.  相似文献   

6.
The western part of the Tarim Basin in Xinjiang is one of the main areas in China where the marineCretaceous is well developed. The Upper Cretaceous Yingjisha Group represented mainly by sediments of lit-toral, near-shore neritic and estuarine facies is divided in ascending order into the Kukebai Formation, theOytak Formation, the Ygezya Formation and the Tuylouk Formation. For about thirty years, the basal beds of the Kukebai Formation had been considered to be the lowermostmarine horizon of the Cretaceous in the western part of the Tarim Basin, which represents the earliest trans-gression of the Cretaceous Sea into this region. Recently. marine trace fossils, Ophiomorpha nodosa, O.tuberosa and Thalassinoides? spp. were found in abundance and fine preservation from the upper subcycle andupper part of the lower subcycle of the Kezlesu Group underlying the Kukebai Formation. The fact indicatesthat the marine transgression there took place earlier than the Kukebaian. Process of transgression and regression and change of environment in the West Tarim Basin during the pe-riod from the late Early Cretaceous to the end of the Cretaceous is also discussed in this paper.  相似文献   

7.
During the late Cretaceous to early Paleogene, the present-day area of Britain and Ireland emerged from nearly total submergence by the chalk sea. What mechanism was responsible for this major marine regression? Combined studies of Paleogene depositional sequences offshore and coeval igneous rocks onshore, show that significant episodic uplift of northern Britain was at that time largely controlled by the early development of the Iceland mantle plume. How far south did this influence of the Iceland plume extend across England, and even beyond? We present new maps of the structure and denudation of the chalk surface in southern England. Some 500 m thickness of chalk was removed from the crest of a Chilterns–East Anglia dome before deposition of the earliest Paleogene sediments. Allowing for isostatic amplification by erosion, minimum uplift of the chalk surface above sea level was c.125 m. Early Paleogene crustal shortening of that chalk surface was by a factor of at most 1.01, contributing a maximum uplift of 25 m of the floor of the chalk sea. Compressional forces were not the main cause of the Cretaceous–Paleogene unconformity in southern England, as in the interpretation of this event as a distant reflection of the development of the Alps to the south. Postulated contemporary changes in global sea-level are also inadequate to account for the development of the unconformity in southern England. Here we suggest with some confidence that the main vertical surface movements involved in creating the unconformity were controlled by the Iceland mantle plume, as in northern Britain. We speculate that another hotspot, in Central France, may have influenced Paleogene sedimentation in the Paris Basin in a comparable fashion. We consider how to distinguish between our proposed mantle control of regional relative sea-level and global controls of Paleogene sea level.  相似文献   

8.
9.
Although it represents but one geographic data point, the uppermost Maastrichtian Hell Creek Formation (HCF), exposed in the upper Great Plains of the North American craton, remains the most studied source for understanding the final ∼1.5 Myr of the Mesozoic Era in the terrestrial realm. Because it lies conformably below the earliest Paleocene Fort Union Formation, and together these two units preserve a rich fauna and flora, much of what is understood about the terrestrial Cretaceous–Paleogene (K–Pg) boundary comes from this sequence.The HCF has been reconstructed as an expansive, fluvially drained, low coastal plain, built out, to the west, against the Laramide Orogen, and to the east, against the ultimate transgression (Cannonball) of the Western Interior Sea. Its meandering rivers and moist soils supported a multi-tiered angiosperm-dominated flora and rich insect and vertebrate faunas, including dinosaurs, crocodilians, squamates, turtles, and mammals. A dramatic facies change representing the initiation of catastrophic flooding is preserved, within available levels precision, at the K–Pg boundary.High-precision stratigraphy has proven difficult in this lenticular fluvial system. Where present, the boundary can be recognized by the bipartite boundary claystone; otherwise, palynostratigraphy has proven a powerful tool. Numerical dates have been successfully obtained from in tonsteins at the boundary and above, in the Fort Union; however, these have proven elusive below the boundary within the HCF. The K–Pg boundary in this region is dated at 66.043 Ma (Renne et al., 2013). Magnetostratigraphic studies have been carried out in the HCF; although all but one have lacked numerical dates, these have been used for correlations of widespread, disjunct exposures and for the estimation of sedimentation rates.The palynoflora is largely homogenous through the HCF; at the K–Pg boundary, it shows an abrupt ∼30% extinction. This makes it a powerful tool for identification of the K–Pg boundary, although because the boundary is identified on absence of Cretaceous taxa rather than presence of earliest Paleocene taxa, several competing methods have been applied to identifying the K–Pg boundary using pollen.The macroflora, consisting largely of leaves, consists of three successive floras, showing increasing diversity through the HCF. The ultimate of these three floras undergoes an abrupt 57% extinction; taken as a whole, however, the macroflora undergoes a 78% extinction at the K–Pg boundary.The best data available for dinosaurs – including archaic Aves – show an abrupt extinction. By contrast, salamanders and other lissamphibians, as well as chelonians, cross the boundary virtually without perturbation. Squamates appear to have suffered significant extinctions at the K–Pg boundary, as did euselachians (elasmobranchs) and insects. Mammals suffered a 75% extinction; however, some of this figure cannot be shown to have occurred in less than the last 500 kyr of the Cretaceous, and thus has been potentially attributable to causes other than a bolide impact. Taken together, the survivorship patterns are concordant with the catastrophic inception of ubiquitous flooding characterizing the K–Pg boundary.While the key K–Pg boundary question in the HCF was once the rate of the biotic extinction, it has moved to the distinction between single-cause scenarios, with the Chicxulub bolide as agent of extinction, and multi-cause scenarios, uniting habitat partitioning, Deccan flood-basalt volcanism, climate change, competition, and bolide impact. Not every potential environmental perturbation need be a mechanism for the extinction: parsimony and the data continue to be concordant with a bolide impact as the single agent of the terrestrial K–Pg mass extinction.  相似文献   

10.
《Cretaceous Research》2008,29(1):168-173
Matsukawa et al. present a new interpretation of the age and geological correlation within the Tetori Group. Comparison of their data with our own studies and literatures, we comment on some problems remain unsolved in their paper, such as (1) stratigraphy of the Takinamigawa area, where various fossils including dinosaurs were recovered; (2) recognition of the Akaiwa and Tamodani floras, constituents of the Tetori-type flora; (3) geological correlation of the Tetori Group between the Mt. Hakusan and Kuzuryugawa regions. Further combination of lithostratigraphy and other correlation methods is required to improve the understanding of the stratigraphy of the Tetori Group.  相似文献   

11.
12.
A well-preserved forewing of the damsel–dragonfly Stenophlebia liaoningensis sp. nov. is described from the Lower Cretaceous Yixian Formation in the Huangbanjigou Village, western Liaoning, China. This is the first discovery of the genus Stenophlebia in China, although it was widely distributed in Europe during the Late Jurassic. The discovery adds to the biodiversity of Stenophlebiidae in the Chinese Cretaceous, and provides insight on the evolution of this extinct family.  相似文献   

13.
For a long time the Moslavačka Gora Massif in Croatia has been regarded as a major outcrop of Variscan crystalline basement of the South Tisia block. However, new geochronological data indicate that this massif consists of a Cretaceous S-type granite pluton intruding a Cretaceous low-pressure/high-temperature (LP/HT) metamorphic envelope. The age of the LP/HT metamorphism is estimated at ~90–100 Ma using the method of electron microprobe based monazite dating. The Central Granite was dated at 82 ± 1 Ma (LA-SF-ICP-MS zircon age). The metamorphic complex comprises mainly felsic anatexites and orthogneisses of granitic composition, some metapelites (paragneisses and mica schists) and amphibolites. Zircons from three different samples of metagranite were dated at 486 ± 6, 483 ± 6, and 491 ± 1 Ma, suggesting that most of the metamorphic complex represents an Early Ordovician granitic series. The Cretaceous regional metamorphism culminated in granulite facies conditions of ~750°C and 3–4 kbar. A retrograde metamorphic event at lower amphibolite facies conditions overprinted the metamorphic complex. This event is probably related to the intrusion of the Central Granite. The southeastern sector of the massif was additionally affected by post-granitic, predominantly NE oriented shearing at greenschist facies conditions. As yet there is no clear evidence for Variscan events in the Moslavačka Gora Massif. Mineral relics of a medium-pressure amphibolite facies metamorphism are preserved in amphibolites. They are older than the Cretaceous LP/HT regional metamorphism, but their age is presently unknown. Some indications for a Permian regional metamorphic event are provided by inherited zircons in the Central Granite that have been dated with a Permian age, and by Permian monazite relics in metapelites. The Cretaceous high heat flow regime recorded in the Moslavačka Gora Massif is unique in the subcrop of the Pannonian Basin and may be a local feature triggered by a mafic intrusion in the lower crust.  相似文献   

14.
U–Pb geochronological studies of igneous rocks of the Crimean Mountains were carried out for the first time. The ages of magma crystallization determined for gabbro–dolerites of the Dzhidair and Pervomaiskii intrusions point to the injection of these rocks during the Middle Jurassic Aalenian–Bajocian stage of magmatism. The Berriasian–Valanginian and Aptian age of sill-like bodies within the mass of volcanogenic–sedimentary rocks presumes the necessity to reconsider the common notion of an exclusively Albian magmatic event during the Cretaceous. High-precision U–Pb dating of magma intrusions allowed us to verify the age of Middle Jurassic magmatism and to distinguish the new Early Cretaceous Berriasian–Valanginian magmatism stage of basic composition.  相似文献   

15.
16.
Basal iguanodontians (“iguanodontids”) were a successful group of ornithopod dinosaurs that attained a near global distribution by the late Early Cretaceous. Despite their body fossils being known in abundance from the uppermost Jurassic and Lower Cretaceous of the western United States, their remains have never been found in western Canada. With its extensive, terrestrial sedimentary record for the whole of the Early Cretaceous, the expectation is that these dinosaurs would have been present in western Canada. This paper reports the finding of a fossil footprint from the Gladstone Formation in southwestern Alberta that is interpreted to have been made by an iguanodontid. This identification is based on the late Barremian age of the hosting rock, gross footprint details that match the skeletal foot structure of Iguanodon bernissartensis, and similarities to Early Cretaceous dinosaur footprints found elsewhere in the world that are attributed to iguanodontids. This finding fills a noticeable gap in the iguanodontian fossil record, and is consistent with the clade's attainment of global distribution during the Early Cretaceous.  相似文献   

17.
《Comptes Rendus Geoscience》2019,351(7):498-507
The Cretaceous marine transgression proceeded through successive steps from the Albian to the Turonian (dated with ammonites). The onlapping wedge begins with coastal transgressive–regressive short-term sequences on massive, probably fluvial sandstones to be correlated with the very thick continental Lower Cretaceous succession found in the Puerto Cansado well in the Tarfaya sub-basin to the north. A second step, of probable Cenomanian age, reached the Palaeozoic basement. A third, more pronounced step occurred during the earliest Turonian with platy laminated limestone overlain by marlstone bearing pyritized ammonites. At early Turonian peak transgression, a marine connection was possibly established between the Atlantic and the Tethyan margins, between the Anti-Atlas and the Reguibat Shield. From large-scale correlation integrating what occurred along the southwestern shoulder of the Atlas rift, the South Moroccan Atlantic margin may have undergone a short-lived tectonic uplift around the Cenomanian–Turonian boundary.  相似文献   

18.
Sedimentary Characteristics of the Cretaceous in the Songliao Basin   总被引:2,自引:0,他引:2  
The rupture of the lithosphere in Late Jurassic brought about the eruption of basaltic magma in the Songliao Basin. The evolution of the basin in Cretaceous progressed through six stages: pre-rift doming, extensional fracturing, fault subsidence, fault downwarping, downwarping and shringkage, resulting in the deposition of terrstrial facies nearly 10,000 m thick. There are different depositional sequences in these stages: the depositional period of the Early Cretaceous Shahezi and Yincheng Formations is the development stage of the down-faulted basin, forming a volcanic rock-alluvial fan-fan delta-lacustrine (intercalated with episodic turbidites)-swamp facies sequences; the period of the Early Cretaceous Dengluku Formation is the transformation stage of fault subsidence into fault downwarping of the basin, forming a sequence mainly of alluvial plain-lacustrine facies; the depositional period of the Early Cretaceous Quantou Formation-Late Cretaceous Nenjiang Formation is the downwarping stage of the basin, forming an alluvial plain-delta-lacustrine facies sequence; the period of the Late Cretaceous Sifangtai Formation-Mingshui Formation is the shringkage stage of the basin, forming again a sequence mainly of alluvial plain-alluvial fan and small relict lacustrine facies. These vertical depositional sequences fully display the sedimentary characteristics of a failed continental rift basin. Many facts indicate that the two large-scale lake invasions, synchronous with the global rise of sea level, which took place in the downwarping stage of the basin development, led to the connection between the lake and sea.  相似文献   

19.
The fossil taxa of the Cenomanian continental flora and fauna of São Luís Basin are observed primarily in the bone bed of the Laje do Coringa, Alcântara Formation. Many of the disarticulated fish and tetrapod skeletal and dental elements are remarkably similar to the chronocorrelate fauna of Northern Africa. In this study, we present a summary of the continental flora and fauna of the Laje do Coringa bone-bed. The record emphasizes the existence of a trans-oceanic typical fauna, at least until the early Cenomanian, which may be interpreted as minor evolutionary changes after a major vicariant event or as a result of a land bridge across the equatorial Atlantic Ocean, thereby allowing interchanges between South America and Africa. The paleoenvironmental conditions in the northern Maranhão State coast during that time were inferred as forested humid areas surrounded by an arid to semi-arid landscape.  相似文献   

20.
Early Cretaceous sediments of Aptian–Albian age outcrop at Munday’s Hill Quarry, Bedfordshire, England. Previous papers describing the section have resulted in different terminologies being applied. The Lower Cretaceous in Bedfordshire is represented by sediments belonging to the Lower Greensand Group and the Gault Clay Formation. Within the Lower Greensand Group in the study area the Woburn Sands Formation, are of Aptian–Albian age. Selected samples have been analysed for palynology. The analysis reveals diverse palynomorph assemblages, including well-preserved dinoflagellate cysts and sporomorphs. Comparison of the assemblages with published records indicates that the lower samples are of Late Aptian age. Forms recorded include common Kiokansium unituberculatum, Cerbia tabulata, Aptea polymorpha and Cyclonephelium inconspicuum. An Early Albian age is indicated for the uppermost sample.  相似文献   

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