A new structurally preserved fern rhizome of Osmundaceae (Filicales) Ashicaulis wangii sp. nov. from the Jurassic of western Liaoning and its significances for palaeobiogeography and evolution

Permineralized osmundaceous rhizome with anatomical and phylogenetic information plays a significant role in understanding the origin,evolution,and diversity variation of the fern family Osmundaceae in geological history.The northern Hebei and western Liaoning region is one of the most important fossil localities for the Jurassic osmundaceous rhizome fossils in the Northern Hemisphere;however,the diversity character of osmundaceous rhizome fossil remains poorly known.A new structurally preserved fern rhizome species,Ashicaulis wangii sp.nov.,is described from the Middle Jurassic Tiaojishan Formation in Beipiao City,Liaoning Province,northeastern China.The rhizome is composed of heterogeneous pith,an ectophloic–dictyoxylic siphonostele,a two–layered cortex,and a mantle of adventitious roots and petiole bases.The xylem cylinder,with complete leaf gaps,consists of 15–17 xylem strands.The petiole base is characterized by a heterogeneous sclerotic ring and numerous sclerenchyma masses in the petiolar cortex.Among five known Ashicaulis species with heterogeneous sclerotic ring,four of them are documented from China.Therefore,osmundaceous rhizome fossils from China show endemic anatomical characteristics and significances for palaeobiogeography.Comparisons of anatomical features suggest that A.wangii sp.nov.bears close similarities to Osmunda pluma Miller from the Paleocene of Dakota,USA.Fossil species of A.wangii provides new evidence for further understanding the species diversity of osmundaceous rhizome fossil in China and in the Northern Hemisphere,and contributes to exploring the macroevolution process of the Mesozoic osmundaceous plants.     

The oldest angiosperm—a tricarpous female reproductive fossil from western Liaoning Province, NE China

The fossil plant female reproductive organs each with a tricarpous were collected from the Yixian Formation, Chaoyang district, western Liaoning Province. The geological age of the Yixian Formation here is believed to be Late Jurassic, which places this fossil as the oldest angiosperm currently known. Its morphological characters are distinct from other known angiosperm reproductive organs as it has 3 ovaries, each with a terminal style and an apical stigma. 9 such organs compose a cyme. As this morphological arrangement is unique to this plant, a new genus and species has been established, namedChaoyangia liangii gen. et sp. nov. Project supported by the Special Finances of Biological Sciences and Technology, Chinese Academy of Sciences (the special item of the Ministry of Finance of the People’s Republic of China).     

New fossil eccoptarthrids (Coleoptera: Curculionoidea) from the Yixian Formation of western Liaoning, China

One new genus and three new species of the weevil family Eccoptarthridae (Curculionoidea), Leptocar polychaetus gen. et sp. nov., Abrocar macilentus sp. nov., Cretonanophyes punctatus sp. nov., are described and illustrated. They pertain to the Upper Jurassic or Lower Cretaceous Yixian Formation of western Liaoning Province, China. The host plants to the living eccoptarthrids and the floras in Yixian Formation indicate that those archaic eccoptarthrids possibly lived on conifers with a phylogenetic closeness to Cupressaceae. Besides, the early diversification of eccoptarthrids is discussed: origi- nated in Central or East Asia in the Late Jurassic, spread into Western Europe and South America during the Early Cretaceous, underwent a dramatic decline after the Early Cretaceous which likely was caused by competitive pressure and the displacement of their host plants.     

Constraints on the age of the Tuchengzi Formation by LA-ICP-MS dating in northern Hebei-western Liaoning,China

Accurately determining the age of the Tuchengzi Formation has direct influence on confirming the boundary between the Jurassic and the Cretaceous systems in northern Hebei-western Liaoning, and on related geological problems in China. However, the Tuchengzi Formation mainly consists of sedimentary rocks, with a poor fossil record and especially lack of index fossils. The Tuchengzi Formation is also lack of the type of volcanic rocks that can provide an isotopic age. Therefore, the age of the Tuchengzi Formation has been uncertain. Based on our systematic dating of the tuff interbedded in the Tuchengzi Formation of Chengde and Jinlingsi-Yangshan basins in northern Hebei-western Liaoning, combined with the dating results of previous researchers, here we suggest that the age range of the Tuchengzi Formation in northern Hebei-western Liaoning is from 147 Ma to 136 Ma. It implied that the Tuchengzi Formation was mainly formed in the Early Cretaceous. Supported by National Natural Science Foundation of China (Grant No. 90714010)     

Geochemistry and U-Pb zircon geochronology of Late-Mesozoic lavas from Xishan, Beijing

The North China craton (NCC) is distinctively dif-ferent from other Archean craton around the world due to violent construction-magmatic activity, ore deposi-tion and basin formation process and the deep dynam-ics could be probably related with lithospher…     

Jurassic integrative stratigraphy and timescale of China

The Jurassic stratigraphy in China is dominated by continental sediments. Marine facies and marine-terrigenous facies sediment have developed locally in the Qinghai-Tibet area, southern South China, and northeast China. The division of terrestrial Jurassic strata has been argued, and the conclusions of biostratigraphy and isotope chronology have been inconsistent.During the Jurassic period, the North China Plate, South China Plate, and Tarim Plate were spliced and formed the prototype of ancient China. The Yanshan Movement has had a profound influence on the eastern and northern regions of China and has formed an important regional unconformity. The Triassic-Jurassic boundary(201.3 Ma) is located roughly between the Haojiagou Formation and the Badaowan Formation in the Junggar Basin, and between the Xujiahe Formation and the Ziliujing Formation in the Sichuan Basin. The early Early Jurassic sediments generally were lacking in the eastern and central regions north of the ancient Dabie Mountains, suggesting that a clear uplift occurred in the eastern part of China during the Late Triassic period when it formed vast mountains and plateaus. A series of molasse-volcanic rock-coal strata developed in the northern margin of North China Craton in the Early Jurassic and are found in the Xingshikou Formation, Nandailing Formation, and Yaopo Formation in the West Beijing Basin. The geological age and markers of the boundary between the Yongfeng Stage and Liuhuanggou Stage are unclear. About 170 Ma ago, the Yanshan Movement began to affect China. The structural system of China changed from the near east-west Tethys or the Ancient Asia Ocean tectonic domain to the north-north-east Pacific tectonic domain since 170–135 Ma. A set of syngenetic conglomerate at the bottom of the Haifanggou or Longmen Fms. represented another set of molasse-volcanic rock-coal strata formed in the Yanliao region during the Middle Jurassic Yanshan Movement(Curtain A1). The bottom of the conglomerate is approximately equivalent to the boundary of the Shihezi Stage and Liuhuanggou Stage. The bottom of the Manas Stage creates a regional unconformity in northern China(about 161 Ma, Volcanic Curtain of the Yanshan Movement, Curtain A2). The Jurassic Yanshan Movement is likely related to the southward subduction of the Siberian Plate to the closure of the Mongolia-Okhotsk Ocean. A large-scale volcanic activity occurred in the Tiaojishan period around 161–153 Ma. Note that 153 Ma is the age of the bottom Tuchengzi Formation, and the bottom boundary of the Fifth Stage of the Jurassic terrestrial stage in China should have occurred earlier than this. This activity was marked by a warming event at the top of the Toutunhe Formation, and the change in the biological assembly is estimated to be 155 Ma. The terrestrial Jurassic-Cretaceous boundary(ca. 145.0 Ma) in the Yanliao region should be located in the upper part of Member 1 of the Tuchengzi Formation, the Ordos Basin in the upper part of the Anding Formation, the Junggar Basin in the upper part of the Qigu Formation, and the Sichuan Basin in the upper part of the Suining Formation The general characteristics of terrestrial Jurassic of China changed from the warm and humid coal-forming environment of the Early-Middle Jurassic to the hot, dry, red layers in the Late Jurassic. With the origin and development of the Coniopteris-Phoenicopsis flora, the Yanliao biota was developed and spread widely in the area north of the ancient Kunlun Mountains, ancient Qinling Mountains, and ancient Dabie Mountain ranges in the Middle Jurassic, and reached its great prosperity in the Early Late Jurassic and gradually declined and disappeared and moved southward with the arrival of a dry and hot climate.     

Paleomagnetic evidence for Jurassic deformation of the McCoy Mountains Formation,southeastern California and southwestern Arizona

The Mesozoic McCoy Mountains Formation is a 7.3-km-thick deformed clastic sequence exposed in six mountain ranges in southeastern California and southwestern Arizona. Interbedded with Jurassic volcanic rocks at its base, the McCoy Mountains Formation had been assigned a Cretaceous age based upon fossil angiosperm wood found in the upper third of the section. Characteristic natural remanent magnetism (NRM) from 145 oriented samples from 18 sites within the sedimentary terrane yield an in situ mean direction:I = 20.6°, D = 335.1°, α₉₅ = 7.7° (uncorrected for structural tilting). Opaque mineralogy and a failed fold test indicate that the NRM is a chemical remanence acquired post-folding. The paleomagnetic pole position calculated from the in situ mean direction falls adjacent to poles from the Summerville Formation and Canelo Hills Volcanics. We interpret these data to indicate that deformation, mild metamorphism, and resultant magnetization of the McCoy Mountains Formation occurred during Jurassic time. It is suggested that the McCoy Mountains Formation and underlying Jurassic volcanics were deposited adjacent to, and then deformed between, the North American craton and an outlying allochthonous terrane during Jurassic time.     

Response to paleoatmospheric CO<Subscript>2</Subscript> concentration of <Emphasis Type="Italic">Solenites vimineus</Emphasis> (Phillips) Harris (Ginkgophyta) from the Middle Jurassic of the Yaojie Basin,Gansu Province,China

Solenites vimineus (Phillips) Harris (Ginkgophyta) specimens with well-preserved cuticles were collected from five different beds in the oil shale member of the Middle Jurassic Yaojie Formation in the Yaojie Basin, Gansu Province, northwestern China. Gross morphology and fine structures of the fossil leaves were studied, and stomatal parameters were analyzed, according to which, the paleoatmospheric CO₂ concentration can be deduced as 1512–1896 ppm that would have caused an increase in mean temperature of about 6.5–7.4°C. Carbon isotopes from the fossils indicate that the carbon isotopic discrimination and water use efficiency (WUE) of S. vimineus were raised nearly obtaining the ideal physiologic state in increased CO₂ concentrations and temperature conditions, suggesting that S. vimineus records the paleoenvironmental information of the Middle Jurassic Yaojie Basin and can be used for environmental reconstruction.     

Seismic event, sequence and tectonic significance in Canglangpu Stage in Paleo-Tanlu Fault Zone

The Canglangpu Stage of Lower Cambrian Series is widely distributed along both sides of the Tanlu (Tancheng-Lujiang) Fault Zone in the Jiao-Liao-Xu-Huai regions. In the Liaodong Peninsula, the Canglangpu Stage consists of three formations, i.e. Gejiatun, Dalinzi and Jianchang formations in ascending order (lying on the eastern side of the Tanlu Fault Zone). The Dalinzi Formation, developing in a littoral Sabkha environment, is full of catastrophic event records of violent seism, such as liquefied muddy-sandy veins, hydroplastic folds, hydroplastic micro-faults (three forming an organic whole), liquefied crinkled deformations, liquefied breccia and sandy dikes. Based on such records, the seismic liquified sequence of argillaceous rocks in Sabkha is built up. In northern Jiangsu and Anhui provinces, however, there hardly observe seismic records in the Canglangpu Stage, which consists of Jinshanzhai and lower Gouhou and upper Gouhou formations (lying on the western side of the Tanlu Fault Zone). Even if the Gouhou Formation, developing in a lagoon-dry environment, is in the same climate zone as the Dalinzi Formation, and 4 depositional sequences have been identified in the Canglangpu Stage in Northern Jiangsu and Anhui provinces, however, in the same stage in the Liaodong Peninsula, there exist only 3 ones. Therefore, it is not supported by the above mentioned evidence (such as catastrophic events, sequences stratigraphy and lithologic correlation of formations) that the Canglangpu Stage in the Liaodong Peninsula came from northern Jiangsu and Anhui provinces through a long-distance, about hundreds kilometers, left-hand displacement of the Tanlu Fault in the Mesozoic era.     

跨断层水准测量与朝阳—北票断裂现今活动性

本文利用桃花吐及北票场地１９９０年－１９９６年跨断层短水准测量资料，并结合同期的重力测量资料，研讨了朝阳－北票断现今活动性，得出了几条有益的结论。     

Seismic stratigraphy and sedimentation history of the East Mariana Basin,western Pacific

An interpretation of the seismic stratigraphy and sedimentation history of the East Mariana Basin has been made using recently collected seismic reflection and refraction data. This Mesozoic(?) age basin, between the Marshall Islands and the Mariana Trench, is subdivided into three regions. The central region with about 1000 m of sediment probably records Jurassic to Late Cretaceous sedimentation of a pelagic biogenic and clay-rich section overlain by a thick section of mainly Cenozoic carbonates shed from nearby volcanic platforms. A western region is characterized by a thinner sediment cover and a shallower acoustic basement with a similar sedimentation history except that the upper section is thinner as a consequence of fewer nearby volcanic highs. Extensive Late Cretaceous mid-plate volcanics apparently masks the lower section and forms acoustic basement. The shallower eastern region (east of 157.5°E) contains WNW-trending ridges which may be either fracture zones or high-amplitude abyssal hills. The sedimentation appears controlled by the same factors as in the other regions but the area was bypassed by most Cenozoic basin-filling turbidites because of its elevation.The isostatistically corrected basement depths between the three regions suggest that the crust in the east may be substantially younger than in the rest of the East Mariana Basin, perhaps Cretaceous in age. This requires the existence of a tectonic boundary within the basin.     

北票台吉地震与辽西地震相关分析

辽西地区被国家地震局列为“重点监测区”,该区区域构造复杂,近年来小震活动频繁,北票台吉地区处在辽西的中心部位,通过几年的观测研究,该区的小震活动与辽西地震活动有着很好的相关性。本文对北票台吉地震进行了各种分析研究,认为北票台吉地震与辽西地震有着很好的相关性,存在“窗口效应     

Effect of Mesozoic volcanic eruptions in the western Liaoning Province,China on paleoclimate and paleoenvironment

Volatiles emitted during volcanic eruptions have an significant effect on the climate and environmental changes[1]. Different compositions of volatiles released may result in different trends of climate and environmental changes. Amounts of the erupted …     

Geostatistical Interplay Between Geophysical and Geochemical Data: Mapping Litho-Structural Assemblages of Mesozoic Igneous Activities in the Parnaíba Basin (NE Brazil)

Two widespread magmatic events are recorded in the Parnaíba basin (NE Brazil) during the Jurassic/Cretaceous opening of the Central and South Atlantic Oceans. The Early Jurassic (~ 200 Ma) lava flows of the Mosquito Formation occur essentially in the western and southern basin segments, representing one of the largest expressions of the Central Atlantic Magmatic Province in the South American Plate. In contrast, sill complexes and dike swarms of the Early Cretaceous (129–124 Ma) Sardinha Formation occur in the eastern part of the basin and are chrono-correlated to the large Paraná–Etendeka igneous province and to the Rio Ceará–Mirim Dike Swarm. We gathered geophysical, well logging, outcrop analogs and geochemical data to recognize geometrical shapes and areal distribution patterns of igneous-related constructions. Seismic and well data reveal hundreds of km wide multilayered sill complexes and dikes, which are widespread across vast regions of the basin without evident structural control from either the Precambrian basement grain or the basin internal architecture. Anomaly enhancement techniques and self-organizing maps (SOM) procedure were applied on airborne magnetic data, unraveling near-surface magmatic features in four distinct magnetic domains. Using SOM analysis, the basaltic rocks were divided into six groups based on magnetic susceptibility and major elements composition. These results suggest common origin for both magmatic episodes, probably a combination of effects of edge-driven convection and large-scale mantle warming under the westward moving West Gondwana during the Central and South Atlantic opening, which caused a shifted emplacement to the east of the igneous rocks in the Parnaíba basin.     

Revision of Cyprinus maomingensis Liu 1957 and the first discovery of Procypris-hke cyprinid(Teleostei,Pisces) from the late Eocene of South China

Fossil cyprinids from the upper part of the upper Eocene Youganwo Formation of Maoming, Guangdong, China were first studied in 1957 by Liu, who referred the only specimen to the genus Cyprinus as a new species, C. maomingensis. And this was suggested as one of the earliest records for fossil cyprinids. Unfortunately, this specimen is poorly preserved and reveals no more morphological information than its serrated last unbranched dorsal and anal fin rays. Recently, some new specimens were unearthed from the same locality, where C. maomingensis was discovered. In addition to the serrated dorsal and anal fin rays, these new materials also show that the pattern and shape of their pharyngeal teeth obviously differ from that of Cyprinus but resemble that of Procypris. However, its number of the branched dorsal fin rays and number of vertebrae are much less than that in Procypris. Morphologically, these specimens are closer to Procypris than to Cyprinus. This is the first report of fossil Procypris-like fish, and it implies that Procypris-like fish is an early member of the Tribe Cyprinini sensu stricto(sensu Yang et al., 2010) and the origin of this group can be traced back at least to the late Eocene.     

Klukiopsis jurassica--A new Jurassic schizaeaceous fern from China

A new Jurassic schizaeaceous fern Klukiopsis jurassica gen. et sp. nov. from Yima, Henan Province, China is described. The new fern is characterized by the abaxial sori arranged in two rows, apical and complete annulus and more than 800 smooth trilete spores in each sorus.     

Palynomorph assemblages and paleoclimate records from the Zhuanchengzi Bed of the Yixian Formation,western Liaoning Province,China

We collected, processed, identified, and analyzed the spores and pollen samples from the Zhuanchengzi Bed of the Yixian Formation in the Yingwoshan area of western Liaoning. As a result, we confirm a palynomorph assemblage of Cicatricosisporites-Protoconiferus. The pollen was primarily from gymnosperms, dominated especially by conifer pollen. Pteridophyte spores were less common and some questionable angiosperm pollen occurred occasionally. The age of the palynomorph assemblage is dated as the late Valanginian or Hauterivian-Barremian stage, the Early Cretaceous. The study applies the concept of Palynological Vegetation based on palynological spectra and the paleoecological characteristics of palynological taxa for the first time. Palynological vegetation type, climatic zone type, and humidity type are divided quantitatively for the Zhuanchengzi Bed in the Yixian Formation of western Liaoning. We then obtained the evolutionary trends. The results showed that the overall climate was warm and humid during the deposition period of the Zhuanchengzi Bed in the Yixian Formation. Palynological vegetation types are various and include coniferous forest, deciduous broadleaf forest, evergreen broad-leaved forest, grass, and shrubs. The local temperature changed from warm to much warmer and from a semi-humid to humid climate. Palynological vegetation types are always dominated by coniferous forest. The coexistence of deciduous broad-leaved forest, evergreen broad-leaved forest, shrubs, grass, and some xerophytic plants indicates vertical zonation and seasonal climate change The vertical vegetation types and the warm humid climate may imply a large geomorphological contrast in the Yixian Formation of western Liaoning.     

Klukiopsis jurassica—A new Jurassic schizaeaceous fern from China

A new Jurassic schizaeaceous fernKlukiopsis jurassica gen. et sp. nov. from Yima, Henan Province, China is described. The new fern is characterized by the abaxial sori arranged in two rows, apical and complete annulus and more than 800 smooth trilete spores in each sorus.     

辽宁海城M4.3地震强震记录分析

2008年辽宁海城M 4.3地震,辽宁省强震动台网12个强震台站记录到地面运动,是辽宁省自开展强震动观测以来同时获取强震记录最多的一次,记录的最大加速度为167.5 cm·s-2,初步展现了辽宁省强震动台网建设的成效.     

Clustering Analysis of Spatial Distribution of Seismicity in the Yellow Sea and Bohai Sea

According to tie records of seismic station networks of China's continent and Korea Peninsula and the historical data,the complete seismicity pattern was obtained for the first time.The seismic zoning was conducted by means of the cluster analysis method.The map's spatial distribution of seismicity from 1960 to 1994 shows that there are three strong seismic zones:the first one strikes in the NE direction,from the Jiangsu plain in China to the central Korean Peninsula; the second strikes in the NW direction,from the Bohai Sea,China to the southern Korean Peninsula; the third strikes in the NW direction,from the western Liaoning Province to Pyongyang.Most of earthquakes are located along these three zones,the seismic intensity is lower than that in the mainland,and exhibited the feature of fractured crust of a marginal sea basin.