Twenty-three ichnotaxa have been found in the Silurian and Carboniferous turbidites of the Tianshan orogenic belt and the Triassic turbidites of the East Kunlun-West Qinling orogenic belt of northwestern China. They a...Twenty-three ichnotaxa have been found in the Silurian and Carboniferous turbidites of the Tianshan orogenic belt and the Triassic turbidites of the East Kunlun-West Qinling orogenic belt of northwestern China. They are Acanthorhaphe isp., ?Arthrophycus isp., Aulichnites parkerensis, Chondrites isp., C. intricatus, C. targionii, Cochlichnus anguineus, coprolite, Dendrotichnium haentzscheli, Helminthopsis isp., Helminthopsis abeli, H. hieroglyphica, H. cf. irregularis, Imbrichnus isp., Kunlunichnus qinghaiensis, Laevicyclus rotaeformis, Lophoctenium tianshanensis, Megagrapton isp., Micatuba verso?, Muensteria isp., Neonereites, Palaeophycus, and Zoophycos caudagalli, two of which, namely, Kunlunichnus qinghaiensis and Lophoctenium tianshanensis, are new ichnospecies. The described trace fossils can be grouped into five ichno-assemblages: the Aulichnites-Imbrichnus ichno-assemblage representing turbidity current deposits of a restricted anoxic deep-sea basin, the Lophoctenium ichno-assemblage showing the deep-sea or ocean environments relevant to a plate subduction, the Zoophycos-Helminthopsis ichnoassemblage representing the upper-middle turbidity fan deposits of a pelagic and hemipelagic environment, the Megagrapton-Chondrites ichno-assemblage representing the middle-lower turbidity fan deposits of an oceanic archipelago and the Kunlunichnus ichno-assemblage indicating bathyal turbidity current deposits.展开更多
Based on the analysis of trace fossils collected from the typical outcrop of the Lower Cambrian Wusongger Formation in the Kalpin area, ten ichnospecies of six ichnogenus were identified in the upper member of the Wus...Based on the analysis of trace fossils collected from the typical outcrop of the Lower Cambrian Wusongger Formation in the Kalpin area, ten ichnospecies of six ichnogenus were identified in the upper member of the Wusongger Formation, with most of them being found for the first time. The trace fossils are described seriatim. The ichnospecies are mainly represented by such common trace fossils as Ophiomorpha nodosa, Helminthopsis hieroglyphica, Helminthopsis ichnosp., Planolites beverleyensis, Planolites vulgaris, Planolites montanus, Palaeophycus striatus, Palaeophycus curvatus, Cochlichnus anguineus and Rituichnus elongatum. The trace fossils are of high diversity and low abundance, and can be diagnosed as the Cruziana ichnofacies. They can be interpreted as having formed in a shallow water environment.展开更多
There are abundant and highly varied trace fossils in the Sinian-Cambrian boundary beds in eastern Yunnan. Collections from 27 sections and their study give altogether 45 ichnogenera and 87 ichnospecies. Among them, 2...There are abundant and highly varied trace fossils in the Sinian-Cambrian boundary beds in eastern Yunnan. Collections from 27 sections and their study give altogether 45 ichnogenera and 87 ichnospecies. Among them, 2 ichnogenera and 7 ichnospecies are new, and 31 known ichnogenera and 38 known ichnospecies first found in the region. According to their order of appearance in the boundary beds and their assemblage features, the trace fossils in the Sinian-Cambrian boundary beds in the region may fall into 4 trace fossil assemblage zones in ascending order. In the paper they are correlated with those in the equivalent horizons abroad and their geological significance is discussed preliminarily.展开更多
Six ichnogenera,Chondrites,Palaeophycus,Planolites,Rhizocorallium,Skolithos,and Thalassinoides,were identified from the drilling cores near the Global Stratotype Section and Point(GSSP) of Permian-Triassic boundary at...Six ichnogenera,Chondrites,Palaeophycus,Planolites,Rhizocorallium,Skolithos,and Thalassinoides,were identified from the drilling cores near the Global Stratotype Section and Point(GSSP) of Permian-Triassic boundary at Meishan,Zhejiang Province.The ichnological indices,including abundance,bioturbation index,and disturbed depth of trace fossils,show two episodes of intense changes near the Permian-Triassic Boundary(PTB).Episode I occurred in Beds 25-27b when the ecologically complicate forms such as Chondrites,Skolithos,Rhizocorallium,and Thalassinoides disappeared hereafter,the bioturbation index reduced from 1-5 to 1-3,and the disturbed depth declined from 5-66 to 2-5 cm.Episode II took place at the base of Bed 33 with the disappearance of Palaeophycus and Planolites,and subsequent absence of trace fossils and bioturbation till the middle-upper part of Bed 41 when the disturbed structures reoccurred,but they are only tiny Planolites and the bioturbation index was never higher than 3 and the disturbed depth less than 4 mm.Episode I shows an intense change,corresponding to the main stage of the end-Permian mass extinction,whereas Episode II is relatively weak,corresponding to the epilogue of the mass extinction of trace makers in the Early Triassic.Subsequently,ichnofossils were dominated by surface tracks in simple ecological habit and structures.This phenomenon indicates that the Early Triassic benthonic fauna is changed from sessile benthic system to mobile benthic system after the end-Permian mass extinction.In other words,the evolution of the trace fossils across the Permian-Triassic transition had an episodic process similar to the body fossils.In addition,the change of ichnofabrics is well coincided with the negative excursion of carbon isotopes and the expansion of cyanobacteria.As the results of physical and biogenic processes,trace fossils provided unique materials for the study of the biotic and environmental events,as well as their coupling evolution through the great Permian-Triassic transition.展开更多
The uppermost part of the Upper Bathonian Sponge Limestone member, Patcham Formation, of the Jhura Dome of Kachchh Mainland is a thickening-and shallowing-upward succession topped by medium-to thick-bedded hummocky cr...The uppermost part of the Upper Bathonian Sponge Limestone member, Patcham Formation, of the Jhura Dome of Kachchh Mainland is a thickening-and shallowing-upward succession topped by medium-to thick-bedded hummocky cross-stratified grainstones deposited by storm waves. Occasionally, thin, commonly lenticular, intraclastic-bioclastic silty marl intercalations between the grainstones are highly bioturbated, in contrast to the grainstones, in which, for the most part, trace fossils occur scattered. Large exposures of bedding planes of the grainstones allow the detailed investigation of ichnological features, whereas the high density of traces in the soft marls precludes the identification of any ichnotaxa. Eighteen ichnotaxa have been recorded including Ophiomorpha, Thalassinoides, Taenidium, Gyrophyllites, Chondrites, Dactyloidites, Teichichnus, Bolonia, and Ancorichnus. Except for Ophiomorpha nodosa and Thalassinoides, which generally indicate moderate to high energy conditions and are the dwelling burrows of suspension-feeding to omnivorous crustaceans, the ichnotaxa represent a deposit-feeding behaviour of their producers and thus are characteristic of low-energy environments. The trace fossils form three ichnoassemblages characterized by(1) Ophiomorpha nodosa and Thalassinoides suevicus,(2)?Thalassinoides isp. A, Taenidium, and Bolonia lata,and(3) Ancorichnus. The dominance of traces of deposit-feeders in rocks indicative of high-energy events is counterintuitive and points to their non-contemporaneity. The sediments were deposited during brief highenergy events, whereas the trace fossils were produced when, after waning of storms low-energy conditions prevailed. This time-averaging is particularly pronounced in trace fossils that extend vertically downwards and may reach strata deposited under distinctly different conditions. Thus, environmental interpretations based on trace fossils should refer to colonisation surfaces rather than to the sediment surrounding the trace fossils. In the latter case, interpretations may be erroneous, especially when erosion subsequently destroyed sedimentary evidence of their original environment.展开更多
Over 190 specimens of an attachment ichnofossil Kailidiscus （n. ichnogen.） have been found in the Kaili Bitoa, a Burgess Shale-type biota, from the middle Kaili Formation （early Middle Cambrian） in Taijiang County...Over 190 specimens of an attachment ichnofossil Kailidiscus （n. ichnogen.） have been found in the Kaili Bitoa, a Burgess Shale-type biota, from the middle Kaili Formation （early Middle Cambrian） in Taijiang County, Guizhou Province, southern China. Kailidiscus is an epichnia with a circular to oval attachment platform, on which there is a carbonaceous film probably formed by the body of the living organism. Structures such as a marginal furrow, an inner and outer marginal ride, many convex fold-ridges, and a large caved peripheral furrow on the attachment platform may be the result of basal tissues of a sessile organism that wrinkled to increase the attachment＇s surface area. The Kailidiscus organism may have been a sessile cnidarian attached to the muddy seafioor. Kailidiscus organisms lived in relatively quiet water, and were buried by a sudden influx of sediment.展开更多
Two Upper Devonian to Lower Carboniferous sections,namely the Bulongguoer and Haer(Gennaren area)in the Junggar Basin,Central Asian Orogenic Belt,in northwestern China were examined with regard to ichnology and palyno...Two Upper Devonian to Lower Carboniferous sections,namely the Bulongguoer and Haer(Gennaren area)in the Junggar Basin,Central Asian Orogenic Belt,in northwestern China were examined with regard to ichnology and palynology.The deposits of the Hongguleleng Formation and Namu Member of the Heishantou Formation,respectively,are mostly unbioturbated or poorly bioturbated,with poorly diversified trace fossils,which indicate unfavourable conditions for the burrowing benthic community during the Late Devonian and Early Carboniferous.The main factor governing the growth of the bioturbating population was the rapid sedimentation of fine-grained,volcanic material documented as tempestites,which buried the benthic fauna.In the Bulongguoer section,the presence of miospores Teichertospora torquata and Grandispora gracilis enabled identification of the broad Teichertospora torquata–Grandispora gracilis Miospore Zone from the transitional Frasnian/Famennian interval.More accurate identification of palynostratigraphical levels(DE and CZ Miospore zones)is only tentative.On the basis of palynofacies analysis,samples from the lower Bulongguoer section indicate deposition in more proximal conditions,whereas samples from the top of the section indicate deposition in a more distal environment.In the Haer section,only a general biostratigraphic indication for the Tournaisian was possible,owing to poor preservation of organic matter.展开更多
The well known Cretaceous seaway in North America was recognized in the middle of the last century and the Palaeogene seaway in East China was proposed by the author recently. The two seaways located on the opposite s...The well known Cretaceous seaway in North America was recognized in the middle of the last century and the Palaeogene seaway in East China was proposed by the author recently. The two seaways located on the opposite sides of North Pacific Ocean may be not a coincidence, and a comparative study was made in this paper. The results show that the two seaways inundated basins share several similarities particularly in basin origin, filling processes and reservoir facies. It is suggested that reservoir facies of estuarine sandstone and shelf bar sandstone related to sea level fluctuation, which are well developed in the Cretaceous seaway covered basins in North America might have been also developed here in Palaeogene seaway inundated basins in East China. Therefore it is worth paying more attention to finding these new reservoir facies on this side of the Pacific ocean. Evidences of sedimentology and ichnology indicate that good prospects are likely.展开更多
The Lower Cambrian Nagaur Sandstone（Marwar Supergroup） has yielded trace fossils Treptichnus, Cruziana, serially repeated Rusophycus, Diplichnites, Monomorphichnus, Bergaueria,arthropod swimming traces and leap frog...The Lower Cambrian Nagaur Sandstone（Marwar Supergroup） has yielded trace fossils Treptichnus, Cruziana, serially repeated Rusophycus, Diplichnites, Monomorphichnus, Bergaueria,arthropod swimming traces and leap frogging marks of Cruziana ichnofacies. This ichnofossils assemblage is dominantly preserved in fine to medium grained red sandstone beds of the Mohra Member（Nagaur Sandstone）. The presence of graded rip-up clasts, current ripples, dune crossstratification with mud drapes and tidal bundles indicates a subtidal paleoenvironment for the deposition of Nagaur Sandstone Formation, which is corroborated by the Cruziana ichnofacies trace fossil assemblage.展开更多
Thin-bedded turbidites are important hydrocarbon-bearing reservoirs in many mature fields throughout the world.The type of turbidite depositional setting strongly influences vertical and horizontal continuity of the r...Thin-bedded turbidites are important hydrocarbon-bearing reservoirs in many mature fields throughout the world.The type of turbidite depositional setting strongly influences vertical and horizontal continuity of the reservoir.However,distinguishing between lobe and levee associated thin-bedded turbidites remains challenging due to their generally similar facies characteristics.This study aims to contribute some insights to this problem by conducting a detailed bed-scale facies analysis on the Early Miocene Temburong Formation exposed at Kampung Bebuloh,Labuan Island,Malaysia,which may uncover features that can help in differentiating between both depositional types.Six facies are recognized in the Temburong Formation,which are interpreted as low density turbidites(F1-F4),hybrid event beds(F5),and sustained turbidites(F6).Detailed facies and ichnology analysis reveal features which are consistent with a lobe fringe deposit rather than leveeassociated environment interpretation,including tabular bed geometries,presence of hybrid event beds,and the absence of thick-bedded channel-fill sandstones.Five facies associations are identified and interpreted as representing sub-environments within an overall lobe depositional setting.A diverse trace fossil assemblage,comprising the Nereites ichnofacies is consistent with a deep marine environment.Further identification of the Paleodictyon and Nereites sub-ichnofacies indicates a distal turbidite system setting,most likely lobe fringe.Based on the thick accumulation of FA2 and FA3 and no distinct observable vertical trend,the Early Miocene Temburong Formation in Labuan is interpreted as turbidites deposited at the fringes of lobe complexes rather than a single lobe fringe.Earlier works into the Temburong Formation in SW Labuan proposed a middle slope to proximal basin floor setting where the thin-bedded intervals were interpreted as potentially representing either levee deposits or the fringes of confined lobe deposits.Conversely,the Temburong Formation at Kampung Bebuloh exhibits characteristics of an unconfined lobe setting,suggesting an evolutionary change in depositional conditions over time.展开更多
The Luoping Biota discovered from the early Middle Triassic （Anisian） Guanling Formation of southwestern China represents a fully recovered shallow marine ecosystem, marking the end point of Early Triassic biotic re...The Luoping Biota discovered from the early Middle Triassic （Anisian） Guanling Formation of southwestern China represents a fully recovered shallow marine ecosystem, marking the end point of Early Triassic biotic recovery following the end-Permian mass extinction. Contemporaneously preserved are prolific trace fossils, which offer good opportunities to understand the palaeoecology of marine invertebrates from a fully recovered shallow marine ecosystem. Here we present a newly discovered sinuous branching burrow from the fossil-bearing unit in Member II of the Guanling Formation. Several features, including the horizontal regular sinuous nature, the branching pattern, typical H-junction, and the small wavelength/amplitude ratio of these sinuous structures within the burrow systems justify assignment of these traces as Sinusichnus sinuosus, a trace possibly produced by decapod crustaceans. Close association ofS. sinuosus with Rhizocorallium commune suggests a deposit-feeding strategy of these trace makers. The newly reported Anisian material from the Guanling Formation in Luoping represents first report of Sinusichnus from South China. The global record of Sinusichnus occurrence suggests that these burrows might have an older history than Early Middle Triassic.展开更多
Abundant aggregated, elongate, shallow borings have been discovered from the Lower Cretaceous Yixian Formation in western Liaoning, China. By contrast with several similarly-shaped trace fossils, such as Asthenopodich...Abundant aggregated, elongate, shallow borings have been discovered from the Lower Cretaceous Yixian Formation in western Liaoning, China. By contrast with several similarly-shaped trace fossils, such as Asthenopodichnium, Teredolites,Rogerella, Cubiculum and Petroxestes, their appearance, size, arranged modes, distribution density and substrate types are most similar with traces of Petroxestes that was discovered from Southern Ohio, USA（J. Paleontol. 62： 306-08,1988）. This is the first report of Petroxestes from China, and also the first report of these traces from a terrestrial environment.展开更多
Fluvial deposits from the Middle Triassic Youfangzhuang Formation in Henan Province, China contain a low-diversity trace fossils. Vertical dwelling burrows of opportunists dominate in active channel, whereas horizonta...Fluvial deposits from the Middle Triassic Youfangzhuang Formation in Henan Province, China contain a low-diversity trace fossils. Vertical dwelling burrows of opportunists dominate in active channel, whereas horizontal deposit-feeding, grazing, and vertical dwelling burrows occur in overbank deposits. Seven recurrent ichnofabrics were distingushed. The Palaeophycus tubularis ichnofabric pre- serves below scour interface between two fluvial cycles. The Skolithos linearis ichnofabric forms in middle to high-energy, soft substrates in the middle and upper parts of active channel deposits under semi-arid climate. The Skolithos linearis-Planolites montanus ichnofabric occurs in the sediments just a little above the Skolithos linearis ichnofabric and is formed in middle-energy, soft substrates in the up- per part of active channel deposits. The Planolites montanus ichnofabric is mostly preserved in associa- tion with medium- to thick-bedded brown-red silty mudstones or siltstones in low-energy, perennial muddy bottom ponds in overbank settings. The Taenidium barretti ichnofabric is interpreted as peri- odically exposed ephemeral ponds or low-energy distal floodplain. The Skolithos isp. ichnofabric com- monly occurs in middle to high-energy firm ground of proximal foodplain or crevasse-splay deposits. The root trace iehnofabric occurs in the crevasse splay deposits. The presence of thin palaeosols and the abundance of calcretization in mudstones indicate a seasonal climate ranging from humid to semi-arid, with high temperature, rainfall, and well-defined dry and wet seasons.展开更多
Many kinds of ichnofossil Zoophycos occur commonly in the carbonate rocks of Pennsylvanian to Cisuralian Taiyuan Formation in North China. In this study, carbonate microbodies types were identified in four differently...Many kinds of ichnofossil Zoophycos occur commonly in the carbonate rocks of Pennsylvanian to Cisuralian Taiyuan Formation in North China. In this study, carbonate microbodies types were identified in four differently-colored fillings of Zoophycos using scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS）. Based on the morphologic characteristics, these carbonate microbodies can be divided into three groups, i.e., spheroids, framboids and rhabditiforms. According to the structural features of surface and individual or aggregate morphologies, the three groups can be further subdivided into thirteen types： （1） smooth spheroids; （2） spheroids with tiny thorns; （3） spheroids with a finely granulated surface; （4） spheroids with a flocculent surface; （5） spheroids with a vermiform surface; （6） framboid monomers; （7） framboid colonies; （8） linear smooth rhabditiform bodies; （9） smooth rhabditiform bodies with expanding ends; （10） biserial rhabditiform bodies; （11） spiral rhabditiform bodies; （12） thorny rhabditiform bodies; and （13） branched rhabditiform bodies. This paper not only describes the morphology, composition and occurrence of the various carbonate microbodies, but also discusses their possible microbial genesis, as follows： （1） carbonate spherical microbodies most likely were generated after globular bacterial cells had been fully displaced by minerals; （2） framboid monomers and colonies corresponding to the morphology of biogenic strawberry （or raspberry） pyrite, with their appearance and internal structure possibly inheriting the morphology of microbial cells, were indirectly generated by some microenvironmental changes due to microbial activity; （3） the morphological features, size, occurrences and preservation of filamentous and rhabditiform microbodies indicate that they may be biogenic structures, and possibly mineralized microbial fossils; and （4） some kind of symbiotic relationship exists between microbial action and the Zoophycos trace-makers. Besides, the differently-colored fillings of Zoophycos are most likely closely related to differences in the composition of microbial taxa, which in turn reflect different microenvironmental conditions.展开更多
The 14^（th） International Ichnofabric Workshop was held successfully in Taipei, China from April 29 thto May 2^（nd）. From the oral presentations, posters, intra-and post-workshop field trips, and workshop discussi...The 14^（th） International Ichnofabric Workshop was held successfully in Taipei, China from April 29 thto May 2^（nd）. From the oral presentations, posters, intra-and post-workshop field trips, and workshop discussions, a few promising aspects of ichnological study can be outlined：（1） Ichnotaxonomy is, and will be the major endeavour of ichnologists, supplying important behavioural information for palaeontological studies, and also providing reasonable, objective, and convenient taxonomical framework for further sedimentological and palaeoecological studies;（2） Ichnofabric analysis is widely applied to in-depth sedimentological, palaeoclimatical, and petroleum exploration studies, offering a wealth of biological information that cannot be properly obtained from traditional sedimentological and geochemical analyses;（3） Study of trace fossils in the context of evolutionary palaeoecology sheds light on some intriguing issues of the biological responses during certain critical periods in Earth＇s history;（4）Work on combining geomicrobiology and ichnology is under way;（5） Quantitative morphological characterization has become increasingly useful in grasping the finer ingredients of functional morphology.展开更多
文摘Twenty-three ichnotaxa have been found in the Silurian and Carboniferous turbidites of the Tianshan orogenic belt and the Triassic turbidites of the East Kunlun-West Qinling orogenic belt of northwestern China. They are Acanthorhaphe isp., ?Arthrophycus isp., Aulichnites parkerensis, Chondrites isp., C. intricatus, C. targionii, Cochlichnus anguineus, coprolite, Dendrotichnium haentzscheli, Helminthopsis isp., Helminthopsis abeli, H. hieroglyphica, H. cf. irregularis, Imbrichnus isp., Kunlunichnus qinghaiensis, Laevicyclus rotaeformis, Lophoctenium tianshanensis, Megagrapton isp., Micatuba verso?, Muensteria isp., Neonereites, Palaeophycus, and Zoophycos caudagalli, two of which, namely, Kunlunichnus qinghaiensis and Lophoctenium tianshanensis, are new ichnospecies. The described trace fossils can be grouped into five ichno-assemblages: the Aulichnites-Imbrichnus ichno-assemblage representing turbidity current deposits of a restricted anoxic deep-sea basin, the Lophoctenium ichno-assemblage showing the deep-sea or ocean environments relevant to a plate subduction, the Zoophycos-Helminthopsis ichnoassemblage representing the upper-middle turbidity fan deposits of a pelagic and hemipelagic environment, the Megagrapton-Chondrites ichno-assemblage representing the middle-lower turbidity fan deposits of an oceanic archipelago and the Kunlunichnus ichno-assemblage indicating bathyal turbidity current deposits.
基金supported by National Natural Science Foundation of China (No. 41072102)the National Basic Research Program of China(No.2012CB214804)
文摘Based on the analysis of trace fossils collected from the typical outcrop of the Lower Cambrian Wusongger Formation in the Kalpin area, ten ichnospecies of six ichnogenus were identified in the upper member of the Wusongger Formation, with most of them being found for the first time. The trace fossils are described seriatim. The ichnospecies are mainly represented by such common trace fossils as Ophiomorpha nodosa, Helminthopsis hieroglyphica, Helminthopsis ichnosp., Planolites beverleyensis, Planolites vulgaris, Planolites montanus, Palaeophycus striatus, Palaeophycus curvatus, Cochlichnus anguineus and Rituichnus elongatum. The trace fossils are of high diversity and low abundance, and can be diagnosed as the Cruziana ichnofacies. They can be interpreted as having formed in a shallow water environment.
基金This research was a project (No. 4870087) supported by the National Natural Science Foundation of China.
文摘There are abundant and highly varied trace fossils in the Sinian-Cambrian boundary beds in eastern Yunnan. Collections from 27 sections and their study give altogether 45 ichnogenera and 87 ichnospecies. Among them, 2 ichnogenera and 7 ichnospecies are new, and 31 known ichnogenera and 38 known ichnospecies first found in the region. According to their order of appearance in the boundary beds and their assemblage features, the trace fossils in the Sinian-Cambrian boundary beds in the region may fall into 4 trace fossil assemblage zones in ascending order. In the paper they are correlated with those in the equivalent horizons abroad and their geological significance is discussed preliminarily.
基金supported by National Basic Research Program of China (Grant No. 2006CB80640)National Natural Science Foundation of China (Grant Nos. 40830212,40772022)
文摘Six ichnogenera,Chondrites,Palaeophycus,Planolites,Rhizocorallium,Skolithos,and Thalassinoides,were identified from the drilling cores near the Global Stratotype Section and Point(GSSP) of Permian-Triassic boundary at Meishan,Zhejiang Province.The ichnological indices,including abundance,bioturbation index,and disturbed depth of trace fossils,show two episodes of intense changes near the Permian-Triassic Boundary(PTB).Episode I occurred in Beds 25-27b when the ecologically complicate forms such as Chondrites,Skolithos,Rhizocorallium,and Thalassinoides disappeared hereafter,the bioturbation index reduced from 1-5 to 1-3,and the disturbed depth declined from 5-66 to 2-5 cm.Episode II took place at the base of Bed 33 with the disappearance of Palaeophycus and Planolites,and subsequent absence of trace fossils and bioturbation till the middle-upper part of Bed 41 when the disturbed structures reoccurred,but they are only tiny Planolites and the bioturbation index was never higher than 3 and the disturbed depth less than 4 mm.Episode I shows an intense change,corresponding to the main stage of the end-Permian mass extinction,whereas Episode II is relatively weak,corresponding to the epilogue of the mass extinction of trace makers in the Early Triassic.Subsequently,ichnofossils were dominated by surface tracks in simple ecological habit and structures.This phenomenon indicates that the Early Triassic benthonic fauna is changed from sessile benthic system to mobile benthic system after the end-Permian mass extinction.In other words,the evolution of the trace fossils across the Permian-Triassic transition had an episodic process similar to the body fossils.In addition,the change of ichnofabrics is well coincided with the negative excursion of carbon isotopes and the expansion of cyanobacteria.As the results of physical and biogenic processes,trace fossils provided unique materials for the study of the biotic and environmental events,as well as their coupling evolution through the great Permian-Triassic transition.
基金supported by the Jagiellonian University(DS funds)financial assistance for the fieldwork by DST(project EMR/ 2015/001574)financial support by the Alexander von Humboldt Foundation
文摘The uppermost part of the Upper Bathonian Sponge Limestone member, Patcham Formation, of the Jhura Dome of Kachchh Mainland is a thickening-and shallowing-upward succession topped by medium-to thick-bedded hummocky cross-stratified grainstones deposited by storm waves. Occasionally, thin, commonly lenticular, intraclastic-bioclastic silty marl intercalations between the grainstones are highly bioturbated, in contrast to the grainstones, in which, for the most part, trace fossils occur scattered. Large exposures of bedding planes of the grainstones allow the detailed investigation of ichnological features, whereas the high density of traces in the soft marls precludes the identification of any ichnotaxa. Eighteen ichnotaxa have been recorded including Ophiomorpha, Thalassinoides, Taenidium, Gyrophyllites, Chondrites, Dactyloidites, Teichichnus, Bolonia, and Ancorichnus. Except for Ophiomorpha nodosa and Thalassinoides, which generally indicate moderate to high energy conditions and are the dwelling burrows of suspension-feeding to omnivorous crustaceans, the ichnotaxa represent a deposit-feeding behaviour of their producers and thus are characteristic of low-energy environments. The trace fossils form three ichnoassemblages characterized by(1) Ophiomorpha nodosa and Thalassinoides suevicus,(2)?Thalassinoides isp. A, Taenidium, and Bolonia lata,and(3) Ancorichnus. The dominance of traces of deposit-feeders in rocks indicative of high-energy events is counterintuitive and points to their non-contemporaneity. The sediments were deposited during brief highenergy events, whereas the trace fossils were produced when, after waning of storms low-energy conditions prevailed. This time-averaging is particularly pronounced in trace fossils that extend vertically downwards and may reach strata deposited under distinctly different conditions. Thus, environmental interpretations based on trace fossils should refer to colonisation surfaces rather than to the sediment surrounding the trace fossils. In the latter case, interpretations may be erroneous, especially when erosion subsequently destroyed sedimentary evidence of their original environment.
基金The study is supported by the National Science Foundation of China （Nos. 40172014 and 40372023） and the Guizhou University Foundation, China.
文摘Over 190 specimens of an attachment ichnofossil Kailidiscus （n. ichnogen.） have been found in the Kaili Bitoa, a Burgess Shale-type biota, from the middle Kaili Formation （early Middle Cambrian） in Taijiang County, Guizhou Province, southern China. Kailidiscus is an epichnia with a circular to oval attachment platform, on which there is a carbonaceous film probably formed by the body of the living organism. Structures such as a marginal furrow, an inner and outer marginal ride, many convex fold-ridges, and a large caved peripheral furrow on the attachment platform may be the result of basal tissues of a sessile organism that wrinkled to increase the attachment＇s surface area. The Kailidiscus organism may have been a sessile cnidarian attached to the muddy seafioor. Kailidiscus organisms lived in relatively quiet water, and were buried by a sudden influx of sediment.
基金the National Natural Science Foundation of China (Grant #41872003)
文摘Two Upper Devonian to Lower Carboniferous sections,namely the Bulongguoer and Haer(Gennaren area)in the Junggar Basin,Central Asian Orogenic Belt,in northwestern China were examined with regard to ichnology and palynology.The deposits of the Hongguleleng Formation and Namu Member of the Heishantou Formation,respectively,are mostly unbioturbated or poorly bioturbated,with poorly diversified trace fossils,which indicate unfavourable conditions for the burrowing benthic community during the Late Devonian and Early Carboniferous.The main factor governing the growth of the bioturbating population was the rapid sedimentation of fine-grained,volcanic material documented as tempestites,which buried the benthic fauna.In the Bulongguoer section,the presence of miospores Teichertospora torquata and Grandispora gracilis enabled identification of the broad Teichertospora torquata–Grandispora gracilis Miospore Zone from the transitional Frasnian/Famennian interval.More accurate identification of palynostratigraphical levels(DE and CZ Miospore zones)is only tentative.On the basis of palynofacies analysis,samples from the lower Bulongguoer section indicate deposition in more proximal conditions,whereas samples from the top of the section indicate deposition in a more distal environment.In the Haer section,only a general biostratigraphic indication for the Tournaisian was possible,owing to poor preservation of organic matter.
文摘The well known Cretaceous seaway in North America was recognized in the middle of the last century and the Palaeogene seaway in East China was proposed by the author recently. The two seaways located on the opposite sides of North Pacific Ocean may be not a coincidence, and a comparative study was made in this paper. The results show that the two seaways inundated basins share several similarities particularly in basin origin, filling processes and reservoir facies. It is suggested that reservoir facies of estuarine sandstone and shelf bar sandstone related to sea level fluctuation, which are well developed in the Cretaceous seaway covered basins in North America might have been also developed here in Palaeogene seaway inundated basins in East China. Therefore it is worth paying more attention to finding these new reservoir facies on this side of the Pacific ocean. Evidences of sedimentology and ichnology indicate that good prospects are likely.
基金University Grant Commission (UGC, New Delhi), is acknowledged for providing the research grant to BPS (No.F.20-1/2012 (BSR)/20-8(12)/2012/BSR)
文摘The Lower Cambrian Nagaur Sandstone（Marwar Supergroup） has yielded trace fossils Treptichnus, Cruziana, serially repeated Rusophycus, Diplichnites, Monomorphichnus, Bergaueria,arthropod swimming traces and leap frogging marks of Cruziana ichnofacies. This ichnofossils assemblage is dominantly preserved in fine to medium grained red sandstone beds of the Mohra Member（Nagaur Sandstone）. The presence of graded rip-up clasts, current ripples, dune crossstratification with mud drapes and tidal bundles indicates a subtidal paleoenvironment for the deposition of Nagaur Sandstone Formation, which is corroborated by the Cruziana ichnofacies trace fossil assemblage.
基金Farah Syafira Burhanuddin reports financial support was provided by ConocoPhillips Company.
文摘Thin-bedded turbidites are important hydrocarbon-bearing reservoirs in many mature fields throughout the world.The type of turbidite depositional setting strongly influences vertical and horizontal continuity of the reservoir.However,distinguishing between lobe and levee associated thin-bedded turbidites remains challenging due to their generally similar facies characteristics.This study aims to contribute some insights to this problem by conducting a detailed bed-scale facies analysis on the Early Miocene Temburong Formation exposed at Kampung Bebuloh,Labuan Island,Malaysia,which may uncover features that can help in differentiating between both depositional types.Six facies are recognized in the Temburong Formation,which are interpreted as low density turbidites(F1-F4),hybrid event beds(F5),and sustained turbidites(F6).Detailed facies and ichnology analysis reveal features which are consistent with a lobe fringe deposit rather than leveeassociated environment interpretation,including tabular bed geometries,presence of hybrid event beds,and the absence of thick-bedded channel-fill sandstones.Five facies associations are identified and interpreted as representing sub-environments within an overall lobe depositional setting.A diverse trace fossil assemblage,comprising the Nereites ichnofacies is consistent with a deep marine environment.Further identification of the Paleodictyon and Nereites sub-ichnofacies indicates a distal turbidite system setting,most likely lobe fringe.Based on the thick accumulation of FA2 and FA3 and no distinct observable vertical trend,the Early Miocene Temburong Formation in Labuan is interpreted as turbidites deposited at the fringes of lobe complexes rather than a single lobe fringe.Earlier works into the Temburong Formation in SW Labuan proposed a middle slope to proximal basin floor setting where the thin-bedded intervals were interpreted as potentially representing either levee deposits or the fringes of confined lobe deposits.Conversely,the Temburong Formation at Kampung Bebuloh exhibits characteristics of an unconfined lobe setting,suggesting an evolutionary change in depositional conditions over time.
基金partly supported by the ARCDP discoverygrant to G. R. Shi (No. DP150100690)supported by a CAS Pioneer Hundred Talents Program (to ML)+2 种基金supported by a grant from the State Key Laboratory of Biogeology and Environmental Biology (No. GBL21410 to ML), China University of Geosciences (Wuhan)a grant from the National Natural Science Foundation of China (No. 41502013)supported by for China Geological Survey projects (Nos. DD20160020, 1212011140051, 12120114030601, and 1212010610211)
文摘The Luoping Biota discovered from the early Middle Triassic （Anisian） Guanling Formation of southwestern China represents a fully recovered shallow marine ecosystem, marking the end point of Early Triassic biotic recovery following the end-Permian mass extinction. Contemporaneously preserved are prolific trace fossils, which offer good opportunities to understand the palaeoecology of marine invertebrates from a fully recovered shallow marine ecosystem. Here we present a newly discovered sinuous branching burrow from the fossil-bearing unit in Member II of the Guanling Formation. Several features, including the horizontal regular sinuous nature, the branching pattern, typical H-junction, and the small wavelength/amplitude ratio of these sinuous structures within the burrow systems justify assignment of these traces as Sinusichnus sinuosus, a trace possibly produced by decapod crustaceans. Close association ofS. sinuosus with Rhizocorallium commune suggests a deposit-feeding strategy of these trace makers. The newly reported Anisian material from the Guanling Formation in Luoping represents first report of Sinusichnus from South China. The global record of Sinusichnus occurrence suggests that these burrows might have an older history than Early Middle Triassic.
基金supported by the National Natural Science Foundation of China (Grant No. 41172003 and 41572004)
文摘Abundant aggregated, elongate, shallow borings have been discovered from the Lower Cretaceous Yixian Formation in western Liaoning, China. By contrast with several similarly-shaped trace fossils, such as Asthenopodichnium, Teredolites,Rogerella, Cubiculum and Petroxestes, their appearance, size, arranged modes, distribution density and substrate types are most similar with traces of Petroxestes that was discovered from Southern Ohio, USA（J. Paleontol. 62： 306-08,1988）. This is the first report of Petroxestes from China, and also the first report of these traces from a terrestrial environment.
基金supported by the National Natural Science Foundation of China (No. 41072003)the Fostering Foundation of Henan Polytechnic University for the Excellent Ph. D Dissertation (No. 2011011001)
文摘Fluvial deposits from the Middle Triassic Youfangzhuang Formation in Henan Province, China contain a low-diversity trace fossils. Vertical dwelling burrows of opportunists dominate in active channel, whereas horizontal deposit-feeding, grazing, and vertical dwelling burrows occur in overbank deposits. Seven recurrent ichnofabrics were distingushed. The Palaeophycus tubularis ichnofabric pre- serves below scour interface between two fluvial cycles. The Skolithos linearis ichnofabric forms in middle to high-energy, soft substrates in the middle and upper parts of active channel deposits under semi-arid climate. The Skolithos linearis-Planolites montanus ichnofabric occurs in the sediments just a little above the Skolithos linearis ichnofabric and is formed in middle-energy, soft substrates in the up- per part of active channel deposits. The Planolites montanus ichnofabric is mostly preserved in associa- tion with medium- to thick-bedded brown-red silty mudstones or siltstones in low-energy, perennial muddy bottom ponds in overbank settings. The Taenidium barretti ichnofabric is interpreted as peri- odically exposed ephemeral ponds or low-energy distal floodplain. The Skolithos isp. ichnofabric com- monly occurs in middle to high-energy firm ground of proximal foodplain or crevasse-splay deposits. The root trace iehnofabric occurs in the crevasse splay deposits. The presence of thin palaeosols and the abundance of calcretization in mudstones indicate a seasonal climate ranging from humid to semi-arid, with high temperature, rainfall, and well-defined dry and wet seasons.
基金jointly supported by the National Natural Science Foundation of China(Grant No.41772104)the Basic and Frontiers Research Program of Henan Province(Grant No.162300410256)the Doctor Foundation of Henan Polytechnic University(Grant No.B2013-075)
文摘Many kinds of ichnofossil Zoophycos occur commonly in the carbonate rocks of Pennsylvanian to Cisuralian Taiyuan Formation in North China. In this study, carbonate microbodies types were identified in four differently-colored fillings of Zoophycos using scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS）. Based on the morphologic characteristics, these carbonate microbodies can be divided into three groups, i.e., spheroids, framboids and rhabditiforms. According to the structural features of surface and individual or aggregate morphologies, the three groups can be further subdivided into thirteen types： （1） smooth spheroids; （2） spheroids with tiny thorns; （3） spheroids with a finely granulated surface; （4） spheroids with a flocculent surface; （5） spheroids with a vermiform surface; （6） framboid monomers; （7） framboid colonies; （8） linear smooth rhabditiform bodies; （9） smooth rhabditiform bodies with expanding ends; （10） biserial rhabditiform bodies; （11） spiral rhabditiform bodies; （12） thorny rhabditiform bodies; and （13） branched rhabditiform bodies. This paper not only describes the morphology, composition and occurrence of the various carbonate microbodies, but also discusses their possible microbial genesis, as follows： （1） carbonate spherical microbodies most likely were generated after globular bacterial cells had been fully displaced by minerals; （2） framboid monomers and colonies corresponding to the morphology of biogenic strawberry （or raspberry） pyrite, with their appearance and internal structure possibly inheriting the morphology of microbial cells, were indirectly generated by some microenvironmental changes due to microbial activity; （3） the morphological features, size, occurrences and preservation of filamentous and rhabditiform microbodies indicate that they may be biogenic structures, and possibly mineralized microbial fossils; and （4） some kind of symbiotic relationship exists between microbial action and the Zoophycos trace-makers. Besides, the differently-colored fillings of Zoophycos are most likely closely related to differences in the composition of microbial taxa, which in turn reflect different microenvironmental conditions.
基金supported by the National Natural Science Foundation of China [grant numbers 41290260, 41472001]
文摘The 14^（th） International Ichnofabric Workshop was held successfully in Taipei, China from April 29 thto May 2^（nd）. From the oral presentations, posters, intra-and post-workshop field trips, and workshop discussions, a few promising aspects of ichnological study can be outlined：（1） Ichnotaxonomy is, and will be the major endeavour of ichnologists, supplying important behavioural information for palaeontological studies, and also providing reasonable, objective, and convenient taxonomical framework for further sedimentological and palaeoecological studies;（2） Ichnofabric analysis is widely applied to in-depth sedimentological, palaeoclimatical, and petroleum exploration studies, offering a wealth of biological information that cannot be properly obtained from traditional sedimentological and geochemical analyses;（3） Study of trace fossils in the context of evolutionary palaeoecology sheds light on some intriguing issues of the biological responses during certain critical periods in Earth＇s history;（4）Work on combining geomicrobiology and ichnology is under way;（5） Quantitative morphological characterization has become increasingly useful in grasping the finer ingredients of functional morphology.
