北京昌平青白口系痕迹化石

北京昌平青白口系长龙山组和景儿峪组发育有丰富的痕迹化石,其中长龙山组产有Ｈｅｌｍｉｎｔｈｏｐｓｉｓ ｓｐ．,Ｃｏｃｈｌｉｃｈｎｕｓ ｓｐ．,代表潮下低能环境;景儿峪组产有Ｓｋｏｌｉｔｈｏｓ ｓｐ．和Ｍｏｎｏｃｒａｔｅｒｉｏｎ ｓｐ．,代表高能潮间环境。     

Ichnofacies: a mixture of taphofacies and biofacies

The environmental significance of individual ichnofacies has become a point of debate, and the Scoyenia ichnofacies is not clearly defined. Removal of the marine/non-marine boundary from ichnofacies definitions, as well as the bathymetry control, would render the Scoyenia ichnofacies unnecessary and would consolidate the definitions of the remaining ichnofacies. The constitution of the remainder is far from uniform. In some, the characteristic features are influenced by taphonomic bias more than by ecological factors, and thus these ichnofacies are in effect taphofacies (Skolithos, Cruziana and, especially, Zoophycos and Nereites). Others, on the other hand, have a primarily ecological definition and function as biofacies (Glossifungites, Trypanites, Teredolites and Psilonichnus), taphonomic bias playing a relatively minor role. Opportunistic occurrences of Skolithos in storm deposits do not fall within the Skolithos ichnofacies sensu stricto , and may be regarded as a separate Arenicolites ichnofacies, having an ecological character. □ Trace fossils, ichnofacies, salinity.     

Environmental distribution of trace fossils in the Jurassic of Kachchh (Western India)

Summary Trace fossils occur abundantly in Middle Jurassic rocks of the Kachchh Basin. They are found in environments ranging from beach sequences down to central parts of the basin. For stratinomic reasons, they are particularly well preserved in storm deposits. Their distribution pattern exhibits a clear relationship to the hydrodynamic conditions and, secondarily, to bathymetry, and follows the classic ichnofacies concept ofSeilacher (1967). High energy nearshore areas and submarine shoals are represented by members of the Skolithos ichnofacies such asOphiomorpha nodosa, Arenicolites, Diplocraterion parallelum, andRhizocorallium jenense. The storm-influenced ramp contains both members of the Cruziana ichnofacies (e.g.Rhizocorallium irregulare, Thalassinoides suevicus, Taenidium serpentinum, Chondrites) and the Skolithos ichnofacies (in particularOphiomorpha). The former were produced during interstorm phases, the latter are of post-storm origin. Carbonate ramp environments of low to intermediate energy also contain members of the Cruziana ichnofacies, whilst equivalent siliciclastic environments are characterized by a low-diversity Zoophycos ichnofacies. Low energy basinal environments of fine-grained substrates contain an impoverished Cruziana ichnofacies consisting ofChondrites, Trichichnus andThalassinoides suevicus. 32 ichnotaxa are briefly described, among themSphaerichnus lobatus ichnogen. et ichnosp. nov.     

湖南新化下石炭统遗迹化石及其沉积环境

鉴定了产自湖南新化地区早石炭世碳酸岩沉积中的遗迹化石6属(Zoophycus, Chondrites, Phycodes, Planolites, Palaeophycus, Skolithos)16种.并根据岩性实体与遗迹化石以及沉积构造等特征,划分为2个沉积亚相、21个微相、19个遗迹相.     

山东莱阳盆地早白垩世莱阳群的遗迹化石

山东莱阳早白垩阳群自下而上分为瓦屋夼组,林寺山组,止风庄组,水南组,龙旺庄组和曲格庄组。为一套河湖相沉积,产有较丰富,分异度较高的非海相遗迹化石和兽脚类恐龙足迹化石,共鉴定出遗迹属11个,未定属1个,其中遗迹种9个,未定种2个,遗迹化石是：Cochlichnus anguines,Diplocraterion parallelun,Helminthoidichnites tenuis,Palaeophycus tubularis,Planolites montanus ,Scolica sp.,Scoyenia gracilis,Skolithos linearis,Taenidium cameromensis,Thalassinoides sp.,恐龙足迹化石是：Paragrallator yangi,这些化石按习性可分为4类,即：居住构造, 爬行迹,觅食[迹和牧食迹,其中又以前3种为主,遗迹化石在剖面上的分布不均匀,以上部的水南组,龙旺庄,曲格庄3个组最丰富。     

On stratigraphic subdivision of hominoid fossil localities of Yuanmou,Yunnan

There are four hominoid localities in the Yuanmou basin. There is no appreciable difference of fossil mammals collected from them respectively. On the other hand, judging from the occurrence of the strata and the characteristics of the deposits as well as from the trace of the neotectonics, the “homo layers” are identical to “Ramapithecus layers” in their occurrence. Thus the Hominoid fossils are exactly the same age.     

机会（r—选择）和均衡（Ｋ—选择）遗迹化石的现代生态学解释

介绍地质记录中在不稳定的沉环境下,由于生活条件的恶化（盐度的变,严酷的温度,低含氧量及移动的沉积基底等）以及沉积事件（浊流沉积和风暴沉积）所产生的机会(r-选择）遗迹化石和均衡（Ｋ－选择）遗迹化石及其特点以及机会行为方式的古生物证据。对现代底栖生物的生态学研究,揭示现代机会生物均衡生物的生态特征（居群策略）描述由于破坏事件导致动物群消除后重新移居的现代实例,有助于了解地质记录中机会(r-选择）遗迹化石和均衡（Ｋ－选择）遗迹化石的成因及其古生态特征。     

Infaunal communities and tiering in Early Palaeozoic nearshore clastic environments: trace-fossil evidence from the Cambro-Ordovician of New South Wales

Understanding of the palaeoecology of Early Palaeozoic shallow-marine communities in sandy habitats is incomplete. Reasons for this include the poor preservation of body fossils and the dominance of Skolithos piperock in sandstones of that age. Cambrian and Ordovician deposits preserving diverse nearshore trace-fossil assemblages are therefore of critical importance for assessing the early evolution of marine ecosystems. The basal part of the Cambro-Ordovician Bynguano Formation of the Mootwingee area (New South Wales, Australia) is a series of interbedded sandstones and mudstones, which were deposited under nearshore conditions. These strata provide an early example of the Arenicolites ichnofacies. Two ichnocoenoses are distinguished in the sandstones of this unit. A 'predepositional' ichnocoenosis, which reflects the benthic community prior to episodes of sand deposition, includes dense aggregations of Rusophycus with rare Planolites. The 'postdepositional' ichnocoenosis is more diverse and includes Thalassinoides, Arenicolites (various types), Monocraterion, Skolithos, Trichichnus , and epichnial grooves. The tiered structure developed in this ichnocoenosis is preserved as a 'frozen tiered profile' and is characterised by a Thalassinoides tier, 10–30 cm in depth, which is cross-cut by Skolithos and Arenicolitesin the middle tier, and by Arenicolites and Trichichnusin the shallowest tier. The pattern of tiering indicates that a complex ecosystem of opportunistic organisms, capable of exploiting shifting substrates, had evolved by the earliest Ordovician. □ Predepositional, postdepositional frozen tier profile, ichnocoenosis, nearshore clastics, RUSOPHYCUS, Cambro-Ordovician, Bynguano Formation, Mootwingee, New South Wales.     

河南泌阳凹陷古近纪核桃园组遗迹化石组合及其环境意义——兼论深水湖泊遗迹相特征

南襄盆地泌阳凹陷古近纪核桃园组湖泊沉积中发育大量遗迹化石,含5个遗迹组合,形成于从滨湖到深湖的不同沉积环境中。Taenidiumserpentinum遗迹组合反映稍有覆水并周期性暴露的低能滨湖环境;Skolithos linearis遗迹组合代表湖泊中上临滨环境;Planolites montanus遗迹组合与低能浅湖环境有关;Skolithos verticalis遗迹组合形成于浅湖的远源风暴沉积中;Semirotundichnus dongyingensis遗迹组合发育在贫氧的半深湖-深湖沉积环境中。     

塔里木盆地晚泥盆世东河塘组河口湾相遗迹化石

河口湾具有特定的环境条件和沉积组成,其遗迹化石具有半咸水沉积的遗迹群落特征。描述和分析塔里木盆地塔中4井区上泥盆统东河塘组河口湾沉积中的遗迹化石和生物扰动构造后,发现3类遗迹组构,其中Ophiomorpha遗迹组构发育在纯净砂岩中,与河口湾潮汐砂坝有关;Skolithos遗迹组构发育在薄层砂岩中,与河口湾砂坪有关;Palaeophycus遗迹组构发育在泥岩中,与河口湾泥坪、砂泥坪有关。     

Ichnological and Sedimentological Characteristics of Submarine Fan-Delta Deposits in a Half-Graben,Lower Cretaceous Palnatokes Bjerg Formation,NE Greenland

Fault-scarp related fan deltas developed in tilted half grabens in NE Greenland during late Jurassic—early Cretaceous rifting. This study documents ichnological and sedimentological characteristics of the Lower Cretaceous interval of a submarine fan-delta succession (Palnatokes Bjerg Formation, Wollaston Forland), which represents a time of waning rift activity and transgression. For this purpose, two variably exposed ca. 150 m-thick sections were studied ～10 km from the coeval fault scarp, near the axis of the most proximal fault block. Moreover, an additional ～20 m thick coeval succession was studied in the next fault block ～20 km from the coastline defining fault. The results indicate deposition on the basin floor, in the distal fan and in a mid-fan channel-overbank/splay complex of a subaqueous fan delta. The deposits are characterized mainly by various facies of high and low density turbidity currents, hybrid event beds, and transitional flow facies that grade upward into sediment starved basinal mudstones. The ichnological pattern recorded in these strata is strongly mixed, frequently containing elements of the impoverished Skolithos, Cruziana, Zoophycos ichnofacies, and more rarely of the Nereites ichnofacies. Characteristic features also include suites dominated by infaunal locomotion and feeding trails (including the “Curvolithus suite”) and the common occurrence of crustacean burrows. The results are indicative of a depositional system resembling a fjord-side delta that differs sedimentologically and ichnologically from many other gravity-flow systems of similar grain-size caliber. The ichnological pattern recorded in these strata is potentially a characteristic feature of the subaqueous fan-deltas in comparable settings, reflecting the distinct basin physiography with an abrupt change in bathymetry, a narrow basin geometry, and environmental stress resulting from unstable physical conditions. The counter slope of the rotated fault block may explain the common signs of flow concentration and abrupt fan termination.     

川西南峨眉山地区上白垩统夹关组遗迹组构特征及其环境意义

川西南峨眉山地区上白垩统夹关组由一套厚层到块状中、细砂岩组成,夹有少量粉砂岩和泥岩,底部有砾岩。本组地层中发育有丰富的遗迹化石,共识别出9属11种。根据遗迹化石的分布情况,划分出了5种遗迹组构,即:Palaeophycus遗迹组构、Arenicolites遗迹组构、Skolithos遗迹组构、Planolites遗迹组构和Scoyenia遗迹组构;结合它们所分布岩层的沉积特征,认为前三者分别分布于河流环境中水动力强的边滩下部、水动力中等到较强的边滩中上部和边滩向堤岸过渡的环境,后两者分布于水动力较弱的天然堤环境。     

Trace fossils in middle to late triassic fluvial redbeds,pranhita‐godavari valley,south India

Several morphological varieties of trace fossils abound in Middle and Late Triassic fluvial redbeds in the Pranhita‐Godavari Valley, south India, including Skolithos, Palaeophycus, Taenidium, escape burrows, and a type of trace very similar to ‘small stuffed burrows’ from the Triassic of Greenland. Burrow morphology was influenced by local hydrodynamic conditions. The distribution of burrows was facies controlled; some forms are restricted to channel deposits whereas others occur only in floodplains. Vertical dwelling burrows (Skolithos) occur in both channel and floodplain deposits. Horizontal structures representing deposit feeding (Taenidium) are confined to nondepositional surfaces within parallel‐laminated sandstones having parting lineations that represent catastrophically emplaced sand‐sheets in channels and proximal floodplains. Vertical escape burrows are confined to what were slowly but continually accreting parallel‐laminated sands of channel bars. Horizontal dwelling burrows (Palaeophycus) and ‘small stuffed burrows’ are virtually restricted to the smaller sandsheets of floodplain drainage systems.

The burrow assemblages do not occur as recurrent associations throughout the redbed sequence, and variations in different stratigraphic levels seem to be controlled by minor differences within a broadly similar environment. The entire assemblage has components of both the Scoyenia and Rusophycus ichnocoenoses reported from East Greenland but may be considered as the Scoyenia ichnofacies characteristic of redbeds deposited in extensive floodplains dissected by small streams, even though no Scoyenia individuals are present.     

Deep-water trace fossils in the Ilfjellet rift basin (Middle Ordovician), central Norwegian Caledonides

The late Early to early Middle Ordovician Fjellvollen Formation, Central Norwegian Caledonides, is a part of the Ilfjellet Group volcano-sedimentary succession formed in a rift basin that opened along the Laurentian margin. Depositional facies and trace fossils indicate the Nereites ichnofacies, typically found in distal turbidites and deep marine deposits. The recovered trace fossils include ?Alcyonidiopsis, Chondrites, Dictyodora, Gordia, Helminthoidichnites, Macaronichnus, Monomorphichnus, Nereites, Oikobesalon, Palaeophycus, Protovirgularia and Treptichnus. No body-fossils have been reported from the Fjellvollen Formation, but the trace fossils indicate the presence of varied epi- and infaunas of arthropods, bivalves, gastropods and polychaets. The abundance of meandering and looping trace fossils is comparable to what is found in the inferrably time-equivalent Vuddudalen Group farther north, although lack of graphoglyptids like Megagrapton in the Fjellvollen Formation may indicate more proximal, unstable depositional conditions in fan-fringe and adjacent basin-plain settings.     

Trace fossils and their environmental significance in Dinantian carbonates of Belgium

Dinantian carbonates of the Tournai and Dinant regions, southern Belgium, contain several trace fossil assemblages. These assemblages consist of the following ichnogenera:Cruziana, Rhizocorallium,Scalarituba, Scolicia, Skolithos, Phycosiphon, Planolites andZoophycos. Scalarituba andPhycosiphon are reported for the first time from the Carboniferous of Western Europe. The ichnofossils occur in discrete ichnofacies.Skolithos andZoophycos ichnofacies occur within the Ivorian (Upper Tournaisian). TheCruziana andSkolithos ichnofacies are found in the Moliniacian (Lower Visean). In the Dinant region, ichnofossils record a change from infauna to epifauna at the Ivorian-Moliniacian transition. Woodgrained chert is recognized and corresponds stratigraphically and palaeogeographically with those from the Western Interior United States.     

Controls on trace fossil diversity in an Early Cambrian epeiric sea: new perspectives from northwest Scotland

The Lower Cambrian Eriboll Formation of northwest Scotland is renowned for the high density, low diversity trace fossils (Skolithos ichnofacies) found in its upper Pipe Rock Member. Ichnofabric analysis of the member indicates that relatively small examples of Skolithos terminating at the same foreset boundary were formed during a brief colonization window after a single depositional event, that particularly long Skolithos specimens are equilibrichnia, and that palimpsests of Skolithos represent the marginal, slightly deeper water fringes of the Pipe Rock Member depositional environment. Nearest neighbour analysis, however, suggests that such palimpsests were uncommon. A much more diverse trace fossil assemblage is present in the overlying Fucoid Member (An t‐Sròn Formation), comprising Cruziana barbata, Dactylophycus, Didymaulichnus, Halopoa imbricata, ?Margaritichnus, Monocraterion, Monomorphichnus, Palaeophycus striatus, P. tubularis, ?Phycodes, Planolites montanus, ?Polarichnus, Rusophycus ramellensis, ?Psammichnites, Skolithos and various unidentified traces, and represents the Cruziana ichnofacies. Above the Fucoid Member, the Salterella Grit Member ichnofauna is more impoverished, yielding only Cruziana, Monocraterion, Rusophycus, Skolithos and ?Spirophyton. The ichnological variations between the Pipe Rock, Fucoid and Salterella Grit members are interpreted as being driven by changes in sea level. The low trace fossil diversity in the Pipe Rock Member indicates opportunistic colonization of laterally extensive, shoreface sediments deposited by regular influxes of terrigenous material, which were overlain by more distal, ichnologically diverse sediments (Fucoid Member) as sea level rose. A minor regression then caused an increase in terrigenous sediment input, producing an impoverished, proximal Cruziana ichnofacies (Salterella Grit Member).     

天山和昆仑—秦岭造山带志留系、石炭系和三叠系复理石相遗迹化石

在天山志留系,石炭系和东昆仑－西秦岭三叠系浊积岩系中遗迹化石发育,经研究计有：Helminthopsis hieroglyphica,Neonerietes biserialis.,N,uniserialis,palaeophycus isp.,P.serratus,P.striatus.P.tubularis,Paleodictyon imperfectum,Phycodes circinnatum,Phycosiphon incertum,Planolites annularis,P.beverleyensis,P.Montanus,Rhizocorallium ips.,Scalarituba missourensis,Skolithos ips.,?Spirorhaphe isp.,sublorenzinia ips.Tambia isp.,Taphrhelminthopsis auricularis,Teichichnus isp.,Thalassinoides isp.它们构成4种遗迹化石组合：Phycosiphon-Palaeophycus组合,Neonereites-Scalarituba组合,Paleodictyon组合和Phycodes Skolithos组合,分别代表局限缺氧深海盆地浊流沉积,半深海环境中－上扇沉积,多岛洋环境的中－下扇沉积,半深海环境的中扇浊流沉积。     

Trace fossil associations related to facies of an upper Ordovician low wave energy shoreface and shelf, Oslo-Asker district, Norway

Three trace fossil associations have been identified from facies interpreted as low wave energy upper, middle and lower shoreface deposits, transitional shoreface/shelf deposits and open epicontinental shelf deposits. These were developed in pre-regressive, regressive and transgressive phases associated with eustatic sea level changes caused by the upper Ordovician glaciation. The three associations are the Skolithos-Diplocraterion association, the Diplichnites-Phycodes association and the Thalassinoides association. The Skolithos-Diplocraterion association inhabited upper, middle and lower shoreface environments, the Diplichnites-Phycodes association a lowermost shoreface environment and the Thalassinoides association inhabited offshore epicontinental shelf environmcnts. The Skolithos-Diplocraferion and Diplichnites-Phycodes associations bear strong affinities with previously described Skolithos ichnofacies assemblages (indicating shoreline environments) and the Cruziana ichnofacies forms (indicating shallow water environments down to wave base) respectively. The Thalassinoides assemblage, however, closely compares with assemblages described from Mesozoic epicontinental shelf sequences. Trace fossil diversity achieves a maximum in the lowermost shoreface environment and reduces in deeper water and shallower water environments. This accords with diversity patterns identified in analogous Jurassic epicontinental palaeonvironments. The stratigraphic distribution of some trace fossil association boundaries accords with those of contemporary body fossil associations. However, several body fossil associations are included within the volume of distribution of a single trace fossil assemblage. □ Trace fossil association, shoreface and shelf, Oslo district, upper Ordovician.     

Stellavelum arborensis igen., sp. nov., Stellavelum uncinum igen., isp. nov. and Termitichnus namibiensis isp. nov.; New Ichnofossils from Cenozoic deposits of Namaqualand,South Africa

Three new ichnotaxa are described from Cenozoic paralic to continental sediments on the west coast of South Africa. Stellavelum arborensis and Stellavelum uncinum are assigned to a mixed Skolithos and Cruziana ichnofacies and Termitichnus namibiensis is assigned to the Termitichnus ichnofacies. An interpretation of the sedimentary record shows that the Stellavelum trace makers were probably sediment ingesting annelids that lived in dense colonies in sheltered lagoonal environments during Neogene times. The Termitichnus namibiensis trace fossils are interpreted as actively backfilled termite nests which form an early to mid‐Pleistocene palimpsest, terrestrial ichnofabric which is superimposed on the older marine sediments.