A 25-m thick transgressive systems tract in the Sant Llorenc: del Munt, wave-influenced, fan-delta system (Eocene, SE Ebro Basin) has an internal framework consisting of a cluster of transgressive erosion surfaces, each of which has minor relief and which are collectively stacked vertically no more than two metres apart. Each erosion surface bounds a cycle containing a conglomeratic lag (up to 0.5-m thick) followed by a coarsening-upward sandstone to conglomeratic unit (the uppermost levels of which can be nonmarine). Individual cycles become entirely nonmarine landwards of the termination of the basal-bounding erosion surface, whereas they thin and eventually become entirely marine basinwards.The individual erosion surfaces within the transgressive tract, some 16 of them within a 20-m thick lithosome, are interpreted as wave-ravinement surfaces that repeatedly eroded into the conglomeratic shoreface during transgression. This interpretation, rather than one invoking nonmarine flooding or other marine erosion surface types, is consistent with the arrangement of bivalve and sponge borings on the top surfaces of clasts and with the associated lag pavements. Multiphase boring around the entire surface of clasts, as well as erosion of the clasts at some horizons, particularly in reaches of the tract where the ravinement trajectory is subhorizontal, suggest repeated reworking of previously generated lag pavements in zones of minimal aggradation during transgression. Where the transgressive shoreline trajectory rises more steeply and there has been more rapid aggradation during transgression, the lag pavements show only single-phase borings, with the borings on the upper surface of the pebble-pavement only.The close spacing of erosion surfaces within the transgressive systems tract, together with estimates of time span in the tract, suggest that transgressive erosion occurred with a frequency of less than 500 years. (C) 2000 Elsevier Science B.V. All rights reserved.

A different approach to the naming of trace fossils is advocated. The primary ichnotaxobase should be the form of the burrow actually occupied, and the secondary ichnotaxobase should be the morphology of the structure that reflects the manner in which this burrow has been displaced and/or extended. Only by attempting to name trace fossils in this way will it be possible to eliminate features due to sedimentological factors that took place on termination of the animal's activities, including passive infill and diagenesis. To discriminate between different preservational states the citation should include both the taxonomic and preservational aspects.

The sedimentology and sequence stratigraphy of the Upper Jurassic (Upper Oxfordian - Middle Kimmeridgian) Fulmar Formation of the Kittiwake Field, Western Platform of the north Central Graben are investigated through an integrated study of core material and wireline logs. The Fulmar Formation, in this area, comprises largely fine-grained sandstones which are intensely bioturbated such that the use of primary sedimentary structures for the identification of depositional environments is impractical. By using the approach of ichnofabric analysis presented here, the information provided by trace fossils can be fully utilized in the formulation of a depositional model for the Fulmar Formation.A depth and substrate-related succession of ichnofabrics was determined for the Fulmar Formation from more complete and progradational successions. This attached shoreface succession extends from a Chondrites ichnofabric (offshore), through Anconichnus (upper offshore), Anconichnus and spreiten burrows and 'Teichichnus zigzag' (upper offshore-offshore transition zone), bivalve tube ichnofabric (offshore transition zone to lower shoreface), Ophiomorpha irregulaire (lower shoreface), Ophiomorpha nodosa (middle shoreface) to a burrow mottling ichnofabric and associated high-energy laminated sandstones (upper shoreface). Anomalies in this succession form the basis for the identification of bounding surfaces, particularly omission surfaces (Thalassinoides and Diplocraterion habichi ichnofabrics) and sequence boundaries.The distribution and evolution of the essentially retrogradational succession of the Fulmar sandstones is illustrated by analysis of a detailed core log of well 21/18-3, a general cross section through the Kittiwake Field and an Early-Mid-Kimmeridgian time slice facies distribution map.

Attribution of burrows in the Wealden Group of southern England to Ophiomorpha is rejected. The burrows are essentially cylindrical, unlined and with a meniscate fill. Any outer knobbly appearance is due to diagenetic poikilotopic cementation or to differential weathering of a mudchip-sand fill. The variable nature of meniscare fill reflects passage of the producer through the thin-bedded, alternating sand-mud sediments or along sand-mud interfaces. The burrows are assigned to Beaconites, though, since the identity of this ichnotaxon has been questioned, reference is also made to Taenidium. Two ichnoassociations are recognized: (1) a Beaconites antarcticus-Scoyenia (or Taenidium-Scoyenia) association (Weald Clay) of a marginal lacustrine situation with fluvial input, and (2) a Beaconites barretti-Planolites (or Taenidium-Planolites) association of the fluvial (lacustrine delta) of the Lee Ness Sandstone (Ashdown Formation). The Wealden burrows offer no inherent indications of palaeosalinity, and inferences made on supposed occurrences of Ophiomorpha in the Wealden Group must be reassessed. Other occurrences of Ophiomorpha in non-marine facies are questioned. (C) 1995 Academic Press Limited.

The sixth Lyell meeting of the Geological Society was held on 13 February 1992. Major themes included advances in the study of trace fossils with emphasis on ichnofabrics, and the use of skeletal accumulations (shell and bone beds), both in elucidating environmental change, and in sequence stratigraphy. Of the 12 papers read at the meeting, seven are published in this thematic set. The papers presented cover topics which Lyell did not himself discuss at any length, with the exception of his classic study on the Temple at Puzzuoli. Nevertheless the theme of the meeting was aptly expressed by him: ‘Arrangements of fossils in strata: Each stratum in fact however far it may now lie beneath the surface was once in the state of shingle, loose sand or soft mud at the bottom of the sea, in which shells and other bodies easily became enveloped. By attending to the nature of these remains we are often enabled to determine whether deposition was slow or rapid, whether it took place in a deep or shallow sea, near the shore or far from land, and whether the water was salt, brackish or fresh’ (Elements of Geology, Chapter 3). As well as honouring Lyell it was befitting to remember Robert W. Frey (University of Georgia, Athens) who died on 1 January 1992 following a long fight against cancer. Much of his considerable research output was directly in the fields covered at the meeting. Over the past 20 years he pioneered the study of animal-sediment

In an attempt to interpret Ophiomorpha ichnofabrics observed in core, three ichnofabrics are described from outcrops where O. nodosa is a conspicuous element. These ichnofabrics enable sandy shoreline sedimentary environments to be characterized and differentiated: (1) shoreface with mottled- Ophiomorpha—Planolites ichnofabric generally without primary lamination; (2) offshore tidal shelf sand wave facies with Macaronichnus-Ophiomorpha ichnofabric associated with primary, mainly cross-laminated or cross-bedded sands; (3) estuarine facies with Ophiomorpha ichnofabric associated with primary lamination and, commonly, heterolithic sands and mudstones. Distinctions between the ichnofabrics are attributed to differences in primary stratification, the total ichnocoenoses, morphological features (such as burrow attitude, shaft restriction, pellet wall lining), to the nature of the substrate and, particularly, to the time available for colonization (larval settlement or relocation) and burrow construction, referred to here as the colonization window The analysis is applied to an interval of core (Upper Jurassic, Central Graben, North Sea) and a sequence in Eocene sediments in southern England.

The fabric of often intensely mottled, upper offshore to lower shoreface siliciclastic sediments of post-Paleozoic age is analyzed and the principal trace described from material collected from outcrop (U.K.) and the North Sea Basin (core). The characteristic trace of these mottled zones is Anconichnus horizontalis, which is a narrow, discontinuous, twisting, muddy fecal string within a poorly defined burrow fill depleted in mud and inertinite. This trace formed endogenically, principally in association with small-scale cross-stratification and thin (cm) event beds. Seven taphonomic-sediment associations (ichnofabrics) are recognized: (1) in siltstone to very fine-grained sandstone in thin (cm) event beds, often as only one trace; (2) in association with small-scale cross-stratification; (3) in dense concentrations in fine-grained sediment where the primary structures have been obscured; (4) similar to (3) but with a patchy distribution of the trace; (5) siltstone to very fine-grained sandstone, often associated with heterolithic stratification, with a higher ichnodiversity, including Phoebichnus, Palaeophycus, Thalassinoides, Rhizocorallium, Cylindrichnus and Diplocraterion; (6) as (3) but with muddy patches and sand-filled Chondrites sp.; (7) mud dominated, with silty horizons and associated with Terebellina. Associations 1 to 4 were produced by opportunistic shallow tier burrowers penecontemporaneous with deposition of mud-depleted event beds in an offshoremore » environment. Association 5, with diverse, later mid-tier burrowers, suggests a more equilibrium endobenthic community in aggrading sedimentation conditions, under fair weather, in the offshore transition zone to lower shoreface, while associations 6 and 7 indicated muddier offshore situations.« less

Geological JournalVolume 26, Issue 1 p. 92-93 Book ReviewFree Access Dinosaur tracks and traces edited by D. D. Gillette and M. G. Lockley, Cambridge University Press, 1989. No. of pages: 454. Price: £35 ($54.50) (hardback) J. E. Pollard, J. E. PollardSearch for more papers by this author J. E. Pollard, J. E. PollardSearch for more papers by this author First published: January/March 1991 https://doi.org/10.1002/gj.3350260108AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume26, Issue1January/March 1991Pages 92-93 RelatedInformation

In the past decade trace fossils have been recorded extensively from coal-bearing sediments, differing widely in facies, age and location. Westphalian or Stephanian 'coal-measures' in Britain, Europe and Eastern Canada contain an ichnofauna produced by invertebrates and/or vertebrates in upper delta plain sediments. This contrasts with the marine-related lower delta plain ichnofaunas known from Pennsylvanian rocks of the United States and Permian Gondwana 'coal-measures' of South Africa. Deltaic complexes of Middle Jurassic age in the North Sea basin and Upper Cretaceous age in North America contain marine trace fossils and dinosaur footprints in coastal coal-bearing facies. These case histories illustrate the importance of trace fossils both in facies analysis of coal-bearing sequences and in recording the presence of animals rarely known as body fossils in such clastic sediments.

ABSTRACTThe commonest arthropod trace fossils from Triassic aquatic red beds are the bilobate tracesIsopodichnusand trackways known as‘Merostomichnites’ triassicus. These trace fossils were probably produced by notostracan branchiopods, similar toTriops.Four arthropod ichnocoenoses from Lower Triassic fluvial sandstones have been analysed in terms of size frequency distribution, behavioural variation and relationship to sedimentary structures and depositional environment. OneIsopodichnusichnofauna associated with flute moulds (Dumfries-shire, Scotland) shows a normal age-structured population of arthropods responding with strong rheotaxis within shallow fluvial channels. The secondIsopodichnusassemblage associated with ripple marks (Worcestershire, England) also shows strong rheotaxis but is bimodal in size and morphotype, possibly suggesting change in arthropod behaviour with age. Two ichnocoenoses of trackways with less pronounced rheotaxis associated with ripples (Cheshire, England) and flute moulds (Württemberg, Germany) were produced by larger arthropods than the resting traces. These arthropods probably possessed 6 to 9 pairs of walking limbs.The conclusions derived from these notostracan trace fossils are compared with data on palaeoecology, population size-frequency, morphology and behaviour ofTriops cancriformisderived from the analysis of three Triassic body fossil faunas and literature on living populations. Taxonomic consideration favours retention of the nameIsopodichnusbut the trackways should be included inAcripesMatthew. Brief review of late PalaeozoicIsopodichnusassemblages which appear to predate known notostracan fossils is inconclusive as regards both identifying producers or infallible means of separation fromCruzianaassemblages.

The presence of the “Rhaetic”, now the Penarth Group ([Warrington et al. 1980][1]), in the Gribun district of western Mull was established in 1920 ( Summ. Prog. Geol. Surv. for 1920 ; Summ. Prog. Geol. Surv. for 1921, p. 35 ) following the discovery of a bivalve fauna including Rhaetavicula ( Pteria ) contorta (Portlock) and Chlamys ( Pecten ) valoniensis (Defrance) in beds exposed principally in the vicinity of Balmeanach Farm [NM 448 330]. The Penarth Group is approximately 12 m thick in the Gribun area (Lee and Bailey 1925) and comprises dark grey sandy limestones and calcareous sandstones and siltstones with some beds of yellow calcareous sandstone and dark grey and black shales. The principal section is to the east-north-east of Balmeanach Farm in the course of Allt na Teangaidh, above its confluence with the Allt Ruadh, where up to 9 m of the sequence is seen in discontinuous exposures. The base and top of the group are not exposed. The beds were assigned to the “zone of Pteria contorta” on the basis of the bivalve fauna recovered largely from exposures in that section (Lee and Bailey, op. cit.; Bailey and Anderson 1925; Lee and Pringle 1932). No further palaeontological work on the Penarth Group of Gribun has been published and the study reported here was carried out with the object of enhancing the palaeontological documentation and the biostratigraphic interpretation of those beds. Palynology Samples were collected by one of us (J.E.P.) from exposures of the Penarth Group in Allt na Teangaidh (Fig. 1) and were processed by the British . . . [1]: #ref-10

In the Silesian rocks of the Central Pennine Basin three types of ancient delta sequence are recognized Each contributed to the progressive filling of the Basin and to the gradual development of fluvialparalic conditions in Westphalian time The turbidite fronted deltaof the lowest Namurian of the Pendleian Stage of theSkipton area in the north of the Basin shows three depth related sedimentary associations which correspond with overlapping but distinct trace fossil assemblages The Thrbidite Association contains a Rhizocorallium Planolites Bergaueria assemblage on thebase or top of thin bedded turbidites the Slope Association consists of Lophoctenium and Curvolithus in laminated sandstones and siltstones and the Delta Top Association is characterized only by Monocraterion Skolithos and Pelecypodichnus in parallel bedded and cross bedded sand stones The Thrbidite and Delta Slope Associations appear to belong to theZoophycos ichnofacies of Seilacher 1967 and the Delta Top to the Cruziana and Skolithos ichnofacies Deltaic deposition thus advanced into water afew hundreds of meters deep probably of nearly fully marine salinity Trace fossils of the deeper water Nereites ichnofacies are lacking Sedimentological factors such as energy level substrate and food supply rather than bathymetry alone may have influenced the distribution of trace fossils In the south of the Basin the later Lower Kinderscoutian delta is similar sedimentologically to that of the Pend1eian but is devoid of trace fossils except for Planolites and Pelecypodichnus assemblages in the upper part of the delta slope and on the delta top The absence of trace fossils with obvious marine affinities is consistent with the interpretation that in intervals between marine inundations basin water was less saline than it was in the Skipton area during Pendleian time During the Upper Kinderscoutian Marsdenian and Yeadonian stages the Central Pennine Basin was filled mainly from the north and east by shallow water sheet deltas and by two shallow waterelongate deltas from the west Trace fossils in the delta plain sediments contain assemblages which can be assigned to theCruziana or rarely Zoophycos ichnofacies together with a variety of facies crossing forms They show progressive colonization of the delta top paleoenvironments They also suggest evolution of certain animal groups during this time Thus bivalve escape shafts attributed to cf Sallguinolites a marine genus in the Upper Kinderscoutian show a steady increase in vertical extent or height throughout the period By late Marsdenian time they were evidently formed by the non marine genus Carbollicola On independent evidence Carbonicola appears to have evolved from the bivalves which made the earliest escape shafts Lower Westphalian sediments indicate a gradual increase upwards in fluvial and swamp dominance of theextensive delta top This is well substantiated by trace fossils as far as they have been studied They playa significant part in elucidating the general sedimentary environment for instance Pelecypodichllus escape shafts suggest seasonal flooding as a result of monsoonal condition in the west Lancashire coalfield Xiphosurid traces Kouphichnium and Limulicubiclmus which range from the Marsdenian upwards provide insights into the more ephemeral aspects of sedimentation and paleoenvironments Freshwater arthropod traces and vertebrate footprints Scoyenia ichnofacies are poorly known in theWestphalian of the Pennine area when compared with the roughly contemporary ichnofaunas of Nova Scotia Canada but such traces occur in the latest Silesian and early Permian rocks in other areas of Britain

I wish to emphasize the im portance of trace fossil evidence in studying the terrestrialization of invertebrates. Associations of trace fossils of arthropod origin are known from the late Silurian and Devonian non-marine sediments in the Welsh Borders, Scotland (Midland Valley and Orcadian basins), Norway (Ringerike and Hornelen basins), Spitzbergen, Appalachians of North America and Antarctica (Pollard et al . 1982, figure 15; Pollard & W alker 1984, figure 3).

Study of a lacustrine—fan delta succession in a marginal tract of Hornelen Basin shows that occasional lakes were infilled by marginal accretion and progradation of the adjacent fluvial system. The lake deposits are dominantly thin graded rhythmites and thicker massive fine sandstones,both of great lateral extent and formed by fine sediment gravity flows. Wave-generated ripple lamination is also very common whereas current, especially climbing-ripple lamination occurs increasingly towards the southern edge of the lake. Much of the lacustrine sequence is contorted, convoluted or deformed to a lesser degree. Trough cross-stratified sandstones and pebbly sandstones characterised the lowsinuosity stream systems which fed the lakes from the south. In a narrow transitional zone, interpreted in terms of high-sinuosity distributary channels and shoreline, there are significant amounts of planar cross-strata as well as ripple and plane parallel lamination. Eight distinct types of trace fossils, chiefly arthropod tracks, trails and burrows (Scoyenia ichnofacies) are present in the fine sediments (mudflats, pools and low bars) of this latter zone. Behaviour patterns are dominantly locomotion and resting traces, possibly with some surface feeding but an absence of infaunal feeding or dwelling structures.

SUMMARY In a facies and trace fossil analysis of the Waterstones in North Cheshire, five gradational lithofacies are recognised: A—discontinuous bodies composed of lenticular units of cross-bedded, medium to fine sandstone: B—thin-bedded, muddy, fine sandstone with interbedded shale: C—thinner sandstones interlaminated with flaser-bedded siltstone or mudstone: D—shale: E—silty mudstone (‘marl’). Trace fossils described are: Thalassinoides cf. suevicus, Diplocraterion luniforme, Arenicolites sp., cf. ‘ Scoyenia?’ triadica, Planolites, Isopodichnus, looped trails and vertebrate footprints. This ichnocoenosis can be assigned primarily to the Skolithos — Glossifungites ichnofacies, which represents the earliest stratigraphical evidence of marine conditions so far described from the English Trias. The Scoyenia ichnofacies is represented also. The depositional environment was intertidal. Various sub-environments are recognised: lower and middle intertidal sandflat (lithofacies B and C), high intertidal mudflat to possibly impersistent sabkha (lithofacies E) and sand bars in tidal flat channels (lithofacies A). This interpretation supports the importance of the Röt marine transgression in the Waterstones and suggests general regression into the overlying Keuper Marls.

Synopsis Study of a 45 m succession of the Auchenhew Beds (Triassic) of western Arran, with a record of halite pseudomorphs, symmetrical ripple marks, flaser, wavy and lenticular bedding, bimodal palaeocurrents and particular vertical arrangements of lithologies and structures, has provided evidence of intertidal conditions, probably within the context of a relatively arid, low energy, muddy shoreline. The new observations lend support to earlier suggestions of a marine connection and influence at this time and necessitate some reconsideration of the environmental significance of trace fossils previously described from this area.

Synopsis The first identifiable trace fossils recorded in the Permo-Triassic of Arran come from an exposure within the Auchenhew Beds near King’s Cave on the west coast. The forms cf. “Siphonites”, cf. Cylindricum and epichnial burrows, preserved in micaceous sandstones and mudstones, indicate the activity of an ephemeral invertebrate, probably arthropod, fauna in a shallow fluvial-lacustrine environment of unknown salinity. These trace fossil bearing sediments occur in a regional sequence of facies indicating an upwards change in environment from fluvial through aeolian and fluvial-lacustrine to marine.

Summary Small isolated lenses of algal limestone discovered at the junction of the Etruria Marl and Newcastle Group in north Staffordshire contain algae of the genera Girvanella, Ortonella, Garwoodia and Bevocastria associated with Anthraconauta, ostracods, Spirorbis and plant fragments. The lenses represent preservation in situ of sediment formed in temporary pools rich in calcium and other carbonates. The algae grew as thin crusts and small colonies in these saline pools before the deposition of the Newcastle Group and the introduction of the non-marine fauna.

The stratigraphy, palaeontology and depositional environments of three ostracod-mussel bands in the Lower and Middle Coal Measures of Northumberland and Durham are described. The fossils of the Brockwell Ostracod Band, of the Carbonicola communis Zone, make up three faunal phases preserved in shale and mudstone. The Hopkins Band, in the lower Anthraconaia modiolaris Zone, is persistent over a wide area of the coalfield and shows six distinct faunal phases within the band (Pollard, 1966). The Claxheugh Shell Bed of the Upper Anthracosia similis-Anthraconaia pulchra Zone has a rich arthropod fauna preserved with non-marine mussels in an ironstone matrix.