Devonian depositional environments in the Darwin Mountains: Marine or non-marine?

1993 ◽  
Vol 5 (2) ◽  
pp. 211-220 ◽  
Author(s):  
Ken J. Woolfe
Keyword(s):  
Fresh Water ◽  
Depositional Environment ◽  
Trace Fossils ◽  
Depositional Environments ◽  
Trace Fossil ◽  
Glacier Area ◽  
Red Beds ◽  
Fossil Assemblage ◽  
Considerable Debate

The depositional environment of the Devonian Taylor Group has been subject to considerable debate for over 30 years. The debate stems largely from a belief that the abundant and diverse trace fossils represent a marine ichnofauna, whereas sedimentary features, including palaeosols, desiccation polygons and red beds, are more typical of a non-marine setting. The debate is reconciled by a reinterpretation of the trace fossil assemblage which shows that the trace fossils comprise a typical fresh water (Scoyenia ichnofacies) assemblage, and their occurrence in the Taylor Group in the Darwin Glacier area is entirely consistent with deposition in a mixed fluvial-lacustrine-subaerial environment.

scholarly journals CHONDRITES-CLADICHNUS ICHNOCOENOSIS FROM THE DEEP-SEA DEPOSITS OF PIERFRANCESCO (CRETACEOUS; ITALY): OXYGEN- OR NUTRIENT-LIMITED?

2022 ◽  
Vol 128 (1) ◽  
Author(s):  
ANDREA BAUCON ◽  
GIROLAMO LO RUSSO ◽  
CARLOS NETO DE CARVALHO ◽  
FABRIZIO FELLETTI
Keyword(s):  
Late Cretaceous ◽  
Deep Sea ◽  
Trace Fossils ◽  
Northern Apennines ◽  
Trace Fossil ◽  
Ecological Succession ◽  
Rhythmic Pattern ◽  
Low Oxygen ◽  
Fossil Assemblage

The Italian Northern Apennines are acknowledged as the place where ichnology was born, but there is comparatively little work about their ichnological record. This study bridges this gap by describing two new ichnosites from the locality of Pierfrancesco, which preserve an abundant, low-disparity trace-fossil assemblage within the Late Cretaceous beds of the M. Cassio Flysch. Results show that lithofacies and ichnotaxa are rhythmically organized. The base of each cycle consists of Megagrapton-bearing calciclastic turbidites, which are overlain by marlstone beds with an abundant, low-disparity assemblage of trace fossils. This includes Chondrites intricatus, C. patulus, C. targionii, C. recurvus and Cladichnus fischeri. The cycle top consists of mudstones with no distinct burrows. The rhythmic pattern of Pierfrancesco reflects a deep-sea ecological succession, in which species and behaviour changed as turbidite-related disturbances altered the seafloor. This study opens the question of whether the Chondrites-Cladichnus ichnocoenosis represents low-oxygen or nutrient-poor settings.

The Fish River Subgroup in Namibia: stratigraphy, depositional environments and the Proterozoic–Cambrian boundary problem revisited

2005 ◽  
Vol 142 (5) ◽  
pp. 465-498 ◽  
Author(s):  
G. GEYER
Keyword(s):  
Trace Fossils ◽  
Global Scale ◽  
Depositional Environments ◽  
Trace Fossil ◽  
Braided River ◽  
Shallow Marine ◽  
Sequence Stratigraphic ◽  
Marine Habitats ◽  
Short Period ◽  
Distinct Sequence

The Fish River Subgroup of the Nama Group, southern Namibia, is restudied in terms of lithostratigraphy and depositional environment. The study is based on partly fine-scaled sections, particularly of the Nababis and Gross Aub Formation. The results are generally in accordance with earlier studies. However, braided river deposits appear to be less widely distributed in the studied area, and a considerable part of the formations of the middle and upper subgroup apparently were deposited under shallowest marine conditions including upper shore-face. Evidence comes partly from sedimentary features and facies distribution, and partly from trace fossils, particularly Skolithos and the characteristic Trichophycus pedum. Environmental conditions represented by layers with T. pedum suggest that the producer favoured shallow marine habitats and transgressive regimes. The successions represent two deepening-upward sequences, both starting as fluvial (braided river) systems and ending as shallow marine tidally dominated environments. The first sequence includes the traditional Stockdale, Breckhorn and lower Nababis formations (Zamnarib Member). The second sequence includes the upper Nababis (Haribes Member) and Gross Aub formations. As a result, the Nababis and Gross Aub formations require emendation: a new formation including the Haribes and Rosenhof and possibly also the Deurstamp members. In addition, four distinct sequence stratigraphic units are deter-minable for the Fish River Subgroup in the southern part of the basin. The Proterozoic–Cambrian transition in southern Namibia is most probably located as low as the middle Schwarzrand Subgroup. The environmentally controlled occurrence of Trichophycus pedum undermines the local stratigraphic significance of this trace fossil which is eponymous with the lowest Cambrian and Phanerozoic trace fossil assemblage on a global scale. However, occurrences of such trace fossils have to be regarded as positive evidence for Phanerozoic age regardless of co-occurring body fossils. Other suggestions strongly dispute the concept of the formal Proterozoic–Cambrian and Precambrian–Phanerozoic boundary. Carbon isotope excursions and radiometric datings for the Nama Group do not help to calibrate precisely the temporal extent of the Fish River Subgroup. Fossil content, sequence stratigraphy and inferred depositional developments suggest that this subgroup represents only a short period of late orogenic molasse sedimentation during the early sub-trilobitic Early Cambrian.

The evolutionary significance of a Lower Cambrian trace-fossil assemblage from the Meguma terrane, Nova Scotia

2011 ◽  
Vol 48 (1) ◽  
pp. 71-85 ◽  
Author(s):  
Murray K. Gingras ◽  
John W.F. Waldron ◽  
Chris E. White ◽  
Sandra M. Barr
Keyword(s):  
Nova Scotia ◽  
Lower Cambrian ◽  
Trace Fossils ◽  
Trace Fossil ◽  
Evolutionary Significance ◽  
Fossil Assemblage ◽  
Approximate Order ◽  
Meguma Terrane ◽  
Wrinkle Structures ◽  
Fossil Preservation

We report a diverse assemblage of trace fossils from the Lower(?) Cambrian High Head member of the Church Point Formation near Yarmouth, Nova Scotia. Based on the presence of sharp-based beds, load casts, and flute casts, along with other sedimentological criteria, the strata are interpreted to have a turbidite origin. Other characteristics, including wrinkle structures and high fidelity of trace-fossil preservation, suggest that the inter-episode biotope was influenced by the presence of biomats. The trace-fossil assemblage includes (in approximate order of abundance) Planolites , Helminthopsis , Oldhamia , Chondrites , Gordia , Cladichnus , Psammichnites gigas , Treptichnus , Phycodes , Lorenzinia , Palaeophycus , and Teichichnus . Trace fossils are increasingly abundant upwards in the section, but they are ultimately mitigated by an increase in (inferred) sedimentation rates. The trace-fossil assemblage, which bears many similarities to other Lower Cambrian locales (e.g., Puncoviscana Formation of northwest Argentina, Chapel Island Formation of southeastern Newfoundland), and the distribution of ichnofossils strongly support an earliest Cambrian age for the studied strata. More importantly, evolutionary trends can be interpreted from the trace-fossil assemblage, namely (1) an increase in size and diversity of animals in deep water; (2) an expansion of motile strategies used to coexist with biomats; and, (3) increasingly complex mining strategies below the sediment-biomat interface.

scholarly journals Sedimentology and Ichnology of Paleozoic Estuarine and Shoreface Reservoirs, Morrow Sandstone, Lower Pennsylvanian of Southwest Kansas, USA

1999 ◽  
pp. 1-35
Author(s):  
Luis A. Buatois ◽  
Gabriela M. Mangano ◽  
Timothy R. Carr
Keyword(s):  
Oil And Gas ◽  
Petroleum Industry ◽  
Integrated Approach ◽  
Trace Fossils ◽  
Depositional Environments ◽  
Trace Fossil ◽  
Reservoir Modeling ◽  
Delta Front ◽  
Valley Fill ◽  
Biogenic Structures

Integration of facies and trace-fossil evidence tests and refines depositional models constructed solely on the basis of physical sedimentology. In recent years, the petroleum industry has increasingly used trace-fossil analysis of cores as an aid in reservoir characterization. In particular, ichnologic data have been instrumental in the recognition of estuarine deposits and their distinction from open-marine facies (e.g., MacEachern and Pemberton, 1994). Previous ichnologic analyses of cores, however, have concentrated on post-Paleozoic reservoirs (e.g., Bockelie, 1991; Pemberton, 1992; Taylor and Gawthorpe, 1993; Howell et al., 1996; Martin and Pollard, 1996; MacEachern and Pemberton, 1997). The present study represents one of the first attempts to apply trace-fossil analysis to cores from Paleozoic reservoirs. The Lower Pennsylvanian Morrow Sandstone contains oil and gas reservoirs in a wide variety of shallow and marginal-marine depositional environments. Delta-front, shoreface, and estuarine valley-fill reservoir sandstones are encased in offshore and estuarine mudstones (Sonnenberg, 1985; Krystinik and Blakeney, 1990; Sonnenberg et al., 1990; Wheeler et al., 1990). An integrated stratigraphic, sedimentologic, and ichnologic study provides a more accurate characterization of reservoir facies and geometry. This study allows distinction between marine-shoreface and estuarine valley-fill sandstones from four cores of the lower Morrow in southwestern Kansas. Core analysis subsequently was integrated with well-log information. Previous studies have emphasized the presence of estuarine valley-fills in the upper Morrow (Wheeler et al., 1990). Our integrated approach extends the estuarine valley interpretation into the lower Morrow. Within the midcontinent, trace fossils are useful in distinguishing different facies in estuarine incised valleys and marine shorefaces. Detailed study of biogenic structures provides high-resolution information to solve problems in facies, stratigraphic, and reservoir modeling. In some cases, they represent the only evidence available to develop a reasonable picture of depositional conditions and to estimate reservoir heterogeneity. The present study provides a detailed analysis of the sedimentary facies, documents the associated trace fossils, and illustrates how trace fossils are used to refine environmental interpretations of the lower Morrow sandstone reservoirs.

scholarly journals Notes on Greenland trace fossils

1972 ◽  
Vol 49 ◽  
pp. 1-30
Author(s):  
R.G Bromley ◽  
U Asgaard
Keyword(s):  
Trace Fossils ◽  
Lower Jurassic ◽  
Upper Triassic ◽  
Trace Fossil ◽  
Morphological Description ◽  
Field Observations ◽  
Burrow System ◽  
Red Beds ◽  
Present Material ◽  
East Greenland

Freshwater Cruziana from the Upper Triassic of Jameson Land, East Greenland.An occurrence of well-preserved Cruziana problematica (Schindewolf) in Triassic red-beds in Jameson Land allows a more detailed morphological description of these trace fossils than has hitherto been possible. Rheotactic orientation of the traces indicates the direction of palaeocurrents in the area. C. problematica has previously been ascribed to branchiopod crustaceans, but the present material allows a narrowing of the field to Notostraca, and is supported by field observations of the living notostracan Lepidurus arcticus (Pallas).The burrows and microcoprolites of Glyphea rosenkrantzi, a Lower Jurassic palinuran crustacean from Jameson Land, East Greenland.In Toarcian sediments in Jameson Land, phosphatic concretions at certain horizons contain well preserved Glyphea rosenkrantzi. These crustaceans are confined to the fill of Thalassinoides burrow systems and it is therefore probable that the burrows were constructed by Glyphea. It is possibIe that associated microcoprolites of rod-like shape, without internal canals, may also be ascribed to the Glyphea.A large radiating burrow-system in Jurassic micaceous sandstones of Jameson Land, East Greenland. Large trace fossils consisting of more or less straight burrows radiating from a verticaI shaft are described from Jurassic sandstones of Jameson Land. The mica orientation of the sediment reveals the internal construction of the burrows and aids the interpretation of their mode of formation. The trace fossil has not been previously named and is designated Phoebichnus trochoides ichnogen. et ichnosp. nov.

scholarly journals Asteriacites and other trace fossils from the Po Formation (Visean–Serpukhovian), Ganmachidam Hill, Spiti Valley (Himalaya) and its paleoenvironmental significance

2017 ◽  
Vol 68 (5) ◽  
pp. 464-478 ◽  
Author(s):  
Birendra P. Singh ◽  
Om N. Bhargava ◽  
Radek Mikuláš ◽  
Subhay K. Prasad ◽  
Garry Singla ◽  
...  
Keyword(s):  
Trace Fossils ◽  
Trace Fossil ◽  
Fossil Assemblage ◽  
Sedimentary Structures ◽  
The Village ◽  
The Himalaya ◽  
Open Shelf

Abstract An assemblage of trace fossils comprising Asteriacites stelliformis, A. quinquefolius, Biformites insolitus, Helminthoidichnites? isp., Lingulichnus isp., Lockeia siliquaria, Palaeophycus tubularis, Planolites isp., Protovirgularia isp. A, Protovirgularia isp. B, Protovirgularia isp. C, Psammichnites isp., Rusophycus isp., and Treptichnus isp. from the Po Formation (Visean-Serpukhovian) exposed along the base of Ganmachidam Hill near the village of Chichong, Spiti Valley in the Himalaya, is described. Storm beds (tempestites) are highly bioturbated. Sedimentary structures such as hummocky cross-stratification (HCS), low-angle planar and trough cross beds, and shallow, slightly asymmetrical gutter casts are observed. The overall trace fossil assemblage indicates the presence of upper shoreface to lower shoreface Cruziana ichnofacies of an open shelf.

scholarly journals Ichnological analysis at the Fonte Coberta section (Lusitanian Basin, Portugal): Approaching depositional environment during the Toarcian oceanic anoxic event (T-OAE)

2018 ◽  
Vol 33 (2) ◽  
pp. 261 ◽  
Author(s):  
Olmos Miguez-Salas ◽  
Francisco J. Rodríguez-Tovar ◽  
Luis V. Duarte
Keyword(s):  
Depositional Environment ◽  
Environmental Parameters ◽  
Single Species ◽  
Trace Fossil ◽  
Anoxic Conditions ◽  
Oceanic Anoxic Event ◽  
Fossil Assemblage ◽  
Anoxic Event ◽  
High Degree ◽  
Lusitanian Basin

The Toarcian Oceanic Anoxic Event (T-OAE) is commonly related with an extended marine mass extinction and global oceanic anoxic conditions. However, recently it has been demonstrated that local palaeotopography/palaeogeography can determinate the absence of anoxic conditions, being other limiting environmental parameters of higher signifi cance. The detailed study of the Fonte Coberta section (Lusitanian Basin, Portugal) shows significant changes in the macrobenthic community at the lower Toarcian (Levisoni Zone) sediments during the event. In the study section, this interval presents a high degree of bioturbation with a relatively abundant and moderately diverse trace fossil assemblage dominated by Thalassinoides, with punctual Spongeliomorpha. The ichnotaxonomical study conducted on this trace fossil assemblage has allowed the recognition of a single species of Thalassinoides, T. suevicus Rieth, with two different morphotypes (I and II), as well the differentiation of Spongeliomorpha aff . iberica Saporta. The distribution of these ichnospecies, including the differentiated morphogroups, along the studied interval, corresponding to the T-OAE, allows refining depositional conditions as changes in the substrate consistency related to variations in relative sea level. Ichnological analysis reveals as a proxy to improve sequence stratigraphy characterization for the Lusitanian Basin during the T-OAE.

scholarly journals Trace fossils from the Lower and Middle Jurassic marginal marine deposits of the Sorthat Formation, Bornholm, Denmark

2003 ◽  
Vol 50 ◽  
pp. 185-208
Author(s):  
Richard G. Bromley
Keyword(s):  
Middle Jurassic ◽  
Trace Fossils ◽  
Trace Fossil ◽  
South Coast ◽  
Marine Environments ◽  
Salinity Fluctuation ◽  
Fossil Assemblage ◽  
Marine Deposits ◽  
Low Degree ◽  
The Baltic

The Lower to Middle Jurassic Sorthat and Bagå Formations of the Baltic island of Bornholm, Denmark, are a predominantly fluviatile unit. On the south coast of the island at Korsodde, however, an interval within the Sorthat Formation contains a diverse trace fossil assemblage indicating a marine incursion. Study of this interval revealed 15 ichnotaxa, among which one is new: Bornichnus tortuosus nov. igen. et isp. Several of the trace fossils present are generally considered characteristic of the lower shoreface to offshore environments (e.g. Teichichnus and Asterosoma). However, the low degree of bioturbation and ichnodiversity, and sedimentological features, indicate an environment influenced by salinity fluctuation, probably a tidally influenced delta. Five ichnofabrics are defined that describe this setting and which may be indicative of marginal-marine environments that are influenced by salinity fluctuations.

Invertebrate paleoecology of the Upper Cliff coal interval (Pennsylvanian), Plateau Coal Field, northern Alabama

1987 ◽  
Vol 61 (3) ◽  
pp. 439-450 ◽  
Author(s):  
Michael A. Gibson ◽  
Robert A. Gastaldo
Keyword(s):  
Fresh Water ◽  
Trace Fossils ◽  
Trace Fossil ◽  
Coal Field ◽  
Storm Activity ◽  
Marine Deposits ◽  
Sand Body ◽  
Low Diversity ◽  
Abundance And Diversity ◽  
Shell Bed

The Upper Cliff coal interval (Early Pennsylvanian) of northern Alabama consists of sandstone, siltstone, shale, and coal deposited within a southwestward prograding deltaic complex as previously defined using paleobotanical and sedimentological evidence. The paleoecology of two invertebrate-bearing lithofacies was studied within this context. A lower shaley-siltstone lithofacies records the inundation of the Upper Cliff #1 peat-accumulating swamp/marsh by fresh-water influenced brackish to restricted marine deposits. The fauna is dominated by the inarticulate Orbiculoidea and the trace fossil Planolites. As inundation continued, an interdistributary bay developed. Diversity and abundance of taxa increased with the establishment of a molluscan dominated Pteronites-Pianolites assemblage. The assemblage consists of a low diversity and low abundance fauna of bivalves and trace fossils that suggest soft substrates with abundant organics.The overlying sandstone lithofacies consists of a basal shell-bed (Schizophoria zone) composed of rare indigenous Pteronites and Wilkingia and a transported component of open marine epifaunal brachiopods, gastropods, and trilobite fragments. The Schizophoria zone thins to the northeast, suggesting open marine conditions to the southwest. Directly above this bed, the fauna of the sandstone lithofacies is composed entirely of Zoophycos. Higher in the section, rare Pteronites and Wilkingia occur, thus this lithofacies preserves a Wilkingia-Pteronites-Zoophycos assemblage of low abundance and diversity reflecting mobile organic-poor substrates. The sandstone lithofacies is interpreted as a migrating sand body with a basal shell-bed, initially formed probably as a result of storm activity.

The trace fossil Yakutatia emersoni from the Cretaceous Kodiak Formation of Alaska

1986 ◽  
Vol 23 (2) ◽  
pp. 262-269 ◽  
Author(s):  
T. McCann ◽  
R. K. Pickerill
Keyword(s):  
Depositional Environment ◽  
Distal Part ◽  
Trace Fossils ◽  
Trace Fossil ◽  
Submarine Fan ◽  
Kodiak Island

The enigmatic trace fossil Yakutatia emersoni has previously only been briefly described from the Cretaceous Kodiak Formation of Kodiak Island, Alaska. Herein we examine the trace fossil in detail, confirm that it is indeed a graphoglyptid, note the associated trace fossils, interpret the depositional environment of the strata in which it occurs as most probably a lobe fringe environment in the distal part of a large submarine fan, and designate a lectotype.

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