Palaeoecologic Significance of the Callovian-Oxfordian Trace Fossils of Gangeshwar Dome, Southeast of Bhuj, Mainland Kachchh, India

2017 ◽  
pp. 17-40 ◽  
Author(s):  
Nishith BHATT ◽  
Satish PATEL
Keyword(s):  
Trace Fossils ◽  
Marine Deposits ◽  
Clastic Sediments ◽  
Energy Gradient ◽  
Accurate Picture ◽  
Calm Water ◽  
Mode Of Life ◽  
Substrate Stability ◽  
Sandstone Facies ◽  
Offshore Region

The shallow marine deposits of the Late-Middle Jurassic (Callovian–Oxfordian) Jumara Formation of the Gangeshwar Dome of Mainland Kachchh, India, comprise a succession of ~247 m thick clastic sediments with few non-clastic bands and contain a diverse group of ichnofauna. The succession is subdivided into seven lithofacies, viz., laminated shale-siltstone facies (LSS), sheet sandstone facies (SS), herringbone sandstone facies (HS), bivalve sandstone facies (BS), bioclastic limestone facies (BL), intraformational conglomerate facies (IC) and oolitic limestone facies (OL). The ichnofaunal study shows 29 ichnospecies of 23 ichnogenera including Arenicolites, Bifungites, Bolonia, Chondrites, Didymaulichnus, Diplocraterion, Gyrochorte, Helminthopsis, Isopodichnus, Laevicyclus, Lockeia, Monocraterion, Taenidium, Ophiomorpha, Palaeophycus, Planolites, Phycodes, Protopalaeodictyon, Rhizocorallium, Skolithos, Thalassinoides, Tisoa, and Zoophycos. These trace fossils are distributed among nine ichnocoenose, characterized by Chondrites, Diplocraterion, Gyrochorte, Ophiomorpha, Rhizocorallium, Skolithos, Taenidium, Thalassinoides and Zoophycos. Their occurrence in the facies corresponds to their trophic and ethological properties. The colonisation of the opportunistic Diplocraterion and the Skolithos ichnocoenose shows a high density and marks foreshore/nearshore environmental conditions. The Gyrochorte, the Rhizocorallium, the Taenidium and the Thalassinoides ichnocoenose indicate the typically lower energy zone of the shoreface-offshore region. The Chondrites ichnocoenosis indicates fluctuation in bottom water oxygen while the Zoophycos ichnocoenosis typically exploited a calm water niche in the offshore region. These ichnocoenose recur throughout the sequence and belong to the Skolithos and the Cruziana ichnofacies which marked changes in energy gradient, substrate stability, water depth and mode of life of invertebrate organisms. The study of trace fossil assemblages with sediment characteristics gives a detailed and accurate picture of foreshore to offshore palaeoenvironmental conditions.

scholarly journals Sedimentology and ichnology of the mid-Cretaceous succession of Ouled Nail Mounts (Eastern Saharan Atlas, Algeria)

2021 ◽  
Vol 74 (3) ◽  
pp. 209-223
Author(s):  
Mohammed Nadir Naimi ◽  
◽  
Amine Cherif ◽  
Keyword(s):  
Trace Fossils ◽  
Decapod Crustaceans ◽  
Shallow Marine ◽  
Marine Deposits ◽  
Northern Algeria ◽  
Continental Intercalaire ◽  
Lowermost Part ◽  
Maximum Flooding Surface ◽  
Glossifungites Ichnofacies

Shallow marine deposits characterize the upper Albian – lower Cenomanian deposits of Northern Algeria. In Djebel Azzeddine (Ouled Nail Mounts), the corresponding sediments have been subdivided into three distinctive units A to C. The first discovered ammonite fauna from the Bou Saada area allowed the attribution of a part of the mid-Cretaceous post-Continental Intercalaire deposits to the upper Albian. The ammonite-bearing level indicates a maximum flooding surface and could be correlated with similar levels from Northern Algeria. The studied succession is characterized by a low ichnodiversity containing eight ichnotaxa with abundant Thalassinoides, common Skolithos, and rare Gyrolithes, Oichnus, Planolites and cf. Tisoa. This ichnoassemblage is dominated by domichnion, fodinichnion and praedichnion trace fossils, and is attributed to the Skolithos and Glossifungites ichnofacies. These traces are produced mainly by decapod crustaceans, polychaetes and naticid gastropods. The sedimentological and ichnological data suggest shoreface to backshore environments with mixed tide/storm energy, and long subaerial exposures indicated by Lofer cyclothems in the lowermost part and dinosaur footprints in the upper part of the section.

The Precambrian–Cambrian boundary in parts of Scandinavia and Greenland

1978 ◽  
Vol 115 (2) ◽  
pp. 131-136 ◽  
Author(s):  
Valdemar Poulsen
Keyword(s):  
Regional Distribution ◽  
Trace Fossils ◽  
Crystalline Basement ◽  
Clastic Sediments

SummaryThe discovery of Ediacara type faunas and later the Tommotian fauna at levels below the supposed first appearance of trilobites has brought new life to the discussion of the formal position of the Precambrian–Cambrian boundary. The oldest shelly faunas are apparently restricted to a few favoured areas, whereas transition beds developed as quartz sandstones, mostly unfossiliferous apart from trace fossils, seem to have a much larger regional distribution. The sequences of quartz sandstones overlie a Precambrian crystalline basement of a much greater age or clastic sediments, in part tillites, and are in turn overlain by a variety of rocks containing olenellacean trilobites.The lowering to the Cambrian boundary makes the correlation of the widespread marine sandstones below levesl with trilobites highly pertinent. The correlation of some such sandstones in Greenland and Scandinivia is discussed below. In this account the Tommotial Stage is regarded as the basal Cambrian stage.

Trace fossils from marginal marine facies of the Kanawha Formation (Middle Pennsylvanian), West Virginia

1989 ◽  
Vol 63 (4) ◽  
pp. 389-403 ◽  
Author(s):  
Ronald L. Martino
Keyword(s):  
West Virginia ◽  
Tidal Flat ◽  
Sedimentary Facies ◽  
Trace Fossils ◽  
Tidal Flats ◽  
Depositional Environments ◽  
Carbonaceous Shale ◽  
Biogenic Structures ◽  
Mouth Bars ◽  
Sandstone Facies

Seven sedimentary facies have been identified in a 40-m-thick portion of the Kanawha Formation near Chelyan in southern West Virginia. Lithology, sedimentary and biogenic structures, body fossils, paleocurrent patterns, and facies geometry have been used to identify the following paleoenvironments: Facies 1, fluviodeltaic channels represented by thick, cross-stratified channel sandstone; Facies 2, crevasse splays and tidal creeks represented by thin, cross-stratified wedge and channel sandstone; Facies 3, coastal swamps and lakes represented by coal seat and carbonaceous shale; Facies 4, restricted bay and upper tidal flats represented by dark-gray shale, mudstone; Facies 5, interdistributary bays represented by olive-gray siltstone and shale with brachiopods; Facies 6, bay or tidal flat scour fills represented by sandy limestone with brachiopods and pelmatozoans; and Facies 7, low to mid tidal flats and distributary mouth bars represented by thinly interbedded, rippled sandstone and siltstone.Trace fossils representing 17 ichnogenera are present with most being restricted to certain sedimentary facies. Three ichnoassemblages are recognized. 1) An annulated vertical burrow assemblage, consisting of arthropod(?) dwellings, occurs in an abandoned fluvial channel facies. 2) A Phycodes–Zoophycos assemblage is associated with dark-gray shales and mudstones of a restricted bay and/or upper tidal flat environment. Additional ichnogenera include Planolites and ?Conostichus. 3) An Olivellites assemblage with a high abundance and a high diversity of trace fossils occurs within a rippled sandstone/siltstone facies; trace fossils include (in order of abundance) Olivellites, Teichichnus, Planolites, Aulichnites, transversely ridged surface trails, Rosselia, Scolicia, Curvolithus, Helminthopsis, Tasmanadia, Petalichnus, Ancorichnus, and ?Asterosoma. The associated depositional environments are interpreted as low to mid tidal flats and possibly distributary mouth bars.The occurrence of salinity-sensitive trace fossils such as the assemblages described herein within otherwise faunally barren intervals facilitates the recognition of marine-influenced coastal facies in which stenohaline or brackish body fossils are lacking.

scholarly journals Darriwilian shallow-marine deposits from the Sultanate of Oman, a poorly known portion of the Arabian margin of Gondwana

2016 ◽  
Vol 155 (1) ◽  
pp. 59-84 ◽  
Author(s):  
A. P. HEWARD ◽  
G. A. BOOTH ◽  
R. A. FORTEY ◽  
C. G. MILLER ◽  
I. J. SANSOM
Keyword(s):  
Ice Sheets ◽  
Trace Fossils ◽  
Sultanate Of Oman ◽  
Polar Ice ◽  
Sea Levels ◽  
Shallow Marine ◽  
Middle Ordovician ◽  
Marine Deposits ◽  
Polar Ice Sheets ◽  
Made In

AbstractThe Amdeh Formation is a 3.4 km stack of sparsely fossiliferous quartzites and shales which crops out in the Al Hajar mountains near Muscat. Here we describe the uppermost member (Am5) that can be dated biostratigraphically as Darriwilian and which is the outcrop equivalent, and probably the seaward continuation, of the Saih Nihayda Formation in the Ghaba Salt Basin of northern Oman. The outcrops at Wadi Daiqa and Hayl al Quwasim consist of 690 m of quartzitic sandstones, shales and bivalve-rich shell beds. Trace fossils referable to the Cruziana and Skolithos ichnofacies abound. The member comprises storm-dominated shelf, shoreface and delta deposits. A number of new discoveries have been made in the outcrops: fragments of the arandaspid fish Sacabambaspis, ossicles and moulds of the early disparid crinoid Iocrinus, two new genera of conodont, an occurrence of the rare trinucleid trilobite Yinpanolithus, and palynological and sedimentological evidence of more continuous Floian–Darriwilian deposition than is usual in the region. Sea levels during Middle Ordovician time are estimated to have been 50–200 m above present levels and a wide, low-gradient shelf covered much of Arabia. Similar trace fossils and storm-dominated, micro-tidal, sedimentary rocks occur throughout the region. Small changes of sea level, possibly caused by the growth and melting of polar ice sheets, could lead to substantial seaward or landward shifts of facies belts. The Am5 deposits are thick compared to most equivalents in Arabia implying active subsidence and a ready supply of sediment.

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.

scholarly journals Glauconitic deposits at Julegård on the south coast of Bornholm, Denmark dated to the Cambrian

2011 ◽  
Vol 59 ◽  
pp. 1-12
Author(s):  
Lars B. Clemmensen ◽  
Richard G. Bromley ◽  
Paul Martin Holm
Keyword(s):  
Lower Cambrian ◽  
Trace Fossils ◽  
Upper Triassic ◽  
South Coast ◽  
The South ◽  
Shallow Marine ◽  
Marine Deposits

Bioturbated, glauconitic siltstones and sandstones are overlain by presumed Upper Triassic deposits at coastal exposures at Julegård on the south coast of Bornholm. These glauconitic deposits have not previously been dated. A 40Ar-39Ar dating of the glaucony gives an age of 493 ± 2 Ma suggesting the deposits belong to the Lower Cambrian Norretorp Member of the Læså Formation. The shallow marine deposits are strongly bioturbated, but only a single ichnoassociation is represented. The ichnogenus is referable to either Trichophycus Miller and Dyer, 1878 or Teichichnus Seilacher, 1955. Rare examples of Rusophycus Hall, 1852, probably trilobite trace fossils, are also represented.

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.

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