Trace fossils and ichnofabric in the Kj0lby Gaard Marl, uppermost Cretaceous, Denmark

The Kj0lby Gaard Marl (Late Maastrichtian) is a 30 cm-thick, grayish brown, clay-rich, pelagic carbonate unit (75 to 85% CaCO3 ) exposed in the Limfjord region of northern Jylland, Denmark. Trace fossil suites and ichnofabric (the sedimentary fabric resulting from all phases of bioturbation) reflect a complex depositional and post-depositional history of the marl unit, which is sandwiched between comparatively pure chalk strata above and below. Initiation of marl deposition occurred gradually and episodically, as indicated by a micro-styolitic fabric resulting from solution-compaction of finely alternating chalk and clay laminae in the basal portion of the bed. During the major phase of marl deposition represented by the middle and upper parts of the unit, the sea floor apparently was very soft and was colonized by an active infauna which produced a low-diversity suite of trace fossils dominated by horizontal burrows. These are now preserved in a highly compacted ichnofabric which is totally bioturbated but contains no easily identifiable trace fossils. As the sedimentary mode returned to chalk deposition, the marl was buried and subsequently strengthened by compaction sufficiently to allow its colonization by a deeper-burrowing infauna that normally preferred somewhat stiffer, chalky substrates. Thus, the original ichnofat,ric was modified by the introduction of late-generation, sharply defined and relatively uncompacted "chalk" trace fossils (Thalassinoides, Zoophycos and Chondrites, probably appearing in that order). These are superimposed directly on top of the earlier, highly deformed burrows of the initial trace fossil suite.

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Coniacian sandstones from the North Sudetic Synclinorium revisited: palaeoenvironmental and palaeogeographical reconstructions based on trace fossil analysis and associated body fossils

Geologos ◽

10.2478/logos-2018-0003 ◽

2018 ◽

Vol 24 (1) ◽

pp. 29-53 ◽

Cited By ~ 1

Author(s):

Alina Chrząstek ◽

Monika Wypych

Keyword(s):

Trace Fossils ◽

Trace Fossil ◽

Fair Weather ◽

Soft Substrate ◽

Southeastern Part ◽

Shallow Marine ◽

The North ◽

Low Diversity ◽

Storm Deposits ◽

Interesting Compound

AbstractThe Coniacian quartz sandstones (Żerkowice Member, Rakowice Wielkie Formation) that crop out at quarries near Czaple-Nowa Wieś Grodziska (North Sudetic Synclinorium) contain a low-diversity assemblage of trace fossils:Gyrochorteisp.,Ophiomorpha nodosaLundgren, 1891,Ophiomorphaisp.,Phycodescf.curvipalmatum(Pollard, 1981), ?Phycodesisp.,Planolitescf.beverleyensis(Billings, 1862),Thalassinoides paradoxicusWoodward, 1830 and ?Thalassinoidesisp. Moreover, interesting compound burrow systems, here referred to asThalassinoides-Phycodescf.palmatusand ?Thalassinoides-Phycodes, were recognised at the Czaple Quarry. Additionally, ?Gyrochorteisp.,Phycodescf.flabellum(Miller and Dyer, 1878) and ?Treptichnusisp. were encountered at correlative levels in the Rakowice Małe Quarry. Some of these ichnotaxa have not been recorded previously from Coniacian sandstones of the Żerkowice Member. Additionally, in slabs of these sandstones, the gastropodNerinea bicinctaBronn, 1836 and the bivalveLima haidingeriZittel, 1866 were found. These interesting finds, in particular the gastropods, were already noted from the study area in the first half of the twentieth century by Scupin (1912–1913). Ethologically, the trace fossil assemblage is represented by domichnia or domichnia/fodinichnia (Ophiomorpha,Thalassinoides), fodinichnia (Phycodes) and pascichnia (Gyrochorte,Planolites). The compound burrow systems (Thalassinoides-Phycodes) are interpreted as dwelling/feeding structures. The possible tracemakers are crustaceans (Ophiomorpha,Thalassinoides) or worm-like animals (annelids and other) (Planolites, ?Phycodes,Gyrochorteand ?Treptichnus). The assemblage of trace fossils is characteristic of theSkolithosichnofacies andCruzianaichnofacies, typical of shallow-marine settings. Ichnological studies, as well as the presence of accompanying fossils (bivalves, gastropods), confirm the palaeoenvironmental reconstruction of the Żerkowice Member sandstones by Leszczyński (2010). That author interpreted the Coniacian sandstones as bar and storm deposits laid down in a shallow epicontinental sea (mainly the foreshore-upper shoreface; up to the middle shoreface) under normal oxygenation and salinity, in soft substrate, above fair-weather wave base. The deposition of the Żerkowice Member sandstones is linked to a regression that started after uplift of the southeastern part of the North Sudetic Synclinorium.

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Trace fossil assemblages reflecting stressed environments in the Middle Jurassic Carmel Seaway of central Utah

Journal of Paleontology ◽

10.1017/s0022336000032522 ◽

1999 ◽

Vol 73 (4) ◽

pp. 711-720 ◽

Cited By ~ 31

Author(s):

J. M. De Gibert ◽

A. A. Ekdale

Keyword(s):

Benthic Community ◽

Middle Jurassic ◽

Trace Fossils ◽

Trace Fossil ◽

Pore Waters ◽

Shallow Marine ◽

Marine Carbonate ◽

Marine Carbonates ◽

Low Diversity ◽

Fossil Assemblages

The shallow-marine Carmel Formation (Middle Jurassic) in central Utah hosts low-diversity trace fossil assemblages, including Arenicolites, Chondrites, Gyrochorte, Lockeia, Planolites, Protovirgularia, Rosselia, Scalarituba, Skolithos, Taenidium, and Teichichnus. Non specialized ichnotaxa with a remarkably small burrow size dominate the assemblages. The amount of bioturbation is lower than expected in comparison with modern shallow-marine carbonate environments. These ichnological features also are significantly different from those of other Jurassic shallow-marine carbonates. The trace fossils represent an environmentally stressed benthic community in a marginal marine, restricted setting, with salinities above normal marine and with depletion of oxygen in pore waters.

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

Journal of Paleontology ◽

10.1017/s0022336000028626 ◽

1987 ◽

Vol 61 (3) ◽

pp. 439-450 ◽

Cited By ~ 8

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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Depositional history of Middle-Upper Jurassic succession at the Binalud mountains, NE Iran: implications of ammonite, trace fossil and stable isotopes in palaeoenvironmental analysis

Historical Biology ◽

10.1080/08912963.2018.1563078 ◽

2019 ◽

Vol 32 (8) ◽

pp. 1036-1053

Author(s):

Ahmad Raoufian ◽

Hamed Zand-Moghadam ◽

Kazem Seyed-Emami

Keyword(s):

Stable Isotopes ◽

Upper Jurassic ◽

Trace Fossil ◽

Depositional History ◽

History Of ◽

Ne Iran

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Lithostratigraphy of the Kweekvlei Formation (Witteberg Group), Cape Supergroup

South African Journal of Geology ◽

10.25131/gssajg.120.3.421 ◽

2017 ◽

Vol 120 (3) ◽

pp. 421-432 ◽

Cited By ~ 2

Author(s):

C. Browning ◽

M. Reid

Keyword(s):

South Africa ◽

Transition Zone ◽

Distal Part ◽

Vascular Plant ◽

Trace Fossil ◽

Plant Debris ◽

Lower Carboniferous ◽

Fossil Assemblage ◽

Low Diversity ◽

Storm Wave

AbstractThe Lower Carboniferous, probably Tournaisian, Kweekvlei Formation is part of the Witteberg Group (Cape Supergroup) of South Africa. Together with the overlying Floriskraal Formation, it forms an upward-coarsening succession within the Lake Mentz Subgroup. Sedimentary features of the Kweekvlei Formation suggest deposition in a storm-wave dominated marine setting, within the storm-influenced, distal part of an offshore transition zone environment. This predominantly argillaceous formation preserves a low diversity trace fossil assemblage. Reworked vascular plant debris (including the problematic genus Praeramunculus sp.) and a shark spine have been reported for the Kweekvlei Formation. There are no known stratigraphic equivalents in South Africa.

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