Macaronichnus and contourite depositional settings: Bottom currents and nutrients as coupling factors

Palaeogeography Palaeoclimatology Palaeoecology, Journal Year: 2020, Volume and Issue: 545, P. 109639 - 109639

Published: Feb. 7, 2020

Language: Английский

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High‐frequency cycles of brachiopod shell beds on subaqueous delta‐scale clinoforms (early Pliocene, south‐east Spain)

Sedimentology, Journal Year: 2018, Volume and Issue: 66(5), P. 1486 - 1530

Published: Sept. 26, 2018

Abstract During the early Pliocene, subaqueous delta‐scale clinoforms developed in Águilas Basin, a mixed temperate carbonate–siliciclastic system. The facies distribution is consistent with infralittoral prograding wedge model. Stacking patterns and bounding surfaces indicate that formed during highstand falling sea‐level stages of high rank cycle. Twenty‐two clinothems were recognized over distance ≥1 km. Biostratigraphic data time span shorter than 700 kyr for whole unit ( MP l3 biozone Mediterranean Pliocene). Cyclic skeletal concentrations occasional biostromes suspension feeders (terebratulid brachiopods, modiolid bivalves adeoniform bryozoan colonies), slightly evolved glauconite Glossifungites ichnofacies on high‐frequency pulses relative rise. such stages, increased accommodation space topsets caused strong reduction terrigenous input into foresets bottomsets. This provided favourable conditions development these feeder palaeocommunities. stillstand however, reduced eventually resumed progradation foresets. There, abundance Ditrupa tubes indicates frequent siltation events extirpated terebratulid populations other epifaunal foreset bottomset subenvironments. occurrence shell beds suggests this case study represents lower rates standard examples where bound clinobedded units at their base top only. Importantly, distributions biofacies ichnoassemblage associations contribute significantly to understanding effects fluctuations evolution clinoform systems.

Language: Английский

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Mid-Cretaceous biostratigraphy (ammonites, inoceramid bivalves and foraminifers) at the eastern margin of the Anarak Metamorphic Complex (Central Iran)

Cretaceous Research, Journal Year: 2020, Volume and Issue: 110, P. 104411 - 104411

Published: March 6, 2020

Language: Английский

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Evolution of a fluvial-dominated delta during the Oligocene of the Colombian Caribbean: Sedimentological and ichnological signatures in well-cores

Journal of South American Earth Sciences, Journal Year: 2021, Volume and Issue: 111, P. 103440 - 103440

Published: June 26, 2021

Basin analysis from Colombian Caribbean is particularly important given the interest in finding hydrocarbon reservoirs, but their complex geological evolution, and frequent lateral vertical variation of facies difficult a conclusive characterization, highlights need for detailed sedimentological ichnological studies. The study succession corresponds to an interval well core drilled south Sinú-San Jacinto (Colombian Caribbean), with 1069 ft (~326 m) thick Oligocene siliciclastic succession, interpreted general terms, as deposited deltaic system. integrated sedimentological/ichnological allows differentiation dominant facies, predominant lithologies such conglomerates, sandstones, mudrocks, bioclastic sediments, coal beds. assemblage low abundance moderately diverse, composed by Conichnus, Cylindrichnus, Dactyloidites, Macaronichnus, Ophiomorpha, Phycosiphon, Skolithos, Taenidium, Teichichnus, Thalassinoides, rhizoliths. complexity sedimentary system reflected its evolution throughout Oligocene. A type coarsening-upward trend was identified it repeated through studied. It presents sediments (bioclastic sandstones mudrocks) that pass into horizontal lamination massive mudrocks occasionally bioturbated interbedded lenticular bedding, occurrence Teichichnus. Above, muddy rarely planar cross-lamination, Thalassinoides are registered. Transition carbonaceous medium beds, fine-to coarse-grained sometimes Macaronichnus and/or Ophiomorpha observed. Towards top, observed This interrupted bioturbation index generated exclusive Taenidium. Massive erosive bases, asymmetrical ripples, high content organic debris recorded. reflects progradational similar those fluvial-dominated sequences. Detailed revealed even fluvial processes were system; however, local tidal wave influence Moreover, integration information characterizing different sub-environments system, prodelta bay, distal delta front, proximal distributary channels, mouth bars, lower plain, this essential areas economic interest.

Language: Английский

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Taphonomy, ichnology, and palaeoecology to distinguish event beds in varied shallow-water settings (Betic Cordillera, SE Spain)

Journal of Iberian Geology, Journal Year: 2018, Volume and Issue: 45(1), P. 47 - 61

Published: Oct. 31, 2018

Language: Английский

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Macaronichnus ‘co-occurrence’ in offshore transition settings: Discussing the role of tidal versus fluid muds influence

Geobios, Journal Year: 2023, Volume and Issue: 80, P. 73 - 82

Published: Aug. 5, 2023

Macaronichnus is a key trace fossil in palaeoceanographic, palaeoclimatic, and petroleum exploration research. Small ichnosubspecies such as segregatis segregatis, M. s. lineiformins, maeandriformis spiriformis, typically occur wave-dominated foreshore sands where large degiberti was never found. The latter shows wide environmental distribution, occurring sandy deposits of tidal channels, bar sand sandridges, tidal-flat sheets, shorefaces, bioturbated shelf, shelf storm-sheets, ridges, upper slopes. have not been observed to date due the ecological segregation tracemakers. An abundant record Tortonian (Late Miocene) mixed carbonate-siliciclastic unit from Betic Cordillera (southern Spain) has studied. Occurrence result interaction waves, storm influenced environment determining high-energy conditions associated palaeoenvironmental parameters shifting substrates, organic matter availability, oxygenated pore bottom-waters. Locally, appear small, sinuous traces infilled by light material that were originally assigned maeandriformis, very rare spiriformis. However, absence typical rim avoid conclusive assignment. coexistence both small (?M. maeandriformis) identified underlying mudstone layers, revealing importance mud deposition during slack water intervals or linked fluid events favouring co-occurrence makers ichnosubespecies. This fact would significant palaeobiological palaeoecological implications, could be first same intervals.

Language: Английский

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Linking Western Tethyan Rhynchonellide morphogroups to the key post-Palaeozoic extinction and turnover events

Palaeogeography Palaeoclimatology Palaeoecology, Journal Year: 2020, Volume and Issue: 553, P. 109791 - 109791

Published: May 8, 2020

Language: Английский

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The environmental factors limiting the distribution of shallow-water terebratulid brachiopods

Paleobiology, Journal Year: 2020, Volume and Issue: 46(2), P. 193 - 217

Published: May 1, 2020

Abstract The Cenozoic genus Terebratula seems to be an exception the post-Permian trend in brachiopod retreat offshore habitats, because it was species rich and numerically abundant warm-temperate shallow-water environments Mediterranean Paratethys realms. This so despite general dominance of bivalves pervasive bioturbation predation pressure during Neogene. , however, went extinct Calabrian (Pleistocene). optimal environmental conditions for its prime are poorly known. Águilas Basin (SE Spain) is ideal study area investigate habitat shell beds this occur there cyclically early Pliocene deposits. We evaluate paleoecological boundary controlling distribution by estimating tolerances using benthic planktic foraminiferal nannoplanktic assemblages oxygen isotopes secondary layer calcite. Our results suggest that favored oligotrophic mesotrophic, well-oxygenated at water depths 60–90 m. Planktic point sea-surface temperatures between ~16°C 22°C, bottom-water 17°C 24°C. analyzed proxies indicate tolerated local variations depth, bottom temperature, oxygenation, productivity, organic enrichment. probably excluded grazing from well-lit preferentially occupied sediment-starved, current-swept upper habitats where coralline red algae were absent. Narrow temperature ranges might have been a disadvantage high-amplitude seawater fluctuations started about 1 Ma, when extinct.

Language: Английский

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PALAEONTOLOGY OF THE UPPER PLIOCENE MARINE DEPOSITS OF RIO VACCARUZZA, VILLALVERNIA (PIEDMONT, NW ITALY)

RIVISTA ITALIANA DI PALEONTOLOGIA E STRATIGRAFIA, Journal Year: 2022, Volume and Issue: 128(1)

Published: Feb. 15, 2022

Abstract. The topmost Argille Azzurre (beds 1-2) and the basal Sabbie di Asti 3-9) formations in Villalvernia area are analysed terms of palaeoecological taxonomic features; succession is 6 m thick dates back to middle Piacenzian within Globorotalia bononiensis acme. upper boundary clayey Bed 2 corresponds an unconformity reflecting Pliocene tectonic activity. study focused on fossil assemblages beds 3, 4 9. sandy 3 yields 362 mollusc taxa; their assemblage allochthonous mixes infra- circalittoral species accumulated by hyperpycnal mass-transport. same mechanism responsible for origin overlying unit (Bed 4) with numerous specimens Entobia-Gastrochaenolites ichnofacies. autochthonous 9 308 molluscs, plus three brachiopods ten fish most them refer Posidonia meadow (HP), autochthony shown taphonomic features as skeletal integrity, mixing successive generations or limitation juvenile ontogenetic stages vagile temporarily byssate which HP performs a nursery function. Three 52 molluscs here reported first time from Piedmont. In final chapter “Systematic Palaeontology” four 29 described, among there eight new gastropod species: Crepidula bellardii n. sp., Conus dellabellai villalvernensis Odetta chirlii Ondina curta elongata pseudovitrea Anisocycla subcylindrica sp.

Language: Английский

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Bichordites-dominated ichnofabrics from Spanish Pliocene calcarenites: traces of marine life in migrating dunes

Geological Quarterly, Journal Year: 2024, Volume and Issue: 68(4)

Published: Dec. 13, 2024

A series of Pliocene ichnofabrics is described from the Cuevas Formation, Almería-Níjar Basin south-eastern Spain, where a thick, cross-stratified, mixed bioclastic-siliciclastic succession exposed along laterally continuous section. It records dynamic conditions ancient subaqueous dunes during their deposition and activities organisms colonizing them. The are dominated by Bichordites, traces likely made burrowing sea urchins adapted to live in shifting sand. Ichnofabrics range those showing weak bioturbation with little else but Bichordites (representing high-energy, continuously migrating dunes) featuring high degree containing low moderately diverse ichnofauna more physically stable environments could gather food less agitated waters). Strong burrowers like producers have acted as ecosystem engineers. Piscichnus may preyed on benthic sand-dune organisms. non-uniform distribution ichnotaxa these sand dunes, alongside previous studies, suggests that bioturbating communities been similar modern seas.

Language: Английский

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