Environmental change during the Late Famennian and Early Tournaisian (Late Devonian–Early Carboniferous): implications from stable isotopes and conodont biofacies in southern Europe

2008 ◽  
Vol 43 (2-3) ◽  
pp. 241-260 ◽  
Author(s):  
Sandra I. Kaiser ◽  
Thomas Steuber ◽  
R. Thomas Becker
2021 ◽  
pp. 1-22
Author(s):  
Jon A. Lakin ◽  
John E.A. Marshall ◽  
Ian Troth

Abstract The Devonian/Carboniferous Boundary (DCB) interval is associated with mass extinction, isotope excursions and a short glacial episode. This study investigates how boundary extinction and environmental change is expressed in the glacial high-palaeolatitudinal record of the Bolivian Altiplano (western Gondwana). A latest Devonian and early Carboniferous section has been investigated using sedimentology, palynology, total organic carbon and bulk δ13Corganic. The Colpacucho Formation is a Late Devonian shelfal–marine siliciclastic sequence. It is overlain in the study area by a unit of coarse sandstones and sandy diamictites, interpreted as glaciomarine. This distinctive glaciomarine unit is at least 7 km wide and 60–120 m thick with a variably incisive basal contact (<100 m). It is of very latest Famennian age and is a stratigraphic equivalent of proven glacigenic deposits across central South America. The offshore marine Kasa Formation overlies the glacigenic unit above a basal flooding surface. The DCB is 12 m above this flooding surface on the last occurrence of Retispora lepidophyta and significant palynological assemblage changes. This includes the loss of the Umbellasphaeridium saharicum phytoplankton bioprovince, endemic to Gondwana. Marine and terrestrial palynological extinctions are synchronous with a 2 ‰ positive carbon isotope excursion interpreted to be reflective of changes in organic matter delivery and preservation during an interval of environmental stress. These results inform wider debates on global environmental change and mass extinction at the DCB.


2001 ◽  
Vol 75 (6) ◽  
pp. 1202-1213 ◽  
Author(s):  
Robert L. Carroll

The origin of tetrapods from sarcopterygian fish in the Late Devonian is one of the best known major transitions in the history of vertebrates. Unfortunately, extensive gaps in the fossil record of the Lower Carboniferous and Triassic make it very difficult to establish the nature of relationships among Paleozoic tetrapods, or their specific affinities with modern amphibians. The major lineages of Paleozoic labyrinthodonts and lepospondyls are not adequately known until after a 20–30 m.y. gap in the Early Carboniferous fossil record, by which time they were highly divergent in anatomy, ways of life, and patterns of development. An even wider temporal and morphological gap separates modern amphibians from any plausible Permo-Carboniferous ancestors. The oldest known caecilian shows numerous synapomorphies with the lepospondyl microsaur Rhynchonkos. Adult anatomy and patterns of development in frogs and salamanders support their origin from different families of dissorophoid labyrinthodonts. The ancestry of amniotes apparently lies among very early anthracosaurs.


2019 ◽  
Vol 6 (5) ◽  
pp. 182087 ◽  
Author(s):  
Jennifer A. Clack ◽  
Marcello Ruta ◽  
Andrew R. Milner ◽  
John E. A. Marshall ◽  
Timothy R. Smithson ◽  
...  

The enigmatic tetrapod Acherontiscus caledoniae from the Pendleian stage of the Early Carboniferous shows heterodontous and durophagous teeth, representing the earliest known examples of significant adaptations in tetrapod dental morphology. Tetrapods of the Late Devonian and Early Carboniferous (Mississippian), now known in some depth, are generally conservative in their dentition and body morphologies. Their teeth are simple and uniform, being cone-like and sometimes recurved at the tip. Modifications such as keels occur for the first time in Early Carboniferous Tournaisian tetrapods. Acherontiscus , dated as from the Pendleian stage, is notable for being very small with a skull length of about 15 mm, having an elongate vertebral column and being limbless. Cladistic analysis places it close to the Early Carboniferous adelospondyls, aïstopods and colosteids and supports the hypothesis of ‘lepospondyl’ polyphyly. Heterodonty is associated with a varied diet in tetrapods, while durophagy suggests a diet that includes hard tissue such as chitin or shells. The mid-Carboniferous saw a significant increase in morphological innovation among tetrapods, with an expanded diversity of body forms, skull shapes and dentitions appearing for the first time.


1999 ◽  
Vol 36 (8) ◽  
pp. 1281-1298 ◽  
Author(s):  
Lauret E Savoy ◽  
Anita G Harris ◽  
Eric W Mountjoy

Uppermost Devonian and Lower Mississippian strata in the Rocky Mountains of southwestern Canada and northwestern Montana record widespread oceanographic changes during middle to late Paleozoic time associated with the termination of a carbonate ramp system, the onset of a deep-water, low-oxygen event and possible marginal tectonism, and the later reestablishment of a carbonate ramp. Integrated lithofacies and conodont biofacies developed previously for these strata between the Bow Valley and the international border have been extended northward to the Athabasca region of the Alberta Rocky Mountains. During early-middle Famennian time, the southern Canadian Rocky Mountains region was the site of a westward-deepening and westward-thickening carbonate ramp system (Palliser Formation). By late Famennian time carbonate ramp deposition ended and was followed by widespread deposition of organic-rich, low-oxygen facies in shelf to basinal environments (Exshaw Formation and correlative units). The overlying Banff Formation consists of anaerobic to marginally aerobic, starved-basin to deep-ramp lithofacies succeeded by shallower water carbonates; this sequence records basinward (westward) progradation of the Banff ramp in middle to late Tournaisian time. Distinct conodont biofacies representative of shallow-ramp to deep-basin settings that were previously recognized in the southernmost Canadian Rocky Mountains and Montana have also been identified to the north between the North Saskatchewan and Athabasca valleys. Upper Palliser carbonates contain low-diversity conodont faunas of indigenous to transported palmatolepid-, polygnathid-, and apatognathid-dominated assemblages. Exshaw deposits contain indigenous and reworked palmatolepid- and bispathodid-dominated assemblages and reworked or transported polygnathids. Lower Banff biofacies include transported and indigenous assemblages of siphonodellids, polygnathids, and pseudopolygnathids representative of the deep-middle Banff ramp. Polygnathid-hindeodid biofacies of shallower middle-ramp environments occur higher in the Banff Formation in the North Saskatchewan and Athabasca valleys.


1997 ◽  
Vol 134 (5) ◽  
pp. 691-702 ◽  
Author(s):  
A. ŻELAŹNIEWICZ

Two metasedimentary complexes are exposed in the Sudetes Mountains of Poland, Germany and the Czech Republic. Succession I comprises pelites and greywackes of Neoproterozoic–Cambrian age, deformed and metamorphosed prior to intrusion by S-type porphyritic granites at 515–480 Ma. Succession II comprises a sandstone–mudstone–chert sequence and turbidite sequence of Ordovician–early Carboniferous age accompanied by bimodal volcanogenic rocks. Both successions were intruded by late- to post-orogenic granitoid intrusions at 340–300 Ma. The sedimentary rocks of succession II show increasing maturity until mid–late Devonian times. Inversion of the basins, commencing in late Devonian–early Carboniferous times, was reflected in the emplacement of turbidites and olistostromes, concurrent with the uplift of a metamorphic core complex of succession I rocks. The original stratigraphic order of the successions was maintained, thus crustal imbrication was not significant. Instead, extensional faulting became important, followed by transpression on almost orthogonal fault zones, resulting in the presently observed juxtaposition of crustal blocks. The Palaeozoic sequences developed in mainly ensialic basins on Cadomian and older basement, parts of which became strongly reworked (2.6 to 0.54 Ga zircon inheritance ages) and incorporated into the Palaeozoic structures. The orogen developed either on the rifted margin of peri-Gondwana or on a rifted-away fragment of pre-Baltica. The Sudetic section of the Variscan Orogen is of broadly Alpine style, with significant basement involvement, but apparently without evidence for long-lived subduction of wide oceans or the accretion of numerous exotic terranes.


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