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Gondwana

About: Gondwana is a research topic. Over the lifetime, 6078 publications have been published within this topic receiving 263050 citations. The topic is also known as: Gondwanaland.


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Journal ArticleDOI
01 Nov 1985-Geology
TL;DR: The Devonian-early Carboniferous sequence in the eastern Anti-Atlas represents a complete record of the last stage of the depositional and tectonic evolution along the northwestern margin of Gondwana.
Abstract: The Devonian–early Carboniferous sequence in the eastern Anti-Atlas represents a complete record of the last stage of the depositional and tectonic evolution along the northwestern margin of Gondwana. As a consequence of early Variscan block faulting, a platform and basin topography was established during the Middle and Late Devonian. Platforms were covered by condensed cephalopod limestones; sedimentation in the basins was mainly argillaceous with calcareous and turbiditic intercalations. In the latest Famennian/early Tournaisian the whole area was covered by delta deposits in the south passing into turbidites and olistostromes toward a continental slope farther north. This sedimentary and structural evolution reflects the gradual foundering and disintegration of the northwestern continental margin of Gondwana prior to the collisional stage in the late Visean/late Carboniferous.

108 citations

Journal ArticleDOI
TL;DR: In this paper, the authors show that the Cuvette Centrale (Central Basin) of Zaire is an infra-Cambrian to recent basin with up to 9 km of sedimentary section.
Abstract: The Cuvette Centrale (Central Basin) of Zaire is an infra-Cambrian to Recent basin with up to 9 km of sedimentary section. Basin subsidence can be largely explained by a postulated Late Proterozoic failed rift and subsequent thermal relaxation. Seismic reflection profiles and well data reveal a Palaeozoic development of the basin punctuated by two regional deformational episodes; one in the Early Palaeozoic (Late Cambrian) and a second in the Late Palaeozoic (Late Permian-Triassic). Both episodes result from NE-SW contraction, with the Late Palaeozoic episode being largely a reactivation of the Early Palaeozoic structures. The timing of the two deformations correlates with collisional events at continental margins some distance from the Congo Basin. In the Early Palaeozoic the deformation appears to be related to the late stages of the West Congolian fold and thrust belt and coincides regionally with the Pan-African event sensu stricto. The Late Palaeozoic deformation coincides with collisional tectonics along the southern margin of Gondwana and the generation of the Cape and Sierra Ventana Foldbelts. It is postulated that in both the Early and Late Palaeozoic, Africa and Gondwana experienced widespread intracontinental deformation generated by distant collisional processes much as Central Asia is experiencing today.

108 citations

Journal Article
TL;DR: The Cordubian Series of West Gondwana is a sub-trilobitic lower Cambrian of the Cambrian as discussed by the authors, which is defined by the lowest occurrence of diagnostic Cambrian ichnogenera in central Spain, and is comparable to the Placentian series of Avalon.
Abstract: Similarities in biotic successions support a unified, composite chronostratigraphy for the Lower-Middle Cambrian of the Iberian and Moroccan margins of West Gondwana. The Cordubian Series (emended from an Iberian stage-level unit) comprises the sub-trilobitic Lower Cambrian of West Gondwana. This series represents ca. half of the Cambrian (ca. 25 m.y.), has a base defined at the lowest occurrence of diagnostic Cambrian ichnogenera in central Spain, and is comparable to the Placentian Series of Avalon. The overlying trilobite-bearing Lower Cambrian (ca. 9 m.y. duration), or Atlasian Series (new), of West Gondwana consists of two stages originally defined in highly fossiliferous (trilobites and archaeocyaths) Moroccan sections where they have great potential for precise U-Pb geochronology. The penultimate Lower Cambrian stage, the Issendalenian, with the near-joint lowest occurrence of trilobites and archaeocyaths, is approximately comparable with the sparsely fossiliferous, Iberian "Ovetian Stage" (designation abandoned). The "Ovetian" as currently revised is invalid because it is an objective homonym of SDZUY’s original “Ovetian.” The "Ovetian" is not a practically applicable unit as its basal stratotype horizon lacks any identified fossils, and its trilobites are so rare that it cannot serve as a standard for interregional correlation. By contrast, the Banian Stage as defined in Morocco is suitable as the terminal Lower Cambrian stage of West Gondwana. It is based on very fossiliferous successions that allow recognition of three successive trilobite zones and is similar in concept to the Iberian “Marianian Stage” (designation abandoned). The “Marianian” lacks a designated lower boundary stratotype locality, lacks a biostratigraphically defined base at a stratotype, and is so sparsely fossiliferous that no biostratigraphic zonation exists. Long-term problems involving regional definition of the West Gondwanan Lower–Middle Cambrian boundary are resolved. The lowest occurrence of paradoxidid trilobites, the classic index for the base of the Middle Cambrian, is diachronous in West Gondwana and other regions, with the group showing a delayed appearance in Iberia, Sweden, and Bohemia, by comparison with Morocco. Taxonomic revision of Iberian trilobites and new documentation of their ranges in Morocco show that the Iberian terminal “Lower Cambrian” “Bilbilian Stage” (designation abandoned) correlates with the Moroccan upper Banian and lower and middle “Tissafinian” Stages and with the Siberian upper Toyonian (traditionally assigned to the Lower Cambrian in Siberia) and lower Amgan (assigned to the Middle Cambrian in Siberia) Stages. The “Bilbilian” thus includes Middle Cambrian strata in a traditional international concept. Faunas from the base of the Iberian “lowest” Middle Cambrian “Leonian Stage” (designation abandoned) correlate largely into the second trilobite zone of the “Tissafinian” and are now understood to appear above an intra-Middle Cambrian faunal break. This faunal break is still poorly understood and may be an artifact of collection failure immediately above the sparsely fossiliferous, problematical “Valdemiedes event” interval. The base of this “Middle Cambrian”, now termed Celtiberian Series (new designation), in West Gondwana is best defined by the base of the lower Middle Cambrian Agdzian Stage (new designation). The Agdzian includes the “Tissafinian” and overlying lower “Toushamian Stage” designations abandoned) of Morocco, and has its top defined by the base of the middle Middle Cambrian Caesaraugustian Stage, as defined in Spain at the lowest occurrence of Badulesia tenera. The Languedocian, originally defined at the lowest occurrence of Solenopleuropsis (Manublesia) thorali in the southern Montagne Noire of France comprises the third, and terminal stage of the Celtiberian Series. We suggest that the designations “Lower Cambrian” and “Middle Cambrian” be regarded as descriptive and nonchronostratigraphic terms in discussions of the Cambrian. New taxa or taxonomic combinations include Myopsolenites altus (LINAN & GOZALO, 1986), M. boutiouiti sp. nov., M. kielciensis (BEDNARCZYK, 1970), and Hamatolenus ( Hamatolenus ) vincenti sp. nov.

107 citations

Journal ArticleDOI
TL;DR: The Estremoz Anticline in the Ossa-Morena Zone (SW Iberia) includes upper Ediacaran detrital rocks unconformably overlain by lower Cambrian carbonate and carbonate rocks as discussed by the authors.

107 citations

Journal ArticleDOI
TL;DR: Early Permian black pyritic shale units, such as the Whitehill, Irati and Huab formations and Black Rock Member, in southwestern Gondwana basins, have elevated δ13C values of total organic carbon up to −17

107 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023269
2022497
2021307
2020281
2019293
2018230