The Pangaean inheritance

• Autores: C. R. Twidale, Juan Ramón Vidal Romaní
• Localización: Cadernos do Laboratorio Xeolóxico de Laxe: Revista de xeoloxía galega e do hercínico peninsular, ISSN 0213-4497, Nº 19, 1994, págs. 7-36
• Idioma: inglés
• Títulos paralelos:
  • La herencia de Pangea
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• Dialnet Métricas: 1 Cita
• Resumen

  • Very old palaeosurfaces have been identified and dated in several parts of the former Gondwana and Laurasia. In Australia the separation from Antarctica was complete by the end of the Eocene so that any surface of earliest Tertiary and certainly of Mesozoic age can be regarded as Gondwanan. Similarly, in the Northern Hemisphere, Laurasia existed from the end ofthe Carboniferous to the Jurassic so that any landscape elements older than Jurassic can be regarded as Laurasian. The ages of these ancient surfaces have been determined in various ways and with various degrees of confidence, but correlative deposits associated with the widespread Early Cretaceous marine transgression, and the relationship of land surfaces to Cretaceous shorelines and Early Tertiary volcanic extrusions, or regolithic veneers have proved especially useful. Faulting of known age has also been used though it tends to give dates that are too young for the dislocated surfaces.

    Many exhumed surfaces have been preserved by burial, but epigene-etch features like those of the Gawler Ranges, Hamersley Ranges and the Arnhemland Massif (Kakadu) have stood as uplands throughout the Cainozoic with little change. The same is true of the remnants of planation surfaces of the Iberian elements of the Hesperian Massif. Epigene-etch surfaces of Mesozoic age are also reported from southern and West Africa, from southern India and from the Guyana Craton ofSouth America. In addition, epigene-etch features, as well as exhumed features of various ages, are, increasingly, being recognised from the Laurasian components of Pangaea, for instance in the Linares-Ubeda region in the south of Iberian Peninsula, so that it is possible to refer to the Pangaean inheritance.

    These survival can in sorne measure be explained in terms of their being uplands, but obviously the conventional models of landscape evolution need to be reconsidered.