<abstract xmlns="http://www.w3.org/1999/xhtml"><p> An integrated heavy-mineral, mineral-chemical and zircon-dating study of the Triassic succession exposed on the south Devon coast, in the western part of the Wessex Basin, indicates derivation from a combination of granitic and metasedimentary lithologies of ages of mostly over 550 Ma. These sources were probably located at a relatively proximal location near the southern margin of the basin. Derivation from more distal sources in the Armorican Massif or local Variscan sources to the west appears unlikely in view of the scarcity of Permo-Carboniferous (Variscan-age) zircons. The Budleigh Salterton Pebble Bed Formation was derived from a different combination of source lithologies than the Otter Sandstone Formation, the former including staurolite-grade metasediments that were absent in the catchment area of the Otter Sandstone. The Devon coast succession has provenance characteristics that differ from equivalent sandstones further east in the Wessex Basin, and from sandstones in the East Irish Sea Basin to the north. These differences indicate that sediment supply patterns to the linked Triassic basin systems in southern Britain are complex, involving multiple distinct sub-catchment areas, and that heavy-mineral studies have considerable potential for unravelling these sub- -catchment area sources.</p></abstract>

An integrated heavy-mineral, mineral-chemical and zircon-dating study of the Triassic succession exposed on the south Devon coast, in the western part of the Wessex Basin, indicates derivation from a combination of granitic and metasedimentary lithologies of ages of mostly over 550 Ma. These sources were probably located at a relatively proximal location near the southern margin of the basin. Derivation from more distal sources in the Armorican Massif or local Variscan sources to the west appears unlikely in view of the scarcity of Permo-Carboniferous (Variscan-age) zircons. The Budleigh Salterton Pebble Bed Formation was derived from a different combination of source lithologies than the Otter Sandstone Formation, the former including staurolite-grade metasediments that were absent in the catchment area of the Otter Sandstone. The Devon coast succession has provenance characteristics that differ from equivalent sandstones further east in the Wessex Basin, and from sandstones in the East Irish Sea Basin to the north. These differences indicate that sediment supply patterns to the linked Triassic basin systems in southern Britain are complex, involving multiple distinct sub-catchment areas, and that heavy-mineral studies have considerable potential for unravelling these sub- -catchment area sources.

Heavy-mineral, mineral-chemical and zircon-age constraints on the provenance of Triassic sandstones from the Devon coast, southern Britain

HM Research Associates, 2 Clive Road, Balsall Common, CV7 7DW, UK and CASP, University of Cambridge, Cambridge CB3 0DH, United Kingdom

Centre for Environmental Magnetism and Palaeomagnetism, Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YW, United Kingdom

Central Analytical Facility, Stellenbosch University, Chamber of Mines Building, Matieland 7602, South Africa

Geologos

An integrated heavy-mineral, mineral-chemical and zircon-dating study of the Triassic succession exposed on the south Devon coast, in the western part of the...

Heavy-mineral, mineral-chemical and zircon-age constraints on the provenance of Triassic sandstones from the Devon coast, southern Britain

Pubblicato online: 31 mag 2013

Pagine: 67 - 85

DOI: https://doi.org/10.2478/logos-2013-0005

This content is open access.