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Titolo: Silurian provenance variation in the Southern Uplands terrane, Scotland, assessed using neodymium isotopes and linked with regional tectonic evolution
Autore: Stone, P; Evans, JA;
- Indirizzi:
- British Geol Survey, Edinburgh EH9 3LA, Midlothian, Scotland British Geol Survey Edinburgh Midlothian Scotland EH9 3LA thian, Scotland
- Titolo Testata:
- TRANSACTIONS OF THE ROYAL SOCIETY OF EDINBURGH-EARTH SCIENCES
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volume: 91,
anno: 2001,
parte:, 3-4
pagine: 447 - 455
- SICI:
- 0263-5933(2001)91:<447:SPVITS>2.0.ZU;2-P
- Fonte:
- ISI
- Lingua:
- ENG
- Soggetto:
- FORELAND BASIN; ACCRETIONARY PRISM; IAPETUS SUTURE; NORTHERN BELT; BACK-ARC; SM; GEOCHEMISTRY; CALEDONIDES; PATTERNS; SEDIMENTS;
- Keywords:
- Gala Group; greywacke; Hawick Group; Iapetus Ocean; Lake District; Midland Valley;
- Tipo documento:
- Article
- Natura:
- Periodico
- Settore Disciplinare:
- Physical, Chemical & Earth Sciences
- Citazioni:
- 41
- Recensione:
- Indirizzi per estratti:
- Indirizzo: Stone, P British Geol Survey, Murchison House, Edinburgh EH9 3LA, Midlothian, Scotland British Geol Survey Murchison House Edinburgh Midlothian Scotland EH9 3LA
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- Citazione:
- P. Stone e J.A. Evans, "Silurian provenance variation in the Southern Uplands terrane, Scotland, assessed using neodymium isotopes and linked with regional tectonic evolution", T RS EDIN-E, 91, 2001, pp. 447-455
Abstract
The progressive changes in the provenance of Silurian greywacke turbiditesin the Southern Uplands terrane reflect geotectonic events at the Laurentian continental margin during closure of the Iapetus Ocean. In the northern Gala Group, juvenile andesitic detritus in some beds gives epsilon Nd values no lower than -4.2, more commonly, quartzo-feldspathic greywackes have epsilon Nd values in the -5.5 to -6.7 range, produced by the mixing of juvenile plutonic and Proterozoic basement detritus during are unroofing. In the southern (younger) Gala Group, Proterozoic epsilon Nd values range down from -7.7 to -11.2 with only sporadic evidence for a juvenile component. An abrupt change is seen between the Gala Group and its tectonostratigraphical successor, the Hawick Group. In the latter, epsilon Nd values have a compactrange between -4.7 and -6.6, indicating the renewed dominance of a more juvenile, plutonic provenance. Regional variations in the Sr/Rb ratio suggestthat this was more evolved than the source of the Gala Group plutonic material. The Wenlock greywackes of the Riccarton Group have epsilon Nd values in the range -5.1 to -7.8, overlapping with the Hawick Group and with coeval greywackes from both the Midland Valley and Lakesman terranes. Overall, the data support proposals that the Iapetus Ocean had effectively closed by mid-Silurian times. Conversely, data from greywacke boulders in the basal Old Red Sandstone conglomerate of the Midland Valley terrane militate against its Wenlock juxtaposition with the Southern Uplands.
ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 18/05/13 alle ore 16:23:59