The Caledonian Heilhornet Pluton, north-central Norway: geological setting, radiometric age and implications for the Scandinavian Caledonides

Autor:	Ø. Nordgulen, B. Schouenborg
Rok vydání:	1990
Předmět:	Pluton engineering Ordovician Geochemistry Geology Thrust fault engineering.material Devonian Hornblende Nappe Zircon Petrogenesis
Zdroj:	Journal of the Geological Society. 147:439-450
ISSN:	2041-479X 0016-7649
Popis:	The Heilhornet Pluton is a medium-sized ( c . 50 km 2 ), sub-circular, discordant intrusion which penetrates the thrust zone separating the Helgeland Nappe Complex from paragneisses in the Vestranden region, north-central Norway. The intrusion consists of biotite ± hornblende granite and ranges in composition from 61.5 to 72.5 wt.% Si0 2 The initial Sr-ratio ( c . 0.7070) shows that crustal sources have been involved in the petrogenesis of the granite. A U-Pb zircon age of 444 ± 11 Ma for the pluton indicates that juxtaposition of the nappe complex with metasedimentary rocks in Vestranden took place prior to or during the late Ordovician. A consequence of this is that the general correlation of the metasedimentary rocks in Vestranden with the Seve Nappes must be revised. Final eastward thrusting of the complex, together with a yet unknown part of the Vestranden supracrustal sequence, probably took place during the middle Silurian to early Devonian, Scandian, orogenic event.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::c215e1a36593ddff160d11539bf94aff https://doi.org/10.1144/gsjgs.147.3.0439 Zobrazit plný text záznamu