2012
DOI: 10.1139/e11-012
|View full text |Cite
|
Sign up to set email alerts
|

Tectonic significance of Late Ordovician silicic magmatism, Avalon terrane, northern Antigonish Highlands, Nova Scotia 1 This article is one of a series of papers published in CJES Special Issue: In honour of Ward Neale on the theme of Appalachian and Grenvillian geology.2 Contribution to International Geological Correlation Programme (IGCP) Project 497.

Abstract: Avalonia was a microcontinent during most of the Ordovician, separating the Iapetus Ocean to the north from the Rheic Ocean to the south. In the northern Antigonish Highlands, Nova Scotia, volcanic rocks (Dunn Point and McGillivray Brook formations) underlie Early Silurian -Early Devonian strata (Arisaig Group) and were thought to represent extension that heralded the development of the basin into which Arisaig Group strata were deposited. However, recent U-Pb (zircon, thermal ionization mass spectrometry) dat… Show more

Help me understand this report

Search citation statements

Order By: Relevance

Paper Sections

Select...
1
1
1
1

Citation Types

0
7
0

Year Published

2012
2012
2024
2024

Publication Types

Select...
8

Relationship

0
8

Authors

Journals

citations
Cited by 29 publications
(7 citation statements)
references
References 89 publications
0
7
0
Order By: Relevance
“…90 Ma (Tables DR1 and DR2). Cambrian-Ordovician ages are common in Avalonian sedimentary and metasedimentary rocks but are also consistent with plutonic rocks in the Avalon and Gander terranes [34,67,69,70]. The oldest concordant inherited zircon from the anorthosite dyke has a 206 Pb/ 238 U age of 657 ± 15 Ma (1σ) which is more indicative of the Avalon terrane than the Gander terrane [59].…”
Section: Whole-rock Geochemistrymentioning
confidence: 55%
See 1 more Smart Citation
“…90 Ma (Tables DR1 and DR2). Cambrian-Ordovician ages are common in Avalonian sedimentary and metasedimentary rocks but are also consistent with plutonic rocks in the Avalon and Gander terranes [34,67,69,70]. The oldest concordant inherited zircon from the anorthosite dyke has a 206 Pb/ 238 U age of 657 ± 15 Ma (1σ) which is more indicative of the Avalon terrane than the Gander terrane [59].…”
Section: Whole-rock Geochemistrymentioning
confidence: 55%
“…The oldest age group consists of two subgroups where four of the zircons are between 440 ± 11 Ma (1σ) and 446 ± 11 Ma (1σ), and the remaining two are 464 ± 11 Ma (1σ) and 468 ± 11 Ma (1σ). This group is considered to be inherited due to their relatively minor abundance but also because middle to late Ordovician rocks are known in Cape Breton and throughout Avalonia [33,34]. We interpret the crystallization age to be indicative of the weighted-mean 206 Pb/ 238 U age (423:8 ± 2:5 Ma, 2σ) of the zircons that comprise the middle group ( Figure 5(b)).…”
Section: Resultsmentioning
confidence: 99%
“…There are several other known Ordovician Avalonian terranes that have comparable magmatism and originated in similar tectonic settings to the Welsh marginal basin rocks. Similar terranes from the southern flank of the Iapetus include the Antigonish Highlands Avalonian terrane in Nova Scotia, Canada, and the Avoca volcanic rocks, Ireland; both formed owing to rifting within an overall arc environment (McConnell, Stillman & Hertogen, 1991; Murphy, Hamilton & LeBlanc, 2011). These comparable origins, therefore, reinforce the suggested model of formation for the Fishguard Volcanic Group.…”
Section: Discussionmentioning
confidence: 99%
“…Avalonia (the microcontinent of which Wales was a part) moved northward from 55°S to 30°S in the period from the Arenig (478–467 Ma) to the Ashgill (451–444 Ma) (Fitton, Thirlwall & Hughes, 1982). During this period a number of island arc chains and marginal basins formed above the southeastward-dipping subduction zone on the north side of Avalonia along a NE-trending plate margin (Fitton & Hughes 1970; Phillips, Stillman & Murphy, 1976; Fitton, Thirlwall & Hughes, 1982; Murphy & Nance, 2008; Murphy, Hamilton & LeBlanc, 2011). Ordovician sequences of both basic and/or silicic lavas are present not only in the Fishguard region but throughout Wales, in areas such as Snowdonia and Ramsey Island (Fig.…”
Section: Introductionmentioning
confidence: 99%
“…These felsic rocks have compositions similar to A-type granites and were interpreted to represent on-going extension following on from that represented by the West Barneys River plutonic suite at ca. 469 Ma (Escarraga et al 2012;Murphy et al 2012). The syenitic suite and metarhyolite in the Cape Porcupine Complex appear to extend this period of A-type extensional and bimodal magmatism in this part of Avalonia back to at least 478 Ma.…”
mentioning
confidence: 97%