Cambrian successions of the Meguma Terrane, Nova Scotia, and Harlech Dome, North Wales : dispersed fragments of a peri-Gondwanan basin?

Waldron, John W.F.; Schofield, David I.; White, Chris E.; Barr, Sandra M.. 2011 Cambrian successions of the Meguma Terrane, Nova Scotia, and Harlech Dome, North Wales : dispersed fragments of a peri-Gondwanan basin? Journal of the Geological Society, 168 (1). 83-98. https://doi.org/10.1144/0016-76492010-068

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Abstract/Summary

The Meguma Terrane of Nova Scotia and the Harlech Dome of North Wales preserve similar sedimentary successions of Cambrian age. Both successions comprise a thick succession of early Cambrian sandstone turbidites, overlain by early to middle Cambrian alternating mud-rich and sand-rich units in which manganese is concentrated in two stratigraphic intervals. Above these, both successions comprise anoxic, organic-rich turbidites, shallowing upward into paler, more bioturbated Tremadocian mudstone with Rhabdinopora. Within the limited constraints of the available biostratigraphic and geochronological data, major changes in environment occurred synchronously in the two successions. Both successions show much greater similarity to each other than to adjacent successions on ‘Avalonia'. A detrital zircon analysis from the Rhinog Formation, low in the Harlech Dome succession, reveals distinct clusters of ages around 537 Ma and 2.0–2.1 Ga. A close similarity to analyses from the Meguma Terrane suggests proximity between the two terranes on the margin of Gondwana during the Cambrian Period. We suggest the term Megumia for the palaeogeographical domain that included the two successions, which was dispersed during subsequent Appalachian and Caledonian movements. These observations suggest that Megumia may have separated terranes previously regarded as parts of Avalonia. Supplementary material: U/Pb detrital zircon analytical data are available at http://www.geolsoc.org.uk/SUP18431.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1144/0016-76492010-068
Programmes:	BGS Programmes 2010 > Geology and Landscape (Wales)
ISSN:	0016-7649
Date made live:	26 Jan 2011 13:33 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/13230

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1144/0016-76492010-068

Programmes:

BGS Programmes 2010 > Geology and Landscape (Wales)

ISSN:

0016-7649

Date made live:

26 Jan 2011 13:33 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/13230