Meguma terrane
{{short description|Terrane exposed in southern Nova Scotia}}
Image:Terranes of Nova Scotia.PNG, showing how the Meguma terrane forms the southern portion.]]
The Meguma terrane, also known as Megumia, is a terrane exposed in southern Nova Scotia, that became joined to the present North American landmass as part of the Appalachian orogeny.
The exposed part of the Meguma terrane, the Meguma Group, is largely composed of {{Circa}} {{Convert|10|km|abbr=on}} thick Cambrian to Ordovician turbidites that have been interpreted as submarine fan deposits.{{Harvnb|Waldron|White|MacInnes|Roselli|2005|loc=Maguma Terrane in Nova Scotia, p. 4}} The Meguma terrane is joined to the Avalon terrane along the Minas Fault Zone, which runs east–west from Chedabucto Bay to Cobequid Bay and the Minas Basin.{{Harvnb|Sangster|Smith|2007|loc=Regional Geology and Tectonic Setting, pp. 724–725}} The Meguma Group is intruded by numerous Devonian and Carboniferous plutons.{{Harvnb|Horne|Culshaw|White|Kontak|2007}}
The extent of the formation is unclear; some geologists believe that a magnetic anomaly along the coast of Cape Cod may represent a suture between the Meguma and Avalon terranes in that region.{{Harvnb|Hallett|Paskevich|Poppe|Brand|2003|loc=Geologic setting}} Unlike the Avalon terrane, the Meguma terrane has not been definitely associated with a territory on the other side of the Atlantic. It may be represented in either the Galicia-Tras-Os-Montes Zone in Spain and Portugal;{{Citation needed|date=February 2018}} the West African Craton in Morocco; or the Amazonian Craton.{{Harvnb|Nance|Gutiérrez-Alonso|Keppie|Linnemann|2010|p=211}} Meguma was, nevertheless, part of Gondwana during the Cambrian, and possibly formed a single peri-Gondwanan fragment together with Avalon. Meguma then became shortened during the Acadian orogeny but Avalon somehow escaped those Acadian deformations.{{Harvnb|Waldron|White|MacInnes|Roselli|2005|loc=History of the Avalon-Meguma Boundary, p. 5}}
Geologically this area is of interest not only to students of geological history, but because metamorphism produced gold deposits which were mined extensively (up to {{Convert|30000|ozt/yr|kg/yr|abbr=on}}) in the latter half of the 19th century, and which remain potentially exploitable today during periods of higher gold prices.{{Harvnb|Sangster|Smith|2007|loc=Introduction and history, pp. 723–724}}
See also
- {{annotated link|Ganderia|aka=Gander terrane}}
- {{annotated link|Rheic Ocean}}
References
; Notes
{{Reflist}}
; Sources
{{Refbegin}}
- {{Cite web
| last1 = Hallett | first1 = B. W.
| last2 = Paskevich | first2 = V. F.
| last3 = Poppe | first3 = L. J.
| last4 = Brand | first4 = S. G.
| last5 = Blackwood | first5 = D. S.
| title = A Pictorial Survey of the Bedrock beneath Western Cape Cod, Massachusetts
| year = 2003 | publisher = United States Geological Survey | work = Open-File Report OF-2003-221
| url = http://pubs.usgs.gov/of/2003/of03-221/htmldocs/intro.htm | access-date = 3 February 2018
}}
- {{Cite conference
| last1 = Horne | first1 = R. J.
| last2 = Culshaw | first2 = N.
| last3 = White | first3 = C. E.
| last4 = Kontak | first4 = D.
| title = Neoacadian deformation within the Meguma terrane
| year = 2007 | conference = Northeastern Section - 42nd Annual Meeting | publisher = Geological Society of America | volume = 39 | page = 69
| url = https://gsa.confex.com/gsa/2007NE/finalprogram/abstract_118500.htm | access-date = 3 February 2018
}}
- {{Cite journal
| last1 = Nance | first1 = R. D.
| last2 = Gutiérrez-Alonso | first2 = G.
| last3 = Keppie | first3 = J. D.
| last4 = Linnemann | first4 = U.
| last5 = Murphy | first5 = J. B.
| last6 = Quesada | first6 = C.
| last7 = Strachan | first7 = R. A.
| last8 = Woodcock | first8 = N. H.
| title = Evolution of the Rheic ocean
| year = 2010 | journal = Gondwana Research | volume = 17 | issue = 2–3 | pages = 194–222
| url = https://www.researchgate.net/publication/223716583 | access-date = 3 February 2018
| doi = 10.1016/j.gr.2009.08.001 | bibcode = 2010GondR..17..194N
}}
- {{Cite book
| last1 = Sangster | first1 = A. L.
| last2 = Smith | first2 = P. K.
| chapter = Metallogenic summary of the Meguma gold deposits, Nova Scotia
| title = Mineral deposits of Canada: a synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods
| editor-last = Goodfellow | editor-first = W. D.
| year = 2007 | publisher = Geological Association of Canada, Mineral Deposits Division | series = Special Publication | volume = 5 | pages = 723–732
| chapter-url = http://nsgoldcorp.com/wordpress/wp-content/uploads/2011/04/Leipegate_Meguma1-2.pdf | access-date = 3 February 2018
}}
- {{Cite book
| last1 = Waldron | first1 = J. W.
| last2 = White | first2 = J. C.
| last3 = MacInnes | first3 = E.
| last4 = Roselli | first4 = C. G.
| title = Field Trip B7: Transpression and transtension along a continental transform fault: Minas Fault Zone, Nova Scotia
| year = 2005 | publisher = Atlantic Geoscience Society | series = AGS Special Publication | volume = 33
| url = https://dalspace.library.dal.ca/bitstream/handle/10222/53771/AGS%2333_FieldTripB7MinasFaultZone.pdf
| hdl = 10222/53771 | isbn = 9780973798227 }}
{{Refend}}
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Category:Natural history of North America
Category:Landforms of Nova Scotia
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