Cape Woods Pluton

Unit Name: Cape Woods Pluton
Unit Type: Lithodemic
Rank: Lithodeme
Status: Formal
Usage: Currently in use
Age Interval: Middle Devonian (397.5 - 385.3 ma)
Age Justification: Geochronology. Regression analysis of four zircon fractions, which included a significant proportion of xenocrystic material, yielded intercept ages of 369 +1/-5 Ma and ca. 1360±200 Ma. The best estimate for the crystallization of the pluton was given by a sphene age of 390±10 Ma (Trettin et al., 1987), Eifelian according to the adopted time scale, with confidence limits in the Early and Middle Devonian. A K-Ar (biotite) determination of 352±15 Ma (recalculated from Wanless et al., 1974; earliest Carboniferous, with confidence limits in the Late Devonian and Early Carboniferous) reflects cooling (Trettin, 1998).
Province/Territory: Nunavut

Originator: Frisch, 1974.

Type Locality:

Northwestern Wootton Peninsula, northern Ellesmere Island (Trettin, 1998).

Distribution:

It is a batholith underlying about 166 km² (Trettin, 1998).

Lithology:

Medium grained biotite-quartz monzonite or granodiorite with abundant K-feldspar phenocrysts (Trettin, 1998).

Age Determinations:

Method - K/Ar; Material - Biotite; Age - 352; Err_Minus - 15; Err_Plus - 15..

Age - 390; Err_Minus - 10; Err_Plus - 10..

Material - Zircon; Age - 369; Err_Minus - 5; Err_Plus - 1..

Relationship:

It intrudes schist and minor marble and quartzite. The country rocks are generally of greenschist grade, but sillimanite, kyanite, and staurolite are developed in the contact aureole (Trettin, 1998).

References:

Frisch, Thomas, 1974. Metamorphic and plutonic rocks of northernmost Ellesmere Island, Canadian Arctic Archipelago; Geological Survey of Canada, Bulletin 229, 87 p.

Trettin, H.P., 1998. Pre-carboniferous geology of the northern part of the Arctic Islands; Geological Survey of Canada, Bulletin 425, 401 p.

Trettin, H.P., Parrish, R., and Loveridge, W.D., 1987. U-Pb age determinations of Proterozoic to Devonian rocks from northern Ellesmere Island, Arctic Canada. Canadian Journal of Earth Sciences, v. 24, p. 246-256.

Wanless, R.K., Stevens, R.D., Lachance, G.R., and Delabio, R.N., 1974. Age determinations and geological studies, K-Ar isotopic ages, report 12; Geological Survey of Canada, Paper 74-2, 72 p.

Source: CSPG Lexicon of Canadian Stratigraphy, Volume 1, Arctic Archigelage (District of Franklin); R.L. Christie, A.F. Embry, G.A. Van Dyck (editor)
Contributor: K. Dewing; Michael Pashulka
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 18 Aug 2009