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The age of the Lugar sill and a discussion of the Late-Carboniferous/Early-Permian sill complex of S.W. Scotland

✍ Scribed by C. M. B. Henderson; K. A. Foland; F. G. F. Gibb

Book ID
102845333
Publisher
John Wiley and Sons
Year
1987
Tongue
English
Weight
578 KB
Volume
22
Category
Article
ISSN
0072-1050

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✦ Synopsis

The incremental heating 40Ar/39Ar method has been used to date a kaersutite separate from the main theralite-picrite unit of the Lugar sill. Ar-release spectra show discordance mainly due to the presence of excess Ar in alteration phases intimately associated with the primary kaersutite. Plateaus in the spectra allow an emplacement age of 288 5 6 Ma (20) to be assigned to the sill. The results are used to discuss the age relations of the alkaline Permo-Carboniferous sill complex of southwest Scotland. It is concluded that these sills could have been emplaced over a shorter period of time than implied by the available conventional KlAr data. The classification of the alkaline sills into kylite and teschenite types has little petrogenetic significance.

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