The Christmas Cove Dyke of coastal Maine, USA, and regional sources for Early Mesozoic flood basalts in northeastern North America

Auteurs-es

  • James Gregory McHone
  • Arthur M. Hussey Department of Earth and Oceanographic Science, Bowdoin College
  • David P. West Department of Geology, Middlebury College
  • David G. Bailey Department of Geosciences, Hamilton College

DOI :

https://doi.org/10.4138/atlgeo.2014.004

Mots-clés :

basalt, dyke, Early Mesozoic, CAMP, rift basins

Résumé

 

A large Early Mesozoic quartz tholeiite dyke has been mapped discontinuously for 190 km in southern coastal Maine, USA. Including its type locality at Christmas Cove (South Bristol, Maine, USA), the dyke has features of a generally ENE strike; dip usually steep to the SSE but abruptly turning very shallow in short sections; and widths of 9 to 35 m. The dyke rock has a distinctive cross-columnar field appearance, and a subophitic to micro-porphyritic texture with abundant Ti-bearing augite, calcic plagioclase, scattered euhedral orthopyroxene phenocrysts, and coarse-grained glomerophyric clumps of augite with plagioclase. Several 40Ar/39Ar whole-rock dates for this and associated regional dykes are close to 201 Ma, in agreement with ages of other Early Mesozoic dykes and basalts of the Central Atlantic Magmatic Province (CAMP). The geographic position, age, whole-rock chemistry, and petrography indicate that the Christmas Cove Dyke is co-magmatic or contiguous with the Higganum-Holden Dyke of southern New England, which was a source for the Talcott Basalt of the Early Mesozoic Hartford rift basin. The dyke system is a 700-km long fissure source for the earliest rift basin basalts preserved in northeastern North America, and it virtually connects the Hartford Basin and the Fundy Basin in Atlantic Canada. The Caraquet Dyke of New Brunswick and central Maine may be co-magmatic with the Buttress Dyke and Holyoke Basalt of southern New England, but lava from it is not preserved in Atlantic Canada or Maine.

 

Biographie de l'auteur-e

James Gregory McHone

retired professional geologist

Téléchargements

Publié-e

2014-04-29

Comment citer

McHone, J. G., Hussey, A. M., West, D. P., & Bailey, D. G. (2014). The Christmas Cove Dyke of coastal Maine, USA, and regional sources for Early Mesozoic flood basalts in northeastern North America. Atlantic Geoscience, 50, 66–90. https://doi.org/10.4138/atlgeo.2014.004

Numéro

Vol. 50 (2014)

Rubrique

Articles

Licence

As of January 1, 2025, Atlantic Geoscience is adopting Creative Commons Attribution 4.0 International (CC BY 4.0)  This license requires that re-users give credit to the creator. It allows re-users to distribute, remix, adapt, and build upon the material in any medium or format, even for commercial purposes.

Copyright to material published in Atlantic Geoscience is normally retained by the author.  Alternate arrangements can be made on request for government employees.

Permission to use a single graphic for which the author owns copyright is considered “fair dealing” under the Canadian Copyright Act and “fair use” by the journal, and no other permission need be granted, subject to the image being appropriately cited in all reproductions. The same fair dealing/fair use policy applies to sections of text up to 100 words in length.