Northeast GSA 2007: NE Mssachusetts Plutons

On this field trip we looked at plutons in three different tectonic domains in eastern New England: the Avalon Terrane just north of Boston, the Nashoba Terrane to the west, and the Merrimack-Central Maine Terrane to the north of that. These three regions have different stratigraphy, had different metamorphic histories, and experienced different varieties and episodes of igneous activity, until they were finally assembled in the mid-Paleozoic. The slightly ambitious itinerary permitted us to visit seven of the 11 scheduled stops. For details see the reference below.

Stop 1Cape Ann Granite
Stop 3Co-mingling mafic magma and Beverly Syenite
Stop 4More Beverly Syenite
Stop 5Salem Highland composite mafic pluton
Stop 7Danvers alkali gabbro and cumulate syenites
Stop 9Newbury Volcanics
Stop 10Sharpners Pond quartz diorite

Principal reference

Hon, R., Hepburn, J.C., Laird, Jo., 2007, Siluro-Devonian igneous rocks of the easternmost three terranes in southeastern New England: examples from NE Massachusetts and SE New Hampshire: Field Trip F4, p. 23-43, in Thompson, P.J., editor, Guidebook to Field Trips in New Hampshire and Adjacent Maine and Massachusetts, Geological Society of America, Northeastern Section, field trip guidebook for the 42nd annual meeting, Durham, NH.