Carrock Fell: a Study in the Variation of Igneous Rock-Masses.—Part II. The Carrock Fell Granophyre. Part III. The Grainsgill Greisen

Open Access
Publisher Website
Google Scholar
Abstract
9. I ntroduction . I n a former paper I have given a general sketch of the geology T of the Carrock Fell district, and discussed the remarkable variations observed in the gabbro which is there exposed. The present communication deals with the granophyre, which is closely associated with that gabbro, and with another interesting acid rock, not far distant, but belonging to a different group of intrusions. The granophyre occurs in several distinct masses, which, from their general eye-shaped outcrop and parallelism of strike with the adjacent rocks, must be regarded as laccolitic intrusions (see sketchmap, F1. IV.). The similarity of these neighbouring masses justifies us in considering them as a connected group. The one most easily studied is that which builds Carrock Fell itself, and extends westward in a tongue nearly as far as Round Knott. The exposures about: Rae Crags, farther north-west, probably belong to a mass distinct from the preceding, separated from it by diabase, and faulted ou the north against the Eycott Hill lavas and the Drygill Shales. Granophyre is seen at certain points o~ the moorland of which Great Lingy is the centre: if these outcrops belong to one connected mass, its extent from Roughten Gill eastward must be nearly 2 miles. There are smaller intrusions in Arm o' Grain and other gills, but we may confine our attention chiefly to the mass first indicated, which is well exposed about Carrock Fell and the Pike and in the cliffs known as the Scurth. The question

This publication has 0 references indexed in Scilit: