Robert A. Christman, 1972. "Volcanic Geology of Southwestern Antigua, B.W.I.", Studies in Earth and Space Sciences, R. Shagam, R. B. Hargraves, W. J. Morgan, F. B. Van Houten, C. A. Burk, H. D. Holland, L. C. Hollister
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The mountainous southwestern portion of Antigua consists mostly of calcalkaline igneous rocks, ranging in composition from quartz basalt to dacite, with andesite being most common. These are associated with agglomerates, tuffs, and a few limestone lenses which have been dated as mid-Oligocene. A small area of quartz diorite suggests that the center of volcanic activity was just to the south of the island and that a considerable thickness of pyroclastics has been eroded from the southern part of the island to expose the roots of the volcanoes which were active in mid-Oligocene time. The relation of the geologic events in the Lesser Antilles to the present theories of ocean-floor spreading is discussed briefly.