The Ore Magmas: a Series of Essays on Ore Deposition

Abstract

THESE two interesting and suggestive volumes consist of essays on ore deposits based on Mr. J. E. Spurr's varied personal experience of American mines, which include so many types that they illustrate the chief phenomena of ore formation. Mr. Spurr shows in this work the clearness of insight, caution, and scientific ability which have made his contributions to economic geology of special value. He was one of the pioneers of the school which attaches predominant importance to igneous action in the formation of ores. He emphatically rejects lateral secretion or the formation of ores by surface waters, and also by the agency of deep-seated hot springs, as no water circulation could explain such facts as the enormous concentration of copper ores in Arizona. He insists, moreover, that ores have been made by processes that do not operate in any accessible zone of the crust, as he has not seen in the deepest mine visited any lode in process of growth. The Ore Magmas: a Series of Essays on Ore Deposition. By J. E. Spurr. Vol. 1. Pp. x + 430. Vol. 2. Pp. ix + 431–915. (London: McGraw-Hill Publishing Co., Ltd., 1923.) 2 vols., 40s.