The Geology of Ore Deposits (Classic Reprint)

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Excerpt from The Geology of Ore DepositsThe original source of all ore deposits lay in the primitive igneous crust of the earth and in those igneous rocks which subsequently penetrated it from the interior. It may thus be said that the source of all ore deposits may ultimately be traced to rocks with igneous characteristics.The igneous rocks which carry, or are answerable for, the richest metalliferous masses are mainly those of the larger intrusions. These are deep-seated or plutonic in Character, by which is meant that they never reached the earth's surface in a ¿uid state, but were covered to a considerable depth at the time of their consolidation. Generally speaking, the older igneous intrusions - that is to say, those which belong to the pre-cambrian and Palaeozoic periods - are richer in ore deposits than those which have been intruded at a later date.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.