Tis text has resulted from some forty years of experience during which the author has puzzled over the meaning of ore textures. Te learning process has been slow and is still incomplete. Te bemusement began directly upon leaving the academic confnes, which in retrospect lef one keen young geologist very ill-equipped to interpret the mineralising process via feld or hand lens style observation of the rocks. Enlightenment has proceeded via a series of events:- 1. Te slow process of feld observation as an industry-based mine and exploration geologist. 2. Te opportunity to visit numerous diferent styles of ore deposit both as an academic and consultant. 3. Te need to answer questions from several generations of enquiring students. 4. Te privilege of being able to conduct research. 5. Te good fortune to be associated with a few top class economic geologists who actually knew what they were doing! Professor Willard C. Lacy deserves the most credit for quietly demonstrating the value of frst principles concerning fuid channelways, combined with an ability to look properly at the t- tures. Despite rapid technological advances this skill remains fundamental both to the practi- ing exploration geologist and to the academic researcher who is interested in understanding ore forming processes. Te fve volumes comprising this presentation were originally compiled individually over a period of eleven years, and aimed to progressively guide the observer though the principles of recogn-i tion concerning infll, alteration, overprinting, and fnally to ore-related breccias.
Understanding ore textures is fundamental to unraveling the genesis of an ore deposit, which in turn allows exploration and mining geologists to build their conceptual models of the deposits they encounter and leads to more successful exploration and exploitation. This book is specifically designed for the field geologist working without the benefits of sophisticated chemical, mineralogical or petrological support. It covers the basic building blocks of textural recognition beginning with infill (direct precipitation from hydrothermal fluids into 'cavities'), alteration (the results of hydrothermal fluid reactions with wall rocks) and overprinting (the normal complexity caused by successive introduction of hydrothermal fluids usually accompanied or preceded by renewed fracturing) and ends with a detailed examination of textures associated with tectonic and intrusive breccias.
