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Gold deposits: origin, evolution, and present characteristics
92
area, and between continents. World and regional organizations of nations, professional groups, and private interests are increasingly dealing with the problems of feeding and clothing a growing world population; of diversifying and bolstering the economics of developing nations; and of educating and training national populations to be self-sustaining. Availability of water resources and the options for development for various purposes frequently are major constraints on the physical alternatives for addressing these problems. In this context, this reference, and expanded works of this type, are essential in establishing priorities for public and private investments. The following specific suggestions for improving "he ready usability of the data included in this compilation are made for the purpose both of highlighting some weaknesses in the compilation, and to assist in further efforts to expand the work: (1) A map of each nation and continental area should precede the tabulations of data for that area, with reported major river systems and municipal or other water users identified. This would make it possible for the user to relate geographic proximity of problems and development potential. (2) The data should all be presented in metric units for ease of comparison. H.O. Banks, Belmont, Calif.
GOLD DEPOSITS J.H. Tatsch, 1975. Gold Deposits: Origin,
Evolution,
and
Present
Characteristics.
Tatsch Associates, Sudbury, Mass., 275 pp,, U.S. $ 72.00. This book, constituting of 12 chapters, references, and an index, purports to be an analysis of the present gold deposits in terms of the geometrical, mechanical, thermal, and chemical aspects of the Earth's behaviour during the past 4--6 billion years. The first chapter is a sketchy global survey of the gold deposits of the world. It is stated that for the purpose of the book the gold deposits are classified in terms of volcanogenic environments, ten types being categorized. There is no doubt that some
types of gold deposits occur in volcanic belts, but many gold deposits (e.g., those in greywacke--slate sequences and in quartz-pebble conglomerates) seem quite unrelated to volcanogenic processes. In fact the great deposits of the Witwatersrand (which produce some 55% of the present world production of gold) have been omitted from the Tatsch classification in this chapter altogether. Modern gold placers are, likewise, omitted. No classification of gold deposits is satisfactory which does not take into account the remarkable quartz--pebble conglomerate deposits of gold (and uranium, thorium, and rare earths). The next four chapters deal with the Tectonospheric earth model conceived by Tatsch to explain both the internal and external features of the earth, mineral deposits, and other phenomena. This model postulates that the earth is fragmented into octants along fractures up which the inner material has moved to be deposited at the surface. Mixed up with the concept of the model are expositions on plate tectonics, omniductive processes, seismotectonomagmatic (orogenic) belts, intrusive and extrusive activity, and metallogenesis. Like all attempts to explain ore deposits in terms of the fundamental processes of the earth, Tatsch's theory is highly speculative, obscure, and lacks a basis of facts in the opinion of this reviewer. In the next five chapters Tatsch gives descriptions of some of the gold deposits of the different geological e ra s (Cenozoic, Mesozoic, Paleozoic, Proterozoic, and Archean). Some of the descriptions are adequate although brief; others leave much to be desired. For instance (p. 87) the hot springs of New Zealand are said to contain 85 ppm gold and 500 ppm silver. This gives the impression that the waters contain this metallic content whereas it is the precipitate that is auriferous. Also, on p. 98, the famous Homestake mine in South Dakota is likened to Cripple Creek in Colorado. I doubt if few geologists would agree with this conclusion. More on this reviewer's home ground are descriptions of Canadian gold deposits. As is well known nearly all of the productive gold deposits in the Canadian Shield are of Archean age; only a very few (none of the authentic ones are mentioned
93 by Tatsch} are of Proterozoic age. Yet Tatsch has the Gunnar deposit in Manitoba (p. 150) in a Paleozoic seismotectonomagmatic belt. A number of deposits (e.g., Bankfield, Cadillac, Leitch, Little Long Lac, Matachewan, Siscoe, Rouyn, and so on) are said to be in Proterozoic seismotectonomagmatic belts. Even more startling is the statement about the Canadian Shield (p. 170) that "There is a very little placer gold, probably because there has been practically no seismotectonomagmatic-belt activity in the region during the Proterozoic and Phanerozoic". This is certainly contrary to the generally accepted view that extensive glaciation has removed and dispersed the gold placers which were probably formed during Tertiaty and earlier times. In the chapter on Archean deposits Tatsch has the Kirkland Lake and Larder Lake deposits in Quebec whereas both are in Ontario. Even harder to take by this reviewer is the statement that " t h e origin of the Yellowknife deposits resembles the origin of those at Witwatersrand". In the last t w o chapters in his book Tatsch invokes his tectonospheric model to explain the present distribution of gold deposits and attempts to apply it as an exploration tool. Chapter 11 contains another classification of gold deposits different f r o m that in Chapter 1. In this chapter fossil placers are mentioned, but the Witwatersrand and similar deposits receive only a three line treatment. In the last chapter (4 pp.) the statements made with respect to exploration for gold deposits are so general and obscure as to be of relatively little value to anyone prospecting for the precious metal. The editing of the book is poor as witnessed by an incredible number of typographical errors and misspelled mineral and place names. R.W. Boyle, Ottawa, Ont.
ORE DEPOSITS C.F. Park and R.A. MacDiarmid, 1975. Ore Deposits. 3rd ed. W.H. Freeman, San Francisco, 529 pp., ~ 9.70. Book reviews can reveal more about the
attitude and background o f the reviewer than the w o r k being reviewed. This danger is more than usually d i f f i c u l t to avoid in reviewing the third edition of Ore Deposits after having frequently consulted parts of the first and second editions over a period of more than ten years. Moreover, the main content of the book is already well known to most economic geologists. Ore Deposits, as stated in the preface to the third edition, " . . . presents to the beginning student of economic geology the principles and data basic to understanding the genesis and localization of the metallic ores and non-metallic minerals associated with t h e m " - - i . e . , it is intended to be an introductory text. In this c o n t e x t it provides a classical dissertation in the first six chapters on historal background, the nature of orebearing fluids, migration of ore fluids, deposition of ores, alteration, and paragenesis and zoning. Chapter 7 - - o n geothermometry and isotopic methods of studying conditions of ore deposition -- has been considerably revised. Niggli's, Schneiderhohn's, and Lindgren's classification systems of ore deposits are reviewed in Chapter 8. The descriptions of ore deposits that f o l l o w in Chapters 9--20 essentially conform to the basic Lindgren scheme: magmatic segregations, pegmatites, igneous metamorphic deposits, hypthermal, mesothermal, epithermal, telethermat, zenothermal, volcanogenic, sedimentary, weathering, and supergene enrichment. The final t w o chapters (21 and 22) on metamorphism of ores and metallogenic provinces and epochs are brief (7 pp. and 6 pp., respectively), and do little more than introduce the subjects; plate tectonics, in particular, receives only a cursory treatment. The third edition, despite the up-dating of concepts and references and the addition of a chapter on volcanogenic deposits (my frustration at no mention of the Cyprus examples is perhaps an indication of my interests and bias) remains a disapppointment as a t e x t on economic geology. Part of the problem is, of course, that what constitutes economic geology is very much in the "eye of the beholder' - a n d I expect economic geology to be filled with the excitement of the past discovery history and the anticipation of future discoveries. However,
area, and between continents. World and regional organizations of nations, professional groups, and private interests are increasingly dealing with the problems of feeding and clothing a growing world population; of diversifying and bolstering the economics of developing nations; and of educating and training national populations to be self-sustaining. Availability of water resources and the options for development for various purposes frequently are major constraints on the physical alternatives for addressing these problems. In this context, this reference, and expanded works of this type, are essential in establishing priorities for public and private investments. The following specific suggestions for improving "he ready usability of the data included in this compilation are made for the purpose both of highlighting some weaknesses in the compilation, and to assist in further efforts to expand the work: (1) A map of each nation and continental area should precede the tabulations of data for that area, with reported major river systems and municipal or other water users identified. This would make it possible for the user to relate geographic proximity of problems and development potential. (2) The data should all be presented in metric units for ease of comparison. H.O. Banks, Belmont, Calif.
GOLD DEPOSITS J.H. Tatsch, 1975. Gold Deposits: Origin,
Evolution,
and
Present
Characteristics.
Tatsch Associates, Sudbury, Mass., 275 pp,, U.S. $ 72.00. This book, constituting of 12 chapters, references, and an index, purports to be an analysis of the present gold deposits in terms of the geometrical, mechanical, thermal, and chemical aspects of the Earth's behaviour during the past 4--6 billion years. The first chapter is a sketchy global survey of the gold deposits of the world. It is stated that for the purpose of the book the gold deposits are classified in terms of volcanogenic environments, ten types being categorized. There is no doubt that some
types of gold deposits occur in volcanic belts, but many gold deposits (e.g., those in greywacke--slate sequences and in quartz-pebble conglomerates) seem quite unrelated to volcanogenic processes. In fact the great deposits of the Witwatersrand (which produce some 55% of the present world production of gold) have been omitted from the Tatsch classification in this chapter altogether. Modern gold placers are, likewise, omitted. No classification of gold deposits is satisfactory which does not take into account the remarkable quartz--pebble conglomerate deposits of gold (and uranium, thorium, and rare earths). The next four chapters deal with the Tectonospheric earth model conceived by Tatsch to explain both the internal and external features of the earth, mineral deposits, and other phenomena. This model postulates that the earth is fragmented into octants along fractures up which the inner material has moved to be deposited at the surface. Mixed up with the concept of the model are expositions on plate tectonics, omniductive processes, seismotectonomagmatic (orogenic) belts, intrusive and extrusive activity, and metallogenesis. Like all attempts to explain ore deposits in terms of the fundamental processes of the earth, Tatsch's theory is highly speculative, obscure, and lacks a basis of facts in the opinion of this reviewer. In the next five chapters Tatsch gives descriptions of some of the gold deposits of the different geological e ra s (Cenozoic, Mesozoic, Paleozoic, Proterozoic, and Archean). Some of the descriptions are adequate although brief; others leave much to be desired. For instance (p. 87) the hot springs of New Zealand are said to contain 85 ppm gold and 500 ppm silver. This gives the impression that the waters contain this metallic content whereas it is the precipitate that is auriferous. Also, on p. 98, the famous Homestake mine in South Dakota is likened to Cripple Creek in Colorado. I doubt if few geologists would agree with this conclusion. More on this reviewer's home ground are descriptions of Canadian gold deposits. As is well known nearly all of the productive gold deposits in the Canadian Shield are of Archean age; only a very few (none of the authentic ones are mentioned
93 by Tatsch} are of Proterozoic age. Yet Tatsch has the Gunnar deposit in Manitoba (p. 150) in a Paleozoic seismotectonomagmatic belt. A number of deposits (e.g., Bankfield, Cadillac, Leitch, Little Long Lac, Matachewan, Siscoe, Rouyn, and so on) are said to be in Proterozoic seismotectonomagmatic belts. Even more startling is the statement about the Canadian Shield (p. 170) that "There is a very little placer gold, probably because there has been practically no seismotectonomagmatic-belt activity in the region during the Proterozoic and Phanerozoic". This is certainly contrary to the generally accepted view that extensive glaciation has removed and dispersed the gold placers which were probably formed during Tertiaty and earlier times. In the chapter on Archean deposits Tatsch has the Kirkland Lake and Larder Lake deposits in Quebec whereas both are in Ontario. Even harder to take by this reviewer is the statement that " t h e origin of the Yellowknife deposits resembles the origin of those at Witwatersrand". In the last t w o chapters in his book Tatsch invokes his tectonospheric model to explain the present distribution of gold deposits and attempts to apply it as an exploration tool. Chapter 11 contains another classification of gold deposits different f r o m that in Chapter 1. In this chapter fossil placers are mentioned, but the Witwatersrand and similar deposits receive only a three line treatment. In the last chapter (4 pp.) the statements made with respect to exploration for gold deposits are so general and obscure as to be of relatively little value to anyone prospecting for the precious metal. The editing of the book is poor as witnessed by an incredible number of typographical errors and misspelled mineral and place names. R.W. Boyle, Ottawa, Ont.
ORE DEPOSITS C.F. Park and R.A. MacDiarmid, 1975. Ore Deposits. 3rd ed. W.H. Freeman, San Francisco, 529 pp., ~ 9.70. Book reviews can reveal more about the
attitude and background o f the reviewer than the w o r k being reviewed. This danger is more than usually d i f f i c u l t to avoid in reviewing the third edition of Ore Deposits after having frequently consulted parts of the first and second editions over a period of more than ten years. Moreover, the main content of the book is already well known to most economic geologists. Ore Deposits, as stated in the preface to the third edition, " . . . presents to the beginning student of economic geology the principles and data basic to understanding the genesis and localization of the metallic ores and non-metallic minerals associated with t h e m " - - i . e . , it is intended to be an introductory text. In this c o n t e x t it provides a classical dissertation in the first six chapters on historal background, the nature of orebearing fluids, migration of ore fluids, deposition of ores, alteration, and paragenesis and zoning. Chapter 7 - - o n geothermometry and isotopic methods of studying conditions of ore deposition -- has been considerably revised. Niggli's, Schneiderhohn's, and Lindgren's classification systems of ore deposits are reviewed in Chapter 8. The descriptions of ore deposits that f o l l o w in Chapters 9--20 essentially conform to the basic Lindgren scheme: magmatic segregations, pegmatites, igneous metamorphic deposits, hypthermal, mesothermal, epithermal, telethermat, zenothermal, volcanogenic, sedimentary, weathering, and supergene enrichment. The final t w o chapters (21 and 22) on metamorphism of ores and metallogenic provinces and epochs are brief (7 pp. and 6 pp., respectively), and do little more than introduce the subjects; plate tectonics, in particular, receives only a cursory treatment. The third edition, despite the up-dating of concepts and references and the addition of a chapter on volcanogenic deposits (my frustration at no mention of the Cyprus examples is perhaps an indication of my interests and bias) remains a disapppointment as a t e x t on economic geology. Part of the problem is, of course, that what constitutes economic geology is very much in the "eye of the beholder' - a n d I expect economic geology to be filled with the excitement of the past discovery history and the anticipation of future discoveries. However,