NA TURE 



245 



THURSDAY, JANUARY 10, 1901. 



THE SCIENCE OF ORE DEPOSITS. . 

 Lehre von den Erzlagerstdtten. By Dr. R. Beck. 

 I Theil. Pp. iv + 384. (Berlin: Borntraeger, 1901.) 



IN striking contrast to the almost universal neglect 

 with which the subject of ore deposits is treated in 

 this country is the increasing attention that it is receiv- 

 ing from geologists and mining engineers abroad, and 

 more especially in Germany and in the United States. In 

 the recently published annual general report and statistics 

 of the output of minerals in Great Britain, by Dr. C. Le 

 Neve Foster, attention is called to the fact that our pro- 

 duction of all metalliferous minerals, already small, is 

 continually shrinking, and whilst this unpleasant fact may 

 be the cause of the above-noted neglect of the study of ore 

 deposits, it may equally well be an effect thereof, and may 

 present one more example of the way in which we are 

 being left behind by other nations in industrial pursuits, 

 merely because we so uniformly disdain to study their 

 scientific aspects. 



The work now under review serves well to emphasise 

 the difference between the treatment of scientific techno- 

 logy in the two countries ; it is written by the professor 

 of geology and of the science of mineral deposits at the 

 ancient and famous Royal Mining School of Freiberg. 

 In this country we have no ancient mining schools — 

 perhaps even no mining schools at all, as the Germans 

 understand this term — and not a single professorship 

 devoted to the study of mineral deposits. 



This latter subject has nowhere been the subject of 

 more assiduous study than it has at Freiberg, and this fact 

 alone would make the present treatise one of exceptional 

 importance. Its author is, moreover, a recognised 

 authority on the theory of ore deposits, and his work is 

 marked with decided originality in many respects. The 

 only difficulty in forming a fair estimate of it lies in the 

 fact that the volume before us is only half a book, con- 

 cluding abruptly in the middle of a chapter. It seems 

 that the remainder is not to be published till next year, 

 and as the present part does not include any table of 

 contents it is impossible to say now what the scope of 

 the completed work will be. It is hard to see what good 

 end is to be served by this fragmental system of 

 publication. 



The most interesting point about any work on ore 

 deposits is the system of classification ^nd arrange- 

 ment adopted in it. Dr. Beck commences his work 

 by a division of all deposits into two main groups, 

 (i) Primary, and (2) Secondary, the latter group in- 

 cluding the deposits formed by the destruction of 

 pre-existing ones, whether as alluvial deposits or 

 by disintegration in situ. It is obvious that such a 

 division is defective in many respects, apart from the 

 fact that the two groups thus formed are of very unequal 

 importance. In the first place it is impossible in many 

 cases to predicate with certainty of an ancient deposit 

 that it was primary in its origin, seeing that all traces of 

 its original genesis may have been lost owing to wide- 

 reaching metamorphism ; and, again, there is no real 

 genetic difference between a recent mineral deposit and an 

 NO. 1628, VOL. 63] 



ancient one, and it is illogical to base the first great 

 classificatory grouping upon a distinction of such little 

 real importance. Worst of all, the author finds himself 

 unable to maintain his own classificatory system. A 

 striking example of this defect is his inclusion amongst the 

 primary deposits of " bedded gold deposits of Palccozoic 

 and Mesozoicage," the first example of which, given by him, 

 is certainly an alluvial deposit of Cambrian age, whilst all 

 the others were probably also alluvial deposits. Dr. 

 Beck's inclusion of Tertiary and more recent alluvial 

 deposits in his secondary group, whilst all alluvials older 

 than Tertiary are included among primary deposits, is 

 as arbitrary as it is unpractical, and, moreover, is in no 

 way justified by his own definitions. 



The group of primary deposits is here further divided 

 into {a) Syngenetic, or such as were formed contempor- 

 aneously with the surrounding rocks, and {b) Epigenetic, 

 or such as were formed subsequently ; the first class is 

 again subdivided into (i) Magmatic segregations, and (2) 

 Stratified ore deposits, and the second class into (i) Fissure 

 veins, and (2) Deposits that are not vein-like ; the latter 

 class is again further subdivided, but the deposits 

 included in it are not covered by the present volume, so 

 that their discussion must be deferred. Perhaps the least 

 satisfactory group of the present classification is the first 

 subclass of magmatic segregations, which is intended to 

 cover ore deposits produced by magmatic differentiation 

 from molten eruptive rocks. We doubt whether many 

 geologists would even endorse fully the opening sentence 

 of this section : " The origin of metals is, without doubt, 

 the inaccessible interior of the earth's crust," more 

 especially seeing that the main argument in support of 

 this very dogmatic statement is based upon the high 

 specific gravity of the earth as a whole, compared with 

 that of the rocks composing its surface. This subclass 

 is divided into three sections, namely, segregations of 

 native metals, of oxidised ores and of sulphuretted ores 

 respectively. The first section is especially unfortunate ; 

 the first examples quoted, namely, native iron in the 

 island of Disko, nickeliferous iron at Awarua, New 

 Zealand, and platinum in the Urals, are none of them 

 mineral deposits in the sense in which Dr. Beck, quite 

 correctly, defines the word, namely, deposits of mineral of 

 economic importance ; further, the last example, namely, 

 the occurrence of native copper in the melaphyres of Lake 

 Superior, is certainly not a case of magmatic segregation, 

 but is a well-marked instance of an epigenetic deposit ; 

 and the only other example, that of the occurrence of 

 gold in certain eruptive rocks, is in many cases neither 

 of economic importance nor of indisputably magmatic 

 origin. The next section, that of the oxidised ores, is 

 more satisfactory in many respects, although doubts 

 may well be entertained of the soundness of any 

 system of classification that separates, as widely as 

 Dr. Beck does, the iron ore deposits of Kirunavaara 

 and Luossavaara from those of Gellivaara and Svap- 

 pavaara, all four of which show very many and very 

 interesting points of similarity. The third section, 

 that of sulphuretted ores, is again open to doubt, and 

 it seems as though more stress had been laid upon the 

 accidental circumstance, whether a given deposit lies 

 wholly within or merely in proximity to an igneous out- 

 burst with which it is probably genetically connected, 



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