The deposits of the useful minerals & rocks; their origin, form, and content . Fig. 332.—MajD of the Freiberg lode district, neighbourhood of Freiberg. zone. Resting on this inner zone comes the outer contact zone of quartz- 672 ORE-DEPOSITS and albite-phyllites, these towards the hanging-wall merging into micaceous. Quartz-silver ^iij iihiie Bante *j lodes lead-copper iead-si/ver lodes lodei Iron manganeie Silver-lead and Lamprophyrelodes Dclamitelsad lodes Fig. 333.—Map of the Freiberg lode district, neighbourliood of Brand. phyllite. Finally, come the unaltered rocks, which are but sHghtly
The deposits of the useful minerals & rocks; their origin, form, and content . Fig. 332.—MajD of the Freiberg lode district, neighbourhood of Freiberg. zone. Resting on this inner zone comes the outer contact zone of quartz- 672 ORE-DEPOSITS and albite-phyllites, these towards the hanging-wall merging into micaceous. Quartz-silver ^iij iihiie Bante *j lodes lead-copper iead-si/ver lodes lodei Iron manganeie Silver-lead and Lamprophyrelodes Dclamitelsad lodes Fig. 333.—Map of the Freiberg lode district, neighbourliood of Brand. phyllite. Finally, come the unaltered rocks, which are but sHghtly meta- THE LEAD-SILVEE-ZINC LODES 673 morphosed in their bottom layers. These last, according to fossil evidence,belong to the Cambrian. The Freiberg lodes represent fissure-fiUings, most of which dip steeply,and along which the country-rock is more or less highly altered. It wasfrom this district that the scientific investigation of ore-deposits first pro-ceeded. Here Werner formulated his lode theories, and here also the exist-ence of lode-groups in individual districts was first recognized, these groupsbeing based upon difference in geological age, strike, and filling. Such localclassification as this, though doubtless apt in the case of Freiberg, hasunfortunately become too generahzed. Though groups base
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectminesandmineralresou
