The deposits of the useful minerals & rocks; their origin, form, and content . uence in age is often as follows : after a first generation ofquartz follow most of the sulphides, including the greater portion of theargentite ; with these sulpliides the older calcite is approximately con-temporaneous ; then come fluorite and adularia, albite and barite, anddifferent carbonates ; and finally the zeolites, the pyrite, and the youngest 1 Poggendorfs Ann. 60, 1843. 2 Ajite, p. 131. * Hofer, Erdolstudien, Wiener Akad. Verh., 1902. THE LEAD-SILVEE-ZINC LODES 663 calcite generation. The argentite and i
The deposits of the useful minerals & rocks; their origin, form, and content . uence in age is often as follows : after a first generation ofquartz follow most of the sulphides, including the greater portion of theargentite ; with these sulpliides the older calcite is approximately con-temporaneous ; then come fluorite and adularia, albite and barite, anddifferent carbonates ; and finally the zeolites, the pyrite, and the youngest 1 Poggendorfs Ann. 60, 1843. 2 Ajite, p. 131. * Hofer, Erdolstudien, Wiener Akad. Verh., 1902. THE LEAD-SILVEE-ZINC LODES 663 calcite generation. The argentite and its alteration to native silverbelong to one of the early phases of formation. The lodes at Kongsberg are generally of httle width, this dimensionusually varying from the thickness of paper up to 10 cm., and butseldom reaching more than 33 cm. The strike is mostly west-south-westor approximately at right angles to that of the crystalline schists ; oftenseveral parallel lodes or veins are bunched together. A few, knownlocally as bedded lodes, agree in strike with the Garnet-biotite schist. Fig. 331.—Longitudinal section of the richest portion of the Kongens mine,between 320 and 520 m. in depth. C. Bugge. The rocks, represented as in Fig. 330, are from foot-wall to hanging-wall: aniphibolite, sericite-schist,garnet-biotite schist, and fine-grained foliated granite, the last three alternating in certain zones with pyriteimpregnations and amphibolite ; foliated granite in the hanging-wall. The areas indicated as having beensloped represent the argentiferous portions of the lode plane. Concerning the distribution of the silver, the experience of more thana century shows that this is exclusively or almost exclusively confined tothose areas on the lode plane where, as illustrated in Fig. 331, that planeintercepts the fahlbands, or in the case of the bedded lodes where suchfollow the fahlbands. Where the lodes, leaving the fahlbands, continueinto the adjacent rock free from
Size: 1766px × 1414px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectminesandmineralresou
