LEAD ISOTOPE AND PB-PB MODEL AGE-DETERMINATIONS OF ORES FROM CENTRAL-EUROPE AND THEIR METALLOGENETIC INTERPRETATION

被引:51
作者
BIELICKI, KH [1 ]
TISCHENDORF, G [1 ]
机构
[1] CENT INST PHYS EARTH,W-1561 POTSDAM,GERMANY
关键词
D O I
10.1007/BF00321987
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
The paper presents lead isotope data from 211 samples from Phanerozoic lead-bearing ore occurrences in Central Europe, particularly from the Southern part of the former German Democratic Republic. The data are interpreted in terms of Amov's dynamic model of continuous lead isotope evolution. The relationships between thoro-genic and urano-genic model ages and the source of lead in different regional units are discussed. We observed differences in lead isotope evolution in the Hercynian internides and externides. Within the Moldanubian and Saxothuringian zones we distinguish five main lead-bearing ore associations: (1) Cambrian, stratiform base metal (Hermsdorf - Waldsassen; Pb-206/Pb-204 = 17.50-17.70), (2) Devonian, vein type Sb-bearing, metamorphogene (Neumuhle - Hartmannsdorf; 17.80-18.00), (3) Upper Carboniferous-Permian, polymetallic, including tin, vein type (Kutna hora - Freiberg-Altenberg; 18.00-18.20), (4) Triassic (-Jurassic), Pb - Ba, vein type (Stribro - Halsbrucke; 18.20-18.60), (5) Cenozoic, polymetallic, vein type, riftogene (Roztoky - Banska Stiavnica; 18.80-19.10). Pb isotope characteristics from ores of the Montagne Noire and the Brioude-Massiac district correspond to this subdivision. Ore associations from the Rheno-Hercynian zone display higher Pb-207/Pb-204 ratios which can be explained by more evolved and less metamorphosed source rocks. Mineralizations of the eastern Harz (Stra-beta-berg - Neudorf) belong to the Permian association, those from the western Harz (Clausthal - Bad Grund) to the Triassic-Jurassic. Because of Pb isotope agreement the stratabound Rammelsberg and the vein bound Ramsbeck-I mineralization are presumed to be isogenetic. Pb isotope identity of distinct mineralizations in the basement zone (Halsbrucke - Bad Grund) and in the Triassic sediments (Gorny Slask-Mechernich - Bleiglanzbanke) suggests a strong genetic coherence. Pb isotope conformity between the Upper Carboniferous-Permian-Triassic ore associations and Hercynian postkinematic granitoids, and lamprophyric rocks, also favours a close relationship. Pb isotope and other data indicate crustal sources. As the age of the ore associations decreases, crustal influences generally increase, apart from the Roztoky mineralization.
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页码:440 / 461
页数:22
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