Open AccessLead isotope signatures of mineralised rocks in the Caledonian fold belt of North-East Greenland
Author(s) -
S.M Jensen
Publication year - 1994
Publication title -
rapport
Language(s) - English
Resource type - Journals
eISSN - 2597-2944
pISSN - 0418-6559
DOI - 10.34194/rapggu.v162.8259
Subject(s) - geology , proterozoic , geochemistry , skarn , precambrian , gneiss , breccia , pyrite , fold (higher order function) , isotope geochemistry , pegmatite , shear zone , quartz , metamorphic rock , paleontology , isotope , fluid inclusions , tectonics , mechanical engineering , physics , quantum mechanics , engineering
Lead isotope analyses of samples with small accumulations of metals and incompatible elements from the Precambrian gneisses of North-East Greenland indicate that mineralisation mostly involved remobilisation of metals from local host rocks. Source ages of Iead fall in three groups: (I) 1700–2400 Ma for Lower Proterozoic skarns, Caledonian sulphide-bearing pegmatites and quartz veins, and post-Jurassic pyrite-mineralised fault breccias; (2) 900–1000 Ma for Caledonian shear zones and Caledonian(?) skarns in Middle-Late Proterozoic rocks; and (3) ~400 Ma for Caledonian thrust zones with associated relative uranium enrichment along thrust planes.