Constraints on the age and genesis of the Llanrwst and Llanfair-Talhaiarn orefields, North Wales from K-Ar and Rb-Sr studies

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Authors:Haggerty, R.; Bottrell, S. H.; Cliff, R. A.; Rex, D. C.
Author Affiliations:Primary:
University of Leeds, Department of Earth Sciences, Leeds, United Kingdom
Volume Title:Geological Magazine
Source:Geological Magazine, 132(4), p.387-398. Publisher: Cambridge University Press, London, United Kingdom. ISSN: 0016-7568
Publication Date:1995
Note:In English. 26 refs.; illus., incl. 6 tables, geol. sketch map
Summary:Dating of sericitized wallrock indicates that the main phase of mineralization at both orefields occurred between mid-Devonian and the Tournaisian (386-350 m.y.). Gangue Sr isotope compositions indicate a mixture of radiogenic wallrock-derived Sr and less radiogenic Sr, with a poorly defined trend to more radiogenic compositions with time. The age of the main mineralization precludes dewatering of Carboniferous basins as a source of ore fluid. More generally Sr isotopes rule out unmodified basinal brines and metamorphic fluids as mineralizing agents, since their Sr contents would be too radiogenic. Local sources of unradiogenic Sr are available to Llanrwst in metadolerites and calcareous sandstones and at Llanfair-Talhaiarn in thin Ludlow Limestone beds. [C.H.D.]
Subjects:Absolute age; Alkaline earth metals; Dates; Fluid inclusions; Inclusions; Isotopes; K/Ar; Lead-zinc deposits; Lower Paleozoic; Ludlow; Metal ores; Metals; Mineral deposits, genesis; Ore-forming fluids; Paleozoic; Rb/Sr; Silurian; Sr-87/Sr-86; Stable isotopes; Strontium; Upper Silurian; Llanfair-Talhaiarn orefields; Llanrwst orefields; Northern Wales
Abstract Numbers:96M/13
Record ID:1996008653
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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