| Autor: |
W. E. A. Phillips, D. W. Coller, A. Rowlands, A. Vaughan, J. Carter |
| Rok vydání: |
1988 |
| Předmět: |
|
| Zdroj: |
Mineral Deposits within the European Community ISBN: 9783642518607 |
| DOI: |
10.1007/978-3-642-51858-4_19 |
| Popis: |
The zinc-lead deposits of Silvermines and Navan are stratiform ore bodies hosted in carbonate sediments of lower Dinantian (Courceyan) age. These deposits overlie a Caledonian basement close to the Caledonian plate collision boundary. Geophysical data plus lithofacies structural, and remote sensing data from the Dinantian rocks of both regions indicate that granitic plutons of Caledonian age are situated close to both deposits. Detailed structural analyses in both mines and in their surrounding regions have shown that mineralization occurred in dilation zones which developed during minor dextral strike slip reactivation of Caledonian fractures. At Silvermines, E-W-trending dextral shear terminated to the east against the rigid obstruction of a buried Caledonian granite, thus generating a complex dilation zone of late Courceyan age. At Navan, NE-SW-trending dextral shear culminated in late Courceyan times with an eastward termination against Caledonian granitic and syenite intrusions. In both areas, the Caledonian granites may well have provided a source of heat which generated hydrothermal circulation of saline fluids. These models for the structural control of mineralization at Silvermines and Navan indicate that further exploration should be guided by methods which can identify Caledonian shear zones which have been reactivated during the Courceyan and which can identify where such shear zones terminate against buried Caledonian granitic plutons or volcanic complexes. Combinations of analyses of geophysical, structural, lithological and remote sensing data can be used for this purpose. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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