40Ar/39Ar Thermochronology of Late‐ and Postorogenic Extension in the Caledonides of North‐Central Norway
| Autor: | Brad T. Carter, Mark G. Steltenpohl, Arild Andresen, Daniel L. Zeltner |
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| Rok vydání: | 2009 |
| Předmět: | |
| Zdroj: | The Journal of Geology. 117:399-414 |
| ISSN: | 1537-5269 0022-1376 |
| DOI: | 10.1086/599217 |
| Popis: | We report 40Ar/39Ar mineral cooling data that elucidate the timing and style of Devonian late‐orogenic extensional collapse and Permian‐Triassic postorogenic continental rifting in the north‐central Norwegian Caledonides. 40Ar/39Ar mineral cooling ages from ductile extensional shear zones that have either excised or reactivated Caledonian thrust faults along the western flanks of two major basement domes indicate that late‐orogenic extensional deformation in this region occurred during the Early (ca. 409–388 Ma) and Late Devonian (ca. 371–355 Ma). These extensional pulses are consistent with events recently identified by workers investigating areas to the south of our study area. The timing and style of the Early Devonian event supports the northern continuation of the Devonian orogen‐parallel, scoop‐shaped extensional deformation documented in the central Norwegian Caledonides. Late Devonian extension, on the other hand, was orogen‐orthogonal. This Late Devonian event is similar in timing and ki... |
| Databáze: | OpenAIRE |
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