Contradicting apatite fission track and (U-Th)/He data from the Precam brian basem ent in Sweden: How accurate are the thermochronology methods for slowly cooled samples?

• Autores: C. Ceberdom, Finlay M. Stuart, M. Naylor
• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 4, 2002 (Ejemplar dedicado a: INTERNATIONAL WORKSHOP ON FISSION TRACK ANALISIS: THEORY AND APPLICATIONS), págs. 47-48
• Idioma: inglés
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• Resumen

  • The Swedish part o f the Baltic Shield is characterized by a Precambrian basement, and a few remnants o f Phanerozoic cover rocks. Apatite fission track (FT) analyses o f outcrop and borehole samples from the Precambrian basement have revealed that central and southern Sweden experienced heating due to burial beneath thick, extensive foreland basin deposits during the Late Palaeozoic (Cederbom et al„ 2000; Larson et al., 1999). Furthermore, three areas with different trends among the FT results have been discerned in southern Sweden, suggesting differential exhumation during the Early Mesozoic (Cederbom, 2001). The geological development during the Cretaceous and onwards has been more difficult to verify. Mesozoic sedimentary remnants, deposited directly on basement, demonstrate that the south Swedish coasts were exposed before Late Cretaceous sedimentation started. When using this as a constraint, modelling o f the apatite FT data indicate that the south Swedish coasts were reheated due to burial beneath CretaceousPaleogene deposits before Neogene final exhumation started (Cederbom, in press,). By performing (U-Th)/He measurements on some o f the apatite samples from southern Sweden we aimed to constrain the amount reheating during the Cretaceous-Palaeogene.