An enigmatic profile from a 3440 m deep drill hole in the southern Canadian Shield: results from apatite fission track and (U -Th)/H e thermochronometry

• Autores: M. Lorencak, Barry P. Kohn, K.G. Osadetz, Andrew J.W. Gleadow
• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 4, 2002 (Ejemplar dedicado a: INTERNATIONAL WORKSHOP ON FISSION TRACK ANALISIS: THEORY AND APPLICATIONS), págs. 117-118
• Idioma: inglés
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• Resumen

  • A 3440 m deep borehole at Sudbwy, in the southern Canadian Shield has been investigated using a combination ofapatite fission track (AFT) and (U-Th)/He thermochronometry as part of a major regional thermochronological study of the Canadian Shield. 19 samples were collected downhole at ~200 m intervals. Apparent AFT ages range from -360 Ma at the surface to -140 Ma at the base. Chemical composition of apatite ranges from 0.1 to 2 wt% Cl. Preliminaiy apatite (U-Th) He results yield ages o f-250 Ma at the surface and decrease towards 0 Ma at -3000 m, at a present day bottom hole temperature o f -65 °C. The age-depth projile reveals a sinuous form with an amplitude of-W 0 m.y. for the AFT ages. The projile form is also independently rejlected in the (U-Th) He data. A preliminary interpretation o f the projile pattern indicates that it did not result J'rom tectonic offsets, but is possibly related to hot Jluidjlow or chemical composition affects or a combination of both.