Alpha-Recoil-Tracks (ART) - Formation and Cooling Ages
- Autores: U. A. Glasmacher, G.A. Wagner
- Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 4, 2002 (Ejemplar dedicado a: INTERNATIONAL WORKSHOP ON FISSION TRACK ANALISIS: THEORY AND APPLICATIONS), págs. 77-82
- Idioma: inglés
- Enlaces
-
Resumen
A new dating technique using alpha-recoil-tracks (ART) in dark mica, that are formed by the natural adisintegration ofU, Th, and their daughter products, allows to determine the formation age young volcanics as well as the cooling age during rock exhumation. The age equation combines the volume density (p) of ART with the U andTh contents. Etching latent ART (3 0 - 100 nm) inphlogopite by HFat various etching times and measuring the areal density o f triangular etch pits by optical or scanningforce microscopy (SFM) leads to a linear ART-growth (areal density versus etching time). The volume density of ART is derivedfrom the slope o f the ART-growth and the effective etch rate (veJf). With the ART method ages, ranging from 103 to 10s years, of tiny single grains can be determined. The potential o f ART-D for thermochronological applications is related to the low closure temperature around 60 C. Applying a constant geothermal gradient o f 30 C/km the exhumation of dark mica bearing rock below 2000 m is dated.
