Present status and future avenues of source region discrimination and characterization using fission track analysis

Abstract

Amongst the various dating methods available for use in sediment provenance studies there exists a wide range (∼60–900°C) of temperature stability fields that can be used to record different geological processes. The adoption of a particular geochronological method for use in the study of provenance requires selecting a technique and mineral phase that have a thermal stability range suited to the type of provenance information required. This paper describes the unique provenance applications of the low temperature (∼60–320°C) fission track (FT) method. Apatite fission track data can monitor changes in the thermal regime of the upper 3–5 km of crust and are therefore particularly sensitive to cycles of burial, tectonic and erosive denudation. Provenance applications include dating source, estimating source denudation rates, detecting changes in tectonic processes, constraining models of thermal evolution at the depositional site and reconstructing eroded sections. Future detrital apatite FT applications should concentrate on improving resolution of the temporal relationships between source evolution and sedimentation in adjacent basins. A small study from the Hebrides Basin, western Scotland is used to demonstrate the effectiveness of adopting such an approach. The range of applications for detrital zircon FT data is more restricted due primarily to difficulties interpreting a detrital zircon age because of possible metamorphic resetting. Common applications that avoid these uncertainties include dating source, determination of source denudation rates and constraining the age of biostratigraphically barren sediments. In the future, interpretative difficulties may be overcome by adopting a dual approach to zircon dating using both U–Pb and FT methods.