Abstract

Detrital thermochronology is commonly used to locate source and improve the understanding of a region's long-term development. Provenance detrital age data typically comprise a number of distinct age modes representing contributions from a number of different sources. For methods such as apatite fission track (FT) this can present a challenge in that direct assignment of age modes to particular lithological or tectono-stratigraphic units is rarely possible, particularly when ancient orogenic sediments are examined. A new approach described here is based on measuring Nd isotopic data on single apatites by laser ablation ICPMS where the ¹⁴³Nd/¹⁴⁴Nd ratios are diagnostic of grain source. By combining Nd isotopic measurement with apatite FT analysis it is possible to link detrital apatite FT ages to specific rock unit sources. The methodology and wider benefits of this new approach are discussed using examples from the Himalaya and Andaman Islands.