『Abstract
Studies of active mountain ranges suggest that atmospheric and
geodynamic processes may be strongly coupled through erosion -
a hypothesis that has led to a debate over the relative importance
of climate and far-field tectonic forcing in influencing erosion.
We addressed this debate by developing the detailed long-term
erosional history of a transect in the central Annapurna Range
of Nepal for comparison with the climate and tectonic forcing
histories of the region. Patterns of apatite fission-track and
muscovite 40Ar/39Ar apparent ages with elevation
indicate a five-fold increase in apparent erosion rate between
2.5 and 0.9 Ma ago. The time frame for this change corresponds
to that of global climate destabilization associated with the
onset of Northern Hemisphere glaciation and an intensification
of the Asian monsoon. There is no evidence for important changes
in the far-field tectonics of the Himalayan-Tibetan orogenic system
over that interval, suggesting a largely climatic driver for enhanced
erosion at the Himalayan range front.
Keywords: Himalaya; erosion; climate; fission-track geochronology;
Argon geochronology』
1. Introduction
2. Approach and geologic setting
3. Fission-track analytical methods
4. Results and interpretations
5. Corroborating evidence for a 2.5-0.9 Ma change in erosion rate
in the central Himalaya
6. Arguments in favor of climate change as the cause of accelerated
erosion
7. Evidence for late-stage slip near the trace of the Main Central
thrust
8. Discussion and conclusions
Acknowledgements
Appendix A. Statistical comparison of apatite fission-track and
muscovite 40Ar/39Ar age-elevation gradients
Appendix B. Thermal model details
References
References cited in Appendix B