Reverman,R.L., Fellin,M.G., Herman,F., Willett,S.D. and Fitoussi,C.(2012): Climatically versus tectonically forced erosion in the Alps: Thermochronometric constraints from the Adamello Complex, Southern Alps, Italy. Earth and Planetary Science Letters, 339-340, 127-138.

『アルプス山脈における気候誘引対構造誘引の浸食:イタリアの南アルプスのアダメロ岩体からの熱年代による制約』


Abstract
 We apply (U-Th-Sm)/He dating and fission-track thermochronometry of apatites to the Adamello Complex located in the southern European Alps. Our goal is to constrain exhumation rates since the Miocene, in particular, to determine whether the increase in sedimentation documented in the foreland basins since 5 Ma is recorded in cooling rates of the Southern Alps. Thermochronometry provides a cooling rate for rocks, which can be concerted to an exhumation rate through thermal modeling, thereby quantifying the amount of rock exhumed at different time scales. Apatite fission-track and (U-Th-Sm)/He analyses all record Miocene ages. We find no evidence for an increase in exhumation rate during the Plio-Pleistocene. The results of our exhumation rate estimates and tectono-geomorphic modeling suggest that unroofing during thrust propagation of the Southern Alps in the Late Miocene drove most of the exhumation, while changes in relief, mainly associated with Plio-Pleistocene climate change, likely did not affect the Adamello Complex. The findings from this study combined with other studies highlight that there appears to be a gradient across the Alps, with more intensive Plio-Pleistocene erosion in the Western and Central Alps compared to the Eastern and southern Alps.

Keywords: exhumation; Alps; helium; low-temperature thermochronology』

1. Introduction
2. Geologic setting
 2.1. Southern Alps
 2.2. The Adamello Complex
 2.3. Po Plain-Adriatic foredeep
3. Low-temperature thermochronometry
 3.1. Theory
 3.2. Method
 3.3. Thermochronometric results
  3.3.1. AFT
  3.3.2. (U-Th-Sm)/He ages
4. Quantitative interpretation: timing and rates of exhumation
 4.1. AER estimates
 4.2. Quantitative interpretation: numerical modeling
  4.2.1. Resolution tests
  4.2.2. Inversion parameterization
  4.2.3. Inversion results
5. Discussion
 5.1. Oligocene-Early Miocene exhumation?
 5.2. Late Miocene onset of exhumation
 5.3. Western vs. Eastern and Southern Alps
6. Conclusion
Acknowledgments
Appendix A. Supporting information
References


戻る