Michalak M. J., Hall S. R., Farber D. L., Audin Laurence, Hourigan J. K. (2016). (U-Th)/He thermochronology records late Miocene accelerated cooling in the north-central Peruvian Andes. Lithosphere, 8 (2), p. 103-115. ISSN 1941-8264.
Titre du document
(U-Th)/He thermochronology records late Miocene accelerated cooling in the north-central Peruvian Andes
Michalak M. J., Hall S. R., Farber D. L., Audin Laurence, Hourigan J. K.
Source
Lithosphere, 2016,
8 (2), p. 103-115 ISSN 1941-8264
The along-strike morphology of the South American Andes varies significantly, but it remains unclear if the timing and magnitude of rock exhumation are similarly varied. We used low-temperature (U-Th)/He thermochronology to constrain the exhumation history of the Eastern Cordillera in the north-central Peruvian Andes (7 degrees S-8.5 degrees S). Nine zircon (U-Th)/He mean ages range from 28 +/- 4.5 Ma to 281 +/- 60 Ma, and seven apatite (U-Th)/He mean ages yield tightly clustered late Miocene ages of 6.4 +/- 3.8 Ma to 10.7 +/- 1.8 Ma. These results document slow rock cooling followed by abrupt, accelerated cooling in the mid-late Miocene. Model time-temperature histories show slow cooling throughout the late Paleozoic to early Miocene, followed by an increase in cooling initiating between 14 and 10 Ma and continuing to the present. This rock cooling signal is regionally synchronous along the strike of the range and occurs at a time of a shift to a more humid and erosive climate in the eastern Andes. We suggest that a mid-late Miocene climate shift, following or synchronous with topographic growth, was responsible for the acceleration of rock exhumation in the north-central Peruvian Andes.
Plan de classement
Sciences du milieu [021]
;
Géologie et formations superficielles [064]
