Low-temperature thermochronology in the Peruvian Central Andes: implications for long-term continental denudation, timing of plateau uplift, canyon incision and lithosphere dynamics
Gunnell, Y. and Thouret, J.C. and Brichau, S. and Carter, Andrew and Gallagher, K. (2010) Low-temperature thermochronology in the Peruvian Central Andes: implications for long-term continental denudation, timing of plateau uplift, canyon incision and lithosphere dynamics. Journal of the Geological Society 167 (4), pp. 803-815. ISSN 0016-7649.
In Peru, the western edge of the 4.5 km high Western Cordillera is cut by a>3 km deep canyon. To understand incision by the Cotahuasi-Ocona River and the regional uplift history of this orogenic plateau capped by volcanic rocks, 26 crystalline rock samples were collected for low-temperature thermochronology from vertical profiles parallel and perpendicular to the canyon. Rock cooling histories confirm that most plateau denudation had occurred prior to 24 Ma but plateau incision peaked after c. 14-9 Ma in response to rapid surface uplift. The abrupt occurrence of a rock heating event is also detected during middle Miocene time. This was either a response to the emplacement of low-conductivity, regionally extensive ignimbritic caprock or a response to crustal-scale fluid circulation caused by wet melting of the overriding plate when magmatism resumed c. 24 Ma. The potential for thermochronology to provide information on past geothermal gradients is discussed, showing how it can be used as a proxy for understanding change in subducting slab dynamics, with oscillations in subduction angle having perhaps been the main on-off switch for magmatism in this Cordilleran setting.
|School:||Birkbeck Schools and Departments > School of Science > Earth and Planetary Sciences|
|Date Deposited:||28 Feb 2011 15:02|
|Last Modified:||11 Oct 2016 11:55|
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