Clumped isotope evidence for diachronous surface cooling of the Altiplano and pulsed surface uplift of the Central Andes

Spatially extensive paleoelevation records of the Altiplano plateau are critical to determining the geodynamic mechanisms that formed and support high elevations over a broad area. Prior stable isotope data reveal a climate history for the northern Bolivian Altiplano that has been interpreted to show rapid surface uplift of 2.5 ± 1.0km between ~10 and 6Ma. This study applies clumped isotope paleothermometry to paleosol carbonates formed at both a low-elevation site and temporally overlapping high-elevation sites in the southern Altiplano/Eastern Cordillera during the middle to late Miocene. Surface paleotemperature decreased by 14°C in the southern Altiplano/Eastern Cordillera relative to stable low-elevation paleotemperatures, implying surface elevation increase of 1.9 ± 0.7km between 16 and 13 Ma and an additional 0.7 ± 0.6km between 13 and 9 Ma. Both the large magnitude of surface temperature decrease and earlier onset (7 ± 4Myr) in the south as compared to the north suggest rapid elevation increase by piecemeal removal of lower lithosphere beneath the plateau and possible northward lower crustal flow.