Andean surface uplift constrained by radiogenic isotopes of arc lavas.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29511197.
- Also identified by DOI 10.1038/s41467-018-03173-4 and PMC identifier 5840411.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Climate and tectonics have complex feedback systems which are difficult to resolve and remain controversial. Here we propose a new climate-independent approach to constrain regional Andean surface uplift. <sup>87</sup>Sr/<sup>86</sup>Sr and <sup>143</sup>Nd/<sup>144</sup>Nd ratios of Quaternary frontal-arc lavas from the Andean Plateau are distinctly crustal (>0.705 and <0.5125, respectively) compared to non-plateau arc lavas, which we identify as a plateau discriminant. Strong linear correlations exist between smoothed elevation and <sup>87</sup>Sr/<sup>86</sup>Sr (R<sup>2</sup> = 0.858, n = 17) and <sup>143</sup>Nd/<sup>144</sup>Nd (R<sup>2</sup> = 0.919, n = 16) ratios of non-plateau arc lavas. These relationships are used to constrain 200 Myr of surface uplift history for the Western Cordillera (present elevation 4200 ± 516 m). Between 16 and 26°S, Miocene to recent arc lavas have comparable isotopic signatures, which we infer indicates that current elevations were attained in the Western Cordillera from 23 Ma. From 23-10 Ma, surface uplift gradually propagated southwards by ~400 km.