New U-Pb detrital zircon data of metasedimentary rocks of the Aguapeí Group, SW Amazonian Craton, are presented in this work. Three samples were analyzed by ICPMS laser ablation in order to estimate the age of the source areas of the sediments and the maximum depositional age of the basin. The samples show an Archean age of 2515. Ma not yet reported in the region. Paleoproterozoic ages of 2015. Ma, 1897. Ma and 1812. Ma were not reported in this area either, but are observed 1000-1200. km to NE, in the Rio Negro-Juruena province. The group of ages ranging from 1655. Ma to 1608. Ma may represent zircons from the Lomas Maneches orogen, described in Bolivia. The group of zircons with ages of 1544. Ma may be related to the Cachoeirinha (in Mato Grosso) or Serra da Providencia (in Rondonia) magmatic suite. The group of ages of ca 1485. Ma, 1417. Ma and 1411. Ma may represent zircons from the adjacent Santa Helena orogen, in Mato Grosso state. Data presented in this work suggest that the maximum depositional age for the Aguapeí sediments is 1.26. Ga, the youngest age among the detrital zircons analyzed. The U-Pb ages in zircon define important time constraint for the Aguapei Group sedimentary rocks deposition. In addition, the results here reported define new challenges in order to identify rocks not yet found in the region that may result in a more complete framework for SW Amazonian Craton crustal evolution.
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Vargas-Matos thanks CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil) for the financial support. Camila Nogueira, Wilson Teixeira and Mauro C. Geraldes greatly acknowledge the support of CNPq. The criticism by the reviewers was gratefully appreciated, and considered very important for the final version of this paper.