U–Pb detrital zircon ages from the Aguapeí Group (Brazil): Implications for the geological evolution of the SW border of the Amazonian Craton
U–Pb detrital zircon ages from the Aguapeí Group (Brazil): Implications for the geological evolution of the SW border of the Amazonian Craton
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DOI：
10.1016/j.precamres.2014.02.001
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发表时间：
2014-05
影响因子：
3.8
通讯作者：
M. Geraldes;C. C. Nogueira-C.;Gabriela Vargas-Mattos;Ramiro Matos;W. Teixeira;V. Valencia;J. Ruíz
中科院分区：
文献类型：
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作者：
M. Geraldes;C. C. Nogueira-C.;Gabriela Vargas-Mattos;Ramiro Matos;W. Teixeira;V. Valencia;J. Ruíz
本文报道了西南亚马逊河克拉通Aguapeí群变质沉积岩中新的U-Pb碎屑锆石资料。利用ICPMS激光烧蚀法对3个样品进行了分析，以估计沉积物源区的年龄和盆地的最大沉积年龄。样品显示该地区尚未报道的太古宙年龄为2515 Ma。2015 Ma、1897 Ma和1812 Ma的古元古代年龄在该地区也没有报道，但在内格罗-朱鲁埃纳省里约热内卢向北1000-1200 km处观测到。年龄在1655 ~ 1608 Ma之间的锆石可能来自玻利维亚的洛玛斯马内切斯造山带。年龄为1544 Ma的锆石群可能与位于马托格罗索州的Cachoeirinha或Rondonia的Serra da Providencia岩浆套有关。1485 Ma、1417 Ma和1411 Ma的锆石可能来自马托格罗索州邻近的圣海伦娜造山带。研究结果表明，Aguapeí沉积物的最大沉积年龄为1.26 Ga，是所分析的碎屑锆石中年龄最小的。锆石U-Pb年龄对阿瓜佩群沉积岩沉积具有重要的时间约束。此外，本文报告的结果为识别该地区尚未发现的岩石提出了新的挑战，这可能会为西南亚马逊克拉通地壳演化提供更完整的框架。
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.