The Espinhaço Supergroup at the craton-orogen transition in Serra do Cipó-Brazil: Multi-statistical analyses of new and compiled detrital zircon U-Pb ages

Abstract

The Southern Espinhaço Range, located at the boundary between the São Francisco Craton and the Araçuaí Orogen, is a key geological province in western Gondwana. This study aims to improve the stratigraphic models at its southern limits, focusing on the Serra do Cipó region in Minas Gerais, Brazil. By compiling a comprehensive regional U-Pb detrital zircon age database and integrating new LA-ICPM-MS geochronological data, we established statistical patterns to determine provenance and propose stratigraphic correlations. Detrital zircon age data were analysed using kernel density estimates, Kolmogorov-Smirnov (KS) tests, and Multidimensional Scaling (MDS), revealing three statistically distinct regional affiliation groups: pre-Espinhaço, Espinhaço and Macaúbas-Jequitaí. Our findings show that pre-Bambuí siliciclastic rocks in the Serra do Cipó region strongly correlate with the Espinhaço Supergroup, particularly the Santa Rita and Galho do Miguel formations, rather than the younger Macaúbas Group or pre-Espinhaço units, allowing a for re-evaluation of previous stratigraphic models in this area. The youngest zircon grains indicate maximum deposition of Calymmian (1581 ± 35 Ma, 1579 ± 40 Ma), Statherian (1613 ± 47 Ma, 1656 ± 26 Ma), and Orosirian (1831 ± 26 Ma) ages. Detrital zircon ages suggest that sediment provenance was dominated by Neoarchaean to Paleoproterozoic cratonic sources and Mesoproterozoic magmatic events related to Espinhaço Basin rifting. Limited Calymmian-age zircon grains suggest distal sediment sources. This study refines the understanding of the Espinhaço Supergroup distribution and its role in the tectono-sedimentary history of western Gondwana, emphasizing the need for revised geological mapping at its southern limits.