Petrography and geochronology of the Furquim Quartzite, an eastern extension of the Itacolomi Group (Quadrilátero Ferrífero, Minas Gerais)

Abstract

This paper presents the results of a petrographic and geochronological investigation of the Furquim Quartzite (FQ) to establish its stratigraphic correlation to quartzitic units of the Quadrilátero Ferrífero (QF) province. The Quartzite comprises a ca. 20km long and 1-6km wide ridge overlying discordantly the Archean to Paleoproterozoic gneissic basement and rocks of the Archean Rio das Velhas Supergroup between the city Mariana and the town Furquim, southeast of the QF. Despite the discordant contacts, previous field-based stratigraphic studies considered the Furquim Quartzite as part of the Archean Maquiné Group -top unit of the Rio das Velhas Supergroup. U-Pb zircon geochronology via LA-ICP-MS identified several detrital populations ranging from Paleoproterozoic to Archean age. The youngest population of 2087±19 Ma defines the maximum age for the sedimentation of the precursor sandstone. This age can be correlated to be the age of the youngest zircon population of the Itacolomi Group quartzites in the QF. Thus, in contrast to previous studies, the results indicate that the FQ is an eastern extension of the Itacolomi Group, the youngest unit of the Paleoproterozoic Minas Supergroup.

Depositional systems, sequence stratigraphy, and sedimentary provenance of the Palaeoproterozoic Minas Supergroup and Itacolomi Group, Quadrilátero Ferrífero, Brazil

“…The Itacolomi Group (Figure 13F, N = 526, compiled from Machado et al 1996, Jordt-Evangelista et al 2015and Duque 2018 shows a similar distribution (bimodal, with the same age ranges), but with different relative probabilities: the Minas Accretionary Orogeny peak is significantly greater than the Archaean age peak.…”

“…A statistical analysis (Figure 13) of the detrital zircon U-Pb database (compiled from Machado et al 1992, Koglin et al 2014, Jordt-Evangelista et al 2015, Nunes 2016, Dutra 2017, Duque 2018 for the Minas-Itacolomi stratigraphic units was carried out, through histograms, Probability Density Plots (PDPs), and adaptive Kernel Density Estimates (KDEs) from the Java-based DensityPlotter software (Vermeesch 2012). The PDP and histogram from the compilation of all the available Moeda Formation zircon U-Pb data were not carried out due to the large amount of spots/zircons, (therefore, large 207 Pb/ 206 Pb ages data set, N = 1,980), which tend to over smooth the probability density function (Vermeesch 2012).…”

“…To overcome this major problem, sedimentary provenance geochronological studies regarding detrital zircons have been carried out to estimate the life span of the sedimentary basins (Renger et al 1994, Koglin et al 2014, Mendes et al 2014, Nunes 2016. Furthermore, this article also presents a detrital zircon age data compilation (database from Machado et al 1992, Koglin et al 2014, Jordt-Evangelista et al 2015, Nunes 2016, Dutra 2017, Duque 2018, in order to comprehend the provenance differences in the many geodynamic stages of the Minas-Itacolomi basins. In summary, this article presents, for the first time in the geological studies of the QF, a complete logging and description of sedimentary facies, depositional systems, and sequences (under the sequence stratigraphy approach), together with an U-Pb detrital zircon geochronological data compilation for provenance studies of the Minas-Itacolomi Palaeoproterozoic basins.…”

Pseudosection modeling and U-Pb geochronology on Piranga schists: role of Brasiliano Orogeny in the Southeastern Quadrilátero Ferrífero, Minas Gerais, Brazil

“…A comparison between the frequency histogram and probability curves for all available U-Pb data for the studied metapelites and Rio das Velhas Supergroup (Nunes 2016, Sousa 2016, Moeda Formation (Nunes 2016, Sousa 2016, Dopico et al 2017, Sabará and Itacolomi Groups (Machado et al 1996, Hartman et al 2006, Jordt-Evangelista et al 2015, Dopico et al 2017, Duque 2018 provides insights into similarities and differences between the considered lithologies. Based on Figure 6, a prominent ca.…”

“…Bulk composition of each sample, used for pseudosection calculation, is available in Supplementary Table A4. Machado et al 1996, Hartmann et al 2006, Jordt-Evangelista et al 2015, Sousa 2016, Nunes 2016, Dopico et al 2017, Duque 2018.…”