Did the circum-Rodinia subduction trigger the Neoproterozoic rifting along the Congo–Kalahari Craton margin?

Reply to Comment by Heilbron and Valeriano on “Tectono Metamorphic Evolution of the Central Ribeira Belt, Brazil: A Case of Late Neoproterozoic Intracontinental Orogeny and Flow of Partially Molten Deep Crust During the Assembly of West Gondwana”

“…The available isotopic data for these metamafic rocks show highly radiogenic Nd and Sr signatures, suggesting juvenile mantle-derived magmatism (Peixoto et al, 2017 and references therein). The geochemical and isotopic variability recorded in both felsic and mafic magmatism along the Ribeira Belt suggests heterogeneous mixing processes of different crustaland mantle-derived sources, which is compatible with the interpretation of extensional processes within the Rodinia supercontinent (Konopásek et al, 2018;Passarelli et al, 2019). In this alternative interpretation, the arc-related geochemical signatures recorded 10.1029/2020TC006307 in these rocks are associated with inheritance of the source rocks from older geodynamic processes (e.g., Bea et al, 2003;Konopásek et al, 2018) or are generated by magmatic interactions between mantle-and crustal-derived magmas unrelated to subduction settings (e.g., Arculus, 2003;Cambeses et al, 2015Cambeses et al, , 2019Hawkesworth et al, 1995;Maurice et al, 2009;Zhang et al, 2011).…”

“…Such a tectonic scenario is unlikely if one considers the correlation of the metasedimentary belts of West Congo Belt (north of Luanda Shear Zone, Monié et al, 2012) and the western edge of the Angola Block (De Carvalho et al, 2000) and the crustal architecture of the Congo-Angola Craton (Jelsma et al, 2018;Thiéblemont et al, 2018). Furthermore, recent geochemical and geochronologic data from late Tonian bimodal magmatism and detrital zircon provenance studies from Cryogenian metasedimentary rocks in both Atlantic margins have also questioned the existence of a large Adamastor ocean in between the Ribeira and Dom Feliciano belts in Brazil and the Kaoko belt in Namibia (Konopásek et al, 2017(Konopásek et al, , 2018(Konopásek et al, , 2020.…”

“…In contrast to the statements by Heibron and Valeriano (2020), aspects of the models involving subduction-collision processes that are problematic have been sufficiently discussed in our paper (Meira, Garcia-Casco, Hyppolito, et al, 2019) and reinforced here. As discussed in this reply and other contributions (e.g., Cavalcante et al, 2019;Fossen et al, 2020;Konopásek et al, 2018Konopásek et al, , 2020, these critical aspects include the space problem to accommodate large oceanic domains in the context of the semi-confined orogenic setting, the chronology of collisional events and spatial distribution of metamorphic ages along the different blocks (or the supposed "terranes"), and the interpretation of calc-alkaline magmatism as unequivocal evidence for subduction processes.…”

“…We appreciate Heilbron and Valeriano (2020) for giving us the opportunity to further clarify the tectonic implications of the data presented in Meira, Garcia-Casco, Hyppolito et al (2019) and to discuss the different tectonic interpretations of these new data for the major Brasiliano/Pan-African Ribeira-Araçuaí-West Congo orogenic system, in particular in the context of recent papers that reevaluate the prevailing tectonic models for some Brasiliano/Pan-African orogens (Cavalcante et al, 2019;De Toni et al, 2020;Fossen et al, 2017Fossen et al, , 2020Konopásek et al, 2017Konopásek et al, , 2018Konopásek et al, , 2020Meira et al, 2015;Meira, Garcia-Casco, Hyppolito et al 2019;Meira, García-Casco, Juliani, et al, 2019;Oriolo et al, 2016, among others).…”

Chemical variation, modal composition and classification of granitoids

“…Regardless of the real setting, it will be characterized by a strong depletion of HFSE relative to Large Ion Lithophile Elements (LILE) and thus conspicuous negative Nb-Ta anomalies, e.g. in the NMORB-normalized spiderplots (Janoušek et al 2010;Konopásek et al 2018).…”