Abstract A kitagohaite grain, measuring approximately 1.0 mm, was retrieved from an alluvial gold gravity concentrate from the southeastern Quadrilátero Ferrífero (QFe), Mariana, Brazil. The grain exhibits a cubic structure, whitish-steel-gray, and has a metallic luster. It is composed of Wt. 94.42% Pt and 5.56% Cu (n=9), yielding the empirical formula Pt6.78Cu1.22. This groundbreaking discovery marks the first documented occurrence of kitagohaite in South America. This hydrothermal deposition of kitagohaite indicates that its mineralization is constrained to temperatures <500º C, as inferred by the stability of synthetic Pt7Cu. 10 1 0 1. mm QFe, QFe , (QFe) Mariana Brazil structure whitishsteelgray, whitishsteelgray whitish steel gray, gray whitish-steel-gray luster Wt 9442 94 42 94.42 556 5 56 5.56 n=9, n9 n n=9 9 (n=9) Pt678Cu122 PtCu Pt6 78Cu1 22 Pt6.78Cu1.22 America 500º º C Pt7Cu (QFe 944 4 94.4 55 5.5 n= (n=9 Pt678Cu12 78Cu 2 Pt6.78Cu1.2 94. 5. (n= Pt678Cu1 Pt6.78Cu1. (n Pt678Cu Pt6.78Cu1 Pt6.78Cu

Abstract Objectives: This study aims to investigate if a sampling method using virtual networks is feasible to survey AS adoption among this “hard-to-reach” population of Brazilian doctors. Methods: An online piloted 11-point structured survey questionnaire (designed using Googleforms®) probed the actual treatment patterns for adult patients with PTMCs, including treatment decision-making nonoperative options, was undertaken between 10 November and 30 November 2020. Participants were reached by the mobile phone Application (APP) and a snowball sampling strategy was used to recruit a total of 4783 members (maximum number of potential reach), which is the total of doctors of the all 21 social media WhatsApp® groups. Results: From a total of 4783 members (maximum number of potential reach), there were 657 (13.7%) doctors (actual reach) who clicked the web link of the questionnaire, out of whom 512 (10.7%) fully completed the online survey. Among the survey respondents, 361 were endocrinologists (70.5%) and 151 were surgeons (29.5%). Overall, for low-risk PTMCs in an elderly patient, 118 responders (23%) recommend AS, while 390 (76%) recommend immediate surgery as the management, including lobectomy (18.5%) and Total Thyroidectomy (58.2%). The present responders tended to recommend surgery for PTMCs that were located adjacent to the dorsal surface of the thyroid, were multiple, or raised the size during the follow-up. Conclusion: Using snowball sampling strategy as an innovative route to conduct surveys was feasible and applicable but the rate of response was still very low. Our data also suggests the need to investigate if AS is embraced by Brazilian doctors. Objectives hardtoreach hard reach “hard-to-reach Methods 11point point 11 designed Googleforms® Googleforms decisionmaking decision making options 1 3 2020 APP (APP 478 maximum reach, , 2 WhatsApp groups Results 65 13.7% 137 13 7 (13.7% 51 10.7% 107 (10.7% respondents 36 70.5% 705 70 5 (70.5% 15 29.5%. 295 29.5% . 29 (29.5%) Overall lowrisk low risk patient 23% 23 (23% 39 76% 76 (76% management 18.5% 185 18 (18.5% 58.2%. 582 58.2% 58 (58.2%) thyroid multiple followup. followup follow up. up follow-up Conclusion 202 47 6 13.7 (13.7 10.7 (10.7 70.5 (70.5 29.5 (29.5% (23 (76 18.5 (18.5 58.2 (58.2% 20 4 13. (13. 10. (10. 70. (70. 29. (29.5 (2 (7 18. (18. 58. (58.2 (13 (10 (70 (29. ( (18 (58. (1 (29 (58 (5

Abstract The Moeda Formation (Caraça Group, base of Minas Supergroup) registers the initial rift stages of the Minas Basin in the Quadrilátero Ferrífero, Southern São Francisco craton, SE-Brazil. We present stratigraphic and U-Pb detrital zircon dating analyses of the Moeda Formation that contribute to the comprehension of its sedimentary evolution in the southernmost Gandarela and Ouro Fino synclines (Central-Eastern Quadrilátero Ferrifero). The Moeda Formation sequence consists of a basal proximal alluvial fan with clast-supported conglomerates, grading upward into an alluvial floodplain with quartz arenites, and upper massive sandstones from distal fluvial fans. Because the Moeda Formation is normally limited by similar lithologies at both its base (Nova Lima Group, Rio das Velhas Supergroup) and top (Batatal Formation, uppermost Caraça Group) and stratigraphic inversion has occurred in the study area, U-Pb detrital zircon dating was also extended to these units to differentiate them stratigraphically. The youngest clusters of detrital zircon ages in the Nova Lima Group and Moeda and Batatal formations were 2716, 2777 and 2786 Ma, respectively. Based on our data and relevant literature, the depositional age of the Moeda Formation was interpreted as between 2716 and 2520 Ma with the Mesoarchean continental crust, the Rio das Velhas Supergroup and the Archean TTG complexes as its main source areas.

Abstract Orthogneisses associated with metavolcanosedimentary successions related to the 1000 - 920 Ma Cariris Velhos event occur mainly in a ca. 700 km-long sigmoidal-shaped belt that crosscuts the Transversal Zone of the Borborema Province and extends to the fold belts located in its southern or external zone (part of the Riacho do Pontal and Sergipano orogens). Despite its importance, the tectonic setting and the role of those rocks in the geological evolution of the Borborema Province are contentious and not yet well understood. New zircon U-Pb SHRIMP data on an augen-gneiss sill of the Afeição Suite intruding mica-schists mapped as part of the Santa Filomena Complex yielded a Concordia Age of 974 ± 11 Ma, indicating that at least part of the metasedimentary rocks in the internal zone of the Riacho do Pontal Orogen are Tonian or older and possibly related to the Cariris Velhos event. Hf-in-zircon isotope data are presented for the first time for Cariris Velhos-related ortho-derived rocks of the Afeição Suite. Analyzed samples yielded εHf(t) in a narrow range between -1.51 and +2.41, with associated TDMHf of 1.6-1.4 Ga, similar to previously obtained Nd isotope data with εNd(t) = -1.0 to +3.1 and TDMNd of 1.5-1.2 Ga. A possible scenario to explain both the geochemical features and the moderately juvenile to slightly evolved, near-chondritic Hf and Nd isotope signatures is a continental arc setting, where fractionated melts produced in the supra-subduction zone mantle wedge carrying a Tonian juvenile signature became contaminated with discrete amounts of Archean-Paleoproterozoic continental crust during ascent, producing Mesoproterozoic model ages which represent the mixture of those two end-members.

Formações ferríferas são importantes fontes de informações sobre a evolução da hidrosfera, atmosfera, biosfera e litosfera da Terra. Esse trabalho reúne dados geoquímicos de elementos maiores, menores e traços (incluindo os elementos terras raras) dos itabiritos silicoso, anfibolítico e magnetítico da Formação Cauê provenientes da região de Serra Azul (QF).Em se tratando das concentrações de elementos-traço, considerados traçadores de contaminação detrital, pode-se inferir que o tipo magnetítico é o que possui uma maior contaminação e que o silicoso, a menor.Embora existam diferenças no somatório total de ETR nos três diferentes tipos de itabiritos estudados, na região de Serra Azul, não foi possível verificar discrepâncias muito significativas no espectro de ETR dos três diferentes tipos estudados. São características comuns aos três tipos de itabiritos: i) anomalias positivas de Eu (Planavsky et al., 2010); ii) enriquecimento em ETR pesados em relação aos leves; iii) razões (Sm/Yb)SN<1 e (Eu/Sm)SN>1 (Bau & Möller, 1993). Os itabiritos magnetítico e o silicoso possuem ainda em comum anomalias positivas de Y, uma característica que aparece em algumas amostras do tipo anfibolítico também. As outras amostras de itabirito anfibolítico possuem anomalias negativas de Y.

Banded iron formations are important providers of information about the evolution of the hydrosphere, atmosphere, biosphere and lithosphere of the Earth. This study gathers data from the geochemical investigation of major, minor and trace elements (including rare earth elements) of the siliceous, amphibolitic and magnetitic types of itabirite from the Cauê Formation, sampled in the Serra Azul region (Quadrilátero Ferrífero).Observing the trace elements described as tracers of detrital contamination can be inferred that the magnetitic itabirite has the highest contamination and that the siliceous type has the lowest one.Although there are differences in the total sum of REE in the three itabirite types of Serra Azul, there are no discrepancies in the REE spectrum of each type. The itabirite types have as common characteristics in their REE spectrum: i) positive Eu anomalies (Planavsky et al., 2010); ii) HREE enrichment in relation to the LREE; iii) ratios of (Sm/Yb)SN<1 and (Eu/Sm)SN>1 (Bau & Möller, 1993). The magnetitic and the siliceous itabirites had positive Y anomalies, a common characteristic that appeared in some amphibolitic samples. On the other hand, the other amphibolitic samples had negative Y anomalies.