Abstract The comments to the publication by de Oliviera Chaves et al. (2019) refer to the derivation of eclogite-facies conditions for micaschist from the Paleoproterozoic Itaguara Sequence in the southern Sao Francisco Craton in Brazil. These authors derived peak pressures of 18.5 kbar at 626 °C for this rock using phengite geobarometry. A scrutiny of their analytical data and the applied geothermobarometry led to the conclusion that these pressures were at most 13–14 kbar and possibly even below 10 kbar. Temperatures did not exceed about 600 °C. Thus, melting of the studied micaschist is unlikely. A subduction-related process in the Paleoproterozoic to form the Itaguara Sequence, as suggested by de Oliviera Chaves et al. (2019), must be called in question.

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评论“高压榴辉岩相变质作用和减压熔融记录在与 Itaguara（南圣弗朗西斯科克拉通 - 巴西）可能的蛇绿岩相邻的古元古代增生楔中”

摘要 de Oliviera Chaves 等人对出版物的评论。(2019) 指从巴西圣弗朗西斯科克拉通南部古元古代Itaguara层序推导云母片岩榴辉岩相条件。这些作者使用 phengite 地质气压测量法得出了该岩石在 626 °C 时的峰值压力为 18.5 kbar。对他们的分析数据和所应用的地温气压法的仔细检查得出的结论是，这些压力最多为 13-14 kbar，甚至可能低于 10 kbar。温度不超过约600°C。因此，所研究的云母片不太可能熔化。正如 de Oliviera Chaves 等人所提出的，古元古代中与俯冲相关的过程形成了 Itaguara 层序。（2019），必须提出问题。