SIGNIFICADO DA OCORRÊNCIA DE FOSFATOS E BORATOS DE ALUMÍNIO NO CONTATO ENTRE OS SUPERGRUPOS RIO PARAÚNA E ESPINHAÇO NA REGIÃO DE DIAMANTINA, MINAS GERAIS, BRASIL
SIGNIFICADO DA OCORRÊNCIA DE FOSFATOS E BORATOS DE ALUMÍNIO NO CONTATO ENTRE OS SUPERGRUPOS RIO PARAÚNA E ESPINHAÇO NA REGIÃO DE DIAMANTINA, MINAS GERAIS, BRASIL
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巴西米纳斯吉拉斯州里约帕拉乌纳超级集团和迪亚曼蒂纳区的埃斯皮尼亚乔 NA REGIÍ DE DIAMANTINA 的标志
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
Dietrich Ackermand
中科院分区：
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作者：
A. Horn;Giulio Morteani;Dietrich Ackermand
在迪亚曼蒂纳（巴西米纳斯吉拉斯州）附近上太古代Barao de Guacui组和Bandeirinha组之间接触处的白云母-蓝晶石石英岩和/或白云母-蓝晶石片岩中，可以发现五种岩石类型，它们定义了矿物组合：1：青金石、蓝晶石; 2：青金石、辉石、蓝晶石; 3：青金石、软闪石、电气石; 4：青金石、svanbergite、电气石; 5：dumortierite、蓝晶石。所有岩石类型中的其他相是石英和白云母/绢云母。整个岩石的化学性质影响了单个矿物的化学成分。这些矿物的化学成分被解释为铝的沉淀，在中元古界的Barao de Guacui组的太古代交代沉积物上，在Sabka条件下的高碱性湖泊中的富磷和富硼沉积岩。在Brasiliano事件期间，（680- 450 Ma）绿片岩变质作用及伴随的逆冲推覆构造和面理的构造作用。也发生了青金石的移动和沉积进入石英脉，切割了上覆和下覆单元。铝磷酸盐矿物变得重要，因为它们可以帮助更精确地确定Rio Parauna和Espinhaco超群之间的接触。
Within a muscovite-kyanite quartzite and/or muscovite-kyanite schist at the contact between the UpperArchean Barao de Guacui Formation and the Bandeirinha Formation near Diamantina (State of MinasGerais, Brazil) five rock types defining mineral assemblages can be found: 1: lazulite, kyanite, 2: lazulite,augelite, kyanite; 3: lazulite, amblygonite, tourmaline; 4: lazulite, svanbergite, tourmaline, and 5:dumortierite, kyanite. Additional phases in all rock types are quartz and muscovite/sericite. The wholerock chemistry influences the chemical composition of the individual minerals.These ocurrences are interpreted as precipitation of aluminium, phosphorous and boron-rich sedimentaryrocks in highly alcaline lakes under sabka conditions in the Middle Proterozoic on the Archeanmetasediments of the Barao de Guacui Formation.During the Brasiliano event (680-450Ma) a greenschist metamorphism and associated tectonism withthrusting the actual texture and foliation were formed. Mobilization of lazulite and its deposition intoquartz veins, cutting the over- and underlain units occurred, too.The aluminophosphate minerals get importance because they could help to define more precisely thecontact between the Rio Parauna and Espinhaco supergroups.