Rhythms of Brazil

Brazil, a country famous for its music, glitter and Carnival, contains a large proportion of some of the planet’s largest natural resources: the vast rain-forests, the largest river system in the world and enormous mineral reserves.

Dancer at the Rio Carnival Although not on the same scale, Brazil also plays host to other interesting mineral deposits such as the carbonatite mineral intrusions in the Jacupiranga region in the state of Sao Paolo. The melt and fluid inclusions contained within these carbonatites can be used to calculate trapping pressures, which are indicative of the approximate depth of origin of the mineral vein in the earth’s crust.

Detailed analysis of carbonatites can yield characteristic information about the movement of tectonic plates. These plates are constantly shifting, as they have been doing for billions of years. This involves huge pressure, heat and power: see the amazing sequence here.

To understand the sequence Dr. Emma Salvioli-Mariani of the Università di Parma, Italy, has been characterising these carbonatites using a variety of techniques. Qualitative analysis of the small inclusions was performed using energy dispersive x-ray analysis in the SEM, whilst ICP and ICP-MS were used for major and trace element analysis from whole rock samples. Detailed thermometric analysis by studying the homogenization temperatures of inclusions was carried out using the Linkam THMS600 for temperatures up to 584°C, and the Linkam TS1500 up to 1194°C.

Carbonatite from Jacupiranga, Brazil. This rock is compound of calcite, magnetite and olivine

For the full story please refer to Dr. Salvioli-Mariani’s excellent paper:  “Late veins of C3 carbonatite intrusion from Jacupiranga complex (southern Brazil): fluid and melt inclusions and mineralogy”.