Minas Gerais state forms part of the Eastern Brazilian pegmatite province (EBPP), which is home to high-quality lithium-bearing minerals, spodumene and petalite. The EBPP is one of the most significant granitic pegmatite provinces in the world and hosts important industrial minerals, including quartz, feldspar, mica, and beryl.
The Itinga Project is located in the Araçuaí Pegmatite District (APD) within the EBPP where the pegmatites are characterized by supracrustal rocks composed of mica schist from the Salina Formation. The rocks are intruded by Neoproterozoic granitic bodies and are a source of volatile mineralizing fluids.
Lithium mineralization on the Itinga Project occurs within a halo of pegmatite dikes and apophyses that have formed within the rocks surrounding the Neoproterozoic granitic intrusions. The mineralized pegmatites are dispersed along a complex and crosscutting system of northeast- and northwest-oriented faults that were exploited by the dikes.
The APD holds Brazil's largest lithium reserves, most of which are located in Araçuaí, Itinga, and surrounding areas. Within the APD, more than one hundred pegmatitic occurrences are known.
The APD is composed of residual pegmatites derived from G4 granitic bodies (two-mica granite), which are rich in fluids, such as water, silica, alumina, as well as alkali, rare, and other volatile elements. These granitic bodies are responsible for the pegmatites of Araçuaí and Itinga that we see today, which bear lithium minerals, gems, and cassiterite.
The lithium-bearing pegmatites in the Araçuaí region were formed during the final crystallization stages of the granite. Residual volatile fluids accumulated at the top of the granitic magma chamber and entered the fractures and fault zones of the host rock. These granitic fluids from G4 granite intruded the rock during the Cambrian period between 535 and 490 million years ago.