A product of continental collision
The graphite deposits in Mohnyin Township are a direct result of the immense geological forces that created the Himalayan mountain range. These deposits are located within the Mogok Metamorphic Belt, a zone of intensely deformed and heated rocks running north-to-south through Myanmar. This belt is a region that experienced deep transformation during the collision of the Indian and Eurasian tectonic plates, an event that began between 59 and 40 million years ago.
The process started with ancient marine sediments, full of organic matter like algae and other microorganisms, that were buried and compacted over millions of years. As the Indian plate drove northward, these carbonaceous sedimentary rocks were caught in the continental collision zone. They were subjected to extreme temperatures, often exceeding 500°C, and immense pressures. This intense metamorphic environment cooked the buried organic material, driving off volatile elements like hydrogen and oxygen and progressively rearranging the remaining carbon atoms into the perfectly ordered, hexagonal sheets characteristic of crystalline graphite. The host rocks for this graphite are typically high-grade metamorphic rocks such as schists and gneisses.
Crystalline and pure
The graphite found here is of the crystalline flake type, characterized by visible, flat, plate-like particles. The slow formation process allowed for the growth of large, well-ordered crystals. This high degree of crystallinity gives the graphite superior properties, including excellent electrical and thermal conductivity, which make it highly valuable.
High-purity graphite, defined as having a carbon content over 99.9%, is important for many advanced technologies. This material is a component in the anodes of lithium-ion batteries, where its purity allows for efficient energy storage and discharge. It is also used to make crucibles for manufacturing semiconductors and silicon crystals, as its ability to withstand extreme heat without introducing contaminants is important. Other applications include high-temperature lubricants, advanced composite materials for the aerospace industry, and electrodes for electric arc furnaces in steelmaking. The unique geological history of the Mohnyin deposits results in a natural graphite with qualities that can compete with more expensive, synthetically produced versions.