A Tectonically Active Region
The Nattaung Volcanic Field is caused by immense geological forces shaping Southeast Asia. It sits within a complex and active tectonic region dominated by the ongoing collision between the Indian and Eurasian plates. This collision produces major fault systems, including the nearby Sagaing Fault, a massive right-lateral strike-slip fault that runs for approximately 1,400 kilometers through central Myanmar. This fault accommodates a significant portion of the tectonic strain as the Indian Plate pushes northward.
The volcanism in this part of Myanmar is geologically very young, belonging to the Quaternary period, which began 2.6 million years ago. The activity is linked to a process known as slab tearing, where the subducting Indian oceanic plate is tearing away from the more buoyant Indian continental plate. This tear, or "slab window," allows hotter asthenospheric mantle material to rise, decompress, and melt, ultimately feeding magma to the surface. This mechanism explains the presence of small-scale, recent volcanic activity in areas like Nattaung, distinct from the larger volcanic arcs found elsewhere. The volcanic field itself consists of features like dolerite dykes, which are vertical sheets of solidified magma that intruded into existing rock layers.