Ladakh Magmatic Arc (LMA)

Scientists have unraveled the geological evolution of the Ladakh Magmatic Arc, a 130-million-year-old record of plate tectonic activity in the northwest Himalaya. The findings shed light on the long and complex processes that led to the formation of the Himalayan mountain system.

Ancient Ocean and Subduction Process

Millions of years before the rise of the Himalaya, present-day Ladakh lay above the ancient Neo-Tethys Ocean. Beneath this ocean, massive slabs of Earth’s crust were pushed into the mantle through a process known as Subduction.

This subduction of the oceanic plate beneath the Eurasian margin eventually led to the formation of the Ladakh Magmatic Arc (LMA).

About Ladakh Magmatic Arc

• The LMA is a belt of igneous rocks located in the Trans-Himalaya.
• It formed over a long geological period from the Jurassic to Eocene epochs (about 201 million to 34 million years ago).
• It represents a long-extinct volcanic system that once generated vast quantities of molten rock.

Key Scientific Findings

• Researchers traced the arc’s evolution by analyzing the chemical composition of rocks.
• The study confirms that the LMA formed due to the northward subduction of the Neo-Tethyan oceanic plate beneath the Eurasian Plate.
• The arc evolved through three major phases of geological activity, marking stages of subduction, maturation, and eventual continental collision.

Source: PIB