Indian Study Explains Formation of Titanium-Rich Lunar Basalts

A new study by researchers from IIT-Kharagpur and the Physical Research Laboratory (PRL), Ahmedabad, has provided fresh insights into the formation of titanium-rich basalts on the Moon. Published in “Geochimica et Cosmochimica Acta”, the research addresses a long-standing puzzle in planetary science regarding why lunar volcanic rocks contain unusually high levels of titanium dioxide compared to Earth.

Unusual Composition of Lunar Basalts

Unlike Earth’s volcanic rocks, which typically contain less than 2% titanium dioxide (TiO₂), some lunar basalts exhibit concentrations as high as 18%. These rocks originated from ancient lava flows formed billions of years ago. Scientists have struggled to explain how such high titanium levels formed under lunar conditions, making this study a significant advancement in understanding the Moon’s geological evolution.

Experimental Approach and Findings

The researchers simulated lunar interior conditions using high-pressure and high-temperature experiments, replicating depths of up to 700 km inside the Moon. Their findings suggest that titanium-rich basalts formed through a complex two-stage process involving melting, chemical interaction and mixing between dense titanium-rich layers and the Moon’s mantle. This model successfully explains the observed composition of lunar basalts, including their titanium and magnesium content.

Role of Ilmenite-Bearing Layer

The study highlights the role of a dense ilmenite-bearing cumulate (IBC) layer formed during the Moon’s early cooling phase. As this layer sank into the mantle, it partially melted and generated titanium-rich magma. Some of this magma remained trapped deep within the Moon, later mixing with rising molten material to produce titanium-rich lava flows that reached the surface over time.

Important Facts for Exams

• Lunar basalts can contain up to 18% titanium dioxide (TiO₂).
• Ilmenite is a titanium-bearing mineral found on the Moon.
• Moon formed around 4.5 billion years ago from a magma ocean.
• High-pressure experiments simulate planetary interior conditions.

Implications for Future Lunar Missions

The findings are expected to aid mission planning for future lunar exploration, including India’s Chandrayaan-4 mission scheduled for 2028. Understanding mineral composition and formation processes can help identify optimal landing sites and guide sample collection strategies. The study also demonstrates India’s growing capability in advanced planetary research and high-pressure experimental science.