The history of our planet is written in its rocks and lead is one of its most precious chronometers. By studying the different versions of this element called isotopes, scientists can go back in time. Normally, Earth’s chemical composition would reflect that of the primitive meteorites that formed it billions of years ago. However, when analyzing the earth’s crust, the count is not there: a massive quantity of old lead is missing.
This anomaly is so marked that it sometimes gives the impression, by mistake, that the Earth is much younger than it really is. Until now, theories suggested that this lead may have been embedded in the planet’s liquid iron core during its formation. But without concrete proof, this hypothesis remained just that: a hypothesis.
This is where researchers from Nanyang Technological University (NTU) in Singapore come in. In a study published on February 16, 2026 in the specialist journal Nature Communications, the team led by Ryan Whalen used ultra-powerful numerical simulations to understand the behavior of lead at extreme depths. Scientists have focused on how lead binds with sulfur to form lead sulfide in the Earth’s mantle.
According to The Debrief, the results are fascinating. Under enormous pressure and temperatures approaching 5,000°C, lead sulfide does not melt but remains solid and transforms into new chemical structures. These reservoirs would act as geological safes, keeping the original lead trapped far from the surface and protected from any interaction with the uranium that is usually used to date it.
Chemical structures never seen before
The study reveals that pressure stabilizes two specific forms of lead sulfide: PbS₂ and PbS₃ – a discovery that changes everything. PbS₂ is so strong that it remains trapped in the depths, which explains why old lead is missing during our surface samples.
Conversely, PbS₃ has a slightly lower melting point. This allows it to slowly seep toward the crust, ending up in the volcanic rocks we see today. This two-speed mechanism finally explains why surface measurements are so different from what meteorite theory predicted.
This breakthrough is not just a victory for geology enthusiasts. It offers a new look at the formation of all rocky planets. If lead behaves like this on Earth, it is very likely that these processes also take place on Mars or Venus, which would change our understanding of the evolution of the world around us.
The next step for the Singapore team will be to move from the supercomputers to the laboratory. She plans to use diamond anvil presses to try to physically recreate these extreme conditions and validate the existence of these new compounds. The mystery of the missing lead, which has held science in check for decades, now appears on the verge of being definitively closed.
