Resurgence of Lunar Volcanism: Role of Localized Radioactive Enrichment in a Numerical Model of Magmatism and Mantle Convection

TL;DR

This paper presents a 2-D numerical model demonstrating how localized radioactive enrichment in the Moon's mantle can cause multiple peaks of volcanic activity over billions of years, explaining the resurgence of lunar volcanism.

Contribution

It introduces a novel numerical model that links localized radioactive enrichment to the long-term, multi-peak lunar volcanism, highlighting mechanisms behind the resurgence of volcanic activity.

Findings

Localized radioactive enrichment influences long-term lunar volcanism

Two peaks of volcanic activity are explained by mantle plume dynamics

Radioactive enrichment is key to sustained magmatism over billions of years

Abstract

We develop a 2-D numerical model of magmatism and mantle convection to understand the volcanism on the Procellarum KREEP terrane (PKT) of the Moon, which continued for billions of years with two peaks of activities at 3.5-4 Gyr ago and around 2 Gyr ago. In our model, the effects of the PKT on lunar evolution are considered by initially imposing a region of localized radioactive enrichment. The calculated volcanism has two peaks induced by different mechanisms. The first peak occurs at 3.5-4 Gyr ago when magma generated in the deep mantle by internal heating ascends to the surface as partially molten plumes. The basaltic blocks in the uppermost mantle formed by this magmatism, then, sink to the deep mantle, triggering further plumes that cause the resurgence of volcanism at $\sim$2 Gyr ago. Our model shows that localized radioactive enrichment is important for the long-lasting volcanism with a couple of peaks.