# Olivine’s high radiative conductivity increases slab temperature by up to 200K

## TL;DR

Olivine's radiative conductivity increases slab temperatures by up to 200K, affecting subduction dynamics and water transport into Earth's interior.

## Contribution

The study reveals that radiative thermal conductivity in olivine significantly impacts slab temperatures and subduction processes.

## Key findings

- Radiative heat transport accounts for ~40% of olivine's thermal conductivity at high P and T.
- Including radiative heating raises slab temperatures by 100−200 K compared to models without it.
- Older slabs and faster subduction allow water-bearing minerals to reach the Mantle Transition Zone.

## Abstract

The thermal evolution of slabs governs their subduction dynamics and the transport of water into Earth’s interior. However, current slab subduction models often neglect the contribution of radiative thermal conductivity (i.e., heat transport by light) due to the limited constraints on the opacity of minerals at high pressure (P) and temperature (T). Here, using optical experiments at high P, T conditions, we show that the radiative contribution accounts for ~40% of the total heat transport in olivine, the dominant mineral of the upper mantle. Using 2D thermo-kinematic modelling, we quantify the effect of radiative thermal conductivity on slab temperature exploring different ages and subduction velocities. When radiative heating is included, slabs temperatures are ~100−200 K higher than in the models that ignore this contribution. Consequently, water-bearing minerals can reach the Mantle Transition Zone (~410−660 km) only in old slabs (>60 Myrs) and/or at high subduction velocities (≥10 cm/year).

Experiments show that olivine is transparent at high pressure and temperature, with radiative heat transport representing 40% of olivine’s thermal conductivity. Heat radiation enhances slab’s heating rate and affects subduction dynamics.