Heat flow measurements in the Northern Mozambique Channel

Abstract

Heat flow in the Northern Mozambique Channel is poorly constrained, with only a few old measurements indicating relatively low values of 55–$62~\text{mW/m}^2$. During the SISMAORE cruise to the Northern Mozambique Channel, we obtained new heat flow measurements at four sites, using sediment corers equipped with thermal probes. Three of the sites yield values of 42–47 $\text{mW/m}^2$, confirming low regional heat flow in this area. Our values are consistent with a Jurassic oceanic lithosphere around Mayotte, although the presence of very thin continental crust or continental fragments could also explain the observed heat flow. Our values do not support a regional thermal anomaly and so do not favor a hotspot model for Mayotte. However, at a fourth site located 30 km east of the submarine volcano that appeared in 2018 east of Mayotte, we measured a very high heat flow value of $235~\text{mW/m}^2$, which we relate to the circulation of hot fluids linked to recent magmatic activity.

Keywords

• Heat flow
• Oceanic lithosphere
• Volcanism
• Northern Mozambique Channel
• Comoros archipelago
• 2018–2021 Mayotte eruption