Deciphering the deep Earth heterogeneities from the temperature fluctuation of mantle plumes

Distinguishing deep lower mantle heterogeneities and resolving their physical and chemical properties are challenging due to the difficulty in achieving severe high-temperature and high-pressure conditions simultaneously in mineral experiments. Deep-seated mantle plumes bring these heterogeneities to the Earth's surface, therefore providing a unique insight into the Earth's deep interior. Here, we link the surface temperature fluctuation of mantle plume to the properties of deep-mantle heterogeneities via three-dimensional geodynamic modeling. Our results show that high-viscosity primordial mantle materials significantly increase the surface plume temperature due to their excessive viscous heating, whereas high-density oceanic crust slightly reduces it. Give some estimates for the maximum plume fluctuation temperature through time, the survival of scattered primordial blobs with a high viscosity contrast of ∼10-50 times in the deep-mantle reservoir is required. The temperature variations of the thermochemical mantle plume likely control the observed multiple volcanic episodes of large igneous provinces and periodic changes of volcanic flux along hotspot tracks. •High-viscosity primordial mantle significantly increases surface plume temperature.•High-density oceanic crust slightly reduces surface plume temperature.•Modeling indicates the survival of scattered high-viscosity primitive mantle blobs.