Magnetic properties indicate the sources of hadal sediments in the Yap Trench, northwest Pacific Ocean

Abstract

Magnetic minerals in marine sediments are often masked by the primary natural remanent magnetization and material source signals. In order to understand sedimentary environment and sources of sediments in the abyss, we studied 126 samples of five bottom surface cores collected by the Jiaolong Submersible at 4000–7000 m in depth during the third stage of the China’s 38th Ocean Voyage. The magnetic properties of the sediments were analyzed using Thermosusceptibility (k-T) curves and Day plot. The results show that the magnetic minerals in the sediments of the Yap Trench are mainly maghemite, and the overall magnetic and soft magnetic properties were strong. The magnetic particles of sediments are dominated by pseudo single domains (PSD) grains. The main source of sediment is locally-derived basalt debris and volcanic debris, and the process of sedimentation is gravity-like flow deposition.