10.18170/DVN/E0ELD5 Shishun Wang0000-0002-8671-7074(Peking University) Peking University Open Research Data Platform 2021 This data set contains rock magnetic data for fresh and hydrothermally-altered basalt from the Southwest Indian Ridges. These data include alternating-field (AF) demagnetization, thermal demagnetization (TD), temperature-dependent magnetic susceptibility (k-T), isothermal remanent magnetization (IRM) acquisition curves and the unmixed components, low-temperature magnetic property measurements, hysteresis loops, and the first-order reversal curves (FORC). Samples and their lithologies are described in the Excel file named ''Data form.xlsx" with their bulk magnetic parameters as well. Shishun Wang(Peking University)