A high-resolution magnetic record of Chinese stalagmite within the Blake interval

We present a decadal-scale paleomagnetic analysis of a stalagmite collected from Shuixi Cave, southwest China, spanning 89−123 ka. Our findings include: (1) Magnetite is the dominant magnetic mineral, and paleomagnetic directions can be obtained via demagnetization; (2) Magnetic scanning at 0.1-mm intervals resolves key magnetic features, identifying eight reversed periods; (3) The consistency between two measurements demonstrates the reliability of in-situ magnetic scanning and shows that reversed zones can be identified through changes in inclination or declination. By comparisons with other geomagnetic records, we propose that the Blake interval comprises three major phases, namely the Blake, post-Blake, and Skalamaelifell, characterized by four reversed intervals between 108,810−119,090 yr BP, two between 99,780−103,140 yr BP, and two between 90,950−94,470 yr BP, respectively. These decadal-resolution results illuminate the fine structure of the Blake interval and highlight the significant potential of in-situ magnetic scanning of geomagnetic excursions using precisely dated speleothems.