The Gamma-ray (GR) and paleomagnetic data from the MZK2813 core in the Qaidam Basin, Northern Tibetan Plateau

Lithologies of the 200-m long core were first described and logged following standard procedures in core logging . The continuous GR data were measured using JHQ-2D logging tool based on JSS-3 gamma logging specification through pipes, with sampling resolution of 1 cm. Cubic non-magnetic boxes (2 cm × 2 cm × 2 cm) were inserted into split core sections parallel to the borehole's vertical axis, with depth and top orientation recorded, yielding 400 samples from a 200 m core (one sample per 0.5 m interval) for magnetostratigraphic dating. All samples underwent stepwise alternating field (AF) demagnetization (17 steps total: 2.5 mT increments below 30 mT, 5–10 mT increments above 80 mT). Remanent magnetization was measured using a 2G 755R cryogenic superconducting magnetometer in a magnetically shielded room (<150 nT background field) at the Institute of Earth Environment, Chinese Academy of Sciences (Xi’an), with a measurement range of 2.0×10⁻¹² to 2.0×10⁻⁴ A·m² and sensitivity of 2.0×10⁻¹² A·m².In most cases, the characteristic remanent magnetization (ChRM) was identified after removing magnetization components below 7.5 mT. Principal component analysis (PCA) using PaleoMag software was employed to determine the ChRM vector from at least four points of the stable high-temperature component. Samples with maximum angular deviation (MAD) greater than 15° or those exhibiting uncertain or irregularly jumping ChRM directions were excluded. A total of 316 samples successfully passed through this screening procedure and used to construct the paleomagnetic pole sequence.