Paleomagnetic study on the Early Triassic red beds from Jiaocheng, Shanxi Province ——Local rotation and tectonic significance

Paleomagnetic and rock magnetic study has been conducted on the Early Triassic red beds of Liujiagou Formation from Jiaocheng, Shanxi Province. Hematite was shown as the main magnetic mineral. After eradicating an initial viscous component at room temperature to -100℃- 200℃, thermal demagnetization shows that most samples contain two remanence components, intermediate-temperature remanence component at 250℃-500℃ and high-temperature component at 500℃-680℃. The intermediate-temperature component has a negative fold test at the 95% confidence level. And the pole position of the intermediate-temperature component in geographic coordinates is correlated with the Middle Jurassic reference pole of the North China Block (NCB) within the 95% confidence, suggesting that it might be a remagnetiza-tion component acquired during the Yanshanian period. The high-temperature component contains both reversal and normal polarities with positive fold test and C-level positive reversal test at the 95% confidence lev