Paleomagnetic Constraints on the Separation of the Olongbuluke Block From the North China Block During the Late Cambrian–Middle Ordovician and Its Tectonic Significance

Abstract The collisional evolution of the micro‐blocks in the northeastern Tibetan Plateau is relatively well constrained. However, the reason why a fragment of the North China Block, the Olongbuluke Block, became separated from North China by the Central Qilian Block (a fragment of the South China Block) remains unclear. We present a robust paleomagnetic pole from Floian–Dapingian limestones of the Olongbuluke Block. Comparison with coeval data from North China indicates that the Olongbuluke Block rifted southward before the Late Cambrian and by the Floian–Dapingian had attained a paleolatitudinal separation of ∼24.5° ± 8.0°. Thereafter, it underwent a ∼120°–130° counterclockwise rotation. Integrating geological and paleontological evidence, we infer that after separating from North China, the Olongbuluke Block collided with the South China Block, leading to the detachment of the Central Qilian Block. Subsequently, before re‐colliding with North China, the Olongbuluke and Central Qilian blocks rotated, ultimately shaping the present tectonic configuration of the northeastern Tibetan Plateau.