Paleomagnetism of Late Triassic Volcanic Rocks From the Southern Qiangtang Block, Tibet: Constrains on the Closure of the Paleo-Tethys Ocean

<p>To better constrain the drift history of the <strong>South Qiangtang block</strong> and the closure of the <strong>Paleo-Tethys Ocean</strong>, we report a paleomagnetic result isolated from 25 sites (199 samples) of Late Triassic volcanic rocks from the Xiaoqiebao Formation. The directions of the characteristic remanent magnetization isolated from these rocks pass both fold- and reversal tests, and are likely primary magnetizations. On base of these data, we estimate that the South Qiangtang block occupied a paleolatitude of <strong>30.1&#176;N&#177;4.6 at 222Ma</strong>. When combined with existing paleomagnetic constraints, these new results indicate that the South Qiangtang block moved rapidly northward between the middle Permian and Late Triassic, at an average south&#8208;north speed of <strong>~13.4 cm/yr</strong> during middle Permian to Late Triassic. Our new data further suggest that the Paleo-Tethys likely closed by ~222Ma, and the north-south width of the Neo- Tethys Ocean was reached ca. 7000 km at this time.</p>