The South Qiangtang block of the Qinghai‐Tibet Plateau represents an area critical to understanding the late Paleozoic and early Mesozoic history of the Tethyan realm, but its drift history remains poorly constrained. Here we report a new quantitative paleogeographic constraint for the South Qiangtang block from a paleomagnetic study of Late Triassic volcanic rocks of the Xiaoqiebao Formation. A characteristic remanent magnetization isolated from 25 sites passes both fold‐ and reversal tests, and likely represents a primary magnetization. On the basis of these data, we estimate that the South Qiangtang block occupied a paleolatitude of 30.1 ± 4.6°N at ca. 222 Ma. When combined with existing paleomagnetic constraints, these new results indicate that the South Qiangtang block (and other “Cimmerian” blocks) moved rapidly northward (in true latitude) between the middle Permian and Late Triassic. Our new data further suggest that the southern branch of the Paleo‐Tethys (Longmuco‐Shuanghu Ocean) likely closed by the mid‐Late Triassic.
10 May 2020 in Journal of Geophysical Research: Solid Earth
This paper presents a quantitative characterization of the early Permian latitude and longitude of the Tarim block and its relationship to the supercontinent Pangea using a combination of newly acquired paleomagnetic data and inferences drawn from the plume generation zone reconstruction method. Early Permian magmatic rocks from Tarim have previously been interpreted as constituents of a large igneous province (LIP) and were therefore possibly derived from a mantle plume originating at the core‐mantle boundary. Here, we present the results of a paleomagnetic investigation of early Permian rocks (~288 Ma) in the Keping area of northwestern Tarim. A stable high‐temperature component (HTC) was isolated from 413 samples from 51 sites. The directions of this HTC pass the fold test and are of exclusively reversed polarity, which is consistent with their acquisition during the late Carboniferous to mid‐Permian Kiaman Reverse Polarity Superchron, suggesting that the HTC is likely primary. From these results, we compute a new early Permian pole for Tarim: 50.1°N, 170.5°E, A95 = 3.6°. Taking the estimated eruption center of the Tarim LIP (41°N, 80°E) as a reference point, this pole restores the LIP to a paleolatitude of ~30° at 288 Ma. Given this paleolatitude estimate, we attempt to fit the LIP to the edge of one of the large low shear velocity provinces in the lowermost mantle. It is not feasible to reconstruct the Tarim LIP directly above the margins of either the African or Pacific large low shear velocity provinces, but its reconstructed position could potentially be associated with the “Perm” anomaly.
17 May 2025 in Earth and Planetary Science Letters
The absence of reliable paleomagnetic constraints from the Lhasa Block has led to alternative interpretations of its late Paleozoic position and timing of rifting from Gondwana, reflecting uncertainties in early Neo‐Tethyan paleogeography. This study presents paleomagnetic and geochronological data from the middle Permian Luobadui Formation, providing a new paleogeographic constraint on the Lhasa Block. Despite possible remagnetization, the dual‐polarity magnetization, hosted in different minerals and lithologies, likely represents a middle Permian remanence. This constraint implies the Lhasa Block was located at 16.7 ± 5.3°S at 267.8 ± 5 Ma, following its rifting from Gondwana. New U‐Pb detrital zircon ages from sandstones further suggest the Lhasa Block was located along the northwestern margin of Australia prior to rifting. Integrating other geological evidence, we propose that the Bangong Co‐Nujiang and Yarlung‐Zangbo oceans, now preserved as sutures flanking the Lhasa Block, both opened before the middle Permian, potentially representing branches of the same nascent oceanic corridor (Neo‐Tethys).