The Qinghai-Tibet Plateau comprises a mosaic of geologically distinct Paleozoic and Mesozoic blocks, including the Qaidam block, Songpan-Ganzi block, Qiangtang block(s), Lhasa block and Himalayan block (Figure 1a). It is generally acknowledged that some of these blocks originated from the northern margin of Gondwana, splitting from it in the Carboniferous or Permian before subsequently drifting northward to collide with Laurasia in the
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.
Understanding of the geodynamic evolution of the Tethyan realm cannot be complete without paleogeographical reconstructions of the North Qiangtang Block (NQB) that occupies a central position in Tibet. However, the reliability of such a reconstruction for the Paleozoic still requires substantial improvement. In this paper, we present paleomagnetic results obtained from the Middle Permian limestones and Upper Permian volcanic rocks in the Tanggula area, aiming to provide precise constraints on the NQB kinematics during the geodynamic evolution of the Tethys realm. Combined with other available paleomagnetic data from the NQB, our results suggest that the block was stably located at ∼24°S for a long time before the Middle Permian, started to drift rapidly northward in the Middle Permian, and reached ∼8.4°S in the Late Permian. The NQB continued drifting rapidly northward during the Triassic until merging with the southern margin of Eurasia in the Late Triassic. We reviewed new and available paleomagnetic and geological data and proposed a revised model for the tectonic evolution of the eastern Tethys realm. The NQB likely belonged to a ribbon-like separate continental archipelago in the middle of the Paleo-Tethys Ocean during the early−late Paleozoic. The Cimmerian continent, including the South Qiangtang Block (SQB), rifted away from the northern margin of Gondwana and drifted northward to ∼22°S in the Middle Permian. The continent approached or partially collided with the NQB, resulting in the rapid northward movement of the NQB and the formation of the Longmuco−Shuanghu suture between the NQB and SQB.
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