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The India-Eurasia collision zone represents one of the most tectonically active regions of Earth, and the present-day kinematics has been largely documented (after Allègre et al., 1984;Armijo et al., 1986Armijo et al., , 1989Molnar et al., 1973) by geologic, seismologic, and geodetic datasets. The GPS velocity field (Figure 1) shows that at present the E Tibet crust flows eastward quasi-continuously, mostly channelizing towards Indochina, between the rigid crust buttresses of Sichuan Basin and East Himalayan Syntaxis (hereinafter EHS;Clark & Royden, 2000;Ge et al., 2015;Gan et al., 2021). The evolution of the Himalayan-Tibet orogen during the geologic past has been addressed by geologic and tectonic data from regional shear zones, thrust fronts, and sedimentary basins from Tibet-Indochina. Tapponnier et al. (1982Tapponnier et al. ( , 1990 suggested that the Oligo-Miocene (∼30-20 Ma) India-Asia collision was accommodated by E-SE directed extrusion of few "mega-blocks" (or microplates), bounded by continental-scale strike-slip (or transform) faults with lateral offsets of about 1,000 km. However, the geologic offset of some of those major strike-slip faults, such as the Ailao Shan-Red River shear zone (Figure 1), was later defined as impossible to determine on geologic grounds (Searle, 2006), or paleomagnetically related to much smaller values (Li, Advokaat, et al., 2017;Speranza et al., 2019). Thus, the tectonics of Tibet and Indochina during the Cenozoic (i.e., the last 60 Ma) is still debated, as it is unclear if and when tectonism turned into the present-day style characterized by diffuse deformation crust and eastward Tibet drift.Paleomagnetism often is an important tool to assess tectonic styles during the geologic past, as it provides estimates of total vertical-axis rotations of crustal sites, thus identifying the pattern of blocks into which the crust is broken and the kinematics of such blocks. A wealth of paleomagnetic data-mostly from Indochina Jurassic-Oligocene

Existing models describing continental crust deformation require the coexistence of strike‐slip faults and crustal blocks rotating between them, although the dimension and shape of the blocks and the location and offset of the faults are mostly unconstrained. Here we report on the paleomagnetism of middle Cenozoic (<45 Ma) continental red beds exposed along the 40 km long and 2–8 km wide NW‐trending Mula basin (East Tibet), unconformably lying above Triassic marine strata and plutons and mildly deformed by two subparallel thrust faults. A tectonic magnetic fabric and magnetic lineations subhorizontal and parallel to the compressive fronts show that thrust tectonics guided basin formation and continued soon after sediment deposition. Characteristic and high‐temperature components isolated at 17 sites support a positive fold test and suggest primary detrital magnetization acquisition. The comparison with East Asia paleopoles defines several 2–5 km wide crust fragments yielding variable rotations from ~30° counterclockwise to ~90° clockwise without clear rotation trend. No strike‐slip fault with offset exceeding 1 km occurs among blocks, and no regional‐scale strike‐slip fault is documented at basin vicinity, implying that the East Tibet rotation pattern is different from all existing block rotation models. A regional high thermal flow and vigorous geothermal activity are consistent with the occurrence of a ductile crust layer identified by seismological data at 13–30 km depths. We suggest that midlower crust, flowing SE‐ward toward Indochina, drag upper crust fragments that were randomly rotated depending on the local torque exerted on lower block boundaries by a ductile crust flow.