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The identification of the Grenvillian‐age ophiolite suites in the Yangtze block in recent years suggested that the northern Yangtze subblock (NYB) and the southern Yangtze subblock (SYB) were once separated by an ocean in late Mesoproterozoic. Although some paleogeographic models advocated the Pre‐Grenvillian connections between the south China blocks and Laurentia, none of them has been paleomagnetically tested. Here we report the new paleomagnetic results obtained from the ∼1,270 Ma purplish‐red muddy dolomite beds of the Luanshigou Formation, Shennongjia Group, NYB, providing new constraints for reconstructing the paleogeographic positions of the south China blocks in late Mesoproterozoic. A total of 447 samples underwent stepwise thermal demagnetization. Two components were identified. The low‐temperature component is interpreted as the recent viscous remnant magnetization. The high‐temperature component was obtained from 64 samples below 580°C and from 177 samples below 690°C, directed northeast‐up or southwest‐down, antipodally, positioning the paleomagnetic pole at 18.5°S, 74.4°E (dm/dp = 2.5/1.6°). Rock magnetic results demonstrate that the magnetic carriers in purplish‐red dolomite and pale‐pink dolomite are predominated by hematite and magnetite, respectively. The data quality is supported by an inverse baked contact test, a B‐class reversal test, and the paleomagnetic pole is distinct from any younger poles of the region. Based on the paleomagnetic results, aided by geological evidence, we propose a reconstruction in which the NYB was juxtaposed to southwestern Laurentia in the late Mesoproterozoic and suggest that the late Mesoproterozoic Miaowan‐Shimian ophiolite zone in the Yangtze block was likely an extension of the Grenville belt of Laurentia. Plain Language Summary: The south China block was traditionally subdivided into the Yangtze block to the northwest and the Cathaysia block to the southeast, which were separated by an early Neoproterozoic ocean. Recently published geological data further suggest that the Yangtze block contains two subblocks, the NYB and the SYB, which were separated by a late Mesoproterozoic ocean. Several paleogeographic models proposed the Mesoproterozoic relationships between the south China blocks and Laurentia, but none has been paleomagnetically tested. Here we report a new paleomagnetic pole obtained from the ∼1,270 Ma purplish‐red dolomite beds of the Luanshigou Formation, Shennongjia Group in the NYB. The data quality is assured by the positive paleomagnetic field tests. Our results combing with the geological evidence suggest that the NYB was located in a low‐latitudinal position and connected to southwestern Laurentia in the late Mesoproterozoic. The late Mesoproterozoic ophiolite zone in the southern margin of the NYB was likely an extension of the Grenville belt. Key Points: A new paleomagnetic pole (18.5°S, 74.4°E, dm/dp = 2.5/1.6°) was obtained from the late Mesoproterozoic Luanshigou Formation of the Shennongjia Group in south ChinaThe northern Yangtze subblock (NYB) was connected to southwestern Laurentia at the late MesoproterozoicThe late Mesoproterozoic Miaowan‐Shimian suture zone in the southern margin of the NYB was likely an extension of the Grenvillian orogenic belt [ABSTRACT FROM AUTHOR]

The timing of formation of the Hegenshan suture is crucial to understanding the evolution of the Central Asian Orogenic Belt (CAOB). Here we present a well‐dated paleomagnetic pole (103 samples from 15 sites, 36.7°N/29.2°E, A95 = 3.3°) that passed a positive fold test, a reversal test, and a conglomerate test from the ∼250 Ma upper Gunbayn Formation andesites in the southeastern Mongolia Block (MOB). The high‐quality paleomagnetic database may demonstrate that the MOB drifted rapidly southward and collided with the Xilinhot–Songliao Block between 256 and 250 Ma, resulting in the closure of the Hegenshan Ocean at ∼250 Ma. The Hegenshan suture and the Solonker suture were formed almost simultaneously and marked the final closure of the Paleo‐Asian Ocean. Plain Language Summary: The Central Asian Orogenic Belt (CAOB) is the largest accretionary orogenic belt on earth since begin of the Phanerozoic. Since the Late Paleozoic, two prominent sutures, namely the Hegenshan and Solonker sutures, have played crucial roles in the tectonic evolution of the eastern CAOB, as they were associated with the closure of the Paleo‐Asian Ocean (PAO). The timing of the formation of the Hegenshan suture, however, remains ambiguous due to the lack of reliable paleomagnetic data. In this study, we present accurately dated paleomagnetic constraints on the paleogeographic position of the Mongolia Block (MOB), located on the northern side of the Hegenshan suture, at ∼250 Ma. By combining high‐quality Late Permian–Early Triassic paleomagnetic data with geological evidence, we propose a new reconstruction that suggests the near‐simultaneous closure of both the Hegenshan and Solonker oceans around 250 Ma. This significant event marks the final disappearance of the PAO and represents a fundamental stage in the establishment of the tectonic framework of the eastern CAOB at that time. Key Points: We report a well‐dated ∼250 Ma paleomagnetic pole from the Mongolia BlockThe closure of both the Hegenshan and Solonker oceans at ∼250 Ma marked the final disappearance of the Paleo‐Asian Ocean [ABSTRACT FROM AUTHOR]

The timing and location India–Asia collision is crucial to understanding the evolution of the Himalayan–Tibetan orogen and global climate change; however, estimates of the timing of the India–Asia collision and the size of Greater India remain highly controversial. We report here the first reliable early Eocene paleomagnetic results from the Zhepure Formation limestone in the Tethyan Himalaya (TH). Both positive fold and reversal tests indicate a primary origin. The tilt‐corrected site‐mean direction is Ds = 332.6°, Is = 20.1°, ks = 90.9, α95 = 2.8° (N = 30). The site‐mean inclination increased from 20.1° to 27.5° after inclination shallowing correction, yielding a paleopole at 61.2°N, 337.3°E, A95 = 2.6° and a corresponding paleolatitude of 15.2° ± 2.6°N for the reference point (29.5°N, 91.0°E). Our new paleomagnetic results, together with the reliable Cretaceous to Paleogene paleomagnetic results from the TH, Lhasa terrane and Indian craton, suggest that there was ∼900–1,140 km north‐south crustal shortening occurred between the TH and the Indian craton, and that India collided with Asia at no later than ∼51–49.5 Ma. Plain Language Summary: The India–Asia collision is among the most intriguing topics in earth sciences because of its influence on global climate and Cenozoic topography. However, several questions still remain unanswered, such as: how big was Greater India? When, where, and how did the India collide with Asia? We report the first reliable early Eocene paleopole from the TH and assess the timing of the India–Asia collision and the size of Greater India. Our results suggest a relatively small Greater India, and that India collided with Asia at no later than ∼51–49.5 Ma. The constraints on the India–Asia collision indicated by our data provide new boundary conditions for the history of the Himalayan–Tibetan orogen and global climate change. Key Points: The Tethyan Himalaya (TH) was located at 15.2° ± 2.6°N at ∼51–49.5 MaThere was ∼900–1,140 km north‐south crustal shortening occurred between the TH and the Indian cratonIndia collided with Asia at no later than ∼51–49.5 Ma [ABSTRACT FROM AUTHOR]

To better constrain the origin and drift history of the North Qiangtang terrane (NQT), we report a well‐dated paleomagnetic pole from the Late Permian volcanics of the NQT that appears to average out secular variation. Our new results yield a paleolatitude of −7.6 ± 5.6°N at ~259 Ma for our sampling area, which confirms the NQT drifted northward during the Permian and Triassic periods. The equatorial paleolatitude of the NQT is similar to that of the coeval South China block, demonstrating that they were in close proximity. Combined with palaeontological and magmatic evidence, paleomagnetic constraints on the drift of the NQT in the Permian indicate that the NQT moved northward together with the South China block at this time. The paleolatitude evolution of the NQT implies that the NQT rifted from the northern margin of the Gondwana in the Devonian, which is earlier than the departure time of the South Qiangtang terrane. Plain Language Summary: The Tibetan Plateau is composed of several different blocks that accreted to the southern margin of Asia. There are still several unanswered questions, such as the following: Where did these blocks originate? How did these blocks accrete to Asia? How did the oceanic basin evolve? In this work, we provide robust evidence to show that the Northern Qiangtang was located at equatorial latitude (−7.6 ± 5.6°N) during the Late Permian (~259 Ma). The northward drift history together with features of the Northern Qiangtang and South China block indicates that they moved northward together during the Permian and that the Northern Qiangtang rifted from the northern margin of the Greater India margin of Gondwana during the Devonian. Key Points: The North Qiangtang terrane (NQT) was located at equatorial paleolatitude (−7.6 ± 5.6°N) during the Late Permian (~259 Ma)The NQT drifted northward together with the South China block (SCB) during the PermianThe NQT rifted from the northern margin of Gondwana during the Devonian [ABSTRACT FROM AUTHOR]

The Cryogenian nonglacial epoch (CNE) spans from the termination of the Sturtian snowball Earth (ca. 659 Ma) to the initiation of the Marinoan snowball Earth (ca. 649.2 Ma). The carbonate sequences formed in low latitudes record paleoclimatic and paleoceanographic changes during the CNE. Three negative carbon isotope (δ13C) excursions, named Rasthof, Tayshir and Trezona, are present at the bottom, middle, and top of the carbonate sequences, bracketing two intervals with highly positive δ13C values. Uranium isotope (δ238U) data from Mongolia reveal ocean redox changes linked to δ13C variations during the CNE, marked by the development of anoxic deep ocean to extensive oxygenation and subsequent deoxygenation. However, the timing and duration of these paleoceanographic events and δ13C excursions have not been adequately investigated. Here, we report new environmental magnetic results of the higher paleo-latitudinal, siliciclastic-dominated Datangpo Formation (Fm) in South China that may help constrain the age and correlation of the CNE geochemical events. We identified four segments of the Datangpo Fm based on the magnetic susceptibility (MS) profile and other environmental magnetic parameters, which are, in ascending order, the ascent segment (Da), lower stable-segment (Db), transition segment (Dc), and upper stable-segment (Dd). These segments are dated by the astronomical time scale as 659–655.6 Ma (Da), 655.6–653.3 Ma (Db), 653.3–652.3 Ma (Dc), and 652.3–649.2 Ma (Dd). Environmental magnetism analyses show that the highest magnetite concentration but lowest fine-grained magnetite contents are present in "Da", followed by "Dd" and "Db". These results suggest a sea-level fall and a potential decrease in oxygenation after the deposition of the transition segment (Dc), implying that a cooling climate started ∼4 Myr before the Nantuo glaciation (Marinoan snowball Earth). Ocean redox variations revealed by environmental magnetism in the Datangpo Fm are consistent with those reported from the low-latitudinal carbonate sequences. "Da" likely corresponds to the Rasthof δ13C excursion and "Dc" corresponds to the Tayshir δ 13C excursion; whereas "Db" and "Dd" probably correspond to the two intervals with positive δ 13C values. • Four segments of the Cryogenian nonglaciatial epoch in South China are identified and the time of each segment is constrained. • Environmental magnetism analyses show a climate cooling ∼4 Myr before the Nantuo glaciation (or Marinoan snowball Earth). • Siliciclastic depositions in South China are linked to carbonate depositions in low-latitude continents. [ABSTRACT FROM AUTHOR]

Abstract: The Solonker suture zone is one of the most important tectonic boundaries in the southeastern part of the Central Asian Orogenic Belt (CAOB). An ~630km-long reflection seismic profile across this suture was recently completed by the Chinese SinoProbe Project. The processed seismic data show clear crustal structures and provide new constraints on the tectonic and crustal evolution models. The Moho is delineated as a relatively flat boundary between a strongly reflective lower crust and a transparent mantle at a depth of ~40–45km (~14.5s two-way travel time), which is in agreement with the refraction data recorded along the same profile. In a broad view, the profile images an orogen that appears bivergent with, and approximately centered on, the Solonker suture zone. The southern portion of this profile is dominated by a crustal-scale, cratonward propagating fold-and-thrust system that formed during the late Permian and Triassic through collision and subsequent convergence in a post-collisional stage. The major thrust faults are truncated by Mesozoic granitoid plutons in the upper crust and by the Moho at the base of the crust. This geometry suggests that the Moho was formed after the thrusting event. The northern portion of the profile, although partially obliterated by post-collisional magmatic bodies, shows major south-dipping folding and thrusting. Bands of layered reflectors immediately overlying the Moho are interpreted as basaltic sills derived from the mantle. Episodic mafic underplating may have occurred in this region, giving rise to post-collisional magmatic events and renewal of the Moho. A few mantle reflectors are also visible. The overall geometry of these mantle reflectors supports the tectonic models that the southern orogen (Manchurides) experienced south-directed subduction and the northern orogen (Altaids) underwent north-directed subduction prior to collision along the Solonker suture zone. [Copyright &y& Elsevier]