The assembly and dispersal of the Columbia supercontinent record the earliest collisional orogenic cycle on Earth. Syn- and post-collisional magmatism provides critical insights into key orogenic processes, including the timing and crustal evolution of orogenic belts from continental collision to orogenic root detachment and collapse. This study investigates adakitic rocks, A-type igneous complexes, and mafic dykes in the Yinshan Block of the North China Craton, with zircon U-Pb ages ranging from 1890 Ma to 1663 Ma. The adakitic rocks, formed between 1890 and 1875 Ma, indicating partial melting of thickened Neoarchean mafic lower crust. The A-type complex comprises gabbro, diorite, and granite, with zircon U-Pb ages of 1827-1692 Ma. Geochemical classification of A(2) subgroup implies post-collisional extensional melting of the metasomatized mantle. Two distinct types of mafic dykes are identified. Type I mafic dykes are older (similar to 1860-1848 Ma), subalkaline, and display relatively high MgO and Mg#, along with negative epsilon Nd(t) values, suggesting derivation from high-degree melting of metasomatized lithospheric mantle during the early stages of orogenic unrooting, driven by thermal erosion from upwelling asthenosphere. In contrast, Type II dykes are younger (1663 Ma) and spatially and genetically associated with the A-type complex. They are alkaline and exhibit elevated trace element concentrations, but have low MgO (Mg#), Cr, and Ni, indicative of low-degree melting of metasomatized lithospheric mantle during mantle delamination. After the final assembly of the Columbia supercontinent, post-collisional extension in the Yinshan Block followed terminal compression at approximately 1860 Ma. Orogenic collapse triggered asthenospheric upwelling, leading to melting of the metasomatized lithospheric mantle and the generation of A-type granites and alkaline mafic dykes. This thermo-mechanical weakening likely culminated in lithospheric delamination, with the dense lithospheric root foundering at around 1663 Ma. This geodynamic process drove mountain belt collapse and basin development and ultimately contributed to cratonic stabilization, marking the onset of the quiescent interval known as the Boring Billion.

Recent observations have challenged the traditional view that most continental lithosphere remains largely stable and maintains its primary structure following formation. It is now evident that in both convergent systems and mantle plume settings, continental lithosphere can be extensively destructed. This occurs through mechanical deformation or melt-rock interaction, leading to processes such as delamination or dripping of the lower lithospheric mantle. In this work, we focus on the convergent systems along the Tethyan Belt to examine the specific modes of continental lithosphere destruction and the factors or settings that govern the evolution of continental deformation.As a weak overriding continent, the Central Iran Block has been greatly reworked by the collision between the Arabia and Eurasia, resulting in a nascent orogenic plateau. Through this process, continental deformation is initially localized within weak zones-the Alborz and Zagros belts-before gradually becoming more homogeneous to form a small, low-altitude plateau.Acting as a rigid overriding continent, the South China Block underwent a protracted subduction of the Paleo-Pacific Plate, which triggered cyclical contraction and extension events in the Mesozoic. Within a single cycle, compression weakens the east margin of the thick continental lithosphere beneath the western South China Block; subsequent extension then destructs this part, leaving a thinned lithosphere. This progressive destruction model illustrates how a rigid continent responds to a continuous subduction setting.Another example of a rigid overriding continent is the east North China Craton. Unlike South China, this region was modified during the Triassic continent collision. During this event, continent subduction bulldozed the lithosphere mantle and low crust of North China and then rebuilt it with materials of the subducting plate.In summary, the process of continent destruction depends on the structure of the overriding plate and the stage of convergence (subduction vs. collision).(1) Intensity of destruction: Continental destruction is generally more intense during collision than during subduction.(2) Stress distribution: Stress tends to be localized during the early stages of continental destruction but gradually becomes more homogenized as collision progresses.(3) Rigid continent dynamics: In rigid continents, destruction typically initiates at the border of the lithospheric root via delamination or dripping. Within episodic subduction/collision systems, this destruction can become cyclical, significantly reducing the overall size of the rigid continental lithosphere.

The Talesh-Alborz Belt in northern Iran records the Paleo-Tethys Ocean closure and subsequent continental collision between Central Iran and Eurasia. However, the timing and kinematics of collision along the western Alborz remain poorly constrained. Here, we present new LA-ICP-MS zircon U-Pb geochronological data analysis and quantitative provenance modeling on Paleozoic to Early Mesozoic metasedimentary rocks of the Rasht region to reveal the provenance change before and after the collision. Zircon age spectra from four clastic samples reveal three major age populations: Paleoproterozoic (2.1–1.8 Ga) and Late Paleozoic (450–250 Ma) age groups with Eurasian affinity, alongside a Neoproterozoic-Early Paleozoic (1000–500 Ma) population linked to Gondwanan (Central Iran) source. Sample AB438 from the Masuleh-Shah Rud unit exhibits a distinctly Eurasian-affiliated Turan sources and yields a youngest zircon of 226 ± 2 Ma, in marked contrast to the Gondwana-related Pan-African/Cadomian sources from the other three samples. This study provides the first robust geochronologic constraint on the onset of collision in the western Alborz, dated to approximately 226 Ma. Compared with the Central and East Alborz, synchronous Paleo-Tethys closure and continental collision occurred nearly along the entire Alborz. Our results refine the spatiotemporal framework of the Cimmerian orogeny and provide tighter constraints for geodynamic models of the evolution for the Central Neo-Tethys.

Emergent continental crust is important for the evolution of Earth's surface system and the development of habitability, and it is apparent that early Archean cratons were locally emerged. However, it remains unresolved if the North China Craton, which preserves ancient (4.1-4.0 Ga) crustal remnants, had emergent continental crust during the early Archean. Here, we report geochronological and geochemical data on Paleo-Mesoarchean potassic granites in Eastern Hebei, within the North China Craton, to determine whether or not there was any early Archean exposed landmass in this craton. We constrain that the studied potassic granites formed at ca. 3.2 Ga, and their bulk-rock and zircon Hf isotopic geochemistry reveals that they were produced by anatexis of Paleoarchean tonalite-trondhjemite-granodiorite (TTG) crust. Their low zircon delta 18O values should have been inherited from their Paleoarchean TTG source, and 18O-depletion of this Paleoarchean TTG source was achieved through high-temperature hydrothermal alteration with the infiltration of isotopically light meteoric water into the shallow crust, prior to the ca. 3.2 Ga anatexis. The identification of Paleoarchean TTG crust altered by meteoric water in Eastern Hebei indicates the emergence of continental crust in the North China Craton during 3.6-3.2 Ga, and this Paleoarchean continental emergence could have been associated with magmatic underplating during mantle plume activities, which is also evidenced by the Paleoarchean enriched plume remnants in Eastern Hebei.

The Neoarchean (2.8-2.5 Ga) represents a critical transition towards a habitable Earth. Gradual development of plate subduction during this era facilitated crustal differentiation and maturation, reflected by compositional changes of the Archean continental crust. However, key physical properties of Neoarchean crust-building felsic magmas, such as oxygen fugacity (fO2) and water content, remain loosely constrained. Here we show that ca. 2.5 Ga granitoids in the North China Craton are considerably oxidized and hydrous, and comparable to modern arc magmas. Their elevated fO2 and water content (Delta FMQ-1.0 to 2.8, 5.7-16.6 wt% H2O; average at Delta FMQ +0.8 and 9.6 wt% H2O) are attributed to fluids released from the subducting oceanic crust, which metasomatized the mantle wedge. Such slab-derived fluids facilitated the generation of Neoarchean oxidized and hydrous felsic magmas through water-fluxed melting of the underplated mafic crust derived from the metasomatized mantle wedge, accompanied by various redox reactions and volatile incorporation. Our work demonstrates that localized synchronous oxidation and extensive fluid circulation across Earth's reservoirs driven by plate subduction likely occurred in some cratons at the end of the Archean.

Subduction advance or retreat results in an erosional or accretional plate boundary, and strong orogen-parallel heterogeneity in large suture zones, but their identification of these processes is challenging. Blueschist is a proxy that can archive these tectonic processes in ancient subduction zones. Within NW T & uuml;rkiye, the Tav & scedil;anl & imath; zone preserves blueschist-facies rocks, and documents a succession of subduction events that preceded the closure of the Neo-Tethys Ocean. Here, we report for the first time the occurrence of Triassic blueschist blocks within the Late Cretaceous Tav & scedil;anl & imath; zone. These blueschists and marbles have abundant HP minerals such as winchite, jadeite, and lawsonite, and yield zircon U-Pb age at ca. 228 Ma, resembling the Karakaya HP metamorphic rocks of the overlying Eurasian plate. The available block-matrix relationships record strong later deformation, but do not preserve the diagnostic textures required to determine whether the Triassic rocks were incorporated into the younger complex by tectonic or sedimentary processes. Regionally, the extensive low-angle geometry of the & Idot;zmir-Ankara-Erzincan suture, the scarcity of Jurassic-Early Cretaceous arc and ophiolitic remnants, the landward migration of the magmatic arc front, and provenance links between the Tav & scedil;anl & imath; and Sakarya zones, are compatible with significant forearc removal during Neo-Tethys evolution. In this context, the Triassic HP rocks may have been either redeposited into trench-fill deposits and resubducted, or tectonically entrained along the erosive plate interface and accreted downdip. These results highlight the importance of multi-stage tectonic reworking in assembling age-disparate HP terranes along the Tethyan suture system.

The evolution of continental rifts is influenced by the pre-rift rheology of the lithosphere and discrete lithospheric structures that segment the rift. The Great South Basin, offshore New Zealand, is a Cretaceous rift system that formed across heterogenous basement terranes which influence the rift architecture. Faults locally rotate or splay and segment along these terrane boundaries. While the impact of terrane boundaries on rift architecture is well understood, the temporal evolution of these rotated faults is poorly constrained. Here we use 3D reflection seismic data to investigate the timing and slip rate evolution of the rotated and segmented faults along two terrane boundaries. Our results show that these have a significant but variable impact on rift evolution and architecture: Faults in the Murihiku terrane show asymmetric throw-length profiles and are rotated along the terrane boundary to the Dun Mountain-Maitai terrane, as they detach into shallow crustal fabrics. Faults in the DMM terrane show less evidence of rotation and more symmetric throw-length profiles but are segmented along the DMM and Caples terrane boundary. The curving faults of the Murihiku terrane likely formed early on but remained as isolated segments only linking up during later stages of rifting when other faults became inactive. These results show the influence of the terrane boundaries was not only active early during initial segmentation but also during the linkage of curved fault segments in the later stages of rifting. These results may help understand the temporal evolution of lithospheric and crustal inheritance on rift evolution in other regions around the world like East Africa or North China.

The Tibetan and Iranian plateaus are the two most prominent orogenic plateaus on the present Earth built by continental collision. However, the timings of initial collision and suturing in the Himalaya and Zagros remain debated. In this Review, we summarize the timings, similarities and differences between the India–Eurasia collision and the Arabia–Eurasia collision, by comparing their sedimentary, magmatic, metamorphic, structural and palaeomagnetic records. The India–Eurasia collision is tightly constrained to have initiated in the central Himalaya at 65–59 Ma, possibly progressing towards the western and eastern Himalayas by 55–50 Ma. By contrast, the initial collision in the Zagros is loosely constrained to ~34 Ma, with a possibility of diachronous collision, younging to the southeast. Similarities between the two collisions include pre-collisional accretionary tectonism and magmatism, syn-collisional deformation and sedimentation, and crustal thickening. Apparent differences in lithospheric dynamics, deformation styles and metamorphism are attributed to variations in convergence rates, durations and magnitudes. Future research should focus on data-driven modelling and geophysical imaging beneath the Tibetan and Iranian plateaus to further quantify the geodynamic processes and driving forces contributing to continuous plate convergence, plateau formation and their surface impacts. The collision of the Indian, Arabian and Eurasian plates formed the Tibetan and Iranian plateaus, but its timing and processes remain debated. This Review explores the evidence behind initial collision estimates and discusses the tectonic and geodynamic implications.

Tectonic transitions from compression to extension at an active continental margin provide clues for a better understanding of the geodynamics of plate subduction. Here, we present detailed investigations of Jurassic to Cretaceous dike swarms in the east margin of the North China Craton (NCC). It is demonstrated that the Jurassic dikes are distinctly different from the Cretaceous dikes, in terms of both occurrence and geochemistry. The Jurassic dike swarms, which include both mafic and felsic types, all strike in NW-dominated directions. Most Jurassic felsic dike swarms display adakitic geochemical characteristics, interpreted to be formed by melting of the ancient lower crust of the NCC. Jurassic mafic dike swarms originated from the metasomatic enriched lithospheric mantle. Thus, the Jurassic dike swarms are indicative of a compressional environment. However, the Cretaceous dike swarms strike in NE-dominated directions. The Cretaceous felsic dike swarms are characterized by geochemical features of A-type granites. The Cretaceous mafic dike swarms have originated from the asthenospheric mantle during back-arc extension. We propose that the Jurassic crustal thickening, lower crustal reworking, and the melting of ancient lithospheric mantle are the result of the Paleo-Pacific subduction and related compression. In contrast, crustal thinning indicated by the orientation of Cretaceous dike swarms and their high-temperature features, as well as the reworking of the upper and middle crust and the appearance of depleted mantle, are the result of extension caused by the rollback of the Paleo-Pacific Plate. Variations of composition and orientation of dike swarms effectively reflect the tectonic transition from compression in the Jurassic to extension in the Cretaceous along the east margin of the NCC.

Subduction initiation is a strongly debated subject in tectonics. Reconstructions of some ancient plate margins involve the propagation of subduction from a different oceanic plate in a process known as invasion or infection. A difficulty in recognizing ancient subduction invasion is that it may not leave a distinctive record. This paper proposes that Permian initiation of Paleo-Pacific Plate subduction along the East Asian margin was linked to the closure of similar to east-west-trending oceans during the assembly of the Asian continent, including branches of the Paleo-Tethys Ocean and the Paleo-Asian Ocean. There are circumstantial indications of subduction invasion in the orientations and relative timings of subduction systems in the region. Further evidence comes from the Indian/Tethyan Ocean Dupal isotopic signature of some western Pacific basalts, dating as far back as the Permian. We suggest that this Dupal signature was first transferred during Tethyan Ocean closure in the Permian-Triassic, and from a relatively shallow source.

Paleo-Pacific subduction significantly impacted the structure and nature of the mantle in Eastern China. However, the thermal structure of the supra-subduction-zone mantle during the early stage of the Paleo-Pacific subduction has not been well constrained. Here, we present an integrated study involving field investigation, petrology, and geochemistry on two types of Jurassic (168-155 Ma) mafic dyke swarms in Western Liaoning, North China Craton (NCC), to trace the properties of the NCC mantle during the Jurassic. The picritic dyke swarms, trending NNW (330 degrees-350 degrees), show OIB-like geochemical signatures, with high mantle potential temperatures (Tp) ranging from 1498 f 52 degrees C to 1535 f 56 degrees C. These picritic dyke swarms are derived from high- degree of partial melting of the asthenospheric mantle by a hot and hydrous asthenospheric melts rising from the mantle transition zone above the subducted slab. In contrast, the Jurassic potassic mafic dyke swarms, trending NNW (325 degrees-345 degrees), were formed by partial melting of the metasomatized lithospheric mantle during the upwelling of the asthenospheric melts. We conclude that thermal erosion would be a major factor in the destruction of the lithospheric mantle beneath the NCC in the early stage of the Paleo-Pacific plate subduction.

Mantle plumes from deep Earth's interior play a significant role in mantle convection and plate tectonics.Their impact on oceanic lithosphere is invoked to initiate oceanic subduction and modern plate tectonics in the early Earth.They may also contribute to the rifting and break-up of continents and follow oceanic spreading to form open ocean basins during the early stage of the Wilson cycle in the Phanerozoic[1,2].In present-day ocean basins,long-lived mantle plume activities coupled with plate motions are sup-posed to leave spectacular age-progressive trails of intraplate mag-matism,such as the 6000-km Emperor-Hawaiian volcanic seamount chain across the Pacific plate.These intraplate igneous rocks provide valuable insights into plate motions,mantle convec-tion,and geochemical recycling.For example,hotspot trails of Tris-tan-Gough in the Southern Atlantic have recorded a complete history of the opening of the Atlantic Ocean[3].

In the Paleozoic, the Alxa Block was situated between the Central Asian Orogenic Belt and the North Qilian Orogenic Belt, and it experienced intense magmatic activity. Thus, the Alxa Block is an important area for understanding the tectonic framework and evolution of these two orogenic belts. However, there has long been debate regarding the tectonic affinity and tectonic evolution of the Longshoushan, located in the southwestern margin of the Alxa Block, during the Paleozoic. In this study, we present zircon U–Pb ages, whole-rock major and trace elements, and Hf isotopic data for the granitoids from the east of the Longshoushan to investigate these issues. Bulk-rock analyses show that these granitoids are weakly peraluminous, with high SiO2 and K2O but low MgO, TFe2O3, and P2O5. They are also characterized by enrichment in LREE and LILE, depletion in HREE and HFSE, and a large range of εHf(t) values (monzogranite: −0.3 to −16.2; K-feldspar granite: 3.5 to −7.7). These geochemical features indicate that these granitoids are highly fractionated I-type granites, which were formed by crust- and mantle-derived magma mixing. LA-ICP-MS zircon U–Pb dating constrains the monzogranite and K-feldspar granite formed at 440.8 ± 2.1 Ma and 439.4 ± 2.0 Ma, respectively. Combining these results with previous chronological data, the geochronology framework of Paleozoic magmatic events in the Longshoushan is consistent with the North Qilian Orogenic Belt to the south but significantly differs from other parts of the Alxa Block and the Central Asian Orogenic Belt to the north. This result indicates that the Longshoushan was primarily influenced by the North Qilian Orogenic Belt during the early Paleozoic. Integrated with previous studies, a three-stage tectonic model is proposed of early Paleozoic accretion and arc magmatism leading to collision in the Longshoushan: (1) arc magmatism on an active continental margin with the northward subduction of the North Qilian back-arc basins (NQ bab; 460–445 Ma); (2) magmatic rocks, dominated by I-type granites, forming in a continent–continent collision setting, with significant crustal thickening interpreted as resulting from compressional stress and/or magmatic additions (445–435 Ma); (3) the development of abundant A-type granites and mafic dikes in response to extension, supported by a change in trace element chemistry indicating crustal thinning at this stage (435–410 Ma). This sequence of events and their timings is similar to other parts of the Central China Orogenic Belt and requires either a coincidence of several oceanic plates closing at the same time or an along-strike repetition of the same system.

Subduction zones are important for oxygen cycling between deep and surficial Earth reservoirs. Highly oxidizing materials from Earth's surface may be transported to the mantle along with the subducting slabs and alter the redox states of the mantle wedge and the 410-660 km transition zone. The circulation of oxygen or oxidizing fluids in subduction zones and how subducted materials influence the deep mantle are poorly constrained. Here we report growth of Fe-Mn garnet from highly oxidized pelagic ferromanganese chert within a high-pressure metamorphic complex in the Qilian Orogen, North West (NW) China. Two types of ferric-iron-rich garnets were identified. Type I is spessartine garnet that has clear compositional zonation of Al2O3-FeOt-MnO oscillatory growth. The Fe3+/∑Fe ratio in the core is as high as 1.0, but decreases to 0.1 in the outer rim, along with an increase of Fe2+ content and a significant decrease in Mn content. Type II is andradite-calderite garnet that contains extremely high Fe3+. Our results have two implications: (1) continuous reduction of Mn4+ (to Mn2+) and Fe3+ (to Fe2+) from the ferromanganese chert as garnet growth must be accompanied by releasing large quantity of oxygen or highly oxidized fluids during prograde high-pressure metamorphism in subduction zones, and (2) Fe3+-rich garnets together with hematite in the subducting slab can remain stable over a large pressure range, and provide an alternative interpretation for the high content of Fe3+ in the deep mantle. Our results are significant for understanding the oxygen recycling in oceanic cold subduction zones, and the initiation of the Great Oxygen Event (GOE) as well.

The Turkish–Iranian Plateau was formed by the collision between the Arabian andEurasian plates, commencing along the Bitlis-Zagros suture in the Late Eocene (~30-35 Ma). This region, commonly partitioned into the East Anatolian Plateau and theIranian Plateau, is associated with significant differences in terms of lithosphericstructure despite an overall average of ~2 km. The geodynamic evolution of EastAnatolia is represented by a double subduction system, where the two branches ofNeo-Tethys were subducting beneath Eurasia, constantly accumulating accretionarymaterial that forms the bulk of the plateau today (i.e., East Anatolian AccretionaryComplex). Seismic evidence demonstrates that the region has unusually thin MOHO(~35 km around Lake Van region) while the whole area is formed mostly by oceanic(accretionary) material and is underlain by no or very thin mantle lithosphere. Theuplift of East Anatolia is attributed to slab break-off and slab peelback (delamination),combined with crustal shortening. However, the intricate plate dynamics arising fromsuch a double subduction system, controlling plateau formation remains unclear.Here, we conducted 2D numerical experiments and comparative model sets indicatethat, in a double subduction system like Eastern Anatolia, the mechanisms of slabbreak-off and peelback heavily depend on the rheology of the subducting plates andthe coupling between the overlying and subducting plate along the trenches. In casesof strong coupling between subducting and overlying plates, we observed anamalgamation of the two subducting plates as they converge, potentially resulting ina break-off as a single blob, depending on plate rheology. Conversely, in models withweaker coupling along the trenches, peelback along the northern slab creates a thinlithosphere along the accretionary prism, such as in the evolution of the EasternAnatolian Plateau. Our results highlight the important interaction between thesubduction systems where rheological constraints of the lithosphere, among othermodel parameters, exert a first-order control for plateau formation.

The Eastern Anatolian Plateau presents a geologic puzzle: surface elevations of similar to 2 km occur in an area with average crustal thickness (35-45 km) and thin mantle lithosphere (60-70 km). Despite various hypotheses proposing processes including slab break-off, delamination, and crustal shortening, the mechanisms behind the plateau's formation remain debated. Geological reconstructions show Neotethyan subduction along two branches, but the role of one versus two slabs in the evolution of the plateau remains uncertain. This study addresses a key geodynamic question: Is the observed plateau evolution consistent with both single- and double-slab scenarios? We conduct high-resolution 2-D numerical experiments that test both scenarios. Our results reveal that a single-slab subduction model can produce a plateau with an average uplift similar to the observed data in terms of magnitude, but it fails to replicate the broadness of the plateau as observed today, stretching over a distance of 350 km. In contrast, in a double-slab subduction system, the northern branch of the NeoTethys first delaminates and breaks off before break-off of the southern branch, resulting in a topographic evolution that is better aligned with observations, including a southwardyounging surface uplift of 2 km. This scenario also aligns more closely with geophysical and geological observations, including crustal deformation and subsurface structures seen in seismic tomography. Our findings suggest that the double-slab model provides a more coherent explanation for the development of the Eastern Anatolian Plateau. While this model is particularly applicable to the Tethyan orogenic system, it may offer insights into other regions with complex subduction dynamics such as India-Eurasia collision.

This work presents a study of late Quaternary activity on the Jinta Nanshan Fault (JTF), to constrain its properties including seismic hazard, and to understand the tectonic evolution of the northern edge of the Tibetan Plateau. The JTF has developed during northeastward growth of the Qilian fold-and-thrust belt and eastward growth of the Altyn Tagh Fault. Based on remotely-sensed image interpretation and field investigation, trench studies, high-resolution terrain construction and Optical Stimulated Luminescence dating, we study the fault geometry and slip motion, and constrain the slip rate and the latest earthquake for the JTF. The JTF continues as far southeast as the Heihe River and shows predominantly left-lateral strike-slip displacement. The left-lateral slip rate is 0.27-0.48 mm/yr since late Pleistocene, much larger than the vertical slip rate of 0.05 +/- 0.01 mm/yr. The latest rupture event of the JTF is slightly before 1 ka, which could be related to the poorly-recorded 756 CE earthquake in Hexi Corridor, and is also associated with fresh offset during this earthquake in the geomorphology of the east segment of the JTF. Strike-slip offset in this earthquake is estimated as 3.2 +/- 0.4 m, with a rupture length of at least similar to 13 km, indicating a moment magnitude of 6.4-7.2. We estimate the recurrence interval as 8-13 ka, based on the size of the latest offset and the slip rate of 0.27-0.48 mm/yr. These results indicate that the strike-slip continuation of the Altyn Tagh Fault dominates the slip behaviour of the JTF. The small strike-slip rate, and the match between the strike-slip of the JTF and the vertical slip of the North-South Normal Faults (NSF) at its eastern end, permit the interpretation that the slip of Altyn Tagh Fault is completely accommodated by crustal extension at the NSF, and dies out at the eastern end of the Jinta Nanshan region.

Many rifts are influenced by pre-existing structures and heterogeneities during their evolution, a process known as structural inheritance. During rift evolution, these heterogeneities may aid rift nucleation, rift growth, and the segmentation of faults; encourage the linkage of various segments; or even inhibit the formation of faults. Understanding how structural inheritance influences early rift evolution could be vital for evaluating seismic risk in tectonically active areas. The Shanxi Rift in the north of China is an active rift system believed to have formed along the trend of the Proterozoic Trans-North China Orogen; however, the influence of these pre-existing structures on the present-day rift architecture is poorly understood. Here, we use tectonic geomorphological techniques, e.g. the hypsometric integral (HI), channel steepness (ksn), and local relief, to study the evolution of the Shanxi Rift and identify areas of higher tectonic activity. We found that the HI was less sensitive to lithology and more valuable in evaluating the tectonic signal and that activity is concentrated in two rift interaction zones (RIZs) formed between the Xinding, Taiyuan, and Linfen basins. We then evaluated the relationship between the active faults and mapped pre-existing structures, finding that many faults formed parallel to inherited structures, while faults in the RIZs often cross-cut these structures. Based on these observations, we propose a new model for the evolution of the Shanxi Rift, where inherited structures play an important role in the initial segmentation of the rift, which, in turn, controls the development of the RIZ structures.

Early Cretaceous intraplate volcanic rocks are widespread in NE Asia, but their origin remains controversial. This work presents zircon U-Pb ages, whole-rock element and Sr- Nd isotope data for mafic volcanic rocks from the Erlian Basin, a wide rift basin in NE Asia. There were two episodes of Early Cretaceous mafic volcanism in the Erlian Basin, and the eruptions show contrasting geochemical com- positions. The early mafic volcanic rocks, with U-Pb ages of ca. 140-135 Ma, show slightly depleted Sr-Nd isotope compositions (I Sr (t) = 0.7042-0.7052; epsilon Nd (t) = + 0.82 to + 3.0) and arc-like trace-element composi- tions, which are derived from subduction- related fluid/melt metasomatized lithosphere mantle. The late mafic volcanic rocks (dated at ca. 125 Ma) have enriched Sr-Nd isotopes (I Sr (t) = 0.7055-0.7077; epsilon Nd (t) = - 0.50 to - 2.67) and oceanic-island basalt (OIB)-like trace-element compositions, revealing the metasomatism of melts from crustal materi- als and asthenosphere mantle. The two types of mafic volcanic rocks may record the in- teractions of the mantle and melts from the subducted paleo-Pacific oceanic slab at dif- ferent depths. The landward-then-oceanward migration pattern of the Mesozoic volcanism from NE Asia can be explained by the flat sub- duction and subsequent slab roll-back of the Paleo-Pacific Ocean, consistent with migra- tion patterns from the North China Craton and South China Block, implying similar Ju- rassic-Cretaceous subduction evolution along the entire East Asia margin. Some Late Juras- sic to Early Cretaceous dates from east Mon- golia and the southern margin of the Erlian Basin diverge from this trajectory. In combi- nation with previous studies, we suggest that the Early Cretaceous pervasive intraplate vol- canism in the Erlian Basin and adjacent areas of NE Asia mainly resulted from the slab roll- back of the Paleo-Pacific Ocean with a com- bined effect from the post-collision extension of the Mongol-Okhotsk orogen.