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Hydrocarbon seeps are common manifestations of gas leakage from the seafloor. However, the fate of methane seepage within the gas hydrate stability zone at active margins is poorly constrained. This study presents a 40‐thousand‐year record of hydrocarbon seepage archived by a ∼5‐m long core composed of authigenic carbonate from the Yam Seep area, Four‐Way Closure Ridge off SW Taiwan. Different carbonate microfacies could be distinguished: Consolidated microcrystalline aragonite representing lithified host sediments intercalated by pure aragonite present in 10–50 cm thick intervals in the core. These aragonite intervals are interpreted as having precipitated within former fractures in the host rock. High resolution U‐Th dating of these aragonites is interpreted to record the minimum age of the opening of these fractures. The chronology of aragonite precipitation throughout the core suggests a record of continuous seepage from ∼41 to 2 ka that fluctuated in intensity over this time period. The chronology of putative fracturing events and observed carbonate precipitation suggest (a) an active period of fracturing and seepage from ∼37 to 27 ka, (b) a more quiescent period from ∼27 to 16 ka, followed by (c) another active period from ∼16 to 12 ka. A schematic model illustrates the evolution of carbonate formation within the core influenced by faulting, fracturing, erosion, gas hydrate accumulation, and aragonite precipitation and provides a unique 40,000‐year‐old record of methane seepage and crucial insights into the dynamics of long‐term seepage systems at active margins. Key Points A 40‐thousand‐year history of hydrocarbon seepage at an active margin accretionary ridge off SW Taiwan Uranium‐Thorium dating of authigenic carbonate reveals alternating periods of seepage activity and quiescence Dating of fracture boundaries provides evidence for episodes of tectonic and seepage activities

There has been a long debate about how passive (Atlantic‐type) margins can convert to active (Andean) margins, particularly if they can do so directly, or some other process such as an arc‐continent collision must intervene (Burke et al., 1984; Dewey, 1969, https://doi.org/10.1016/0012‐821x(69)90089‐2; Kusky & Kidd, 1985). Most numerical models have long‐suggested that only very young passive margins can be sites of subduction initiation since old margins become stronger as they cool and develop thick sedimentary piles during thermal subsidence (e.g., Cloetingh et al., 1982, https://doi.org/10.1038/297139a0, 1989, https://doi.org/10.1007/bf00874622; 1996; Zhong & Li, 2019, https://doi.org/10.1029/2019gl084022), whereas other analog and numerical models have suggested that old passive margins may spontaneously convert to subduction zones (e.g., Bercovici & Mulyukova, 2021, https://doi.org/10.1073/pnas.2011247118; Faccenna et al., 1999, https://doi.org/10.1029/1998jb900072; Nikolaeva et al., 2010, https://doi.org/10.1029/2009jb00654; Stern & Gerya, 2018, https://doi.org/10.1016/j.tecto.2017.10.014; Zhang et al., 2023, https://doi.org/10.1029/2023gl103553). Plain Language Summary How do passive margins convert to active margins? The evidence presented by Zeng et al. (2025), https://doi.org/10.1029/2025gc12197 and a survey of the literature about past well‐documented events overwhelmingly points to the process of arc‐polarity reversal following arc‐continent collision. The time frame of such events is such that they usually start very soon after or even during the late stages of collision, and the process is typically complete within 10–20 million years (e.g., Brown & Ryan, 2011, https://doi.org/10.1007/978‐3‐540‐88558‐0). The shortest documented cases (5–10 million years) include Timor, Taiwan, and the Proterozoic Wopmay orogen, with the longest cases (25–30 million years) including the Urals and Kohistan (Brown & Ryan, 2011, https://doi.org/10.1007/978‐3‐540‐88558‐0). Intermediate durations (∼10–12 million years) of collision to arc polarity reversal include Kamchatka, and the Grampian and Taconic collisions, as discussed above. The evidence is clear: passive margins rapidly convert to active (Andean) margins by subduction polarity reversal following arc‐continent (with passive margin) collision. Key Points Passive margins convert to active margins after collisions with arcs and subduction polarity reversal No examples are known of spontaneous subduction initiation at passive margins Zeng et al. (2025, https://doi.org/10.1029/2025gc12197) present a new example of subduction initiation and subduction polarity reversal after arc collision with passive margin

Plate tectonics theory, established in the 1960s, has been successful in explaining many geological phenomena, processes and events that occurred in the Phanerozoic. However, the theory has often struggled to provide a coherent framework in interpreting geological records in continental interior and Precambrian period. In dealing with the relationship between plate tectonics and continental geology, continental interior tectonics was often separated from continental margin tectonics in the inheritance and development of their structure and composition. This separation led to the illusion that the plate tectonics theory is not applicable to Precambrian geology, particularly in explaining the fundamental geological characteristics of Archean cratons. Although this illusion does not mean that the Archean continental crust did not originate from a regime of plate tectonics, it led to the development of alternative tectonic models, often involving vertical movements under a regime of stagnant lid tectonics, including not only endogenous processes such as gravitational sagduction, mantle plumes and heat pipes but also exogenous processes such as bolide impacts. These vertical processes were not unique to the Archean but persisted into the Phanerozoic. They result from mantle poloidal convection at different depths, not specific to any particular period. Upgrading the plate tectonics theory from the traditional kinematic model in the 20th century to a holistic kinematic-dynamic model in the 21st century and systematically examining the vertical transport of matter and energy at plate margins, it is evident that plate tectonics can explain the common geological characteristics of Archean cratons, such as lithological associations, structural patterns and metamorphic evolution. By deciphering the structure and composition of convergent plate margins as well as their dynamics, the formation and evolution of continental crust since the Archean can be divided into ancient plate tectonics in the Precambrian and modern plate tectonics in the Phanerozoic. In addition, there are the following three characteristic features in the Archean: (1) convective mantle temperatures were 200–300°C higher than in the Phanerozoic, (2) newly formed basaltic oceanic crust was as thick as 30–40 km, and (3) the asthenosphere had a composition similar to the primitive mantle rather than the depleted mantle at present. On this basis, the upgraded plate tectonics theory can successfully explain the major geological phenomena of Archean cratons. This approach provides a new perspective on and deep insights into the evolution of early Earth and the origin of continental crust. In detail, Archean tonalite-trondhjemite-granodiorite (TTG) rocks would result from partial melting of the over-thick basaltic oceanic crust at convergent plate margins. The structural patterns of gneissic domes and greenstone keels would result from the buoyancy-driven emplacement of TTG magmas and its interaction with the basaltic crust at convergent margins, and komatiites in greenstone belts would be the product of mantle plume activity in the regime of ancient plate tectonics. The widespread distribution of high-grade metamorphic rocks in a planar fashion, rather than in zones, is ascrible to separation of the gneissic domes from the greenstone belts. The shortage of calc-alkaline andesites in bimodal volcanic associations suggests the shortage of sediment accretionary wedges derived from weathering of granitic continental crust above oceanic subduction zones. The absence of Penrose-type ophiolites suggests that during the subduction initiation of microplates, only the upper volcanic rocks of the thick oceanic crust were offscrapped to form basalt accretionary wedges. The absence of blueschist and eclogite as well as classic paired metamorphic belts suggests that convergent plate margins were over-thickened through either warm subduction or hard collision of the thick oceanic crust at moderate geothermal gradients. Therefore, only by correctly recognizing and understanding the nature of Archean cartons can plate tectonics reasonably explain their fundamental geological characteristics.

Mantle‐derived magma flux has a first‐order control on long‐term volcanic productivity, volatile cycling, and crustal growth in convergent margins. However, the factors controlling it remain unclear. We used a simplified, 3D conceptualization of an intraoceanic subduction zone and petrologic constraints on mantle melting to calculate mantle‐derived magma flux from the “bottom up”, and test the sensitivity of mantle‐derived magma flux to a variety of input variables. Estimates of mantle‐derived flux from our model can be compared to existing “top down” models based on erupted volumes and crustal growth models and is also a jumping‐off point from which more complex models of mantle‐derived magma flux at a variety of scales may be developed. We find that the total volume of mantle available to melt exerts the most significant control on mantle‐derived magma flux between different arcs. At a given arc, convergence rate and the extent of melting have the greatest impact on mantle‐derived magma flux. Variation in flux caused by variations in orthogonal convergence rates within the Aleutians may cause variability in mantle‐derived magma flux along‐arc.

Continental crust forms and evolves above subduction zones as a result of heat and mass transfer from the mantle below. The nature and extent of this transfer remain debated. Although it has been recognized that arc magmatism at active continental margins can be cyclical at 50- to 1-Myr timescales, such cyclicity has not been recognized in the back-arc. Here we investigate the melting of sedimentary rocks in the continental back-arc of the western Gondwana margin during the Cambrian–Ordovician Famatinian orogeny of Northwest Argentina. We determine the U−Pb ages of zircons that formed during crustal melting and find that they range from 505 to 440 million years ago, concentrated into age groups spaced by 10–15 Myr. This suggests multiple and cyclical melting events in the continental back-arc, which matches the more than 60 Myr duration of the magmatic activity in the arc and demonstrates that thermal and magmatic cyclicity also extends to the continental hinterland. We conclude that back-arc melting reflects a long-lasting, pulsating, cyclical heat transfer from mantle to crust that leads to thorough crustal reworking, transforming sedimentary rocks into crystalline continental crust. Thus, while magma transfer from the mantle promotes crustal growth in convergent margins, cyclical melting promotes crustal maturation of the back-arc.Melting of sedimentary rocks in the continental back-arc is cyclical with peaks of magmatism every 10 to 15 million years, according to zircon ages from Paleozoic western Gondwana margin samples.

Turbidites on active margins represent key archives of great earthquakes, yet turbidity currents triggered by non‐seismic events complicate paleoearthquake records and influence geochemical budgets. Sediment cores collected from highstand‐detached Astoria Canyon address whether non‐seismic turbidity currents are preserved in canyon stratigraphy. Detailed analysis of a core indicates fluvial origin of turbidites based on sedimentology, geochronology, and organic matter composition. Turbidites are ∼15 cm thick, graded, and laminated. Turbidite 210Pb activity is low, and depositional ages align with major Columbia River floods. Turbidite organic matter is terrestrial and modern (−26‰ δ13Corg, 18 C:N, ∼6 mg lignin per 100 mg OC). These deposits provide the first direct evidence of modern non‐seismic turbidite deposition in northern Cascadia, with implications including that highstand stratigraphy preserves non‐seismic events, turbidite composition reflects sediment source, and turbidite deposition represents a significant component of sediment and carbon accumulation.

We focus on an active continental margin related to northwards subduction during the Eocene in which sedimentary melange (‘olistostromes’) forms a key component. Maastrichtian – Early Eocene deep-marine carbonates and volcanic rocks pass gradationally upwards into a thick succession (<800 m) of gravity deposits, exposed in several thrust sheets. The lowest levels are mainly siliciclastic turbidites and debris-flow deposits. Interbedded marls contain Middle Eocene planktonic/benthic foraminifera and calcareous nannofossils. Sandstones include abundant ophiolite-derived grains. The higher levels are chaotic debris-flow deposits that include exotic blocks of Late Palaeozoic – Mesozoic neritic limestone and dismembered ophiolite-related rocks. A thinner sequence (<200 m) in one area contains abundant redeposited Paleogene pelagic limestone and basalt. Chemical analysis of basaltic clasts shows that some are subduction influenced. Basaltic clasts from unconformably overlying alluvial conglomerates (Late Eocene – Oligocene) indicate derivation from a supra-subduction zone ophiolite, including boninites. Taking account of regional comparisons, the sedimentary melange is interpreted to have formed within a flexurally controlled foredeep, floored by continental crust. Gravity flows including large limestone blocks, multiple debris flows and turbidites were emplaced, followed by southwards thrust imbrication. The emplacement was possibly triggered by the final closure of an oceanic basin to the north (Alanya Ocean). Further convergence between the African and Eurasian plates was accommodated by northwards subduction beneath the Kyrenia active continental margin. Subduction zone rollback may have triggered collapse of the active continental margin. Non-marine to shallow-marine alluvial fans prograded southwards during Late Eocene – Oligocene time, marking the base of a renewed depositional cycle that lasted until latest Miocene time.

Brief pulses of intense volcanic eruptions along convergent margins emit substantial volatiles that drive climatic excursions that can lead to major extinction events. However, correlating volcanic outpouring to environmental crises in the geological past is often difficult due to poor preservation of volcanic sequences and the need for precise dating methods. Here we present a high-fidelity CA-TIMS U–Pb zircon record of an end-Permian flare-up event in eastern Australia, which involved the eruption of >39,000–150,000 km 3 of silicic magma in circa 4.21 ± 0.5 million years. A correlated high-resolution tephra record (circa 260–249 Ma) in the proximal sedimentary basins suggests recurrence of eruptions from the volcanic field in intervals of ~51,000–145,000 years. Peak eruption activity at 253 ± 0.5 million years ago is chronologically associated with intervals of pronounced species decline and the demise of the Glossopteris forests in the initial stages of the end-Permian mass extinction event (~1–2 Myr). Simultaneous eruptions along multiple arcs around the globe occurred at the same time as eastern Australia. In conjunction, these global eruptions are considered as a trigger of greenhouse crises and ecosystem stress that preceded the catastrophic eruption of the Siberian Traps. Pulses of silicic arc magmatism—and associated volatile emissions—helped set the timing and magnitude of the environmental disruptions that caused the end-Permian mass extinction, according to U–Pb zircon dating of silicic volcanic and related tephra sequences in eastern Australia.

Understanding the cause and location of the end‐points of thrust earthquake ruptures is critical yet unresolved question in seismic hazard assessment for convergent margins, where numerous destructive earthquakes have occurred. Here, we offer a novel perspective on rupture termination by examining the arrest of the 1906 M 8.0 Manas earthquake in northwestern China. Integrated field surveys, seismic profiles, and microseismicity data reveal that rupture terminated at the actively growing Xiaodushan anticline. This anticline lies parallel to and in the hanging wall of the seismogenic fault. We propose active folding acts as an efficient rupture‐arrest barrier, partitioning seismic energy into strata uplift and microseismicity. Furthermore, comparative analysis of global thrust earthquakes identifies two termination mechanisms: fault geometric complexities and external structural barriers. These findings contribute to deeper understanding of rupture lengths and earthquake magnitudes for seismic hazard assessment in convergent margins globally.

Mantle metasomatism is a common phenomenon in convergent margins; however, metasomatism by subducted sediments and their role in alkaline magma generation remain poorly understood. Alkaline rocks from the Tangra‐YumCo rift (TYR) in southern Tibet show a unique geochemical composition among post‐collisional volcanic rocks of the Lhasa terrane. These rocks exhibit high potassium (up to 10.59 wt. %) and silica (up to 70.01 wt. %) contents, very light boron (B) isotopic ratios (δ11B = −14.85‰ to −29.72‰), and negative mass‐independent fractionation in mercury (Hg) isotopes (Δ199Hg = 0 to −0.54‰). We propose that these magmas were derived from a mantle source that was metasomatized by continental sediments, which underwent extensive dehydration during subduction. Slab tearing beneath southern Tibet triggered partial melting of this metasomatized domain around 13.0 ± 0.2 Ma (U‐Pb). The resulting magmas record the reactivation of a sediment‐enriched mantle source previously modified by continental subduction. These results demonstrate that deeply recycled continental sediments, like their oceanic counterparts, can contribute to mantle metasomatism and ultimately to the genesis of compositionally extreme magmas. The combined application of B‐Hg‐O‐Hf isotopes provides new constraints on sediment recycling and the thermal reactivation of enriched mantle domains in post‐collisional orogenic settings.