Marine phosphorus (P) availability plays a key role in regulating ocean primary productivity and biogeochemical cycling, including during extreme climatic transitions such as the Sturtian Snowball Earth deglaciation. However, the mechanisms linking P availability with ocean redox dynamics and nutrient cycling during that time remain poorly constrained. Here, we integrate mineralogical observations with in-situ analyses of major and trace elements such as rare earth elements and yttrium (REY), strontium (Sr) isotopes in apatite, and bulk-rock P/Fe(100) ratios from three well-preserved Sturtian-aged iron formations (IFs) in South China. Spatial trends in key geochemical indicators across the IF sites-including declining Eu anomalies, Pr/YbPAAS ratios and increasing Y/ Ho ratios from the Tongdao through Jiangkou to Xinyu IFs, elevated Mn contents, apatite 87Sr/86Sr ratios, and the highest bulk-rock P/Fe(100) ratios in the Xinyu IF near the continental margin-collectively suggest that seawater chemistry during the Sturtian deglaciation was modulated by combined inputs from continental weathering and hydrothermal fluxes. Our results highlight that intensified continental weathering, coupled with dynamic redox conditions characterized by Fe-Mn cycling across the redoxcline and active oceanic circulation, governed marine P recycling during this period. Within this framework, terrestrially derived P was transported into the upper, oxygenated water column where it adsorbed onto Fe-Mn oxyhydroxides. Upon settling across the redox chemocline into anoxic bottom waters, these particles released P. Part of this released P likely precipitated as authigenic carbonate fluorapatite incorporating REY and Sr, while the remainder was recycled back into the upper water column, increasing the availability of bioavailable P. This recycling potentially stimulated primary productivity and facilitated the expansion of oxygenated surface waters. Such feedback may have helped sustain Cryogenian marine ecosystems and paved the way for subsequent pivotal ecological transitions, including a shift from prokaryote- to eukaryote-dominated phytoplankton communities and the emergence of complex multicellular eukaryotes.

A rifted margin can be regarded, in the first place, as a crustal thinning taper framed by “box-shaped” continental and oceanic crusts whose top basement and Moho are parallel. Attempts to understand the relationship between lithosphere extension, crustal thinning and strain localization have been addressed in part by characterizing and modeling rift modes. However, a weakness of models stems from their using generalized physical parameters and initial conditions, while each system is unique in terms of its geological complexity. In this study, we develop a new approach to investigate the relation between crustal shape, the nature of the top basement and the accommodation space to reveal the link between extension, strain localization and crustal thinning in the northern South China Sea (N-SCS). Our results show the following: (1) box-shaped crusts may indicate no or minor extension, or extension compensated by crustal flow and/or magmatic additions; (2) crustal thinning and strain localization occurred through extensional detachment faults coevally during the rifting of the N-SCS; (3) strain localization was triggered or enhanced by magmatic weakening, and the weak crustal rheology at the onset of the rifting favored the formation of detachment faults; and (4) the inherited composition of the crust (magmatic rocks in the arc and meta-sediments in the forearc) controls the distribution of crustal thinning. We propose that the different initial conditions, changes in extension rates and the presence/absence of subduction dynamics account for the different rift evolutions observed in the SCS and Atlantic-type rift systems.

Accurately quantifying and analyzing the distribution, spatial autocorrelation, and sources of heavy metals (HMs) in soil and river sediments is crucial for assessing human and geological impacts on regional environments. This study collected 9631 soil and 61 sediment samples from the upstream Yishu River Basin, characterized by mountainous reservoirs, to systematically investigate the spatial distribution and potential sources of HMs. We suggest that mountainous reservoirs significantly intercept and regulate HMs in sediments. The average HM concentrations were higher in soils than in sediments, with elevated levels observed in mountainous regions and fault zones. Soils in clastic rock areas had notably higher HM concentrations than those in carbonate rock areas. Using bivariate local indicators of spatial association (LISA) and the positive matrix factorization (PMF) model, five major sources of HMs in soils and sediments were identified: agricultural activities (Cu, Zn, Cd), geological background (Cr, Ni), coal combustion (Hg), mining activities (As, Cu, Ni), and traffic-industrial mixed sources (Pb, As, Cr, Cd). This approach pinpointed the two major hotspot areas located in the Yishui Urban Area and the Gongdanshan Mining Area, providing a scientific basis for the management and prevention of HMs contamination in key water source areas.

Metamorphic buried hill reservoirs possess complex pore structures, making the evaluation of their effectiveness particularly challenging. This study explores the influence of lithology and stress conditions on fracture development in such reservoirs, aiming to improve predictions of effective storage spaces. Three representative metamorphic rocks from the Bohai Bay Basin: plagioclase amphibolite, gneissic granite, and monzogranite were subjected to mechanical testing under compressive and tensile stresses. Acoustic emission (AE) monitoring was used to track energy release and the spatiotemporal evolution of microfractures during deformation, complemented by thin-section analysis of post-failure samples to examine microfracture morphology and density. The results show that tensile stress more readily induces rock failure but typically produces narrow, localized damage zones, whereas compressive stress promotes the development of broader, more interconnected fracture networks. Under tensile loading, all three lithologies exhibit similar axial splitting behavior, with granitic rocks forming slightly wider fracture zones than amphibolite. Under compressive loading, distinct macroscopic failure modes are observed among the lithologies. Analysis of microfracture parameters and spatial distributions reveals that monzogranite exhibits extensive microfracture activity and wide fracture zones, indicating a higher potential for forming interconnected secondary porosity and making it the most favorable reservoir lithology among those tested. This study provides detailed insights into fracture evolution across different lithologies under varying stress conditions and offers experimental evidence to support improved predictions of effective reservoirs in deep metamorphic settings.

Abstract The complex tectonic evolution and regional remagnetization in East Asia since the Mesozoic have led to debates over plate reconstructions. By synthesizing high‐quality paleomagnetic poles and geological data, this study develops a new plate reconstruction model for East Asia between 270 and 110 Ma. In our model, the North China Plate and South China Plate collided in an east‐to‐west progression from 260 to 200 Ma, forming a unified East Asian continental margin. The majority of the Cimmerian microplates (e.g., South and North Qiangtang microplates) accreted to the southern margin of East Asia by 220 Ma, while the Lhasa Microplate accreted later around 110 Ma. A ∼7° southward movement of East Asia between 180 and 160 Ma is revealed by our model, consistent with the occurrence of a proposed True Polar Wander (TPW) event in this interval, rather than an anomalously rapid motion (“monster shift”) at 160–145 Ma as previously proposed. The subduction of Mongol–Okhotsk oceanic slabs in the northern polar region likely played an important role in driving the Jurassic TPW. The new model aligns closely with geological records and provides a new framework for advancing our understanding of Earth's system evolution.

The source-to-sink (S2S) system serves as a critical dynamic archive for reconstructing landscape evolution over geological timescales, linking terrestrial provenances to marine sinks through diverse transport mechanisms and depositional processes. This integrative framework is essential for assessing the long-term interactions among climate change, tectonics, denudation, sea-level fluctuations and the coupling mechanisms among them. This paper presents the provenance evolution of the West African basins since the Cenomanian of Middle Cretaceous using the parallel scalable paleo-landscape evolution software (goSPL), which enables simulations of basin and landscape evolution at regional to global scales. Our results demonstrate that regional drainage dynamics have acted as a primary triggering mechanism to control basin sediment loading. The models highlight the deep-time West African source-to-sink episodes that triggered the drainage dynamics, marginal progradation, depocenter evolution and marginal flux bypassing. In the Meso-Cenozoic, the proximal and distal basement highs have constituted the dominant sediment sources to feed the marginal and intraplate transient sinks, with maximum precipitation concentrated in the equatorial zone and arid conditions along the southern and northern African margins. By comparing independent geological records of the India-Eurasia and Arabia-Eurasia collisions, the study reveals that source-to-sink evolutionary events in West Africa are closely linked to the stepwise closure of the Neo-Tethys Ocean. These findings highlight an integrated geomorphic approach for refining deep-time source-to-sink reconstructions across rift systems and passive margins, while also revealing the interaction mechanisms among plate–mantle dynamics, topographic reorganization, ocean–climate circulation, and the long-term carbon cycle.

The Indian Summer Monsoon (ISM) is an important part of the global climate system, affecting the economic prosperity of heavily populated regions. On the orbital scale, the significant phase differences in the precession band between ISM records from marine sediment and speleothem delta 18O records have furthered the debate about the driving mechanism(s) of the ISM. Thus, to examine the ISM variations on the orbital scale and their potential forcings, we conducted environmental magnetic and geochemical measurements on marine sediment from the Ninety-east Ridge in the south Bay of Bengal covering the past 260 k.y. Environmental magnetic results indicate that coarser (finer) magnetic grain size corresponds to arid (humid) periods. Magnetic grain size is associated with the intensification of chemical weathering, reflecting the pedogenic process in the floodplains influenced by the ISM precipitation. Therefore, combined with these five proxy records from the core CJ04-57 in the Ninety-east Ridge, we build a new multi-proxy record of the ISM stack. Our ISM stack exhibits a-68 degrees (similar to 4.5 k.y.) lag with maximum Northern Hemisphere summer insolation (NHSI) but is nearly in phase with the global ice volume and greenhouse gas in the precession band. These results emphasize that ISM rainfall is further influenced by internal forcing mechanisms such as global ice volume and greenhouse gas besides NHSI.

Authigenic carbonate precipitation at methane seeps transfers methane-derived carbon into the geosphere, thereby regulating the global methane budget. Calcium (Ca) isotopic fractionation in cold seep carbonates is primarily controlled by carbonate mineral polymorph and precipitation rate. However, current understanding of calcium isotopic fractionation is largely based on physico-chemical processes, neglecting the integral role of biogeochemical processes. Here, we analyzed seep carbonates from the Okinawa Trough and Jiulong Methane Reef using mineralogical, geochemical, and lipid biomarker proxies. The results show that the formation of the aragonitic and calcitic carbonates was mediated by distinct microbial communities ANME-2/DSS and ANME-1/DSS, respectively. The lower δ44/40Ca values of aragonitic carbonates (0.96 ± 0.08‰) compared to the calcitic carbonates (1.24 ± 0.14‰) demonstrate the mineral phases and precipitation rates were the controlling factors mediated the Ca isotope fractionation during carbonate precipitations. Given the evidence that ANME-2/DSS affect the Ca isotopic fractionation of aragonitic carbonates, the distinct microbial consortia (ANME-2/DSS vs. ANME-1/DSS) may have played a role in Ca isotopic fractionation in this study by modifying local ion concentrations and pH. More future studies are needed to improve our understanding of microbial consortia on Ca isotopic fractionations.

Molybdenum (Mo) and its isotopic composition (δ98Mo) can serve as robust proxies for reconstructing paleo-oceanographic and paleoenvironmental conditions. Seep carbonates, in particular, hold potential for archiving contemporaneous seawater δ98Mo signatures. However, this application requires that Mo be sourced exclusively from seawater. This prerequisite is complicated by the frequently complex sources of Mo in cold seep environments, particularly within hydrothermally influenced systems. Here, we conducted elemental and Mo isotopic analyses of seep carbonates collected from the middle (MOT) and northern Okinawa Trough (NOT). Seep carbonates from NOT, in contrast to those from MOT, exhibit distinctive hydrothermal vent signatures, including generally lighter δ56Fe (min: −0.49‰), elevated Fe/Al ratios (max: 2.90) that show positive correlations with the enrichment factors of V, Zn, As, Sb (VEF, ZnEF, AsEF, SbEF) and anomalous U enrichments (UEF max: 53). In addition, NOT seep carbonates show markedly lower δ98Mo values (−0.55‰ to +0.99‰) compared to those from MOT (+1.44‰ to +2.23‰; avg. +1.85‰), a pattern attributed to the incorporation of isotopically light, hydrothermally derived Mo into NOT carbonates. A corroborating mass balance model demonstrates that the measured δ98Mo values in NOT seep carbonates fall within the field defined by Mo sourced from hydrothermal plumes, whereas δ98Mo values of the MOT seep carbonates align with a seawater-dominated source. Our findings reveal that seep carbonates can reliably record marine chemical signals, and crucially, they underscore the critical need to account for source influences when interpreting Mo isotopes in sedimentary archives. This work thus significantly advances our understanding of Mo cycling in the ocean.

The Central Asian Orogenic Belt (CAOB) preserves the complete evolution of the Paleo-Asian Ocean (PAO). The Changchun–Yanji Suture Zone, the easternmost PAO suture between the North China Craton (NCC) and the Zhangguangcai continental arc–Jiamusi–Khanka Block (ZJKB), records the final closure of the PAO, but its timing, position and mechanism remain debated. We integrate structural analysis of ductile shear zones with zircon U–Pb geochronology to constrain the PAO closure processes in NE China. Two NW–SE-trending ductile shear zones, the Jiapigou and Gudonghe ductile shear zones, record thrust-related deformation with opposite directions across the Yalu River Fault (YRF), characterized by SW-directed thrusting to the west of the YRF and NE-directed thrusting to the east. Zircon U–Pb ages constrain this deformation to the Late Triassic, ca. 229–220 Ma. Structural correlations with high-strain belts, the εHf(t) spatial distribution, and biogeographic boundaries delineate the eastern PAO suture along Kaiyuan–Shancheng–Huadian–Liangjiang–Xiaohuanggou–Baijin. We interpret the YRF originally as a lithosphere-scale transform fault. Before the final closure, the PAO underwent ridge-involved bidirectional subduction on both sides of the YRF. During closure, the ridge segment on the west of the YRF was subducted southward beneath the NCC while the remaining slab continued northward subduction, whereas on the east of the YRF, the ridge segment was subducted northward beneath the ZJKB and the remaining slab continued southward subduction. In the final closure stage, the transform fault (future YRF) cut into both continental margins, resulting in oppositely directed thrusting on both sides of the YRF. This deformation records the collisional orogenic stage associated with the final closure of the PAO. Subsequent Paleo-Pacific subduction may have reactivated the inherited Yalu River Fault and adjacent shear zones, further modifying the earlier PAO-related structures.

The Middle Jurassic was marked by significant magmatic activity in the interior of South China. This study presents integrated zircon and baddeleyite U–Pb geochronology, Hf–O isotopes, whole-rock geochemistry, and Sr–Nd isotopic data for two Middle Jurassic magmatic units in the southern Qin–Hang belt within the interior of the South China Block. Zircon and baddeleyite U–Pb dating yielded crystallization ages of 167–162 Ma for the Luorong Pluton and 163–162 Ma for the Xishan Pluton. The Luorong syenites exhibit moderate SiO2, high total alkali, and low MgO and Fe2O3T, along with baddeleyite εHf(t) values of + 1.4 to + 7.9 and mantle-like zircon δ18O values (5.11–6.54 ‰). Their trace element characteristics resemble those of Jurassic shoshonitic rocks in the southern Qin–Hang belt. The Xishan granites show A-type affinities with high SiO2 contents, low MgO and Fe2O3T contents, and negative Nb, Ta, Sr, and Eu anomalies. They display evolved whole-rock (87Sr/86Sr)i ratios (0.70562–0.70632), εNd(t) values (−0.9 to + 0.4), zircon εHf(t) values (−0.6 to + 7.2) and δ18O values (7.16–8.06 ‰); a mafic microgranular enclave from the Xishan Pluton yields corresponding values of 0.70494, +1.9, −0.5 to +8.1, and 6.94–8.66 ‰, respectively. The Luorong syenites originated from a mixed source involving both asthenospheric and metasomatized lithospheric mantle components, followed by fractional crystallization. The Xishan A-type granites record a mixed mantle–crustal origin, involving magma mingling, as evidenced by the enclaves, followed by fractional crystallization. These contrasting differentiation pathways reflect spatially heterogeneous lithospheric extension and asthenospheric upwelling beneath the interior of the South China Block during the Middle Jurassic.

Coastal lagoons along the eastern Chinese coast are sensitive sedimentary archives at the land-sea interface and can provide valuable information on mid- to late Holocene hydroclimatic variability associated with the East Asian summer monsoon (EASM). Here we analyse a mid- to late Holocene sediment core YH-3 (ca. 6.2-2.9 cal kyr BP) from Yuehu Lagoon on the Shandong Peninsula, eastern China, integrating rock magnetic, diffuse reflectance spectroscopy (DRS), scanning electron microscopy and energy-dispersive spectroscopy (SEM-EDS), and geochemical approaches to evaluate the paleoenvironmental significance of magnetic mineral variations. Major and trace element data indicate that the lagoon sediments were supplied mainly by local catchments, with only minor distal contributions. The sediments are dominated by detrital ferrimagnetic minerals, mainly titanomagnetite, with subordinate high-coercivity minerals (goethite and hematite), and authigenic pyrite formed during early diagenesis. Although framboidal pyrite and thermomagnetic results indicate that sulfate diagenesis occurred, the preservation of detrital titanomagnetite and the weak relationship between total sulfur (TS) and the magnetic grain-size proxy chi(ARM)/SIRM suggest that neither sulfidic diagenesis nor sea-level change exerted a primary control on the magnetic record. Instead, the downcore variations in chi(ARM)/SIRM are interpreted to reflect EASM-driven changes in runoff, terrigenous input, and redox conditions. Three weak EASM intervals are identified at similar to 5.5, 5.0, and 2.9 cal ka BP, characterized by reduced chi(ARM)/SIRM, S-ratios, total organic carbon (TOC), and goethite contents inferred from DRS measurements, in agreement with independent paleoclimatic records from northern China. These results demonstrate that Yuehu Lagoon preserves a robust multiproxy record of midto late Holocene EASM variability.

Eolian sediments from the Northwest Pacific Ocean can provide crucial archives to understand the evolution of Asian interior aridity. As the dominant mid-latitude dust conveyer, the intensity and displacement of westerly variations can exert a decisive influence on Asian interior precipitation patterns. However, details of the mechanisms by which the westerlies control regional humidity remain elusive. We investigate here Northwest Pacific Ocean sediments using rock magnetism and geochemistry to trace dust provenance and to reconstruct source area humidity evolution. Combined relative paleointensity dating and tephrochronology constrain the bottom age of the core to similar to 78 ka. The Taklimakan Desert is identified as the dominant dust source, and the hematite-to-goethite ratio (Hm/Gt) of dust is used as a source area humidity proxy. Hm/Gt is higher in dry stages and lower during wet stages on precession timescales, and also captures signals due to Heinrich and Dansgaard-Oeschger events. On orbital timescales, precession can modulate humidity variations in the Taklimakan Desert by shifting the southern branch of the westerly axis. The westerly jet contracts and flows prevalently through the Taklimakan Desert when the precession index is low and carries increased precipitation. On millennial timescales, westerly displacement was influenced by Atlantic Meridional Overturning Circulation variations. Humid events at the MIS 4-3 transition and the last deglaciation coincided with rapid cold-to-warm transitions when increased mountain glacier meltwater enhanced runoff, resulting in sustained regional humid conditions.

Large igneous provinces (LIPs) in the Pacific Ocean were predominantly emplaced during the Early Cretaceous, which has been suggested to result from either return flow due to increased slab flux, a superplume or plume-ridge interaction. Here we present palaeogeographically constrained mantle flow modelling that links subduction, plume activity and ridge evolution to investigate how the interplay between these processes controls radial heat advection and LIP eruption. Our models show relatively stable hot upwellings in the central Pacific between similar to 165 and 80 Ma, rooted above lower-mantle hot structures, with peak upwelling intensity around 130-125 Ma driven by enhanced slab flux acting on inherited deep thermal structure. Migrating spreading ridges intersected these upwellings at similar to 145-120 Ma and slowed down temporarily when radial heat advection was large, resulting in intense LIP eruptions. The subsequent decline in LIP activity is attributed to a combination of reduced upwelling strength and rapid ridge migration away from the central Pacific. Our results highlight that radial heat advection intensity is jointly controlled by slab flux and inherited mantle structure, while the interaction of migrating ridges with upwellings is critical to trigger mantle melting and LIP eruption.

Located in the collision zone between the Eurasian and Philippine Sea plates, the Philippine Mobile Belt (PMB), with intense earthquakes and volcanism, is a typical area for the study of plate subduction, island arc accretion, and microplate amalgamation. However, due to the complexity of tectonic history of this region, the existing studies are still deficient in understanding the crustal structure and deep dynamics. To address this, we develop a new improved crustal thickness model for the Philippine Archipelago using EIGEN-6C4 gravity data and advanced inversion methodology. Integration of microplate boundary kinematics and active fault systems permits division of the PMB into nine discrete microplates. Our study shows that pronounced isostatic disequilibrium along the Manila Trench, Philippine Trench, and Philippine Fault, indicating active lithospheric adjustment. The crustal thickness of the PMB shows significant spatial heterogeneity, revealing the existence of anomalous crustal thickening spatially correlated with volcanic chains flanking the main Philippine Fault Zone. We propose a dual-mechanism crustal thickening model driven by both multi-stage accretionary processes and deep magma underplating, offering new insights into the crust-mantle interactions governing the Philippine orogenic system and microplate geodynamics.

High chlorinity in the pore water within the gas hydrate-bearing sediments indicates recent or ongoing formation of gas hydrate, but its role in reflecting and assessing gas hydrate and cold seep system activity remains unclear. This study categorizes active gas hydrate systems into buried recent active gas hydrate system, active cold seep, and paleo-cold seep, based on high chlorinity locations, gas hydrate-bearing sediment distribution, and seafloor characteristics. Focusing on gas hydrate drilling sites with high chlorinity in the northern South China Sea, we used well log data, chlorinity, and a one-dimensional decay model to constrain the gas hydrate formation times. Results show that the active cold seep at Site GMGS6-W01 in the Qiongdongnan Basin, marked by gas plumes and mussels on the seabed, is the youngest, estimated at 0.5 to 2 thousand years old, followed by buried recent active gas hydrate system at Sites GMGS3-W18&19 and GMGS4-SC01&SC02 in the Pearl River Mouth Basin, which is about 19-29 thousand years old. In contrast, the paleo-cold seeps at Site GMGS2-W16 in the Taixinan Basin have the widest age range, with potential multiple activities occurring between 2 and 39 thousand years ago. Gas sources and migration pathways are the main geological controls on the variation of gas fluxes, which together with reservoirs, influence gas hydrate accumulation and morphology. Active gas hydrate systems are controlled by fluid migration structures such as faults, gas chimneys, diapirs, and hydrate chimneys, as well as recent rapid sedimentation events. Paleo-cold seeps will form when new clay sediments cover the existing cold seeps. Our results emphasize the importance of high chlorinity in analyzing the accumulation and evolution of active gas hydrate systems, aiding in understanding gas hydrate distribution and the associated free gas conversion.

Cerium isotopes (δ142/140Ce) are a promising proxy for reconstructing the evolution of Earth redox conditions over geological time, but their fractionation in anoxic-sulfidic environments remains poorly understood. Here, we present the first δ142/140Ce data from anoxic-sulfidic sediments of the South China Sea. Our results show that no significant Ce anomalies (0.92–1.01) are observed in anoxic-sulfidic sediments. In addition, the δ142/140Ce values (−0.007‰–0.070‰) were found to be lower than those observed in oxic environments, yet comparable to values of the upper continental crust. This phenomenon may be attributed to the reductive dissolution of Fe and Mn (oxy)hydroxides in a reducing environment, resulting in the release of heavy 142Ce into the water. Additionally, Ce is predominantly dissolved and rarely occurs in the sediments. These observations indicate that the Ce in anoxic-sulfidic sediments predominantly originates from terrigenous detritus supply, exhibiting a limited authigenic component, and the δ142/140Ce values predominantly reflect the terrigenous detritus value. Consequently, although Ce isotopes can distinguish between oxic and anoxic-sulfidic conditions, their quantitative application as a paleoredox proxy in sulfidic environments requires direct constraints on authigenic Ce isotopic compositions.