Global and Planetary Change最新文献_第8页

Precession-dominated summer insolation forcing of East Asian monsoon precipitation since 1.2 Ma: Insights from the Weihe Basin, Central China 1.2 Ma以来以岁差为主导的东亚季风降水夏季日照强迫：来自渭河盆地的启示

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2026-01-03 DOI: 10.1016/j.gloplacha.2026.105281

Xuke He , Yougui Song , Yue Li , Jianhong Xu , Xiaofen Fu , Huifang Liu , Qingliang Wang , Yixiao Han

The Asian monsoon is crucial for sustaining billions of people, yet its geological history, primary drivers, and mechanisms remain contentious. To explore the potential driving mechanisms of East Asian summer monsoon (EASM) precipitation since the Early Pleistocene, we here present data from a 272-m-long core of Quaternary lacustrine–fluvial–aeolian sediments from the Weihe Basin in central China. The chronology of the core is established through magnetostratigraphy and tie-point matching with speleothem oxygen isotope (δ¹⁸O) curves. Lithofacies and geochemical profiles reveal that the core records a sedimentary succession from lacustrine through fluvial to aeolian depositional environments since 1.18 Ma. End-member (EM) modeling of lacustrine deposits shows that the transport and deposition of coarse EM3, EM4, and EM5 components are linked to vigorous nearshore hydrodynamics. Consequently, the summed proportion of these three EMs serves as an indicator of monsoon-induced paleolake transgressions and regressions. Reduced precipitation causes lake contraction, and the development of littoral lake sub-facies enriched in coarse EM components. Hydrodynamic sorting, modulated by catchment hydrology, imparted a precession signal to lacustrine bulk-sediment XRF element intensities. On orbital timescales, EASM precipitation variations are governed by precession-dominated boreal-summer insolation. Featuring a robust chronology and sensitive response of lacustrine proxies to precipitation, our findings confirm that insolation forcing fundamentally governs precipitation patterns in East Asia.

亚洲季风对维持数十亿人的生计至关重要，但其地质历史、主要驱动因素和机制仍存在争议。为了探讨早更新世以来东亚夏季风（EASM）降水的潜在驱动机制，我们利用了中国中部渭河盆地第四纪湖-河-风成沉积物的272米长的岩心数据。通过磁地层学和与岩心氧同位素（δ18O）曲线的结合点拟合，确定了岩心的年代学。岩石相和地球化学剖面显示，该岩心记录了1.18 Ma以来湖泊-河流-风成沉积环境的沉积序列。湖泊沉积物的端元（EM）模拟表明，粗EM3、EM4和EM5组分的搬运和沉积与剧烈的近岸水动力有关。因此，这三个em的总和比例可以作为季风引起的古湖泊海侵和回归的指标。降水减少导致湖泊收缩，形成富含粗EM组分的滨海湖泊亚相。受流域水文调节的水动力分选为湖泊体沉积物XRF元素强度提供了进动信号。在轨道时间尺度上，东亚地区降水变化受进动主导的寒夏日晒的支配。具有强大的年代学和湖泊代用物对降水的敏感响应，我们的研究结果证实了日照强迫从根本上控制了东亚的降水模式。

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引用次数: 0

Reconstruction of last millennium sea surface temperature on 1° grid using a random forest algorithm 用随机森林算法重建1°网格上近千年海面温度

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2026-01-03 DOI: 10.1016/j.gloplacha.2025.105279

Simon L.L. Michel , Didier Swingedouw , Juliette Mignot

Climate models and theoretical evidence show that the ocean drives climate from sub-decadal to centennial timescales through a variety of processes and their interactions. The range of direct climate observations, arelhowever, is too short to understand the exact role of the ocean in shaping observed and future climate variability on top of anthropogenic climate change. In the present study, we use a large set of paleoclimate records combined with a random forest algorithm to reconstruct a gridded dataset of sea surface temperatures since 850 C.E. to provide a better framework for the study of ocean surface variability. In line with modeling and paleodata studies, our reconstruction suggests that natural climate forcings have importantly influenced the last millennium climate variability. Our reconstruction also suggests that North Atlantic SST multidecadal variability influences Pacific SST on decadal timescales. However, the latter result is shown to be strongly dependent on background climate conditions. This new reconstruction offers a useful resource for testing the capabilities of climate models to reproduce the linkages between Atlantic and Pacific as well as the response to external forcings.

气候模式和理论证据表明，海洋通过各种过程及其相互作用驱动着从次年代际到百年代际的气候。然而，直接气候观测的范围太短，无法理解海洋在人为气候变化之外塑造已观测到的和未来的气候变率方面的确切作用。本研究利用大量的古气候记录，结合随机森林算法重建了850 C.E.以来的海洋表面温度网格数据集，为研究海洋表面变率提供了一个更好的框架。与模拟和古数据研究一致，我们的重建表明，自然气候强迫对过去一千年的气候变率有重要影响。我们的重建也表明北大西洋海温的多年代际变化在年代际时间尺度上影响太平洋海温。然而，后一种结果在很大程度上取决于背景气候条件。这种新的重建为测试气候模式再现大西洋和太平洋之间的联系以及对外部强迫的反应的能力提供了有用的资源。

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引用次数: 0

Holocene climate optimum moisture variability in the monsoon marginal zone of northern China revealed by multi-proxy stalagmite records 多代石笋记录揭示的中国北方季风边缘区全新世气候最适湿度变率

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-30 DOI: 10.1016/j.gloplacha.2025.105278

Shouyi Huang , Yanjun Cai , Gang Xue , Xinhui Zhang , Mei He , Ruoxin Li , Yingying Wei , Le Ma , Xing Cheng , Haiwei Zhang , Hai Cheng

Reconciling the diverse climate responses of various geological archives poses a challenge for a comprehensive understanding of the Holocene climate change in East Asia. Here, we present multi-proxy records of two precisely dated stalagmites from the northeastern Chinese Loess Plateau. A comparative analysis reveals that the main depositional period (∼9.6–5.9 ka BP) of one stalagmite directly corresponds to the Holocene Climate Optimum (HCO) in northern China. The stalagmite δ¹⁸O exhibits a quasi-500-year cyclicity throughout the HCO, which aligns with other records from the North Atlantic, East Asia, and Mediterranean during the cycle from ∼8.3 to 7.8 ka BP, likely reflecting the 8.2 ka event's imprint. Meanwhile, divergent phase relationships occurred during other intervals, indicating regionally distinct responses to solar-driven coupled ocean-atmosphere oscillations. Furthermore, multiple hydroclimate proxies and the stalagmite growth rate from the same stalagmite reveal a shift in the precipitation regimes, manifested as the rainy season extending from summer to autumn after ∼7.8 ka BP. Changes in the position and intensity of the subtropical westerly jet may drive this shift.

协调各种地质档案的不同气候响应对全面认识东亚全新世气候变化提出了挑战。本文报道了中国东北黄土高原两种石笋的多代用记录。对比分析表明，某石笋的主要沉积期（~ 9.6 ~ 5.9 ka BP）与中国北方全新世气候适宜期（HCO）直接对应。石笋δ18O在整个HCO中表现出准500年的周期，这与北大西洋、东亚和地中海的其他记录在~ 8.3 ~ 7.8 ka BP的周期内一致，可能反映了8.2 ka事件的印记。与此同时，在其他时段出现了发散的相位关系，表明对太阳驱动的海洋-大气耦合振荡的区域响应不同。此外，多种水文气候指标和来自同一石笋的石笋生长速率揭示了降水制度的变化，表现为在~ 7.8 ka BP之后，雨季从夏季延长到秋季。副热带西风急流的位置和强度的变化可能驱动这种转变。

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引用次数: 0

Oceanic deoxygenation linked to enhanced water column stratification in the eastern Tethys during Cretaceous Oceanic Anoxic Event 2 白垩纪海洋缺氧事件2期间，特提斯东部的海洋脱氧与水柱分层增强有关

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-29 DOI: 10.1016/j.gloplacha.2025.105270

Yu Liang , Yong-Xiang Li , Hongxuan Lu , Huanye Wang , Cece Wang , Cheng Quan , Weiguo Liu , Mei-Fu Zhou , Zhonghui Liu

The mid-Cretaceous Oceanic Anoxic Event 2 (OAE2, ∼94 Ma) stands as a prominent deep-time analogue for understanding global oceanic redox variations in response to major environmental perturbations. However, the mechanisms driving oceanic redox evolution in the eastern Tethys during OAE2, particularly the influence of water column stratification, remain poorly investigated. In this study, we analyze the connections between oceanic redox, stratification, and productivity changes in the eastern Tethys during OAE2 using biomarker records of glycerol dialkyl glycerol tetraethers (GDGTs) and n-alkanes from the Gongzha section, southern Tibet. Our results reveal pronounced increases in oceanic deoxygenation and stratification, alongside reduced productivity, through the carbon isotope stage C4, the main phase of OAE2 following the initial perturbation and prior to the recovery. Combining these findings with existing geological data from the Gongzha section, we infer that enhanced water column stratification may have driven the oceanic deoxygenation by diminishing ocean-atmosphere exchange in the eastern Tethys during OAE2. This mechanism differs from that previously observed in the circum-proto-North Atlantic, where increased productivity and associated enhancement in the organic remineralization may have triggered the marine anoxia. By providing biological constraints, our study indicates the dominant role of water column structure in shaping redox evolution in the eastern Tethys, highlighting distinct regional controls on oceanic redox evolution during OAE2.

中白垩纪海洋缺氧事件2 （OAE2, ~94 Ma）是了解全球海洋氧化还原变化对主要环境扰动响应的重要深时间模拟。然而，在OAE2期间，特提斯东部海洋氧化还原演化的驱动机制，特别是水柱分层的影响，仍然缺乏研究。本文利用藏南贡扎剖面的甘油二烷基甘油四醚（GDGTs）和正构烷烃的生物标志物记录，分析了OAE2期间特提斯东部海洋氧化还原、分层和生产力变化之间的联系。我们的研究结果表明，在碳同位素阶段C4 （OAE2在初始扰动之后和恢复之前的主要阶段），海洋脱氧和分层显著增加，同时生产力降低。结合公闸剖面已有的地质资料，我们推测在OAE2期间，特提斯东部水柱分层增强可能通过减少海气交换来驱动海洋脱氧。这一机制与之前在北大西洋周围观察到的机制不同，在北大西洋周围，生产力的提高和有机再矿化的相关增强可能引发了海洋缺氧。通过提供生物学约束，我们的研究表明水柱结构在塑造特提斯东部氧化还原演化中起主导作用，突出了OAE2期间海洋氧化还原演化的明显区域控制作用。

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引用次数: 0

Small-scale high-temperature metamorphic core-complexes: From nappe stacking to orogen parallel extension and subsequent thrusting in the Megina dome of North Dobrogea orogen 小型高温变质岩心杂岩：从推覆堆积到造山带平行伸展及其后的逆冲

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-29 DOI: 10.1016/j.gloplacha.2025.105276

Andreea Marza-Ene , Liviu Matenco , Hannah Pomella , Vlad Victor Ene , Ioan Munteanu , Anneke Royakkers

Orogenic extension has been demonstrated to generate lower crustal exhumation observed in metamorphic core complexes. Observations and modelling have shown that orogen parallel extensional domes are challenging to constrain due to the superposition with coeval or subsequent geodynamic processes, such as orogenic thrusting, magmatism, or the evolution of subducted slabs. We utilise outcrop and micro scale observations to structurally quantify the original nappe stack burial and extensional exhumation structures of one such dome in the Măcin unit of the European North Dobrogea orogen. The results demonstrate an initial top to NE nappe stacking associated with the previously defined Late Carboniferous – Permian burial metamorphism, which affected a mafic protolith and its sedimentary cover. This burial was followed by Triassic extensional exhumation, retrograde metamorphism, magmatism and top to SE ductile shearing, which created a newly identified major detachment and orogen-parallel extensional dome. The kinematic study is furthermore complemented by a low-temperature fission track thermochronology performed to discriminate the extensional exhumation from the effects of subsequent thrusting. The thermochronology demonstrates that the Triassic extensional dome was subsequently affected by a Jurassic–Early Cretaceous exhumation, which is a novel quantification of the previously defined Cimmerian thrusting. Our results infer a new interpretation of the Măcin unit as a Palaeotethys ophiolitic suture zone, which contains a typical Hercynian metamorphic core-complex of relatively small dimensions. When compared with other similar larger structures observed elsewhere, our results show that small-scale orogen-parallel extensional domes can also develop at high temperatures during or after the main stage of nappe stacking metamorphism.

在变质岩心杂岩中，造山带伸展作用已被证实产生下地壳掘出。观测和模拟表明，由于与同期或随后的地球动力学过程（如造山逆冲、岩浆活动或俯冲板块的演化）的叠加，造山带平行伸展穹丘很难约束。我们利用露头和微观尺度的观测，对欧洲北多布罗格造山带马利辛单元的一个这样的巨丘的原始推覆层埋藏和伸展掘出构造进行了结构量化。研究结果表明，晚石炭世—二叠世埋藏变质作用影响了基性原岩及其沉积盖层，形成了由上至北东向推覆体的初始叠加。三叠纪伸展掘出、逆变质作用、岩浆作用和顶部至东南韧性剪切作用，形成了新发现的大拆离和与造山带平行的伸展丘。低温裂变径迹热年代学进一步补充了运动学研究，以区分伸展发掘和随后的逆冲作用。热年代学表明，三叠纪伸展丘随后受到侏罗纪-早白垩世掘出的影响，这是对先前定义的西元叠世逆冲构造的一种新的量化。我们的研究结果推断出一种新的解释，即马利辛单元是一个古特提斯蛇绿岩缝合带，其中包含一个典型的海西期相对较小的变质核杂岩。与其他地区观测到的类似大型构造相比，我们的研究结果表明，小规模的平行造山带伸展穹丘也可以在推覆堆积变质主阶段或之后的高温下发育。

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引用次数: 0

Spatial heterogeneity of wildfire in the East Asian monsoon region on a glacial-interglacial timescale 东亚季风区冰期-间冰期野火的空间异质性

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-27 DOI: 10.1016/j.gloplacha.2025.105277

Yanxia Liang , Xin Zhou , Tao Zhan , Ye Yang , Xiaoyan Liu , Yong Luo , Yufeng Yuan , Enbao Wang

Understanding the responses of wildfires to long-term climate variability is critical for improving fire management strategies and maintaining ecological stability. However, the spatial heterogeneity and drivers of wildfires in the East Asian monsoon (EAM) region on orbital timescales remain poorly constrained. In this study, wildfire dynamics across the last five glacial-interglacial cycles were determined based on a ∼ 480 kyr wildfire history reconstructed from black carbon (BC) records in the Huangshan loess-paleosol sequence in northeastern China. The results revealed substantial glacial-interglacial cycles in northeastern China, with more intense fires during interglacials than glacials. Comparative analysis with other wildfire records revealed notable spatial heterogeneity of wildfires across the EAM region on the glacial-interglacial timescale. Wildfires in the eastern East Asian monsoon (EEAM) region were more active during interglacials, likely due to higher temperatures and greater biomass availability. Conversely, those in the western East Asian monsoon (WEAM) region were more frequent during glacials because of fuel desiccation caused by reduced precipitation. Overall, the large-scale spatial precipitation pattern, which gradually decreased from southeast to northwest in the EAM region, may serve as the core driver of wildfire spatial heterogeneity. Under future global warming, the EEAM region will likely face elevated wildfire risks and should be prioritized for fire prevention.

了解野火对长期气候变率的响应对于改善火灾管理策略和维持生态稳定至关重要。然而，在轨道时间尺度上，东亚季风地区野火的空间异质性和驱动因素仍然缺乏明确的认识。本研究基于中国东北黄山黄土-古土壤序列黑碳（BC）记录重建的野火历史，确定了近5个冰期-间冰期的野火动态。结果表明，中国东北地区存在大量的冰期-间冰期旋回，间冰期的火灾强度大于冰期。与其他野火记录的对比分析显示，EAM地区野火在冰期-间冰期时间尺度上具有显著的空间异质性。东亚季风（EEAM）地区的野火在间冰期更为活跃，可能是由于较高的温度和更大的生物量可用性。相反，由于降水减少导致燃料干燥，东亚季风（WEAM）地区在冰期更为频繁。总体而言，EAM区域从东南向西北逐渐减少的大尺度空间降水格局可能是野火空间异质性的核心驱动因素。在未来全球变暖的背景下，EEAM地区可能面临更高的野火风险，应优先考虑防火。

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引用次数: 0

Deformation dynamics of the retro-wedge foreland: Seismic interpretation and numerical modeling study of the Llanos Basin, Colombia 楔后前陆变形动力学：哥伦比亚Llanos盆地地震解释与数值模拟研究

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-26 DOI: 10.1016/j.gloplacha.2025.105274

Michal Nemčok , Steve A. Hermeston , Andreas Henk , Andres Mora , Camilo Higuera , Mauricio Parra , Samuel Rybár , Lucia Ledvényiová

Combining reflection seismic interpretation with numerical modeling, this paper studies the deformation dynamics of the foreland plate overridden by the retro-wedge of an advancing subduction zone. The post-middle Eocene Llanos foreland basin serves as the natural laboratory. The reflection seismic interpretation identifies five elongated clusters of flexure-driven normal-faults, centered on the forebulge axis. Clusters have different stratigraphies of their syn-tectonic strata. They are located foreland-ward of thickness maxima of the coeval foreland basin fill. Normal faults are mostly planar, steep and die out with depth without being detached. Both fault clusters and infill thickness maxima are characterized by the SW-to-NE migration in time. Those sub-sets of normal faults, which are adjacent to retro-wedge, underwent tectonic inversion. They became reverse faults in a short time interval, likely less than 1-2 million years. The modeling demonstrates that the inversion requires a stress regime with sub-horizontal σ₁ stress affecting the foreland crust located between the forebulge and retro-wedge. This regime does not occur when the foreland plate is only loaded by the retro-wedge and foreland basin fill. It requires both vertical loads plus horizontal compression affecting the foreland plate. The modeling also indicates that both aforementioned loading scenarios result in the development of forebulge axis-centered clusters of flexure-driven normal faults. The modeling also indicates that the orogen-parallel Jurassic – Early Cretaceous rift-related crustal thinning zone located in the foreland plate results in its narrow flexure mode. Instead, the lack of crustal thinning results in a broad flexure mode of the foreland plate.

本文将反射地震解释与数值模拟相结合，研究了前陆板块在俯冲带后向楔体覆盖下的变形动力学。中始新世后的拉诺斯前陆盆地是天然的实验室。反射地震解释确定了以前隆起轴为中心的五个弯曲驱动的细长正断层簇。丛集具有不同的同构造地层。它们位于同时期前陆盆地充填厚度最大值的前陆方向。正断层多呈平面状，坡度大，随深度逐渐消失，不分离。断层簇和充填厚度最大值在时间上都表现出西南向北东向的偏移特征。与逆楔相邻的正断层亚群经历了构造反转。它们在很短的时间间隔内变成了逆断层，可能不到1- 200万年。模拟结果表明，该反演需要一个亚水平σ1应力区，该应力区作用于前陆地壳，位于前隆起和后楔之间。当前陆板块仅受后倾楔体和前陆盆地充填作用时，这种状态不会发生。它需要影响前陆板块的垂直载荷和水平压缩。模拟结果还表明，上述两种加载情景均导致前隆起轴向正断层群的发育。模拟还表明，位于前陆板块的与造山带平行的侏罗纪-早白垩世与裂谷有关的地壳减薄带导致其狭窄的弯曲模式。相反，缺乏地壳减薄导致了前陆板块的广泛弯曲模式。

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引用次数: 0

Four decades of glacier changes in Karzok, Ladakh regulated by climatic and non-climatic drivers (1980–2023)

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-24 DOI: 10.1016/j.gloplacha.2025.105275

Mohit Prajapati , Purushottam Kumar Garg , Sandipan Mukherjee , Supratim Guha , Ashutosh Tiwari , Ajay Kumar Taloor

Long-term glacier monitoring provides critical insights into climate variability. This study presents a multi-temporal inventory for the Karzok Range, Ladakh, covering five massifs (Rulung, Chamser-Lungser, Gyama, Spangnak, and Pologongka) for the years 1980, 1990, 2000, 2014, and 2023; evaluates changes in glacier extent and assesses the influence of climatic (temperature and precipitation) and non-climatic (size, compactness, altitude, slope and aspect) factors on these changes. The Karzok region harbors 276 glaciers covering an area of 151.4 ± 9.3 km² which are predominantly small (71 %; <0.5 km²). These originate (6632 m a.s.l.) as well as terminate (5349 m a.s.l.) at higher altitudes possessing mean altitude of 5922 m a.s.l. and characterized by relatively steep slope (25.2°). During 1980–2023, total deglaciation was 25.6 % (from 169.4 ± 7.7 km² to 125.4 ± 2.5 km²), with the greatest loss in Gyama (35.2 %) and the least in Chamser-Lungser (17.9 %). Glaciers with smaller size, lower mean elevation, narrower altitude bands, and steeper slopes showed higher deglaciation, while those at higher elevations with broader altitude ranges were more resilient. The aspect had limited influence, though south- and east-slopes were more deglaciation-prone. Compactness ratio (>0.6) exerted negligible influence on deglaciation owing to predominance of low branching. Climate analysis (1950–2023) revealed significant warming (0.22 °C decade⁻¹), especially post-1980, with no consistent precipitation trend, signifying warming to be the primary driver of deglaciation. Overall, Karzok glaciers are in depletion phase, with pronounced intra-regional variability driven by topography. Ongoing and projected warming will likely speed up deglaciation, highlighting the need for systematic research to better manage Ladakh's water resources.

长期的冰川监测提供了对气候变化的重要见解。卡尔佐克地区有276条冰川，面积151.4±9.3平方公里，主要是小冰川（71%;<；0.5平方公里）。它们起源于（海拔6632米）和终止于（海拔5349米）较高的海拔，平均海拔5922米，坡度相对陡（25.2°）。1980—2023年，冰川消融总量为25.6%（从169.4±7.7 km2减少到125.4±2.5 km2），其中甲玛冰川消融最大（35.2%），Chamser-Lungser冰川消融最少（17.9%）。尺寸越小、平均高程越低、海拔带越窄、坡度越陡的冰川消冰率越高，而海拔越高、海拔范围越宽的冰川复原力越强。虽然南坡和东坡更容易发生冰川消融，但坡向的影响有限。密实比（>0.6）对消冰作用的影响可以忽略不计，主要表现为低分枝。气候分析（1950-2023）显示显著变暖（0.22°C 10−1），特别是1980年以后，降水趋势不一致，表明变暖是消冰的主要驱动因素。总体而言，卡尔佐克冰川处于枯竭阶段，地形驱动的区域内变化明显。

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引用次数: 0

Sediment melting during subduction initiation: Evidence of mantle-hosted S-type granitoids in the Neoproterozoic Fuchuan Ophiolite 俯冲起始期沉积物熔融：新元古代富川蛇绿岩中幔载s型花岗岩的证据

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-24 DOI: 10.1016/j.gloplacha.2025.105272

Si-Fang Huang , Wei Wang , Andrew C. Kerr , Peter A. Cawood , Guimei Lu

The mechanisms and geodynamic significance of sediment recycling in subduction zones remain intensely controversial in Precambrian geology. This study reports a suite of Precambrian sediment-derived felsic intrusions preserved within an exhumed mantle peridotite of a supra-subduction zone in South China. These felsic rocks intruded into the peridotite of the Fuchuan Ophiolite show U-Pb ages of 846–837 Ma, coinciding with the dating of ca. 848–820 Ma crustal section rocks of the ophiolite, implying their generation during slab subduction rather than later obduction. Petrography, zircon O isotopic and trace elemental signatures of the Fuchuan mantle-hosted granitoids indicate S-type affinity. Integrated O (δ¹⁸O = 7.5 ‰ to 11.3 ‰), Hf (ɛ_Hf(t) = −3.8 to +6.9) and Nd (ɛ_Nd(t) = −2.2 to −0.4) isotopic compositions, coupled with inherited zircon ages and whole-rock geochemistry, collectively suggest derivation from a continental margin sediment protolith. Geochemical analyses and pseudosection modeling reveal partial melting of subducted sediment at 650–790 °C and < 4 kbar (∼12–15 km). This condition of melting is atypical in a mature subduction channel, but is plausible during the initiation phase of subduction. Consequently, the mantle-hosted S-type intrusions formed during slab subduction may represent a proxy for subduction initiation. In contrast to the formation depth (< 14 kbar; depths <45 km) of Phanerzoic mantle-hosted leucogranitoids, sediment-derived melt transport from subducting slabs during the Neoproterozoic occurred at substantially shallower depths, suggesting that the Neoproterozoic era may witness the reoperating of modern-style plate tectonics after Earth's middle age, occurring under elevated mantle potential temperatures relative to present-day conditions.

俯冲带沉积物再循环的机制和地球动力学意义在前寒武纪地质学中一直存在激烈的争议。本文报道了一套前寒武纪沉积衍生的长英质侵入体保存在中国南方一个超俯冲带的地幔橄榄岩中。这些侵入富川蛇绿岩橄榄岩的长英质岩石U-Pb年龄为846 ~ 837 Ma，与蛇绿岩约848 ~ 820 Ma的地壳剖面岩石年龄一致，表明其形成于板块俯冲而非后期的逆冲。富川幔源花岗岩的岩石学、锆石O同位素和微量元素特征显示出s型亲和关系。综合O （δ18O = 7.5‰~ 11.3‰）、Hf（ν Hf(t) =−3.8 ~ +6.9）和Nd（ν Nd(t) =−2.2 ~−0.4）同位素组成，结合继承的锆石年龄和全岩地球化学特征，表明其来源于大陆边缘沉积原岩。地球化学分析和伪剖面模拟显示，在650-790°C和<； 4 kbar （~ 12-15 km）处，俯冲沉积物部分熔融。这种熔融条件在成熟的俯冲通道中是不典型的，但在俯冲的起始阶段是可能的。因此，在板块俯冲过程中形成的幔源s型侵入体可能代表了俯冲起始的标志。与显生宙幔载浅花岗岩类的形成深度（14 kbar；深度45 km）相比，新元古代俯冲板块的沉积物衍生熔融运输发生在较浅的深度，这表明新元古代可能见证了地球中世纪之后现代风格板块构造的再操作，发生在相对于当今条件的更高的地幔潜在温度下。

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引用次数: 0

Affinity and underestimated Precambrian crustal growth in the Central Asian Orogenic Belt: Evidence from the North Alxa Block 中亚造山带前寒武纪地壳生长的亲和与低估：来自北阿拉善地块的证据

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-23 DOI: 10.1016/j.gloplacha.2025.105273

Xiaochen Zhao , Yazhuo Niu , Jianqiang Wang , Donghai Zhang , Bo Song

The Central Asian Orogenic Belt (CAOB) encompasses numerous Precambrian microcontinents whose tectonic affinity and growth models have garnered significant attention, due to their crucial role in understanding the CAOB's tectonic architecture and orogenic evolution. However, persistent controversies remain regarding these fundamental issues. To address these uncertainties, we focus on the North Alxa Block (NAB), a major Precambrian microcontinent in the southern CAOB, and present integrated U-Pb-Hf isotopic data from detrital zircons spanning a billion-year sedimentary record. Detrital zircon U-Pb geochronology and Hf isotopic analyses reveal systematic age populations: Archean-Proterozoic (peaks at 2586–2438, 1786–1714, 1528–1413 Ma) and Paleozoic (peaks at 473–425, 292–266 Ma), with corresponding ε_Hf(t) values showing distinguishable ranges and evolutionary trends. The detrital zircon U-Pb ages and Hf isotopic compositions reveal a multi-stage paleogeographic evolution, evidenced by provenance shifts. Furthermore, the strong correlations among rock assemblages, magmatic events, detrital zircon age distributions, and Hf isotopic compositions collectively indicate that the NAB and other microcontinents constitute an integrated banded Precambrian juvenile continental terrane accreted to the margins of the Baltica–Laurentia cratons during the Middle Mesoproterozoic, substantiating previous studies. The step-like crustal growth and reworking patterns of the NAB demonstrate significant Precambrian crustal growth, comparable to that of other CAOB microcontinents. The crustal growth curve of the NAB indicates previously underestimated crustal growth (increment of ∼88 %) in the Proterozoic, and extensive reworking since 500 Ma (increment of ∼85 %). Combined with the similar prominent Proterozoic crustal growth recorded in other microcontinents of the CAOB, these findings indicate global-scale tectonic control during this period.

中亚造山带（CAOB）包含了大量的前寒武纪微大陆，它们的构造亲和性和生长模式在了解中亚造山带的构造结构和造山演化中起着至关重要的作用，因此受到了广泛的关注。然而，关于这些基本问题的争论仍然存在。为了解决这些不确定性，我们以华北地区南部一个主要的前寒武纪微大陆——北阿拉xa地块（NAB）为研究对象，对跨越10亿年沉积记录的碎屑锆石进行了U-Pb-Hf同位素的综合分析。碎屑锆石U-Pb年代学和Hf同位素分析揭示了太古宙-元古代（峰值在2586 ~ 2438,1786 ~ 1714,1528 ~ 1413ma）和古生代（峰值在473 ~ 425,292 ~ 266 Ma）的系统年龄群，相应的εHf(t)值具有明显的范围和演化趋势。碎屑锆石U-Pb年龄和Hf同位素组成揭示了一个多阶段的古地理演化过程，并以物源转移为证据。此外，岩石组合、岩浆事件、碎屑锆石年龄分布和Hf同位素组成的强相关性共同表明，NAB和其他微大陆构成了一个完整的带状前寒武纪幼年大陆地体，在中元古代沉积到波罗的海-劳伦提亚克拉通边缘，证实了前人的研究。与其他CAOB微大陆相比，NAB的阶梯状地壳生长和改造模式显示出显著的前寒武纪地壳生长。NAB的地壳生长曲线显示了之前被低估的元古代地壳生长（增量为~ 88%），以及500 Ma以来的广泛改造（增量为~ 85%）。结合CAOB其他微大陆类似的元古代地壳生长记录，这些发现表明这一时期存在全球范围的构造控制作用。

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引用次数: 0