Earth and Planetary Science Letters最新文献_第3页

Triple oxygen isotope signatures of cherts record pore-fluid composition and temperature across the opal-CT to quartz transition 燧石的三氧同位素特征记录了整个蛋白石-石英过渡过程中的孔隙流体组成和温度

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-04-01 Epub Date: 2026-02-03 DOI: 10.1016/j.epsl.2026.119889

Oskar Schramm , Katharina Ebert , Patrick J. Frings , Andreas Pack , Tommaso Di Rocco , Volker Karius , Nils Keno Lünsdorf , Dieter Korn , Daniel Herwartz , Michael Tatzel

Sedimentary chert is the diagenetic end-product of amorphous silica that first transforms to opal-cristobalite/tridymite (CT) and subsequently to microcrystalline quartz via dissolution and reprecipitation reactions. The ¹⁸O/¹⁶O and ¹⁷O/¹⁶O ratios (i.e. triple oxygen isotope composition, δ¹⁸O, Δ’¹⁷O) of cherts record equilibration with the pore fluids at the diagenetic temperatures prevalent during the opal-CT to quartz transition. Pore fluid oxygen isotope gradients emerge when secondary minerals, e.g. clay minerals form during burial. Here, we demonstrate that chert triple oxygen isotope compositions not in equilibrium with modern like seawater can be explained by changes in pore water δ¹⁸O and Δ’¹⁷O without invoking any alteration or different paleo-seawater. We demonstrate this using a suite of Carboniferous cherts that we collected from the same stratigraphic level at five locations in the Rhenish Massif, Germany, spanning a range of inferred burial rates. The precursor sediments were deposited in the marine Rhenohercynian Basin and were subject to peak diagenetic temperatures of up to 279 ± 37 °C upon folding and thrusting. Their triple oxygen trajectory cannot be explained by any realistic paleo-seawater composition. Using our numerical silica diagenesis model, we find that the chert isotope signatures are explained by a formation temperature between 20–35 °C and a pore fluid composition of -7 to -14‰ δ¹⁸O consistent with a pore fluid gradient of -13.5 ‰ km^-1 across the Rhenohercynian Basin. This suggests that triple oxygen isotope compositions of chert systematically record near-surface conditions and therefore represent a valuable resource for paleoenvironmental research.

沉积燧石是无定形二氧化硅的成岩最终产物，它首先转化为蛋白石-方英石/钇石（CT），随后通过溶解和再沉淀反应转化为微晶石英。燧石的18O/16O和17O/16O比值（即三氧同位素组成Δ 18O， Δ’17O）记录了在蛋白石- ct -石英转变过程中普遍存在的成岩温度下与孔隙流体的平衡。次生矿物如粘土矿物在埋藏过程中形成时，孔隙流体氧同位素梯度就会出现。研究结果表明，与现代海水不平衡的燧石三氧同位素组成可以用孔隙水Δ 18o和Δ’17O的变化来解释，而不需要任何蚀变或不同的古海水。我们用一套石炭纪燧石来证明这一点，这些燧石是我们在德国莱茵山脉的五个地点从相同的地层水平收集的，跨越了一系列推断的埋葬率。前体沉积于海相雷诺西期盆地，在褶皱和逆冲作用下，成岩温度最高可达279±37℃。它们的三氧轨迹不能用任何现实的古海水成分来解释。利用数值硅石成岩模型，我们发现石英同位素特征可以解释为地层温度在20-35℃之间，孔隙流体组成为-7 ~ -14‰δ18O，与整个雷诺西期盆地的孔隙流体梯度为-13.5‰km-1相一致。这表明燧石的三氧同位素组成系统地记录了近地表条件，因此为古环境研究提供了宝贵的资源。

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引用次数: 0

Multi-pulse and crystal-laden emplacement of the Tunnel Dike: implications for flood basalt volcanism 隧道堤防的多脉冲和含晶就位：对洪水玄武岩火山作用的启示

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-04-01 Epub Date: 2026-02-03 DOI: 10.1016/j.epsl.2026.119895

Ryan M. Currier , Paulo J. Hidalgo , Tushar Mittal , Jada Nimblett , Lucian Bitner , Taiylor Williams , Bil Schneider

Flood basalt provinces, like the Columbia River Basalts (CRB), signify vast volcanic activity capable of inducing paleoclimatic shifts and extinction events via extensive volatile emissions. Two competing models exist for their rates of emplacement: one argues for slow, prolonged eruption based on lava flow morphology, while the other argues for rapid emplacement based on thermally constrained modeling of dikes, assuming crystal-poor, low-viscosity magmas fed through wide conduits. We test these assumptions by investigating the Tunnel Dike, a Chief Joseph Dike Swarm dike thought to be the feeder for several significant CRB flows. Thermal modeling indicates the dike was emplaced as relatively cool, crystal-laden magma, assembling incrementally to its final thickness. Crystal size distributions across the dike exhibit aphanitic margins which transition sharply into a porphyritic interior, where plagioclase commonly displays high-temperature deformation, with spatial distributions suggesting granular flow. These lines of evidence point to a multi-pulse, crystal-rich mush emplacement of the Tunnel Dike. Under these conditions, magmatic flux would have been orders of magnitude slower than previous estimates, aligning with flux rates based upon lava flow morphology of flood basalts and with peak effusion rates of the 1783 Laki fissure eruption. Although based on a single dike, the textures observed in the Tunnel Dike appear to be widespread across the CJDS, suggesting that crystal-rich, incremental dike emplacement may be more broadly characteristic of Columbia River Basalt magmatism. These findings carry implications for estimates of volatile emissions, and, consequently, paleoclimate modeling.

洪水玄武岩省，如哥伦比亚河玄武岩（CRB），表明巨大的火山活动能够通过大量挥发性排放物引起古气候变化和灭绝事件。关于喷发速度存在两种相互竞争的模型：一种是基于熔岩流形态的缓慢而持久的喷发，而另一种是基于热约束的岩脉模型的快速喷发，假设结晶性差、低粘度的岩浆通过宽管道注入。我们通过调查隧道堤防来检验这些假设，这条约瑟夫酋长堤防群堤防被认为是几个重要的CRB流的馈线。热模拟表明，岩脉的就位是相对较冷的、富含晶体的岩浆，逐渐聚集到最终的厚度。沿岩脉的晶体尺寸分布呈隐晶边缘，边缘向斑岩内部急剧过渡，其中斜长石通常表现为高温变形，空间分布呈粒状流动。这些证据表明隧道堤防有多脉冲，富含晶体的糊状掩体。在这些条件下，岩浆通量将比先前的估计慢几个数量级，与基于洪水玄武岩熔岩流形态的通量率和1783年拉基裂缝喷发的峰值流出率一致。虽然基于单一岩脉，但在隧道岩脉中观察到的结构似乎在CJDS中广泛存在，这表明富含晶体的渐进式岩脉侵位可能是哥伦比亚河玄武岩岩浆活动的更广泛特征。这些发现对挥发性排放物的估计以及古气候模型都有影响。

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引用次数: 0

Spatial variability and mechanics in aeolian ripples: A case study in Chilean Patagonia 风成波纹的空间变异性和力学：以智利巴塔哥尼亚为例

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-04-01 Epub Date: 2026-02-04 DOI: 10.1016/j.epsl.2026.119892

Tyler R. Gough , Chris H. Hugenholtz , Paul R. Nesbit , Thomas E. Barchyn

The transport capacity, sediment supply, and sediment availability in an aeolian landscape exert control on its bedforms. In this work, we use a 200 m long megaripple field forming on the 400 m high El Chingue escarpment in Chilean Patagonia as a case study in evaluating how spatial differences in these factors affect bedforms. Strong westerly winds encounter the steep escarpment of El Chingue, which creates a speed-up effect and increased transport capacity at the ridgeline followed by a trend of decreasing wind speed and transport capacity across the megaripple field. We describe and analyze the morphological, granulometric, and structural responses of the megaripples to this spatial trend. Results indicate that upwind megaripples are smaller, have poor sorting, thin armor layers, and no cross-bedding. In the middle of the field, the megaripples are larger, have thicker armor layers, a distinct bimodal distribution, and well-developed cross-bedding. At the downwind margin, megaripples are increasingly vegetated, generally flatter, and lose the distinct cross-bedding and bimodality. This transition of morphology, granulometry, and structure through the megaripple field reflects the spatial trend in transport capacity and aligns with current understanding of megaripple morphodynamic regimes. However, it highlights that different regimes may occur simultaneously within the same field. Broadly, these results emphasize the dynamic nature of megaripples and encourages the further application of a spatial analysis and sediment state understanding for ripple-scale bedforms to improve understanding of similar features across environments.

风成景观的输沙能力、泥沙供给和泥沙可利用性对其床型起着控制作用。在这项工作中，我们以智利巴塔哥尼亚400米高的El Chingue悬崖上200米长的巨型雷波场形成为例，评估这些因素的空间差异如何影响地层。强烈的西风遇到El chinue陡峭的陡坡，在山脊线上产生加速效应和运输能力增加，随后在整个巨ariple区风速和运输能力呈下降趋势。我们描述和分析了形态、粒度和结构对这一空间趋势的反应。结果表明，逆风巨型水波较小，分选差，护甲层薄，无交叉层理。在野地中部，巨核果较大，甲壳层较厚，双峰分布明显，交错层理发育良好。在下风边缘，巨果被越来越多的植被覆盖，通常是平坦的，失去了明显的交叉层理和双峰。这种形态、粒度和结构的转变通过巨果场反映了运输能力的空间趋势，并与目前对巨果形态动力学机制的理解一致。然而，它强调在同一领域内可能同时出现不同的制度。总的来说，这些结果强调了巨涟波的动态性质，并鼓励进一步应用空间分析和沉积物状态理解涟波尺度的河床，以提高对不同环境相似特征的理解。

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引用次数: 0

Why the end-Guadalupian biotic crisis differs from mass extinctions: Insights from high-precision geochronology and carbon cycle modeling 为什么瓜达卢普末期的生物危机不同于大灭绝：来自高精度地质年代学和碳循环模型的见解

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-04-01 Epub Date: 2026-02-07 DOI: 10.1016/j.epsl.2026.119898

Qiong Wu , Zhang-shuai Hou , Jahandar Ramezani , Dong-xun Yuan , Hua Zhang , Wen-qian Wang , Quan-feng Zheng , Yi-chun Zhang , Fei-fei Zhang , Guang-yi Wei , Shu-han Zhang , Yue Wang , Douglas H. Erwin , Yi-gang Xu , Shu-zhong Shen

Despite extensive release of carbon from eruptive pulses of Emeishan Large Igneous Province (ELIP) volcanism and increased temperatures, associated biotic crisis across the Guadalupian–Lopingian boundary (middle Permian) did not rise to the level of a mass extinction. Here we integrate new high-precision CA-ID-TIMS U-Pb zircon ages from South China, refining the Guadalupian–Lopingian boundary age to 259.857 ± 0.084 Ma (95 % C.I.) with carbon isotope and temperature records as the framework for carbon cycle modeling. We show that the magnitude and rate of carbon release during two warming phases associated with the ELIP eruptive pulses were substantially lower than those that drove Phanerozoic mass extinctions. Our findings provide a new explanation for why the end-Guadalupian biotic crisis did not escalate into a rapid mass extinction. This work suggests a threshold for the carbon injection rates required to generate climatic perturbations of sufficient magnitude and pace to trigger severe environmental stress and advances our understanding of the links between large igneous province volcanism, climate perturbations, and biotic resilience in Earth’s past.

尽管峨眉山大火成岩省（ELIP）火山活动的喷发脉冲释放了大量的碳，温度升高，但瓜达鲁普-洛平界线（中二叠纪）相关的生物危机并未上升到大灭绝的程度。本文结合华南地区新的高精度CA-ID-TIMS U-Pb锆石年龄，以碳同位素和温度记录为碳循环模型框架，将瓜达鲁普期-洛平期边界年龄修正为259.857±0.084 Ma （95% C.I.）。我们表明，在与ELIP爆发脉冲相关的两个变暖阶段，碳释放的幅度和速率大大低于驱动显生宙大灭绝的那些。我们的发现为瓜达卢普末期的生物危机为何没有升级为快速的大规模灭绝提供了新的解释。这项工作提出了产生足以引发严重环境压力的气候扰动所需的碳注入速率的阈值，并推进了我们对地球过去大型火成岩省火山活动、气候扰动和生物恢复力之间联系的理解。

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引用次数: 0

Reply to the comment of Rasmussen et al., on: Evolution of iron formation to ore during Ediacaran to early Paleozoic tectonic stability 回复Rasmussen等人关于埃迪卡拉纪到早古生代构造稳定性的铁形成到矿石的演化的评论

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-04-01 Epub Date: 2026-01-29 DOI: 10.1016/j.epsl.2026.119865

Anthony J. Fuentes , Liam Courtney-Davies , Rebecca Flowers , Yiming Zhang , Nicholas Swanson-Hysell

引用次数: 0

Accumulation of remineralised carbon and nutrients in the mid-depth Atlantic during Heinrich Stadial 1 and the Younger Dryas 海因里希第1期和新仙女木期大西洋中深度再矿化碳和营养物的积累

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-04-01 Epub Date: 2026-01-24 DOI: 10.1016/j.epsl.2026.119866

Joseph A. Stewart , Laura F. Robinson , James W.B. Rae , Naomi Pratt , Tianyu Chen , Maria Luiza de Carvalho Ferreira , Andrea Burke , Tao Li , Tina van de Flierdt

Atmospheric CO₂ and the temperature of the interior Atlantic Ocean both increased in 2-steps during the last deglaciation, particularly during Heinrich Stadial 1 (HS1; ∼16 ka) and the Younger Dryas (YD; ∼12 ka). However, what drove these punctuated rises remains a long-standing question. The role of deep-ocean carbon storage, release, and redistribution continues to be debated. To establish the role of ocean circulation in deglacial carbon and nutrient cycling, we present new multi-proxy data in sub-fossil corals from mid-depths in the Equatorial Atlantic, including boron isotopes (δ¹¹B; seawater pH), Ba/Ca (seawater [Ba] and refractory nutrients), and neodymium isotopes (ε_Nd; provenance of seawater signal). Corals are dated to a precise radiometric age scale and combined with previously published radiocarbon and temperature proxy measurements on the same samples. Our data reveal abrupt intervals (∼500 years) of notably low pH, Ba-rich, and radiocarbon-depleted (old) waters at 15.4 and 12.0 ka during HS1 and the YD at depths of ∼1700 m. However, very low ε_Nd (unradiogenic) values suggest that these corals were bathed in northern-sourced Atlantic waters throughout the deglaciation. These results imply that these (old) carbon- and nutrient-rich intermediate waters were not sourced from the carbon- and nutrient-rich Southern Ocean via Antarctic Intermediate Water (AAIW). Instead, carbon and nutrient accumulation at mid-depths in the tropical Atlantic was likely the result of remineralisation of organic matter at times of Atlantic Meridional Overturning Circulation (AMOC) slowdown. The Atlantic Ocean interior was therefore accumulating heat and carbon during these times when deepwater flushing was minimal, thus acting to partially dampen atmospheric CO₂ rise and warming caused by ventilation of the Southern and Pacific Oceans.

在末次冰期，大气CO2和大西洋内部温度均呈2级上升，特别是在Heinrich Stadial 1 （HS1; ~ 16 ka）和Younger Dryas （YD; ~ 12 ka）期间。然而，是什么推动了这些断断续续的上涨，仍然是一个长期存在的问题。深海碳储存、释放和再分配的作用仍在争论中。为了确定海洋环流在去冰碳和营养物循环中的作用，本文利用赤道大西洋中深海亚化石珊瑚的硼同位素（δ11B；海水pH）、Ba/Ca（海水[Ba]和难熔营养物）和钕同位素（εNd；海水信号来源）等新数据，研究了海洋环流在去冰碳和营养物循环中的作用。珊瑚的年代是精确的辐射年龄尺度，并结合先前发表的放射性碳和温度代理测量相同的样本。我们的数据揭示了HS1期间15.4 ka和12.0 ka的显著低pH、富ba和放射性碳枯竭（旧）水的突变间隔（~ 500年）和YD在深度~ 1700 m。然而，极低的εNd（非放射性成因）值表明，这些珊瑚在整个消冰期沐浴在北源的大西洋水域。这些结果表明，这些（古老的）富含碳和营养的中间水不是通过南极中间水（AAIW）来自富含碳和营养的南大洋。相反，热带大西洋中深度的碳和养分积累可能是大西洋经向翻转环流（AMOC）减缓时有机质再矿化的结果。因此，在深水冲刷最小的时期，大西洋内部积累了热量和碳，从而部分地抑制了大气中二氧化碳的上升和由南太平洋和太平洋的通风引起的变暖。

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引用次数: 0

Large-scale slab dynamics as drivers of seismicity: Modeling earthquakes in the izu-bonin-mariana subduction zones 大尺度板块动力学作为地震活动性的驱动因素：模拟伊豆-波宁-马里亚纳俯冲带的地震

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-04-01 Epub Date: 2026-01-29 DOI: 10.1016/j.epsl.2026.119878

Yida Li , Neil M. Ribe , Zhe Jia

Subduction zones host the majority of global earthquakes, ranging from shallow megathrust and outer-rise earthquakes to deep intraplate seismicity. Although it is well-established that subducting slabs supply the primary energy driving most earthquakes, the quantitative relationship between slab dynamics and seismic events remains poorly understood. Here we develop a comprehensive 3D geodynamic model of the Izu-Bonin-Mariana subduction system to quantitatively connect long-term slab dynamics with earthquake activity. Based on an analytical thermal model combined with slab geometry, we find that earthquakes predominantly occur under conditions cooler than  ∼ 900^∘C, defining a thermal boundary for the seismogenic zone. Within this zone, we identify a notable spatial correlation between the modeled energy dissipation rate and the observed distribution of seismicity, indicating that seismicity is intrinsically driven by long-term tectonic deformation. Furthermore, our comparison of the modeled stress state predictions with observed earthquake focal mechanisms reveals that both shallow megathrust and outer-rise earthquakes, as well as deep earthquakes associated with plate bending at the mantle transition zone, can be explained by slab dynamics. By analyzing the misfit between modeled and observed focal mechanisms, we further constrain slab rheology, finding that shallow earthquakes favor a relatively weak slab (yield stress of 100 – 150MPa), while deep earthquakes prefer a stronger slab (300 - 500MPa) accompanied by a 10 – 100–fold viscosity increase at the 660 km phase transition. Taken together, our results underscore the profound link between earthquake occurrence and the large-scale, long-term dynamics of mantle flow and subduction.

全球大部分地震都发生在俯冲带，范围从浅层大逆冲和外隆起地震到深层板内地震。虽然已经确定俯冲板块提供了驱动大多数地震的主要能量，但板块动力学与地震事件之间的定量关系仍然知之甚少。在这里，我们开发了一个全面的伊豆-博宁-马里亚纳俯冲系统的三维地球动力学模型，以定量地将长期的板块动力学与地震活动联系起来。根据结合板几何构造的解析热模型，我们发现地震主要发生在温度低于 ~ 900°C的条件下，从而为发震区定义了热边界。在该区域内，模拟能量耗散率与观测到的地震活动性分布具有显著的空间相关性，表明地震活动性本质上是由长期构造变形驱动的。此外，我们将模拟的应力状态预测与观测到的地震震源机制进行了比较，结果表明，无论是浅层大逆冲和外隆起地震，还是与地幔过渡带板块弯曲相关的深层地震，都可以用板块动力学来解释。通过分析模拟震源机制与观测震源机制之间的不拟合，我们进一步约束了板坯流变，发现浅层地震倾向于相对较弱的板坯（屈服应力为100 - 150MPa），而深层地震倾向于较强的板坯（300 - 500MPa），并在660 km相变处粘度增加10 - 100倍。综上所述，我们的研究结果强调了地震发生与大规模、长期的地幔流动和俯冲动力学之间的深刻联系。

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引用次数: 0

Reply to the comment on “The influence of cementation on fault stability” 回复“胶结对断层稳定性的影响”评论

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-04-01 Epub Date: 2026-01-21 DOI: 10.1016/j.epsl.2026.119867

G. Volpe , R. Affinito , L. Calzolari , G. Pozzi , C. Marone , C. Collettini

引用次数: 0

Zircon deformation features reveal sequence of transient high stress, tension and shearing during seismic faulting: A case study from the Ivrea-Verbano Zone, Italy 锆石变形特征揭示了地震断裂过程中瞬态高应力-张拉-剪切序列——以意大利Ivrea-Verbano带为例

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-04-01 Epub Date: 2026-01-22 DOI: 10.1016/j.epsl.2026.119858

Sandra Piazolo , Antonio Langone

The mechanisms associated with the propagation of fault ruptures remain debated in terms of sequence of events, processes and magnitude of stresses involved. Microstructures of zircon grains located within and in the immediate vicinity of pseudotachylyte veins reveal a sequence of events transient in time and space and allow recognition of different processes during rupture. The dynamic rupture causes, at its propagating tip, a damage zone of several centimetres thickness. In this damage zone, zircon grains exhibit crystal-plastic deformation signatures ranging from crystal lattice bending continuous throughout whole grains, to distinct planar deformation bands and {112} twin lamellae. Presence of planar deformation bands and {112} twin lamellae suggest locally high stresses, based on similar features reported from meteorite impacts. Absence of well-developed subgrains indicate dominance of low temperature plasticity at the rupture tip. Subsequently, those grains with highest dislocation densities undergo in-situ grain fragmentation. The observed correlation of grains with very high dislocation densities and in-situ grain fragmentation suggests that the effective tensile strength of these grains is sufficiently decreased by the high stored elastic energy to cause their fragmentation when subject to tensile stresses in the wake of the propagating rupture tip. Subsequent displacement along connected damage zone fracture surfaces results in pseudotachylytes formation.

Our data shows that dynamic rupture initiation and propagation results in stresses heterogeneously distributed in space, magnitude and sign causing both ductile and brittle deformation. Our study highlights the value of the accessory mineral zircon in deciphering the nature of rupture zone dynamics.

与断层破裂传播相关的机制在事件顺序、过程和所涉及的应力大小方面仍然存在争议。锆石颗粒的微观结构显示了一系列在时间和空间上短暂的事件，并允许识别破裂过程中的不同过程。动态破裂在其传播尖端造成数厘米厚的损伤区。在该损伤带中，锆石颗粒表现出晶体塑性变形特征，从整个颗粒的晶格连续弯曲到明显的平面变形带和{112}孪晶片。平面变形带和{112}孪晶片的存在表明，根据陨石撞击报道的类似特征，局部存在高应力。缺乏发育良好的亚晶表明在断裂尖端以低温塑性为主。随后，位错密度最高的晶粒发生原位破碎。观察到的具有极高位错密度的晶粒与原位晶粒破碎的相关性表明，当在扩展的破裂尖端受到拉伸应力时，这些晶粒的有效抗拉强度因储存的高弹性能而充分降低，从而导致其破碎。随后沿着连接的损伤区裂缝表面进行位移，形成假羟基地层。我们的数据表明，动态破裂的开始和扩展导致应力在空间、大小和符号上的非均匀分布，导致韧性和脆性变形。我们的研究强调了伴生矿物锆石在解释破裂带动力学性质方面的价值。

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引用次数: 0

Induced seismicity in the southern Sichuan basin regulated by heterogeneous folding 四川盆地南部受非均质褶皱控制的诱发地震活动

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-04-01 Epub Date: 2026-01-23 DOI: 10.1016/j.epsl.2026.119860

Bingfeng Zhang , Xuewei Bao , Mengfan Jiang , Kecheng Zhou

The potential for strong induced earthquakes in industrial production fields is largely controlled by the spatial arrangement of pre-existing faults shaped by regional tectonics. The 2021 Ms 6.0 Luxian earthquake in the southern Sichuan basin is an unusual case in which the seismogenic fault geometry deviates from the prevailing regional stress field and geological framework. To date, the seismogenic environment and the tectonic processes responsible for this destructive event remain poorly understood. In this study, we present a sedimentary shear-wave velocity model and eleven moment tensor solutions across the Luxian shale gas field, derived using data collected by our newly deployed seismic network. Our results reveal previously unrecognized, nearly reversed lateral variations in the amplitudes of synclinal low-velocity anomalies between terrestrial and marine strata, in addition to a first-order velocity contrast that correlates with the regional anticline–syncline architecture. The central Yujiasi syncline exhibits weaker low-velocity anomalies in the shallow terrestrial strata than areas to the north and south, reflecting lower strain intensity likely influenced by shallower décollement layers. Detected seismicity and anomalous reverse-faulting events with fold-parallel P-axes (including the Ms 6.0 earthquake) cluster mainly within two strain transition zones of the Yujiasi syncline, where stress is expected to concentrate and form fold-normal fault planes. These observations provide direct evidence that heterogeneous folding regulates the spatial distribution of induced seismicity in the southern Sichuan basin. They also help identify areas susceptible to induced seismic hazards and provide guidance for planning hydraulic fracturing operations in the region.

工业生产领域发生强震的可能性在很大程度上受区域构造形成的既存断层的空间排列控制。2021年四川盆地南部陆县6.0级地震是一个不寻常的例子，其中发震断层的几何形状偏离了主要的区域应力场和地质框架。迄今为止，人们对这次破坏性事件的发震环境和构造过程仍然知之甚少。在这项研究中，我们利用新部署的地震台网收集的数据，建立了一个横跨芦县页岩气田的沉积横波速度模型和11个矩张量解。我们的研究结果揭示了以前未被认识到的，在陆相和海相地层之间的向斜低速异常振幅中几乎反向的横向变化，以及与区域背斜-向斜结构相关的一级速度对比。渝家泗向斜中部浅层陆相低速异常弱于南北地区，反映出可能受浅层结层影响的应变强度较低。以褶皱平行p轴（包括6.0级地震）探测到的地震活动性和异常逆断层事件主要集中在余家寺向斜的两个应变过渡带内，预计应力将集中形成褶皱正断层面。这些观测结果为非均质褶皱调节川南地区诱发地震活动的空间分布提供了直接证据。它们还有助于识别易受诱发地震危害的区域，并为该地区的水力压裂作业规划提供指导。

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引用次数: 0