Earth and Planetary Science Letters最新文献_第10页

Role of hydrothermal alteration and thermally activated healing on earthquake dynamics along oceanic transform faults 热液蚀变和热活化愈合在海洋转换断层地震动力学中的作用

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-02-01 Epub Date: 2025-12-06 DOI: 10.1016/j.epsl.2025.119765

Mingqi Liu, Sylvain Barbot

The generation of earthquakes is primarily governed by the thermo-mechanical and structural properties of fault zones. However, the influence of lithological and hydrothermal factors on the rupture style, size, and recurrence patterns of seismic activity remains poorly understood. Here, we explore the role of hydrothermal alteration on the spatial distribution and source characteristics of earthquakes along oceanic transform faults. We perform three-dimensional seismic cycle simulations calibrated with thermal profiles from thermo-mechanical geodynamic models and laboratory-derived frictional properties of crust and mantle rocks to elucidate the seismic patterns of oceanic transform faults. The thermally activated healing of antigorite in serpentinized mantle pockets may facilitate the spontaneous generation of seismic swarms, depending on the intensity of shear heating and the activation energy of the healing process. Fluid circulation influences seismic behavior by driving local alteration, affecting fault frictional properties. The unstable nature of gabbro friction over a finite range of temperature supports a narrow seismogenic zone within the oceanic crust, with a lateral extent of seismic ruptures limited by patches of hydrothermal alteration products (e.g., talc and chlorite) within the fault zone. Abundant microseismicity may occur within partially altered, heterogeneous barrier zones. These findings highlight the critical interplay between lithology, hydrothermal processes, and fault mechanics, providing new insights into the tectonic framework of seismicity along oceanic transform faults.

地震的发生主要受断裂带的热力学和构造性质的支配。然而，岩性和热液因素对地震活动的破裂方式、大小和复发模式的影响仍然知之甚少。本文探讨了热液蚀变对海洋转换断层地震空间分布和震源特征的影响。利用热力学地球动力学模型和实验室导出的地壳和地幔岩石摩擦特性的热剖面进行三维地震周期模拟，以阐明海洋转换断层的地震模式。蛇纹岩化地幔穴中反长花岗岩的热活化愈合可能促进地震群的自发产生，这取决于剪切加热的强度和愈合过程的活化能。流体循环通过驱动局部蚀变来影响地震行为，从而影响断层的摩擦特性。辉长岩摩擦在有限温度范围内的不稳定性支持了海洋地壳内狭窄的发震带，地震破裂的横向程度受断裂带内热液蚀变产物（如滑石和绿泥石）的限制。丰富的微震活动可能发生在部分蚀变的非均质屏障带内。这些发现突出了岩性、热液过程和断层力学之间的关键相互作用，为海洋转换断层地震活动的构造格局提供了新的见解。

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引用次数: 0

Enhanced marine primary productivity during the long-term Ordovician cooling: A barium isotope perspective from South China 奥陶系长期降温过程中海洋初级生产力的增强：来自华南的钡同位素视角

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-02-01 Epub Date: 2025-12-15 DOI: 10.1016/j.epsl.2025.119783

Shengchao Yang , Junxuan Fan , Chao Li , Yi-Bo Lin , Yiying Deng , Zongyuan Sun , Jian Cao , Shu-zhong Shen

Global cooling has been strongly associated with the Great Ordovician Biodiversification Event (GOBE), but the underlying mechanisms remain unexplored. To assess whether enhanced biological pump contributed to global cooling during the GOBE, we performed δ¹³⁸Ba_carb-δ¹³C_carb analyses on an Ordovician shallow marine limestone section from South China. Our results show that δ¹³⁸Ba_carb in the Ordovician (median 0.73‰) is significantly higher than in other geological periods and reservoirs (median values ranging from –0.18‰ to 0.29‰), indicating exceptionally high δ¹³⁸Ba values in the surface ocean in South China, possibly due to plankton radiation, which increased the removal of Ba during the GOBE. Furthermore, shifts in δ¹³⁸Ba_carb correlated with long-term increases in δ¹³C_carb, with positive correlation during the early Tremadocian (Stage 1), followed by negative correlation during the late Tremadocian to Dapingian (Stage 2), and positive correlation from the Darriwilian to Katian (Stage 3). These δ¹³⁸Ba_carb-δ¹³C_carb covariations suggest that marine primary productivity was enhanced during the Ordovician in South China. Additionally, the gradual increase in δ¹³C_carb is strongly correlated with global cooling and an increase in marine biodiversity, suggesting that plankton radiation during the GOBE may be an important cause of the increased marine primary productivity, thus enhancing organic carbon burial, contributing to the long-term Ordovician cooling, and linking the GOBE and contemporaneous environmental changes.

全球变冷与奥陶纪生物大多样化事件（GOBE）密切相关，但其潜在机制尚未探索。为了评估增强的生物泵是否对GOBE期间的全球降温做出了贡献，我们对中国南方奥陶系浅海灰岩剖面进行了δ 13bacarb -δ13Ccarb分析。结果表明，奥陶纪δ138Bacarb值（中值0.73‰）显著高于其他地质时期和储层（中值范围为-0.18‰~ 0.29‰），表明华南表层海洋δ138Ba值异常高，可能是浮游生物辐射导致的，在GOBE时期增加了Ba的去除。δ13Ccarb的变化与δ13Ccarb的长期升高相关，在Tremadocian早期（第1阶段）呈正相关，在Tremadocian晚期至大坪期（第2阶段）呈负相关，在Darriwilian至Katian阶段呈正相关（第3阶段）。这些δ138Bacarb-δ13Ccarb共变表明中国南方奥陶纪海相初级生产力增强。δ13Ccarb的逐渐增加与全球变冷和海洋生物多样性的增加密切相关，表明GOBE时期的浮游生物辐射可能是海洋初级生产力增加的重要原因，从而增强了有机碳埋藏，促进了奥陶纪的长期降温，并将GOBE与同期环境变化联系起来。

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引用次数: 0

Fixation of atmospheric nitrogen on present-day Mars during dust events 沙尘事件期间火星大气氮的固定

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-02-01 Epub Date: 2025-12-17 DOI: 10.1016/j.epsl.2025.119786

Wenshuo Mao , Xiaohui Fu , Zhongchen Wu , Jiang Zhang , Zongcheng Ling , Yang Liu , Yu-Yan Sara Zhao , Jiacheng Liu , He Cui , Hitesh G. Changela , Yuheng Ni , Lifang Li , Joseph R. Michalski

N₂ is the second most abundant gas in the present-day Martian atmosphere and hosts the essential biochemical element N. Nitrate and (per)chlorate have been detected in numerous aeolian sediments in Gale crater. Thus, a potential nitrogen fixation may be active on present-day Mars. Interactions between Martian atmosphere and surface during dust events can trigger electrostatic discharge (ESD) and complex electrochemical reactions. By simulating this process in a Mars chamber, nitrate and (per)chlorate were produced under present-day Martian atmospheric conditions. Notably, the obtained nitrate/(per)chlorate abundance ratio is in agreement with Gale crater observations (< 1.0), but much lower than those in terrestrial Mars analogues and the products of other pathways proposed for Mars. The results strongly indicate that electrochemical reactions during Mars dust events represents a new nitrogen fixation mechanism on present-day Mars. It is different from other fixation processes on Earth and early Mars, expanding the knowledge of nitrogen cycle and nitrogen fixation in solar system. Electrochemical reactions may also play crucial roles in global nitrogen cycling throughout the Amazonian period. These nitrate salts in Martian dusts potentially provide an accessible source of nitrogen for possible organic molecule formation on present-day Mars.

氮气是现今火星大气中含量第二丰富的气体，含有必要的生物化学元素n。在盖尔陨石坑的大量风成沉积物中发现了硝酸盐和氯酸盐。因此，在今天的火星上可能存在潜在的固氮作用。尘埃事件发生时火星大气与地表的相互作用会引发静电放电和复杂的电化学反应。通过在火星室内模拟这一过程，硝酸盐和氯酸盐（per）在今天的火星大气条件下产生。值得注意的是，获得的硝酸盐/氯酸盐丰度比与Gale陨石坑观测值一致（< 1.0），但远低于陆地火星类似物和其他途径提出的火星产物。结果有力地表明，火星尘埃事件中的电化学反应代表了一种新的火星固氮机制。它不同于地球和早期火星上的其他固定过程，扩展了对太阳系氮循环和氮固定的认识。电化学反应也可能在整个亚马逊时期的全球氮循环中发挥关键作用。火星尘埃中的这些硝酸盐可能为今天火星上可能形成的有机分子提供了一种可行的氮源。

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引用次数: 0

Using rate-and-state friction constitutive laws to predict seismicity rates for ice rifts on the Ross Ice Shelf in Antarctica 利用速率和状态摩擦本构定律预测南极洲罗斯冰架冰裂缝的地震活动率

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-02-01 Epub Date: 2025-12-17 DOI: 10.1016/j.epsl.2025.119790

Kathrine Udell-Lopez, Mong-Han Huang, Vedran Lekić

Determining what fault characteristics and applied stress conditions modulate the occurrence of seismicity is a key question in the field of seismology. Here we analyze the seismicity measured at two ice shelf rift zones of different maturity in the Ross Ice Shelf, which are subjected to long-term dilatational stress modulated by tidal stress variations. We analyze the periodicity of the seismicity and its relationship to tidal stress variations and find that the seismicity rate at both rifts is controlled by tidal stress rate variations. We compare the observed icequake occurrence times with analytical predictions from rate-and-state friction constitutive laws that have been used to model frictional behavior on terrestrial faults. We find that seismicity rate is predicted well by an analytical model based on rate-and-state friction, confirming that it can be used to understand ice rift seismicity. We constrain for the first time the characteristic time of seismicity rate,

t_{a}

, for both rifts, and find that ice rifts have a faster recovery time than continental faults, and that their responses to stress and characteristic times are age dependent. This implies that the strength of the rift changes with time and determines the amount of stress or stress rate dependency of the system. Our results can be used to understand seismicity occurrence across other ice rifts in Antarctica and Greenland and holds implications for seismicity on icy satellites.

确定什么样的断层特征和外加应力条件调节地震活动性的发生是地震学领域的一个关键问题。本文分析了罗斯冰架两个不同成熟度冰架裂谷带的地震活动性，这些裂谷带受到潮汐应力变化调制的长期膨胀应力的影响。分析了地震活动性的周期性及其与潮汐应力变化的关系，发现两个裂谷的地震活动性受潮汐应力变化的控制。我们将观测到的地震发生时间与基于速率和状态摩擦本构定律的分析预测进行了比较，这些本构定律已被用于模拟陆地断层的摩擦行为。我们发现基于速率-状态摩擦的解析模型可以很好地预测地震活动性，证实了它可以用来理解冰裂谷地震活动性。我们首次约束了两个裂谷的地震活动性特征时间，发现冰裂谷比大陆断层有更快的恢复时间，并且它们对应力和特征时间的响应依赖于年龄。这意味着裂缝的强度随时间而变化，并决定了系统的应力量或应力速率依赖性。我们的结果可以用来了解南极洲和格陵兰岛其他冰裂谷的地震活动，并对冰冻卫星的地震活动产生影响。

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引用次数: 0

Apatite records mechanical and chemical processes over the lifetime of a subduction interface, Andros Island, Greece 在希腊安德罗斯岛，磷灰石记录了俯冲界面的机械和化学过程

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-02-01 Epub Date: 2025-12-11 DOI: 10.1016/j.epsl.2025.119779

Eirini M. Poulaki , Cailey B. Condit , Margaret L. Odlum , Jason N. Ott , Megan E. Ferrell

The subduction plate interface accommodates deformation between the downgoing and overriding plates and features a range of mechanical and chemical processes that influence the strength and slip behavior of this zone. Apatite, a calcium phosphate accessory mineral, records these subduction processes including metamorphism, metasomatism, and deformation. It can deform, recrystallize, and archive chemical processes through its trace elements across the pressure and temperatures conditions that span the depths at the bottom of the subduction seismogenic zone. We leverage these apatite characteristics in a metabasite within an exhumed subduction complex on Andros Island, Greece to demonstrate that apatite grains show multiple deformation mechanisms and inform on fluid’s composition and role in deformation processes. Apatite deformation mechanisms are dependent on the surrounding mineral phases, with grains within the chlorite matrix exhibiting evidence of dissolution-precipitation while grains in contact with strong mineral phases (e.g., clinozoisite, albite) deform by dislocation-accommodated deformation. Dislocations formed by prism 〈c〉 slip in apatite act as pathways for fluid mobile elements during deformation while dislocations formed by basal 〈a〉 slip did not facilitate trace element diffusivity, likely due to a crystallographic control. We also show that apatite is a powerful geochemical archive recording infiltration of aqueous sedimentary fluids with small amounts of CO₂ during metasomatism. We highlight the utility of in-situ apatite geochemistry in polymetamorphic and polydeformed rocks. We show that even at the grain scale, lattice impurities will control the geochemical signatures.

俯冲板块界面容纳了下行板块和上覆板块之间的变形，并具有一系列影响该带强度和滑移行为的机械和化学过程。磷灰石是一种磷酸钙辅助矿物，记录了这些俯冲过程，包括变质作用、交代作用和变形作用。它可以变形、再结晶，并通过其微量元素在压力和温度条件下记录化学过程，这些条件跨越了俯冲发震带底部的深度。我们利用这些磷灰石特征在希腊安德罗斯岛的一个潜没杂岩中发现的变质岩中，证明磷灰石颗粒具有多种变形机制，并为流体成分和变形过程中的作用提供了信息。磷灰石的变形机制取决于周围的矿物相，绿泥石基质中的颗粒表现出溶解沉淀的证据，而与强矿物相（如斜沸石、钠长石）接触的颗粒则通过位错调节变形而变形。磷灰石中棱柱状< c >滑移形成的位错是变形过程中流体流动元素的通道，而基底< a >滑移形成的位错可能受晶体学控制，不能促进微量元素的扩散。我们还表明，磷灰石是一个强大的地球化学档案，记录了在交代过程中含有少量CO2的含水沉积流体的渗透。我们强调了原位磷灰石地球化学在多变质和多变形岩石中的应用。我们发现，即使在晶粒尺度上，晶格杂质也会控制地球化学特征。

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引用次数: 0

The lithosphere - asthenosphere system seen by surface waves: New insights from radial anisotropy 表面波所见的岩石圈-软流圈系统：来自径向各向异性的新见解

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-01-01 Epub Date: 2025-11-17 DOI: 10.1016/j.epsl.2025.119720

S. Durand, E. Debayle, Y. Ricard

We propose a conceptual model of the lithosphere-asthenosphere system that reconciles a number of surface wave observations. It comes in the context of the development of a new SV wave velocity,

V_{s v}

, and radial anisotropy, ξ, global model based on multi-mode Rayleigh and Love wave data. The Rayleigh dataset has also been used in previous studies to constrain the azimuthal anisotropy, the quality factor Q and the melt content. All these models are based on self-consistent datasets and use the same waveform modeling and tomographic approaches, with similar regularization and smoothing. The first important finding of this study is the fact that a 1-D ξ model close to PREM but including a 3D crust structure explains our dataset almost everywhere, except in oldest parts of the continents (mainly Archean and Proterozoic terrains) and youngest parts of the Pacific ridge (mainly ages ≤ 50 Ma) where 3-D variations of ξ are required. Based on this, we build an hybrid model, Hybrid 1D/3D, where ξ is fixed to a 1-D profile when sufficient to fit the data, and inverted for when the dataset requires lateral variations. Our radially anisotropic model shows that there is no age dependance of the radial anisotropy ξ in the oceanic lithosphere while age is the main parameter controlling

V_{s v}

, melt content and azimuthal anisotropy, particularly under fast plates. We also find that positive radial anisotropy (

ξ > 1

) extends deeper beneath oceans (down to 350 km depth) than beneath continents. We propose that the thicker radially anisotropic layer under the oceans compared to the continent indicates a change in origin from frozen-only anisotropy under the continent to a more complex situation under the oceans. Cratons appear fast, melt-free and anisotropic, down to 200-250 km depth, and anomalies with ξ≤ 1 are present in the deeper part of the cratonic roots (around 250 km) that could reflect past delamination or compression of the deep lithospheric roots.

我们提出了一个岩石圈-软流圈系统的概念模型，该模型与许多表面波观测相协调。它是在基于多模Rayleigh和Love波数据的新的SV波速（Vsv）和径向各向异性（ξ）全球模型的发展背景下出现的。在以往的研究中，Rayleigh数据集也被用来约束方位角各向异性、质量因子Q和熔体含量。所有这些模型都基于自一致的数据集，并使用相同的波形建模和层析方法，具有相似的正则化和平滑。本研究的第一个重要发现是，一个接近PREM的一维ξ模型，但包括三维地壳结构，几乎可以解释我们的数据集无处不在，除了大陆最古老的部分（主要是太古宙和元古宙地形）和太平洋脊最年轻的部分（主要年龄≤50 Ma），那里需要ξ的三维变化。在此基础上，我们建立了一个混合模型，hybrid 1D/3D，当数据足以拟合时，ξ固定为1-D轮廓，当数据集需要横向变化时，ξ被反转。我们的径向各向异性模型表明，海洋岩石圈的径向各向异性ξ与年龄无关，年龄是控制Vsv、熔体含量和方位各向异性的主要参数，特别是在快速板块下。我们还发现，正径向各向异性（ξ>1）在海洋下延伸的深度（深达350公里）比在大陆下延伸的深度更深。我们认为，与大陆相比，海洋下径向各向异性层较厚，表明起源从大陆下的冻结各向异性转变为海洋下更复杂的情况。克拉通在200 ~ 250 km深度下表现为快速、无熔体和各向异性，在克拉通根部较深处（250 km左右）存在ξ≤1的异常，这可能反映了岩石圈深层根部过去的分层或压缩。

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引用次数: 0

Final differentiation of the lunar magma ocean: genesis of KREEP and the limited role of silicate liquid immiscibility 月球岩浆海的最终分异：KREEP的成因和硅酸盐液体不混溶的有限作用

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-01-01 Epub Date: 2025-11-13 DOI: 10.1016/j.epsl.2025.119691

Weronika Ofierska, Max W. Schmidt, Christian Liebske, Paolo A. Sossi

Owing to the incompatibility of K, rare-earth elements (REE) and P in silicate minerals relative to melt, the KREEP component, found on the near-side of the Moon, is thought to have formed through protracted crystallisation of the Lunar Magma Ocean (LMO). Our fractional crystallisation experiments simulate the final stages of LMO crystallisation, from plagioclase onset to the last eutectic melt remnants. Results show the LMO liquid to remain saturated in olivine ± orthopyroxene ± Cr-spinel up to 74 % solidification (PCS), transitioning to plagioclase+clinopyroxene (cpx) from 1200 °C (74 PCS) to 1120 °C (88 PCS). The plagioclase+cpx+quartz cotectic is reached at 1080 °C (92.3 PCS), with liquid immiscibility and a crystal assemblage of plagioclase+augite+Ti-spinel+ilmenite+quartz occurring at 1030 °C (98.8 PCS), until nearly complete crystallization is reached at 1000 °C (99.5 PCS). Mineral/melt (plagioclase, pigeonite, high-Ca cpx) and melt/melt partition coefficients for K, REE, P, Zr, Hf, Nb, Th, and U were determined. They are used to model melt evolution to 99.5 PCS, showing that fractional crystallisation alone replicates KREEP’s REE profile and the above trace elements, yet, distinct Lu/Hf (and U/Pb) ratios suggest additional processes. Assuming a finite oxygen budget in the LMO and incompatible behaviour of Fe³⁺, the Eu anomaly of KREEP is best reproduced by a model in which oxygen fugacity (

f_{o_{2}}

) evolves from one log unit below to 1.5 log units above the iron-wustite buffer (IW-1 to IW+1.5) from 0 PCS to 99.4 PCS. Minor dacitic melt separation (1–5 % of the melt remaining at 1030 °C) sequestering K from REE+P is consistent with but unnecessary for KREEP formation; nevertheless, a second-stage partial re-melting of these dacites could match observed FeO and incompatible element abundances of lunar granites.

由于硅酸盐矿物中K、稀土元素（REE）和P与熔体不相容，在月球近侧发现的KREEP成分被认为是通过月球岩浆海洋（LMO）的长期结晶形成的。我们的分数结晶实验模拟了LMO结晶的最后阶段，从斜长石开始到最后的共晶熔体残余。结果表明，LMO液体在橄榄石±正辉石±cr尖晶石中保持饱和状态，凝固量高达74% (PCS)，从1200℃（74 PCS）到1120℃（88 PCS）过渡为斜长石+斜辉石（cpx）。在1080℃（92.3 PCS）时形成斜长石+cpx+石英共晶，在1030℃（98.8 PCS）时形成斜长石+辉石+钛尖晶石+钛铁矿+石英的不混相晶体组合，在1000℃（99.5 PCS）时接近完全结晶。测定了矿物/熔体（斜长石、鸽石、高钙cpx）和K、REE、P、Zr、Hf、Nb、Th、U的熔体/熔体分配系数。它们被用来模拟熔体演化至99.5 PCS，表明单是分数结晶就复制了KREEP的REE剖面和上述微量元素，然而，不同的Lu/Hf（和U/Pb）比率表明有其他过程。假设LMO中氧收支有限且Fe3+不相容，KREEP的Eu异常可以通过氧逸度（fo2）从低于铁-浮氏体缓冲层（IW-1至IW+1.5）的1个对数单位到高于铁-浮氏体缓冲层（IW-1至IW+1.5）的1.5个对数单位从0 PCS到99.4 PCS的模型得到最好的再现。少量的酸性熔体分离（熔体在1030°C时仍有1 - 5%的熔体残留）对REE+P中K的分离与KREEP形成一致，但不是必需的；然而，这些英安岩的第二阶段部分再熔融可以与观测到的月球花岗岩的FeO和不相容元素丰度相匹配。

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引用次数: 0

Contrasting topography of continental large igneous provinces: Crucial role of crustal flow and intrusion dynamics 大陆大火成岩省的对比地形：地壳流动和侵入动力学的关键作用

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-01-01 Epub Date: 2025-11-14 DOI: 10.1016/j.epsl.2025.119726

Xiaochuan Tian , W. Roger Buck

The Ethiopian and Columbia Plateaus, surface expressions of the two youngest continental Large Igneous Provinces (LIPs), exhibit contrasting topographies: the Ethiopian Plateau rises ∼1.5 km above its surroundings, while the Columbia Plateau sits ∼0.7 km below. Using semi-analytic and numerical models, we show that these differences may arise from the interplay between intrusion dynamics and geotherm dependent lower crustal flow—without requiring mantle plume buoyancy (uplift) or deep crust eclogitization (subsidence). The semi-analytic models show that slow lower crustal flow leads to long-lived uplift regardless of intrusion style. Subsidence, in contrast, requires both moderately fast flow and mechanically coupled mafic intrusions in the brittle upper crust. More realistic numerical simulations incorporating evolving geotherms and sill intrusion depths reveal that cold crust promotes uplift through thickening, consistent with Ethiopia, while hot crust allows mechanically coupled denser intrusions to drive lateral flow and surface subsidence, as seen in Columbia. Together with intrusion induced crustal densification for triggering main-phase eruption, the models may explain the synchronized subsidence and flood basalt eruptions inferred from Columbia. Through scaling, a characteristic time for lower crustal flow emerges to quantitatively predict continental LIP topographic developments among all models. These results highlight the lower crust as a dynamic buffer zone that governs surface response to magmatic emplacements, overriding effects of deeper crustal or mantle loads.

埃塞俄比亚高原和哥伦比亚高原是两个最年轻的大陆大火成岩省（LIPs）的地表表达，它们表现出截然不同的地形：埃塞俄比亚高原高出周围环境约1.5公里，而哥伦比亚高原则低于周围环境约0.7公里。利用半解析模型和数值模型，我们表明这些差异可能是由侵入动力学和依赖地热的下地壳流动之间的相互作用引起的，而不需要地幔柱浮力（隆起）或深部地壳榴辉化（下沉）。半解析模型表明，无论何种侵入方式，缓慢的下地壳流动都会导致长时间的隆升。相比之下，下沉既需要适度的快速流动，也需要脆性上地壳中机械耦合的基性侵入。结合不断变化的地热和侵入深度的更现实的数值模拟显示，与埃塞俄比亚的情况一致，冷地壳通过增厚促进隆升，而热地壳允许机械耦合的密集侵入驱动侧向流动和地表下沉，如哥伦比亚所见。结合侵入引起的地壳致密化引发的主相喷发，该模型可以解释哥伦比亚盆地的同步沉降和洪水玄武岩喷发。通过尺度变换，形成了下地壳流动的特征时间，可定量预测各模式中陆面地形的发展。这些结果突出表明，下地壳是一个动态缓冲带，控制着岩浆侵位的地表响应，以及深部地壳或地幔负载的压倒效应。

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引用次数: 0

Density and viscosity variations due to plume melting of a bilithologic mantle: Implications for asthenosphere and hotspot swell root dynamics 生物地幔羽流熔融引起的密度和粘度变化：对软流圈和热点膨胀根动力学的影响

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-01-01 Epub Date: 2025-11-14 DOI: 10.1016/j.epsl.2025.119724

Jia Shao , Jason P. Morgan

Geochemical and petrological observations indicate that mantle plumes consist mainly of peridotite with ∼10–30% embedded pyroxenite veins or blobs. However, the consequences of preferential deeper pyroxenite-rich melting followed by shallower peridotite-rich melting on mantle density and viscosity have yet to be systematically explored. Using 1-D numerical simulations, we investigate density and viscosity changes during upwelling and pressure-release melting of a damp bilithologic mantle aggregate. We find that denser pyroxenite begins melting deeper than its surrounding peridotite. Preferential early pyroxenite melting significantly reduces mantle density by decreasing the volume fraction of this denser component, but only slightly increases mantle viscosity (<3-fold) as the weaker damp peridotite matrix dominates the overall rheology. When peridotite melts and dries at shallower depths, its compositional depletion continues reducing density but to a lesser extent than prior pyroxenite removal, while its dehydration significantly increases the mantle’s viscosity (1–2 orders of magnitude). When dry peridotite melting begins, its higher productivity and latent heat extraction also typically suppresses additional pyroxenite melting. After deep pyroxenite melting, residues of relatively colder material near plume rims have fluid (damp peridotite) viscosity and compositionally buoyant (pyroxenite-poor) density. This tends to form a low-viscosity, compositionally buoyant layer beneath oceanic lithosphere that could be preferentially sampled by subsequent mid-ocean ridge upwelling and melting. In contrast, the hottest plume fractions undergo both pyroxenite and peridotite melting during upwelling beneath oceanic lithosphere. This extensive melting generates a high-viscosity, buoyant restite fraction that adheres to and moves with overlying lithosphere as a hotspot swell root.

地球化学和岩石学观测表明，地幔柱主要由橄榄岩组成，其中约10-30%的辉石脉或斑岩嵌套。然而，深部富辉石岩优先熔融后浅层富橄榄岩熔融对地幔密度和粘度的影响尚未得到系统探讨。利用一维数值模拟方法，研究了潮湿生物地幔聚集体在上升流和压力释放熔融过程中密度和粘度的变化。我们发现密度更大的辉石岩比它周围的橄榄岩融化得更深。早期辉石岩优先熔融通过降低较致密组分的体积分数显著降低了地幔密度，但由于较弱的潮湿橄榄岩基质主导了整体流变学，因此只略微增加了地幔粘度（3倍）。当橄榄岩在较浅深度熔融干燥时，其成分损耗继续降低密度，但程度低于先前的辉石岩去除，而其脱水显著增加了地幔的粘度（1-2个数量级）。当干橄榄岩开始熔化时，其较高的生产率和潜热提取通常也抑制了额外的辉石岩熔化。在深部辉石岩熔融后，羽流边缘附近相对较冷的物质残留物具有流体（湿橄榄岩）粘度和成分浮力（辉石岩）密度。这倾向于在海洋岩石圈下形成一个低粘度、成分浮力的层，随后的洋中脊上升流和融化可能优先对其进行取样。相反，在海洋岩石圈下的上升流过程中，最热的羽流组分经历了辉石岩和橄榄岩的融化。这种广泛的融化产生了高粘度、浮力的阻力部分，它作为热点膨胀根附着在上覆岩石圈上并随岩石圈移动。

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引用次数: 0

Significant crustal uplift attributed to contemporary glacier loss over laterally heterogeneous mantle 显著的地壳隆起归因于横向非均质地幔上的当代冰川损失

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2026-01-01 Epub Date: 2025-11-14 DOI: 10.1016/j.epsl.2025.119725

Zhengyang Wang , Wei Feng , Zhongshan Jiang , Zhou Wu , Baoming Tian , Haipeng Luo , Min Zhong , Hao Wei

Contemporary ice mass loss from the Northern and Southern Patagonian icefields, overlying a slab window from Chile Ridge subduction, drives exceptional crustal uplift through combined glacio-isostatic and tectonic responses. To capture the spatially detailed deformation field, we employed sparse GNSS stations to accomplish the mosaicking and calibration of InSAR-derived velocity fields through block adjustment. The calibrated deformation field exhibits pronounced spatial heterogeneity, with uplift rates increasing southward to a maximum of 40 mm/yr over the northern sector of the Southern Icefield, before decreasing to 0–10 mm/yr toward its southern margin. In the east-west direction, velocities average 12 mm/yr in the western sector, contrasting sharply with rates of 25 mm/yr in the east, spatially coinciding with the slab window boundary. By modeling transient elastic deformation from contemporary ice melt, we find that the elastic component accounts for only 23 % of the observed InSAR signal. We further conducted viscoelastic deformation modeling under varying mantle viscosities and fitted the results to the calibrated velocity field to identify optimal viscosity settings in different regions. The fitting results confirm viscosity contrast in both the north-south and east-west directions, characterized by four subdomains exhibiting upper mantle viscosity variations from 3 × 10¹⁸ to 1.7 × 10¹⁹ Pa s. The viscosity heterogeneity provides critical constraints for further refining three-dimensional (3-D) rheological structures. Our findings promote the development of more accurate regional GIA models and contribute to a better understanding of the underlying geodynamic process.

来自巴塔哥尼亚北部和南部冰原的当代冰块损失，覆盖在智利山脊俯冲的板块窗口上，通过冰川-均衡和构造反应的结合，驱动了异常的地壳隆起。为了获取空间细节化的形变场，我们利用稀疏GNSS站点，通过块差调整完成insar导出的速度场的拼接和定标。校正后的变形场表现出明显的空间异质性，在南冰原北部，隆升速率向南增加，最大值为40 mm/yr，而在南冰原边缘，隆升速率降至0 ~ 10 mm/yr。在东西方向上，西段的平均速度为12 mm/yr，与东段的25 mm/yr形成鲜明对比，在空间上与板窗边界一致。通过模拟当代冰融化的瞬态弹性变形，我们发现弹性分量仅占观测到的InSAR信号的23%。进一步进行了不同地幔黏度条件下的粘弹性变形建模，并与标定速度场拟合，确定了不同区域的最佳黏度设置。拟合结果证实了南北和东西方向的黏度差异，其特征为4个亚域，表现出3 × 1018 ~ 1.7 × 1019 Pa s的上地幔黏度变化。黏度非均质性为进一步细化三维流变结构提供了关键约束。我们的发现促进了更准确的区域GIA模型的发展，并有助于更好地理解潜在的地球动力学过程。

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引用次数: 0