Earth and Planetary Science Letters最新文献

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 : 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

Ultramafic float rocks at Jezero crater (Mars): excavation of lower crustal rocks or mantle peridotites by impact cratering? 耶泽罗陨石坑（火星）的超镁质浮岩：通过撞击陨石坑挖掘下地壳岩石或地幔橄榄岩？

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2025-12-04 DOI: 10.1016/j.epsl.2025.119746

O. Beyssac , E. Clavé , O. Forni , A. Udry , A.C. Pascuzzo , E. Dehouck , P. Beck , L. Mandon , C. Quantin-Nataf , N. Mangold , G. Lopez-Reyes , C. Royer , O. Gasnault , T.S.J. Gabriel , L. Kah , S. Schröder , J.R. Johnson , T. Bertrand , B. Chide , T. Fouchet , A. Cousin

Based on observation and data from meteorites and in situ scientific missions, experiments as well as models, the Martian mantle is assumed to share some compositional and mineralogical affinity with the terrestrial mantle. However, there might be subtle differences like the Martian mantle being more ferroan. Yet, we do not have any direct analysis of a Martian mantle rock to confirm this assumption. NASA’s Perseverance rover found olivine-rich boulder-sized float rocks on the upper Jezero fan (Mars). These boulders have an ultramafic composition and their mineralogy is dominantly composed of Fo_73±3 olivine with high-Mg orthopyroxene, Cr-rich Ti-Fe oxides and minor plagioclase and high-Ca pyroxene. Microtextural and petrological analysis reveals that these minerals crystallized at equilibrium. In addition, these boulders are different from all the bedrocks analyzed by Perseverance along its traverse which are crustal igneous rocks and sediments. Comparing our data to Martian meteorites and available Mars bulk silicate models (BSM), we discuss that these boulders could represent primitive melts and/or lower crustal material, and we specifically hypothesize that they could be mantle peridotites. We propose that these putative mantle rocks could have been excavated by the succession of impacts from the shallow mantle or lower crust in the Isidis region where Jezero crater is located. These olivine-rich boulders could thereby constitute the first direct analysis of a Martian mantle rock.

根据来自陨石的观测和数据以及实地科学任务、实验和模型，假设火星地幔与地球地幔在成分和矿物学上有一些相似之处。然而，可能会有细微的差异，比如火星地幔的铁含量更高。然而，我们没有对火星地幔岩石的任何直接分析来证实这一假设。美国宇航局的“毅力号”探测器在耶泽洛扇（火星）上部发现了富含橄榄石的巨石大小的浮石。这些巨石具有超镁铁质组成，其矿物学主要由Fo73±3橄榄石、高mg正辉石、富cr Ti-Fe氧化物和少量斜长石和高ca辉石组成。显微结构和岩石学分析表明，这些矿物在平衡状态下结晶。此外，这些巨石不同于“毅力号”沿途分析的所有基岩，它们都是地壳火成岩和沉积物。将我们的数据与火星陨石和现有的火星体积硅酸盐模型（BSM）进行比较，我们讨论了这些巨石可能代表原始熔体和/或下地壳物质，我们特别假设它们可能是地幔橄榄岩。我们认为，这些假定的地幔岩石可能是由耶泽罗陨石坑所在的伊西迪斯地区的浅层地幔或下地壳的连续撞击所挖掘出来的。因此，这些富含橄榄石的巨石可以构成对火星地幔岩石的第一次直接分析。

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引用次数: 0

Variable roles of oceanic transform faults in plume dispersion along segmented mid-ocean ridges 海洋转换断层在分段洋中脊羽散中的可变作用

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2025-12-04 DOI: 10.1016/j.epsl.2025.119766

Fan Zhang , Sibiao Liu , Lars H. Rüpke , Yiming Luo , Ming Chen , Xubo Zhang , Lei Zhao , Yinuo Zhang , Zhanying Chen , Jian Lin

Transform faults are integral to the mid-ocean ridge system, yet their role in modulating mantle plume dispersion along segmented ridges remains poorly understood. By compiling and analyzing the tectonic characteristics of 24 global plume–ridge–transform systems, we categorize them into three types: on-ridge, off-ridge, and on-transform–fracture zone interactions. Using 3D geodynamic models, we evaluate how transform fault length, plume–transform distance, plume–ridge distance, and spreading rate influence plume behavior. Our results reveal that transform faults can play three distinct roles in plume dispersion, depending on plume positioning relative to the ridge–transform system. Barrier-like behavior occurs when transform offset increases the separation between the plume and two ridge segments and plume material needs to cross the lithospheric discontinuity boundary along the transform fault to spread, thus strongly reducing along-ridge plume dispersion (e.g., on-ridge plumes and most off-ridge plumes beneath the outside corner of a ridge segment). Bridge-like behavior arises when plumes beneath fracture zones or near ridge–transform intersections bypass these discontinuities, enabling dispersion to both ridge segments with little reduction. Booster-like behavior emerges under certain geometries, such as inside-corner plumes or plumes beneath transform centers. In these scenarios, dispersion is enhanced by shorter plume–ridge distance, avoidance of lithospheric discontinuities, and localized strengthening of along-ridge mantle flow near the transform fault induced by strike-slip motion. These findings highlight the geometric controls on plume–ridge–transform interactions and underscore the complexity of transform fault influence in plume dynamics.

转换断层是大洋中脊系统的组成部分，但它们在调节沿分段脊的地幔柱弥散中的作用仍然知之甚少。通过对全球24个羽状脊-转换系统的构造特征进行整理和分析，将其划分为3种类型：脊上、脊外和转换-断裂带相互作用。利用三维地球动力学模型，我们评估了转换断层长度、羽流-转换距离、羽流-脊距离和扩散速率对羽流行为的影响。我们的研究结果表明，转换断层在羽流弥散中可以发挥三种不同的作用，这取决于相对于脊-转换系统的羽流定位。当转换偏移增加了羽流与两个脊段之间的分离，并且羽流物质需要沿着转换断层穿过岩石圈不连续边界才能扩散，从而强烈地减少了沿脊的羽流弥散（例如，脊上羽流和大部分脊外羽流位于脊段外角以下）时，就会出现类障壁行为。当断裂带下方的羽流或靠近山脊转换交叉处绕过这些不连续面时，就会出现桥状行为，从而使两个山脊段的弥散几乎没有减少。类似助推器的行为在某些几何形状下出现，例如内角羽流或变换中心下方的羽流。在这些情况下，较短的柱脊距离、避免岩石圈不连续以及走滑运动引起的转换断层附近沿脊地幔流动的局部增强增强了弥散。这些发现强调了羽状-脊状-转换相互作用的几何控制，并强调了转换断层对羽状动力学影响的复杂性。

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引用次数: 0

Long-term faulting history of the Central Taurides based on U-Pb dating of syn-tectonic calcites 基于同构造方解石U-Pb定年的中金牛纪长期断裂史

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2025-12-03 DOI: 10.1016/j.epsl.2025.119763

Tunahan Aykut , I. Tonguç Uysal , Cengiz Yıldırım , Timur Ustaömer , Nicole Leonard

The Central Taurides, located along the southern margin of the Central Anatolian Plateau (CAP), form a distinctive physiographic unit characterized by a steep mountain belt, high fault density, and diverse kinematic structures. It represents a key geological archive of subduction and the initial stages of collision in the Eastern Mediterranean. Although the geological evolution and origin of high-relief mountain development in this area remain extensively debated, the faulting history is poorly constrained due to a lack of direct isotopic age data. To comprehend the link between brittle deformation, uplift and plateau margin development, we investigate faulting history using kinematic and microstructural analyses combined with U-Pb dating of syn-tectonic calcites. U-Pb dating of forty-one syn-tectonic calcites indicate three faulting phases from the Late Cretaceous to the Quaternary. Thrust/reverse faulting occurred in the Late Cretaceous, followed by strike-slip faulting from the Early Eocene to the Early Miocene. Normal faulting became prevalent from the Early Miocene to the Quaternary. This study confirms compressional control on faulting during the Late Cretaceous in southern Türkiye. We also identify a previously unrecognized strike-slip faulting phase between the Early Eocene and the Early Miocene and demonstrate that extensional deformation in the Central Taurides began in the Early Miocene, rather than in the Middle/Late Miocene as suggested by earlier studies. Our results suggest that post-Oligocene structural patterns have been shaped by extensional processes. This study provides new constraints on multiple tectonic phases along the southern CAP margin, offering key insights into the geodynamic evolution of the Eastern Mediterranean.

中牛头构造群位于中安纳托利亚高原（CAP）南缘，形成了一个独特的地理单元，其特征是陡峭的山带、高断层密度和多样的运动结构。它代表了东地中海俯冲和碰撞初始阶段的重要地质档案。尽管本区高岭山发育的地质演化和成因仍有广泛的争论，但由于缺乏直接的同位素年龄资料，对断裂历史的了解很少。为了理解脆性变形、隆升和高原边缘发育之间的联系，我们利用运动学和微观结构分析结合同构造方解石的U-Pb测年研究了断裂历史。41个同构造方解石的U-Pb测年显示了晚白垩世至第四纪的三个断裂阶段。晚白垩世发育逆冲断裂，早始新世至早中新世发育走滑断裂。早中新世至第四纪，正断层活动盛行。本研究证实了晚白垩世南震旦系挤压作用对断裂的控制作用。我们还在早始新世和早中新世之间确定了一个以前未被认识的走滑断裂阶段，并证明了中牛力系的伸展变形始于早中新世，而不是早期研究认为的中新世中晚。研究结果表明，渐新世后的构造模式是由伸展作用形成的。该研究为CAP南部边缘的多构造阶段提供了新的约束，为东地中海的地球动力学演化提供了关键的见解。

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引用次数: 0

Orographic and convective precipitation control meteoric 10Be wet depositional fluxes at low latitude 地形和对流降水控制低纬度大气10Be湿沉积通量

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2025-12-03 DOI: 10.1016/j.epsl.2025.119759

Rose PAQUE , Angus MOORE , Jean L. DIXON , Marcus CHRISTL , Yessenia MONTES , Veerle VANACKER

Using meteoric ¹⁰Be (¹⁰Be_m) as a tracer of Earth surface processes requires understanding the factors that control ¹⁰Be_m depositional fluxes. How precipitation influences ¹⁰Be_m depositional fluxes is still debated, especially at low latitudes where little empirical flux data exist. To investigate how precipitation amount and type (drizzle vs. intense rain) influence meteoric ¹⁰Be depositional patterns in equatorial regions, we measured ¹⁰Be_m concentrations in rain across a 10-fold precipitation gradient on Santa Cruz Island in the Galápagos Archipelago (Ecuador) over one hydrological year. The island’s climate is characterized by a cool season, with aridity in the lowlands and persistent fog and drizzle in the highlands, and a warm season marked by localized, intense convective precipitation. Measured ¹⁰Be_m concentrations during the warm season decrease with increasing precipitation. Conversely, during the cool season ¹⁰Be_m concentrations increase with increasing precipitation. We attribute this behavior to dilution of ¹⁰Be_m concentrations during intense precipitation events in the warm season and enhanced efficiency of scavenging of ¹⁰Be_m bearing aerosols by fog droplets during the cool season. Overall, enhanced scavenging outweighs dilution, and annual fluxes show a greater-than-linear increase with precipitation. Our dataset demonstrates that ¹⁰Be_m concentrations in rain near the equator vary spatially and temporally as a function of precipitation type. We recommend taking atmospheric processes leading to cloud and fog formation into account when assessing wet depositional fluxes of ¹⁰Be_m, as these may enhance ¹⁰Be_m scavenging from the atmosphere.

利用大气10Be （10Bem）作为地球表面过程的示踪剂，需要了解控制10Bem沉积通量的因素。降水如何影响10Bem沉积通量仍然存在争议，特别是在缺乏经验通量数据的低纬度地区。为了研究降水量和降水类型（毛毛雨与强降雨）如何影响赤道地区的大气10Bem沉积模式，我们在一个水文年期间测量了Galápagos群岛（厄瓜多尔）圣克鲁斯岛10倍降水梯度的降雨中10Bem的浓度。该岛的气候特点是凉爽的季节，低地干旱，高原持续有雾和毛毛雨，温暖的季节以局部强烈的对流降水为特征。暖季测得的10Bem浓度随降水增加而降低。相反，在凉爽季节，bem浓度随着降水的增加而增加。我们将这种行为归因于暖季强降水事件对10Bem浓度的稀释，以及冷季雾滴对含10Bem气溶胶的清除效率提高。总的来说，增强的清除作用大于稀释作用，年通量随降水的增加大于线性。我们的数据表明，赤道附近降雨中的10Bem浓度作为降水类型的函数在空间和时间上都有变化。我们建议在评估10Bem的湿沉积通量时考虑导致云和雾形成的大气过程，因为这些过程可能会增强从大气中清除10Bem的能力。

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引用次数: 0

Colonial cold-water coral Li/Mg palaeothermometry: Influence of growth rate and skeletal heterogeneity 殖民地冷水珊瑚Li/Mg古温学：生长速率和骨骼异质性的影响

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2025-12-01 DOI: 10.1016/j.epsl.2025.119743

Qian (刘倩) Liu , Joseph A. Stewart , Laura F. Robinson , Sang Chen , Maoyu Wang , Tianyu Chen , Tao Li

Reconstructing past seawater temperatures is essential for understanding ocean circulation and climate linkages, prompting extensive efforts to develop geochemical temperature proxies in marine carbonates that extend records beyond instrumental observations. Trace element ratios in biogenic carbonates offer valuable insights into past ocean temperatures, yet their reliability hinges on a detailed understanding of the chemical heterogeneity within marine calcifiers and the underlying biomineralization mechanisms. This study calibrates Li/Mg, Li/Ca, and Mg/Ca ratios in the corallite (cup skeleton) and branch (i.e., coenosteum) of modern colonial cold-water scleractinian corals (Madrepora, Enallopsammia, Dendrophyllia, Solenosmilia), and uses a numerical biomineralization model to investigate the influence of physiological processes and growth rates on these proxies. We find a systematic offset of Li/Ca, Mg/Ca as well as Li/Mg between corallite and branch, with higher values observed in the corallite. Our results show that while a biocalcification model that assumes constant metal (Me) distribution coefficients (D_Me = Me/Ca_carbonate / Me/Ca_fluid) effectively captures the observed Me/Ca correlations, it fails to explain the consistent Li/Mg offset between corallite and branch in these colonial coral specimens. Instead, growth rate difference between corallite and branch might contribute to the consistent Li/Mg offset between the two skeleton structures, with lower growth rates corresponding to the branch. This insight is critical for palaeotemperature reconstructions using colonial corals, as applying a single Li/Mg – temperature calibration to both skeletal components can introduce systematic error. We highlight the need to differentiate between skeletal structures, especially in fossil materials where corallites are often degraded. Our study underscores the need for continued research to reduce the uncertainties associated with Li/Mg paleothermometry.

重建过去的海水温度对于理解海洋环流和气候之间的联系至关重要，这促使人们广泛努力开发海洋碳酸盐的地球化学温度代用物，将记录扩展到仪器观测之外。生物碳酸盐中的微量元素比例为过去的海洋温度提供了有价值的见解，但它们的可靠性取决于对海洋钙化物内部化学异质性和潜在生物矿化机制的详细了解。本研究校正了现代殖民地冷水硬核珊瑚（Madrepora, Enallopsammia, Dendrophyllia, Solenosmilia）的珊瑚（杯状骨架）和分支（即coenosteum）中的Li/Mg， Li/Ca和Mg/Ca比值，并使用数值生物矿化模型研究生理过程和生长速率对这些指标的影响。在珊瑚岩和树枝之间，Li/Ca、Mg/Ca和Li/Mg有系统的偏移，在珊瑚岩中观测到较高的数值。我们的研究结果表明，虽然假设恒定金属（Me）分布系数（DMe = Me/ carbonate / Me/Cafluid）的生物钙化模型有效地捕获了观察到的Me/Ca相关性，但它无法解释这些殖民地珊瑚标本中珊瑚岩和分支之间一致的Li/Mg偏移。相反，珊瑚岩和树枝的生长速率差异可能导致两种骨架结构的Li/Mg偏移一致，树枝对应的生长速率较低。这种见解对于使用群落珊瑚进行古温度重建至关重要，因为对两个骨骼组件应用单个Li/Mg温度校准可能会引入系统误差。我们强调需要区分骨骼结构，特别是在珊瑚岩经常退化的化石材料中。我们的研究强调需要继续研究以减少与Li/Mg古测温相关的不确定性。

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引用次数: 0

First radar evidence of large-scale englacial folding in the South Polar Layered Deposits (Ultimi Scopuli, Mars) unveiled by MARSIS 第一个雷达证据的大规模冰川折叠在南极层状沉积物（Ultimi Scopuli，火星）由MARSIS公布

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2025-11-30 DOI: 10.1016/j.epsl.2025.119749

L. Guallini , R. Orosei , E. Pettinelli , G. Caprarelli

Englacial folding is commonly observed in Greenland and Antarctica ice-sheets by Radar Echo Sounding (RES) technique. However, on Mars they had never been detected using sounding radars. Here we report the first observations of englacial folding within the Martian South Polar Layered Deposits (SPLD) using the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS). The SPLD are generally characterized by a planar-parallel sub-horizontal stratigraphy consisting of stacks of dusty water ice layers. In this work we present and discuss low- or no-reflectivity areas (NRAs) observed in MARSIS radargrams acquired over Ultimi Scopuli: the NRAs disrupt or interrupt the sub-horizontal stratigraphy. In the radargrams, the NRAs appear as round or elliptic shaped dark areas approximately 10-15 km wide (along track) developing from the base of the SPLD, and extending vertically for hundreds of meters, in some cases across almost the entire thickness of the deposits (∼1.5 km). The dark areas are related to bright reflectors curving or tilting around and/or inside the NRAs and forming folding structures ranging from antiforms to asymmetric or convolute folding. These structures resemble those observed by RES on Earth. Based on our observations, we posit that: (1) the dark areas in the radargrams are produced by destructive interference of the propagating radar waves caused by tight folding of high angle dipping strata; and, (2) the deformed layers within or on the outside of the NRAs are the englacial fold system. The presence of englacial folds would indicate differential sliding and/or flowing of the ice sheet over the bedrock.

通过雷达回波探测（RES）技术，可以在格陵兰岛和南极洲的冰盖上观测到英格兰褶皱。然而，在火星上，探测雷达从未探测到它们。本文报道了利用火星先进雷达探测火星地下和电离层（MARSIS）首次观测到的火星南极层状沉积物（SPLD）内部的冰川褶皱。SPLD的一般特征是由堆积的含尘水冰层组成的平面平行亚水平地层。在这项工作中，我们提出并讨论了在Ultimi Scopuli上获得的MARSIS雷达图中观察到的低反射率或无反射率区域（NRAs）： NRAs破坏或中断了亚水平地层。在雷达图中，nra呈现为圆形或椭圆形的黑暗区域，宽约10-15公里（沿着轨道），从SPLD的底部开始发展，垂直延伸数百米，在某些情况下几乎覆盖了整个沉积物的厚度（约1.5公里）。暗区与明亮的反射体在nra周围和/或内部弯曲或倾斜有关，并形成从反形到不对称或卷曲折叠的折叠结构。这些结构类似于RES在地球上观测到的结构。根据我们的观察，我们认为：(1)雷达图中的暗区是由高倾角地层紧密褶皱引起的雷达波传播的相消干涉造成的；(2) nra内部或外部的变形层为冰川褶皱体系。冰川褶皱的存在表明冰盖在基岩上有不同的滑动和/或流动。

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引用次数: 0

Quantifying changes in central Vietnam rainfall amount since the Late Pleistocene 越南中部晚更新世以来降雨量的量化变化

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2025-11-29 DOI: 10.1016/j.epsl.2025.119758

Elizabeth W. Patterson , Alliya A. Akhtar , Michael L. Griffiths , David McGee , Quốc Đỗ-Trọng , Annabel Wolf , John A. Higgins , Stefania Gili , Mùi X. Trần , Hùng Q. Nguyễn , Trí H. Đinh , Thành N. Bùi , Kathleen R. Johnson

Paleorecords of the Southeast Asian autumn monsoon indicate that global sea-level change drove abrupt shifts in rainfall, yet the magnitude of these changes remains unquantified. Using δ⁴⁴Ca and Mg/Ca measurements from a speleothem from central Vietnam, we generate semi-quantitative rainfall records spanning 45–4 ka. When compared to modern rainfall, our results reveal a ∼50–60 % reduction in rainfall during the Last Glacial Maximum (LGM), associated with the sea-level lowstand. While climate models and a data assimilation product (PMIP4-CMIP6, iTRACE, DAMP-21ka) also show LGM drying (annual model mean = 8.5 % drier), the coarse spatial resolution of the models does not resolve the north-south trending Truong Son Mountains, an orographic barrier that blocks summer rainfall from reaching central Vietnam and enhances autumn rainfall. This causes a causes a summer rainfall wet bias in the models leading to an underestimation of annual rainfall change. However, simulations of autumn rainfall show better agreement with speleothem proxies (autumn model mean = 29 % drier), demonstrating that the models broadly capture changes in autumn monsoon rainfall amount. These findings underscore the sensitivity of the Southeast Asian autumn monsoon to sea-level change and highlight the value of using speleothem δ⁴⁴Ca and Mg/Ca to validate climate model simulations of rainfall amount.

东南亚秋季季风的古记录表明，全球海平面的变化导致了降雨量的突变，但这些变化的幅度仍然无法量化。利用来自越南中部洞穴的δ⁴Ca和Mg/Ca测量值，我们生成了跨越45-4 ka的半定量降雨记录。与现代降雨相比，我们的研究结果显示，末次盛冰期（LGM）的降雨量减少了~ 50 - 60%，这与海平面低潮点有关。虽然气候模式和数据同化产品（PMIP4-CMIP6, iTRACE, DAMP-21ka）也显示LGM干燥（年模式平均=干燥8.5%），但模式的粗空间分辨率不能解决南北走向的张山，这是一个地形障碍，阻止夏季降雨到达越南中部并增强秋季降雨。这导致模式中的夏季降雨偏湿，导致对年降雨量变化的低估。然而，秋季降雨的模拟结果与洞穴模拟结果（秋季模式平均值=干燥29%）更加吻合，表明这些模式广泛地捕捉到了秋季季风降雨量的变化。这些发现强调了东南亚秋季季风对海平面变化的敏感性，并强调了使用洞穴测量δ⁴Ca和Mg/Ca来验证气候模式对降雨量模拟的价值。

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引用次数: 0

Source and evolution of 4.0 – 3.9 Ga crust revealed by U-Pb, Lu-Hf and trace element analyses of xenocrystic zircon, Superior Province 由异晶锆石U-Pb、Lu-Hf及微量元素分析揭示了苏必略省4.0 ~ 3.9 Ga地壳的来源与演化

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2025-11-29 DOI: 10.1016/j.epsl.2025.119764

J.W.D. Strong , D.W. Davis , J. Marsh , P.C. Thurston , A.J.M. Lalonde , J.M. Simmons , K. Ross

In the Superior Province, Eoarchean magmatism sourced from partially melted Hadean mafic crust has been inferred from published ca. 3.9 Ga detrital zircon Hf isotope compositions and whole-rock ¹⁴²Nd isotopes. We report simultaneously acquired U-Pb/Lu-Hf and U-Pb/trace element analyses of 4.0 – 3.9 Ga xenocrystic zircon grains from a polyphase gneiss that provide direct evidence for Eoarchean partial melting of Hadean crust in the Hudson Bay terrane, Superior Province. Zircon domains record age groups at ca. 3.99 – 3.94 Ga, 3.92 – 3.84 Ga, 3.59 Ga, 3.48 Ga, 3.32 Ga, 3.27 Ga, 3.1 – 2.95 Ga, 2.84 Ga and 2.73 Ga. The ca. 3.99 – 3.84 Ga core domains have subchondritic Hf isotope signatures yielding an estimated mantle extraction age between 4.23 Ga and 4.18 Ga. The ca. 3.92 – 3.84 Ga zircon core and mantle domains are faintly or homogeneously zoned (ghost zonation), they inherited the Hf isotope compositions of the older ca. 3.99 – 3.94 Ga protolithic grains, and have trace element signatures consistent with expulsion of LREE over HREE and Th over U, which altogether reflect solid-state recrystallization of the older protolith zircon population. The mechanism for solid-state recrystallization requires a high-grade metamorphic event. Therefore, the ca. 3.92 – 3.84 Ga zircon population appears to record the earliest known metamorphic event on Earth, which was previously identified and inferred from detrital zircon in the Jack Hills meta-conglomerate.

根据已公布的约3.9 Ga碎屑锆石Hf同位素组成和全岩142同位素组成推断，上古宙岩浆活动来源于部分熔融的冥古宙基性地壳。本文报道了一多相片麻质4.0 ~ 3.9 Ga异晶锆石颗粒的U-Pb/Lu-Hf和U-Pb/微量元素同步分析，为苏伯里尔省哈德逊湾地体早太古代冥古宙地壳部分熔融提供了直接证据。锆石域记录的年龄分别为3.99 ~ 3.94 Ga、3.92 ~ 3.84 Ga、3.59 Ga、3.48 Ga、3.32 Ga、3.27 Ga、3.1 ~ 2.95 Ga、2.84 Ga和2.73 Ga。约3.99 ~ 3.84 Ga的核域具有亚球粒状Hf同位素特征，估计地幔提取年龄在4.23 ~ 4.18 Ga之间。3.92 ~ 3.84 Ga锆石核幔域呈微弱或均匀分带（鬼带），继承了3.99 ~ 3.94 Ga古原石颗粒的Hf同位素组成，微量元素特征与LREE / HREE、Th / U排出相一致，反映了古原石锆石种群的固态再结晶。固态再结晶的机理需要高变质作用。因此，约3.92 - 3.84 Ga的锆石群似乎记录了地球上已知最早的变质事件，这是先前从杰克山变质砾岩的碎屑锆石中确定和推断出来的。

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引用次数: 0

The role of thermo-poro-elastic effects in the interpretation of gravity data 热孔弹性效应在重力资料解释中的作用

IF 4.8 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Earth and Planetary Science Letters

Pub Date : 2025-11-26 DOI: 10.1016/j.epsl.2025.119762

Massimo Nespoli, Maurizio Bonafede, Maria Elina Belardinelli

The study of gravity changes induced by magma chambers in volcanic environments has long been used to monitor unrest phases and to estimate the volumes and masses of magma intrusions. However, magma is not the sole driver of the observed deformation and gravity changes. Hydrothermal systems within the volcanic structure can also play a significant role. Recent advances in Thermo-Poro-Elastic (TPE) inclusion models have made it possible to efficiently and accurately simulate the mechanical effects caused by an increase of temperature and pore-pressure of fluids in a reservoir. In this work, we calculate the gravity variations induced by a disk-shaped inclusion. We model gravity variations induced by increments of pore-pressure and temperature within different fluid phases. We also consider the superposition of the effects of a TPE inclusion with a deeper magma chamber. The comparison with the data measured at the Campi Flegrei caldera (Italy) allows us to draw some suggestions on the use and interpretation of these results. Our findings demonstrate that these effects are significant and cannot be overlooked when interpreting gravimetric data during unrest phases and to assess geohazard levels.

长期以来，火山环境中岩浆房引起的重力变化研究一直被用于监测不稳定阶段和估计岩浆侵入的体积和质量。然而，岩浆并不是观测到的变形和重力变化的唯一驱动因素。火山构造内部的热液系统也可以发挥重要作用。热-孔隙弹性（TPE）包裹体模型的最新进展，使得有效、准确地模拟储层流体温度和孔隙压力升高所引起的力学效应成为可能。在这项工作中，我们计算了由圆盘状包裹体引起的重力变化。我们模拟了不同流体相中孔隙压力和温度增量引起的重力变化。我们还考虑了TPE包裹体与更深岩浆房的叠加效应。与Campi Flegrei火山口（意大利）测量的数据进行比较，使我们能够对这些结果的使用和解释提出一些建议。我们的研究结果表明，这些影响是显著的，在解释动荡阶段的重力数据和评估地质灾害水平时不能忽视。

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引用次数: 0