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Coseismic dilatancy controlling thermal pressurization efficiency and fluid redistribution in clay-rich fault gouge 同震膨胀控制富泥断层泥热压效率和流体重分布

IF 5.8 1区地球科学

Geology Pub Date : 2026-09-04 DOI: 10.1130/g55073.1

Dohee Gu,Raehee Han,Chang-Min Kim

{"title":"Coseismic dilatancy controlling thermal pressurization efficiency and fluid redistribution in clay-rich fault gouge","authors":"Dohee Gu,Raehee Han,Chang-Min Kim","doi":"10.1130/g55073.1","DOIUrl":"https://doi.org/10.1130/g55073.1","url":null,"abstract":"Thermal pressurization driven by frictional heating is a potentially important dynamic weakening mechanism in low-permeability clay-rich fault gouge, producing reduced frictional resistance with limited temperature rise. However, geological evidence of high-temperature coseismic processes recorded in such fault rocks suggests that mechanisms capable of reducing the effectiveness of thermal pressurization have also operated. Here, we report coseismic dilatancy in foliated gouge from the Yangsan fault, a large strike-slip fault in southeastern Korea, and discuss its implications for thermal pressurization efficiency and fluid redistribution. Our observations include gouge injection structures (IV type) penetrating into the surrounding rock, foliation opening structures (F type) within the gouge, and calcite aggregates precipitated within these structures. The IV type is interpreted to record coseismic extension fracturing of the surrounding rock under fault-parallel dynamic tension, whereas the F type is inferred to reflect the opening of foliation driven by thermal pressurization. The formation of these structures may have caused a rapid drop in fluid pressure, potentially diminishing the effectiveness of thermal pressurization and promoting fluid redistribution. Our findings suggest that gouge foliation, while acting as a fluid flow barrier that promotes thermal pressurization, may simultaneously serve as a mechanically weak plane that, once opened during seismic slip, reduces its efficiency by providing a pathway for fluid flow. Notably, the postseismically precipitated calcite aggregates within these coseismic opening structures may represent promising targets for directly constraining the timing of past seismic slip using U-Pb or U-series dating.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"138 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A segmented high Gangdese arc before the India−Eurasia collision from triple oxygen isotope paleoaltimetry 从三氧同位素古海拔测定结果看，印度-欧亚大陆碰撞前的高冈底斯弧

IF 5.8 1区地球科学

Geology Pub Date : 2026-09-03 DOI: 10.1130/g54523.1

Xiang-Rui Liu,Jin-Gen Dai,Ji-Quan Chen,Daniel E. Ibarra,Xiao-Bin Cao,Song Wu,Guang-Sheng Ren,Yuan Gao,Xu Han,Bo-Rong Liu,Jia-Qi Sun,Cheng-Shan Wang

{"title":"A segmented high Gangdese arc before the India−Eurasia collision from triple oxygen isotope paleoaltimetry","authors":"Xiang-Rui Liu,Jin-Gen Dai,Ji-Quan Chen,Daniel E. Ibarra,Xiao-Bin Cao,Song Wu,Guang-Sheng Ren,Yuan Gao,Xu Han,Bo-Rong Liu,Jia-Qi Sun,Cheng-Shan Wang","doi":"10.1130/g54523.1","DOIUrl":"https://doi.org/10.1130/g54523.1","url":null,"abstract":"Quantifying the paleoelevation of the Tibetan Plateau is critical for understanding its tectonic evolution, yet direct quantitative constraints on the past elevations of high mountain ranges remain sparse. We applied triple oxygen isotope (Δ′17O) paleoaltimetry to hydrothermal quartz from the Gangdese arc in southern Tibet to reconstruct Late Cretaceous−Paleogene meteoric water composition. Our results indicate that elevations of ∼3.2−4.7 km were already established along the Gangdese arc between ca. 77 Ma and 59 Ma, prior to the India−Eurasia collision. Integrated with previous isotope-based paleoelevation records, our data reveal that the pre-collisional Gangdese evolved as a segmented mountain belt, with elevated and comparatively lower sectors coexisting along strike rather than forming either a laterally uniform arc or a simple east-west topographic gradient. By providing direct constraints on surface elevation, our study offers a revised framework for reconstructing pre-collisional Gangdese topography and demonstrates the value of Δ′17O paleoaltimetry for resolving spatial variations in ancient mountain belts.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"10 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Tectonic escape from the Pangean megamonsoon via oceanic isolation modulated low-latitude hydroclimate 大洋隔离对泛古大陆特大季风的构造逃逸调节了低纬度水文气候

IF 5.8 1区地球科学

Geology Pub Date : 2026-09-03 DOI: 10.1130/g55065.1

Qiang Ren,Huaichun Wu,Anqing Chen,Jian Zhang,Zhuwei Wang,Shihong Zhang,Tianshui Yang,Haiyan Li,Hanting Zhong,Haipeng Li,James G. Ogg,Mingcai Hou

{"title":"Tectonic escape from the Pangean megamonsoon via oceanic isolation modulated low-latitude hydroclimate","authors":"Qiang Ren,Huaichun Wu,Anqing Chen,Jian Zhang,Zhuwei Wang,Shihong Zhang,Tianshui Yang,Haiyan Li,Hanting Zhong,Haipeng Li,James G. Ogg,Mingcai Hou","doi":"10.1130/g55065.1","DOIUrl":"https://doi.org/10.1130/g55065.1","url":null,"abstract":"The assembly of the Pangea supercontinent during the late Paleozoic ice age drove Earth’s most intense megamonsoon. Although climate models predict a humid low-latitude eastern Pangean margin, widespread red-bed records indicate extreme seasonal oxidation, creating a conspicuous “model-sediment” paradox. Located directly on this margin, the Xilinhot-Songliao block captures a “red-gray-red” sedimentary cycle that physically toggled between these conflicting arid and humid states. Here, we report ca. 315 Ma high-quality paleomagnetic data from the block to reconstruct its full drift trajectory (315−265 Ma). Integrated with geological proxies, the block is inferred to have maintained a close tectonic affinity with the Pangean margin initially (ca. 315 Ma), hosting megamonsoon-dominated red beds. Following the expansion of the Hegenshan Ocean to a N-S width of ∼2300 km by ca. 300 Ma, the block underwent “tectonic decoupling,” transitioning into a stable zonal climate depositing pure carbonates. Subsequent reattachment to the supercontinent (280−265 Ma) triggered a rapid reversion to arid megamonsoonal conditions. Occurring under a constant global icehouse, this “red-gray-red” oscillation demonstrates that tectonic distance to the supercontinent acted as the primary switch modulating land-sea thermal feedback. Our findings challenge paradigms relying solely on global climate cycles, highlighting how ocean basin evolution independently reshapes regional climatic landscapes.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"29 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Paleoproterozoic thermogenic hydrocarbon generation, Zaonega Formation, Russia 俄罗斯早奥涅加组古元古代热生烃

IF 5.8 1区地球科学

Geology Pub Date : 2026-07-13 DOI: 10.1130/g54338.1

Nivedita Thiagarajan, Aivo Lepland, Florian Eichinger, Anthony Prave, John Eiler

引用次数: 0

Full-length oceanic spreading in the Red Sea: Insights from the spatiotemporal distribution of earthquakes 红海的全程海洋扩张：地震时空分布的启示

IF 5.8 1区地球科学

Geology Pub Date : 2026-07-10 DOI: 10.1130/g54723.1

Ran Issachar, Nadav Wetzler, Shaked Engelberg, Meir Abelson

{"title":"Full-length oceanic spreading in the Red Sea: Insights from the spatiotemporal distribution of earthquakes","authors":"Ran Issachar, Nadav Wetzler, Shaked Engelberg, Meir Abelson","doi":"10.1130/g54723.1","DOIUrl":"https://doi.org/10.1130/g54723.1","url":null,"abstract":"The Red Sea is an embryonic ocean, offering a rare window into the early evolution of oceans. While the central-southern segment exhibits well-developed oceanic spreading, the tectonic regime of the northern Red Sea remains uncertain, specifically whether it still undergoes continental extension or has already transitioned to oceanic spreading. Thick sediment cover in the northern segment conceals direct evidence of oceanic crust formation. To address this, we examined the spatiotemporal distribution characteristics of more than10,000 earthquakes from a standardized International Seismological Centre (ISC) catalog (1960−2024). We found that seismicity is focused in a narrow zone along the Red Sea axis, and that the activity is overwhelmingly dominated by earthquake swarm sequences focused at distinct zones along the spreading axis. This pattern is typical of other (ultra)slow oceanic spreading centers globally, contrasting with the wider main shock−aftershock behavior expected in continental rifts. Furthermore, the seismological characteristics, including the spatial distribution of earthquakes, the typical swarm activity, and the overall b values, are comparable between the northern and central-southern segments of the Red Sea. We further found that earthquake swarms repeatedly occur in spatial association with bathymetric deeps, confirming these are active volcanic centers. This observation is also valid in the northernmost deeps despite the lack of exposed basaltic crust. Our comprehensive seismic analysis strongly supports the conclusion that active oceanic spreading extends along the entire length of the Red Sea.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"31 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148415613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Revealing hidden order in Pacific Ocean volcanism 揭示太平洋火山活动的隐藏规律

IF 5.8 1区地球科学

Geology Pub Date : 2026-07-10 DOI: 10.1130/g54800.1

Yanghui Zhao, Bryan Riel, Jiangyang Zhang, Gillian R. Foulger

{"title":"Revealing hidden order in Pacific Ocean volcanism","authors":"Yanghui Zhao, Bryan Riel, Jiangyang Zhang, Gillian R. Foulger","doi":"10.1130/g54800.1","DOIUrl":"https://doi.org/10.1130/g54800.1","url":null,"abstract":"The ca. 47 Ma Hawaiian-Emperor bend shows that early Cenozoic plate reorganization affected individual volcanic lineaments, but whether Pacific volcanism responded coherently at the basin scale has remained unknown. Fewer than 5% of Pacific Ocean seamounts have been aged radiometrically, and those ages cluster along accessible lineaments, biasing the basin-wide record toward lineament behavior. We used machine learning to predict ages for ∼4300 seamounts and to reconstruct basin-wide volcanic evolution. Volcanism peaked in the Late Cretaceous, declined through the early Cenozoic, and reached a minimum at 42.5 ± 6.5 Ma, tracking a sustained ca. 85−43 Ma plate reorganization that simplified the basin from a multi-ridge to a single East-Pacific-Rise−dominated configuration. The apparent ca. 45 Ma concentration of dated seamounts records localized lineament volcanism during this quiet interval rather than a basin-wide peak. Both lineament and scattered seamount populations transitioned from diffuse to spatially organized patterns, indicating a coherent basin-wide volcanic response to plate reorganization and first-order control by ridge configuration on Pacific intraplate volcanism.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"445 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148415617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Zinc isotope constraints on carbon cycle perturbations during the Cambrian radiation of animals 寒武纪动物辐射期间碳循环扰动的锌同位素约束

IF 5.8 1区地球科学

Geology Pub Date : 2026-07-10 DOI: 10.1130/g54342.1

Yang Liu, Sheng-Ao Liu, Susan H. Little, Ruoyuan Qiu, Mingyu Zhao, Xuan Tang, Simon W. Poulton

{"title":"Zinc isotope constraints on carbon cycle perturbations during the Cambrian radiation of animals","authors":"Yang Liu, Sheng-Ao Liu, Susan H. Little, Ruoyuan Qiu, Mingyu Zhao, Xuan Tang, Simon W. Poulton","doi":"10.1130/g54342.1","DOIUrl":"https://doi.org/10.1130/g54342.1","url":null,"abstract":"Increased oxygen and nutrient availability were likely crucial drivers of the Cambrian radiation of animals. However, productivity dynamics in the early Cambrian, and hence links to both metazoan radiation and global carbon cycle perturbations, remain poorly constrained. Zinc isotopes (δ66Zn) in marine sediments have emerged as a proxy for tracing productivity-induced perturbations to the carbon cycle. Here, we report δ66Zn data from two early Cambrian (ca. 522−514 Ma) siliciclastic successions on the Yangtze block, South China. Both sites show a major positive seawater δ66Zn excursion across the Cambrian Stage 2−3 boundary, synchronous with a global positive carbonate-carbon isotope (δ13Ccarb) shift. We interpret these concurrent excursions to reflect enhanced primary productivity and increased burial of isotopically light Zn in organic-rich sediments. Biogeochemical box modeling reproduces the observed δ66Zn−δ13Ccarb covariation, supporting coupled P-Zn-C cycling, in which elevated shallow-marine phosphorus (P) concentrations strengthened the biological pump and enhanced the removal of isotopically light Zn from seawater. Subsequently, reduced shallow-marine P concentrations and progressive ocean oxygenation collectively contributed to a decrease in seawater δ66Zn, either through reduced burial of isotopically light Zn in organic-rich sediments or the remobilization of previously buried isotopically light Zn. Together, our approach provides quantitative evidence that nutrient redistribution and productivity feedbacks governed early Cambrian Zn-C isotope dynamics, shedding light on the ecological backdrop of metazoan diversification.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"34 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148415612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Initiation of the modern tectonic architecture in southeastern Tibet 西藏东南部现代构造建筑的开端

IF 5.8 1区地球科学

Geology Pub Date : 2026-07-10 DOI: 10.1130/g54757.1

Jingxing Yu, Dewen Zheng, Ying Wang, Jianzhang Pang, Yifei Li, Huiping Zhang, Peizhen Zhang

引用次数: 0

Sequential serpentinization reactions revealed by boron isotope systematics of the Lost City vent fluids 失落之城喷口流体硼同位素系统揭示的连续蛇纹石化反应

IF 5.8 1区地球科学

Geology Pub Date : 2026-07-10 DOI: 10.1130/g54880.1

Aled D. Evans, Heather J. Goring-Harford, Rosalind M. Coggon, Rachael H. James, Caitlin McCarthy, Matthew J. Cooper, Gavin L. Foster, Gretchen L. Früh-Green, Susan Q. Lang, Damon A.H. Teagle

{"title":"Sequential serpentinization reactions revealed by boron isotope systematics of the Lost City vent fluids","authors":"Aled D. Evans, Heather J. Goring-Harford, Rosalind M. Coggon, Rachael H. James, Caitlin McCarthy, Matthew J. Cooper, Gavin L. Foster, Gretchen L. Früh-Green, Susan Q. Lang, Damon A.H. Teagle","doi":"10.1130/g54880.1","DOIUrl":"https://doi.org/10.1130/g54880.1","url":null,"abstract":"Hydrothermal vent fluids reflect interactions between oceanic lithosphere and seawater, but to date, the processes resulting in unusual hyperalkaline (up to pH 11) fluids venting ultramafic-hosted systems, such as the Lost City Hydrothermal Field, remain enigmatic. To elucidate fluid reaction pathways, we present boron (B) concentration and isotope analyses from fluids venting the Lost City, located off axis atop the serpentinized Atlantis Massif just west of the Mid-Atlantic Ridge at 30°N. Our data reveal that fluid B concentrations are markedly lower and isotopically lighter than that of seawater. These data contrast with the accepted understanding of B isotope systematics that predicts that the progressive removal of B from seawater during serpentine formation should result in low-B fluids with δ11B values higher than that of seawater. We utilize a mechanistic B isotope fractionation model coupled with a Bayesian inversion approach to robustly evaluate fluid-rock interactions and propose that Lost City fluid B compositions reflect a two-step process. Initially, B is progressively removed from seawater during serpentine formation, resulting in the generation of an effectively B-free serpentinizing fluid. Subsequently, B remobilized from previously formed serpentine is transferred to later fluids, resulting in the low-δ11B end-member values analyzed. Such an evolution demonstrates that fluid-rock interactions both add fluid-mobile elements such as B to mantle peridotites as well as remobilize them. Thus, analyzed serpentine δ11B signatures reflect the cumulative impact of B-consuming serpentinization and later B-remobilizing serpentinite recrystallization. Consequently, serpentinite alteration, in addition to serpentinization hydration reactions, actively contributes to chemical exchange between the mantle and the oceans.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"41 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148415616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

When and how Fe-oxide nanocrystals form: Insights from in situ FE-SEM and implications for eruption dynamics 铁氧化物纳米晶体何时以及如何形成：来自原位FE-SEM的见解和喷发动力学的含义

IF 5.8 1区地球科学

Geology Pub Date : 2026-07-09 DOI: 10.1130/g54466.1

Mayumi Mujin, Michihiko Nakamura

{"title":"When and how Fe-oxide nanocrystals form: Insights from in situ FE-SEM and implications for eruption dynamics","authors":"Mayumi Mujin, Michihiko Nakamura","doi":"10.1130/g54466.1","DOIUrl":"https://doi.org/10.1130/g54466.1","url":null,"abstract":"Nanocrystals (nanolites and ultrananolites) in volcanic rocks have attracted considerable attention owing to their potential role in increasing magma viscosity and serving as heterogeneous nucleation sites for bubbles, thereby influencing eruption styles. However, the conditions, time scales, and mechanisms of their formation remain poorly constrained. In this study, we conducted high-temperature, in situ observations of crystallization in a rhyolitic silicate melt using field-emission scanning electron microscopy. Nucleation of fine-grained Fe-oxide crystals (≤100 nm in width and diameter) occurred at high number densities (∼1020−1021 m−3) under sub-solidus and oxidizing conditions, whereas their growth into coarser nanolites was not observed. The fastest case of beginning crystallization was ∼35 s after the melt reached the target temperature. Under above-solidus conditions, nucleation occurred at substantially lower number densities (≤∼1019 m−3) and crystal growth dominated with time. Nucleation under sub-solidus and oxidizing conditions was likely facilitated by spinodal-type liquid immiscibility between Fe-rich and Fe-poor melts. These results suggest that high-number-density ultrananolites formed through liquid immiscibility may serve as indicators of shallow magmatic processes but are unlikely to control the occurrence of Plinian eruptions in deep conduits. Rapid nucleation of Fe-oxide ultrananolites could allow their detection in pumice from explosive eruptions.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"53 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148415128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0