Geology最新文献_第4页

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

Mobilization of insoluble Fe(III) and phosphate in sulfate- and carbonate-rich fluids 在富含硫酸盐和碳酸盐的液体中不溶性铁（III）和磷酸盐的动员

IF 5.8 1区地球科学

Geology Pub Date : 2026-07-09 DOI: 10.1130/g54368.1

Huan Chen, Richen Zhong, Yuling Xie, Xinfu Zhao, Joël Brugger, Hao Cui, Chang Yu, Mojie Li

引用次数: 0

Middle Pleistocene (>350 ka) glaciation in the Carpathians unveiled by quartz microtextures from cave sediments (Low Tatra Mountains, Slovakia) 喀尔巴阡山脉中更新世（bb0 ~ 350 ka）冰川作用：洞穴沉积物的石英显微结构揭示（斯洛伐克低塔特拉山脉）

IF 5.8 1区地球科学

Geology Pub Date : 2026-07-08 DOI: 10.1130/g54825.1

Dawid Siemek, Jacek Szczygieł, Barbara Woronko, Juraj Littva, Pavel Bella, Piotr Kłapyta

引用次数: 0

Presubduction heavy Mg isotope enrichment in the sub-arc mantle 弧下地幔俯冲前重Mg同位素富集

IF 5.8 1区地球科学

Geology Pub Date : 2026-07-06 DOI: 10.1130/g54265.1

Yuxiang Zhang, Yi-Xiang Chen, Zuxing Chen, Fang Huang, Maoyong He, Zhigang Zeng

{"title":"Presubduction heavy Mg isotope enrichment in the sub-arc mantle","authors":"Yuxiang Zhang, Yi-Xiang Chen, Zuxing Chen, Fang Huang, Maoyong He, Zhigang Zeng","doi":"10.1130/g54265.1","DOIUrl":"https://doi.org/10.1130/g54265.1","url":null,"abstract":"Arc lavas with heavier magnesium (Mg) isotope ratios (denoted as δ26Mg) compared to mid-ocean-ridge basalt (MORB) are commonly attributed to the involvement of subducted serpentinite. However, this hypothesis is challenged by the widespread absence of high-δ26Mg serpentinite in the subducting plates beneath Pacific arcs and fails to consider potential δ26Mg heterogeneity in ambient arc mantle. Here, we show that backarc lavas from the Mariana and Ryukyu subduction zones have MORB-like boron (B) isotope compositions and B/Nb ratios, indicative of little subducted serpentinite in their source. Such lavas have similarly high δ26Mg as their arc counterparts, suggesting the ambient arc mantle in this area is intrinsically rich in isotopically heavy Mg. Further analysis of metaserpentinites demonstrates that deserpentinization residues inherit protolith δ26Mg without significant isotope fractionation during dehydration, highlighting the important contribution of deserpentinized peridotite to the high-δ26Mg mantle. We propose that the high-δ26Mg arc lavas are not necessarily related to ongoing serpentinite subduction, especially in fast-spreading ridge systems. On the other hand, long-term recycling of ancient high-δ26Mg serpentinite provides one plausible mechanism for the heavy Mg mantle domain identified beneath the arc systems. This potentially widespread domain in the mantle greatly affects long-term Mg recycling and crust-mantle evolution.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"22 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148415187","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

Meteoritic and hydrothermal sources of reduced phosphorus in the early Archean 太古宙早期还原磷的陨石和热液来源

IF 5.8 1区地球科学

Geology Pub Date : 2026-06-25 DOI: 10.1130/g54384.1

Joanna Kalita, Abu S. Baidya, Nadja Drabon, Eva E. Stüeken

引用次数: 0

Independent evolution of Gondwana terranes along its northern margin during early Tethyan initiation 特提斯早期形成时期冈瓦纳地体沿其北缘的独立演化

IF 5.8 1区地球科学

Geology Pub Date : 2026-06-02 DOI: 10.1130/g54872.1

Mingjun Zheng, Jun Deng, Yongjun Lu, Huanchao Xu, Jiale Wang, Yingjie Wang, Xianyi Huang, Ke Miao, Xiang Sun

{"title":"Independent evolution of Gondwana terranes along its northern margin during early Tethyan initiation","authors":"Mingjun Zheng, Jun Deng, Yongjun Lu, Huanchao Xu, Jiale Wang, Yingjie Wang, Xianyi Huang, Ke Miao, Xiang Sun","doi":"10.1130/g54872.1","DOIUrl":"https://doi.org/10.1130/g54872.1","url":null,"abstract":"The late Ediacaran−early Paleozoic (580−420 Ma) represents a critical interval marked by the final Gondwana assembly and initiation of the Tethyan realm. The Lhasa terrane (southwestern China) is commonly regarded as part of the Indo-Australian margin tectonic system, yet its paleogeographic affinity and tectono-magmatic evolution remain debated. Here we present a systematic comparison of geological records from the Lhasa terrane with those from the South Qiangtang, Himalaya, and Sibumasu terranes as well as the Iran-Anatolia region. Our results reveal significant differences in tectono-magmatic evolution among terranes along the northern margin of Gondwana. The Lhasa terrane records a prolonged subduction-related history from 580 to 480 Ma, comparable to that of the Iran-Anatolia region, including low-angle subduction at 570−525 Ma, slab rollback at 525−510 Ma, and terrane accretion accompanied by slab break-off at 510−480 Ma. In contrast, terranes along the Indo-Australian margin record a coherent two-stage evolution, with 550−520 Ma ocean-island basalt−like magmatism related to the postcollisional extension stage of the Kuunga-Pinjarra orogen, followed by 500−420 Ma arc-backarc magmatism linked to Proto-Tethyan subduction. These contrasts demonstrate that the Lhasa terrane was not part of the Indo-Australian margin but evolved independently along the African margin of Gondwana, an interpretation further supported by metamorphic and detrital-zircon evidence. Our results refine the geodynamic framework of early Tethyan evolution, provide new constraints on the paleogeographic reconstruction of East Asian blocks, and offer insight into the spatial heterogeneity of Phanerozoic tin mineralization.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"170 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148289493","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