IF 5.8 1区地球科学

Geology Pub Date : 2025-09-10 DOI: 10.1130/g53449.1

Jonathan Obrist-Farner, Jeremy Maurer, Derek Gibson, Trenton McEnaney, Andreas Eckert, William F. Kenney, Jeffery Beeson, Nigel Wattrus, Quin Stangeland, Fatima Reyes

引用次数: 0

Oxygen isotopes in cherts record paleo−heat flow on Shatsky Rise (western Pacific Ocean) 石英中的氧同位素记录了沙斯基隆起（西太平洋）的古热流

IF 5.8 1区地球科学

Geology Pub Date : 2025-09-08 DOI: 10.1130/g53296.1

Oskar Schramm, Patrick J. Frings, Tommaso di Rocco, Andreas Pack, Michael Tatzel

{"title":"Oxygen isotopes in cherts record paleo−heat flow on Shatsky Rise (western Pacific Ocean)","authors":"Oskar Schramm, Patrick J. Frings, Tommaso di Rocco, Andreas Pack, Michael Tatzel","doi":"10.1130/g53296.1","DOIUrl":"https://doi.org/10.1130/g53296.1","url":null,"abstract":"Sedimentary cherts form from amorphous silica precursors that progressively crystallize into opal-CT and quartz during burial diagenesis. Recent studies have shown that the transformation kinetics of the silica polymorphs strongly depend on the prograde thermal history, suggesting a key role of basal heat flow in setting the 18O/16O and 17O/16O 18O/16O oxygen isotope ratios in chert (δ18Ochert, Δ′17Ochert). To investigate the relationship between paleo−heat flow and chert oxygen isotopes, we used Cretaceous to Neogene cherts that formed in the large igneous province Shatsky Rise in the western Pacific Ocean and a compilation of marine chert oxygen isotope ratios from previous studies. Using a reaction-advection-diffusion model, we demonstrate that the relationship between δ18Ochert, Δ′17Ochert, and the age of the underlying crust results from declining heat flow through sediment as the oceanic crust cools. Our reconstruction of heat flow at Shatsky Rise aligns with established geothermal background values. We propose that the Archean chert record indicates a diagenetic environment dominated by high heat flow that transitioned on billion-year time scales toward conditions resembling modern diagenesis.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"35 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145017899","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

Archean geodynamics and plate tectonics linked to Pb isotope variability 太古宙地球动力学和板块构造与铅同位素变异有关

IF 5.8 1区地球科学

Geology Pub Date : 2025-09-08 DOI: 10.1130/g53553.1

Sheree E. Armistead, Bruce M. Eglington, Sally J. Pehrsson, David L. Huston

引用次数: 0

Melting of eclogitic oceanic crust for the low-velocity zone within Earth’s upper asthenosphere 地球上层软流圈内低速带的榴辉岩海洋地壳融化

IF 5.8 1区地球科学

Geology Pub Date : 2025-09-05 DOI: 10.1130/g53540.1

Zongqi Zou, Yi-Gang Xu, Zaicong Wang, Yu Wang, Ming Li, Meiling Wang, Yutian Lei

引用次数: 0

New constraints on phosphate concentration and temperature in shallow late Tonian seawater 晚托尼亚浅层海水中磷酸盐浓度和温度的新约束

IF 5.8 1区地球科学

Geology Pub Date : 2025-09-05 DOI: 10.1130/g53532.1

Elizabeth J. Trower, Miquela Ingalls, James R. Gutoski, Virginia T. Wala

{"title":"New constraints on phosphate concentration and temperature in shallow late Tonian seawater","authors":"Elizabeth J. Trower, Miquela Ingalls, James R. Gutoski, Virginia T. Wala","doi":"10.1130/g53532.1","DOIUrl":"https://doi.org/10.1130/g53532.1","url":null,"abstract":"Although it is difficult to reconstruct Earth surface temperatures during Neoproterozoic time, sedimentological and paleomagnetic evidence demonstrate a dynamic climate, featuring two global “Snowball Earth” glaciations. The recent observation of petrographic fingerprints of ikaite, a mineral that typically forms in near-freezing sedimentary environments, in late Tonian strata was interpreted as evidence that low-latitude shallow marine environments were cold millions of years prior to the Cryogenian Period. Meanwhile, other recent work has demonstrated that elevated phosphate concentration ([DIP]) can inhibit calcite nucleation (perhaps enabling ikaite to form and persist at warmer temperatures) and that late Tonian carbonates formed in phosphate-rich seawater. So, was late Tonian seawater cold, or was it phosphate-rich? To address this question, we combined measurements of carbonate-associated phosphate and ooid-size-based pH constraints to reconstruct seawater [DIP] values for one snapshot of time in the late Tonian Period. Our seawater [DIP] estimates range from 3.8 µM to 7.8 µM, substantially elevated relative to modern shallow seawater and consistent with inferences from previous approaches. Our estimates are below values at which calcite nucleation inhibition has been observed, suggesting that elevated phosphate is an insufficient explanation for the ikaite forming in warm conditions and supporting the hypothesis that late Tonian climate was cool.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"33 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145003073","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

Long-term and multi-stage ice accumulation in the martian mid-latitudes during the Amazonian 亚马逊时期火星中纬度地区长期和多阶段的冰积累

IF 5.8 1区地球科学

Geology Pub Date : 2025-09-02 DOI: 10.1130/g53418.1

Trishit Ruj, Hanaya Okuda, Goro Komatsu, Hitoshi Hasegawa, James W. Head, Tomohiro Usui, Shun Mihira, Makito Kobayashi

引用次数: 0

Evaluating the resolving power of apatite 4He/3He thermochronology: Insights from the Fish Canyon Tuff 评价磷灰石4He/3He热年代学的分辨能力：来自鱼谷凝灰岩的启示

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-29 DOI: 10.1130/g53000.1

Cody L. Colleps, Peter van der Beek, Julien Amalberti, Edward R. Sobel, Marissa M. Tremblay, Maxime Bernard

{"title":"Evaluating the resolving power of apatite 4He/3He thermochronology: Insights from the Fish Canyon Tuff","authors":"Cody L. Colleps, Peter van der Beek, Julien Amalberti, Edward R. Sobel, Marissa M. Tremblay, Maxime Bernard","doi":"10.1130/g53000.1","DOIUrl":"https://doi.org/10.1130/g53000.1","url":null,"abstract":"Apatite 4He/3He thermochronology has the potential to provide high-resolution low-temperature thermal histories that bring valuable insight into near-surface crustal processes. However, this system has yet to be directly evaluated using single-grain 4He/3He analyses from a natural sample with an established thermal history. We present apatite 4He/3He spectra from the widely used Fish Canyon Tuff (FCT) age standard (San Juan volcanic field, southern Colorado, USA), collected at two localities with contrasting thermal histories: (1) a distal locality (FCT-D) where the early Oligocene eruptive age of the FCT is preserved in the apatite (U-Th)/He (AHe) system and the thermal history is well established; and (2) the classic FCT sampling locality (FCT-C) with younger, Early Miocene AHe dates and an unconstrained posteruptive thermal history. FCT-D apatite shows 4He/3He spectra indicative of no diffusive loss, with relative edge depletion of 4He induced by alpha ejection only, corroborating rapid eruptive cooling. In contrast, FCT-C apatite revealed notably diffusive 4He/3He spectra. Thermal-history inversions highlight the resolving power of apatite 4He/3He thermochronology, demonstrating its ability to (1) independently resolve rapid eruptive cooling at the FCT-D site, and (2) improve the resolution of postemplacement reheating and Early Miocene cooling at the FCT-C site. Refined FCT-C thermal histories reveal a distinctive onset of moderate cooling at ca. 20−19 Ma, likely reflecting footwall topographic development coinciding with regional Rio Grande rifting. This collective assessment of 4He/3He systematics further verifies its ability to substantially improve thermal history resolution, which is crucial to elucidating mechanisms driving crustal cooling.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"10 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144919587","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

Unique leaf mimicry in Jurassic insects 侏罗纪昆虫独特的叶片拟态

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-28 DOI: 10.1130/g53399.1

Yanzhe Fu, Chong Dong, Dolev Fabrikant, Chenyang Cai, Carolin Haug, Joachim T. Haug, Diying Huang

{"title":"Unique leaf mimicry in Jurassic insects","authors":"Yanzhe Fu, Chong Dong, Dolev Fabrikant, Chenyang Cai, Carolin Haug, Joachim T. Haug, Diying Huang","doi":"10.1130/g53399.1","DOIUrl":"https://doi.org/10.1130/g53399.1","url":null,"abstract":"Animals have evolved diverse defensive strategies under selective pressures, with mimicry being a crucial survival strategy for insects. Leaf mimicry is widespread in modern ecosystems, yet its fossil record remains sparse, often lacking direct evidence of target plant or clear morphological adaptations. We report three novel cases of leaf mimicry in Jurassic orthopterans (grasshoppers and crickets, including katydids) (Prophalangopsidae) from the Daohugou biota (ca. 163.5 Ma, northeastern China), in which the forewings exhibit highly specialized contrasting color patterns that closely resemble the abundantly co-occurring bennettitalean (extinct seed-bearing, cycad-like group) leaves. These cases provide the first unambiguous evidence in which both the mimicking insects and their plant models are preserved in the same bedding plane. It represents the first known instance of orthopteran mimicry in the Jurassic, fills a gap in the fossil record, and suggests that leaf mimicry has been a long-standing adaptive strategy in Orthoptera, independently evolving across different lineages throughout geological history. This finding highlights the dynamic interplay between plant community succession, predation pressures, and insect defensive strategies, expanding our understanding of the ecological significance and evolution of leaf mimicry in orthopterans.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"11 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144916093","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

Buoyancy of volatile-rich kimberlite melts, magma ascent, and xenolith transport 富含挥发物的金伯利岩融化、岩浆上升和捕虏体运输的浮力

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-21 DOI: 10.1130/g53387.1

Ana Anzulović, Anne H. Davis, Carmen Gaina, Razvan Caracas

引用次数: 0

Fe isotope decoding of fluid-absent versus fluid-present melting of deeply subducted continental crust 深俯冲大陆地壳无流体与有流体熔融的铁同位素解码

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-21 DOI: 10.1130/g52997.1

Er-Lin Zhu, Qiong-Xia Xia, Yi-Xiang Chen, Ren-Xu Chen, Hao-Hong Shu, Zhao-Ya Li, Yong-Fei Zheng

{"title":"Fe isotope decoding of fluid-absent versus fluid-present melting of deeply subducted continental crust","authors":"Er-Lin Zhu, Qiong-Xia Xia, Yi-Xiang Chen, Ren-Xu Chen, Hao-Hong Shu, Zhao-Ya Li, Yong-Fei Zheng","doi":"10.1130/g52997.1","DOIUrl":"https://doi.org/10.1130/g52997.1","url":null,"abstract":"Fluid-present melting and fluid-absent melting are two primary mechanisms for the chemical differentiation of continental crust. However, it is still challenging to decode these processes with conventional geochemical methods. In this study, we present systematic Fe isotope data of anatectic migmatites and gneisses from the Dabie orogen, China, which were formed by different mechanisms of crustal anatexis. Fluid-present melting of biotite generates migmatites with restricted Fe3+/ΣFe (0.31−0.44) and homogeneous δ56Fe values (0.06‰−0.17‰). In contrast, fluid-absent melting of phengite produces migmatites and migmatitic gneisses with dramatic Fe3+/ΣFe (0.26−0.94) and δ56Fe (0.04‰−0.61‰) variations. Quantitative modeling of Fe distribution during partial melting reveals that Fe isotope fractionation is governed by source mineral assemblages under varying melting regimes. During fluid-absent melting, the reactant phengite has much higher Fe3+/ΣFe and δ56Fe values than the peritectic biotite, resulting in high and heterogeneous δ56Fe values in the complementary melt. In contrast, during fluid-present melting, the reactant biotite and peritectic amphibole have similarly low Fe3+/ΣFe and δ56Fe values, leading to low and homogeneous δ56Fe values in the complementary melt. This establishes Fe isotopes as a novel tracer for crustal anatexis, critical for understanding continental reworking and intracrustal differentiation.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"27 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144900811","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

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