Geology最新文献 - Book学术

Quantitative decoding of Ediacaran locomotory trace fossil morphologies: Evidence for the emergence of slender anterior-posterior body profiles 埃迪卡拉纪运动痕迹化石形态的定量解码：细长前后身体轮廓出现的证据

IF 5.8 1区地球科学

Geology Pub Date : 2025-06-09 DOI: 10.1130/g53332.1

Zekun Wang, Olmo Miguez-Salas

{"title":"Quantitative decoding of Ediacaran locomotory trace fossil morphologies: Evidence for the emergence of slender anterior-posterior body profiles","authors":"Zekun Wang, Olmo Miguez-Salas","doi":"10.1130/g53332.1","DOIUrl":"https://doi.org/10.1130/g53332.1","url":null,"abstract":"Trace fossils are vital for studying early animals and their co-evolution with paleoenvironments during the terminal Ediacaran, a period with sparse body fossil records. Thus, patterns of morphologic evolution are difficult to untangle for Ediacaran trace-makers and quantitatively unexplored. In this study, we use the integral scale, which reflects the distance within which a trajectory (i.e., force and displacement) is self-correlated, as a potential indicator for the characteristic length of trace-maker’s locomotion. By analyzing modern and fossilized animal-trace-correlated trajectories, a proportionality between the characteristic locomotory length and the trajectory integral scale is found. Since the length of the structure producing locomotion is no larger than that of the body, the characteristic locomotory length also reflects the minimal body length. Applying this scaling law to Ediacaran−Cambrian locomotory trace fossils (e.g., Archaeonassa, Gordia, Helminthopsis, Parapsammichnites), we identify clear evidence of slender anterior-posterior body axes after around 545 Ma, with gradually increasing minimal body length-to-width ratios to up to 4−12. The trace-makers probably had relatively rigid bodies with robust hydrostatic nerve-muscle systems enhancing directional sensation and movement, enabling them to thrive in dynamically complex, heterogeneous, and shifting habitats. These adaptations likely drove niche partitioning and cascading diversification, underpinning the evolutionary roots of the Cambrian Explosion and more familiar animals of the Phanerozoic. Our findings establish a novel quantitative approach to studying deep-time locomotory trace fossils, offering robust insights into early animal anatomy and paleoecological dynamics.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"10 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144252243","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

Evolution of a microfracture network induced by hydrocarbon generation during experimental maturation of organic-rich lacustrine shale 富有机质湖相页岩实验成熟过程生烃微裂缝网络演化

IF 5.8 1区地球科学

Geology Pub Date : 2025-06-09 DOI: 10.1130/g53458.1

Deyong Shao, Tongwei Zhang, Kitty L. Milliken, Shixin Zhou, Jing Li, Yanfang Li, Qin Zhou

{"title":"Evolution of a microfracture network induced by hydrocarbon generation during experimental maturation of organic-rich lacustrine shale","authors":"Deyong Shao, Tongwei Zhang, Kitty L. Milliken, Shixin Zhou, Jing Li, Yanfang Li, Qin Zhou","doi":"10.1130/g53458.1","DOIUrl":"https://doi.org/10.1130/g53458.1","url":null,"abstract":"Microfracture and matrix-pore networks evolve within organic-rich shales in response to thermal maturation. Here, we report observations on the Triassic Chang 7 Member black shale (total organic carbon [TOC] = 26.8 wt%; Ordos Basin in China) at varying stages of thermal maturation induced by miniature-core-plug gold-tube pyrolysis. Observations via scanning electron microscope and X-ray computed microtomography reveal that microfractures in the highly organic-rich shale are well developed throughout the entire oil-generation window; however, matrix pores are relatively underdeveloped. An abundance of bedding-parallel microfractures and especially lens-shaped microfractures are newly formed at EasyRo = 0.71%−0.91% (EasyRo—equivalent to vitrinite reflectance), whereas bedding-perpendicular microfractures appear only at EasyRo ≥1.14%, both as a consequence of fluid overpressure and mechanical disequilibrium compaction. Compaction is further recorded by morphological variation of Chrysophyceae cyst fossils in the shale upon thermal maturation. The microfracture geometries and abundant oil droplets trapped within the microfractures indicate these open microfractures may potentially serve as oil retention and storage space underground. The later development of bedding-perpendicular microfractures that cut across the bedding-parallel microfractures creates an interconnected three-dimensional fracture network and, therefore, facilitates significant hydrocarbon (HC) expulsion and/or transport via vertical migration from the generation zone. Our experimental findings improve the current understanding of HC primary migration and expulsion in organic-rich shales and suggest a possible new mechanism of shale oil retention and storage in thick high-TOC intervals and/or in overpressured basins. Moreover, our study sheds light on the dynamic process of fracturing that may accompany in situ underground conversion of medium- to low-maturity shale oil.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"586 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144252244","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

Coesite discovered in Australasian microtektites 在澳大拉西亚微晶岩中发现的钴矿

IF 5.8 1区地球科学

Geology Pub Date : 2025-06-03 DOI: 10.1130/g53151.1

L. Folco, E. Mugnaioli, M. Masotta, B.P. Glass

{"title":"Coesite discovered in Australasian microtektites","authors":"L. Folco, E. Mugnaioli, M. Masotta, B.P. Glass","doi":"10.1130/g53151.1","DOIUrl":"https://doi.org/10.1130/g53151.1","url":null,"abstract":"Microtektites are microscopic glass spherules produced by large impacts on Earth. Whether they formed as impact melt droplets or as condensates from a target-dominated vapor plume is debated. Combining optical, scanning, and transmission electron microscopy, we studied microscopic silica-rich inclusions in four Australasian microtektites to search for high-pressure phases produced by shock metamorphism in the precursor materials. Three microtektites are from deep-sea sediment cores close to the putative impact location in Southeast Asia, and one is from the Transantarctic Mountains at the extreme reaches of the strewn field. Inclusions in the oceanic microtektites consist of a few partially resorbed microscopic quartz and coesite grains set in a silica-rich glass matrix; the latter hosts a multitude of individual nanoscopic coesite relicts. The inclusion in the Antarctic microtektite consists of featureless silica-rich glass, is devoid of coesite, and shows diffusive boundaries. Coesite grains in the deep-sea microtektites are interpreted as impact-melted relicts of larger crystals originally formed during shock metamorphism in a quartz-rich target precursor. The presence of coesite in deep-sea microtektites strengthens the argument that Australasian microtektites found closest to the impact location originated as impact melt spherules upon compression-decompression melting during impact cratering and not as target vapor plume condensates. The high degree of digestion of the inclusion in the Antarctic microtektite is in line with the view that the most distal Australasian microtektites experienced the highest thermal regimes.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"9 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144229124","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

Escape of magma flow along the southern Central Asian Orogenic Belt prolonged the lifetime of the Tarim mantle plume 中亚造山带南部岩浆流的逸出延长了塔里木地幔柱的寿命

IF 5.8 1区地球科学

Geology Pub Date : 2025-06-02 DOI: 10.1130/g53464.1

Ke-Zhang Qin, Ben-Xun Su, Franco Pirajno, Richard E. Ernst, Hafida El Bilali, Ya-Jing Mao, Meng-Meng Cui, Jing Wang, Dong-Mei Tang

{"title":"Escape of magma flow along the southern Central Asian Orogenic Belt prolonged the lifetime of the Tarim mantle plume","authors":"Ke-Zhang Qin, Ben-Xun Su, Franco Pirajno, Richard E. Ernst, Hafida El Bilali, Ya-Jing Mao, Meng-Meng Cui, Jing Wang, Dong-Mei Tang","doi":"10.1130/g53464.1","DOIUrl":"https://doi.org/10.1130/g53464.1","url":null,"abstract":"When an ascending mantle plume arrives beneath a small craton and encounters ambient orogenic extension, what is likely to happen? We explored this scenario through considering the case of the Tarim mantle plume and the mafic-ultramafic intrusions in the southern Central Asian Orogenic Belt (CAOB). This mantle plume, which arrived beneath the Tarim craton, one of the smaller cratons on Earth, lasted from 300 Ma to 270 Ma with peaks at 290 Ma and 278 Ma. Synchronously, the CAOB was at the late orogenic extension stage with an eastward-propagating, scissor-like closure of the Paleo-Asian Ocean. Ni-Cu sulfide deposits hosted in mafic-ultramafic intrusions are typically associated with mantle plume events. However, an increasing number of Ni-Cu sulfide deposits are recognized as being emplaced in an associated orogenic setting, such as those associated with the southern CAOB. We observed that the number of mafic-ultramafic intrusions decreases with increasing distance from the Tarim craton (from the Tarim plume), and these intrusions show a 7−8-m.y. time lag in their emplacement ages (295−255 Ma, with peaks at 293 Ma, 282 Ma, and 271 Ma) with respect to the timing of Tarim large igneous province magmatism (300−270 Ma) within the Tarim craton. These unusual geochronological and tectonic links suggest that the plume materials were escaping to the northeast along an extensional belt in the southern CAOB, which is perpendicular to the inferred circular boundary of the plume, resulting in the formation of orogenic-style Ni-Cu sulfide deposits and a continuous magma supply from the deep mantle, prolonging the lifetime of the Tarim plume.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"5 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144228712","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

Dehydration of subducted slab gabbro in Lau Basin and its implications 陆盆地俯冲板状辉长岩脱水及其意义

IF 5.8 1区地球科学

Geology Pub Date : 2025-06-02 DOI: 10.1130/g52913.1

Shaowei Zhang, Alexandra Yang Yang, Siyu Zhao, Charles H. Langmuir, Taiping Zhao, Zexian Cui

引用次数: 0

The mechanical genesis of “fairy circle” depressions “仙女圈”萧条的机械成因

IF 5.8 1区地球科学

Geology Pub Date : 2025-05-30 DOI: 10.1130/g53384.1

Martin P.J. Schöpfer, Christine Detournay, Gabor Tari

引用次数: 0

Using dissolution surfaces in crystal clots to quantify pressure changes preceding the 2006 eruption of Augustine Volcano, Alaska 2006年阿拉斯加州奥古斯丁火山爆发前，利用晶体凝块的溶解表面来量化压力变化

IF 5.8 1区地球科学

Geology Pub Date : 2025-05-29 DOI: 10.1130/g52976.1

Valerie K. Wasser, Pavel E. Izbekov, Taryn M. Lopez, Nathan A. Graham, Jamshid A. Moshrefzadeh

{"title":"Using dissolution surfaces in crystal clots to quantify pressure changes preceding the 2006 eruption of Augustine Volcano, Alaska","authors":"Valerie K. Wasser, Pavel E. Izbekov, Taryn M. Lopez, Nathan A. Graham, Jamshid A. Moshrefzadeh","doi":"10.1130/g52976.1","DOIUrl":"https://doi.org/10.1130/g52976.1","url":null,"abstract":"Quantifying the buildup of pre-eruptive excess pressure in volcanic systems is crucial for the understanding of eruption-triggering mechanisms. The 2006 eruption of Augustine Volcano, Alaska, provides an excellent opportunity to investigate the response of the crystal cargo within a crystal-rich, intermediate host magma to temperature and pressure perturbations induced by mafic recharge shortly before the eruption. We use compositional changes of plagioclase together with adjoined and concurrently grown orthopyroxene to quantify these changes in magma conditions in response to this recharge event. We find ∼3.9 mol% anorthite increase in plagioclase is best explained by a 7.7 MPa (0.4−37 MPa, 80% uncertainty bounds) increase in magmatic pressure prior to the 2006 eruption. This value is close to the estimated tensile strength of rocks, suggesting that the pressure increase due to mafic recharge was likely sufficient to initiate dike intrusion and possibly trigger the eruption. This approach can be implemented broadly at crystal-rich, intermediate, and hydrous arc volcanoes, can provide independent estimates of pre-eruptive pressure changes to complement geophysical models, and can add new insights into the physical processes that lead to volcanic eruptions.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"176 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144228714","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

Basin-scale development of giant collapse structures induced by gypsum diagenesis 石膏成岩作用下巨型崩塌构造的盆地尺度发育

IF 5.8 1区地球科学

Geology Pub Date : 2025-05-29 DOI: 10.1130/g53338.1

Jimmy Moneron, Christopher Aiden-Lee Jackson

{"title":"Basin-scale development of giant collapse structures induced by gypsum diagenesis","authors":"Jimmy Moneron, Christopher Aiden-Lee Jackson","doi":"10.1130/g53338.1","DOIUrl":"https://doi.org/10.1130/g53338.1","url":null,"abstract":"Across buried sedimentary basins, the dissolution-prone nature of evaporite sequences drives the formation of collapse structures (e.g., sinkholes), fundamentally transforming landscapes at large scales. Understanding where, why, and how such structures form is crucial, given that they pose geological hazards that may threaten human safety and infrastructure stability or may affect subsurface resource extraction and geological storage. We use three-dimensional seismic reflection and borehole data from the Southern North Sea Basin to document giant (kilometers wide and several hundred meters deep) collapse structures within the Zechstein Supergroup (Permian) that developed at the basin scale (&gt;10,000 km2). Critically, these structures invariably overlie gypsum buildups capped by thick halite, with seismic-stratigraphic relationships enabling precise dating and facilitating accurate modeling. We propose that the transformation of gypsum to anhydrite during early burial initiated the extrusion of NaCl-undersaturated water, which provoked dissolution of the capping halite, leading to collapse at the depositional surface. The resulting landscape was buried and thus preserved by a potash infilling unit. To the best of our knowledge, neither the scale nor the genetic mechanism of these structures has previously been documented in the stratigraphic record.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"18 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144229128","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

Kilometers-scale subsidence of the inner Puerto Rico Trench wall since the Pleistocene 自更新世以来波多黎各海沟内壁的千米级下沉

IF 5.8 1区地球科学

Geology Pub Date : 2025-05-29 DOI: 10.1130/g53315.1

Uri ten Brink, Claudia Flores, Jason Chaytor, Marcie Purkey Phillips

{"title":"Kilometers-scale subsidence of the inner Puerto Rico Trench wall since the Pleistocene","authors":"Uri ten Brink, Claudia Flores, Jason Chaytor, Marcie Purkey Phillips","doi":"10.1130/g53315.1","DOIUrl":"https://doi.org/10.1130/g53315.1","url":null,"abstract":"We have observed a thin veneer of Pleistocene-age carbonate rocks on the southern side of Mona Block, a seamount northwest of Puerto Rico, above a water depth of 1800 m. Mona Block is located within the inner wall of the Puerto Rico Trench. A similar veneer of carbonate rocks (corals and pavement) was encountered during a deep submergence vehicle (DSV) Alvin dive in 1976 on the north side of Mona Block at depths of 3650−2900 m. We also observed a remnant Oligocene−Pliocene carbonate platform at a depth of 2080 m on the east side of the block. Restoring the carbonate outcrops to near sea level implies that Mona Block, with a summit currently at 670 m bsl, was an island with an elevation of ≥1000 m until the mid-Pleistocene and has subsided and tilted to the north thereafter. We suggest that the observed subsidence was caused by the foundering or retreating North American slab, which gave rise to the anomalously deep Puerto Rico Trench. Our estimated trench wall subsidence varies nonlinearly from ∼800 m in the distal part to ≥3700 m near the trench. Carbonate platform subsidence north of Puerto Rico is older (mid-Pliocene), suggesting that subsidence and, by inference, trench collapse had propagated westward with time. Mona Block is thus a yardstick for studying mantle processes associated with slab retreat and foundering.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"447 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144229129","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

Carbon conservation in continental subduction zones revealed by zinc isotopes in ultrahigh-pressure marbles 超高压大理岩中锌同位素揭示的大陆俯冲带碳守恒

IF 5.8 1区地球科学

Geology Pub Date : 2025-05-29 DOI: 10.1130/g53258.1

Wan-Yu Sun, Sheng-Ao Liu

{"title":"Carbon conservation in continental subduction zones revealed by zinc isotopes in ultrahigh-pressure marbles","authors":"Wan-Yu Sun, Sheng-Ao Liu","doi":"10.1130/g53258.1","DOIUrl":"https://doi.org/10.1130/g53258.1","url":null,"abstract":"Transfer of carbon from Earth’s surface into the interior via subduction regulates atmospheric CO2 concentrations over geologic time. The transfer efficiency of carbon in continental subduction zones, however, is less known than that in oceanic subduction zones. Zinc isotopes are a sensitive proxy of carbonate dissolution, with C-bearing fluids preferentially incorporating heavy zinc. We investigate zinc isotopes in ultrahigh-pressure marbles from the Dabie-Sulu orogenic belt formed via continental subduction. Coupled declines of zinc concentrations and isotope ratios in calcite marbles compared with their sedimentary protoliths provide direct evidence for dissolution, but the dissolution fraction of calcite carbonates, as a whole, is almost negligible. For dolomite marbles, the elevated zinc concentrations and decreased zinc isotope ratios indicate that dissolved carbonates underwent strong refixation within the slab. These findings collectively demonstrate that carbonates exhibit conservation behaviors during continental crust subduction and consequent exhumation. The vast majority (&gt;98%) of carbon in continental crust is ultimately stored in the exhumed slabs, indicating that the carbon budget in continental subduction systems is nearly balanced and has limited impact on the global carbon flux. Instead, oceanic subduction zones play an essential role in carbon transfer between Earth’s exterior and interior.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"39 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144229202","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