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Global weirding at mass extinction horizons

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National Science Review 2024年第1期11卷 10-12页

作者： Gregory J.Retallack department of earth sciences University of Oregon

A strong motivation for studying mass extinctions is understanding how current climatic and biodiversity crises will affect creatures living on land such as ourselves. Perhaps the question is: how bad can it get? In that case, terrestrial Permian-Triassic mass extinctions are an irresistible worst-case scenario [1].

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Analysis of ancient mass extinction recoveries in marine environments: generating strategies for managing outcomes of the current mass extinction

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National Science Review 2024年第1期11卷 8-10页

作者： David J.Bottjer department of earth sciences University of Southern California

The defining feature of a mass extinction and its associated recovery is the global amount of extinction that occurred[1]. However, there is finer-scale detail to the story, as seen in the ongoing modern mass extinction(the sixth mass extinction), which exhibits variable effects among marine ecosystems and environments, and hence geographic areas [1].

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Late Ordovician Mass Extinction: earth, fire and ice

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National Science Review 2024年第1期11卷 51-65页

作者： David A.T.Harper Palaeoecosystems Group Department of Earth SciencesDurham University

The Late Ordovician Mass Extinction was the earliest of the ‘big’ five extinction events and the earliest to affect the trajectory of metazoan life. Two phases have been identified near the start of the Hirnantian period and in the middle. It was a massive taxonomic extinction, a weak phylogenetic extinction and a relatively benign ecological extinction. A rapid cooling, triggering a major ice age that reduced the temperature of surface waters, prompted a drop in sea level of some 100 m and introduced toxic bottom waters onto the shelves. These symptoms of more fundamental planetary processes have been associated with a range of factors with an underlying driver identified as volcanicity. Volcanic eruptions, and other products, may have extended back in time to at least the Sandbian and early Katian, suggesting the extinctions were more protracted and influential than hitherto documented.

关键词： Ordovician LOME paleoecology palaeobiogeography biotas

Identifying flow regime in the aquifer of fractured rock system in Germi Chai Basin,Iran

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Journal of Mountain Science 2024年第2期21卷 574-589页

作者： VAEZIHIR Abdorreza SEPEHRIPOUR Ali TABARMAYEH Mehri department of earth sciences University of TabrizTabriz ***Iran

Considering the importance of fractured rock aquifers in the hydrogeologic process,this research aimed to analyze the flow regime,internal degree of karstification,and estimate storage volume in fractured rock aquifers of the Germi Chai Basin in northwest Iran,which is attributed to its active tectonics,erosion,and the lithological *** the geological setting,the hypothesis is that this basin is characterized by a high degree of karstification and diffuse or intermediate flow regime leading to variation in discharge flow *** hydrodynamic and hadrochemical analysis was conducted on 9 well distributed springs across the basin from 2019 to *** maximum flow rate in most of the springs appeared in the early wet season despite their different levels of fluctuations on the monthly discharge time *** the spring recession curve form revealed an aquifer containing multiple micro-regimes withαrecession coefficients and a degree of karstification ranging between 0.001 to 0.06 and 0.55 to 2.61,*** findings indicated a dominant diffuse and intermediate flow system resulting from the development of a high density of fractures in this *** electrical conductivity of the spring changes inversely proportional to the change in flow discharge,indicating the reasonable hydrological response of the aquifer to rainfall *** analysis revealed that the delay time of spring discharge after rainfall events mostly varies between 10 to 30 *** total dynamic storage volume of the spring for a given period(2019-2020)was estimated to be approximately 1324 million cubic meters reflecting the long-term drainage potential and high perdurability of dynamic *** the maximum and minimum ratio revealed that the springs recharging system in Germi Chai Basin comes under the slow aquifers *** finding provides valuable insight into the hydrogeological properties of fractured rock aquifers contributing to effective w

关键词： Fractured rock aquifer Hydrodynamic and hadrochemical analysis Germi Chai Basin Recession coefficient

Effect of diagenetic processes and depositional facies on reservoir quality of the Eocene Carbonate Sequence(Sakesar Limestone) in the Central Salt Range， Pakistan

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Journal of earth Science 2024年

作者： Naveed Rehman Shu Jiang Syed Haroon Ali Asim Falak Naz Muhammad Tariq Key Laboratory of Tectonics and Petroleum Resources， Ministry of Education， China university of Geosciences department of earth sciences， university of sargodha

The effect of depositional facies and diagenesis on the reservoir potential of the Sakesar Limestone has been assessed through core plug porosity and permeability data， scanning electron microscope (SEM)， and petrographic study in three stratigraphic sections (Karuli， Badshah Pur， and Sardhai) of Central Salt Range. Field observations revealed three lithofacies: thin-bedded limestone with shale intercalation， thick-bedded nodular limestone， and highly fractured limestone. Based on a petrographic study， six microfacies have been identified: Bioclastic Mudstone Facies (SKF-1)， Lockhartia-Nummulitic Wackestone Facies (SKF-2)， Assilina-Alveolina Packstone Facies (SKF-3)， Lockhartia-Nummulitic Packstone Facies (SKF-4)， Alveolina Grainstone Facies (SKF-5)， and Nummulitic Grainstone Facies (SKF-6). The Sakesar Limestone shows various diagenetic changes such as compaction， dissolution， dolomitization， cementation， and fracturing， resulting in different types of pores. Two reservoir zones are identified in the Sakesar Limestone: a mud-dominated reservoir in an outer ramp setting with interparticle and micropores and a bioclastic grain-dominated facies in an inner ramp setting with intraskeletal and fracture porosity. The porosity and permeability of grain-dominated facies (8-30% and 0.8-8 mD) are higher than mud-dominated facies (4-15% and 0.5-4 mD) due to intraskeletal/intraparticle pores and dolomitization.

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Fossil organic carbon weathering:A nexus in global biogeochemical cycles

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Science China earth sciences 2024年第6期67卷 2068-2072页

作者： Gaojun LI Gen KLI department of earth and Planetary sciences Nanjing UniversityNanjing 210023China department of earth Science University of CaliforniaSanta Barbara CA 93106USA

The participation of life processes represents a fundamental feature of geochemical cycles on the planet *** of primary processes is that the carbon-based life utilizes photosynthesis to convert atmospheric CO_(2) int... 详细信息

关键词： weathering earth geochemical

Influence of upstream solar wind on magnetic field distribution in the Martian nightside ionosphere

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earth and Planetary Physics 2024年第5期8卷 728-741页

作者： JiaWei Gao ZhaoJin Rong Qi Zhang Anna Mittelholz Chi Zhang Yong Wei Key Laboratory of earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences College of earth and Planetary sciences University of Chinese Academy of Sciences Swedish Institute of Space Physics department of earth sciences Center for Space Physics and department of Astronomy Boston University

Using over eight years of Mars Atmosphere and Volatile Evolutio N （MAVEN） data,from November 2014 to May 2023,we have investigated the Martian nightside ionospheric magnetic field distribution under the influence of upstream solar wind drivers,including the interplanetary magnetic field intensity (∣BIMF∣),solar wind dynamic pressure （PSW）,solar extreme ultraviolet flux （EUV）,and Martian seasons （Ls）.Our analysis reveals pronounced correlations between magnetic field residuals and both∣BIMF∣and *** observed with EUV flux and Lswere weaker—notably,magnetic field residuals increased during periods of high EUV flux and at Mars *** find that the IMF penetrates to an altitude of 200 km under a wide range of upstream conditions,penetrating notably deeper under high∣BIMF∣*** analysis also indicates that EUV flux and IMF cone angle have minimal impact on IMF penetration *** findings provide useful constraints on the dynamic nature of Martian atmospheric escape processes and their evolution,suggesting that historical solar wind conditions may have facilitated deeper IMF penetration and higher rates of ionospheric escape than are observed ***,by establishing criteria for magnetic‘quiet’conditions,this study offers new insights into the planet’s magnetic environment under varying solar wind influences,knowledge that should help refine models of the Martian crustal magnetic field.

关键词： Martian magnetic field external magnetic field upstream solar wind drivers IMF penetration altitude magnetic field activity indices

Trend of ambient seismic noise attenuation tomography:Theory and applications

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Science China earth sciences 2024年第10期67卷 3326-3330页

作者： Xin LIU Zhanwen LI department of earth sciences University of Hong KongHong Kong 999077China

1. Introduction Ambient seismic noise is an approximately uniform wave field generated by persistent and high-energy noise sources such as earth's inherent vibrations and oceanic noise propagating within earth's interior and multiple scattering. This noise wave field is widely distributed in subsurface structure and carries information about mechanical and physicochemical property of fault fracture zones.

关键词： seismic earth fault

Petrologic evolution of the Gysian ophiolitic serpentinites,NW Iran

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Acta Geochimica 2024年第5期43卷 996-1011页

作者： Monir Modjarrad Donna L.Whitney Hadi Omrani department of Geology Faculty of SciencesUrmia UniversityUrmiaIran department of earth and Environmental sciences University of MinnesotaMinneapolisMNUSA department of Geology Faculty of SciencesGolestan UniversityGorgānIran

The Gysian ophiolite of NW Iran is located at the intersection of the ophiolite belts of SE Turkey,NE Iraq,and Iran,and provides the opportunity to investigate the preserved subduction and obduction history of an important tectonic site that has not previously been *** serpentinized peridotites of the Gysian ophiolite contain the assemblagelizardite+chrysotile+spinel/Mg-spinelwith relict clinopyroxene(diopside)and very rare relict orthopyroxene and *** compositions of clinopyroxenes and spinels are more consistent with the formation of the inferred protolithharzburgitesinafore-arcorsupra-subduction zone instead of an abyssal *** Gysian ophiolite is a remnant of the Neo-Tethyan arc-ophiolitic system and records shallow subduction(<50 km,indicated by the absence of antigorite)in the Late Cretaceous to Paleocene beforeobductionalongthrustfaultsoverthecontinental *** review the spatial trends of the metamorphic grade of the Neo-Tethyan ophiolites in this region and provide detailed information about the petrology and mineral chemistry of the Gysian ophiolite.

关键词： Ophiolite Neo-Tethyan Gysian Serpentinite Iran