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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 {2. 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 {2. 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 {2. 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 2.19 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(2.19-2.2.)was estimated to be approximately 132. 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

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Circum-Indian Holocene sea-level database:A repository of distinct relative sea-level plots across the Indian Peninsula

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Journal of Palaeogeography 2024年第1期13卷 1-17页

作者： Shradha Menon Pankaj Khanna Santanu Banerjee REEFS Lab Department of Earth SciencesIIT GandhinagarPalajGandhinagarGujarat382355India department of earth {2. IIT BombayPowaiMumbai400076India

The Indian Peninsula is one of the most well-studied regions for Holocene sea-level fluctuations in the world, however, standardized relative sea-level datasets are missing. This study provides an archive of sealevel indicators(n = 162. 2. locations) along the western and the eastern sides of the peninsula, that have been used to develop Relative Sea Level(RSL) plots. Each dated sea-level indicator is recalibrated for its elevation based on tidal and tectonic correction, as well as age with reservoir correction, and have been separated into six zones based on coastal geomorphology and number of datasets. The database spans throughout the Holocene and covers sea-level depth/elevations from-45 m to +5 m from mean sea-level(MSL). Approximately 90 % of the dataset range from 8 ka to the present day. The first transgression is highly variable and identified between 8.5-8 ka BP in Gujarat(Zone 1), ~ 5.5 ka BP in Maharashtra(Zone 2., between 8 and 7 ka BP in Tamil Nadu(Zone 4) and between 8 and 7.5 ka BP in the Bengal coasts(Zone 6). No transgression above present sea-level is observed along Andhra Pradesh(Zone 5)(no data for Kerala-Zone 3).Further, Zones 1, 2. 4 and 6 show a strong uplift component(tectonic), whereas Zone 5 exhibits subsidence during the Holocene(Zone 3-insufficient data). Based on these findings, and given the region's coastal topography and tidal components, Zones 6 and 1 will likely undergo the largest coastal inundation, followed by Zones 5, 4, 2. and 3. These insights are critical in planning future coastal inundation measures across the Indian Peninsula.

关键词： Indian ocean Terraces Relative sea level curve Holocene Arabian sea Bay of Bengal

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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 {2. 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 2.14 to May 2.2.,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 2.0 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

Pumping-induced Well Hydraulics and Groundwater Budget in a Leaky Aquifer System with Vertical Heterogeneity in Aquitard Hydraulic Properties

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Acta Geologica Sinica(English Edition) 2024年第2期98卷 477-490页

作者： ZHUANG Chao LÜChenyang YAN Long LI Yabing ZHOU Zhifang WANG Jinguo DOU Zhi Walter A.ILLMAN School of earth sciences and Engineering Hohai UniversityNanjing 211100China School of Geography Earth and Environmental SciencesUniversity of BirminghamBirmingham B152TTU.K. department of Modern Mechanics University of Science and Technology of ChinaHefei 230027China department of earth and Environmental {2. University of WaterlooOntario N2L 3G1Canada

In groundwater hydrology,aquitard heterogeneity is often less considered compared to aquifers,despite its significant impact on groundwater hydraulics and groundwater resources evaluation.A semi-analytical solution is derived for pumping-induced well hydraulics and groundwater budget with consideration of vertical heterogeneity in aquitard hydraulic conductivity(K)and specific storage(S_(s)).The proposed new solution is innovative in its partitioning of the aquitard into multiple homogeneous sub-layers to enable consideration of various forms of vertically heterogeneous K or S_(s).Two scenarios of analytical investigations are explored:one is the presence of aquitard interlayers with distinct K or S_(s) values,a common field-scale occurrence;another is an exponentially depth-decaying aquitard S_(s),a regional-scale phenomenon supported by statistical *** investigations reveal that a low-K interlayer can significantly increase aquifer drawdown and enhance aquifer/aquitard depletion;a high-S_(s) interlayer can noticeably reduce aquifer drawdown and increase aquitard *** of low-K or high-S_(s) interlayers also significantly impact well hydraulics and groundwater *** the context of an exponentially depth-decaying aquitard S_(s),a larger decay exponent can enhance aquifer *** using current models with a vertically homogeneous aquitard,half the sum of the geometric and harmonic means of exponentially depth-decaying aquitard S_(s) should be used to calculate aquitard depletion and unconfined aquifer leakage.

关键词： hydrogeology aquitard vertical heterogeneity semi-analytical solution well hydraulics groundwater budget

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Water and other volatiles on Mars

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National Science Review 2024年第06期11卷 12-14页

作者： Sen Hu Yubing Gao Zhan Zhou Liang Gao Yangting Lin Key Laboratory of the earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of Sciences College of earth and Planetary sciences University of Chinese Academy of Sciences

Mars, the intriguing red planet, is one of the planets most similar to the earth in our solar system. It is widely accepted that Mars could have had a warm and wet climate in its early history supported by numerous lines of evidence, e.g. topography, canyons, outflow channels, presence of phyllosilicates and evaporative salts,sedimentary formation, and many others (e.g.[1]), and thus Mars is believed to once have a potentially habitable environment which could be able to supply fundamental conditions for the evolution of potential lives.

关键词： ISOTOPIC COMPOSITION MARTIAN ATMOSPHERE SUBSURFACE WATER ABUNDANCE TISSINT H2. CO2

Spatio-temporal variability in microfossil and geochemical records of Cenomanian-Turonian oceanic anoxic event-2. a review

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Journal of Palaeogeography 2024年第4期13卷 646-674页

作者： C.P.Sooraj Shweta Gupta Jahnavi Punekar department of earth {2. Indian Institute of Technology Bombay

The Cenomanian-Turonian boundary oceanic anoxic event(OAE-2. Bonarelli event; ～94 Ma) is associated with a species turnover in the marine calcareous microfossil record, widespread marine anoxia,black shale deposition and positive δ13C excursions. This study reviews 141 CTBE sites globally, aiming to understand micropaleontological, geochemical, and sedimentological expressions of OAE-2. There is a clear palaeogeographic and palaeobathymetric heterogeneity in the development of OAE-2.marine anoxia. A majority of the documented OAE-2.sites are from deep marine environments. The calcareous nannoplankton and benthic foraminifera record a diversity decline, while planktic foraminifera shows community level shifts and no major mass extinction. The variability of total organic carbon in OAE-2.sediments across sites(10 wt.%) and the δ13C profiles(diachronous) have been attributed to different mechanisms of anoxia *** increased primary “productivity model” gains support from productivity proxies(e.g., Ba, P, Cu, Ni),redox-sensitive elements(e.g., Mn, Mo, U, V, As), and eutrophic genera(e.g., benthic foraminifera Gabonita spp., calcareous nannofossils Biscutum spp. and Zeugrhabdotus erectus). The enhanced organic carbon“preservation model” in stratified(semi) restricted basins gains support from sites with lower enrichment of redox-sensitive elements and oligotrophic flora and fauna in the OAE-2.records. Geochronology of the Caribbean and the High Atlantic Large Igneous Province events(CLIP and HALIP) mark them as likely triggers of the OAE-2.related global perturbation of marine biogeochemistry. Volcanic triggers may have caused climate warming, altered hydrological cycles, enhanced continental weathering, shifts in ocean circulation, and nutrient flows. Addressing knowledge gaps, further research is urged, utilizing innovative proxies, and exploring underrepresented depositional systems to comprehensively understand OAE-2.onset and biotic crisis.

关键词： Oceanic anoxic Event-2 Global organic carbon distribution Geochemical proxies Marine calcifiers Palaeoceanography