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Scree conglomerate and its derivatives in the Upper Cretaceous Kallankurichchi Limestone,Ariyalur Group,Cauvery Basin,South India

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Journal of Palaeogeography 2024年第3期13卷 495-508页

作者： Shilpa Srimani department of geological sciences Jadavpur UniversityKolkata700032India

The repetitive influx of coarse clastics of mixed composition,siliciclastics and carbonates,locally common in the lower part of the Upper Cretaceous marine Kallankurichchi Limestone specifies a resurgence of tectonic unrest in the Cauvery rift basin,*** basin-margin scree and its derivatives elicit diverse modes of emplacement and differ in many ways from denoting it only as basal *** study meticulously reveals the depositional history of these basin-margin coarse *** scree conglomerate bodies are wedge-shaped in appearance and often have flat,eroded *** places,their surfaces,tops and flanks,are encrusted with Inoceramus although internally,they are mostly *** are clast-supported and extremely poorly sorted,having interstitial spaces filled by sand-sized grains at the basal *** clasts can be traced into the underlying Sillakuddi Sandstone and the granitic *** clasts derived from the sandstone are angular and measure up to 60 cm in length,while the basement-derived clasts dominate the smaller(maximum diameter measured 5 cm)and more rounded *** elongated clasts are chaotically arranged,even oriented sub-vertically,reclining on other *** lowermost scree conglomerate has a sharp base,and the pebbles sunk into the underlying sandstone,although no discernible impact laminae wrapping their bottom were ever ***,the scree fans were initiated under the sea,which permitted the slow sinking of assorted rock fragments dropped from *** sporadic occurrence of marine fossils further corroborates this *** scree conglomerates at different stratigraphic levels transitioned laterally into conglomerates of mass flow origin and then to massive calcarenite,together forming wedge-shaped *** initial alignment of clasts parallel to bedding transforms to a chaotic alignment representing the transition from internally sheared flow to debris flow and associated ***

关键词： Scree conglomerate Kallankurichchi Limestone Tectonic subsidence Flow transformation Cauvery Basin

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Substrate control in track registration and preservation:insights across the Triassic—Jurassic boundary in southern Africa

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Journal of Palaeogeography 2024年第2期13卷 351-371页

作者： Loyce Mpangala Miengah Abrahams Emese M.Bordy department of geological sciences University of Cape TownCape TownSouth Africa

Tracks registration is influenced by the dynamic interplay between the pedal anatomy of the trackmaker,its behaviour,and the substrate conditions it interacts *** in substrate conditions,especially those linked to grain size and moisture content,often result in the most dramatic variations in track *** the upper Stormberg Group,main Karoo Basin of southern Africa,diverse trace fossils,primarily comprising Late Triassic—Early Jurassic dinosaur tracks,are *** studies have extensively documented individual ichnosites,investigating variations between sites over time,with recent studies suggesting that track abundance and anatomical fidelity increase *** the well-established link between substrate and track morphology,past studies have not specifically focused on substrate conditions,often emphasizing macro-sedimentary features ***,we examine the micro-sedimentary features of track-bearing units in the upper Stormberg Group using petrographic techniques to better understand the palaeosubstrate and its effect on fossil track registration and *** analysis revealed that very fine-grained sandstones and substrates modified by microbial activity tend to preserve tracks with greater abundance and/or higher anatomical ***,the prevalence of very fine-grained and microbially modified strata,and their associated track trends increases in younger stratigraphic *** the Triassic—Jurassic boundary in southern Africa,a boom in dinosaur track abundances is observed and credited to the proliferation of dinosaur populations during the Early *** findings,however,suggest that the observed local increase in track abundance(and anatomical fidelity)up-stratigraphy may be linked to substrate composition differences,which were ultimately controlled by large-scale changes in the palaeoenvironment from high-energy meandering fluvial to lower-energy aeolian-lacustrine settings in the L

关键词： Dinosaur tracks Footprint anatomical fidelity Micro-sedimentary features Substrate conditions Track registration Palaeoenvironmental context

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Triassic integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

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Science China Earth sciences 2024年第4期67卷 1152-1194页

作者： Guichun WU Zhansheng JI Gary GLASH Qinggao ZENG Jianxin YAO Key Laboratory of Stratigraphy and Palaeontology Ministry of Natural ResourcesInstitute of GeologyChinese Academy of Geological SciencesBeijing 100037China SinoProbe Laboratory Chinese Academy of Geological SciencesBeijing 100094China department of Geology and Environmental sciences State University of New York-FredoniaFredoniaNY 14063USA Xizang Autonomous Region geological and Mineral Exploration and Development Burea Lhasa 850010China

Rocks of the Qinghai-Tibetan Plateau(QTP)host abundant Triassic *** far,the well established marine fossil sequences based on ammonoids,conodonts,bivalves,brachiopods,radiolarians,and terrestrial spora-pollen sequence have become standard for biostratigraphic correlation of the *** much of Triassic time,the QTP occupied a marine setting as suggested by the dominance of marine *** main sedimentary types represented in the Triassic successions include littoral to shallow marine clastic rocks,shallow marine carbonate platform carbonates,bathyal to abyssal slope carbonates intercalated with clastic and siliceous deposits,coal-bearing clastic strata contained within paralic facies deposits,and littoral and terrestrial volcaniclastic *** deposits are organized into four stages in ascending order:(1)Early Triassic deposits that record marine transgression,including extensive shallow marine carbonate platform strata.(2)Middle Triassic Ladinian to Late Triassic Carnian deposits,including thin-bedded limestone,fine clastics,and siliceous rocks,that accumulated at greater depths than underlying Early Triassic strata and reflect the peak of the *** activity appears to have occurred in some areas during this stage.(3)Late Triassic Norian deposits that record the onset of marine regression as suggested by the widespread occurrence of platform *** is noteworthy that stage 3 deposits of the Qin-Qi-Kun area in the northernmost region of the QPT is dominated by terrestrial strata and displays evidence of local erosion.(4)Late Triassic Rhaetian littoral and shallow marine clastic and coal-bearing deposits that preserve the record of continued marine regression *** Indus-Yarlungzangbo Suture Zone(IYSZ)appears to have been the rifting axis during Triassic time as suggested by sedimentary facies trends that reflect deepening to south and ***,the Himalaya Block to the south of the IYSZ was part of the passive margin

关键词： Qinghai-Tibetan Plateau Triassic Biostratigraphy Lithostratigraphy Palaeobiogeography Sedimentary palaeogeography

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Environment Development and Health Safety System in Rural Areas of Bangladesh (Noakhali and Lakshmipur Districts)

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Journal of Environmental Protection 2024年第2期15卷 193-225页

作者： Asif Kader department of Environmental sciences and Management Jahangirnagar University Savar Bangladesh

At present time, Bangladesh is developing its position in all sectors of world prosperity. Economic development of Bangladesh depends on working ability of whole population of this country, although Bangladesh is not developed in health status of its whole population. A large percentage of people live in rural areas without any proper shelter. This study revealed the environmental development and health safety system in rural areas of Bangladesh, which is located in Noakhali and Lakshmipur districts of Bangladesh. Many sections were studied, which are the main structure of environmental development and health safety system of southeastern region of Bangladesh. The study found that there were three types of handicraft enterprises in the surveyed area such as handicraft input, like palm leaf, factories, Betel nut businesses, and Coconut businesses were headed and owned by the women and they were unaware of their health, environment and waste management or reduction of pollution. This study also reveals that microentrepreneurs did not ensure purified water supply and hygienic toilets within enterprises in the study area. The study also found that a significant portion of the microentrepreneurs are workers, and their family members were always fewer users of protective equipment during the COVID-19 pandemic. This study identified that most MEs faced transport or carrying facilities or big costing problems, including problems in available services for raw materials in the high category. In contrast, the high cost of transport facilities was very intensive in the study area. Moreover, it found that Microentrepreneurs (MEs) faced high product marketing costs for transport facilities, and a lack of proper pricing of the products in the study area. In addition, it explored that most of the microentrepreneurs did not receive sufficient credit support, and they faced negative attitudes and delayed responses from the credit services providers in the study area. It also found th

关键词： COVID-19 Handicraft Ingredients Microenterprise Environment Climate-Change Waste-Management

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Seasonal influence of freshwater discharge on spatio-temporal variations in primary productivity, sea surface temperature, and euphotic zone depth in the northern Bay of Bengal

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Acta Oceanologica Sinica 2024年第6期43卷 1-14页

作者： Hafez Ahmad Felix Jose Md.Simul Bhuyan Md.Nazrul Islam Padmanava Dash Geosystems Research Institute/department of Geosciences Mississippi State UniversityStarkville 39759USA department of Oceanography University of ChittagongChittagong 4331Bangladesh department of Marine&Earth sciences Florida Gulf Coast UniversityFort Myers 33965USA Bangladesh Oceanographic Research Institute Cox’s Bazar 4730Bangladesh Faculty of Marine sciences&Fisheries Institute of Marine SciencesUniversity of ChittagongChittagong 4331Bangladesh department of Geography and Environment Jahangirnagar UniversityDhaka 1342Bangladesh department of Geosciences Mississippi State UniversityStarkville 39759USA

Ocean productivity is the foundation of marine food web,which continuously removes atmospheric carbon dioxide and supports life at sea and on ***-temporal variability of net primary productivity(NPP),sea surface temperature(SST),sea surface salinity(SSS),mixed layer depth(MLD),and euphotic zone depth(EZD) in the northern B ay of Bengal(BoB) during three monsoon seasons were examined in this study based on remote sensing data for the period 2005 to *** compare the NPP distribution between the coastal zones and open BoB,the study area was divided into five zones(Z1-Z5).Results suggest that most productive zones Z2 and Zl are located at the head bay area and are directly influenced by freshwater discharge together with riverine sediment and nutrient *** Z1-Z5,the NPP ranges from 5 315.38 mg/(m^(2)·d) to 346.7 mg/(m^(2)·d)(carbon,since then the same).The highest monthly average NPP of 5 315.38 mg/(m^(2)·d) in February and 5 039.36 mg/(m^(2)·d) in June were observed from Z2,while the lowest monthly average of 346.72 mg/(m^(2)·d) was observed in March from Z4,which is an oceanic *** values vary from 6-154 m for the study area,and it has an inverse correlation with NPP *** is deeper during the summer season and shallower during the wintertime,with a corresponding increase in *** the year,monthly SST shows slight fluctuation for the entire study area,and statistical analysis shows a significant correlation among NPP,and EZD,overall positive between NPP and MLD,whereas no significant correlation among SSS,and SST for the northern ***-term trends in SST and productivity were significantly po sitive in head bay zones but negatively productive in the open *** findings in this study on the distribution of NPP,SST,SSS,MLD,and EZD and their seasonal variability in five different zones of BoB can be used to further improve the management of marine resources and overall environmental condition in response to clim

关键词： chlorophyll a sea surface temperature euphotic zone depth primary productivity Ganges-Brahmaputra ocean color Bay of Bengal monsoon

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Partitioning Anatolian Kinematics into Tectonic Escape and Slab Rollback Dominated Domains

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Journal of Earth Science 2024年第3期35卷 758-768页

作者： Jiannan Meng Timothy M.Kusky Erdin Bozkurt Hao Deng Ozan Sinoplu State Key Laboratory of geological Processes and Mineral Resources Center for Global TectonicsSchool of Earth SciencesChina University of GeosciencesWuhan 430074China Badong National Observatory and Research Station for Geohazards China University of GeosciencesWuhan 430074China department of geological Engineering Middle East Technical University06800 AnkaraTurkey department of Geosciences Auburn UniversityAuburn AL 36849USA

Anatolia is the global archetype of tectonic escape,as witnessed by the devastating 2023 Kahramanmaraş Earthquake sequence,and the 2020 Samos Earthquake,which show different kinematics related to the framework of the escape *** Positioning System(GPS)motions of the wedge-shaped plate differ regionally from northwestwards to southwestwards(from east to west).Anatolia was extruded westward from the Arabian-Eurasian collision along the North and East Anatolian fault systems,rotating counterclockwise into the oceanic free-faces of the Mediterranean and Aegean,with dramatic extension of western Anatolia in traditional ***,which is the dominant mechanism for this change in kinematics,extrusion related to the Arabia/Eurasia collision or rollback of the African slab beneath western Anatolia is still *** assess the dominant driving mechanisms across Anatolia,we analyze recent GPS velocity datasets,and decomposed them into N-S and E-W components,revealing that westward motion is essentially constant across the whole plate and consistent with the slip rates of the North and East Anatolia fault zones,while southward components increase dramatically in the transition area between central and western Anatolia,where a slab tear is *** phenomenon is related to different tectonic driving *** ArabiaEurasia collision drives the Anatolian Plate uniformly westwards while western Anatolia is progressively more affected by the southward retreating African subducting slab west of the Aegean/Cypriot slab tear,which significantly increases the southward component of the velocity field and causes the apparent curve of the whole modern velocity *** 2020 and 2023 earthquake focal mechanisms also confirm that the northward colliding Arabian Plate forced Anatolia to the west,and the retreating African slab is pulling the upper plate of western Anatolian apart in *** propose that the Anatolian Plate is moving westwards as

关键词： tectonics neotectonics tectonic escape slab rollback Anatolian Plate GPS velocity field geodynamics.

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An Overview on the Composition and Age of Upper Crust of Proto-Tethyan Lajishan Intra-oceanic Arc,NE Tibet Plateau

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Acta Geologica Sinica(English Edition) 2024年第2期98卷 285-302页

作者： FU Changlei HE Xiaohu YAN Zhen Jonathan CAITCHISON XIAO Wenjiao WANG Bingzhang LI Wufu LI Yusen SinoProbe Laboratory Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China Key Laboratory of the Northern Qinghai–Tibet Plateau geological Processes and Mineral Resources Qinghai Geological Survey InstituteXining 810012China department of Geology School of Earth SciencesYunnan UniversityKunming 650091China School of Earth and Environmental sciences University of QueenslandBrisbane 4072Australia Xinjiang Institute of Ecology and Geography Chinese Academy of SciencesUrumqi 830011China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China School of Earth Science and Resources China University of GeosciencesBeijing 100083China

Identification and anatomy of oceanic arcs within ancient orogenic belt are significant for better understanding the tectonic framework and closure process of paleo-ocean *** article summarizes the geological,geochemical,and geochronological characteristics of upper crust of Proto-Tethyan Lajishan intra-oceanic arc and provides new data to constrain the subduction evolution of the South Qilian *** intra-oceanic arc volcanic rocks,including intermediate-mafic lava,breccia,tuff,and minor felsic rocks,are distributed along southern part of the Lajishan ophiolite *** and isotopic compositions indicate that the intermediate-mafic lava were originated from depleted mantle contaminated by sediment melts or hydrous fluids,whereas the felsic rocks were likely generated by partial melting of juvenile mafic crust in intra-oceanic arc *** from felsic rocks yield consistent and concordant ages ranging from 506 to 523 Ma,suggesting these volcanic rocks represent the relicts of upper crust of the Cambrian intra-oceanic *** with the Cambrian forearc ophiolite and accretionary complex,we suggest that the Cambrian intra-oceanic arc in the Lajishan ophiolite belt is belonging to the intra-oceanic arc system which was generated by south-directed subduction in the South Qilian Ocean at a relatively short interval between approximately 530 and 480 Ma.

关键词： volcanic rocks intra-oceanic arc U-Pb age Lajishan ophiolite belt South Qilian Ocean Proto-Tethyan realm

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Investigation on the Deformation and Failure Patterns of Loess Cut Slope Based on the Unsaturated Triaxial Test in Yan'an,China

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Journal of Earth Science 2024年第1期35卷 235-247页

作者： Lina Ma Shengwen Qi Songfeng Guo Qiangbing Huang Xiaokun Hou Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China university of Chinese Academy of sciences Beijing 100049China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China department of geological Engineering Chang'an UniversityXi'an 710054China

The large-scale implementation of the Gully Stabilization and Land Reclamation(GSLR)project induces various failures of loess slopes due to excavation in Yan'an,***,the deformation and failure behavior of these excavated loess slopes have not been fully *** this study,field investigation was undertaken for analyzing the distributions and failure features of excavation-induced loess slope *** is found that plastic failure mainly occurs in Q_(3) loess layers and brittle failure in Q_(2).To understand the underlying failure mechanism,a series of triaxial shear tests were conducted on intact Q_(3) and Q_(2) loess samples that with different water contents,namely natural water content(natural),dry side of the natural value(drying 5%),and wet side(wetting 5%).The characteristics of stress-strain curves and failure modes of the samples were *** show that the stress-strain curves of Q_(2) samples are dominated by strain-softening characteristics,while Q_(3) samples mainly exhibit strain-harden features except in the drying ***,shear failures of Q_(3) specimens are mainly caused by shear crack planes(single,X or V-shaped).For Q_(2) loess,the dominance of tensile cracks is observed on the surface of damaged *** disclose the different failure modes of excavated slopes located in different strata,that is,the arc sliding failure of Q_(3) loess slopes and the stepped tensile failure of Q_(2) loess slopes,and are helpful in the design and management of the ongoing GSLR projects in the Loess Plateau.

关键词： loess slope slope stability failure patterns deformation

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Geochronology and Petrogenesis of Late Carboniferous to Early Permian Basalts in the Central Lhasa Subterrane, Southern Tibet: Implications for the Evolution of the Sumdo Paleo-Tethys Ocean

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Acta Geologica Sinica(English Edition) 2024年第4期98卷 955-968页

作者： MA Wang LIU Yingchao YANG Zhusen Jan-Marten HUIZENGA LI Zhenqing YUE Longlong ZHAO Sibo School of Earth sciences and Resources China University of GeosciencesBeijing 100083China Institute of Geology Sinoprobe LaboratoryChinese Academy of Geological SciencesBeijing 100037China MLR Key Laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing 100037China Faculty of Environmental sciences and Natural Resource Management Norwegian University of Life SciencesNO-1432ÅsNorway Economic Geology Research Centre(EGRU) College of Science and EngineeringJames Cook UniversityTownsvilleQueensland 4811Australia department of Geology University of JohannesburgAuckland Park 2006South Africa

Basalts from the Late Carboniferous to Early Permian are extensively developed in the central Lhasa subterrane, southern Tibet. Studying the petrogenesis of these rocks may have implications for the late Paleozoic arc magmatism along the central Lhasa subterrane uncovering more of the evolution of the Sumdo Paleo-Tethys Ocean and its dynamic mechanism. Basalt samples from the Luobadui Formation in the Leqingla area, NW of Linzhou City in the central Lhasa subterrane, southern Tibet exhibit arc-like geochemical signatures in a subduction-zone tectonic setting characterized by high Al_(2)O_(3) and low TiO_(2) contents, fractionated REE patterns with low Nb/La ratios and high LREE concentrations, and negative HFSE anomalies. Based on their higher Th/Ce, Nb/Zr, and lower Ba/Th, Pb/Nd ratios, slightly negative to positive ε_(Nd)(t) values, and the relatively high Sr-Pb isotopic compositions, these samples were probably derived from partial melting of a depleted mantle source of garnet + spinel lherzolite, metasomatized by subducted sediments around 297 Ma. Modeling of the trace elements indicates that these basalts experienced fractional crystallization of olivine, clinopyroxene and minor plagioclase during magma ascent and eruption. It is proposed that these Late Carboniferous–Early Permian basalts are associated with the northward subduction of the Sumdo Paleo-Tethys Ocean seafloor along the southern margin of the central Lhasa subterrane.

关键词： geochemistry northward subduction Sumdo Paleo-Tethys Ocean Lhasa terrane Tibet

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First SHRIMP zircon U-Pb dating constraints for the Ediacaran Wenghui Biota

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Journal of Earth Science 2024年

作者： Mingsheng Zhao Feng Tang Giovanni Mussini Yulan Li Heng Zhang Jianshu Chen Linzhi Gao department of Earth sciences university of Cambridge State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology CAS) 111 geological Brigade Guizhou Bureau of Geology and Mineral Resources College of Paleontology Shenyang Normal university Institute of Geology Chinese Academy of geological sciences Guizhou geological Survey

The Ediacaran period records a significant turning point in the evolution of life on Earth， witnessing the rise to ecological dominance of macroscopic tissue-grade organisms. The Wenghui biota from the Doushantuo Formation of South China hosts abundant multicellular algal macrofossils and problematica， some of which might be closely related to taxa from classic late Ediacaran assemblages from South Australia and the White Sea biota of Russia. However， a lack of well-resolved isotopic age estimates has hampered efforts to constrain the timing of appearance of the Wenghui biota， obfuscating its significance to our understanding of Ediacaran macroevolution in the aftermath of the Snowball Earth events. Here， we present the first SHRIMP zircon U-Pb dating results for samples obtained from a laminated tuff ash layer at the base of the Wenghui biota in the Doushantuo Formation， Jiangkou County， Tongren City， Guizhou Province， China. Our analyses yield an age of 595.4 ± 5.3 Ma for the first appearance of Wenghui biota， suggesting that its appearance postdated that of the Lantian- and Weng’an biotas， but preceded that of the Miaohe biota. These newly obtained age proxies offer an independent test of previous isotopic estimates for the age of the Wenghui biota， providing new chronostratigraphic evidence to map the succession of Ediacaran fossil assemblages on the Yangtze Platform during the Doushantuo interval. These data suggest that the Lantian， Weng’an， Wenghui， and Miaohe biotas may record a sequence of biotic assemblages attesting to successive phases in the radiation of Ediacaran macroscopic organisms， particularly macroalgae.

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