期刊文献+
共找到1,756篇文章
< 1 2 88 >
每页显示 20 50 100
Effects of Sowing Date and Sowing Rate on Yield of Rice Developed from Seedlings Dry-raised in Aperture Disk
1
作者 Shurong XIN Feixiang WANG +10 位作者 Wenfan BIAN xinyang LI Bin WU Jili WAN Yan SHI Linlin XU Hui MA Feng CHEN Bing GUO Yunjian SUN Zhuo XU 《Agricultural Biotechnology》 2024年第6期9-11,共3页
[Objectives]This study was conducted to find out the best sowing date and sowing rate of rice.[Methods]Based on the technique of dry seedling raising in aperture disk,the effects of sowing date and sowing rate on rice... [Objectives]This study was conducted to find out the best sowing date and sowing rate of rice.[Methods]Based on the technique of dry seedling raising in aperture disk,the effects of sowing date and sowing rate on rice yield were studied.[Results]Sowing date and sowing rate per hole had obvious effects on tillering dynamics,growth process,number of panicles per unit area,number of filled grains per panicle and yield of rice developed from dry-raised seedlings.The comprehensive analysis showed that the highest yield was 10285.5 kg/hm 2 with the sowing date of May 20 and sowing rate of 5 grains/hole.[Conclusions]This study provides theoretical support and data support for the popularization and application of rice developed from seedlings dry raised in aperture disk. 展开更多
关键词 RICE Dry seedling raising Sowing date Seeding rate YIELD
在线阅读 下载PDF
Eco-friendly nano-enabled fertilizers derived from date industry waste for sustainable and controlled-release of P,K and Mg nutrients:sorption mechanisms,controlled-release performance and kinetics
2
作者 Samira S.Elsabagh Elsayed A.Elkhatib Mohamed Rashad 《Bioresources and Bioprocessing》 2024年第1期28-42,共15页
Development of nano-enabled fertilizers from green waste is one of the effective options to enhance global agricultural productions and minimize environmental pollution.In this study,novel,eco-friendly and cost-effect... Development of nano-enabled fertilizers from green waste is one of the effective options to enhance global agricultural productions and minimize environmental pollution.In this study,novel,eco-friendly and cost-effective nano-enabled fertilizers(NEF)were synthesized using the planetary ball milling procedure.The NEF(nDPF1and nDPF2)were prepared by impregnation of nanostructured date palm pits(nDPP)with(KH2PO4+MgO)at 1:1 and 3:1(w/w)ratios respectively.The nDPP,nDPF1 and nDPF2 were extensively characterized.The produced nano-fertilizers enhanced soil water retention capacity with nDPF2 being the most effective.The water retention capacity of nDPF2 treated soil was 5.6 times higher than that of soil treated with conventional fertilizers.In addition,the nDPF2 exhibited superior sustained lower release rates of P,K and Mg nutrients for longer release periods in comparison with the conventional fertilizers.For instance,P cumulative release percentages from conventional fertilizers,nDPF1 and nDPF2 in soil reached 22.41%,10.82 and 8.9%respectively within 384 h.Findings from FTIR and XPS analyses suggested that hydrogen bonding and ligand exchange were the main interaction mechanisms of PO4-K-Mg ions with nDPP surface.The released kinetics data of the NEF revealed that power function was the best suitable model to describe the kinetics of P,K and Mg release data from NEF in water and soil.Pot study ascertained that the nano-enabled fertilizers(nDPF1 and nDPF2)significantly promoted biomass production and nutrient uptake of maize plants as compared to commercial fertilizer treated plants.The present work demonstrated the potential of NEF to increase nutrients uptake efficiency,mitigate moisture retention problem in arid soils and reduce nutrients loss through leaching and safeguard the environment. 展开更多
关键词 date palm pits Water retention Mechanisms of nutrients adsorption Controlled release Sustainable agriculture Nano-carrier Green byproducts
在线阅读 下载PDF
First discovery of Cretaceous tuffs in the Zhenyuan area,southwestern Ordos Basin,China:Constraints from zircon U-Pb dating
3
作者 Yin Chen Lu-lu Chen +1 位作者 Jian-guo Li Hua-lei Zhao 《China Geology》 2025年第2期457-459,I0048,I0053,共5页
1.Objective,The Cretaceous succession is characteristic of the aeolian sedimentary system in the Ordos Basin,which is the major ore-bearing layer for the sandstone-type uranium deposits.Based on the research of paleon... 1.Objective,The Cretaceous succession is characteristic of the aeolian sedimentary system in the Ordos Basin,which is the major ore-bearing layer for the sandstone-type uranium deposits.Based on the research of paleontology and magnetostratigraphy,formers believed it belonged to the Early Cretaceous(Huang YB,2010).However,the lack of intrusions or volcanic rocks for isotopic dating results in an unclear formation age for the Lower Cretaceous succession.Recently,tuffs were firstly discovered in the Luohandong Formation in the Zhenyuan area,Gansu Province,located in the southwestern Ordos Basin,China.The LA-ICP-MS zircon U-Pb dating of tuffs was carried out.The new ages can precisely constrain the depositional age of the Luohandong Formation and also provide significant indications for the study of regional volcanic activities,paleoclimate,basin evolution,and tectonic setting. 展开更多
关键词 southwestern ordos basin cretaceous tuffs cretaceous succession volcanic rocks aeolian sedimentary system la icp ms zircon u pb dating isotopic dating depositional age
在线阅读 下载PDF
Updating the Outdated
4
作者 QI YU 《China Today》 2025年第3期74-75,共2页
The ideology of being ready to make innovation and keeping abreast of the times is a defining feature of the Chinese civilization.IN several of his recent speeches President Xi Jinping stressed that the Chinese civili... The ideology of being ready to make innovation and keeping abreast of the times is a defining feature of the Chinese civilization.IN several of his recent speeches President Xi Jinping stressed that the Chinese civilization has the tradition of discarding the outdated in favor of the new and moving ahead with the times.In exploring a new philosophy that is suitable for governing China in the new era,China draws on its fine traditional culture to find ways of abolishing outdated ideas and making theoretical,practical,and institutional innovations,thus staying abreast of the time to create a better future. 展开更多
关键词 dated DATING CULTURE
在线阅读 下载PDF
Tracing carbonate diagenesis and hydrothermal activity during the opening of the Central South Atlantic: Insights from the Santos Basin (Brazil)
5
作者 Igor Figueiredo Cristiano Lana +5 位作者 Fernando F.Alkmim Marco A.Silva Maria Eugênia S.Souza Dorval C.Dias-Filho Eveline E.Zambonato Katia R.N.Mendonça 《Geoscience Frontiers》 2025年第5期245-259,共15页
The opening of the Central South Atlantic and the consequent formation of the eastern Brazilian continental margin was marked by a complex history of mafic magmatism,carbonate sedimentation,and deposition of a thick s... The opening of the Central South Atlantic and the consequent formation of the eastern Brazilian continental margin was marked by a complex history of mafic magmatism,carbonate sedimentation,and deposition of a thick salt layer.The carbonates underlying the salt layer(pre-salt carbonates)were formed in restricted lacustrine basins.Here,the timing and fluid sources of deposition,diagenetic,and hydrothermal alterations of the pre-salt carbonate rocks are defined through in-situ U-Pb dating,87Sr/86Sr,and trace element analyses of samples from the Santos Basin.The very alkaline nature of the Aptian lake(s)produced characteristically unique and widely distributed carbonate rocks such as Mg-clays with calcite spherulite and calcite crystal shrub limestones transitioning laterally and vertically into travertines formed by hydrothermal pulses during basin evolution.Hydrothermalism caused extensive replacement,dissolution,and calcite cementation.REE+Y PAAS-normalised patterns and 87Sr/86Sr ratios indicate that deposition/eo-diagenesis of the primary carbonates occurred in a lacustrine environment primarily controlled by evaporation,pH,and continental water source,with 2%–10%hydrothermal fluid input.Trace elements and Sr-isotope of travertines and burial diagenetic phases show that they are produced from a hot mixture of mafic/mantle-derived fluids and dissolution/alteration of older carbonate formations.U-Pb dating indicates that carbonate deposition occurred between 124.8±2.6 Ma and 120.0±1.6 Ma,earlier than previously proposed,followed closely by the circulation of hydrothermal fluids.Replacement and cementation ages range from 120.5±2.4 Ma to 80.4±2.4 Ma. 展开更多
关键词 PRE-SALT CARBONATE U-Pb dating Sr-isotope Trace elements LA-ICP-MS
在线阅读 下载PDF
Can a delayed sowing date improve the eating and cooking quality of mechanically transplanted rice in the Sichuan Basin,China?
6
作者 Yuxin He Fei Deng +13 位作者 Chi Zhang Qiuping Li Xiaofan Huang Chenyan He Xiaofeng Ai Yujie Yuan Li Wang Hong Cheng Tao Wang Youfeng Tao Wei Zhou Xiaolong Lei Yong Chen Wanjun Ren 《Journal of Integrative Agriculture》 2025年第9期3368-3383,共16页
Adjustment of the sowing date is a widely used measure in rice production for adapting to high-temperature conditions.However,the impact of a delayed sowing date(DS)on rice quality may vary by variety and ecological c... Adjustment of the sowing date is a widely used measure in rice production for adapting to high-temperature conditions.However,the impact of a delayed sowing date(DS)on rice quality may vary by variety and ecological conditions.In this study,we conducted experiments using four different sowing dates,the conventional sowing date 1(CS1),CS2(10 d later than CS1),DS1(30 d later than CS1),and DS2(30 d later than CS2),and three rice varieties,i.e.,Yixiangyou 2115,Fyou 498,and Chuanyou 6203.This experiment was conducted at four sites in the Sichuan Basin in 2018 and 2019 to evaluate the infuence of DS on the pasting properties of rice,which are a proxy for the eating and cooking quality(ECQ).In DS1 and DS2,the rice had a signifcantly greater amylose content(AC)but a lower protein content(PC),peak viscosity(PKV),cool paste viscosity(CPV),and hot paste viscosity(HPV)than in CS1 and CS2.Moreover,except for CS2 and DS1 in 2018,DS1 and DS2 led to 2.15-11.19%reductions in breakdown viscosity(BDV)and 23.46-108.47%increases in setback viscosity(SBV).However,the infuence of DS on rice pasting properties varied by study site and rice variety.In 2019,DS1 and DS2 led to BDV reductions of 2.35-9.33,2.61-8.61,10.03-17.78,and 2.06-8.93%,and SBV increases of 2.32-60.93,63.74-144.24,55.46-91.63,and-8.28-65.37%at the Dayi,Anzhou,Nanbu,and Shehong(except for SBV in CS2 and DS1)sites,respectively.DS resulted in greater reductions in PKV,HPV,CPV,and BDV and greater increases in the AC and SBV for Yixiangyou 2115 than for Chuanyou 6203 and Fyou 498.The correlation analysis indicated that PKV and HPV were signifcantly and positively related to the mean,maximum,and minimum temperatures after heading.These temperatures must be greater than 25.9,31.2,and 22.3℃,respectively,to increase the relative BDV and reduce the relative SBV of rice,thereby enhancing ECQ.In conclusion,DS might contribute to a signifcant deterioration in ECQ in machine-transplanted rice in the Sichuan Basin.A mean temperature above 25.9℃ after heading is required to improve the ECQ of rice. 展开更多
关键词 eating and cooking quality RICE sowing date pasting characteristics TEMPERATURE
在线阅读 下载PDF
Zircon U-Pb dating of metagabbro masses from the Liwu Group Complex within the Taka dome:Geochronological constraints on the Indosinian-Yanshanian tectonic events in western Sichuan,China
7
作者 Hong-chao Zhang Hong-bing Zhou +7 位作者 Bo Yan Chong-bo Sun Yue-zhong Wang Yun-chuan Zhao Yao Wen Ren-liang Cao Yang Qin Hong-qi Tan 《China Geology》 2025年第4期865-868,I0004-I0006,共7页
1.Objective The Songpan-Ganze terrane is a key region for understanding the tectonic evolution of the Tibetan Plateau and the Yangtze Craton.The Songpan-Ganzi complex comprises a thick succession of deformed Ladinian-... 1.Objective The Songpan-Ganze terrane is a key region for understanding the tectonic evolution of the Tibetan Plateau and the Yangtze Craton.The Songpan-Ganzi complex comprises a thick succession of deformed Ladinian-Norian turbidites(ca.230-203 Ma),covering about 200000 km^(2)of the eastern Tibet Plateau with a volume of approximately 2.0×10^(6)km^(3)(Fig.1a).Furthermore,this complex has over 100 Permian-Cenozoic felsic plutons. 展开更多
关键词 u pb dating INDOSINIAN zircon METAGABBRO taka dome YANSHANIAN liwu group complex tectonic events
在线阅读 下载PDF
Genetic interaction network of quantitative trait genes for heading date in rice
8
作者 Mengjiao Chen Yifeng Hong +6 位作者 Jiongjiong Fan Dengyi Cao Chong Yin Anjie Yu Jie Qiu Xuehui Huang Xin Wei 《Journal of Genetics and Genomics》 2025年第6期747-760,共14页
Several quantitative trait genes(QTGs)related to rice heading date,a key factor for crop development and yield,have been identified,along with complex interactions among genes.However,a comprehensive genetic interacti... Several quantitative trait genes(QTGs)related to rice heading date,a key factor for crop development and yield,have been identified,along with complex interactions among genes.However,a comprehensive genetic interaction network for these QTGs has not yet been established.In this study,we use 18K-rice lines to identify QTGs and their epistatic interactions affecting rice heading date.We identify 264 pairs of interacting quantitative trait loci(QTL)and construct a comprehensive genetic network of these QTL.On average,the epistatic effects of QTL pairs are estimated to be approximately 12.5%of additive effects of identified QTL.Importantly,epistasis varies among different alleles of several heading date genes.Additionally,57 pairs of interacting QTGs are also significant in their epistatic effects on 12 other agronomic traits.The identified QTL genetic interactions are further validated using near-isogenic lines,yeast two-hybrid,and split-luciferase complementation assays.Overall,this study provides a genetic network of rice heading date genes,which plays a crucial role in regulating rice heading date and influencing multiple related agronomic traits.This network serves as a foundation for understanding the genetic mechanisms of rice quantitative traits and for advancing rice molecular breeding. 展开更多
关键词 Genetic network EPISTASIS Epistatic effect Quantitative trait gene RICE Heading date
原文传递
Source-to-Sink Relationships between the Qaidam Basin and Its Surrounding Mountain Ranges:New Insights from Detrital Zircon U-Pb Ages in Modern River Sediments
9
作者 Xu Zhang Bowen Song +5 位作者 Tinglu Yang Yafei Hou Yibo Yang Keke Ai Jiaxuan Wang Kexin Zhang 《Journal of Earth Science》 2025年第3期930-946,共17页
The Cenozoic source-to-sink history of the Qaidam Basin is crucial for understanding of the basin-filling architecture,mountain-building processes and even the dynamics of the Tibetan Plateau growth.However,the proven... The Cenozoic source-to-sink history of the Qaidam Basin is crucial for understanding of the basin-filling architecture,mountain-building processes and even the dynamics of the Tibetan Plateau growth.However,the provenance history of Cenozoic strata in the Qaidam Basin remains ambiguous,especially in the northern Qaidam Basin.This controversy highlights the importance of obtaining the spatial source-to-sink relationships between the Qaidam Basin and its surrounding mountain ranges.In this study,we investigated the detrital zircon U-Pb ages of modern fluvial systems draining the East Kunlun Mountain.Their detrital zircon age distributions fall into five age groups:300-190,530-360,1000-560,2000-1100 and 2650-2000 Ma.The dominant age groups are 530-360 and 300-190 Ma,which represent the successive subduction of the Proto-Tethys and PaleoTethys Oceans and the subsequent continental collisions,respectively.Combining these new detrital zircon U-Pb ages with available age datasets,we finally obtained complete detrital zircon age information for modern fluvial systems in the whole Qaidam Basin.The U-Pb age distributions of modern river sands reveal that the zircon age signature of basement rocks in the East Kunlun Mountain is significantly different from that in the South Qilian Mountain but is similar to that in the Altyn Tagh Mountain.Moreover,these zircon age observations were confirmed by the significant difference in the Nd isotopic signature of modern river sands,which reveals a significant difference between the East Kunlun Mountain and South Qilian Mountain in the formation and evolution process. 展开更多
关键词 ZIRCON U-Pb dating modern river sand source-to-sink history Nd isotope Qaidam Basin TECTONICS
原文传递
Provenance evolution from subduction to arc-continent collision:An example from Zagros–Makran Transition Zone
10
作者 Parisa GholamiZadeh Bo Wan +2 位作者 Guido Meinhold Rasoul Esmaeili Mohammad Ebrahimi 《Geoscience Frontiers》 2025年第4期273-289,共17页
Arc-continent collision zones are critical areas where uplift,accretion,and erosion processes significantly influence the growth,elimination,or recycling of the continental crust.The Zagros–Makran Transition Zone,loc... Arc-continent collision zones are critical areas where uplift,accretion,and erosion processes significantly influence the growth,elimination,or recycling of the continental crust.The Zagros–Makran Transition Zone,located along the Minab-Zendan Fault,represents a convergence boundary between the Zagros continental domain and the Makran accretionary prism in southern Iran from the Cretaceous onwards.Several tectonic slices,including Neotethys ophiolitic remnants and the Ganj and Bajgan-Durkan complexes,have accreted along the southern margin of the Eurasian Plate during subduction in the western Makran wedge.To clarify the growth steps of the Makran Prism and the internal deformation associated with arc-continent collision,we used a provenance study of sandstones from the western Makran accretionary prism involving petrography of the main detrital components and U–Pb dating,Hf isotopic values,and trace elements of detrital zircon grains.Our findings reveal a progressive scenario in which oceanic arc-related rocks of the∼99 Ma Ganj Complex with Hf values ranging from+10 to+16 were uplifted during the Early to Late Eocene.The Eocene fore-arc sediments were sourced from the∼49–47 Ma Urumieh-Dokhtar Magmatic Arc with Hf values between−5 and+12,as well as from the Ganj Complex.The Jurassic–Cretaceous Bajgan-Durkan Complex was uplifted due to the Late Eocene to Oligocene collision of various terranes along the southern margin of the Eurasian Plate.This led to a major sediment influx into the Makran trench with a detrital signal in the range∼175–160 Ma with Hf isotopic values from−3 to+4 and alongside the Urumieh-Dokhtar Magmatic Arc with detrital ages ranging∼46–37 Ma and ca.80 Ma.Notably,metamorphic lithic grains began to appear in the sediments in the Late Eocene.The initial arrival of sediments from the Arabian margin to the arc-continent suture zone along the Minab-Zendan Fault indicates the onset of initial collision.During the Late Oligocene–Early Miocene,detrital zircon ages in the range of∼610–520 Ma,sourced from the Arabian basement,were deposited in the trench basin together with components from the Eocene Urumieh-Dokhtar Magmatic Arc and Cretaceous ophiolitic clasts of∼93 Ma with Hf isotopic values of+12 to+16.Following the development and uplift of the orogen from the Middle Miocene onward,detrital zircon grains from the Cretaceous–Miocene Urumieh-Dokhtar Magmatic Arc,Jurassic–Cretaceous Bajgan-Durkan Complex,and Cretaceous ophiolites are present in both the Makran and Zagros sedimentary domains. 展开更多
关键词 Makran prism Arc-continent collision PROVENANCE Detrital zircon U-Pb dating Minab-Zendan Fault
在线阅读 下载PDF
High-pressure Granulite-facies Metamorphism and Anatexis in Continental Collision Orogen:Evidence from the Mafic Granulite and Leucosomes in South Altun,Northwestern Qinghai-Tibet Plateau
11
作者 GUO Jing LI Yunshuai ZHANG Jianxin 《Acta Geologica Sinica(English Edition)》 2025年第1期53-68,共16页
Deciphering high-pressure granulite-facies metamorphism and anatexis within a collisional orogeny can provide crucial constraints on geodynamic evolution and melt activity during subduction and exhumation.Combining pe... Deciphering high-pressure granulite-facies metamorphism and anatexis within a collisional orogeny can provide crucial constraints on geodynamic evolution and melt activity during subduction and exhumation.Combining petrographic observations,mineral chemistry,REE in Grt-Cpx thermobarometry,and previous work,at least four stages are suggested for the metamorphic evolution of the mafic granulites in the South Altun,including the protolith stage,the high-pressure granulite-facies stage(909-1037℃and 17.3-30 kbar),medium-pressure granulite-facies overprint(9.1-11.9 kbar and 753-816℃),and subsequent late amphibolite-greenschist-facies metamorphism.Zircon U-Pb dating shows that the mafic granulites underwent high-pressure granulite-facies metamorphism at 497.2±3.7 Ma,while the leucosome formed at 498.2±2.9 Ma.Thus,the leucosomes from the host mafic granulite may have been formed at the high-pressure granulite-facies metamorphic event.The characteristics of zircon morphology,mineral inclusions,low Th/U values,HREE enrichment,and negative Eu anomalies indicate that these zircons from the leucosome were formed from the metamorphic melts.The characteristics of whole-rock major and trace elements as well as Hf isotopic features of zircons between the leucosomes and the host mafic granulite indicate that the melt may have been generated by the partial melting of the host mafic granulite. 展开更多
关键词 ANATEXIS zircon U-Pb dating HP mafic granulite leucosome South Altun
在线阅读 下载PDF
U-Pb Ages and Europium Anomalies of Detrital Zircon from Sediments in the West Kunlun Orogenic Belt:Implications for the Proto-Tethys Ocean Evolution
12
作者 Yinggang Zhang Xizhu Yao +4 位作者 Jin Wang Wenqing Pan Yongquan Chen Baoshou Zhang Tao Yang 《Journal of Earth Science》 2025年第3期947-959,共13页
The ocean crust remnants of the Proto-Tethys were preserved as the Kudi ophiolites in the West Kunlun Orogenic Belt(WKOB),and its evolutionary history was mainly constructed by research on igneous or metamorphic rocks... The ocean crust remnants of the Proto-Tethys were preserved as the Kudi ophiolites in the West Kunlun Orogenic Belt(WKOB),and its evolutionary history was mainly constructed by research on igneous or metamorphic rocks in the WKOB.Sedimentary rocks in the WKOB received little attention in the past;however,they could provide important constraints on the evolution of the oceanic lithosphere.Here,a series of shales and greywackes found in the Kudi area of WKOB were studied to constrain their deposition ages and explore their significance in the evolution of the ProtoTethys oceanic crust.The U-Pb dating and europium anomaly(Eu/Eu^(*))were analyzed for detrital zircons from greywackes interlayers,while bulk rare earth elements and yttrium(REY)of the shales were measured.Detrital zircons U-Pb ages yield a maximum deposition age of 436 Ma for the greywackes and black shales,while the REY distribution patterns of the black shales are similar to those of the Tarim Ordovician Saergan shales.Accordingly,the studied WKOB black shales were deposited in the Proto-Tethys Ocean during the Late Ordovician-Early Silurian period.The maximum deposition age at 436 Ma may represent a minimum closure time of the Proto-Tethys Ocean,which is also supported by the absence of increases in Eu/Eu^(*)values during the Late Ordovician-Early Silurian.Besides,our Eu/Eu^(*)values in detrital zircons indicate diminished orogenesis during the Archean to Meso-Proterozoic,subduction-related accretion at the margins of the supercontinent Rodinia during the Neoproterozoic. 展开更多
关键词 Proto-Tethys black shales West Kunlun Orogenic Belt detrital zircon europium anomaly U-Pb dating geochemistry TECTONICS
原文传递
Formation of late-stage passive-roof duplexes in fold-and-thrust belts:Thrusting sequence and thermochronologic constraints from the Northern Apennines(Italy)
13
作者 Marco Bonini Daniele Maestrelli +2 位作者 Domenico Montanari Federico Sani Maria Laura Balestrieri 《Geoscience Frontiers》 2025年第4期1-23,共23页
Passive-roof duplexes accommodate shortening at the mountain front of many fold-and-thrust belts worldwide.These structures typically manifest at the surface by hinterland-verging backthrusts that decouple thin-skinne... Passive-roof duplexes accommodate shortening at the mountain front of many fold-and-thrust belts worldwide.These structures typically manifest at the surface by hinterland-verging backthrusts that decouple thin-skinned thrust sheets from underlying foreland-verging duplexes.Although the main fac-tors controlling the development of passive-roof duplexes have mostly been identified,some of their intrinsic characteristics are still poorly defined.These relate to their spatio-temporal relationships to thrust faults located further inland in orogens,and their ability to transport younger rocks over older ones.This study explores these issues in the Casentino-Romagna axial sector of the Northern Apennines,which expose regional forethrusts and backthrusts.Detailed field mapping and analysis of superposed tectonic structures were integrated with apatite fission-track dating for constraining the tim-ing of rock exhumation and correlated tectonic events.Collectively,the results have allowed us to inter-pret the evolution of the study area in terms of two main deformation stages.Specifically,a first,long phase(D_(1))progressed from NE-directed,in-sequence thrusting(∼18 to∼10-9 Ma)to late out-of-sequence thrusting(∼8-5 Ma).A successive deformation phase,that we refer to as D_(2)(∼4-2 Ma),con-sisted of backthrusts and associated folds that were ubiquitous and systematically overprinted onto the foreland-verging D_(1)structures.Such retrovergent structures identify a late deformation phase dom-inated by the development of passive-roof duplexes that propagated hinterlandward into the orogen up to beyond the primary watershed ridge.Orogen-scale processes controlled the evolution of forelandward D_(1)-phase thrusts,although late erosion could have played a major role by bringing the Apennine thrust wedge toward an undercritical state.The latter conditions could have contributed to keeping the out-of-sequence thrusts active,and eventually promoted the development of the D_(2)passive-roof duplexes. 展开更多
关键词 Passive-roof duplexes Structural analysis Apatite fission-track dating Northern Apennines Critical wedge stability
在线阅读 下载PDF
Miocene Pb-Zn Mineralization in the Eastern Gangdese Metallogenic Belt:Evidence from in situ Rb-Sr Dating of Mica and Trace Element Geochemistry of Sphalerite
14
作者 ZHAO Xiaoyan YANG Zhusen +2 位作者 LIU Chang DONG Yanrui SHI Haiyan 《Acta Geologica Sinica(English Edition)》 2025年第3期806-821,共16页
Four Pb-Zn deposits,namely Bangpu(BP),Digei(DG),Nabuding(NB)and Cuoga(CG),are located within a 20 km distance of each other in the Gangdese porphyry copper belt(GPCB).The age and nature of the Pb-Zn mineralization,esp... Four Pb-Zn deposits,namely Bangpu(BP),Digei(DG),Nabuding(NB)and Cuoga(CG),are located within a 20 km distance of each other in the Gangdese porphyry copper belt(GPCB).The age and nature of the Pb-Zn mineralization,especially its relationship to magmatism,remain uncertain.In order to address this issue,mica from the four deposits was selected for in situ Rb-Sr dating,with sphalerite additionally being selected for in situ trace element analysis.Detailed geological research has revealed that the BP and NB deposits are primarily skarn-type Pb-Zn mineralization,while DG and CG are associated with magmatic hydrothermal breccia and are characterized by banded-type mineralization.The Rb-Sr isochron ages of syn-mineralization muscovite at the BP and CG deposits are 11±6 Ma and 19.7±0.7 Ma respectively.Fe,Cd,In,Mn and Sn occur as lattice substitutions in sphalerite from the four deposits.Cu exists as microinclusions in BP,but occurs isomorphically in the DG,NB and CG deposits.The formation temperatures of the four deposits,as calculated from sphalerite geothermometry,range from approximately 200℃to 300℃,indicating that they belong to medium temperature deposits.BP and NB are classified as skarn Pb-Zn deposits,while DG and CG are categorized as hydrothermal filled Pb-Zn deposits.These results suggest that,in addition to porphyry Cu mineralization,the GPCB also contains significant Miocene Pb-Zn mineralization. 展开更多
关键词 in situ Rb-Sr dating trace elements SPHALERITE Pb-Zn deposit Gangdese porphyry copper belt
在线阅读 下载PDF
Cosmogenic Nuclide Inheritance in Modern Moraines:A Case Study from the Hailuogou Glacier,Southeastern Tibetan Plateau
15
作者 ZHAO Dan ZHANG Zhigang +4 位作者 LI Yiman ZHANG Hongmei CHEN Luming SHANG Zhiyuan FU Ping 《Acta Geologica Sinica(English Edition)》 2025年第5期1455-1464,共10页
^(10)Be surface exposure dating is one of the methods most used in the dating of glacial landforms due to its well-understood dating mechanism,readily accessible materials.However,numerous dating studies have shown th... ^(10)Be surface exposure dating is one of the methods most used in the dating of glacial landforms due to its well-understood dating mechanism,readily accessible materials.However,numerous dating studies have shown that nuclide inheritance may overestimate the age as a result of the nuclide concentrations accumulating in glacial deposits prior to their eventual exposure.As the concentration is challenging to measure directly,it is typically assumed to be zero.This study investigated the potential nuclide inheritance in the Hailuogou Glacier by measuring^(10)Be concentrations in modern moraines.The results showed that(1)in the glacier foreland,the exposure ages of two sub-angular boulders aligned with the timing of glacier retreat suggested minimal or potentially negligible nuclide inheritance,whereas two amalgamated samples exhibited^(10)Be exposure ages of 820±278 yr and 570±168 yr,indicating that multiple cobbles may contain inherited nuclides;and(2)the exposure ages of the angular boulder samples from the modern glacier surface ranged from 366±151 yr to 221±85 yr,the coarse-grained(CG)sand samples ranged from 470±129 yr to 178±103 yr in age,and the ages of the amalgamated samples ranged from 1,114±197 yr to 97±37 yr,which may reflecting the upper limits of inherited ages. 展开更多
关键词 modern moraines nuclide inheritance ^(10)Be dating Hailuogou Glacier
在线阅读 下载PDF
Geodynamic record of Rodinia breakup to Gondwana formation:Insights from bulk geochemistry,whole-rock Sr-Nd isotopes,and zircon U-Pb-Hf data of Katherina Ring Complex,Sinai Peninsula,Egypt
16
作者 Mohamed Faisal Huan Li +6 位作者 Chao Sun Muhammad A.Gul Abdulgafar K.Amuda Wenbo Sun Jar Ullah Ibrahim H.Khalifa Sara Mustafa 《Geoscience Frontiers》 2025年第4期325-342,共18页
The Arabian-Nubian Shield(ANS)serves as a key geological archive,preserving the tectono-thermal evolution associated with the Rodinia breakup(∼900–800 Ma)and Gondwana formation(∼800–620 Ma).The Katherina Ring Comp... The Arabian-Nubian Shield(ANS)serves as a key geological archive,preserving the tectono-thermal evolution associated with the Rodinia breakup(∼900–800 Ma)and Gondwana formation(∼800–620 Ma).The Katherina Ring Complex(KRC),located in the Sinai Peninsula,Egypt(northern ANS),exemplifies continental growth through multistage magmatism and orogenesis,spanning the Tonian to Ediacaran periods(∼900–530 Ma).Despite its importance,debates persist regarding the nature,age,crustal characteristics,and magma source evolution of its constituent units.Situated in the northwestern part of the KRC,the Wadi Rofaiyed Cu deposit offers an exceptional natural laboratory for investigating continental crust formation during this interval,owing to its superb exposure and preservation.This study integrates detailed fieldwork,petrographic analyses,whole-rock geochemistry,Sr-Nd isotopes,and in situ zircon U-Pb-Lu-Hf isotopic data.It aims to(i)establish a robust chronological framework for the unmetamorphosed plutonic rocks of the KRC,(ii)advance the understanding of associated geodynamic processes,and(iii)elucidate the episodic magmatism events.The findings show that Wadi Rofaiyed juvenile crust developed in four main phases:(i)a subduction-accretionary phase(∼755 Ma)characterized by intense calc-alkaline magmatism,originating from the partial melting of mafic lower crust;(ii)a syn-collisional phase(∼630 Ma)occurred during the collision between the Saharan metacraton and the younger ANS crust,producing I-type granitoids formed through magma mixing and crustal anatexis;(iii)a post-collisional phase characterized by intermediate I-type(∼595 Ma)to felsic A-type alkaline magma(∼594 Ma),originated from the partial melting of the overthickened lower crust corresponding to lithospheric delamination;and(iv)an anorogenic phase(∼530 Ma)related to the final amalgamation of Greater Gondwana.Isotopic analyses across all four magmatic phases reveal low initial^(87)Sr/^(86)Sr(0.702648–0.703311)and positiveε_(Hf)(t)(+2.84 to+7.78)andε_(Nd)(t)(+2.61 to+5.21)values,consistent with lower crustal sources with depleted mantle-like signatures.The model ages(T_(DM2))for these magmatic rocks derived from zircon Hf(1.2–1.5 Ga)and whole-rock Nd isotopes(0.96–1.17 Ga)support a predominantly juvenile crustal origin.These findings underscore the multistage tectono-magmatic evolution of the northern ANS,advancing our understanding of obduction-accretion dynamics and crustal development during the Neoproterozoic. 展开更多
关键词 Arabian-Nubian Shield Egyptian Eastern Desert Katherina Ring Complex Neoproterozoic crustal evolution Sr-Nd isotopes Zircon U-Pb-Hf dating
在线阅读 下载PDF
A Deep Learning Approach to Classification of Diseases in Date Palm Leaves
17
作者 Sameera V Mohd Sagheer Orwel P V +2 位作者 P M Ameer Amal BaQais Shaeen Kalathil 《Computers, Materials & Continua》 2025年第7期1329-1349,共21页
The precise identification of date palm tree diseases is essential for maintaining agricultural productivity and promoting sustainable farming methods.Conventional approaches rely on visual examination by experts to d... The precise identification of date palm tree diseases is essential for maintaining agricultural productivity and promoting sustainable farming methods.Conventional approaches rely on visual examination by experts to detect infected palm leaves,which is time intensive and susceptible to mistakes.This study proposes an automated leaf classification system that uses deep learning algorithms to identify and categorize diseases in date palm tree leaves with high precision and dependability.The system leverages pretrained convolutional neural network architectures(InceptionV3,DenseNet,and MobileNet)to extract and examine leaf characteristics for classification purposes.A publicly accessible dataset comprising multiple classes of diseased and healthy date palm leaf samples was used for the training and assessment.Data augmentation techniques were implemented to enhance the dataset and improve model resilience.In addition,Synthetic Minority Oversampling Technique(SMOTE)was applied to address class imbalance and further improve the classification performance.The system was trained and evaluated using this dataset,and two of the models,DenseNet and MobileNet,achieved classification accuracies greater than 95%.MobileNetV2 emerged as the top-performing model among those assessed,achieving an overall accuracy of 96.99%and macro-average F1-score of 0.97.All nine categories of date palm leaf conditions were consistently and accurately identified,showing exceptional precision and dependability.Comparative experiments were conducted to assess the performance of the Convolutional Neural Network(CNN)architectures and demonstrate their potential for scalable and automated disease detection.This system has the potential to serve as a valuable agricultural tool for assisting in disease management and monitoring date palm cultivation. 展开更多
关键词 Deep learning convolutional neural networks date palm disease classification InceptionV3 DenseNet MobileNet precision agriculture smart farming sustainable agriculture disease monitoring
在线阅读 下载PDF
Multidisciplinary insights into the origin of natural gas from hydrocarbon generation and charging history of Permian dolomite reservoir in Sichuan Basin
18
作者 Yan-Xian Zhu Zhi-Liang He +5 位作者 Xiao-Wen Guo Long Li Kamaldeen O.L.Omosanya Jian Gao Ze Tao Xue-Song Lu 《Petroleum Science》 2025年第4期1428-1445,共18页
Understanding the origin of natural gas in deep and ultra-deep reservoirs with multiple potential source rocks remains challenging due to the complex thermal evolution of hydrocarbons at high temperatures and multi-st... Understanding the origin of natural gas in deep and ultra-deep reservoirs with multiple potential source rocks remains challenging due to the complex thermal evolution of hydrocarbons at high temperatures and multi-stage accumulation processes.This study investigates the origin of natural gas in deep hydrothermal dolomite reservoirs of the Maokou Formation,eastern Sichuan Basin,using hydrocarbon inclusion analysis,radiometric U-Pb dating of calcite cements,maturity modeling of potential source rocks,and constraints on reactivation periods of the nearby No.15 Fault System.Results indicate an oil charging event at approximately 246.9 Ma,followed by two episodes of gas charging at 222.4 Ma and 175.2 Ma.Furthermore,the oil and gas charging events occurred synchronously with activities of the No.15 Fault System,suggesting that its reactivation induced episodic hydrocarbon migration.Maturity modeling indicates that during the oil charging period,source rocks in the Qiongzhusi,WufengLongmaxi,and first member of the Maokou formations reached the stages of dry gas generation,significant oil generation,and the threshold of oil generation,respectively.During the subsequent twoepisode gas charging periods,the Qiongzhusi and Wufeng-Longmaxi formations progressed to dry and wet gas generation stages,respectively,while the first member of the Maokou Formation attained the oil generation stage.The hydrocarbon charging time and maturity history of potential source rocks indicate that:1)oil in hydrothermal dolomite reservoirs predominantly originated from the Wufeng-Longmaxi Formation at approximately 246.9 Ma;2)during the subsequent gas charging episodes,the WufengLongmaxi Formation could contribute wet gas,while the Qiongzhusi Formation likely supplied cracking gas from kerogen and residual liquid hydrocarbon;3)all oil in the hydrothermal dolomite reservoirs underwent thermal cracking to gas at approximately 110 Ma.This study indicates that gas pools in(ultra-)deep carbonate reservoirs of the Sichuan Basin have mixed genetic origins,with contributions from multiple sources.The multidisciplinary approach,combining direct dating of hydrocarbon charge events and simulation of hydrocarbon generation,proves robust and effective in identifying the origin of natural gas in(ultra-)deep reservoirs. 展开更多
关键词 U-Pb dating Hydrocarbon generation and charging HISTORY Origin of natural gas Deep and ultra-deep carbonate reservoirs Sichuan Basin
原文传递
Cloning of qHD8^(BAS),a Quantitative Trait Locus Regulating Heading Date in Rice
19
作者 ZHANG Zhengjiu BIAN Ying +3 位作者 YANG Ruoju ZHANG Xiaobo GONG Junyi FAN Jiongjiong 《Rice science》 2025年第3期283-286,I0005-I0011,共11页
Heading date is one of the most important agronomic traits that directly affect rice yield and determines the regional adaptability in specific growing environments.As a short-day plant,rice can grow under long-day(LD... Heading date is one of the most important agronomic traits that directly affect rice yield and determines the regional adaptability in specific growing environments.As a short-day plant,rice can grow under long-day(LD)conditions due to the synergistic regulation of many photosensitive genes.Using a set of chromosome segment substitution lines(CSSLs)with the indica cultivar Huanghuazhan(HHZ)as the recipient parent and Basmati Surkh 89-15(BAS)as the donor parent,we identified a QTL locus. 展开更多
关键词 chromosome segment substitution lines cssls agronomic traits identified qtl locus indica cultivar quantitative trait locus synergistic regulation many photosensitive genesusing heading date CLONING
在线阅读 下载PDF
AN AMS RADIOCARBON DATE FROM GRAVE BSII OF THE COPPER AGE CEMETERY OF REMEDELLO SOTTO (Brescia, Northern Italy)
20
作者 PAOLO BIAGI 《Natural Disaster Reduction in China》 1989年第1期299-300,共2页
A small sample of human bone from Tomb BSII of the Chalcolithic cemetery of RemedelloSotto (Brescia, Northern Italy) was processed with the AMS technique. It gave a date of 4070 ± 70BP (Beta-35224; ETH-6196) corr... A small sample of human bone from Tomb BSII of the Chalcolithic cemetery of RemedelloSotto (Brescia, Northern Italy) was processed with the AMS technique. It gave a date of 4070 ± 70BP (Beta-35224; ETH-6196) corresponding to 2711 (2609) 2512 cal BC yrs (1 sigma). Una datazione radiometrica per la Tomba BSII del cimitero Calcolitico di RemedelloSotto (Brescia). Viene presentata la datazione radiometrica eseguita con il metodo dell’acceleratore sudi un frammento di osso di calcagno del piede destro dello scheletro di inumato della Tomba BSII delsepolcreto di Remedello Sotto. L’analisi ha fornito il risultato di 4070 ± 70 BP (Beta-35224; ETH-6196)corrispondente a 2711 (2609) 2512 cal BC (1 sigma). 展开更多
关键词 AMS Northern Italy Brescia AN AMS RADIOCARBON date from GRAVE BSII OF THE COPPER AGE CEMETERY OF REMEDELLO SOTTO
原文传递
上一页 1 2 88 下一页 到第
使用帮助 返回顶部