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Earthquake focal mechanisms and stress field in Sichuan-Yunnan area determined using P wave polarity and short period P and S waveform data 被引量:1
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作者 陈天长 郑斯华 ZHENG Si-hua 《Acta Seismologica Sinica(English Edition)》 CSCD 2001年第4期466-470,共5页
关键词 Sichuan-Yunnan area focal mechanism stress field
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Seismic Hazard Assessment for Japan after the 2011 Tohoku-Oki Mega-Thrust Earthquake (Mw9.0)
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作者 Hiroyuki Fujiwara Nobuyuki Morikawa 《Journal of Civil Engineering and Architecture》 2012年第9期1117-1127,共11页
关键词 地震灾害评估 日本 推力 地震危险性评估 东北 地震后 OKI 强地面运动
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Retrieving chlorophyll content and equivalent water thickness of Moso bamboo(Phyllostachys pubescens) forests under Pantana phyllostachysae Chao-induced stress from Sentinel-2A/B images in a multiple LUTs-based PROSAIL framework 被引量:1
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作者 Zhanghua Xu Anqi He +10 位作者 Yiwei Zhang Zhenbang Hao Yifan Li Songyang Xiang Bin Li Lingyan Chen Hui Yu Wanling Shen Xuying Huang Xiaoyu Guo Zenglu Li 《Forest Ecosystems》 SCIE CSCD 2023年第2期252-267,共16页
Biochemical components of Moso bamboo(Phyllostachys pubescens)are critical to physiological and ecological processes and play an important role in the material and energy cycles of the ecosystem.The coupled PROSPECT w... Biochemical components of Moso bamboo(Phyllostachys pubescens)are critical to physiological and ecological processes and play an important role in the material and energy cycles of the ecosystem.The coupled PROSPECT with SAIL(PROSAIL)radiative transfer model is widely used for vegetation biochemical component content inversion.However,the presence of leaf-eating pests,such as Pantana phyllostachysae Chao(PPC),weakens the performance of the model for estimating biochemical components of Moso bamboo and thus must be considered.Therefore,this study considered pest-induced stress signals associated with Sentinel-2A/B images and field data and established multiple sets of biochemical canopy reflectance look-up tables(LUTs)based on the PROSAIL framework by setting different parameter ranges according to infestation levels.Quantitative inversions of leaf area index(LAI),leaf chlorophyll content(LCC),and leaf equivalent water thickness(LEWT)were derived.The scale conversions from LCC to canopy chlorophyll content(CCC)and LEWT to canopy equivalent water thickness(CEWT)were calculated.The results showed that LAI,CCC,and CEWT were inversely related with PPC-induced stress.When applying multiple LUTs,the p-values were<0.01;the R2 values for LAI,CCC,and CEWT were 0.71,0.68,and 0.65 with root mean square error(RMSE)(normalized RMSE,NRMSE)values of 0.38(0.16),17.56μg cm-2(0.20),and 0.02 cm(0.51),respectively.Compared to the values obtained for the traditional PROSAIL model,for October,R2 values increased by 0.05 and 0.10 and NRMSE decreased by 0.09 and 0.02 for CCC and CEWT,respectively and RMSE decreased by 0.35μg cm-2 for CCC.The feasibility of the inverse strategy for integrating pest-induced stress factors into the PROSAIL model,while establishing multiple LUTs under different pest-induced damage levels,was successfully demonstrated and can potentially enhance future vegetation parameter inversion and monitoring of bamboo forest health and ecosystems. 展开更多
关键词 Moso bamboo Chlorophyll content Equivalent water thickness PROSAIL model Multiple LUTs Pantana phyllostachysae Chao Sentinel-2A/B images
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Assessing spatiotemporal variations of forest carbon density using bi-temporal discrete aerial laser scanning data in Chinese boreal forests
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作者 Zhiyong Qi Shiming Li +3 位作者 Yong Pang Guang Zheng Dan Kong Zengyuan Li 《Forest Ecosystems》 SCIE CSCD 2023年第5期547-560,共14页
Assessing the changes in forest carbon stocks over time is critical for monitoring carbon dynamics,estimating the balance between carbon uptake and release from forests,and providing key insights into climate change m... Assessing the changes in forest carbon stocks over time is critical for monitoring carbon dynamics,estimating the balance between carbon uptake and release from forests,and providing key insights into climate change mitigation.In this study,we quantitatively characterized spatiotemporal variations in aboveground carbon density(ACD)in boreal natural forests in the Greater Khingan Mountains(GKM)region using bi-temporal discrete aerial laser scanning(ALS)data acquired in 2012 and 2016.Moreover,we evaluated the transferability of the proposed design model using forest field plot data and produced a wall-to-wall map of ACD changes for the entire study area from 2012 to 2016 at a grid size of 30 m.In addition,we investigated the relationships between carbon dynamics and the dominant tree species,age groups,and topography of undisturbed forested areas to better understand ACD variations by employing heterogeneous forest canopy structural characteristics.The results showed that the performance of the temporally transferable model(R^(2)=0.87,rRMSE=18.25%),which included stable variables,was statistically equivalent to that obtained from the model fitted directly by the 2016 field plots(R^(2)=0.87,rRMSE=17.47%).The average rate of change in carbon sequestration across the entire study region was 1.35 Mg⋅ha^(-1)⋅year^(-1) based on the changes in ALS-based ACD values over the course of four years.The relative change rates of ACD decreased as the elevation increased,with the highest and lowest ACD growth rates occurring in the middle-aged and mature forest stands,respectively.The Gini coefficient,which represents forest canopy surface structure heterogeneity,is sensitive to carbon dynamics and is a reliable predictor of the relative change rate of ACD.This study demonstrated the applicability of bi-temporal ALS for predicting forest carbon dynamics and fine-scale spatial change patterns.Our research contributed to a better understanding of the in-fluence of remote sensing-derived environmental variables on forest carbon dynamic patterns and the development of context-specific management approaches to increase forest carbon stocks. 展开更多
关键词 Aboveground carbon density Bi-temporal ALS Carbon dynamics Temporal transferability Gini coefficient
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Petrogenesis of Volcanic Rocks in the Khabr-Marvast Tectonized Ophiolite:Evidence for Subduction Processes in the South-Western Margin of Central Iranian Microcontinent 被引量:2
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作者 Azam SOLTANMOHAMMADI Mohammad RAHGOSHAY Morteza KHALATBARI-JAFARI 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2009年第5期884-892,共9页
The Late Cretaceous Khabr-Marvast tectonized ophiolite is located in the middle part of the Nain-Baft ophiolite belt, at the south-western edge of the central Iranian microcontinent. Although all the volcanic rocks in... The Late Cretaceous Khabr-Marvast tectonized ophiolite is located in the middle part of the Nain-Baft ophiolite belt, at the south-western edge of the central Iranian microcontinent. Although all the volcanic rocks in the study area indicate subduction-related magmatism (e.g. high LILE (large ion lithophile elements) / HFSE (high field strenght elements) ratios and negative anomalies in Nb and Ta), geological and geochemical data clearly distinguish two distinct groups of volcanic rocks in the tectonized association: (1) group 1 is comprised of hyaloclastic breccias, basaltic pillow lavas, and andesite sheet flows. These rocks represent the Nain-Baft oceanic crust; and (2) group 2 is alkaline lavas from the top section of the ophiolite suite. These lavas show shoshonite affinity, but do not support the propensity of ophiolite. 展开更多
关键词 alkaline lavas subduction-related magmatism tectonized ophiolite central Iranian microcontinent
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Analysis of Determinants for an Enhanced and Long-lasting Coastal Convective System by Means of a Case Study(26 July 2011) 被引量:1
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作者 Jung-Tae LEE Dong-In LEE +1 位作者 Shingo SHIMIZU Cheol-Hwan YOU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2019年第12期1327-1339,共13页
A precipitation system developed continuously along the western coastline of the Korean Peninsula and created considerable precipitation both along the coast and inland on 26 July 2011. In this study, the causes for t... A precipitation system developed continuously along the western coastline of the Korean Peninsula and created considerable precipitation both along the coast and inland on 26 July 2011. In this study, the causes for this nearshore convective system are investigated from observations and the results of model experiments. Three-dimensional radar fields clearly show that a change of wind at the surface border played an important role in the development of the nearshore convection system. The simulation results, which are very similar to the observations, show that the surface border generated and maintained the convergence zone. The roughness change enhanced the convergence, and the interaction between the deepening cold pool and downward flow maintained the convergence zone. The surface mechanical discontinuity affected by the roughness change between sea and land formed the convergence (gradient of wind stress), which induced momentum transfer to the upper layer. The cold pool created a steep gradient of potential temperature and provided the reason for the propagated convergence zone with the downward flow. The maximum value of the surface change factor, which comprises the influencing factors for the long-lasting convective system, reflects the enhancement of the system at the coast. 展开更多
关键词 COASTAL precipitation ROUGHNESS convergence zone cold POOL propagation DOWNWARD flow
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A novel index to evaluate discretization methods: A case study of flood susceptibility assessment based on random forest 被引量:2
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作者 Xianzhe Tang Takashi Machimura +2 位作者 Wei Liu Jiufeng Li Haoyuan Hong 《Geoscience Frontiers》 SCIE CAS CSCD 2021年第6期313-325,共13页
The selection of a suitable discretization method(DM) to discretize spatially continuous variables(SCVs)is critical in ML-based natural hazard susceptibility assessment. However, few studies start to consider the infl... The selection of a suitable discretization method(DM) to discretize spatially continuous variables(SCVs)is critical in ML-based natural hazard susceptibility assessment. However, few studies start to consider the influence due to the selected DMs and how to efficiently select a suitable DM for each SCV. These issues were well addressed in this study. The information loss rate(ILR), an index based on the information entropy, seems can be used to select optimal DM for each SCV. However, the ILR fails to show the actual influence of discretization because such index only considers the total amount of information of the discretized variables departing from the original SCV. Facing this issue, we propose an index, information change rate(ICR), that focuses on the changed amount of information due to the discretization based on each cell, enabling the identification of the optimal DM. We develop a case study with Random Forest(training/testing ratio of 7 : 3) to assess flood susceptibility in Wanan County, China.The area under the curve-based and susceptibility maps-based approaches were presented to compare the ILR and ICR. The results show the ICR-based optimal DMs are more rational than the ILR-based ones in both cases. Moreover, we observed the ILR values are unnaturally small(<1%), whereas the ICR values are obviously more in line with general recognition(usually 10%–30%). The above results all demonstrate the superiority of the ICR. We consider this study fills up the existing research gaps, improving the MLbased natural hazard susceptibility assessments. 展开更多
关键词 Machine learning Natural hazards Information change rate Discretization method
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Integrating cross-sensor high spatial resolution satellite images to detect subtle forest vegetation change in the Purple Mountains,a national scenic spot in Nanjing,China 被引量:1
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作者 Fangyan Zhu Wenjuan Shen +2 位作者 Jiaojiao Diao Mingshi Li Guang Zheng 《Journal of Forestry Research》 SCIE CAS CSCD 2020年第5期1743-1758,共16页
Accurate information on the location and magnitude of vegetation change in scenic areas can guide the configuration of tourism facilities and the formulation of vegetation protection measures.High spatial resolution r... Accurate information on the location and magnitude of vegetation change in scenic areas can guide the configuration of tourism facilities and the formulation of vegetation protection measures.High spatial resolution remote sensing images can be used to detect subtle vegetation changes.The major objective of this study was to map and quantify forest vegetation changes in a national scenic location,the Purple Mountains of Nanjing,China,using multi-temporal cross-sensor high spatial resolution satellite images to identify the main drivers of the vegetation changes and provide a reference for sustainable management.We used Quickbird images acquired in 2004,IKONOS images acquired in 2009,and WorldView2 images acquired in 2015.Four pixel-based direct change detection methods including the normalized difference vegetation index difference method,multi-index integrated change analysis(MIICA),principal component analysis,and spectral gradient difference analysis were compared in terms of their change detection performances.Subsequently,the best pixel-based detection method in conjunction with object-oriented image analysis was used to extract subtle forest vegetation changes.An accuracy assessment using the stratified random sampling points was conducted to evaluate the performance of the change detection results.The results showed that the MIICA method was the best pixel-based change detection method.And the object-oriented MIICA with an overall accuracy of 0.907 and a kappa coefficient of 0.846 was superior to the pixel-based MIICA.From 2004 to 2009,areas of vegetation gain mainly occurred around the periphery of the study area,while areas of vegetation loss were observed in the interior and along the boundary of the study area due to construction activities,which contributed to 79%of the total area of vegetation loss.During 2009–2015,the greening initiatives around the construction areas increased the forest vegetation coverage,accounting for 84%of the total area of vegetation gain.In spite of this,vegetation loss occurred in the interior of the Purple Mountains due to infrastructure development that caused conversion from vegetation to impervious areas.We recommend that:(1)a local multi-agency team inspect and assess law enforcement regarding natural resource utilization;and(2)strengthen environmental awareness education. 展开更多
关键词 High spatial resolution satellite images Vegetation change Direct detection method Objectoriented Purple Mountains
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Comparison between experimental and analytical results for seesaw energy dissipation systems using fluid viscous dampers
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作者 Jae-Do Kang Hiroshi Tagawa 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2016年第1期79-90,共12页
This paper presents results of experimental and numerical investigations of a seesaw energy dissipation system (SEDS) using fluid viscous dampers (FVDs). To confirm the characteristics of the FVDs used in the test... This paper presents results of experimental and numerical investigations of a seesaw energy dissipation system (SEDS) using fluid viscous dampers (FVDs). To confirm the characteristics of the FVDs used in the tests, harmonic dynamic loading tests were conducted in advance of the flee vibration tests and the shaking table tests. Shaking table tests were conducted to demonstrate the damping capacity of the SEDS under random excitations such as seismic waves, and the results showed SEDSs have sufficient damping capacity for reducing the seismic response of flames. Free vibration tests were conducted to confirm the reliability of simplified analysis. Time history response analyses were also conducted and the results are in close agreement with shaking table test results. 展开更多
关键词 seesaw energy dissipation system experimental verification shaking table test simplified analysis dynamiccharacteristic
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Reineckeiidae (Ammonoidae) Family of the Dalichai Formation in Damghan Area (East Alborz), Iran
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作者 Marjan Zadesmaeil Mahmoud Reza Majidifard +1 位作者 Seyed Hamid Vaziri Davood Jahani 《Open Journal of Geology》 2017年第6期888-914,共27页
The present study is concerning the systematic descriptions of the Middle Jurassic (Callovian) ammonite fauna from the Damghan Area (eastern Alborz) and contains a rather rich ammonite fauna. The described ammonites c... The present study is concerning the systematic descriptions of the Middle Jurassic (Callovian) ammonite fauna from the Damghan Area (eastern Alborz) and contains a rather rich ammonite fauna. The described ammonites come from the Middle part of the Dalichai Formation, consisting of an alternation of green marl, grey limestone and marly limestone. In this research, the biostratigraphy of these rocks is discussed with special emphasis on the abundant ammonite fauna (Reineckeiidae family). Altogether, 74 specimens of ammonites belonging to 14 species, 3 genera, 3 sub genera from Reineckeiidae family are described. Palaeobiogeographically the ammonite fauna is closely related to that of the sub-Mediterranean Province of the northwestern Tethys. The ammonites represent four zones, i.e. Rehmannia (Loczyceras) cf. segestena (Anceps Zone), Rehmannia (Loczyceras) reissi (Anceps Zone), Rehmannia (Loczyceras) rehmanni (Anceps Zone), Rehmannia (Loczyceras) sequanica densicostata (Coronatum Zone), Reineckeia (Tyrannites) convexa (Gracilis Zone), Reineckeia (Tyrannites) pictava (Gracilis Zone), Reineckeia (Reineckeia) anceps anceps (Anceps Zone), Reineckeia (Reineckeia) anceps elmii (Anceps Zone), Reineckeia (Reineckeia) cf. fehlmani (Anceps Zone), Reineckeia (Reineckeia) nodosa (Athleta Zone), Collotia cf. multicostat (Anceps Zone), Collotia cf. gaillardi (Coronatum Zone), Collotia cf. oxyptychoides (Athleta Zone), Collotia cf. collotiformis (Athleta Zone). 展开更多
关键词 JURASSIC Reineckeiidae Palaeobiogeographically Dalichai FORMATION ALBORZ
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Estimation of Species Richness of Permian Foraminifera in Non-Parametric Methods and Investigation of Its Change Trend in Central Alborz, Western Tethys
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作者 Mohammad Medadi Hossein Mosaddegh +1 位作者 Seyed Mohsen Aleali Mahmoud Reza Majidifard 《Open Journal of Geology》 2017年第5期666-682,共17页
Species richness of foraminifera assemblages in the Permian succession, contains Dorud, Ruteh and Nessen Formations, in Central Alborz—North of Iran, was estimated and studied based on lithostratigraphy and microbios... Species richness of foraminifera assemblages in the Permian succession, contains Dorud, Ruteh and Nessen Formations, in Central Alborz—North of Iran, was estimated and studied based on lithostratigraphy and microbiostratigraphy of Permian. We used four non-parametric estimators to investigate the species richness: Chao 2, Jackknife 1, Jackknife 2 and bootstrap. These methods estimates the species richness based on the presence/absence data of each taxon identified in the samples. We use the submenu of quadrat richness in “Past” [1] software to estimate richness in regional chronostratigraphic stages.The results show that the estimated diversity of foraminiferal assemblages with the exception of late Yakhtashian, increased constantly from Asselian to Murgabian with the highest diversity of foraminifera seen in the Murgabian. The main decrease in foraminiferal species richness happened during the Midian which corresponds to the kamura cooling event. 展开更多
关键词 PERMIAN FORAMINIFERA Species Richness CENTRAL ALBORZ WESTERN TETHYS
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Correction to:Integrating cross-sensor high spatial resolution satellite images to detect subtle forest vegetation change in the Purple Mountains,a national scenic spot in Nanjing,China
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作者 Fangyan Zhu Wenjuan Shen +2 位作者 Jiaojiao Diao Mingshi Li Guang Zheng 《Journal of Forestry Research》 SCIE CAS CSCD 2021年第5期I0001-I0001,共1页
The article "Integrating cross-sensor high spatial resolution satellite images to detect subtle forest vegetation change in the Purple Mountains,a national scenic spot in Nanjing,China",written by Fangyan Zh... The article "Integrating cross-sensor high spatial resolution satellite images to detect subtle forest vegetation change in the Purple Mountains,a national scenic spot in Nanjing,China",written by Fangyan Zhu,Wenjuan Shen,Jiaojiao Diao,Mingshi Li and Guang Zheng,was originally pub-lished electronically on the publisher’s Internet portal(currently SpringerLink)on 14 May 2019 without open access. 展开更多
关键词 PORTAL resolution NANJING
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Lithostratigraphy and Biostratigraphy of the Sarvak Formation in Wells No. 2, 16 and 66 of Rag-e-Safid Oilfield in the Southwest of Iran
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作者 Mahboubeh Jamalpour Bahauddin Hamdi Afshin Armoon 《Open Journal of Geology》 2017年第6期806-821,共16页
The lithostratigraphy and biostratigraphy specifications of the Sarvak Formation are considered to study in wells No. 2, 16 and 66 of Rag-e-Safid oilfield. They are located at the southeast of Ahwaz (the southwest of ... The lithostratigraphy and biostratigraphy specifications of the Sarvak Formation are considered to study in wells No. 2, 16 and 66 of Rag-e-Safid oilfield. They are located at the southeast of Ahwaz (the southwest of Iran). The lithology of the Sarvak Formation in all the wells mostly consists of limestone. The depth of the Sarvak Formation in well No. 2 is 720 m;in this well, the Sarvak Formation overlies the Kazhdumi Formation and underlies the Papdeh Formation. Vertical distribution of recognized foraminifera, macrofossils and calcareous Algae identifies two biozones: 1) Favusellawashitensis Range zone;2) Praealveolinacretacea-Ovalveolina ovum & Rudistfragment Ass. zone. The thicknesses of the Sarvak Formation in wells No. 16 and 66 are about 100 m and 108 m, respectively;in a part of the Sarvak Formation, drilling was completed, while its upper boundary is covered with the Papdeh Formation, in both wells. In terms of biostratigraphy studies in wells No. 16 and 66, one assemblage biozone is recognized as Praealveolinacretacea-Ovalveolina ovum & Rudistfragment Ass. Zone, similarly. Finally, the age of the Sarvak Formation is determined as the Cenomanian in three considered wells. 展开更多
关键词 LITHOSTRATIGRAPHY BIOSTRATIGRAPHY Sarvak FORMATION CENOMANIAN
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Sendai Water Pipeline Response to the 2011 Tohoku Earthquake
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作者 Kazue Wakamatu Shigeru Nagata +1 位作者 Yoshihisa Maruyama Kyoko Ozawa 《Journal of Civil Engineering and Architecture》 2016年第4期461-470,共10页
关键词 地震烈度 水管道 日本 东北 土地开发 地形变化 球墨铸铁管 维修率
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Microzoning Study for Seismic Risk Reduction in the Areas Covered Soft Soil Deposit, Japan
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作者 He Ma Takahisa Enomoto +1 位作者 Tsutomu Ochiai Shigeki Senna 《Journal of Geological Resource and Engineering》 2018年第4期160-175,共16页
关键词 菲律宾海板块 北美板块 地面状态 科学研究
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Facies Interpretation, Depositional Environment and Sequence Stratigraphy of the Gachal Formation in the Madbeiki Section, Kalmard Block, East Central Iran
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作者 Soheil Erfani Mohammad Hossein Adabi +1 位作者 Mahmood Reza Majidifard Nader Kohansal Ghadimvand 《Open Journal of Geology》 2016年第6期439-458,共20页
Deposits of Lower Carboniferous rocks in Kalmard block are recognized by Gachal informal formation, showing various characteristics in different outcrops. Lower Carboniferous deposits (Gachal formation) are composed c... Deposits of Lower Carboniferous rocks in Kalmard block are recognized by Gachal informal formation, showing various characteristics in different outcrops. Lower Carboniferous deposits (Gachal formation) are composed chiefly of carbonate, evaporite and siliciclastic rocks. This formation is composed of 198 m sandstone, limestone and dolomite as well as a small amount of shale, marl and gypsum in the Madbeiki section. This formation unconformably underlies Precambrian metamorphic deposits (Kalmard formation) while lateritic soils of lower Permian (Chili formation) are depicted overlying an erosional unconformity above this formation. According to lithologic and microscopic investigations, the deposits of Gachal formation can be divided into 1 siliciclastic petrofacies, 1 evaporite microfacies and 16 carbonate microfacies. Field observations, along with microscopic examinations, have resulted in identifying tidal flat, lagoon, shoal and open marine environments in the rocks of the studied formation. Vertical changes of microfacies and depth variation curve indicate the high thickness of the microfacies of tidal flat, lagoon and shoal environments and low thickness of the microfacies of open marine environment. The carbonate-evaporite-siliciclastic sequence of Gachal formation is made up of three third-order depositional sequence, separated each other by type 1 sequence boundary (SB1). Siliciclastic and evaporite deposits include LST system tract, and carbonate microfacies involve TST and HST system tracts, separated from each other by MFS. Gachal formation rocks in Madbeiki section are deposited in a low-angle homoclinal ramp, mostly in the inner ramp, located in the southern Paleotethys Ocean. The depositional sequence identified in Gachal formation points to the age of Lower Carboniferous, conforming to upper Kaskaskia super sequence. The upper erosional boundary between Gachal and Chili formations conform to the global-scale sea level fall. 展开更多
关键词 Lower Carboniferous Kalmard Block Gachal Formation Depositional Environment Sequence Stratigraphy
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Dolomitization Mechanism Based on Petrography and Geochemistry in the Shotori Formation (Middle Triassic), Central Iran
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作者 A. Rahimi M. H. Adabi +2 位作者 A. Aghanabati M. R. Majidifard A. M. Jamali 《Open Journal of Geology》 2016年第9期1149-1168,共20页
Middle Triassic carbonate sequences of Shotori Formation have a thickness of 70 m and are deposited Robat-e-Kalmard region of Tabas city in Central Iran basin. Gradationally and conformably overlying Sorkh shale Forma... Middle Triassic carbonate sequences of Shotori Formation have a thickness of 70 m and are deposited Robat-e-Kalmard region of Tabas city in Central Iran basin. Gradationally and conformably overlying Sorkh shale Formation, Shotori Formation, mostly composed of medium to thick dolomites (50 m), interbeded with thin lime and sandstones, is disconformable by a laterite horizon at its upper boundary. This Formation mainly consists of fine-to-coarsely crystalline dolomites. According to petrographic (fabric and grain size) and geochemical (elemental analysis of Ca, Mg, Na, Sr, Fe, Mn) evidence, five various types of dolomites were recognized in Shotori Formation. This variety results from early and late diagenetic processes, triggering a change in dolomitizing fluids and thereby forming various dolomites. Geochemical studies have revealed that the dolomites of Shotori Formation have formed under meteoric diagenesis and reducing conditions. Various dolomitization mechanisms are proposed for various types of dolomites;that is to say, Sabkha model is considered for type 1 dolomite, mixing zone model for type 2 and 3 dolomites and burial model for type 4 and 5 dolomites. 展开更多
关键词 DOLOMITIZATION PETROGRAPHY GEOCHEMISTRY Shotori Formation Central Iran
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Facies Interpretation, Depositional Environment and Sequence Stratigraphy of the Sartakht Formation in the Bakhshi Section, Located in Kalmard Block, East-Central Iran
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作者 Bibi Haniyeh Emraninasab Mohammad Hossein Adabi +1 位作者 Mahmoodreza Majidifard Nader Kohansal Ghadimvand 《Open Journal of Geology》 2016年第5期314-329,共16页
Permian rocks in Kalmard block are recognized with Khan Group, enjoying various characteristics in different outcrops. This group is made up of three informal formations, namely Chili, Sartakht and Hermez. Middle Perm... Permian rocks in Kalmard block are recognized with Khan Group, enjoying various characteristics in different outcrops. This group is made up of three informal formations, namely Chili, Sartakht and Hermez. Middle Permian deposits (Sartakht formation) are composed chiefly of sandstone and carbonate rocks. This formation is composed of 58.6 m sandstone and dolomitic limestone in the Bakhshi section. Lower Permian carbonate deposits (Chili formation) unconformably underlie this formation while lateritic paleosols of upper Permian (Hermez formation) are depicted overlying an erosional unconformity above this formation. According to lithologic and microscopic investigations, the deposits of Sartakht formation can be divided into 2 siliciclastic petrofacies and 12 carbonate microfacies. Field observations, along with microscopic examinations, have resulted in identifying tidal flat, lagoon, shoal and open marine environments in the rocks of the studied formation. Vertical changes of microfacies and depth variation curve point to the high thickness of the microfacies of lagoon and shoal environments and low thickness of the microfacies of tidal flat and open marine environments. The carbonate-siliciclastic sequence of Sartakht formation is made up of a third-order depositional sequence, separated from carbonate depositions of lower Permian (Chili formation) and lateritic paleosols of upper Permian by type 1 sequence boundary (SB1). Siliciclastic deposits include LST system tract, and carbonate microfacies involve TST and HST system tracts, separated from each other by MFS. Sartakht formation rocks in Bakhshi section are deposited in a low-angle homoclinal ramp, mostly in the inner ramp, located in the south of Paleotethys Ocean. The depositional sequence identified in Sartakht formation points to the age of middle Permian, conforming to middle Absaroka II supersequence. The upper erosional boundary between Sartakht and Hermez formations conforms to the global-scale sea level fall. 展开更多
关键词 Middle Permian Kalmard Block Sartakht Formation Depositional Environment Sequence Stratigraphy
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Impact of Labor Transfer on Agricultural Land Use Conversion at Rural Household Level Based on Logit Model 被引量:9
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作者 ZHONG Taiyang ZHANG Xiuying HUANG Xianjin 《Chinese Geographical Science》 SCIE CSCD 2008年第4期300-307,共8页
Since land and labor force are primary resources to be used and controlled by rural households, the allocation of labor forces will influence land uses, and further lead to land use conversion. The present study used ... Since land and labor force are primary resources to be used and controlled by rural households, the allocation of labor forces will influence land uses, and further lead to land use conversion. The present study used the Binary Logit model to investigate the influence of labor force transfer, characteristics of rural households, location, and land market on agricultural land use conversion at rural household level. This study was conducted based on 329 valid questionnaires, which were obtained in Changshu, Rudong, and Tongshan counties, respectively representing the southern, middle and northern areas of Jiangsu Province. The results showed that land market participation, location, zonal difference and labor transfer had strong influences on agricultural land use conversion. The participation of land market had a strong positive effect on land use conversion, especially for the farmland converted to the fishpond. The nearer to the county seat, the more conversion of land use occurred. Particularly, the labor force transfer caused by wage employment decreased this conversion probability, while the labor transfer caused by self-employment led to more conversion; and the increasing of income from labor transfer increased the conversion. Moreover, land use con- versions demonstrated zonal difference, which were more in Rudong and Changshu counties than in Tongshan County, and the factors influencing this conversion were different in the three regions. 展开更多
关键词 农业土地 利用率 劳动力转换 农业家庭
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Classification and Net Primary Productivity of the Southern China's Grasslands Ecosystem Based on Improved Comprehensive and Sequential Classification System(CSCS) Approach 被引量:6
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作者 SUN Zheng-guo SUN Cheng-ming +2 位作者 ZHOU Wei JU Wei-min LI Jian-long 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2014年第4期893-903,共11页
This research classified vegetation types and evaluated net primary productivity (NPP) of southern China's grasslands based on the improved comprehensive and sequential classification system (CSCS), and proposed ... This research classified vegetation types and evaluated net primary productivity (NPP) of southern China's grasslands based on the improved comprehensive and sequential classification system (CSCS), and proposed 5 thermal grades and 6 humidity grades. Four classes of grasslands vegetation were recognized by improved CSCS, namely, tundra grassland class, typical grassland class, mixed grassland class and alpine grassland class. At the type level, 14 types of vegetations (9 grasslands and 5 forests) were classified. The NPP had a trend to decrease from east to west and south to north, and the annual mean NPP was estimated to be 656.3 g C m-2 yr-1. The NPP value of alpine grassland class was relatively high, generally more than 1200 g C m2 yr-1. The NPP value of mixed grassland class was in a range from 1 000 to 1200 g C m-2 yr-1. Tundra grassland class was located in southeastern Tibet with high elevation, and its NPP value was the lowest (〈600 g C m'2yrl). The typical grassland class distributed in most of the area, and its NPP value was generally from 600 to 1000 g C m-2 yr-1. The total NPP value in the study area was 68.46 Tg C. The NPP value of typical grassland class was the highest (48.44 Tg C), and mixed grassland class was the second (16.54 Tg C), followed by alpine grassland class (3.22 Tg C), with tundra grassland class being the lowest (0.25 Tg C). For all the grasslands types, the total NPP of forest meadow was the highest (34.81 Tg C), followed by sparse forest brush (16.54 Tg C), and montane meadow was the lowest (0.01 Tg C). 展开更多
关键词 improved CSCS hydro-thermal pattern southem China grasslands classes and types net primary productivity (NPP)
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