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Constraints on early Paleozoic magmatic processes and tectonic setting of Inexpressible Island, Northern victoria Land, Antarctica

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Advances in Polar Science 2019年第1期30卷 52-69页

作者： CHEN Hong WANG Wei ZHAO Yue Institute of Geomechanics Chinese Academy of Geological Sciences Key Laboratory of Paleomagnetism and Tectonic Reconstruction of Ministry of Natural Resources

During the Cambrian and Ordovician, widespread magmatic activity occurred in the Ross Orogen of central Antarctica, forming the Granite Harbor Intrusives and Terra Nova Intrusive Complex. In the Terra Nova Intrusive Complex, the latest magmatic activity comprised the emplacement of the Abbott Unit(508 Ma) and the Vegetation Unit(～475 Ma), which were formed in different tectonic settings. Owing to their similar lithological features, the tectonic transformation that occurred between the formation of these two units has not been well studied. Through a detailed geological field investigation and geochemical and geochronological analyses, four types of magmatic rock—basalt, syenite, mafic veins, and granite veins—were identified on Inexpressible Island, Northern victoria Land. Our SHRIMP(Sensitive High Resolution Ion Micro Probe) zircon U–Pb ages of the basalt and the granite veins are 504.7 ± 3.1 and 495.5 ± 4.9 Ma, respectively. Major-and trace-element data indicate a continental-margin island-arc setting for the formation of these two rock types. The zircon U–Pb ages of the syenite and the monzodiorite veins are 485.8 ± 5.7 and 478.5 ± 4.0 Ma, respectively. Major-and trace-element compositions suggest a collisional setting for the former and an intracontinental extensional setting for the latter. These results elucidate the evolution from subduction to collision and intracontinental extension in Northern victoria Land during the 20 Ma spanning the late Cambrian–Early Ordovician and improve our understanding of the tectonics and evolution of the Ross Orogen in the Transantarctic Mountains.

关键词： Northern victoria Land Ross Orogen Early Paleozoic magmatism island-arc intracontinental extension

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Characteristics Analysis and Implications on the COVID-19 Reopening of victoria, Australia

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The Innovation 2020年第3期1卷 20-21页

作者： Lei Zhang Yusha Tao Guihua Zhuang Christopher K.Fairley China-Australia Joint Research Center for Infectious Diseases School of Public HealthXi’an Jiaotong University Health Science CenterXi’anShaanxi 710061PR China Melbourne Sexual Health Centre Alfred HealthMelbourneAustralia Central Clinical School Faculty of MedicineNursing and Health SciencesMonash UniversityMelbourneVICAustralia Department of Epidemiology and Biostatistics College of Public HealthZhengzhou UniversityZhengzhou450001 HenanChina

By 24 September 2020,the SARS-COV-2 epidemic had led to a total of 26,983 infections and 861 deaths in Australia,resulting in a significant disease burden on its health care system and disruption to its *** State of victoria is the most severely affected Australian state and accounts for 74.5%of all infections and 89.7%deaths in *** the epidemic in victoria is critical to the impact of the national *** response to the first outbreak of the epidemic,victoria declared a state of emergency on 16 March and implemented stage 2 restrictions from 25 March to 25May(first lockdown)with restrictions on major events,traveling,and social contacts(Figure 1A).In contrast,much stricter stage 3 and subsequent stage 4(second lockdown)restrictions were implemented inmetropolitan Melbourne and regional victoria between the 9 July and 13 September in response to a substantially larger second outbreak since late *** restriction measures have been effective,and the epidemic has seen a major decline from 500 to 700 cases/day in early August to 30–50 cases/day in early *** preparation for reopening the economy,the victorian government declared a COVID-19 roadmap for reopening on 9 September.1 In brief,the reopening plan for metro Melbourne requires the city to maintain a consistently declining trend of the epidemic,with the ease of restrictions in proportion to the number of the daily confirmed *** restrictions are less stringent for regional *** plan envisions complete elimination of the virus for 28 days state-wide before victoria is allowed to return to a“COVID normal”scenario.

关键词： victoria return Figure

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victoria＆Albert

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明日风尚 2009年第11期 199-199,16页

作者：黎坚惠《明日风尚》

香港有很多维多利亚,维多利亚公园、维多利亚港,学校、团体、品牌,耳熟能详,理所当然,但原来我们对维多利亚的认识很少。我对她的认识仅限于英国文学堂,明白维多利亚时代禁欲式的价值,衣服得盖上颈,是道德重整的年代。

关键词： victoria Albert 上管英国史人物性格少女时代刘嘉玲这一天定镜 Julian

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Morphometric Relationships among the Clariid Fishes of the Lake victoria Basin, Tanzania

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Open Journal of Marine Science 2015年第1期5卷 26-32页

作者： Chacha John Mwita Department of Aquatic Sciences and Fisheries College of Natural and Applied Sciences University of Dar es Salaam Dar es Salaam Tanzania

Six hundred and fifty-eight specimens of the Clariidae were collected from seven localities in the Lake victoria basin and the Malagarasi wetland, Tanzania. A total of three hundred unadjusted morphometric measurements and meristic counts were analysed with the aim of assessing the adequacy of morphometric technique to delineate the clariid species occurring in theLake victoriabasin. Results showed that morphometrics augmented by multivariate analysis (PCA, DCA and cluster analysis) amalgamated the clariid fishes into three groups, the?Clarias alluaudi/C. werneri,?C. gariepinus/C. liocephalus?andClariallabes petricola. Although other workers have used this technique, the present study concluded that, standing alone morphometrics is not a substitute for external morphology in the identification of clariid fish species, as it failed to separate the clariids into their respective taxonomic species. The technique, however, insinuates the regressional morphological relationships among the clariids occurring in the Lake victoria basin.

关键词： Morphology Regression Clariids Lake victoria

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Ecological Devastation in Lake victoria: Part A: Thermal Structure and Anoxia

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Open Journal of Ecology 2015年第7期5卷 287-298页

作者： Moshe Gophen Migal-Scientific Institute Kiryat Shemone Israel

Lake victoria is the second (excl. Caspian Sea) largest lake in the world by surface area and 7th by Volume. The lake and catchment territories are shared between three countries, Kenya, Uganda and Tanzania. A research was carried out during 1990-1992 exploring the changes of the thermo-chemical structure occurred after the invasion of Nile Perch. Results of changes of physico-chemical (Temperature, DO and pH) conditions are summarized in this paper. The anoxic conditions by space and time were enhanced. Enhancement of pollutant supply from anthropogenic developments of terrestrial sources and atmospheric dust deposition accompanied by the deleterious effects of the Nile Perch invasion caused enhancement of anoxia in the lake in space and time. The combination of bottom-up nutrient supply and strong mixing conditions, expressed as low RTR values accelerate phytoplankton growth rate and production. The surplus of organic matter originated from algal biomass, enhanced anoxia.

关键词： Lake victoria Kenya Nile Perch Anoxia Thermal Stability

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A PRELIMINARY APPROACH TO THE GEOTECTONIC EVOLUTION HISTORY AND MINERLIZATION IN victoria, AUSTRALIA

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Geotectonica et Metallogenia 2001年第1期25卷 37-44页

作者： DAI Ta-gen and CHEN Gua da (Dept. of Geology, Central South Univ., Changsha 410083, China) Dept.of Geology Central South Univ.Changsha410083China

According to the available data and field research, based on the diwa theory, the authors have studied the geotectonic evolution history and the associated minerlization in the victoria area. It has been shown that this area is in fact a part of the Lachlan diwa region. The victoria area can be divided into geodome fault fold zone and subsidence zone. The former can be subdivided into three zones, from west to east, which are western uplift zone, central depression zone and eastern uplift zone. The evolution history of the victoria area can be divided into four stages——Pregeosyncline, geosyncline, plateform and diwa. Each stage has distinct sedimentary, magmatic and structural features. Of the four stages, diwa stage is the most important for minerlization. Diwa stage started in the Devonian. During the development of diwa, a number of granites, which are characterized by high SiO 2 and Na 2O+K 2O, were formed. The granites were abundance with mineral forming material. On the other hand, diwa geotectonism reformed and enriched the geosynclinal or platform ore deposits. Therefore, most of the ore deposits that occurred in the victoria area are, more or less, related with diwa tectonism.

关键词： Diwa theory minerlization geotectonics victoria

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The Spatial and Temporal Characteristics of Rainfall over the Lake victoria Basin of Kenya in 1987-2016

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Atmospheric and Climate Sciences 2020年第2期10卷 240-257页

作者： Wabwire Odhiambo Evans S. N. Mukhovi I. A. Nyandega Catholic University of Eastern Africa Nairobi Kenya University of Nairobi Kenya Nairobi Kenya

Climate extremes have increased in the recent past and they are further being exacerbated by climate change and variability. In this paper, we sought to determine rainfall characteristics over the Lake victoria Basin of Kenya in 1987-2016, as a basis of understanding climate variability. The methodology used included;Standardized Precipitation Index to depict variability, coefficient of variation for spatial analysis and the Mann-Kendall test to test the presence of trends in data. We established that Lake victoria basin is relatively wet through-out the year, with two distinct rainfall seasons March-April-May (MAM) and October-November-December (OND) that support human livelihood and ecology. The normal wetness conditions have declined over time, paving way for both dry and wet extremes conditions between 1997-1998 and 2002-2006, respectively. The rainfall extremes have become frequent in the last decade in 2007-2016. We also established a decline in the MAM rainfall seasons, and an increase during the October-December rainfall seasons in 1987-2016. Furthermore, the number of rainy days has declined with the onset and cessations of both long rains and short rains having shown a variability of at least 50% and 30% respectively, in a range of about 100 to 200 Julian days. The decline in wet condition is likely to affect economic activities especially the rainfed agriculture. The changing rainfall trends over the basin therefore, call for proper human livelihood planning and ecological monitoring in order to achieve ecological sustainability.

关键词： Climate Variability Seasonal Rainfall Intra-Seasonal Rainfall Characteritics and Lake victoria Basin

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Influence of Land Use Activities on Spatial and Temporal Variation of Nutrient Deposition in Mwanza Region: Implication to the Atmospheric Loading to the Lake victoria

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Atmospheric and Climate Sciences 2013年第2期3卷 224-234页

作者： Said Ali Hamad Vuai John D. Ibembe Nancy W. Mungai Department of Chemistry College of Natural and Mathematical Sciences Department of Crop Science Egerton University Kenya Department of Humanities Busoga University Uganda

Increase in population growth and the associated activities have increased the nutrient input to the Lake victoria through atmosphere and river discharge. Atmospheric input of nutrient is believed to exceed that of river discharge due to relatively higher contribution of water mass to the Lake from atmosphere. However, precipitation characteristics with respect to nutrients have not been well studied to allow qualification and quantification of atmospheric contribution to the Lake victoria. This study was conducted to investigate influence of land use activities on spatial and temporal variation of nutrient inputs from atmosphere and to estimate atmospheric loading to the Lake victoria. The results revealed that there is significant spatial and temporal variation of nutrient deposition in the study area. High concentrations of nutrients were observed during short rains starting from September to December. This was attributed to dissolution of nutrients from soil particals and ash residues due to biomass burning accumulated in the atmosphere during dry season of June to August. Spatial variation of nutrients reflects land use activities. Urban and peri-urban areas showed very high concentration of nitrate nitrogen due to industrial and vehicle emission while rural area showed high concentration of phosphorous species and reduced forms of nitrogen species reflecting agricultural activities and animal keeping. Generally, nutrient deposition load was higher in rural area compared to urban with respective values of 15.5 and 13.9 kg·haˉ1·yˉ1 for total nitrogen and 6.1 and 2.8 kg·haˉ1·yˉ1 for total phosphorous. These results suggest that in order to realize significant reduction of nutrient input to the Lake victoria, measures should be taken to control agricultural activities through proper land use planning. The measure may be directed to reduce biomass burning, emission from industries and vehicle as well as animal residue.

关键词： Nutrient Landuse Lake victoria Precipitation Atmospheric Pollution

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Implications of Land Use Land Cover Change and Climate Variability on Future Prospects of Beef Cattle Production in the Lake victoria Basin

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American Journal of Climate Change 2015年第5期4卷 461-473页

作者： Japhet Joel Kashaigili Emmanuel Zziwa Siwa Ernest Emma Laswai Bernard Musana Segatagara Denis Mpairwe Reuben Mpuya Joseph Kadigi Cyprian Ebong Samuel Katambi Mugasi Germana Henry Laswai Mutimura Mupenzi Polycarp Jacob Ngowi Ibrahim Lwaho Kadigi Sokoine University of Agriculture Morogoro Tanzania Makerere University Kampala Uganda Association for Strengthening Agricultural Research in Eastern and Central Africa (ASARECA) Entebbe Uganda Tanzania Forestry Research Institute (TAFORI) Morogoro Tanzania Rwanda Agriculture Board (RAB) Kigali Rwanda National Agricultural Advisory Services (NAADS) Kampala Uganda

This paper presents the lessons learnt from a research project titled “Improving Beef Cattle Productivity for Enhanced Food Security and Efficient Utilization of Natural Resources in the Lake victoria Basin” which includes Tanzania, Uganda and Rwanda. The key focus is on the implications of land use land cover change and climate variability on the future prospects of beef cattle production in this region. The study utilizes information and data from natural resources and climate components to deduce the impact of land use and land cover changes on climate variability. Additional analysis is conducted to summarize the land use and land cover data to carry out analysis on climate data using the Mann-Kendal test, linear regression and moving averages to reveal patterns of change and trends in annual and seasonal rainfall and temperature. The findings reveal that the study areas of Rwanda, Uganda and Tanzania in the Lake victoria Basin (LVB) have changed over time following land cover manipulations and land use change, coupled with climate variability. The grazing land has been converted to agriculture and settlements, thereby reducing cattle grazing land which is the cheapest and major feed source for ruminant livestock production. Although the cattle population has been on the increase in the same period, it has been largely attributed to the fact that the carrying capacity of available grazing areas had not been attained. The current stocking rates in the LVB reveal that the rangelands are greatly overstocked and overgrazed with land degradation already evidenced in some areas. Climate variability coupled with a decrease in grazing resources is driving unprecedented forage scarcity which is now a major limiting factor to cattle production. Crop cultivation and settlement expansion are major land use types overtaking grazing lands;therefore the incorporation of crop residues into ruminant feeding systems could be a feasible way to curtail rangeland degradation and inc

关键词： Beef Cattle Production Climate Variability Crop Residues Land Use Land Cover Change Lake victoria Basin

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Implications of Papyrus (<i>Cyperus papyrus</i>L.) Biomass Harvesting on Nutrient Regulation in Nyando Floodplain Wetland, Lake victoria, Kenya

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Open Journal of Ecology 2019年第10期9卷 443-457页

作者： P. J. K. Rongoei S. T. Kariuki Department of Environmental Sciences Egerton University Njoro Kenya Department of Biological Sciences Egerton University Njoro Kenya

Harvesting of papyrus biomass plays a significant role in regulating ecosystem services of which one of them is nutrient uptake and cycling. Despite Lake victoria’s wetlands being important, little is understood about its role in nutrient uptake and removal. Although there have been studies done in these wetlands, there is inadequate understanding on the implication of unselective biomass harvesting on the water quality of Lake Vitoria. At the same time, these wetlands are threatened by livelihood-related pressures which are driven by extreme hydrological regimes. This study focused on Nyando floodplain wetland located in the Eastern part of the shores of Lake victoria which is a lifeline to many rural communities living around the lake. Papyrus biomass harvesting was assessed in two study sites of Nyando wetland and at different seasons in order to determine its implication on nutrient regulating services. Participatory tools, field survey, observation, field measurements and laboratory analysis were used. Harvesting of papyrus removed 530.6 Kg N/g DM/ha/day and 97 Kg P/g DM/ha/day in Ogenya while 771.2 Kg N/g DM/ha/day and 109.2 Kg P/g DM/ha/day were removed in Wasare. However, addition of nutrients to the wetland may lead to the problem of eutrophication especially at the site where interaction of wetland and lake water occurs. Understanding the role of papyrus harvesting patterns is crucial for better planning and management of this complex resource in a changing environment.

关键词： Papyrus Biomass Growth Stages Nutrients Nyando Wetland Lake victoria

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