Extreme Southern Part Research Articles

Modelling spatial distributions of sediments fingerprinting in the Ruvu Basin of Tanzania without continuous sediment monitoring

This study investigates various hinterlands’ contribution of sediments into the sub-basin known as Ruvu that comprises Mindu, Kibungo, Mvuha and Mindu catchments of Morogoro, Eastern Tanzania. An integrated geochemical and isotopic data were used to constrain this. Strategic sampling of basement and silty-sized sediments was conducted and the data were modelled using mass-balance computations. This approach revealed that, more than 70% of suspended sediments in the Mgeta River originate from Kigalamila, Sezima, Kingule, Mafumbo and Kibuko areas. Thus, hills north of Kisaki are major contributors of sediments with less contribution from the southern terrain. After modelling of the data from Mvuha sub-catchment, results suggest that the sediments (~50%) originate from Msuluzi area and significant erosion comes from Vihengele region. Evidence for Vihengele is also due to elevated CaCO3 abundances in the Mvuha samples from the calcareous rocks. Sediments in the Mindu sub-catchment largely originate from Msaga and Monde areas that are dominated by granulites and gneisses based on simulated mixing calculations. Thus, the extreme southern part of the sub-catchment is more prone to erosion. Sediments of more than 47% for the Kibungo sub-catchment originate from the Mfizigo area. However, no significant erosive activities in the catchment were noted.

The lichen genera Gondwania and Transdrakea gen. nov. (Teloschistaceae) - speciation in three southern continents

Within the lichen family Teloschistaceae, a high number of genera are restricted to the extreme southern part of the Southern Hemisphere. The taxonomy and phylogeny of the southern genus Gondwania have been analyzed based upon fieldwork in Antarctica, Patagonia, New Zealand and Tasmania and subsequent studies including molecular methods. Five species are accepted in the genus Gondwanea including G. inclinans and G. joannae that are combined into the genus. Two species are included in the neighboring new genus Transdrakea, T. alacalufes, a saxicolous species from Patagonia, which is described as new to science and T. schofieldii. Based on molecular data, Austroplaca imperialis is described as a new species to accommodate Patagonian specimens previously named G. regalis. Even though morphologically very similar, the two species are distinct based on molecular and chemical characters and distribution. Gondwania and Transdrakea are chemically homogenous with parietin as the very dominant compound; Transdrakea has a very reduced thallus, whereas Gondwania includes species with crustose thalli, as well as species with fruticulose growth habits. G. inclinans and G. cribrosa are only known from Australia/New Zealand. G. regalis, G. joannae and T. schofieldii are only known from Antarctica. G. sublobulata is confirmed from Patagonia and the Falkland Islands, but Antarctic specimens previously named G. sublobulata belong to G. joannae. G. sejongensis is shown to be a synonym to G. joannae. A key to Gondwania and Transdrakea species is presented.

Characterizing groundwater and surface water interaction using geological, environmental tracers (222Rn, EC, δ18O, and δ2H) and baseflow index methods for part of the Upper Awash and the adjacent Blue Nile Basin, Ethiopia

Characterization of groundwater-surface water interaction using a combined approach of geological, environmental tracers (222Rn, EC, δ18O, and δ2H) and baseflow index in a complex geological environment was carried out for part of the Upper Awash and adjacent Blue Nile Basins. In this work, total measurements of 59 water samples were used (52 from different reaches of main Rivers and tributaries, 4 from springs, and 3 from boreholes) for 222Rn analysis in dry and wet seasons, along with recent 8–20 years of daily stream flow records from 11-gauge stations. For sub-surface inference, regional geological structures and lineament density zones were determined using Kriging interpolation techniques. 222Rn values for the river and streams show 2.7–468 Bq/m3 during the rainy season and 17.1–1467 Bq/m3 for the non-rainy season. The credible justification related to moderate to high seasonal 222Rn values (100–400 Bq/m3) in the upstream parts of the two Basins, including areas falling along the surface water divide between the two adjacent Basins, shows a link between groundwater and surface water systems. In the same area, a very high mean annual baseflow index (BFI >0.5) is dominantly associated with high lineament density (0.9 < LD < 3.0), regional faults, and geologic units of highly permeable scoriaceous basalt, rift basalt, and fractured ignimbrite units. Relatively, low 222Rn (<100 Bq/m3) in both seasons and low baseflow index (BFI <0.35) values mainly in the central part of the Upper Awash basin are attributed to existing impervious superficial deposits (alluvial, tuff and ash). This, in turn, shows the poor connection between the groundwater and surface water systems in the central plain part of the Upper Awash Basin and, as also evidenced by the storage of floodwater for an extended time after the end of the rainy season, prove poor connectivity between groundwater and surface water systems. The very high 222Rn (400–1467 Bq/m3) with varied mean annual baseflow index (0.35 < BFI <0.5) at different stations in the extreme southern and southeastern parts of the Upper Awash Basin show Awash River is gaining from the aquifer system through highly fractured basalt and fractured ignimbrite geologic units. Evidence from analysis of measured electrical conductivity and stable isotopes (δ18O, δ2H) generally agree with the observed 222Rn value and baseflow analysis.

The extreme southern origins of globality: Circumnavigation, habitability, and geopolitics

AbstractThis article analyses how the first circumnavigation of the world, from 1519 to 1522, introduced South America as a key space in the formation of the ‘global’, thus producing a historical point of inflection. We examine the commercial and political plans and networks that began to function as a result of this new connectivity, which turned the American continent into a major global axis. The analysis focuses on the way in which this voyage gave new prominence to an unexplored region of the world, namely the southernmost tip of America, thus changing the notion of habitability that had prevailed for centuries in Europe. These changes questioned the authority of ‘ancient’ Greek thinkers and strengthened a European historical narrative that appropriated the discovered territories and distinguished the extreme southern part of America from other southern regions, as symbolized through figures such as the Patagonian giants. I consider these changes based on evidence from Spanish sources.

Spatial relationships between fishes and amphibians: implications for conservation planning in a Neotropical Hotspot.

Species distribution patterns are widely used to guide conservation planning and are a central issue in ecology. The usefulness of spatial correlation analysis has been highlighted in several ecological applications so far. However, spatial assumptions in ecology are highly scale-dependent, in which geographical relationships between species diversity and distributions can have different conservation concerns. Here, an integrative landscape planning was designed to show the spatial distribution patterns of taxonomic and functional diversity of amphibians and fishes, from multiple species traits regarding morphology, life history, and behavior. We used spatial, morphological, and ecological data of amphibians and fishes to calculate the functional diversity and the spatial correlation of species. Mapping results show that the higher taxonomic and functional diversity of fishes is concentrated in the West Atlantic Forest. Considering amphibians, are located in the East portion of the biome. The spatial correlation of species indicates the regions of the Serra do Mar and the extreme southern part of the Central Corridor as the main overlapped species distribution areas between both groups. New key conservation sites were reported within the Brazilian Atlantic Forest hotspot, revealing cross-taxon mismatches between terrestrial and freshwater ecosystems. This study offers useful spatial information integrating suitable habitats of fishes and amphibians to complement existing and future research based on terrestrial and freshwater conservation. New priorities for biodiversity conservation in rich-species regions highlight the importance of spatial pattern analysis to support land-use planning in a macroecological context.

Natural Radioactivity and Radiological Implications of Stream Sediments at Wadi Aidib Area, South Eastern Desert, Egypt

Wadi Aidib lies at the extreme southern part of the Eastern Desert, Egypt, between 22o15'- 22o21' N and Longitudes 36o20'-36o30' E. Landsat ETM+ false color composite image (bands 3, 2, 1) was used for regional discrimination for different rock types and provide an excellent base map for the study area, morphological features of the stream deposits of the study area were known from Landsat ETM images, in addition to several field observations. The studied stream sediments accumulate in the form of alluvial fans. They are mainly composed of sands, gravels, boulders and contain some heavy valuable minerals which are derived from metavolcanics, metasediments, quartz diorite, biotite and alkali feldspar granites. Heavy liquid separation and magnetic separation techniques in addition to microscopic examination for the studied stream sediment samples were applied to identify the heavy minerals in these sediments. These minerals are represented by magnetite, ilmenite, rutile, garnet, zircon, monazite and Green silicates. The distribution of some elements in the study area is clear that they are concentrated near the outcrops of granites. The radionuclide concentrations were measured in different stations using a calibrated gamma-ray portable detector (RS 230) and the heavy minerals causing radioactivity were separated by heavy liquids and determined by binuclear and environmental scanning electron microscopes. Uranium ranges between 5.25 and 32.05 ppm with an average of 16.63 ppm, Th between 4.4 and 17 ppm with 11.34 ppm as an average and potassium fall between 1.8 and 5.15% with an average of 3.4 %. Correlation between soil radioactivity and its mineralogical content indicate that the high radionuclides contents are mainly attributed to the presence monazite which is the principal source of both uranium and thorium. Uranium high concentrations could be related to the metamict zircon. Absorbed Dose Rate (D), annual effective dose equivalent radium equivalent activity, external and internal hazard index, in addition to activity gamma index caused by gamma emitting natural radionuclide are determined from the obtained values of 238U, 232Th and 40K. Fairly, some of the studied stations do not satisfy the universal standards. 40K plays the main and most important role in dose rate contribution.

Spatial patterns of long-term trends in thunderstorms in India

Long-term trends in the frequency of thunderstorm days are investigated using fifty years of data recorded by weather observatories throughout India. An attempt has been made to identify whether the trends are spatially cohesive and collocated with regions with maximum of thunderstorm days. This analysis of trends is significant, since most of the weather over India is of convective origin and has devastating impact on life and property. There are three thunderstorm maximum regions (a) northwest Indian Himalayas and adjoining Pakistan, (b) east India and (c) extreme southern parts of peninsular India. The results of the study revealed on a monthly scale, the frequency of thunderstorm days has a consistent spatially cohesive decreasing trend over east central and northeast India, collocated with the intra-annually shifting maximum of thunderstorm activity. The trend is more diffused for the thunderstorm maxima over north and south peninsular India. Comparison with rainfall trends from previous studies indicates that this decreasing trend of thunderstorm days is in phase with decreasing trends in rainfall activity over east central and northeast Indian regions. Detailed analysis indicates that frequency of thunderstorm days over these regions decreased during the latter half of the twentieth century followed by gradually increasing trend. This corresponds to a global warming hiatus and matches similar findings around the world. It seems likely that the decreasing moisture inflow from the surrounding oceans into the Indian subcontinent throughout the year due to weakening of the land-sea thermal gradient is causing a decreasing trend in the convection during this period. Over north and south peninsular India, where circum-global planetary waves play an important role in triggering convection, the strengthening of these waves offsets the effect of the generally decreasing moisture.

Origin of Neoproterozoic metamorphic suites along the Western Segment of Allaqi Shear Zone, Southern Egyptian Nubian Shield

The Neoproterozoic basement complex of the western segment of the Allaqi Shear Zone (ASZ) in the extreme southern part of the Egyptian Nubian Shield comprises four main lithologic units: gneisses, amphibolites, island arc metasediments, and intrusives. In the present study, these units investigated at the outcrop scale, as well as petrographically and geochemically. Gneisses are subdivided into three types: hornblende, muscovite, and biotite gneisses. The hornblende and muscovite gneisses have para-gneissic origin, while the biotite gneiss has igneous protolith. Amphibolites have intermediate andesitic to basaltic andesite composition, with igneous origin, and were formed in island-arc environments. The metagabbros are subalkaline and have within-plate geochemical characteristics. The metasediments involve graphite-muscovite, albite, chlorite, biotite-muscovite, carbonate, and tremolite-actinolite schists, in addition to metagreywackes. The bulk chemistry of metasedimentary succession revealed their formation within active continental margin setting with pelitic to semi-pelitic and psammitic precursor. The previously mentioned lithologic units are poly deformed and intensively affected by shearing and thrusting. These structures strike in various direction: WNW-ESE, NNE-SSW, NW-SE, NW-SE, and E-W, which are consistent with the automatic and manual principal component analyses (PCA) lineament extraction.

Spatial-Temporal Assessment of Formation of Nature Reserve Fund of Sumy Region

Purpose. To assess the main trends in the formation of nature reserves and the degree of protection of the territory of Sumy region to determine the directions of development of the regional ecological network. Methods. Methods of historical analysis, statistical processing, spatial modeling, evaluation and generalization of the obtained data are used. Results. During the study period since 1991, the area of ​​NPF has increased 5.44 times, and the number of NPF objects - almost 2 times and in 2019 is 275 units. Comparison of administrative districts of Sumy region by the number of NPF objects allows to determine the districts - "leaders": Romensky (37), Sumy and Lebedyn (25 pieces each), Krolevets (24) and districts - outsiders - Buryn (5), Shostka (7) and Velykopysarivsky 8). By the area of ​​the nature reserve fund "leaders" - Putivl district (39298.55 hectares) and Konotop district (32440.7 hectares). The discrepancy between a large number of objects and the area of ​​the NPF prompted the determination of the percentage of reserves and modeling of the relationship between these three indicators. Based on cartographic visualization and statistical modeling, recommendations have been developed, the main of which are: intensification of the creation of NPF objects of local significance, first of all, in the areas that are most "lagging behind" in the process of bequest; renewal of previously rejected NFP Projects and facilitate their approval; initiating activities to promote tourist routes on unique natural, historical, ethnographic sites of the NPF for economic support of communities. Conclusions. It is established that the degree of protection of the territory of Sumy region is lower than recommended and averages 7.43%. Spatially, there is a band of high concentration of NPF objects with relatively large areas, which even exceeds the recommended (Konotop, Krolevets and Putivl, or according to the new zoning - Krolevets district) in the central part of the region, which is surrounded on both sides by areas with low percentage (up to 5%) of protected areas and only the extreme northern and southern parts of the region (Seredino-Budsky, Trostyanetsky, Velykopysarivsky and Okhtyrsky districts) are approaching the norm in terms of the percentage of protected areas. The patterns identified by modeling allow us to recommend increasing the share of NPF in the total area of ​​the region in two directions - increasing the area of ​​the existing facilities or creating a large number of new ones with small areas.

Tectonic inversion of the Dnieper-Donets depression and the Donbas (models and reconstructions)

For the southeastern part of the DDD and the Donbas prolongation of basin modeling to the area of late post-rift and following inverse co-folding movements has been methodically justified. Predictive analysis with recovered volume of eroded sediments has been plotted with a part of a profile Bogatoyka-Merefa as an example. Maximal values of eroded thickness are up to 1400m in the extreme southern part of the profile, the bottom of the restored volume is undulated, by the roof of the sediments of middle-late Carboniferous paleo-lifting is identified, absent in the modern section. The reconstruction conducted prolongs the border of the Early Permian basin southward. Numerical models are considered for inversion of paleo rift sedimentary basin in the rear of compressive orogene, conducted for cross-sections of the DDD and the Donbas. Specific asymmetrical distribution of the mantle deformations has been obtained which confirms displacement of folding to axial and rear (northeastern) part of flexures; the frontal zone undergoes preferably ascending movements resulting in obliquity of depression sides. In the second part of the paper the results of planned numerical modeling are given for deformations of the southern skirt of the EEP and the data of reconstructions of the stress fields of the Donbas. Comparison of model and reconstructed stress fields makes possible to confirm a conclusion of the first part of the paper. The further tectonic development of the considered area (in the late Permian?) was determined by right-hand shear displacements with small compressive component near the southern skirt of the EEP. This medium determined the formation of the right-hand shear faults of the Donbas, the growth of superimposed folding and probably its small tension. In the context of inspection of global paleo-tectonic reconstructions the studies conducted do not eliminate the probability of the Pangea “B” configuration and proceeding relative right-hand shear displacements between Eurasia and Gondwana.

Assessing the applicability of various climatic zoning methods for building construction: Case study from the extreme southern part of Chile

This study presents the results of the assessment of current climatic zoning for building construction in two regions in the extreme southern part of Chile. The simulation of heating energy consumption for a detached single-family dwelling was performed in 680 geographical locations in the study area. The dwelling, which complied with all the technical energy efficiency policies of the country, exhibited an oscillation of heating energy consumption in a range of 75–300 kWh/m2/year. The possibility of using bioclimatic zoning and zoning based on cluster analysis was assessed to determine the main parameters that might affect climatic zoning for residential buildings. The study revealed possible optimal parameters for the development of a new zoning system in the study area, namely: (i) level of heating energy consumption based on simulation in diverse geographical locations, (ii) climatic values of heating degree-days, and (iii) climatic values of direct solar radiation.

Assessment of the impacts of climatic variability and anthropogenic stress on hydrologic resilience to warming shifts in Peninsular India

Most parts of the world are witnessing climatic warming and the trend is expected to increase in the future. It is important to assess the response of watershed hydrology to this warming. Moreover, human interactions and climatic variability influence the water balance of a catchment. We perform contribution analysis along with resilience study using Budyko framework and two parameters (dynamic deviation and modified elasticity), in-order to comprehend the involvement of anthropogenic stress and climatic variance on partitioning of precipitation and their relation with hydrologic resilience to warming shifts across 55 catchments in peninsular India. Here, 23 catchments have displayed hydrologic resilience (low departure and high elasticity) to climatic warming shifts. Only 37.14% of anthropogenic dominated catchments (higher contribution from human activities in runoff changes) were found to be resilient whereas 58.82% of climate dominated catchments had resilience attributes. Most of the catchments on western and extreme southern part of India were not hydrologic resilient. Extensive human interactions tend to depart the catchment from expected hydrological functioning under critical climatic conditions (Warming in our study) that lead to declining of hydrological resilience.

Integrated Assessment of Drought Vulnerability Using Indicators for Dhasan Basin in Bundelkhand Region, Madhya Pradesh, India

The present study has integrated both spatially and temporally varying drought vulnerability factors to develop an integrated drought vulnerability map for Dhasan basin. A drought vulnerability index is used to classify the study area into different vulnerability zones. From the drought vulnerability assessment for the study area during July 2002, it was observed that the northeast, northwest and extreme southern part of the basin (20% area) was under critical vulnerability condition whereas the southwest and central part of the basin (79.9% area) was under high vulnerability condition. The critical drought vulnerability condition existed in Dhamoni, Pidaruwa, Sagar, Patharia Hat, Chhapri, Baroda Sagar and Singtoni region, whereas high vulnerability condition existed in the remaining parts of the study area. The integrated drought vulnerability approach gives superior result for drought assessment as compared to vulnerability assessment by considering the individual factors for the study area.

English

The high resolution aeromagnetic data over part of middle Benue trough was interpreted quantitatively using Spectral depth analysis and Source Parameter Imaging (SPI) of the magnetic source rocks to determine the sedimentary thickness for hydrocarbon maturation and accumulation. The study area is bounded with longitudes 09&deg;00&prime; - 10&deg;00E and Latitudes 08&deg;30&prime; - 09&deg;30&prime;N with an estimated total area of 12,100 km2. The regional/residual separation was carried out using polynomial fitting with order one. The pre-process grids dx, dy and dz from residual grid was used as an input grid to calculate the source parameter imaging. The same residual map was subdivided into nine blocks for spectral analysis. The result from source parameter imaging reveals maximum sedimentary thickness of 2.21 km at the extreme southern part of the study area which corresponds to part of Kwolla and Shendam. Minimum depth of 0.05 km is obtained at the northwestern part of the study area which corresponds to Pankshin. The result from spectral analysis also shows similar maximum depth of 2.54 km in the same area as SPI and minimum depth of 0.51 km area as SPI and minimum depth of 0.51 km. Since the sedimentary thickness of 3.0 km and above is only sufficient for hydrocarbon maturation and accumulation, then the result from this present study might not be sufficient enough for hydrocarbon maturation and accumulation but might be good for hydrocarbon gas accumulation. &nbsp; Key words: Aeromagnetic data, hydrocarbon, maturation, polynomial fitting, spectral analysis.

Spatiotemporal changes of geomorphic environment in the Muriganga–Saptamukhi estuarine interfluve of Indian Sundarban in the context of climate change: a case study

The surface of the earth has been continuously sculptured by the exogenetic processes primarily by the climatic hydrological attributes. Over the sequential phases of evolution of earth, the climatic attributes have altered. The alternative processes such as glaciation and declaciation, fluctuations of sea level and variability in rainfall pattern have changed the surface configuration through maneuvering the operations of the geographical processes. The issue of climate change has become a matter of scientific concern all over the world as the human communities are facing severe problems manifested in the form of flood, drought and submergence of low-lying coastal regions, estuaries and deltas. The present study is an attempt to understand the nature and extent of climate change (1890–2012) and related sea level rise (1970s–2010) in the deltaic Sundarban region of India since the last century and how far they are impacting the erosion–depositional processes (1925, 1926–2014). The changing trend of mean annual temperature, rainfall pattern and frequencies of tropical cyclones has been studied in detail, and spatiotemporal changes of geomorphic environment in different reaches of the study area have also been monitored with available multi-temporal geospatial data. The observation reveals that the flat sandy coastal belt and low-lying island in the extreme southern part have been severely affected by wave dash and seasonal storm surges which are mostly responsible for vigorous erosion. On the other hand, high tidal velocity is observed along the exposed concave bank in the upper–middle reaches of the Muriganga estuary and exposed outer bank in lower–middle reaches of Saptamukhi estuary. The thalweg line, which is very close to the river bank in those reaches of estuary, intensifies the hydraulic pressure along marginal parts of river bank which leads to erosion. Depositional activities are mostly observed along the sheltered inner reaches and convex river banks of the estuaries due to less effective tidal rushes, shallow channel depth, marginal flow velocity and gentle channel slope. Therefore, erosional and depositional processes cannot be explain by the relative mean sea level rise, because increasing mean sea level will affect the erosional processes uniformly in the entire estuary. In this present study area, both the erosional and depositional processes are simultaneously active depending on geographical exposure, sinuous channel pattern, channel depth and lithological compositions.

ANALYSIS OF INTERANNUAL AND SEASONAL VARIABILITY OF ICE COVER IN ANIVA BAY AND LA PEROUSE STRAIT ACCORDING TO EARTH REMOTE SENSING DATA

Based on the data of satellite observations of the ice cover with the use of geoinformation technologies, an analysis of the interannual and seasonal variability of ice cover in Aniva Bay and La Perouse Strait has been made. It is established that there is a tendency for a decrease in ice cover by 2.5% in Aniva Bay, and in La Perouse Strait – by 11% for the period from 1979 to 2016. It is revealed that Aniva Bay is the only water area with a tendency of increasing ice cover. Based on the analysis of the dynamics of ice cover anomalies relative to the climatic standard norm of 1981- 2010, periods with the predominance of its positive and negative values and years with the highest and lowest values have been marked. It is shown that the ice cover of La Perouse Strait and Aniva Bay has the greatest interrelation with the ice cover in the extreme southern part of the Sea of Okhotsk with a correlation coefficient of 0.76 and 0.66, respectively. The typing of winters according to the severity of ice conditions has been performed according to which it is determined that the sum of severe and extremely severe types of winters in Aniva Bay is higher than that in La Perouse Strait. Analysis of the intra-seasonal course of ice cover made it possible to determine the mean dates for the appearance and disappearance of the ice in Aniva Bay and La Perouse Strait, as well as the duration of the ice period. Aniva Bay is characterized by almost complete filling with ice, which occurs here in severe winters from February 10 to March 10. La Perouse Strait is filled with ice in the severe winters only by 70% - from 15 to 25 of February.

Un nuevo género y una nueva especie de eriocóccido (Homoptera: Coccinea: Eriococcidae) de Tierra del Fuego (Chile)

Se describe e ilustra Telmatococcus igniumterrae gen. nov. et sp. nov. basado en el material recolectado en una turbera de esfagno situada en el extremo sur de Sudamérica (Tierra del Fuego). El nuevo género monotípico se diferencia de los restantes géneros de Eriococcidae por tener setas cilíndricas cortas y truncadas en el aparato anal y bolsas con abudantes poros quinqueloculares cerca del aparato anal. También se describe el hábitat del nuevo taxón.

Timeline and geographical distribution of Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae: Heliothinae) in Brazil

This study presents registers of Helicoverpa armigera (Hübner) occurrence to assess its spatial and temporal distribution in Brazil. We used data from collections, especially from the Southern Region, systematic collections in Rio Grande do Sul, occasional collections of caterpillars and adults in different regions of Brazil, as well as literature registers. We conclude that the introduction of H. armigera in Brazil probably occurred before October 2008. We also register that in August 2012 H. armigera was already present from the extreme southern part (Rio Grande do Sul) to the extreme northern part (Amapá) of Brazil.

Taxonomy of the water beetle genus Limnebius Leach in southern Africa (Coleoptera: Hydraenidae)

The southern African species of the water beetle genus Limnebius Leach, 1815, are revised. Eleven new species are described, based on the examination and databasing of 6,201 specimens from 96 localities/events. Male genitalia are illustrated, and high resolution habitus images of the holotypes are provided. Distribution maps are provided for the eleven species now known from southern Africa, including Namibia, South Africa, Zambia, Zimbabwe, and the extreme southern part of Angola. New species of Limnebius are: L. capensis (South Africa: Western Cape Province, W. Cape, Hawequas); L. convexus (South Africa: Western Cape Province, Little Karroo, Raubenheimer Dam); L. endroedyi (Namibia: C. Namib desert, Numis Wasser); L. kavango (Namibia: Kavango: Mahango Game Reserve); L. masculinus (South Africa: KwaZulu-Natal Province, Hluhluwe Game Reserve); L. probus (South Africa: KwaZulu-Natal Province, Zululand, Dukuduku Forest Station); L. quantillus (South Africa: Limpopo Province, N. Transvaal, Mmabolela estate); L. retiolus (South Africa: Northern Cape Province, Cape Farm Ezelsfontein); L. speculus (South Africa: KwaZulu-Natal Province, Hluhluwe Game Reserve); L. suaviculus (South Africa: KwaZulu-Natal Province, Tugela River near Olivershoek road); L. transversus (South Africa: KwaZulu-Natal Province, Mtubatuba).

RADIOACTIVITY AND GENETIC RELATION BETWEEN THE MONZOGRANITES AND THE ENCLOSED PEGMATITES IN DAHAB AREA, SOUTHEASTERN SINAI, EGYPT

The study area lies at the southeastern part of Sinai Peninsula along the western bank of Gulf of Aqabaoccupying the extreme southern part of the Arabian- Nubian Shield. Dahab area is mainly covered byvolcanic rocks, younger gabbros, younger granites and pegmatites. The pegmatite bodies of the study areaare abundant, hosted in monzogranites and distinguished into zoned and unzoned types. They are foundas lenticular pocket and vein-like bodies. Some of these pegmatite bodies have abnormal radioactivity.Radionuclide measurements of younger granites show that their equivalent uranium content (eU) rangesbetween 6 ppm and 11 ppm, while their equivalent thorium (eTh) varies from 13 ppm to 26 ppm. Theaverage contents of U and Th of the anomalous pegmatites are 88.6 ppm and 107.9 ppm, respectivelyindicating their uraniferous nature.Geochemically, Both monzogranites and pegmatites have high K-calc alkaline characters, metaluminousand peralkaline natures, intruded in withinplate condition, derived from magma of crustal materials sourceof moderate fractionation.The Mineralogical investigations of anomalous pegmatites revealed the presence of secondary uraniummineral (autunite), in addition to thorite, uranothorite, zircon, monazite and columbite. Primary andsecondary radioactive mineralizations indicating that the mineralization is not only magmatic, but alsopost-magmatic.