The University of Asmara was a public university in Asmara, Eritrea. The nation's first university, it was founded in 1958 by the Piae Madres Nigritiae . The school was meant to provide for the local population, though its initial enrollment in the 50s was entirely Italian. Wikipedia.
McClusky S.,Massachusetts Institute of Technology |
Reilinger R.,Massachusetts Institute of Technology |
Ogubazghi G.,University of Asmara |
Amleson A.,University of Asmara |
And 7 more authors.
Geophysical Research Letters | Year: 2010
GPS measurements adjacent to the southern Red Sea and Afar Triple Junction, indicate that the Red Sea Rift bifurcates south of 17 N latitude with one branch following a continuation of the main Red Sea Rift (∼150 Az.) and the other oriented more N-S, traversing the Danakil Depression. These two rift branches account for the full Arabia-Nubia relative motion. The partitioning of extension between rift branches varies approximately linearly along strike; north of ∼16N latitude, extension (∼15 mm/yr) is all on the main Red Sea Rift while at ∼13N, extension (∼20 mm/yr) has transferred completely to the Danakil Depression. The Danakil Block separates the two rifts and rotates in a counterclockwise sense with respect to Nubia at a present-day rate of 1.9 0.1/Myr around a pole located at 17.0 0.2N, 39.7 0.2E, accommodating extension along the rifts and developing the roughly triangular geometry of the Danakil Depression. Rotating the Danakil Block back in time to close the Danakil Depression, and assuming that the rotation rate with respect to Nubia has been roughly constant, the present width of the Danakil Depression is consistent with initiation of block rotation at 9.3 4 Ma, approximately coincident with the initiation of ocean spreading in the Gulf of Aden, and a concomitant ∼70% increase in the rate of Nubia-Arabia relative motion. Copyright © 2010 by the American Geophysical Union.
ArRajehi A.,King Abdulaziz City for Science and Technology |
McClusky S.,Massachusetts Institute of Technology |
Reilinger R.,Massachusetts Institute of Technology |
Daoud M.,Syrian National Earthquake Center |
And 13 more authors.
Tectonics | Year: 2010
Five years of continuously recording GPS observations in the Kingdom of Saudi Arabia together with new continuous and survey-mode GPS observations broadly distributed across the Arabian Peninsula provide the basis for substantially improved estimates of present-day motion and internal deformation of the Arabian plate. We derive the following relative, geodetic Euler vectors (latitude (̊N), longitude (̊E), rate (̊/Myr, counterclockwise)) for Arabia-Nubia (31.7 ± 0.2, 24.6 ± 0.3, 0.37 ± 0.01), Arabia-Somalia (22.0 ± 0.5, 26.2 ± 0.5, 0.40 ± 0.01), Arabia-India (18.0 ± 3.8, 87.6 ± 3.3, 0.07 ± 0.01), Arabia-Sinai (35.7 ± 0.8, 17.1 ± 5.0, 0.15 ± 0.04), and Arabia-Eurasia (27.5 ± 0.1, 17.6 ± 0.3, 0.404 ± 0.004). We use these Euler vectors to estimate present-day stability of the Arabian plate, the rate and direction of extension across the Red Sea and Gulf of Aden, and slip rates along the southern Dead Sea fault south of the Lebanon restraining bend (4.5-4.7 ± 0.2 mm/yr, left lateral; 0.8-1.1 ± 0.3 mm/yr extension) and the Owens fracture zone (3.2-2.5 ± 0.5 mm/yr, right lateral, increasing from north to south; 1-2 mm/yr extension). On a broad scale, the Arabian plate has no resolvable internal deformation (weighted root mean square of residual motions for Arabia equals 0.6 mm/yr), although there is marginally significant evidence for N-S shortening in the Palmyride Mountains, Syria at ≤1.5 mm/yr.We show that present day Arabia plate motion with respect to Eurasia is consistent within uncertainties (i.e., ±10%) with plate tectonic estimates since the early Miocene when Arabia separated from Nubia. We estimate the time of Red Sea and Gulf of Aden rifting from present-day Arabia motion, plate tectonic evidence for a 70% increase in Arabia-Nubia relative motion at 13 Ma, and the width of the Red Sea and Gulf of Aden and find that rifting initiated roughly simultaneously (±2.2 Myr) along the strike of the Red Sea from the Gulf of Suez to the Afar Triple Junction, as well as along the West Gulf of Aden at 24 ± 2.2 Ma. Based on the present kinematics, we hypothesize that the negative buoyancy of the subducted ocean lithosphere beneath the Makran and the Zagros fold-thrust belt is the principle driver of Arabia-Eurasia convergence and that resisting forces associated with Arabia-Eurasia continental collision have had little impact on plate motion. © 2010 by the American Geophysical Union.
Fritz H.,University of Graz |
Abdelsalam M.,Oklahoma State University |
Ali K.A.,King Abdulaziz University |
Bingen B.,Geological Survey of Norway |
And 12 more authors.
Journal of African Earth Sciences | Year: 2013
The East African Orogen, extending from southern Israel, Sinai and Jordan in the north to Mozambique and Madagascar in the south, is the world́s largest Neoproterozoic to Cambrian orogenic complex. It comprises a collage of individual oceanic domains and continental fragments between the Archean Sahara-Congo-Kalahari Cratons in the west and Neoproterozoic India in the east. Orogen consolidation was achieved during distinct phases of orogeny between ~850 and 550. Ma. The northern part of the orogen, the Arabian-Nubian Shield, is predominantly juvenile Neoproterozoic crust that formed in and adjacent to the Mozambique Ocean. The ocean closed during a protracted period of island-arc and microcontinent accretion between ~850 and 620. Ma. To the south of the Arabian Nubian Shield, the Eastern Granulite-Cabo Delgado Nappe Complex of southern Kenya, Tanzania and Mozambique was an extended crust that formed adjacent to theMozambique Ocean and experienced a ~650-620. Ma granulite-facies metamorphism. Completion of the nappe assembly around 620. Ma is defined as the East African Orogeny and was related to closure of the Mozambique Ocean. Oceans persisted after 620. Ma between East Antarctica, India, southern parts of the Congo-Tanzania-Bangweulu Cratons and the Zimbabwe-Kalahari Craton. They closed during the ~600-500. Ma Kuungan or Malagasy Orogeny, a tectonothermal event that affected large portions of southern Tanzania, Zambia, Malawi, Mozambique, Madagascar and Antarctica. The East African and Kuungan Orogenies were followed by phases of post-orogenic extension. Early ~600-550. Ma extension is recorded in the Arabian-Nubian Shield and the Eastern Granulite-Cabo Delgado Nappe Complex. Later ~550-480. Ma extension affected Mozambique and southern Madagascar. Both extension phases, although diachronous,are interpreted as the result of lithospheric delamination. Along the strike of the East African Orogen, different geodynamic settings resulted in the evolution of distinctly different orogen styles. The Arabian-Nubian Shield is an accretion-type orogen comprising a stack of thin-skinned nappes resulting from the oblique convergence of bounding plates. The Eastern Granulite-Cabo Delgado Nappe Complex is interpreted as a hot- to ultra-hot orogen that evolved from a formerly extended crust. Low viscosity lower crust resisted one-sided subduction, instead a sagduction-type orogen developed. The regions of Tanzania and Madagascar affected by the Kuungan Orogeny are considered a Himalayan-type orogen composed of partly doubly thickened crust. © 2013 The Authors.
PubMed | CNRS Magmas and Volcanoes Laboratory, University of Alaska Fairbanks, Michigan Technological University, CNRS Paris Institute of Global Physics and 10 more.
Type: Journal Article | Journal: Bulletin of volcanology | Year: 2015
We present a synthesis of diverse observations of the first recorded eruption of Nabro volcano, Eritrea, which began on 12 June 2011. While no monitoring of the volcano was in effect at the time, it has been possible to reconstruct the nature and evolution of the eruption through analysis of regional seismological and infrasound data and satellite remote sensing data, supplemented by petrological analysis of erupted products and brief field surveys. The event is notable for the comparative rarity of recorded historical eruptions in the region and of caldera systems in general, for the prodigious quantity of SO
Ghinassi M.,University of Padua |
Billi P.,University of Ferrara |
Libsekal Y.,University of Asmara |
Papini M.,University of Florence |
Rook L.,University of Florence
Journal of Sedimentary Research | Year: 2013
Sedimentological and architectural data from three-dimensional larger vertical outcrops of Pleistocene fluvial deposits of the Dandiero Basin (Eritrean Danakil depression) are here used to reconstruct planform evolution of a meander bend and investigate the role of overbank flooding in sediment distribution on point bars. The point bar accumulated as part of a lowstand systems tract at the base of an incised valley cut into lacustrine mud. Selected outcrops transect a 1-km-long channel belt exposed parallel to the main fluvial transport direction. Sedimentological logs, outcrop line drawings, and paleocurrent and bedding measurements show that this outcrop belt represents a transverse section of an asymmetric fluvial point bar, which accumulated through migration of a channel 6 m deep and 70 m wide. This bar was characterized by early expansion followed by downstream accretion, which was abruptly interrupted by lacustrine deposition. The onset of downstream accretion started when the channel expanded to reach the more resistant valley wall. Sediment accreted on the downstream side of the point bar and accumulated both during bankfull discharge and overbank floods, with significant modification of the channel flow where the floodwater re-entered the main channel (i.e., riffle zone). In this zone, a secondary circulation cell triggered a shift of erosion toward the inner bank and scrolling on the downstream side of the point bar. Copyright © 2013, SEPM (Society for Sedimentary Geology).
Geochemical characteristics and Sr-Nd-Hf isotope compositions of mantle xenoliths and host basalts from Assab, Eritrea: Implications for the composition and thermal structure of the lithosphere beneath the Afar Depression
Teklay M.,University of Asmara |
Teklay M.,University of Munster |
Scherer E.E.,University of Munster |
Mezger K.,University of Munster |
Danyushevsky L.,University of Tasmania
Contributions to Mineralogy and Petrology | Year: 2010
The Afar Depression offers a rare opportunity to study the geodynamic evolution of a rift system from continental rifting to sea floor spreading. This study presents geochemical data for crustal and mantle xenoliths and their alkaline host basalts from the region. The basalts have enriched REE patterns, OIB-like trace element characteristics, and a limited range in isotopic composition (87Sr/86Sr = 0.70336-0.70356, εNd = +6.6 to +7.0, and εHf = +10.0 to +10.7). In terms of trace elements and Sr-Nd isotopes, they are similar to basalts from the Hanish and Zubair islands in the southern Red Sea and are thus interpreted to be melts from the Afar mantle. The gabbroic crustal xenoliths vary widely in isotope composition (87Sr/86Sr = 0.70437-0.70791, εNd = -8.1 to +2.5, and εHf = -10.5 to +4.9), and their trace element characteristics match those of Neoproterozoic rocks from the Arabian-Nubian Shield and modern arc rocks, suggesting that the lower crust beneath the Afar Depression contains Neoproterozoic mafic igneous rocks. Ultramafic mantle xenoliths from Assab contain primary assemblages of fresh ol + opx + cpx + sp ± pl, with no alteration or hydrous minerals. They equilibrated at 870-1,040°C and follow a steep geothermal gradient consistent with the tectonic environment of the Afar Depression. The systematic variations in major and trace elements among the Assab mantle xenoliths together with their isotopic compositions suggest that these rocks are not mantle residues but rather series of layered cumulate sills that crystallized from a relatively enriched picritic melt related to the Afar plume that was emplaced before the eruption of the host basalts. © 2009 The Author(s).
Kreuser T.,University of Asmara |
Woldu G.,University of Asmara
Special Paper of the Geological Society of America | Year: 2010
The continental glaciation of Gondwanaland in the Late Carboniferous-Early Permian left traces in many places in southern and eastern Africa. This paper focuses on the last glacial advance and consecutive deglaciation leading to the formation of large euxinic lakes with high concentrations of organic matter. The Idusi Formation in the Tanzanian Ruhuhu Basin (initiating the Karoo cycle, which extends into the Triassic) provides the type section for this depositional sequence. It is subdivided into a lower Lisimba Member, the basal unit of glacial origin, and an upper Lilangu Member, characterized by postglacial black shale and rhythmites as evidence of a climatic amelioration on a large regional scale in Africa. Thickness and facies variations are attributed to a pronounced paleotopography as the result of scouring glaciers and local tectonic events. There is a gradual change between the members, reflecting a continuous climatic amelioration and change of sediment supply. The lacustrine environment was terminated by the onset of braided stream deposition (Mpera Sandstone Member); an erosional unconformity between the units marks the start of initial rifting in the Early Permian. This is followed by the development of extensive coal swamps in a temperate climate, where organic matter predominated over clastic supply. Periglacial deposits with tillites and rhythmites, containing dropstones, are overlain by glaciolacustrine laminites intercalated with glaciofluvial marginal deltaic sediments. Deglaciation provided water and accommodation space for the evolution of extensive anaerobic stratified lakes, which were the focus of prolific deposition of organic matter. This black shale may contain up to 11% TOC (total organic carbon) content. Eventually, the lake became shallower and was succeeded by alluvial fan deposition. The duration of the glaciation and deglaciation was ∼20-25 m.y., and the lacustrine phase lasted ∼4-5 m.y. These ages have been verified by palynology (Granulatisporites confluens Oppel zone). The hydrocarbon potential of the black shale was estimated by Rock-Eval pyrolyses. Hydrogen index, maximum temperature (Tmax), and vitrinite reflection were used to determine kerogen type, maturity stage, and subsidence history. A promising potential with respect to gaseous hydrocarbon generation was detected from both the euxinic black shale and the overlying coals. A comparison with other Tanzanian Karoo basins reveals similar conditions in TOC values and temperature history. The wide regional extent of the anaerobic lacustrine black shale of the deglaciation event in several eastern and southern African basins evinces a similar climatic and regional tectonic framework in the pre-breakup phase of Gondwanaland during the Early Permian. This period of time may be of some importance in the future when the economic potential with respect to hydrocarbon generation of the Permian basins is scrutinized in more detail. © 2010 The Geological Society of America. All rights reserved.
Tesfamichael D.,University of British Columbia |
Tesfamichael D.,University of Asmara |
Pitcher T.J.,University of British Columbia |
Pauly D.,University of British Columbia
Ecology and Society | Year: 2014
The data requirements for most quantitative fishery assessment models are extensive, and most of the fisheries in the world lack time series of the required biological and socioeconomic data. Many innovative approaches have been developed to improve data collection for fisheries. We explored the use of data from fishers' interviews to estimate time series of approximate "best" catch rates. A total of 472 standardized interviews were conducted with 423 fishers along the southern Red Sea coast recording the best catch recalled and the change in average catch rates throughout the fishing career of interviewees. The results showed a decline of best catch rates in all fisheries, ranging from 4% to 10% per year for more than 50 years. The estimated rates of decline of the typical catch were higher for fishers who started fishing in recent years, suggesting that the resource base is declining, in concordance with other indicators. It is suggested that analysis of approximate data, quickly acquired at low cost from fishers through interviews, can be used to supplement other data-recording systems or used independently to document the changes that have occurred in the resource base over a lifetime of fishing. The results can be used to guide the assessment and management of resources to conserve ecosystems and livelihoods. © 2014 by the author(s).
Tewolde W.,University of Asmara
African Geographical Review | Year: 2010
Philosophy in geography at Louisiana State University This paper addresses the importance of wealth differences among the pastoralists in northwest Eritrea. Drawing upon data from a survey of 150 households, the author analyzes important economic indicators that have significant effects on production strategies of the pastoral communities. The study argues that livestock are kept as a preferred store of wealth across a wide range of social groups and therefore differentiation of livestock ownership has profound impacts on social stratification and marketing behaviour. Copyright © 2010 by the African Specialty Group of the Association of American Geographers.
Dekker T.,Swedish University of Agricultural Sciences |
Ignell R.,Swedish University of Agricultural Sciences |
Ghebru M.,University of Asmara |
Glinwood R.,Swedish University of Agricultural Sciences |
Hopkins R.,Swedish University of Agricultural Sciences
Parasites and Vectors | Year: 2011
Background: Native mosquito repellent plants have a good potential for integrated mosquito control in local settings. Ocimum forskolei, Lamiaceae, is used in Eritrea as a spatial mosquito repellent inside houses, either through crushing fresh plants or burning dry plants. We verified whether active repellent compounds could be identified using gas-chromatography coupled electroantennogram recordings (GC-EAD) with headspace extracts of crushed plants. Results: EAD active compounds included (R)-(-)-linalool, (S)-(+)-1-octen-3-ol, trans-caryophyllene, naphthalene, methyl salicylate, (R)-(-)-α-copaene, methyl cinnamate and (E)-ocimene. Of these compounds (R)-(-)-linalool, methyl cinnamate and methyl salicylate reduced landing of female Aedes aegypti on human skin-odor baited tubes. The latter two are novel mosquito repellent compounds. Conclusions: The identification of mosquito repellent compounds contributes to deciphering the mechanisms underlying repulsion, supporting the rational design of novel repellents. The three mosquito repellent compounds identified in this study are structurally dissimilar, which may indicate involvement of different sensory neurons in repulsion. Repulsion may well be enhanced through combining different repellent plants (or their synthetic mimics), and can be a locally sustainable part in mosquito control efforts. © 2011 Dekker et al; licensee BioMed Central Ltd.