Peninsular India forms a keystone in Gondwana, linking the East African and Malagasy orogens with Ediacaran–Cambrian orogenic belts in Sri Lanka and the Lützow Holm Bay region of Antarctica with ...similar aged belts in Mozambique, Malawi and Zambia. Ediacaran–Cambrian metamorphism and deformation in the Southern Granulite Terrane (SGT) reflect the past tectonic setting of this region as the leading vertex of Neoproterozoic India as it collided with Azania, the Congo–Tanzania–Bangweulu Block and Kalahari on one side and the Australia/Mawson continent on the other. The high-grade terranes of southern India are made up of four main tectonic units; from north to south these are a) the Salem Block, b) the Madurai Block, c) the Trivandrum Block, and d) the Nagercoil Block. The Salem Block is essentially the metamorphosed Dharwar craton and is bound to the south by the Palghat-Cauvery shear system — here interpreted as a terrane boundary and the Mozambique Ocean suture. The Madurai Block is interpreted as a continuation of the Antananarivo Block (and overlying Palaeoproterozoic sedimentary sequence — the Itremo Group) of Madagascar and a part of the Neoproterozoic microcontinent Azania. The boundary between this and the Trivandrum Block is the Achankovil Zone, that here is not interpreted as a terrane boundary, but may represent an Ediacaran rift zone reactivated in latest Ediacaran–Cambrian times.
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► Southern Granulite Terrane of South India consists of Proterozoic terranes exotic to India. ► The Madurai Block is the southern extent of the Neoproterozoic continent Azania. ► Metasediments in the Madurai and Trivandrum Blocks have provenance from Africa. ► The Achankovil Zone and Southern Madurai Block consist of Neoproterozoic metasediments.
La pneumocystose pulmonaire est une des plus fréquentes infections opportunistes au cours de l'infection à VIH. Notre étude consiste à décrire les aspects épidémio-cliniques de la pneumocystose ...pulmonaire vus au Service de Maladies Infectieuses du CHU JRB. Il s'agit d'une étude rétrospective, descriptive menée pendant la période du 1er janvier au 31 décembre 2015. Nous avons colligé 34 cas de pneumocystose pulmonaire, avec une prévalence de 29,57%. L'âge moyen était de 39,7 ans. On notait une prédominance masculine avec un sex ratio de 2,90. Les signes révélateurs étaient classiques, dominés par la fièvre, la toux et la dyspnée. Le diagnostic de certitude n'a été obtenu que dans 2,95% des cas, sachant qu'un seul patient avait bénéficié d'un examen du LBA et que 26,46% des patients ont effectué un examen mycologique des crachats induits. L'évolution était favorable dans 73,53% des cas et nous avons déploré 29,59% de décès. Le diagnostic de certitude de la pneumocystose pulmonaire est difficilement accessible au Service de Maladies Infectieuses du CHU-JRB. La facilitation de l'accès aux moyens de diagnostic pourrait mener au diagnostic de certitude et améliorer ainsi la survie des patients.
•Tectonic restoration of Archean Western Dharwar Craton (WDC), west coast, India.•Craton-limiting mid-crustal Paleoproterozoic transpressional orogens delineated.•2.3–2.5Ga WDC-Coorg Block accretion ...extends as <2.5Ga Betsimisaraka suture.•Northern Craton-limiting orogen extends into Madagascar as buried tectonic zone.•No evidence of Mesoproterozoic and younger accretion/tectonism within WDC.
New structural–mineralogical data and U–Th-total Pb monazite chemical ages in 27 samples in a 430km long corridor along the west coast of India are combined with existing data to reconstruct the tectonic set up of the Meso/Neoarchean crystalline rocks in the Western Dharwar Craton (WDC). The data helps to delineate two NW-trending Paleoproterozoic ductile shear zones that limit the southern and the northern margins of the WDC. The southern shear zone (metamorphic age: 2.3–2.4Ga) separates the greenschist facies supracrustal belts (2.5 and 3.3Ga), foliated granitoids (2.5 and 2.9Ga) and amphibolite facies anatectic gneisses (>3.0Ga) of the WDC from the >2.9Ga granulite facies ortho/para-gneisses of the Coorg Block. This shear zone is correlated with the ∼2.4Ga Betsimisaraka suture zone in east-central Madagascar that demarcates the accretion zone between the Antongil Block (≈WDC) and the granulite facies lithologies of the Antananarivo domain (≈Coorg Block). The northern shear zone system (metamorphic age: 2.2–1.8Ga) extending NW into Madagascar possibly exists as a hitherto undiscovered tectonic zone forming the basement of the Mesoproterozoic Sahantaha Formation underlying the Neoproterozoic Bemarivo Belt supracrustals in NE Madagascar.
Within the WDC, the Meso/Neoproterozoic ages retrieved from poorly-defined margins in monazite are uncommon, dispersed within the craton, and do not define localized zones within the craton. The chemical ages of metamorphic monazites formed at greenschist/amphibolite facies conditions preclude metamorphism–deformation associated with accretion of crustal blocks within the WDC during the Rodinia assembly.
Over the last few years, many inhabitants of Madagascar's capital city Antananarivo have started to perceive an increase in insecurity, crime, and violence. By the evening, people lock themselves in ...their houses out of fear of robbery and assault. Many urban dwellers blame this insecurity on organized criminal groups coming from the poorest neighborhoods of the capital-neighborhoods inhabited mainly by migrants from other regions of the island and by slave descendants. By investigating the local dynamics of economic and social marginalization that slave descendants and migrants experience and by exploring the growing "fear of the dark" perceived by people belonging to different status groups, this paper demonstrates how memories of slavery are still deeply inscribed in the social geography of Antananarivo. It traces how the legacies of slavery are reshaped in an urban context where social divisions between status groups still permeate local representations of poverty and insecurity.
Metropolitan and suburban areas in Africa are rapidly expanding with, in general, a poor safe urban management. Urban development in zones not suitable for construction leads to significant economic ...loss. The aggregate building damage combined with other environmental treats like drought, flooding or landsliding are enhancing African city vulnerability. Simple cartographic products made available to the general public could facilitate the first stage of planning and management considering parameters that affect building foundation. We combine here in ARCGIS geological, geomorphological and geotechnical data to provide such a framework focusing on the capital city of Antananarivo in Madagascar. The city was initially constructed on basement hills covered with a thick loose weathered layer and is expanding into the alluvial lowland watered by the Ikopa River. About 221 boreholes with pressumeters and laboratory data provide a picture of the underground characteristics, and allow the computation of the soil bearing capacity, the key parameter we used to assess building suitability. Lithology, slope, land-use and ground water level are combine to build a first geotechnical map that is completed using a mapping of the soil bearing capacity combined with land-use and geohydrological constraints. The geotechnical maps divide the city into zones with different constructive conditions that can be use as a first tool for urban development planning.
•Mapping based on geomechanical properties of the underground.•GIS geotechnical mapping for a safer city extension.
Regurgitated pellets from the Olive Bee-eater, Merops superciliosus, were collected below a hunting perch in Antananarivo, Madagascar, and used to examine this species' food habits. The diet of this ...species was largely composed of bees (Apidae, genus Apis) and the next most common group was wasps (Vespidae). Remains of soft-bodied ticks (Argasidae) were also identified, presumably associated with the consumption of ectoparasites during preening.
Large uncertainties still exist about the long-term mechanisms influencing the hydroclimate variability of southeast Africa where proxy data and model simulations indicate rainfall dipoles between ...subtropical and tropical areas. The topography of Madagascar, located off the southeastern coast of Africa, modulates these dipoles while its climate is influenced by the position of the Intertropical Convergence Zone (ITCZ) and the Subtropical High as well as the sea surface temperature (SST) of SW Indian Ocean. The island can thus be considered a key location for the understanding of the tropical SE African climatic variability and the interplay between atmospheric patterns. However, the scarcity of continuous records from Madagascar has made the evolution of regional late Quaternary climate and its driving mechanisms difficult to assess. Here, we present a 26-kyr record of the deuterium/hydrogen isotope ratio (δD) of biomarkers (n-alkanes) from the central eastern part of the island at Antananarivo at around 1250 m a.s.l. Preliminary summary pollen data are also presented as a comparison. The δD profiles of aquatic plant and terrestrial plant-derived n-alkanes generally exhibit similar trends implying that they all record changes in the isotope composition of source water, namely meteoric water that recharges soil and lake waters. In this tropical region, the δD variability of precipitation is mainly influenced by the amount effect reflecting the intensity of precipitation associated with the monsoon. We observe: (i) stable and wet conditions during the Last Glacial Maximum, (ii) drier conditions from 18.5 to 15 ka (ka before present) during the Heinrich Stadial 1 (iii) high humidity after 15 ka culminating at the Younger Dryas (YD), (iv) drier conditions from 11.7 ka to 8.2 ka, (v) a return to humid climate until 2.8 ka, and (vi) an arid phase followed by increased wetness after 0.9 ka, although the record is likely influenced by human-induced vegetation changes the last 1.2 ka. This climate signal is similar to other records from the Mozambique Channel but opposite to records from the East African mainland and the subtropical southern Africa, especially between 20 and 25°S. Although there is a good correspondence of our record with insolation- driven migrations of ITCZ during the LGM and the early Holocene, the dipoles are largely consistent with the modern rainfall anomaly and are best explained by the interlinked effects of the SST changes and the variability of the Mozambique Channel Trough.
•A 26000-year paleoclimatic record from the Central Highlands of Madagascar.•Our leaf-wax δD reflects the intensity of precipitation associated with the monsoon.•Wet Last Glacial Maximum, Younger Dryas, mid-Holocene and dry early, late Holocene.•Opposite signal to the tropical East African mainland and SE Africa 20So-25oS.•This variability is driven by the intensity of Mozambique Channel Trough.
Abstract
Background
Anaemia occurs in children when the haemoglobin level in the blood is less than the normal (11 g/dL), the consequence is the decrease of oxygen quantity in the tissues. It is a ...prevalent public health problem in many low-income countries, including Madagascar, and data on risk factors are lacking. We used existing data collected within the pathophysiology of environmental enteric dysfunction (EED) in Madagascar and the Central African Republic project (AFRIBIOTA project) conducted in underprivileged neighbourhoods of Antananarivo to investigate the factors associated with anaemia in children 24 to 59 months of age.
Methods
Children included in the AFRIBIOTA project in Antananarivo for whom data on haemoglobin and ferritin concentrations were available were included in the study. Logistic regression modelling was performed to identify factors associated with anaemia.
Results
Of the 414 children included in this data analysis, 24.4% were found to suffer from anaemia. We found that older children (adjusted OR: 0.95; 95% CI: 0.93–0.98) were less likely to have anaemia. Those with iron deficiency (adjusted OR: 6.1; 95% CI: 3.4–11.1) and those with a high level of faecal calprotectin (adjusted OR: 2.5; 95% CI: 1.4–4.4) were more likely to have anaemia than controls.
Conclusions
To reduce anaemia in the children in this underprivileged area, more emphasis should be given to national strategies that improve children’s dietary quality and micronutrient intake. Furthermore, existing measures should be broadened to include measures to reduce infectious disease burden.
•Summary of U–Pb geochronology of the Precambrian shield in Madagascar.•Nullification of the “Betsimisaraka Suture”.•The Greater Dharwar Craton and its southern Paleoproterozoic continent ...(SMIWH).•Review of Stenian–Tonian and Cryogenian- Ediacaran igneous rocks in Madagascar.•Ediacaran- Early Cambrian orogenic history of Madagascar and Gondwana.
Available U–Pb geochronology of the Precambrian shield of Madagascar is summarized and integrated into a synthesis of the region’s geological history. The shield is described in terms of six geodynamic domains, from northeast to southwest, the Bemarivo, Antongil–Masora, Antananarivo, Ikalamavony, Androyan–Anosyan, and Vohibory domains. Each domain is defined by distinctive suites of metaigneous rocks and metasedimentary groups, and a unique history of Archean (∼2.5Ga) and Proterozoic (∼1.0Ga, ∼0.80Ga, and ∼0.55Ga) reworking. Superimposed within and across these domains are scores of Neoproterozoic granitic stocks and batholiths as well as kilometer long zones of steeply dipping, highly strained rocks that record the effects of Gondwana’s amalgamation and shortening in latest Neoproterozoic time (0.560–0.520Ga).
The present-day shield of Madagascar is best viewed as part of the Greater Dharwar Craton, of Archean age, to which three exotic terranes were added in Proterozoic time. The domains in Madagascar representing the Greater Dharwar Craton include the Antongil–Masora domain, a fragment of the Western Dharwar of India, and the Neoarchean Antananarivo domain (with its Tsaratanana Complex) which is broadly analogous to the Eastern Dharwar of India. In its reconstructed position, the Greater Dharwar Craton consists of a central nucleus of Paleo-Mesoarchean age (>3.1Ga), the combined Western Dharwar and Antongil–Masora domain, flanked by mostly juvenile “granite–greenstone belts” of Neoarchean age (2.70–2.56Ga). The age of the accretionary event that formed this craton is approximately 2.5–2.45Ga. The three domains in Madagascar exotic to the Greater Dharwar Craton are the Androyan–Anosyan, Vohibory, and Bemarivo. The basement to the Androyan–Anosyan domain is a continental terrane of Paleoproterozoic age (2.0–1.78Ga) that was accreted to the southern margin (present-day direction) of the Greater Dharwar Craton in pre-Stratherian time (>1.6Ga), and rejuvenated at 1.03–0.93Ga with the creation of the Ikalamavony domain. The Vohibory domain, an oceanic terrane of Neoproterozoic age was accreted to the Androyan–Anosyan domain in Cryogenian time (∼0.63–0.60Ga). The Bemarivo domain of north Madagascar is a terrane of Cryogenian igneous rocks, with a cryptic Paleoproterozoic basement, that was accreted to the Greater Dharwar Craton in latest Ediacaran to earliest Cambrian time (0.53–0.51Ga).
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