Northeastern Mozambique Research Articles

Timing and origin of gold mineralization in the Neoproterozoic Xixano Complex, Mozambique Belt, northeastern Mozambique: Case study of the Nanlia and Makorongo prospects

The metallogeny of gold in northeastern Mozambique is still debated, with the main point of contention being the timing of mineralization with respect to regional tectonism, metamorphism, and magmatism. In this study, we applied Re–Os sulfide geochronology to constrain the age of gold mineralization in the Nanlia and Makorongo prospects hosted by the Xixano Complex, in the southern part of the Mozambique Belt. In addition, chemical analyses of host rocks and sulfides complement the discussion on the genesis of mineralization. Single-mineral Re–Os model ages of pyrite and pyrrhotite in quartz veins constrain the occurrence of gold mineralization in the Nanlia and Makorongo prospects between ca. 580 and ca. 560 Ma. This mineralization age interval postdated the timing of peak metamorphism of the host rocks established at ca. 631–607 Ma and is contemporaneous with the metamorphism of basement rocks between ca. 607 and ca. 564 Ma, during the thrusting of tectonic nappes in the last stage of the Pan-African orogeny. In addition, the strike of the veins in the Nanlia and Makorongo prospects is parallel to the local orientation of the thrust fault that separated the overlying rocks from the basement rocks and the dominant S1 foliation of the host rocks. These geochronological and structural data indicate a close relationship between auriferous veins in the study area and the Pan-African thrust fault associated with the emplacement of the tectonic nappes. We propose a metamorphic model for the gold mineralization in the Nanlia and Makorongo prospects, in which the mineralizing fluids were sourced mainly from dehydration of basement rocks, as a result of prograde metamorphism triggered by the juxtaposition of the Neoproterozoic tectonic nappes, including the Xixano Complex, during the last stage of the Pan-African orogeny. The mineralizing fluids ascended through the Pan-African thrust faults and structures to the overlying rocks, where the gold was deposited along the S1 foliation.

Geology and geochemistry of gold mineralization at the Namicupo prospect, Mozambique Belt, northeastern Mozambique

Auriferous quartz veins in the Namicupo gold prospect occur parallel to the foliation of metasedimentary host rocks of the Xixano Complex in northeastern Mozambique. The geochemistry and ore-forming mechanism of the Namicupo prospect have never been scientifically investigated. This study discusses the ore mineralogy, fluid inclusion, and stable isotope (S-O) characteristics of the prospect. The mineralization in the Namicupo prospect is divided into two stages. The Stage I, primary mineralization, is represented by electrum with Ag contents of 15–26 at.%, associated with pyrite and chalcopyrite. The Stage II is supergene mineralization, characterized by electrum with Ag contents of 39–46 at.%, intergrown with goethite, barite, and minium, which replaced primary sulfides. Quartz from the mineralized veins hosts three types of primary fluid inclusions coexisting in the same fluid inclusion assemblage. Type A inclusions are three-phase aqueous‑carbonic inclusions (aqueous liquid, CO2 liquid and vapor), with final homogenization temperature and salinity varying from 140 to 241 °C, and 1.0 to 7.8 wt% NaCl eq., respectively. Type B inclusions occur either as mono-phase (vapor or liquid) or two-phase (vapor and liquid) CO2-rich, N2-H2O-bearing inclusions, with homogenization temperature varying from +12.9 to +29.3 °C. The Type C inclusions are two-phase (liquid and vapor) aqueous inclusions, which homogenize to liquid phase at temperatures between 209 and 337 °C. The salinity of the Type C inclusions varies from 4.0 to 10.8 wt% NaCl eq. The sulfur isotopic ratios (δ34SCDT) of sulfides associated with Stage I mineralization and the oxygen isotopic ratios (δ18OSMOW) of water calculated from those of quartz from the quartz veins vary from −3.5 to +0.9 ‰ and −1.0 to +2.5 ‰, respectively.The primary mineralization at the prospect is classified as an orogenic-type gold mineralization, formed by aqueous‑carbonic metamorphic fluids. The precipitation of primary gold mineralization in the Namicupo prospect resulted dominantly from fluid immiscibility. The considerable amount of S up to 0.1 wt% and the high Ag contents of electrum intergrown with goethite, minium and barite suggest that the supergene mineralization in the Stage II was caused by oxidation of primary gold-bearing sulfides and Au-rich electrum under moderately acidic and oxidizing conditions, which resulted in Au and Ag liberation, likely by thiosulfate. Dissolution of primary mineralization and supergene gold enrichment in the Namicupo prospect appear to have occurred largely in situ, with little evidence of distant mobilization.

An integrated geoscience approach to effective formalization of artisanal mining in Mozambique: A case study of Namuno District, northeastern Mozambique

Mozambique's current approach for formalization of artisanal mining entails delimitating designated areas and issuing mining passes for artisanal mining within those areas. However, artisanal gold mining activities in Mozambique are more prevalent in undesignated areas than in designated areas delimitated by the central government, which impedes the effective formalization of the sector. This paper discusses the implication of geological knowledge to the formalization of artisanal gold mining in Mozambique. We present and discuss the geological characteristics and socio-economic aspects of artisanal gold mining in Namuno District, northeastern Mozambique, based on a detailed field survey in four mine sites. Artisanal mining activities in the study area focus on mainly primary orogenic-type gold mineralization associated with quartz veins, which allows for long-lived artisanal mining in the same site. The lack of geological knowledge and prioritization of large-scale resource extraction prevent an effective formalization of artisanal mining. Detailed geological characterization of the potential designated areas for artisanal mining is essential. Providing artisanal mining operators with easily understandable geological information about potential designated areas for artisanal mining, including the nature, characteristics, distribution, and extension of the mineralization, may encourage them to apply for mining passes for those areas.

Using SWAT Model and Field Data to Determine Potential of NASA-POWER Data for Modelling Rainfall-Runoff in Incalaue River Basin

Incalaue is a tributary of Lugenda River in NSR (Niassa Special Reserve) in North-Eastern Mozambique. NSR is a data-poor remote area and there is a need for rainfall-runoff data to inform decisions on water resources management, and scientific methods are needed for this wide expanse of land. This study assessed the potential of a combination of NASA-POWER (National Aeronautics and Space Administration and Prediction of Worldwide Energy Resources) remotely sensed rainfall data and FAO (Food and Agriculture Organization of the United Nations) soil and land use/cover data for modelling rainfall-runoff in Incalaue river basin. DEM (Digital Elevation Model) of 1:250,000 scale and a grid resolution of 30 m × 30 m downloaded from USGS (the United States Geological Survey) website; clipped river basin FAO digital soil and land use/cover maps; and field-collected data were used. SWAT (Soil and Water Assessment Tool) model was used to assess rainfall -runoff data generated using the NASA-POWER dataset and gauged rainfall and river flow data collected during fieldwork. FAO soil and land use/cover datasets which are globally available and widely used in the region were used for comparison with soil data collected during fieldwork. Field collected data showed that soil in the area is predominantly sandy loam and only sand content and bulk density were uniformly distributed across the soil samples. SWAT model showed a good rainfall-runoff relationship using NASA-POWER data for the area (R2 = 0.7749) for the studied period (2019-2021). There was an equally strong rainfall-runoff relationship for gauged data (R2 = 0.8131). There were uniform trends for the rainfall, temperature, and relative humidity in NASA-POWER meteorological data. Timing of peaks and lows in rainfall and river flow observed in the field and modelled were confirmed by residents as the trend in the area. This approach was used because there was no historical rainfall and river flow data since the river basin is ungauged for hydrologic data. The study showed that NASA-POWER data has the potential for use for modelling the rainfall-runoff in the basin. The difference in rainfall-runoff relationship with field-collected data could be because of landscape characteristics or topsoil layer not catered for in the FAO soil data.

Description of five new subspecies of Bebearia Hemming, 1960 and further notes on the genus (Lepidoptera: Nymphalidae, Limenetidinae, Adolaidini)

Samples of Lepidoptera of genus Bebearia Hemming, 1960 deposited in their majority in the MUHNAC collection are studied; they proceed especially from Guinea-Bissau, Angola and Mozambique. Five new subspecies are described, three from the northern Angola and one from the north-eastern Mozambique belong to the “group mardania”; a further one, from the north-western Angola, includes the “group sophus”.

Livelihood vulnerability increases human–wildlife interactions

SummaryHuman–wildlife interactions (HWIs) occur in many rural African communities, with potential impacts on livelihood vulnerability. High livelihood vulnerability may force communities to employ strategies that increase the risk of negative HWIs, yet the extent to which HWIs drive or are driven by vulnerability is unclear. We hypothesized that more vulnerable households are more likely to be exposed to wildlife and experience negative interactions. To test this hypothesis, we calculated the Livelihood Vulnerability Index (LVI) of rural households in and around Quirimbas National Park (north-eastern Mozambique) and assessed whether there is a link between livelihood vulnerability and HWIs. We found a two-way association between LVI and HWIs, with more vulnerable households indeed taking greater risks and encountering wildlife when fetching water from rivers, whereas less vulnerable households tended not to employ strategies likely to increase wildlife encounters. We also observed that HWIs exert a strong effect on livelihood vulnerability, suggesting that HWIs should be included as an exposure factor in vulnerability assessments for rural households. We recommend that livelihood strategies and community vulnerability should be considered when designing HWI mitigation schemes and implementing conservation measures.

Geological and geochemical characterization of the Nanlia and Makorongo gold prospects, Mozambique Belt, northeastern Mozambique

Northern Mozambique hosts numerous occurrences of gold mineralization in metamorphic terranes, which are little known because of the insufficient studies. In this work, we describe the main geological and geochemical characteristics of the Nanlia and Makorongo gold prospects located in the Namuno district, northeastern Mozambique. We report the mode of occurrence of gold, petrography and mineralogy of the host rocks and ores, fluid inclusion characteristics and stable isotope data, to understand the genesis of gold mineralization in the study area. The gold mineralization in the Nanlia and Makorongo prospects is hosted by the Neoproterozoic Xixano Metamorphic Complex in the Mozambique Belt, which is composed of mafic granulite, amphibolite, paragneiss and marble. The host rock amphibolite consists mainly of amphibole, plagioclase, biotite and minor quartz, titanite and sulfides. The gold mineralization is associated with E-W to ENE-WSW trending quartz veins, oriented parallel to low angle to the foliation of the host rock amphibolite. The ore mineralogy consists of pyrite, pyrrhotite, chalcopyrite, magnetite, galena and sphalerite, with minor tellurides, xilingolite, electrum and native gold. Mineralized quartz veins in the Nanlia and Makorongo prospects host two types of fluid inclusions which locally coexist in the same assemblage: type 1, one-phase CO2 inclusions with final melting temperature between −58 and −52 °C; and type 2, two-phase H2O + NaCl (±CO2 ± N2 ± CH4) inclusions with homogenization temperature ranging from 246 to 370 °C and 239 to 382 °C in the Nanlia and Makorongo prospects, respectively, and salinity of 12–21 wt% NaCl eq. Pressure and temperature (P-T) conditions of ore-formation were estimated from fluid inclusions and sphalerite geobarometry at 420–620 °C and 160–280 MPa, and 330–440 °C and 150–200 MPa in the Nanlia and Makorongo prospects, respectively. The Nanlia and Makorongo gold prospects are classified as orogenic-type gold deposits. We suggest that gold mineralization was caused by an aqueous-carbonic fluid with low-moderate salinity originated by devolatilization during prograde metamorphism of underlying rocks. The gold mineralization post-dates the peak of metamorphism of the host rocks, thus formed during the retrograde metamorphism of the host rocks. The precipitation of gold in the Nanlia and Makorongo prospects was caused by fluid phase separation induced by pressure drop as the mineralizing fluid migrated to shallower depths.

Total factor productivity and technical efficiency among smallholder groundnut farmers in Northern Mozambique

This study examines the productivity of smallholder groundnut farmers in North-eastern Mozambique using data for 2016 from two provinces with high total production of said crop. The model used is a Cobb-Douglas True Fixed Effects stochastic production frontier, controlling for geographical heterogeneity, and standard errors clustered at the village level. Our analysis reveals a mean total factor productivity index and technical efficiency score of 0.34 and 0.68 respectively. Seeding rates are found to have major potential for increasing output. This work provides new information to support ongoing efforts to generate greater resilience and robustness in domestic food systems.

<p><strong><em>Aloe</em></strong><strong> ×<em>retiefii</em> (Asphodelaceae subfam. Alooideae), a new nothospecies from northeastern South Africa, with <em>A. globuligemma</em> and <em>A. marlothii</em> as parents</strong></p>

Aloe marlothii Berger (1905: 87) (Asphodelaceae subfam. Alooideae) (Fig. 1), a single-stemmed, tree-like aloe, occurs widespread in northeastern South Africa and adjacent parts of Botswana, for example near Lobatse in the southeast of the country from where it was originally described (Fig. 2), Zimbabwe, and Mozambique (see maps in Klopper & Smith 2010: 92, Fig. 32 and Van Wyk & Smith 2014: 68). Wherever A. marlothii co-occurs with other species of Aloe Linnaeus (1753: 319), hybrids are produced (Reynolds 1950, Smith & Figueiredo 2015). Aloe globuligemma Pole-Evans (1915: 30, Plates X [Figs 1 and 2] and XI [Figs 1, 2, and 3]) (Fig. 3), a stemless, medium-sized aloe, is restricted to the more subtropical parts of northeastern South Africa, southern Zimbabwe, and Mozambique (see map in Van Wyk & Smith 2014: 158). Where these two species, A. globuligemma and A. marlothii, co-occur, for example at Lebowakgomo, about 50 km southeast of Polokwane, the capital of South Africa’s Limpopo province, a bewildering range of striking hybrids with considerable horticultural potential are found (Reynolds 1950: 446, 484, Retief 2018). This hybrid also occurs a bit further south of the Lebowakgomo location, as well as elsewhere in the Limpopo province, in Sekhukhuneland in the vicinity of Steelpoort and Ohrigstad.

Lithospheric Structure Beneath the Cretaceous Chilwa Alkaline Province (CAP) in Southern Malawi and Northeastern Mozambique

AbstractWe used aeromagnetic and satellite gravity data to investigate lithospheric structure beneath the Cretaceous Chilwa Alkaline Province (CAP) in southern Malawi and adjacent Mozambique. The CAP consists of granites, syenites, nepheline syenites, basanites, phonolite dikes, and minor carbonatite bodies. The intrusions were emplaced in the Precambrian (Mesoproterozoic‐Neoproterozoic) terranes of the Southern Irumide and Mozambique orogenic belts. Aeromagnetic data show the CAP as overlapping circular anomalies typical of nested igneous ring complexes formed through caldera collapse mechanism. We used gravity data to infer that: (1) the CAP was sourced from ~30‐km wide igneous bodies now preserved in the upper crust at ~5‐km depth. (2) the CAP is underlain by up to ~45‐km thick crust (due to mafic magmatic underplating) and a lithosphere as thin as ~90 km. These data suggest that mafic magmatic underplating and lithospheric thinning occurred during a Cretaceous rifting event. We propose, based on these results and taking into account previous petrographic, geochemical, geochronological, and isotopic studies, that the silica undersaturated magmatic phase of the CAP was due to flux melting of the asthenosphere. This was followed by silica‐rich magmatic phase due to decompression melting of the asthenosphere as a result of lithospheric thinning. Lithospheric thinning and ascendance of the asthenospheric melt might have been facilitated by the presence of late Neoproterozoic to early Cambrian suture zone. The heat provided by the mafic magmatic underplating resulted in partial melting of the lower crust to form the silica‐saturated CAP intrusions from mixed magma sources.

High-grade metamorphism during Neoproterozoic to Early Palaeozoic Gondwana assembly, exemplified from the East African Orogen of northeastern Mozambique

Northeastern Mozambique exposes a deeply eroded high-grade segment of the East African Orogen, situated at the critical intersection of the Pan-African orogenic belts, showing widespread granulite facies lithologies. This study documents and characterizes metamorphism attributed to the multistage Neoproterozoic and Early Palaeozoic events, relating to a polyphase Pan-African history of outboard nappe stacking, nappe emplacement onto Mesoproterozoic crust, and compressional and extensional deformation along the Lurio belt: 1) A Neoproterozoic nappe stack (Cabo Delgado Nappe Complex) records high-pressure granulite facies: The highest peak conditions reach P = 1.45 GPa and T > 800 °C are in Grt-Cpx-Pl-bearing mafic granulites of the Xixano Complex. A post-peak isothermal decompressional P-T evolution is supported by garnet chemical zoning pattern, pseudsection modelling and garnet corona textures. 2) The underlying Mesoproterozoic gneiss complexes record amphibolite facies to intermediate-pressure granulite facies, the high-grade metamorphism is documented by Grt-Opx-Cpx-Pl-bearing mafic granulites and charnockitic gneisses in the southern part of the Unango and Marrupa complexes. This metamorphism is attributed to crustal thickening related to overriding of the nappe complex and shortening along the Lurio belt during the early Palaeozoic Kuunga orogeny. 3) The Ocua Complex coring the Lurio belt is a locus of Early Palaeozoic high-pressure metamorphism. A minimum of P = 0.79 ± 0.13 GPa at T = 760 ± 98 °C is constrained by Grt-Opx-Cpx-Pl-Qz assemblage in mafic granulite from the western limb while high-pressure granulite metamorphism was reached in the eastern part of the complex. The high-pressure granulite facies conditions is followed by isothermal decompression.

Geochronological systematics for the Chimoio-Macossa frontal nappe in central Mozambique: Implications for the tectonic evolution of the southern part of the Mozambique belt

This work aims to acquire a better understanding of the tectonic evolution of the Mozambique Belt, for the region located in the central-western part of Mozambique that corresponds to the southernmost part of the East African Orogen, in Africa. The main objective was to make a robust geochronological study, by means of a series of U-Pb zircon ages, in order to establish some precise magmatic crystallization and/or metamorphic recrystallization ages, as well as to estimate provenance and maximum ages for meta-sedimentary units. Limited zircon Lu-Hf analyses and some Sm-Nd ages on metamorphic garnets were also obtained.Two large nappes, Macossa-Chimoio and Mungari, are envisaged in the study area, tectonically juxtaposed to the Zimbabwe Craton. The Macossa-Chimoio nappe comprises the high-grade paragneisses, granulites and migmatites characteristic of the Macossa and Chimoio Groups, which occur in close association with the pre-existent mesoproterozoic granitic rocks of the Báruè Complex. The metamorphic P-T conditions, estimated between 4 and 6 kb and 700–800 °C, and the tectonic unit was exhumed at different crustal levels. A few granitoids of the Báruè Complex yielded mesoproterozoic U-Pb zircon cristallyzation ages near 1100 M, but detrital zircons of some paragneisses yielded neoproterozoic maximum ages of deposition of 700–800 Ma. In addition, the main age of the very young cambrian metamorphism event was set by means of U-Pb dating of zircon overgrowths and Sm-Nd garnet-whole rock isochron at 500 Ma.The boundary between the Macossa-Chimoio and Mungari nappes is a thrust zone with a NW trending tectonic transport. It disappears to the NE below a Karoo sedimentary cover, but most likely reappears at the NE side of the basin as a prolongation of a long-lived tectonic boundary, the Lurio mega-shear belt of northeastern Mozambique which separates the Nampula tectonic block in the south from a northern block comprising the Marrupa and Unango complexes. Therefore, the Macossa-Chimoio Nappe would correlate closely with the Nampula Block, which includes mesoproterozóic orthogneisses with about 1100 Ma age, reactivated in the Cambrian.On the light of the U-Pb ages of overgrowth rims on zircon crystals and corroborative Sm-Nd isochron ages, the southern end of the Mozambique Belt in Africa was affected by a strong orogenic episode in the Cambrian. This confirms that the amalgamation of Gondwana was diachronous along the EAO, starting earlier in the north and cease later in the south. In the south, the orogenic event was coeval to the Kuunga Orogeny between Australia and Antarctica, usually constrained between 530 and 490 Ma.

Zircon U-Pb age constraints for Tonian-early Cryogenian deposition of metasedimentary rocks from the Schirmacher Oasis, East Antarctica: Implications for correlations across the Mozambique Ocean

Schirmacher Oasis, central Dronning Maud Land, East Antarctica, a dispersed fragment of the 660-610 Ma East African Orogen (EAO), exposes platformal-facies high-grade metasedimentary rocks. Here we constrain the depositional age of these sedimentary rocks to test models relating to timing of the closure of the Mozambique Ocean, the southern segment of the EAO, since Tonian time. Zircon, a proxy for detritus, was dated by LA-MC-ICPMS (206Pb/238U ages) that includes both magmatic and (older) metamorphic populations, in addition to those formed during the granulite-facies metamorphic events (660-600 Ma and 580-555 Ma) having an age range between 1240 and 500 Ma. In conjunction with field evidence, their depositional time is constrained to the Neoproterozoic (Tonian to early Cryogenian, i.e. 1000 >Tdep >800 Ma and 930 >Tdep>800 Ma) with their provenance likely dominated by metamorphic (orogenic) over magmatic rocks.These metacarbonate and psammitic rocks are correlated with similar rocks from the Montepuetz Complex, Northeastern Mozambique, metacarbonate rocks from the Sør Rondane Mountains and with the Linta Group, Vohibory Domain, Southeastern Madagascar. The coeval deposition of platformal sedimentary protoliths, interpreted as occurrence of multiple Mozambique Oceanic strands, were incorporated into the continental arc crust during collision between the Congo and Azania cratonic blocks forming the EAO.

A new species of tree, Icuria dunensis (Icurri), of undescribed coastal forests in north-eastern Mozambique

A new species of tree, Icuria dunensis (Icurri), of undescribed coastal forests in north-eastern Mozambique

Petrochemistry, Mineral Chemistry, and Pressure–Temperature Model of Corundum-Bearing Amphibolite from Montepuez, Mozambique

Montepuez corundum deposits in the northeastern Mozambique are geologically linked to parts of Neoproterozoic Mozambique Belt collectively described as the Montepuez Complex, containing high-grade metamorphic rocks, belonging to amphibolite facies and including corundum-bearing and corundum-barren amphibolites. Corundum-bearing amphibolites contain pargasite, spinel, and anorthite with minor amounts of corundum and secondary altered rock types containing significant mica and clay minerals. The corundum-barren amphibolites are dominated by pargasite, anorthite, and spinel. Geochemical analyses indicate that the amphibolites probably originated from basaltic protoliths associated with subduction-related arc magmatism. Phase equilibrium modeling in the system $$\hbox {Na}_{2}\hbox {O}{-}\hbox {MgO}{-}\hbox {MnO}{-}\hbox {Al}_{2}\hbox {O}_{3}{-}\hbox {SiO}_{2}{-}\hbox {CaO}{-} \hbox {FeO}{-}\hbox {H}_{2}\hbox {O}$$ in combination with mineral isopleths indicate pressure–temperature (P–T) conditions of about 10–11.5 kbar and 450– $$600\,^{\circ }\hbox {C}$$ , lower than those recorded for the Eastern Granulite of the Mozambique Belt that extends northward to Kenya and Tanzania as part of the Pan-African orogen. Therefore, metamorphic P–T condition increased northward, suggesting different levels of crustal thickening of NE Mozambique compared with Tanzania and Kenya.

A new Reed Frog (Hyperoliidae: Hyperolius) from coastal northeastern Mozambique.

A new species of African reed frog (genus Hyperolius Rapp, 1842) is described from the Coastal Forests of the Eastern Africa Biodiversity Hotspot in northeastern Mozambique. It is currently only known from less than ten localities associated with the Mozambican coastal pans system, but may also occur in the southeastern corner of Tanzania. Phylogenetic reconstructions using the mitochondrial 16S marker revealed that it is the sister taxon of Hyperolius mitchelli (>5.6% 16S mtDNA sequence divergence) and forms part of a larger H. mitchelli complex with H. mitchelli and H. rubrovermiculatus. The new species is distinguished from other closely related Hyperolius species by genetic divergence, morphology, vocalisation, and dorsal colouration.

A new species of Scolecoseps (Reptilia: Scincidae) from coastal north-eastern Mozambique

ABSTRACTSeven specimens of Scolecoseps Loveridge, 1920 from the vicinity of Palma on the north coast of Mozambique are compared morphologically with other known material of this genus. The new material can be distinguished morphologically from all other Scolecoseps by the presence and position of certain head scales, particularly a supraciliary and four small suboculars, a small mental and high subcaudal counts. It is described as a new species, Scolecoseps broadleyi sp. nov. The new species is found in coastal savannah habitat under leaf litter of Berlinia orientalis trees, in sandy soils in close proximity to large wetlands. Its currently known distribution is south of the range of Scolecoseps litipoensis Broadley, 1995 and north of that of Scolecoseps boulengeri Loveridge, 1920. We provide a review of the available literature for the genus Scolecoseps and highlight the necessity for additional research on these poorly known fossorial skinks.ZooBank— Scolecoseps broadleyi: urn:lsid:zoobank.org:act:C4E3723C-F982-4CFA-900B-0B23A9AD5B84

A review ofEuphorbia mlanjeanaL.C.Leach (Euphorbiaceae): its habitats on Mount Mulanje (Malawi) and new localities in Mozambique

A broad review of the history, discovery, characteristics, distribution, habitats and relationships of the shrubby Euphorbia mlanjeana is provided. On Mt. Mulanje (Malawi) where it was hitherto listed as endemic to mountain and country, E. mlanjeana occurs in four populations occupying similar habitats and sharing similar habitat conditions on granitic rocks: two foothill populations (The Crater and Ruo Gorge), one along the upper Likhubula/Lichenya path, and the highest-lying one on the Lichenya plateau. The trunk height and the length of the branches decreases with increasing altitude, which is related to the increasingly unfavourable climatic conditions. Recent molecular data (Bruyns et al., 2011) show E. mlanjeana to be closest to two other shrubby species (E. knuthii and E. waterbergensis) which are all three placed amongst arborescent species, suggesting that the shrubby habit may have evolved from arborescent ancestors. In addition, three localities in northeastern Mozambique recently discovered by P. V. Bruyns are reported, so that E. mlanjeana is no longer an endemic of Mt. Mulanje and can be enlisted for the Flora of Mozambique.

New insights into the origin of the Evate apatite-iron oxide-carbonate deposit, Northeastern Mozambique, constrained by mineralogy, textures, thermochronometry, and fluid inclusions

The Evate deposit represents the largest resource of apatite in south-east Africa (155 Mt. ore grading 9.3wt.% P2O5) accumulated in up to 100m thick magnetite-carbonate-apatite horizons conformable to the granulitic gneiss of the Monapo Klippe. Baddeleyite and zircon from early iron-oxide (magnetite, geikielite, spinel), apatite- and forsterite-bearing rocks have been dated to 590±6Ma using the LA-ICPMS U-Pb method, whereas monazites from anhydrite-apatite-carbonate rocks show a concordant U-Pb-Th age corresponding to 449±2Ma. Temperatures inferred from calcite-dolomite solvus data and graphite structural ordering span the interval from ≥815 to 276°C. Primary and secondary fluid inclusions in apatite document calciocarbonatite melts associated with early apatite, and CO2-bearing sulfate-chloride brines progressively diluted with low-salinity, probably metoric waters, towards ultimate stages of the deposit formation. The calciocarbonatite melts have initially coexisted with liquid nitrogen and later with sulfate-chloride brines mixed with N2±CO2 gas.Crystallization of spinel around baddeleyite by the mechanism of Ostwald ripening, nucleation of graphite spherules along pyrrhotite-carbonate boundaries, the occurrence of molybdenite, baddeleyite-to-zircon transformation, and high crystallization temperatures inferred from graphite structural ordering and calcite-dolomite thermometry suggest a magmatic origin of the early mineral assemblages. In contrast, microthermometric characteristics of primary aqueous inclusions in the late apatite and the presence of zeolites (thomsonite-Ca, mezolite) is diagnostic of a low-temperature hydrothermal crystallization.Formation of the early magnetite-apatite-forsterite assemblage is thought to be coeval with mafic alkalic intrusions of the Mazerapane Suite superimposed on the granulite facies metamorphism of the Monapo Klippe. The low-temperature, anhydrite-bearing mineralization was associated with the massive circulation of sulfate-rich brines along fractures activated during the Late Cambrian-Ordovician extension. Origin of the sulfate-rich brines may be genetically related either with the magmatic-hydrothermal differentiation, or with the remobilization of crustal evaporites.

A new species of Zygaspis (Reptilia: Squamata: Amphisbaenidae) from north-eastern Mozambique

We describe a new species of Zygaspis based on a single specimen collected in north-eastern Mozambique and deposited in the Natural History Museum of Zimbabwe, Bulawayo. The new species is characterised by its extensively black pigmentation, 191 body annuli, discrete preoculars, four parietals, two postoculars, three supralabials, and two post-supralabials. Phylogenetic analysis of mtDNA suggests that it is a sister taxon to the widespread Zygaspis quadrifrons.ZooBank.—urn:lsid:zoobank.org:pub:9651A65E-949E-4C95-A363-81C558A222AC