The Use of Chemistry of Garnets and Heavy Minerals Around Lalago Kimberlite Pipe in Deciphering Diamond and Non-Diamond Bearing Kimberlite Pipes in Tanzania

More than three hundred kimberlite pipes have been reported in Tanzania. Only a few are diamond–bearing. A prospecting criteria to outline the diamond and non-diamond bearing kimberlites has been proposed. Bulk rock chemical analyses and chemistry of garnets and black minerals (picroilmenite, magnetite, rutile and titanite) collected around one kimberlite pipe in Tanzania were studied using Atomic Absorption Spectrophotometer (AAS) and Electron Microprobe (EMP). Although chromite and zircons occur in kimberlite pipes, they were not used in this study because they also characterize other surrounding rocks. Electron microprobe analysis of heavy minerals indicate that the ilmenites (picroilmenite) are poor in MgO contents (0.03 – 0.6 wt.%); but are rich in MnO (9.94 – 12.27wt.%). The garnets are poor in Cr2O3 with pronounced almandine content which has led to the conclusion of having a barren kimberlite source. It is suggested that combination of the chemistry of garnet and heavy minerals may be used as an exploration tool for deciphering diamond and non-diamond bearing kimberlites.Keywords: Electron microprobe, black minerals, mineral and fluid inclusions, kimberlites, garnets

The costs of introducing artemisinin-based combination therapy: evidence from district-wide implementation in rural Tanzania

BACKGROUND\ud \ud The development of antimalarial drug resistance has led to increasing calls for the introduction of artemisinin-based combination therapy (ACT). However, little evidence is available on the full costs associated with changing national malaria treatment policy. This paper presents findings on the actual drug and non-drug costs associated with deploying ACT in one district in Tanzania, and uses these data to estimate the nationwide costs of implementation in a setting where identification of malaria cases is primarily dependant on clinical diagnosis.\ud \ud METHODS\ud \ud Detailed data were collected over a three year period on the financial costs of providing ACT in Rufiji District as part of a large scale effectiveness evaluation, including costs of drugs, distribution, training, treatment guidelines and other information, education and communication (IEC) materials and publicity. The district-level costs were scaled up to estimate the costs of nationwide implementation, using four scenarios to extrapolate variable costs.\ud \ud RESULTS\ud \ud The total district costs of implementing ACT over the three year period were slightly over one million USD, with drug purchases accounting for 72.8% of this total. The composite (best) estimate of nationwide costs for the first three years of ACT implementation was 48.3 million USD (1.29 USD per capita), which varied between 21 and 67.1 million USD in the sensitivity analysis (2003 USD). In all estimates drug costs constituted the majority of total costs. However, non-drug costs such as IEC materials, drug distribution, communication, and health worker training were also substantial, accounting for 31.4% of overall ACT implementation costs in the best estimate scenario. Annual implementation costs are equivalent to 9.5% of Tanzania's recurrent health sector budget, and 28.7% of annual expenditure on medical supplies, implying a 6-fold increase in the national budget for malaria treatment.\ud \ud CONCLUSION\ud \ud The costs of implementing ACT are substantial. Although drug purchases constituted a majority of total costs, non-drug costs were also considerable. It is clear that substantial external resources will be required to facilitate and sustain effective ACT delivery across Tanzania and other malaria-endemic countries

Multiple Origins and Regional Dispersal of Resistant dhps in African Plasmodium falciparum Malaria

Cally Roper and colleagues analyze the distribution of sulfadoxine resistance mutations and flanking microsatellite loci to trace the emergence and dispersal of drug-resistant Plasmodium falciparum malaria in Africa

Lithostratigraphic and structural controls of 'tsavorite' deposits at Lemshuku, Merelani area, Tanzania

The first study of the Lemshuku 'tsavorite' mining district is presented. From bottom to top, the lithostratigraphic column corresponds to a metasedimentary sequence composed of quartzite, fine-grained graphitic gneiss, kyanite-graphite gneiss, biotite-almandine gneiss, metasomatized graphitic gneiss and dolomitic marble. 'Tsavorite' occurs in quartz veins and rarely as nodular concretions. Two factors control mineralization: (1) lithostratigraphy, with 'tsavorite' in association with pyrite and graphite confined to quartz veins within the metasomatized graphitic gneiss: and (2) structure, with the mineralized veins characteristically controlled by tight isoclinal folds associated with shearing

Evidence of evaporites in the genesis of the vanadian grossular 'tsavorite' deposit in Namalulu, Tanzania

The Namalulu tsavorite (vanadian grossular up to 0.80 wt.% V2O3) deposit in northeastern Tanzania occurs in metasomatized graphitic gneiss overlain by a dolomitic marble unit. These rocks belong to the Neoproterozoic metamorphic Mozambique Belt. The graphitic gneiss is composed of quartz, V-bearing kyanite (up to 0.4 wt.% V2O3), V-bearing muscovite (up to 1.0 wt.% V2O3), V-bearing rutile (up to 1.9 wt.% V2O3), and graphite. This rock is affected by calcic metasomatism precipitating calcite and mobilizing the elements for tsavorite crystallization in quartz-calcite veins. The dolomitic marble unit hosts an anhydrite-gypsum-dolomite lens (lens I) and a calcite-scapolite-diopside-sulfides-graphite lens (lens II). This last unit is characterized by the presence of F-bearing minerals (tremolite, phlogopite, tainiolite, titanite), with up to 9.4 wt.% F for tainiolite, and Ba-bearing minerals (feldspar, phlogopite), with up to 7.5 wt.% BaO for feldspar. Lithium (up to 2.0 wt.% Li2O) and boron (up to 110 ppm) are also present in tainiolite, as well as in F-bearing tremolite. This is the first description of metamorphic tainiolite. The protoliths of the Namalulu rocks correspond to organic-rich black shales, pure and magnesian carbonates, and evaporites. They were presumably deposited in a marine coastal sabkha located at the eastern margin of the Congo-Kalahari cratons bounded by the Mozambique Ocean during early Neoproterozoic. Tsavorite formed in the Ca-metasomatized gneiss during amphibolite facies retrograde metamorphism at 5.6-6.7 kbar and 630 ± 30 °C