Using perovskite to determine the pre-shallow level contamination magma characteristics of kimberlite

It remains difficult to obtain reliable geochemical signatures of uncontaminated kimberlite magma from bulk rock studies due to the combined effects of crustal assimilation and element mobility during post-emplacement alteration processes. Groundmass perovskite (CaTiO3), a typical accessory phase, from Orapa (Botswana) and Wesselton (South Africa) kimberlites has been used to evaluate the isotope and trace element composition of the pre-contamination magmas and the effects of shallow level contamination. In-situ trace element signatures of Orapa and Wesselton perovskite grains are broadly similar and unaffected by crustal contamination. Single grain Sr-87/Sr-86 isotope ratios of perovskite from Orapa (0.7030-0.7036) are less scattered than bulk rock analyses (0.7063-0.7156), which are variably affected by contamination and late stage alteration. Initial Sr-87/Sr-86 isotope ratios of perovskite (0.7044-0.7049) from Wesselton overlap with published whole rock studies on fresh hypabyssal kimberlites (0.7042-0.7047). The limited intra-kimberlite variation in Sr isotope ratios recorded by the perovskite are unlikely to be due to crustal contamination as the calculated liquid compositions in equilibrium with the perovskite analysed typically have &gt;1500 ppmSr, and most common crustal lithologies underlying these kimberlites have relatively low Sr contents and are not highly radiogenic. Calculated pre-shallow level contamination magma compositions for Orapa and Wesselton have significantly fractionated LREE and highly variable non-smooth trace element patterns. Initial Sr and Nd isotope ratios of both kimberlites fall on the mantle Nd-Sr array with enriched Sr and slightly depleted Nd signatures, similar to Group I kimberlites. Overall, the trace element and isotopic composition of Orapa and Wesselton kimberlites are similar to the reported Group I kimberlites from southern Africa, which are derived by very low degrees of partial melting from a LREE depleted metasomatised sub-continental lithospheric mantle (SCLM) source. (C) 2013 Elsevier B.V. All rights reserved.</p

Chromolaena in the Asia-Pacific region Proceedings of the 6th International Workshop on biological control and management of chromolaena held in Cairns, Australia, May 6–9, 2003

Crop Production/Industries,

Cretaceous fossils from the Orapa Diamond Mine

Main articleThe Orapa kimberlite pipe, situated in north-central Botswana, is well-known for its rich reserves of diamonds. It is indeed one of the largest and richest diamond mines in the world. The kimberlite magma transporting the diamonds from the upper mantle erupted through a sequence ofKaroo-aged rocks before the deposition ofthe Kalahari Sands. This eruption has been radiometrically dated at early Late Cretaceous (Cenomanian-Coniacian). When volcanism ceased, a succession of epiclastic crater lake sediments was deposited above the kimberlite plug. Analysis of these sediments, which mostly comprise the results of mudflows and debris flows and fmer sediments during quiescenttimes, suggests that most of the sediments within the crater were deposited rapidly as mass flows, and were therefore mobilised soon after the volcanic eruption. Buried within the fine-grained sediments is a unique assemblage of fossils including flowering plants and many whole-bodied insects. The fossils are commonly exquisitely preserved in extremely fine-grained mudstone. Interpretation of the sedimentary facies and fossils is that the mid-Cretaceous climate of central Botswana was temperate, seasonal and wet, and the area surrounding the crater was forested. The fossils represent the recovery of the biota of the area after the violent eruptions of Orapa and other nearby kimberlite fissures and pipes. The fossils have contributed considerably to our understanding of mid-Cretaceous insects and flowering plants and suggest intimate relationships between the two at an early stage in the radiation of flowering plants. It seems that southern Gondwana (including southern Africa) was a centre of diversification for both insects and angiosperms in the mid-Cretaceous.Friends of the Museum, Gaborone; Debswana (Orapa); University of the Witwatersrand; South African Foundation for Research Developmen

The invasive shrub Piper aduncum in Papua New Guinea: a review

HARTEMINK AE. 2010. The invasive shrub Piper aduneum in Papua New Guinea: a review. Piper aduncum is a shrub native to Central America. It is found in most Central and South American countries and also in the Caribbean and southern Florida (USA). In Asia and the Pacific, P aduncum occurs in Indonesia, Malaysia, Philippines, Papua New Guinea, Solomon Islands, Vanuatu, Fiji, Micronesia, American Samoa, Niue, the Marianas, Tonga, Samoa, the Cook Islands, Palatt and Hawaii (USA). Piper aduncum arrived in Papua New Guinea before the mid-1930s. From the 1970s, it started to dominate the secondary fallow vegetation in many parts of the humid lowlands. It invaded grassland areas and also appeared in the highlands up to 2100 in asl. The seeds are dispersed by birds, bats and wind, as well as by logging equipment and in some localities, by migrating people. The combination of its vigorous generative characteristics (small and abundant seeds), high growth rate and the accidental or intentional spreading has resulted ill its presence in most provinces of Papua New Guinea. In the 1990s, awareness of the spread of P aduncum grew and there was a corresponding increase in research interest. from a range of disciplines, e.g. pharmacology, agronomy, quarantine, forestry and taxonomy. The invasion of P aduncum has affected the farming system and livelihood of many rural people. Future research should focus on mapping its extent, and studying its agronomic, socio-economic and ecological effects, particularly its effect on biodiversity

Innovative Corporate Social Responsibility in Botswana: The Debswana Mining Company Study Case

This paper presents a study case on innovative corporate social responsibility as a very important aspect of management planning and, in the process, explores some trends and new ideas pertaining to corporate social responsibility in mining industries. Some pertinent literature is reviewed as a theoretical frame to introduce the presentation of the Debswana Mining Company case to show innovative corporate social responsibility in the mining industries in Botswana

Biocontrol of Chromolaena odorata in Papua New Guinea

Chromolaena odorata (L.) King and Robinson (Asteraceae) is a significant agricultural weed in Papua New Guinea (PNG), affecting plantations, food gardens and grazing lands. It was the focus of a collaborative biocontrol program funded by the Australian Government between 1998 and 2007. Chromolaena was recorded at 680 sites in 13 provinces of PNG through surveys, field releases of biocontrol agents and feedback from public awareness programs. Three biocontrol agents, the moth Pareuchaetes pseudoinsulata Rego Barros (Lepidoptera: Arctiidae), the stemgalling fly Cecidochares connexa (Macquart) (Diptera: Tephritidae) and the leaf mining fly Calycomyza eupatorivora Spencer (Diptera: Agromyzidae), were introduced to control chromolaena. Cecidochares connexa was found to be the most effective of the agents introduced as it quickly established at over 300 sites where it was released and spread up to 100km in five years from some sites. Experimental field plots established to determine the impact of the agents on chromolaena, showed that the size of chromolaena infestations decreased with the presence of C. connexa. A survey was conducted to quantify the social and economic benefits of biocontrol of chromolaena to landholders. Chromolaena is considered to be under substantial/significant control in nine provinces in PNG, with about 50% of respondents stating that there is less than 50% of chromolaena remaining following the release of the gall fly. This has resulted in landholders spending less time clearing chromolaena and the re-establishment of small-scale subsistence farms and the regeneration of natural vegetation. Crop yield and income generated from the sale of agricultural produce have increased by at least 50% since chromolaena was brought under biocontrol. It is anticipated that the gall fly will continue to spread and control chromolaena in areas where it has not yet reached, thereby further reducing the impact of the weed in PNG

Triple Wins from Foreign Direct Investment: Potential for Commonwealth countries to maximise economic and community benefits from inward investments case studies of Belize and Botswana

The findings of the case study on Botswana indicate that mining companies in Botswana have adopted the philosophy of CSR and are prepared to link social and environmental initiates to their core business. Particularly impressive is the comprehensive approach taken by the diamond mining company Setswana to develop and decentralise its strategy on Corporate Social Investment. In so doing, the company demonstrated preparedness to go beyond business as usual' approach of merely creating jobs and provide Foreign Direct Investment (FDI)

A method of improving contrast in illustrations of coalified fossils

A simple, economic method of enhancing the contrast and, therefore, improving the qual ity of certain palaeontological photographic illustrations is outlined. The technique, which involves the use of polarising filters, in no way alters the negatives or prints. In recommending this technique, it is hoped some of the confusion arising from inadequate illustrations will be removed.F.R.

Boletín oficial de la provincia de León: Num. 170 (01/08/1945)

Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2011-201