Characteristics of B,Zn and Se in stream sediments of Tanzania and their agricultural applications:Based on 1∶1000000 geochemical survey

Tanzania is located in eastern Africa with a predominantly agricultural ecomomy,the potential for developing and utilizing cultivated land are promising,but scientific guidance is required.B,Zn and Se are essential micronutrients for plants and human body with crucial biological functions,in particular,Se is significant for human health and considered as“the king of anti-cancer”.As these elements required by human or plants are mainly absorbed from soil directly or indirectly,therefore,it is important to understand the contents and distributions of them in the soil of cultivated land for guiding agricultural production.In this work,low-density geochemical survey at the scale of 1∶1000000 was carried out in Tanzania,and the results show that the concentrations of B,Zn and Se in stream sediments are low and their distributions are heterogeneous.According to the distributions of geological units,the existing cultivated land resources can be divided into five regions in Tanzania.Compared with the national background values,the concentrations of B,Zn and Se are insufficient overall but enriched locally in these regions.In general,element concentrations in stream sediments and soil have a positive correlation because of their similar sources,which is essential in agriculture application.Based on the information provided by low-density geochemical data and maps,the Se-sufficient and Se-rich regions were delineated in Tanzania,where can be used to develop Se-rich industries.Finally,this paper believes that geochemical survey is a powerful tool for cultivated land evaluation,agriculture management and land development.

Seismic Potential of the Dodoma Area Within the Manyara Dodoma Rift Segment,Tanzania

On 5th November 2003,the central part of Tanzania (Dodoma),located within the eastern branch of the East African Rift System was struck by an M_s 5.5 earthquake that destroyed a school,a dispensary near its epicenter and caused a huge crack on the Parliamentary building of Tanzania.This was one of the relatively large earthquakes that affected the area after the M_s 6.1 that occurred north of the Dodoma within the Manyara-Dodoma rift segment in May 7,

New U-Pb-Hf zircon isotope data for the Paleoproterozoic Ubendian belt in the Chimala area,SW Tanzania

We present new U-Pb and Hf zircon isotope data on a suite of granitoids from a hitherto unstudied area of the Palaeoproterozoic Lupa terrane of the Ubendian belt in SW Tanzania.The major part of the area comprises a sequence of upper amphibolite grade paragneisses and migmatites.Subsequently,the field relations show a complex history of granitoid emplacement from early pre-tectonic strongly foliated diorite-tonalite-granodiorite orthogneiss to late tectonic,weakly deformed ellipsoidal granitoid plutons.These were followed by emplacement of undeformed K-feldspar rich porphyritic alkali granite.U-Pb zircon data on the granitoids show their emplacement ages span the period^1925 Ma to 1890 Ma and constrain the culmination of the Ubendian orogeny in the Lupa terrane to about 1900 Ma.The undeformed K-feldspar rich Chimala granite,previously considered to be unconformably overlain by the Buanji Group volcano-sedimentary rocks(recently shown to be^1675 Ma,not Neoproterozoic as originally thought)was dated at^1407 Ma showing that it must intrude the sedimentary rocks,although the age relationships are not exposed in the mapping area.This is the first record of early Irumide/Kibaran-aged post-tectonic granites in this part of East Africa.Hf isotope data from the zircons show that the granitoids have a long crustal pre-history stretching back to as far as^3.9 Ga,and showing that the Lupa terrane may form part of the"metacratonic"margin of an originally much more extensive Tanzania Craton.

Resources—Towards Sustainable Use

A resource is any physical or virtual entity of limited availability used to earn good life.Resources are divided into natural and human resources.Natural resources are derived from the environment and are classified on the basis of origin,including biotic resources like forests,animals and their products, marine organisms and minerals.Abiotic resources

Geomedical Hazards Caused by Toxic Contaminants in Mining Areas

The fast-developing field of medical geology (geomedicine) which deals in part with the threat to health from natural silent poisons could help explaining the toxicology of elements released or used in the mining areas.Since the focus in natural hazards work is almost exclusively on the effects on human, the introduction of geomedicine,with its extended concerns for animals and plants,might help balance anthropocentric attitudes toward the environment and, thus,to stress continuities within the biosphere. Different health problems such as ataxia。