The geology and geochemistry of the East African Orogen in Northeastern Mozambique

The geology of northeastern Mozambique has been remapped at 1:250 000 scale. Proterozoic rocks, which make up the bulk of the area, form a number of gneiss complexes defined on the basis of their lithologies, metamorphic grade, structures, tectonic relationships and ages. The gneiss complexes, which contain both ortho- and paragneisses, range from Palaeo- to Neoproterozoic in age, and were juxtaposed along tectonic contacts during the late Neoproterozoic to Cambrian Pan-African Orogeny. In this paper we describe the geological evolution of the terranes north of the Lurio Belt, a major tectonic boundary which separates the complexes described in this paper from the Nampula Complex to the south. The Marrupa, Nairoto and Meluco Complexes are dominated by orthogneisses of felsic to intermediate compositions. Granulitic rocks, including charnockites, are present in the Unango, M’Sawize, Xixano and Ocua Complexes (the last forms the centre of the Lurio Belt). The Neoproterozoic Geci and Txitonga Groups are dominated by metasupracrustal rocks at low metamorphic grades and have been tectonically juxtaposed with the Unango Complex. Geochemical data integrate and support a model of terrain assembly in northeast Mozambique, which is largely published and mainly derived from our new geochronological, lithostratigraphic and structural work. This model shows the contrast between the mainly felsic lower tectonostratigraphic levels (Unango, Marrupa, Nairoto and Meluco Complexes) and the significantly more juvenile overlying complexes (Xixano, Muaquia, M’Sawize, Lalamo and Montepuez Complexes), which were all assembled during the Cambrian Pan-African orogeny. The juxtaposed terranes were stitched by several suites of Cambrian late- to post-tectonic granitoids

Understanding object motion: Recognition, learning, and spatiotemporal reasoning

TIB: RN 3437(145) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Cobalt resources in Europe and the potential for new discoveries

Global demand for cobalt is increasing rapidly as we transition to a low-carbon economy. In order to ensure secure and sustainable supplies of this critical metal there is considerable interest in Europe in understanding the availability of cobalt from indigenous resources. This study reviews information on cobalt resources in Europe and evaluates the potential for additional discoveries. Based on published information and a survey of national mineral resource agencies, 509 cobalt-bearing deposits and occurrences have been identified in 25 countries in Europe. Harmonised cobalt resources, classified using the United Nations Framework Classification (UNFC), have been estimated for 151 deposits in 12 countries where data are available. The calculated total resource comprises 1 342 649 tonnes of contained cobalt metal. This includes: 114 638 tonnes in commercial projects with current cobalt extraction; 370 409 tonnes in potentially commercial projects; 111 107 tonnes in historic estimates compliant with modern reporting; and 746 495 tonnes in non-compliant historic estimates. Analysis of these data reveals that cobalt resources are widely distributed across Europe in deposits of several different types. Global mine production of cobalt is dominated by stratiform sediment-hosted copper deposits, magmatic nickel-copper deposits and nickel laterite deposits, but other deposit types may also be significantly enriched in cobalt. In Europe, current cobalt production is derived from three mines in Finland: the magmatic sulfide deposit at Kevitsa; the Kylylahti deposit of volcanogenic massive sulfide (VMS) affinity; and the black shale-hosted deposit at Sotkamo (Talvivaara). This study has identified 104 deposits in Europe that are currently being explored for cobalt, of which 79 are located in Finland, Norway and Sweden. The Fennoscandian Shield and the Caledonian Belt in these countries are high priority exploration terrains for a variety of cobalt-bearing deposits, notably magmatic Ni-Cu-Co deposits. The Svecofennian, Sveconorwegian and the Caledonian orogenies in Fennoscandia also resulted in the formation of several other cobalt-enriched deposit types. These include chiefly metasediment- and metavolcanic-hosted Co-Cu-Au, VMS, skarn and polymetallic vein deposits. The Kupferschiefer deposits in Poland and Germany are stratiform sediment-hosted Cu deposits with some similarities to the Central African Copperbelt, which is the predominant global producer. However, the cobalt grade in the Kupferschiefer deposits is relatively low (0.005–0.008% Co) and not currently economic to exploit without significant improvement in extraction technology. In the Balkans and Turkey cobalt grades and tonnages are known in 27 nickel laterite deposits, with several containing more than 10 000 tonnes of cobalt metal. Only nickel is currently recovered from these deposits, but new processing technologies such as high-pressure acid leaching could enable cobalt recovery in the future. Small polymetallic cobalt-bearing vein deposits in several European countries have been historic producers of cobalt. Today most are uneconomic, but new technologies and the drive towards locally-sourced raw materials could make them viable future sources of cobalt. Our analysis suggests that geological availability in Europe is not a problem. However, many economic, technological, environmental and social challenges will have to be overcome for exploration projects to become commercial