Nb and REE minerals from the Virulundo carbonatite (Namibe, Angola)

The Virulundo carbonatite is located in SW Angola, in the Namibe province, and is one of the biggest carbonatite outcrops in the world. It is a Cretaceous subvolcanic plug, which belongs to the Parana-Namibia-Angola alkaline-carbonatitic province. It is found intruding Early Archean granitoids, which are fenitized on the contact

Ti-rich Cr-spinel and Ni-Fe-Cu sulphides from the Hamutenha basic-ultrabasic intrusion (Cunene anorthosite complex, Angola)

The Cunene complex is a large group of gabbro-anorthosite intrusions that covers an area of 15.000 km2 between southern part of Angola and northern Namibia. Although ultrabasic rocks have not been found to data in the main anorthositic intrusion of the Cunene complex, a great number of small basic-ultrabasic bodies appear close to the west margin of the main intrusion

Ti-V oxide deposits in the Kunene Anorthositic Complex (SW Angola)

The Kunene Complex, outcropping between SW Angola and NW Namibia, is one of the biggest Proterozoic anorthositic complexes in the world [1]. It is cut by a set of Ti-Fe oxide dykes or lenticular bodies, that are hectometric to kilometric in length and metric to decametric in width

Composición de la Cr-espinela del cuerpo máfico-ultramáfico de Hamutenha, Angola: Implicaciones petrogenéticas y metalogenéticas

En las inmediaciones del poblado de Hamutenha, cerca de Chibia (Angola), aflora un conjunto de cuerpos intrusivos formados por materiales básicos y ultrabásicos, encajados en rocas graníticas. En la zona existen indicios de mineralizaciones diseminadas de Ni y Cr. El objetivo de este trabajo es evaluar dichas mineralizaciones y establecer los parámetros petrogenéticos y metalogenéticos del cuerpo intrusivo, a partir de la descripción y la composición química de las Cr-espinelas presentes en los miembros más básicos

Depósitos ortomagmáticos de Fe-Ti en anortositas del complejo de Cunene (Angola)

Los mayores depósitos de titanio del mundo se encuentran asociados a cuerpos anortosíticos. Algunos de los más importantes están poco estudiados y se conoce poco sobre sus condiciones de formación. En este trabajo se aportan los primeros datos de composición mineral de algunos depósitos de Fe-Ti hasta ahora muy poco conocidos pero de gran importancia, situados en el complejo anortosítico de Cunene (Angola)

Fe-Ti(-V) oxide deposits of the Kunene anorthosite complex (SW Angola): Mineralogy and thermo-oxybarometry

The Kunene Intrusive Complex (KIC), in NW Namibia and SW Angola, is one of the largest Proterozoic anorthosite massif-type exposures in the world. A geochemical, mineralogical and petrological study of four Fe-Ti(-V) oxide bodies located in the understudied Angolan part of the KIC has been performed. The massive Fe-Ti(-V) oxide bodies, locally apatite-rich (nelsonites), are lenticular or dike-like. They consist mostly of titaniferous magnetite, ilmenite and minor aluminous spinel, apatite, olivine and graphite. Titaniferous magnetite displays a wide variety of subsolvus features, including aluminous spinel-magnetite-ulvöspinel exsolutions and ilmenite (Trellis) exsolutions. This work estimated the composition of the titaniferous magnetite prior to the exsolution, in order to calculate the temperature and oxygen fugacity of the different lithologies of each ore body. The thermo-oxybarometry results obtained range from 600 °C to 820 °C and fO2 from 10−24.7 to 10−14.7. These values do not correspond to magmatic crystallization in equilibrium, but to a later re-equilibration. In addition, the mineralogical and geochemical results indicate that the studied ore bodies contain economic reserves of Ti, V, and possibly of P and REE