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Lexicon of lithostratigraphic units for the Sudan
Published in J.R. Vail, Lexicon of Geological Terms for the Sudan, 2022
Curtis and Lenz (1985) and Curtis and Brinkmann (1985) have described igneous complexes from the Nuba Mountains. The Buram Complex is 13 x 6.5 km, and consists of a circular intrusion, the Jebel Buram Quartz- Alkali Syenite, with a core of subalkaline syenite; patches of felsic pyroclastic and trachytic lavas are preserved, particularly as roof pendants in porphyritic alkali microgranite. The country rocks are Basement Complex metasedimentary and metavolcanic rocks and dioritic gneisses.
Statistical analysis of discontinuities, with a special reference to Rock Quality Designation
Published in Wang Yuehan, Ge Shirong, Guo Guangli, Mining Science and Technology, 2004
The study area is located in the tectonic zone of Sanandaj Sirjan. The ore body is covered by the recent alluvium. The mineralized zone has a vertical mineralization zonation from top to bottom which are top magnetite, oxide zone and bottom magnetite. The country rocks are mainly composed of metamorphic rocks such as schist, phyllites, amphibolites, gneiss and marble. These rock units are strongly folded and might have been metamorphosed in Late Paleozoic and Early Mesozoic. The metamorphic rocks are highly tectonized. Towards the north, this area contains Permian formations that are mainly composed of limestone, dolomite along with minor outcrops of shale and crystallized sandstone. The Mesozoic-Tertiary formations belonging to the Zagros folded belt are outcropping in the southern part of the area. The faulted and sheared rocks of coloured mélange, which are composed of radiolarite, ophiolite, shale and limestone, are in the northern part of the area. The tectonic features have a northwest southeast trend. Recent alluvium is covering most parts of the study area (Sabzei, 1998).
Structural control of mineralization in Cerro Áspero, Argentina
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
D. I. Mutti, S. González Chiozza, C. Méndez
Three main styles of mineralization with zonal distribution are present in the district: 1) wolframite with minor sulfides in quartz veins and breccia bodies hosted mainly in schists and amphibolites within ∼2 km from the contact with the Cerro Áspero granite; 2) sulfides with minor wolframite in quartz veins hosted in amphibolites, schists and gneisses, within ∼10 km from the contact with the granitic rocks; and 3) íluorite with quartz and chalcedony veins emplaced in the contact zone between the granitic batholith and the schists. The location and disposition of the ore bodies is closely related to the structural features of the country rocks. In this paper we present a systematic structural analysis of the penetrative structures, vein disposition and main lineaments, intended to identify controls on the mineralization process with focus on the first two styles of mineralization.
Geochemical and health risk evaluation of fluoride rich groundwater in Sattenapalle Region, Guntur district, Andhra Pradesh, India
Published in Human and Ecological Risk Assessment: An International Journal, 2020
N. Subba Rao, B. Ravindra, Jianhua Wu
Spatial variation and distribution of fluoride content in the groundwater shows uneven pattern (Figure 8). It could be due to differences in (a) water-rock interactions, (b) the availability of source minerals present in the country rocks and (c) weathering and dissolution of minerals, ion exchange and evaporation processes (Raju et al. 2009, 2012; Rao et al. 2014; Subba Rao 2011, 2017a; Subba Rao et al. 2017b). Similar observations have also been reported from Telangana region (Reddy et al. 2010a, 2010b; Subba Rao et al. 2016, 2019b; Narsimha and Rajitha 2018) and Andhra Pradesh region (Subba Rao 2017a; Subba Rao et al. 2013), which are the adjacent States in India with more or less the similar hydrogeological environmental conditions.
Genesis and possible applications of Lwamondo and Zebediela Kaolins, Limpopo Province, South Africa
Published in Applied Earth Science, 2022
Avhatakali Raphalalani, Georges-Ivo Ekosse, John Odiyo, Jason Ogola, Olaonipekun Oyebanjo, Nenita Bukalo
The Zebediela Kaolin is exposed in three quarries. The country rocks comprised mudrocks, shale, breccia, and chert. The first quarry comprised a yellowish kaolin at the base, overlain by reddish-brown, pale brown, and light brown kaolin layers (Figure 3(a)). The second quarry has greyish and reddish kaolins. An iron-rich vein cuts across the kaolins in one of the quarries, and above which is found a brown to reddish kaolin layer (Figure 3(b)). The third quarry had whitish kaolin (Figure 3(c)), whose formation was characterised by a major NNW-SE trending fault, truncated by numerous smaller veins.
A review of the geological settings, ages and economic potentials of carbonatites in the Democratic Republic of Congo
Published in Applied Earth Science, 2021
Georges M. Kasay, Anthony T. Bolarinwa, Olawale K. Aromolaran, Charles Nzolang, Vikandy S. Mambo
The country rocks are orthogneisses, quartzites, dolerites and gabbro (Woolley et al. 1995; Kasay 2018). The gabbro is composed of clino- and orthopyroxenes, and amphiboles. There is no clear relationship between these rocks and the carbonatite intrusion, according to Woolley et al. (1995). - Calcite carbonatite