Academic literature on the topic 'Namibia {Geologie}'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Namibia {Geologie}.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Namibia {Geologie}"
1
Eckardt, Frank D., Ian Livingstone, Mary Seely, and Johanna Von holdt. "The surface geology and geomorphology around gobabeb, namib desert, namibia." Geografiska Annaler: Series A, Physical Geography 95, no. 4 (December 2013): 271–84. http://dx.doi.org/10.1111/geoa.12028.
Full text
2
Fleming, Alastair, and Zoé Fleming. "Topics Namibia for the amateur geologist." Geology Today 16, no. 3 (May 2000): 107–11. http://dx.doi.org/10.1046/j.1365-2451.2000.00006.x.
Full text
3
Basson, I. J., M. J. McCall, J. Andrew, and E. Daweti. "Structural controls on mineralisation at the Namib Lead and Zinc Mine, Damara Belt, Namibia." Ore Geology Reviews 95 (April 2018): 931–44. http://dx.doi.org/10.1016/j.oregeorev.2018.03.028.
Full text
4
Clemson, J., J. Cartwright, and R. Swart. "The Namib Rift: a rift system of possible Karoo age, offshore Namibia." Geological Society, London, Special Publications 153, no. 1 (1999): 381–402. http://dx.doi.org/10.1144/gsl.sp.1999.153.01.23.
Full text
5
Eckardt, F. D., and B. Spiro. "The origin of sulphur in gypsum and dissolved sulphate in the Central Namib Desert, Namibia." Sedimentary Geology 123, no. 3-4 (February 1999): 255–73. http://dx.doi.org/10.1016/s0037-0738(98)00137-7.
Full text
6
Cook, Robert B. "Connoisseur'sChoice: Cerussite, Tsumeb, Namibia." Rocks & Minerals 72, no. 3 (May 1997): 176–80. http://dx.doi.org/10.1080/00357529709605035.
Full text
7
Miller, R. McG, C. Krapf, T. Hoey, J. Fitchett, A.-K. Nguno, R. Muyambas, A. Ndeutepo, A. Medialdea, A. Whitehead, and I. Stengel. "A sedimentological record of fluvial-aeolian interactions and climate variability in the hyperarid northern Namib Desert, Namibia." South African Journal of Geology 124, no. 3 (September 1, 2021): 575–610. http://dx.doi.org/10.25131/sajg.124.0008.
Full textAbstract:
Abstract The aeolian regime of the 100 km wide, hyperarid Namib Desert has been sporadically punctuated by the deposition of fluvial sediments generated during periods of higher humidity either further inland or well within the desert from Late Oligocene to Late Holocene. Four new Late Cenozoic formations are described from the northern Skeleton Coast and compared with formations further south: the Klein Nadas, Nadas (gravels, sands), Vulture’s Nest (silts) and Uniab Boulder Formations. The Klein Nadas Formation is a trimodal mass-flow fan consisting of thousands of huge, remobilised, end-Carboniferous Dwyka glacial boulders, many >3 m in length, set in an abundant, K-feldspar-rich and sandy matrix of fine gravel. Deluge rains over the smallest catchments deep within the northern Namib were the driving agent for the Klein Nadas Fan, the termination of which, with its contained boulders, rests on the coastal salt pans. These rains also resulted in catastrophic mass flows in several of the other northern Namib rivers. The Uniab Boulder Formation, being one, consists only of huge free-standing boulders. Gravelly fluvial deposition took place during global interglacial and glacial events. The Skeleton Coast Erg and other smaller dune trains blocked the rivers at times. The low-energy, thinly bedded silt deposits of the central and northern Namib are quite distinctive from the sands and gravels of older deposits. Their intermittent deposition is illustrated by bioturbation and pedogenesis of individual layers. Published offshore proxy climatological data (pollens, upwelling, wind, sea surface temperatures) point to expansion of the winter-rainfall regime of the southern Cape into southwestern Angola during strong glacial periods between the Upper Pleistocene and Holocene. In contrast to deposition initiated by short summer thunder storms, we contend that the silt successions are river-end accumulations within which each layer was deposited by runoff from comparatively gentle winter rains that lasted several days.
8
Borg, G., K. Karner, M. Buxton, R. Armstrong, and S. W. v. d. Merwe. "Geology of the Skorpion Supergene Zinc Deposit, Southern Namibia." Economic Geology 98, no. 4 (June 1, 2003): 749–71. http://dx.doi.org/10.2113/gsecongeo.98.4.749.
Full text
9
Cook, Robert B. "Connoisseur's Choice: Mimetite, Tsumeb, Namibia." Rocks & Minerals 76, no. 2 (March 2001): 114–17. http://dx.doi.org/10.1080/00357520109603204.
Full text
10
Cook, Robert B. "Connoisseur's Choice: Smithsonite, Tsumeb, Namibia." Rocks & Minerals 75, no. 3 (May 2000): 176–79. http://dx.doi.org/10.1080/00357520009605637.
Full textDissertations / Theses on the topic "Namibia {Geologie}"
1
Raab, Matthias Johannes. "The geomorphic response of the passive continental margin of northern Namibia to Gondwana break-up and global scale tectonics." Doctoral thesis, [S.l.] : [s.n.], 2001. http://webdoc.sub.gwdg.de/diss/2001/raab/index.html.
Full text
2
Hartmann, Kerstin. "Jungquartäre Reliefentwicklung, Substratgenese, Klimageschichte und aktuelle Morphodynamik am Ostrand der Namib in der Region Hartmannstal-Marienflusstal (NW-Namibia) /." Köln : Geograph. Inst. der Univ. zu Köln, 2007. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=016293693&line_number=0002&func_code=DB_RECORDS&service_type=MEDIA.
Full text
3
Van, der Merwe Hendrik Naude. "Remote sensing driven lithological discrimination within nappes of the Naukluft Nappe Complex, Namibia." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97147.
Full textAbstract:
Thesis (MSc)--Stellenbosch University, 2015.ENGLISH ABSTRACT: Geological remote sensing is a powerful tool for lithological discrimination, especially in arid regions with minimal vegetative cover to obscure rock exposures. Commercial multispectral imaging satellites provide a broad spectral range with which to target specific rock types. Landsat ETM+ (7), ASTER, and SPOT 5 multispectral images were acquired and digitally processed: band ratioing, principle components analysis, and maximum likelihood supervised classification. The sensors were evaluated on the ability to discriminate between sedimentary rocks in a structurally complex setting. The study focusses on the formations of the Naukluft Nappe Complex, Namibia. Previous work of the area had to be consulted in order to identify the main target rock types. Dolomite, limestone, quartzite, and shale were determined to make up the majority of rock types in the area. Landsat, ASTER, and SPOT 5 imagery were acquired and pre-processed. Each was subjected to transform techniques: band ratios and PCA. Band ratios were tailored to highlighted target rock types as well as a number of control ratios to ensure the integrity of important ratios. PCA components were inspected to find the most useful ones which were combined into FCCs. Transform results, expert knowledge, and a geological map were consulted to identify training and accuracy samples for the supervised classifications. All three classifications made use of the same set of training and accuracy samples to facilitate useful comparisons. Transform results were promising for Landsat and ASTER images, while SPOT 5 struggled. The limited spectral resolution of SPOT 5 limited its use for identifying target rock types, with the superior spatial resolution contributing very little. Landsat benefitted from good spectral resolution. This allowed for good performance with highlighting limestone and dolomite, while being less successful with shale. Quartzite was a real problem as the spectral resolution of Landsat could not cover this range as well. ASTER, having the highest spectral resolution, could distinguish between all four target rock types. Landsat and ASTER results suffered in areas where formations were relatively thin (smaller than sensor spatial resolution). The supervised classification results were similar to the transforms in that both Landsat and ASTER provided useful results, while SPOT 5 failed to yield definitive results. Accuracy assessment determined that ASTER performed the best at 98.72%. Landsat produced an accuracy of 93.29% while SPOT 5 was 80.17% accuracy. Landsat completely overestimated the amount of quartzite present, while all results classified significant proportions Quaternary sediments as shale. Limestone was well represented in even the poorest results, while dolomite usually struggled in areas where it was in close association with quartzite. Silica yields relatively strong responses in the TIR spectrum which could lead to misclassification of dolomite, which also has strong TIR signatures.
AFRIKAANSE OPSOMMING: Geologiese afstandswaarneming is 'n kragtige tegniek vir litologiese diskriminasie, veral in droë streke met minimale plantbedekking om dagsome te verduister. Kommersiële multispektrale satelliete beelde bied 'n breë spektrale reeks waarmee spesifieke gesteentetipes geteiken kan word. Landsat ETM + (7), ASTER, en SPOT 5 multispektrale beelde was bekom en digitaal verwerk: bandverhoudings, hoofkomponente-ontleding, en maksimum waarskynlikheid klassifikasie. Die sensors is geëvalueer op hul vermoë om te onderskei tussen sedimentêre gesteentes in 'n struktureel komplekse omgewing. Die studie fokus op die formasies van die Naukluft Dekblad Kompleks, Namibië. Vorige werk van die area was geraadpleeg om die hoofgesteentetipes te identifiseer. Dit was bepaal dat dolomiet, kalksteen, kwartsiet, en skalie die oorgrote meerderheid van kliptipes in area opgemaak het. Landsat, ASTER, en SPOT 5 beelde is verkry en voorverwerk. Elke beeld was onderwerp aan transformasietegnieke: bandverhoudings en hoofkomponente-ontleding. Bandverhoudings is aangepas om teiken rotstipes uit te lig asook 'n aantal kontrole bandverhoudings om die integriteit van belangrike verhoudings te verseker. Hoofkomponente-ontleding komponente is ondersoek om die mees bruikbares te vind en dié was gekombineer in valse kleur samestellings. Transformasie resultate, deskundige kennis, en 'n geologiese kaart was geraadpleeg om opleidings- en verwysingsmonsters was verkry vanaf die beelde vir die klassifikasies. Al drie klassifikasies gebruik gemaak van dieselfde stel van die opleiding- en akkuraatheidsmonsters om sodoende betekenisvolle vergelykings te verseker. Transformasie resultate is belowend vir Landsat en ASTER beelde, terwyl SPOT 5 minder bruikbaar was. Die noue spektrale resolusie van SPOT 5 beperk die gebruik daarvan vir die identifisering van teiken gesteentetipes terwyl die hoë ruimtelike resolusie baie min bydra. Landsat het voordeel getrek uit goeie spektrale resolusie. Dit goeie resultate opgelwer met die klem op kalksteen en dolomiet, terwyl skalie aansienlik swakker resultate opgelewer het. Kwartsiet was 'n werklike probleem omdat die spektrale resolusie van Landsat nie breed genoeg was om hierdie kliptipe te onderskei nie. ASTER, met die hoogste spektrale resolusie, kon onderskei tussen al vier teiken rotstipes. Landsat en ASTER resultate was baie negatief beïnvloed in gebiede waar formasies relatief dun was (kleiner as sensor ruimtelike resolusie). Die klassifikasie resultate was soortgelyk aan die transformasies in dat beide Landsat en ASTER nuttige resultate opgelewer het, terwyl SPOT 5 misluk het. Akkuraatheids assessering het bepaal dat ASTER die beste gevaar het met 98,72%. Landsat het 'n akkuraatheid van 93,29% opgelewer, terwyl SPOT 5 80,17% akkuraat was. Landsat het die hoeveelheid kwartsiet heeltemal oorskat, terwyl al die resultate groot hoeveelhede Kwaternêre sedimente as skalie geklassifiseer het. Kalksteen is goed verteenwoordig in tot die armste resultate, terwyl resultate gewoonlik afgeneem het waar dolomiet in noue verband met kwartsiet was. Dit is moontlik asgevolg van silika se relatiewe sterk reaksies in die termiese infra-rooi spektrum wat kan lei tot die foutiewe klassifisering met dolomiet (wat ook sterk reageer in die TIR spektrum).
4
Moroni, Marilena. "The geology, petrology and geochemistry of the mineralization and hydrothermal alteration at Ongeama, Ongombo and Matchless West Extension, Namibia." Thesis, Rhodes University, 1991. http://hdl.handle.net/10962/d1007693.
Full textAbstract:
The Matchless Amphibolite Belt (Damara Orogen, Namibia) hosts several volcanogenic-exhalative, sediment-hosted stratiform cupriferous pyrite deposits. These are thought to be related to submarine volcanism during the early evolutionary stages of a narrow Damaran ocean, the Matchless Trough. The mineralized bodies examined (Ongeama, Ongombo and Matchless West Extension) are deformed and metamorphosed to low-medium grade (greenschist-amphibolite facies). They are associated with metapelite and amphibolite country rocks, and crop out as prominent limonite-rich gossans. The elongated shape of the sulphide bodies suggests a structural control. The mineralization normally consists of a variably developed massive sulphide portion, either quartz-, talc- or amphibole-bearing, and a stratigraphically overlying, extensive horizon of sulphide- and baryte-bearing exhalite (magnetite quartzite and less common talc- and actinolite-bearing schists). Lateral and vertical mineralogical changes within the mineralization match with significant variations in the element distribution. A metamorphosed and deformed alteration pipe, indicating the position of the fluid conduit, can be recognized in association with some ore bodies. The formation of quartz-muscovite and chlorite alteration envelopes (Ongeama, Matchless West Extension) and the presence of subtle mineralogical changes (Ongombo) in the immediate wallrocks, accompanied by extensive redistribution, leaching and introduction of elements from outside, suggest the hydrothermal metasomatic origin of the alteration zones. Element zoning within the mineralized bodies can be related to the original position of the vent, possibly coinciding with the intersection of the axis of the alteration pipe with the sulphide body. Cu, Zn, Au (pro parte) and Mo are enriched proximal to the vent, whereas Pb, Ba, Mn, Ag, Au, Sn, Bi and W enrichment characterizes the distal facies of the mineralization. In spite of the obliterating and disrupting effects of the regional dynamo-metamorphism, the element distribution within the mineralization and alteration zones examined is comparable with the geochemical trends observed in present-day mineralizing systems in early- stage oceanic environments (e.g. Guaymas Basin). During exploration for blind volcanogenic mineralization, the detection of hydrothermally altered rocks is fundamental in indicating the proximity to the mineralization. The localization of the alteration zone is also important in the interpretation of the regional geology of the explored area: in deformed terrains the assessment of the stratigraphic position of the alteration zone, relative to the mineralization, helps in establishing the polarity of the sequence.
5
Cloete, Melissa. "Microbial diversity of the Namib Desert salt pans." University of the Western Cape, 2015. http://hdl.handle.net/11394/5230.
Full textAbstract:
>Magister Scientiae - MScSalt pans are a characteristic feature of many dry deserts. The microbial communities inhabiting salt pans are thought to be particularly complex and are generally dominated by halophilic microorganisms. Although saline pools are frequently found within the hyper-arid Namib Desert, the microbial communities of these saline sites have been scarcely investigated. The aim of the present study was to characterise the archaeal, bacterial and cyanobacterial diversity inhabiting these extreme saline pools using three culture independent molecular techniques (DGGE, T-RFLP and 16S rRNA clone libraries). The physiochemical results, mainly the conductivity readings recorded from the sampling sites, indicated that the Gobabeb (103.0mS/cm) region was less saline than the two Swakopmund [(Sps01) (150.0mS/cm) and Sps02 (180.0mS/cm)] sites. Results obtained from DGGE and T-RFLP data were in agreement for both bacterial and cyanobacterial analysis indicating that the Gobabeb site was more diverse than the two Swakopmund sites (Sps01 and Sps02). In comparison, the archaeal community profiles for DGGE and T-RFLP analysis were in agreement illustrating that the archaeal community were more abundant in the two extreme Swakopmund saline sites. Phylogenetic data obtained from 16S rRNA gene clone libraries identified halophilic phylotypes (Rhodothermaceae, Idiomarinaceae Puniceicoccaceae and Cyanobacteria/Chloroplast, Family VII) normally associated with salt rich sites. In addition, a large number of unclassified taxa were identified. To conclude, the study highlighted the presence of a rich microbial diversity present within the salt pans of the Namib Desert and establishes a platform for future investigations.
National Research Foundation
6
Walraven, Felix Caspar. "The geology and alteration-mineralisation of the Gamigab Tin Prospect, Damaraland, Namibia." Thesis, Rhodes University, 1990. http://hdl.handle.net/10962/d1005568.
Full textAbstract:
The stratigraphy at the Gamigab Sn prospect consists of two mainly schistose units separated by a thick marble unit which have been assigned to the Orusewa, the Karibib and the Kuiseb Formations respectively. Four phases of folding affected the lithologies with the south-south-west trending F2 folds defining the main structures in the region. The area underwent low grades of metamorphism. Temperatures were in the range 420° to 500°C and pressures less than 2 kbars. The effects of contact metamorphism are seen in the south-east and south-west. Regional metamorphism outlasted the deformation and contact metamorphism started late during deformation. Two Karoo-age intrusions penetrated the metasediments north of the mineralisation. One is an altered porphyry plug and the other is a weathered dolerite plug, the latter containing xenoliths of undeformed Karoo sediments. Cassiterite is hosted within east-west trending quartz veins that cross-cut previously altered schistose country rocks. The alteration types include sericitisation, tourmalinisation, carbonatisation and ferruginisation. Preliminary Rb/Sr dating on muscovite from the alteration zone suggests an age of 509 ± 11 Ma. Breccias of probable hydrothermal origin are spatially associated with the mineralisation. These hydraulic breccias occur in antiformal structures within the marble and developed in response to a sudden pressure release due to a build up of fluids at the contact between the schistose Orusewa and carbonate Karibib Formations.
7
Guj, P., and P. Guj. "The Damara mobile belt in the south-Western Kaokoveld." Doctoral thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/23739.
Full textAbstract:
After the establishment of the N-S Andib-Ganamub trough, the ubiquitous Lower Nosib subarkose was succeeded in the west by the Upper Nosib greywacke which indicates that orthogeosynclinal subsidence was already active in pre-Damara times. A pulse of NNE folding (F₁N) concluded this sedinentary cycle and was accompanied by amphibolite-grade metamorphism (M₁), occasional migmatisation (A₁), and later feldspar blastesis. This episode was most intense in the west, so that the overlying Damara rocks paraconformable in the east, are unconformable there. Martin's (1965) separation of the succeeding Damara basin into a western eugeosyncline and an eastern miogeosyncline applies very well to this area, though the separating hinge-line appears to have been located farther to the west (±80 Km) of the Kamanjab inlier, along the western flank of a N-S geanticlinal belt. The Lower Bakos semipelite and lenticular carbonate, thinning out against the eastern flank of this positive element controlling the deposition, may, prior to deformation, have created a transition between the western eugeosynclinal greywacke and the eastern miogeosynclinal Lower Otari carbonates. The fractured hinge-zone provided channels for the ascent of syndepositional intrusions and volcanics. Regional erosion following upwarping in the east caused a large influx of detritus into the Khomas furrow prior to the disconformable deposition of the Tillite Substage, which is the only reliable chronostratigraphic link between the base of the Upper Otavi and that of the Upper Bakos Series, the latter partially intertongueing with the succeeding Khomas Series. Gravitational creeping of the miogeosynclinal carbonates down the western slope of the upwarped Kamanjab inlier towards the sinking basin, produced the first folding (F₂O) in the east. Almost contemporaneously, buoyant uplifting forces, related to anatexis (A₂) along the axis of the eugeosyncline, created slopes sufficient to convey nappes (F₂S) of scarcely metamorphosed Damara schists towards the eastern foreland, overriding the miogeosyncline along the N-S Sesfontein Thrust. Eastern foredeeps were rapidly filled by the Mulden molasse. Steep slip folding (F₂S and F₄) in the cores and roots, and the formation of scattered domes at depth, controlled the successive structural evolution of the nappes. Large-scale axial undulations were later produced by orthogonally superposed F₃ folds striking east. The Damaran metamorphism (M₂ ), which outlasted deformation, has a Barrovian character and grades in the Damara sediments from amphibolite (sillimanite) grade in the west to greenschist (sericite- chlorite) grade in the east. In the previously dehydrated, deformed and metamorphosed, polymetamorphic (M₁/M₂ ) Nosib terrains, retrograde parageneses and transition granulites developed to the east and to the west of the Damaran hornblende-oligoclase isograd respectively. The Damaran tectono-thermal episode culminated in advanced migmatisation of the Khomas greywacke (possibly equivalent to the Salem granite-gneiss) and final anatexis (A₂ ) in the late-kinematic Ganias -Uhima (possibly equivalent to the Donkerhoek) granite, followed by widespread feldspar blastesis. The drop in rheomorphism in the deformed mass at the margin of the migmatite zone induced intense shearing and produced belts of mylonite and cataclastic gneiss. At a later stage, the Sesfontein Thrust was buffered against the Otavi dolomite relief and its speed of advancement reduced to match that of the erosion of its frontal toe, which now separates two completely different structural-stratigraphic domains: i) an eastern miogeosynclinal, feebly metamorphosed and volcanic-free domain (Damara System, Outjo Facies) deformed into non-basement-involving tectonites, overridden by ii) a western domain of suprastructural nappes and metamorphosed eugeosynclinal sediments (Damara System, Swakop Facies) deformed in response to basementinvolving tectonic processes promoted by deeply seated anatexis along the axis of the former eugeosyncline. The present model involves many stratigraphic revisions, one of the most important being that no rocks older than the Nosib Formation outcrop in the area and possibly along most of the Damara mobile belt in the western Kaokoveld.
8
Viljoen, Wayne. "Geology, structure and mineralization of the Onguati area, Karibib district, central Namibia." Thesis, Rhodes University, 2005. http://hdl.handle.net/10962/d1005576.
Full textAbstract:
The study area is situated in the Southern Central Zone of the intracontinental Pan-African Damara Orogen, approximately 20km NNE of Navachab Gold Mine in the Karibib district of Namibia. Mesothermal vein systems with Cu-Fe±Au mineralization are hosted by amphibolite facies calcitic and dolomitic marbles belonging to the Navachab Member of the Karibib Formation, and are best developed around the defunct Onguati Copper Mine, Brown Mountain and Western Workings areas. The Onguati study area is located in the saddle region of a moderately-to-gently inclined anticlinorium that experienced significant flattening during NNW-SSE-directed compression. The parallelogram arrangement of ENE- and NNE-trending thrusts and reverse faults that surround the Onguati study area may have developed when the direction of greatest principle subregional stress was oriented WSW-ESE. These structures define part of a Riedel shear system and later faults may have developed in the position of R and P shears respectively. Significant strain partitioning occurred between the ductile calcitic marbles which host the best developed, shear-related vein systems and the more competent dolomitic marbles. The thickness distributions of veins in the marbles of the Onguati Mine, Brown Mountain and Western Workings areas conform to a fractal or power-law distribution, The most intensely mineralized vein systems in the Onguati Mine and Western Workings calcitic marbles share similar low fractal dimensions (D-values) of 0.41 and 0.37 respectively. Veins In the calcitic and dolomitic marbles of the Brown Mountain area and in the dolomitic marbles of Western Workings have elevated D-values (>0.60) and are poorly mineralized. The low D-values «0.40) of the well mineralized vein systems reflect the higher degree of fracture connectivity. These vein systems were capable of efficiently draining and localizing large volumes of mineralizing fluids from crustal-scale structures. A metamorphic devolatization model is proposed where the entire Damaran metasedimentary and meta-volcanic package is seen as a large source area of very low concentrations of Cu, Au and other metals. Localization of deformation into crustal-scale faults and shear zones led to regional-scale hydrothermal fluid flow and focussing into the upstream fracture networks of the Onguati study area. Strong mineralization resulted when fluids encountered the reactive marble lithologies
9
Johnson, Shannon D. "Structural geology of the Usakos Dome in the Damara Belt, Namibia." Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/50457.
Full textAbstract:
Thesis (MSc)--Stellenbosch University, 2005.ENGLISH ABSTRACT: The northeast-trending south Central Zone (sCZ) of the Pan-African Damara belt in central Namibia is structurally characterized by kilometer-scale, northeast-trending dome structures developed in Neoproterozoic rocks of the Damara Sequence. A number of different structural models have been proposed for the formation of these domes in the literature. This study describes the structural geology of the Usakos dome. The study discusses the structural evolution of the dome within the regional framework of the cSZ that represents the high-grade metamorphic axis of the Damara Belt, characterized by voluminous Pan-African granitoids. The northeastern part of the Usakos dome is developed as an upright- to northwestverging anticlinorium containing a steep southeasterly-dipping axial planar foliation. The northeast fold trend persists into the southwestern parts of the Usakos dome. However, this southwestern core of the dome is inundated by synkinematic granitic sheets. Distinct marker horizons of the Damara Sequence outcrop as screens within the granite, preserving a ghost stratigraphy. These screens illustrate the position and orientation of second-order folds. Significantly, most of the stratigraphy of the Damara Sequence is overturned in these folds. For example, some second-order anticlines developed in the northeastern parts of the Usakos dome can be followed along their axial traces into the southwestern hinge of the dome, where they appear as synformal anticlines, i.e. synformal structures cored by older strata, plunging towards the northeast. The inverted stratigraphy and northeasterly fold plunges suggest the northeast-trending folds are refolded by second-generation, northwest-trending folds, thus, forming kilometer-scale Type-2 interference folds. The resulting fold geometries are strongly non-cylindrical, approaching southwest-closing sheath folds indicating a top-to-the-southwest material transport. Lower-order folds in this overturned domain show radial fold plunges, plunging away from the centre of the dome core, as well as a shallowly-dipping schistosity. The close spatial and temporal relationship between granite intrusion and the formation of the southwest-vergent, sheath-type folds, radial distribution of fold plunges and the subhorizontal foliation confined to the southwestern hinge of the Usakos dome are interpreted to signify the rheological weakening and ensuing collapse of the developing first-order Usakos dome immediately above the synkinematic granite intrusions. Orogenparallel, southwest-vergent sheath folds and top-to-the southwest extrusion of the southwestern parts of the Usakos dome and northwest-vergent folding and thrusting characterizing the northeastern extent of the Usakos dome are both responses to the northwest-southeast- directed contractional tectonics recorded during the main collisional phase in the Damara belt. On a regional scale, the Usakos dome represents the link between the foreland-vergent northeastern part of the sCZ and the southwest-vergent, high-grade southwestern parts of the sCZ. The results of this study illustrate how dramatic variations in structural styles may be caused by the localized and transient rheological weakening of the crust during plutonic activity.
AFRIKAANSE OPSOMMING: Die noordoos-strekkende, suidelike Sentrale Sone (sSS) van die Pan-Afrikaanse Damara gordel in sentraal Namibië word karakteriseer deur kilometer-skaal, noordoosstrekkende koepel strukture, ontwikkel in die Neoproterozoïkum gesteentes van die Damara Opeenvolging. 'n Aantal verskillende struktuur modelle is voorgestel in die literatuur vir die vorming van hierdie koepels. Hierdie ondersoek beskryf die struktuur geologie van die Usakos koepel. Die ondersoek bespreek die strukturele ontwikkeling van die koepel in die regionale konteks van die sSS, wat die hoë graadse metamorfe magmatiese as van die Damara Gordel verteenwoordig, en karakteriseer word deur omvangryke Pan-Afrikaanse granitoïede. Die noordoostelike gedeelte van die Usakos koepel is ontwikkel as 'n antiklinorium met 'n vertikale- tot noordwestelike kantelrigting. wat 'n steil hellende, suidoostelike asvlak planêre foliasie bevat. Die noordoos-strekkende plooiing kom voor tot in die suidwestelike kern van die Usakos wat ingedring is deur sinkinematiese granitiese plate. Die posisie en oriëntasie van tweede-orde plooie is afgebeeld in die graniete deur 'n skimstratigrafie wat preserveer is deur duidelike merker horisonne van die Damara Opeenvolging. Die stratigrafie van die Damara Opeenvolging is opmerklik meestal omgekeer in hierdie plooie. Byvoorbeeld, tweede-orde antikliene ontwikkel in die noordoostelike gedeelte van die Usakos koepel kan gevolg word langs hul asvlakspore tot in die suidwestelike skarnier van die koepel, waar dit voorkom as sinforme antikliene, d.w.s. sinforme strukture met ouer strata in die kern wat na die noordooste duik. Die omgekeerde stratigrafie en noordoostelike plooi duiking impliseer dat die noordoosstrekkende plooie weer geplooi is deur tweede-generasie, noordwes-strekkende plooie, wat dus aanleiding gegee het tot die vorming van kilometer-skaal, tipe-2 interferensie plooie. Die gevolglike plooi geometrieë is uitdruklik nie-silindries, en toon 'n oorgang na skede plooie met 'n sluiting na die suidweste, wat dui op 'n bokant-na-die-suidweste materiaal vervoer. Laer-orde plooie in die omgekeerde domein vertoon radiale duiking van die plooie, weg van die middelpunt van die koepel kern, sowel as 'n vlak hellende skistositeit. Die noue ruimtelike en temporele verwantskap tussen graniet intrusie en die vorming van skede-tipe plooie met 'n kantelrigting na die suidweste, die radiale verspreiding van plooi duiking, en die subhorisontale foliasie wat beperk is tot die suidwestelike skarnier van die Usakos koepel, word interpreteer as 'n aanduiding van die reologiese verswakking en die gevolglike ineenstorting van die ontwikkelende eerste-orde Usakos koepel, onmiddellik aan die bokant van die sinkinematiese graniet intrusies. Die orogeenparalleie skede plooie met kantelrigting na die suidweste en bokant-na-die-suidweste ekstrusie van die suidwestelike gedeelte van die Usakos koepel, en plooiing met kantelrigting na die noordweste en stootverskuiwing wat kenmerkend is van die noordoostelike gedeelte van die Usakos koepel, is beide 'n reaksie op die noordwessuidoos- gerigte vernouings tektoniek opgeteken gedurende die hoof botsings fase in die Damara gordel. Op 'n regionale skaal verteenwoordig die Usakos koepel die verbinding tussen die noordoostelike gedeelte van die sSS met 'n voorland kantelrigting. en die hoë graad suidwestelike gedeelte van die sSS met 'n kantelrigting na die suidweste. Die resultate van hierdie ondersoek toon aan hoe dramatiese variasies in struktuur style veroorsaak kan word deur die gelokaliseerde en kortstondige reologiese verswakking van die kors gedurende plutoniese aktiwiteit.
10
Nagel, Rudolf. "Eine Milliarde Jahre geologischer Entwicklung am NW-Rand des Kalahari-Kratons." [S.l. : s.n.], 1999. http://deposit.ddb.de/cgi-bin/dokserv?idn=963612484.
Full textBooks on the topic "Namibia {Geologie}"
1
Grünert, Nicole. Namibias faszinierende Geologie: Ein Reisehandbuch. Windhoek: Kalus Hess Verlag, 1999.
Find full text
2
T, Becker, and Geological Survey (Namibia), eds. The geology of Namibia. Windhoek, Namibia: Ministry of Mines and Energy, Geological Survey, 2008.
Find full text
4
Hoal, B. G. The geology and geochemistry of the Proterozoic Awasib Mountain terrain, southern Namibia. Windhoek, Namibia: Ministry of Mines and Energy, Geological Survey of Namibia, 1990.
Find full text
5
Kukla, Peter A. Tectonics and sedimentation of a Late Proterozoic Damaran convergent continental margin, Khomas Hochland, Central Namibia. Edited by Galloway Clare Kennedy. Windhoek, Namibia: Ministry of Mines and Energy, Geological Survey of Namibia, 1992.
Find full text
6
Jungquartäre Reliefentwicklung, Substratgenese, Klimageschichte und aktuelle Morphodynamik am Ostrand der Namib in der Region Hartmannstal-Marienflusstal (NW-Namibia). Köln: Geographisches Institut der Universität zu Köln, 2007.
Find full text
7
Brigitte, Senut, and Geological Survey (Namibia), eds. Karst geology and palaeobiology of northern Namibia. Windhoek, Namibia: Ministry of Mines and Energy, Geological Survey of Namibia, 2010.
Find full text
8
Ziegler, U. R. F. Age determinations in the Rehoboth Basement Inlier, Namibia. Windhoek, Namibia: Geological Survey of Namibia, Ministry of Mines and Energy, 1993.
Find full text
9
Namibia--fascination of geology: A travel handbook. Windhoek: Klaus Hess Publishers, 2000.
Find full text
10
Brigitte, Senut, and Geological Survey (Namibia), eds. Geology and palaeobiology of the Northern Sperrgebiet, Namibia. Windhoek, Namibia: Ministry of Mines and Energy, Geological Survey of Namibia, 2008.
Find full textBook chapters on the topic "Namibia {Geologie}"
1
Cartwright, Joe, Roger Swart, and Branko Corner. "Conjugate margins of the South Atlantic: Namibia-Pelotas." In Regional Geology and Tectonics: Phanerozoic Passive Margins, Cratonic Basins and Global Tectonic Maps, 202–21. Elsevier, 2012. http://dx.doi.org/10.1016/b978-0-444-56357-6.00005-6.
Full text
2
Spivey, M., A. Penkethman, and N. Culpan. "Geology and Mineralization of the Recently Discovered Rössing South Uranium Deposit, Namibia." In The Challenge of Finding New Mineral ResourcesGlobal Metallogeny, Innovative Exploration, and New Discoveries. Society of Economic Geologists, 2010. http://dx.doi.org/10.5382/sp.15.2.17.
Full text
3
Abrahams, Peter W. "Human Geophagy: A Review of Its Distribution, Causes, and Implications." In Geology and Health. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195162042.003.0010.
Full textAbstract:
Geophagy (or geophagia) can be defined as the habit of eating clay or earth, a practice about which there is a great deal of misunderstanding. Though many people know and accept that geophagy is undertaken by wild and domesticated animals, and that humans can inadvertently ingest soil by (for example) hand-to-mouth activity, the deliberate consumption of soil by humans appears to be more difficult to comprehend. Yet geophagy (or pica) is a widespread among contemporary nonhuman primates (Krishnamani and Mahaney 2000), suggesting that the practice predates human evolution, and that soil ingestion has continued for a multiplicity of reasons. Therefore, although words such as ‘evil,’ ‘odd,’ ‘filthy’ and ‘degrading’ have been applied to geophagy as practiced by humans, a more enlightened appraisal is to suggest that soil consumption should be considered to be within the normal range of human behavior (Vermeer 1986). The oldest evidence for human geophagy comes from a prehistoric site at Kalambo Falls where the bones of Homo habilis, the immediate predecessor of Homo sapiens, have been found alongside a white clay believed to have been used for geophagical purposes (Root-Bernstein and Root- Bernstein 2000). Human migration then transferred geophagy to other parts of the earth, although Laufer (1930) concluded that the practice is not universal, being unknown in some countries such as Japan, Korea, and parts of Africa. To a certain extent this may be attributable to a lack of reporting on geophagy. For example, although the practice is not recorded in Namibia by Lagercrantz (1958, Figure 1),Thomson (1997) reports that the deliberate consumption of soil is commonly undertaken by pregnant women in the eastern Caprivi region of the country. Geophagy can still be found relatively easily throughout many societies of the world today. While investigating geohelminth (i.e., parasitic worm) infection and mineral nutrient deficiencies in children and pregnant women, Geissler et al. (1997, 1998) indicated the prevalence of geophagy in parts of Kenya. In these studies, 73% of 285 school children aged 5-18 years indulged in the practice, whereas 154 of 275 pregnant women (56%) reported eating soil regularly.
Conference papers on the topic "Namibia {Geologie}"
1
Gomez, Cecile. "Potentials and limitations of coupling ASTER and airborne geophysical data for improvement of geological mapping in arid region (Namibia, Rehoboth region)." In Remote Sensing for Environmental Monitoring, GIS Applications, and Geology III. SPIE, 2004. http://dx.doi.org/10.1117/12.510492.
Full text