Geomorfologia e neotectônica no Vale do Apodi-Mossoró RN

Numerous studies have indicated that the Potiguar Basin is affected by Cenozoic tectonics. The reactivation of Cretaceous fault systems affect the post-rift units, witch include Neogene and overlying Quaternary sediments. In this context, the objectives of this thesis are the followings: (1) to characterize the effects of post-rift tectonics in the morphology of Apodi Mossoró-river valley located in the central portion of the Potiguar, (2) to characterize the drainage of the Apodi Mossoró river valley and investigate the behavior of their channels across active faults, and (3) to propose a geologic-geomorphological evolutionary model for the study area. This study used a geological and geomorphological mapping of the central part of the basin, with emphasis on the Quaternary record, luminescence dating of sediments, and geoelectric profiles of the area. The results reveal by maps of structural lineaments and drainage channels of the rivers form valleys that are affected by faults and folds. In Apodi-Mossoró valley, anomalies of channel morphology are associated with the deformation of the post-rift basin. These anomalies show the reactivation of major fault systems in the Potiguar Basin in Cenozoic. On a regional scale, can be seen through the vertical electric profiles that the Cenozoic tectonics is responsible for the elevation of a macro dome NE-SE-trending 70-km long and 50km wide and up to 270 above sea level. In this sector, the vertical electric profiles data show that the contact between the Cretaceous and Neogene rise more than 100m. This Is an important feature of inversion data obtained in this work showed that the deposits that cover the macro dome (Serra do Mel) have ages of 119 ka to 43 ka. In the river valley and surrounding areas Apodi-Mossoró ages vary between 319 ka and 2.7 ka. From these data it was possible to establish the correct geochronological posiconamento paleodepósitos of distinguishing them from the fluvial deposits of the Neogene (Barreiras Formation)

As dunas eólicas de Natal/RN: datação e evolução

The main purpose of this study is to present complementary information on eolian systems that occur in the Center-South portion of the city of Natal, Rio Grande do Norte State, Brazil. The investigation focused on the identification of eolian units, absolute luminescence dating of eolian sediments, to geophysical analysis by Ground Penetrating Radar (GPR), as well as qualitative identification of the use and terrain occupation in the study area. A map was elaborated in order to separate eolian geological units, and describe their deposicional and erosional characteristics, by aerial photo-interpretation. The study lead to the identification of six main units: Unit I - Blowouts (BW), Unit II - Active dunes field (DA), Unit III - Fixed dunes field (DF), Unit IV - Parabolic dunes field (DP), Unit V - Red parabolic dunes field (DV) and Unit VI - Devastated dunes surface (SD). Were analised by Termoluminescense (TL) Method Eight samples from units I, III, IV and V. The largest number of samples with similar or close resulted yielded ages about 15,000 years. Two GPR profiles were obtained in areas of the Dunes Park, near the "Natal s Conventions Center". Results showed the migration a new dune generation over on older one, the geologic contact between dunes and the Formação Barreiras (FB), and the groundwater level inside the dune unit. The qualitative study on the use and terrain occupation of the soil in some dunes fields in the study area, it was possible identify some use and occupation, as the following ones: the construction of residential and commercial buildings, dunes fields cutted for construction to access road and garbage deposition

Estudo evolutivo das condições ambientais da região costeira do município de Guamaré - RN

The work concerns on the evolutionary study of the environmental conditions of the coastal area of Guamaré-RN, where was investigated the geo-environmental transformation occourred in this region, whose primordial purpose was to diagnose the changes verified in the temporary space of five decades (1950 to 2001). With the objective of evaluanting the action of the active coastal processes (currents, waves, tides and winds), in order to understand the generating mechanisms of the erosion/sedimentation, evidenced by constant morphologic changes. The adopted methodological procedure consisted of a succession of stages, involving bibliographical and cartographic study, aereal photographs study, digital treatment of images, field work (sample collection, beaches profiles, characterization of the beach environment and morfodynamics), mapping correction and laboratory analyses (granulometry). The evolutionary study of the morphologic features indicated significant variations in the studied period, mainly, in the dunes, sea terraces, variation of the shore line and tidal flat, evidencing the largest transformations in the temporary space between 1988 and 2001. The analyses of the beach profiles showed a sedimentation tendency in the area of the profiles P1, P2 and P3, however in the monitored pediod, it was observed in the referred profiles, erosive and depositionals intervals evidencing a need of more effective monitoring. The results of the granulometric analyses indicate a predominance of mean to coarse sand in the backshore and estirancy area, as in the shoreface, the analyses indicated medium to fine sand. The morfodynamic state, showed that beach of Minhoto is intermediate state, with alternancy to reflective. The areas of larger vulnerability and sensibility are the tidal flat, shore line, barrier island and mobile dunes, that actually is suffering great environmental impact with expansion of the carcinoculture, urban presence and natural impacts (erosion of the shoreline)

Análise multitemporal dos elementos geoambientais da região da Ponta do Tubarão, área de influência dos campos petrolíferos de Macau e Serra, município de Macau/RN

The study area is inserted in Ponta do Tubarão region, Macau City, setentrional littoral of Rio Grande do Norte State, composed of Tertiary and Quatemary sedimentary rocks and sediments. This region is characterized for the intense action of the coastal processes, causing the morphologic instability in part of the area, beyond the interference of human activities, as the Petroliferous Industrial Polo, salt companies and shrimp farms. This justifies the integration of multidisciplinary and multitemporal detailed scientific studies dealing with the evaluation of the changing behavior of this coastal environment by geoenvironments elements characterization, identifying protected and recuperation areas, mainly those under socioeconomic intervention. The main objective was the coastal monitoring using geoprocessing techniques to prepare thematic maps useful for oil spilling environment risk areas survey. The methodology was based on multitemporal interpretation of remote sensing images and field checking, integrated in a Geographical Information System (GIS). The Geologic, Geomorphologic, Vegetation, Soil and Land Use maps were prepared, and later on they allowed the generation of the Natural Vulnerability and Environmental Vulnerability maps. These maps had been classified in accordance with vulnerability degrees: very low, low, medi um, high and very high. Beyond these maps the GIS allowed the analysis of the shoreline evolution for 10 distinct dates, using Landsat 5 TM and 7 ETM+ and SPOT-HRVIR images. This analysis made possible the attendance of the coastal morphodynamic evolution, where the results had been represented by areasof erosion and accretion (or deposition) of sediments, pointing critical areas under erosive process to the petroliferous industry (Macau and Serra fields). The GIS also provided to prepare the Environmental Sensitivity Maps of Oil Spill (SAO Maps) in operational scale (1: 10.000), according to the norms ofthe Ministério do Meio Ambiente (MMA 2002). The SAO Map in operational scale was based on IKONOS images mosaic where the ESI (Environmental Sensitivity Index) was represented according with two tides phases of theregion. Therewere recognizedfiveESI (3, 4,7,9, 1O) for the low tide; to the high tide the ESI number increased to seven (3, 4, 5, 7, 8, 9, 10). All these information are necessary to the decisions making about oi! spill and its derivatives containment. These techniques application makes possible the optimization and implantation ofnew socioeconomics activities of low environmental impact, indicates areas for better productivity and security exploration, and benefits local communities with fauna and flora preservation. The development of these activities is inserted in the scope of Monitoramento Ambiental de Áreas de Risco a Derrames de Petróleo e Seus Derivados Cooperation Project (Rede 05/01 - PETRORISCO, FINEP/CTPETRO/PETROBRAS) of multidisciplinary and interinstitucional characteristics dealing with subjects involving the environmental monitoring and the petroliferous activity

Caracterização geológica, geomorgológica e geotécnica de um corpo de dunas na cidade de Natal-RN

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Sistemas de dunas do parque das Dunas e Barreiras do Inferno/Natal (RN: levantamento geológico /geofísico, elaboração do modelo deterministico e avaliação da vulnerabilidade/suscetibilidade

The current work was developed on the dune systems of the Parque das Dunas and Barreira do Inferno. These places are located in the cities of Natal and Parnamirim (RN, Brazil), respectively. This project has the purpose of developing the deterministic model on a specific blowout at Parque das Dunas, based in the geophysical interpretations of the lines gotten with the Ground Penetration Radar and the planialtimetric acquisitions of the topographical surface of the land. Also analyses of the vulnerability/susceptibility of these dune systems had been done in relation to the human pressures. To develop its deterministic model, it is necessary to acquire inner and outer geometries of the cited blowout. In order to depict inner geometries underneath the surface are used the GPR observing the altimetric control for topographical correction of the GPR lines. As for the outer geometries, the geodesic GPS gives us the planialtimetric points (x, y and z points) with milimetric precision, resulting in high-resolution surfaces. Using interpolation methods of the planialtimetric points was possible create Digital Elevations Models (DEM´s) of these surfaces. As a result, 1,161.4 meters of GPR lines were acquired on the blowout at the Parque das Dunas and 3,735.27 meters on the blowout at the Barreira do Inferno. These lines had been acquired with a 200 MHz antenna, except the 7 and 8 lines, for which we had been used a 100 MHz antenna. The gotten data had been processed and interpreted, being possible to identify boundary surfaces of first, second and third order. The first order boundary surface is related with the contact of the rocks of the Barreiras Group with the aeolian deposits. These deposits had been divided in two groups (Group 1 and Group 2) which are related with the geometry of stratum and the dip of its stratifications. Group 1 presented stratum of sigmoidal and irregular geometries and involved bodies where the reflectors had presented dips that had varied of 20 to the 28 degrees for the Parque das Dunas blowout and of 22 to the 29 degrees for the Barreira do Inferno blowout. Usually, it was limited in the base for the first order surface and in the top for the second order surface. Group 2 presented stratum of trough, wedge or lens geometries, limited in the base for the second order vi surface, where the corresponding deposits had more shown smoothed reflectors or with dips of low angle. The Deterministic and Digital Elevation Models had been developed from the integration and interpretation of the 2D data with the GOCAD® program. In Digital Elevations Models it was possible to see, for the localities, corridor or trough-shaped blowouts. In Deterministic Model it was possible to see first and second order boundary surfaces. For the vulnerability/susceptibility of the dune systems it was applied the methodology proposal by Boderè al (1991); however the same one did not show adequate because it evaluates actual coastal dunes. Actual coastal dunes are dunes that are presented in balance with the current environmental conditions. Therefore, a new methodology was proposal which characterizes the supplying and activity sedimentary, as well as the human pressures. For the methodology developed in this work, both the localities had presented a good management. The Parque das Dunas was characterized as a relic dune system and the Barreira do Inferno was characterized as a palimpsestic dune system. Also two Thematic Maps had been elaborated for the environmental characterization of the studied dune systems, with software ArcGis 8.3, and its respective data bases

Estudo da dinâmica costeira da região da foz do rio Piranhas-Açu para geração de mapas de sensibilidade do litoral ao derramamento de óleo

The study area is located in the northern coast of Rio Grande do Norte State comprising the mouth of Açu-Piranhas river including the cities of Porto do Mangue e Areia Branca. The local geological setting comprises Cretaceous, Tertiary and Quaternary geological units of the Potiguar Basin. One is about a region of high morphologic instability due to action of the rigorous dynamic coastal processes, beyond the intense human activities mainly for the performance of the petroliferous industry, salt farms and tanks of shrimp industry.For the accomplishment of this work Landsat 5 TM and Landsat 7 ETM + from four distinct dates were used as cartographic base, in which one applied techniques of digital processing to elaborate thematic maps of the existing natural resources to support the geologic and geomorphologic characterization and the soil and landuse maps. The strategy applied was the interpretation of multitemporal images from aerial and orbital remote sensors alIied to the terrain truth recognition, integrated through a Geographic Information System. These activities had alIowed the production of Sensitivity Maps of the Coast to Oil Spilling for the area, on the basis of the Coastal Sensibility Index. Taking into account the seasons were created maps to distinct datas: July 2003 represents the winter months that presented a sensibility lower when compared with the month of December 2003. For the summer months greater sensitivity is due to the hydrodynamic data that suggest a lesser capacity of natural cleanness of the oil and its derivatives in spilling case.These outcomes are an important and useful database to support an assessment to a risk situation and to taking decision in the face of an environmental disaster with oil spilling in coastal area, alIowing a complete visualization of the area and identifying all portions in the area with thei environmental units and respective Coastal Sensibility Index.

Caracterização morfodinâmica do estuário do Rio Açu, Macau/RN

Estuaries are coastal environments ephemeral life in geological time, derived from the drowning of the shoreline as a function of elevation relative sea level. Such parallel systems is characterized by having two sources of sediment, the river and the sea. The study area comprises the Acu River estuary, located on the northern coast of Rio Grande do Norte State, in a region of intense economic activity, mainly focused on the exploration of oil onshore and offshore, likely to accidental spills. In the oil sector are developed for salt production, shrimp farming, agriculture, fisheries and tourism, which by interacting with sensitive ecosystems, such as estuaries, may alter the natural conditions, thus making it an area susceptible to contamination is essential in understanding the morphodynamic variables that occur in this environment to obtain an environmental license. Information about the submarine relief the estuaries are of great importance for the planning of the activity of environmental monitoring, development and coastal systems, among others, allowing an easy management of risk areas, and assist in the creation of thematic maps of the main aspects of landscape. Morphodynamic studies were performed in this estuary in different seasonal periods in 2009 to observe and quantify morphological changes that have occurred and relate these to the hydrodynamic forcing from the river and its interaction with the tides. Thus, efforts in this area is possible to know the bottom morphology through records of good quality equipment acquired by high resolution geophysical (side-scan sonar and profiler current by doppler effect). The combination of these data enabled the identification of different forms of bed for the winter and summer that were framed in a lower flow regime and later may have been destroyed or modified forms of generating fund scheme than the number according Froude, with different characteristics due mainly to the variation of the depth and type of sedimentary material they are made, and other hydrodynamic parameters. Thus, these features background regions are printed in the channel, sandy banks and muddy plains that border the entire area

Feira livre de Macaíba/RN : um estudo das modificações na dinâmica socioespacial (1960/2006)

The objective of the current piece of research is to reflect upon the diverse changes that have occurred in the social and spatial dynamics of the Macaíba fair in the period between 1960 and 2006. During the second half of the 19th century, Macaíba had in the commerce one of this principle economic base a contribution for which the city became one of the main commercial warehouses of the East coast of the Rio Grande do Norte region. This helped lead to the growth of Macaíba s fair, which proved to be one of the most important existing in the state until the 1970 s. In the last two decades of the 20th century, certain elements represented challenges to the fair at Macaíba. These challenges stimulated substantial changes in the fair s dynamics which include the growth and expansion of the commercial and service sector, primarily though supermarkets; consolidation among the commercial and distribution networks, represented by the Central Office of Supply of the Rio Grande do Norte S/A (Ceasa/RN), by the wholesale and refrigeration companies; and the modernization of transportation methods, which permitted an expanded reach for these networks. Even with all these changes, the fair continues to be one of the strongest aspects of the city being the center of resistance against the surge of new forms of commerce and consumption in the city (notable the supermarkets) and the diffusion of other aspects of globalization. The fair has economic importance, as it offers a popular marketplace for the commercialization of very different products and a means for supplying goods to the residents of the city and the rural communities of Macaíba and the surrounding municipalities; and socio-cultural importance in that the fair is a place where popular tradition is expressed, a place where a great number of parallel activities occur, a place for meeting again and again, of conversations, of manifestations of culture and art, and of socialization in all of its dimensions

Dinâmica do uso e ocupação do solo no litoral de Macau-RN no período de 1978 a 2008

This study was developed in the northern coast of the city of Macau, a total area of 88,52 km², located in the State of Rio Grande do Norte. It presents relatively plain surface, with interlaced of streams and gamboas, characterized by contributions of oceanic water, flooding areas of swamps. Altogether, the climatic and topographical conditions provide an ideal environment for the development of saline activity. Inserted in the geologic context of the Potiguar Basin, the region presents favorable conditions for the production of hydro-carbons. It still presents natural conditions for shrimp breeding and artisanal fishing. This work analyzes the transformations occurred in the land use, using air photographs of 1978, Landsat 5 ETM Images of 1988, 1998 and 2008. A secular analyzes was carried through the dynamics of the use of the territory and the transformations occurred in the landscape due to the increment of the productive activities. In the survey of the data for study of the area, it was verified that little alteration occurred in the 30 years. The saline activity that was present since the year of 1978 having an increase of about 5% in thirty years; the shrimp breeding activity that had its presence in the decade of 1990, presented a high growth in the land use, therefore in 1998 it presented 0.45% and currently it presents 6.59%. In the field it was observed that great areas used previously for the saline activity, today it is prepared for shrimp breeding and that the areas of petroleum exploration occupy salt mines, beaches and trays. In 1988 it presented a percentage of 0, 07% and currently it occupies 0.46%, having grown 50% in the last 10 years. Although the variation of the occupation of the area has been little expressive, shrimp breeding showed a growth of 1,200% in only 10 years. In regards to petroleum activity, there wasn t any demonstration of an increasing impact in the land use in the area of study in 26 years of exploration

Estudo multitemporal da dinâmica espacial do estuário Potengi/RN, utilizando como base os dados de Sensoriamento Remoto.

This work was developed in the Potengi river estuary, northern coastal city of Natal, located in the State of Rio Grande do Norte. The objective was to study the dynamics of Multitemporal Space in that estuary, however, analyze how this environment has behaved during the years 1988, 1994 and 2006. The definition of that, there was the fact that during that period, which occurred in that area and more intensive space exploration to practice economic activities as well as a greater and more rapid expansion of urban area. This study was supported by the Remote Sensing, who have been shown today, as an efficient analysis of the environmental studies, through geoprocessing techniques. From the performed analysis it was found that occurred during the period of study (1988 to 2006), a huge change in the design of the estuary of Potengi river. The figures showed the area of vegetation was decreased 65.22%, the deforested area increased by 70.44% and the shrimp activity grow 452.07% and the urban area was increased in 52.65% along that period described. Considering the numbers shown there that the process of occupying space in that area requires attention, because it is an environment that represents a huge contribution to the ecological balance.

A reafirmação do bairro:um estudo geo-histórico do bairro do Alecrim na cidade de Natal-RN

By the end of the 21st Century, economy globalization trends to show a velocity process through which market being expanded characterized by an intense going on of the internationalization of finance, after that marginalizing the periphery of the social spaces. It is clear to see that this process occurred in those less developed countries happens in an accentuated way just because income distribution that is so regressive and also because the insufficient enclosing of the social programs, we find this situation in a big part of Brazilian cities. The marginalizing social economical process observed in Natal, a city located in the east coast part of Northeast region in Brazil and that owns a population upper to 778 thousand in habitants is nearly linked to the extension of goods and services commerce. The installation of new urban activities in the city pointed out tourist activity as the greater impulsive thing in the phenomenon promotion, most of them aiming to promote Natal to the national and international scenery. It privilege strongly in the South zone with economical implementations such as shopping s centers, supermarkets, and home buildings condominiums leading to a loss of functionality of some traditional district located in central areas of the city. Notwithstanding, some spaces, for instance Alecrim district officially created in 1911, has notably resisted to the expansion of the urban process pointed out in Natal in the last years. So that this put Alecrim District as a district with originally characteristics reaffirmed along the historical process form old times. The predominance of some residential characteristics such as the incidence of some villages and a concentration of a big and confuse popular commerce distributed along streets puts Alecrim District as a resistant space in Natal. The same way analyze Alecrim District under the prism of Historic Geography because we understand this way it accomplishes a fundamental role in the theoretical methodological development of our work, just when we analyze the time as a variant in our object of study. It is still inside this theoretical field that we carry out a brief reviewing about quarter/district definition, under the optic from several registered and scientific resources taken into account along this work, because we understand that it was necessary to think this important spatial unit especially to know exactly what we are referring to as a district and so we can reaffirm Alecrim as an important and traditional district to Natal and it has been resisting to spatial transformation verified in the last years in Natal city. To give support to our reflection we used methodological tools related to inhabitants lifestyles knowledge and also the study of Alecrim District as a space that promote a certain centrality in Natal as some indicators to keep original characteristics in the district in Natal

Reprodução do capital e metamorfoses espaciais : um estudo da verticalização de Ponta Negra, Natal/RN

The broach presented in this dissertation, linked to post graduate Geography´s of the Universidade Federal do Rio Grande do Norte - UFRN, more exactly about the research group entitled interdisciplinary studies unit on space and housing built . The research developed through this study has this central theme on vertical grounding of the construction in the neighborhood of ponta negra in Natal, Rio Grande do Norte. Realizing this momentum as a way of accumulation of capital in city. Rio Grande do Norte´s city. During the 2000 s , the neighborhood of Ponta Negra went through an intense process of vertical integration of its ground, Provided by many factor of conditions created from new economic, political and social functions which start to be outlined mainly from the tourism development in this neighborhood since the 80´s decade. The Tourism development and the landing planning of the ponta negra´s neighborhood promoted for the government by using order to police the city´s urbanization, beyond the sense of the civilian building actors. They enabled this neighborhood to become propitious to the real estate investments. Many ventures were built before the year of 2010 while another are on building, which, over the years, changed the sociospatyal dinamics of the neighborhood. Considering the urban space is socially built, product and condition for the reproductive process of the capitalist society, the goal of this research is to investigate the verticalization of the ground, for capital reproduction purposes. This research aims to analyze the vertical this quarter through the theory of social production of space by Henri Lefebvre. The Methodology adopted pervades for secondary and primary research, compound for bibliographic research, documentary, journal, magazines, camp research and interview, to reach the best way to analyse the dynamics of the refered neighborhood

Inferência geográfica para delimitação de corredores ecológicos: um estudo de caso para a Mata Atlântica do município de Tibau do Sul/RN

The Atlantic Forest biome occupies much of the Atlantic coast of Brazil, in addition to portions of Paraguay and Argentina. Due mainly to its biodiversity which falls in the group of global hotspots, i.e., areas that have high priority for conservation. Although currently there are some available devices that assist in their protection in the course of the history of occupation and exploitation of the Brazilian territory, this biome has gone, and is still going through, an intense process of devastation, caused mainly by the pressure from economic activities, culminating in a significant reduction of its area and consequent fragmentation of the landscape, which brings with hosts a series of problems at various scales and aspects. As in most municipalities included in the reach area of the biome, the situation of forest fragmentation in Tibau do Sul / RN is quite critical, reflecting on a truly diverse landscape with broad typology of land uses. Among the alternatives aimed at the conservation of this biome include the creation of protected areas and the creation of ecological corridors, the latter being more efficient by connecting the remaining forests, increasing landscape connectivity, providing significant gains in relation to biodiversity. However, a major problem on implementation of Ecological Corridors projects is related to the selection of areas for this purpose, in this sense Geography can provide important contributions through the integrated study of landscape in the light of the geosystemic approach and the use of Geographical Information System (GIS) in order to permit assessment of reality having as a base the integration of ecological, biological and man-made aspects. Thus, this research aims to indicate potential areas and propose scenarios delimitation of Ecological Corridors in the municipality of Tibau do Sul / RN through Geographic Inference techniques in GIS platform. Therefore, the methodology adopted is based on the Geosystemic approach. From these elements were created 4 models to indicate potential areas for implementation of Ecological Corridors from the environmental perspective (potential erosion), socioeconomic (cover and land prices), legislative (areas protected by environmental legislation) and integrated (combination of environmental factors, socioeconomic and legislative), which in turn served as a basis for proposing scenarios aimed at this purpose. The results showed that all models can be quite useful in indicating potential areas for the establishment of ecological corridors, especially when based on an integrated approach between environmental and anthropogenic. The Corridors delimitation proposes shown may perform duties beyond the establishment of connectivity between fragments, since they also may have usefulness in controlling erosion and protecting fragile environments. Among the models developed, the integrated constituted itself as the best option because it enabled the interconnection of a larger number of fragments from a better use of the potentialities present in the landscape

Os marcos da paisagem da cidade no contexto da trama urbana de Natal/RN: um estudo a partir do Morro do Careca, o Midway Mall, o Pórtico dos Reis Magos e a Ponte Newton Navarro

The present work is a study on the functions performed by landmarks landscape Natal / RN in the urban fabric, in the case of Midway Mall, the Portico dos Reis Magos, the Morro do Careca and Newton Navarro Bridge. For such goals established itself as analyze the functionality of the milestones presented here in the urban fabric; discuss the importance of these landmarks of the city landscape in the process of urbanization of Natal, and identify and spatialize actions related to the use of territories where are located landmarks, discussing their reflections. To achieve these goals we chose to use as a literature search procedures, the problematic concept, working with oral sources, and reading speechless. To support this research the main concepts were worked landscape, city, landmark, public space, circuits, among others. After going over the theory, consistent with the empirical data, it appears that the landmarks studied here have different functions and features, but all carry different forms of fascination for the public and visitors to the city, and every man your way, influence the public space, land speculation and feature importance in the process of urbanization of Natal