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GEOMORPHOLOGY IMPORTANCE risques geomorphologique. Le geomor- phologie dormer un coupe de main dans le IN THE LAND EVALUATION AT THE ARGENTINA SUBTROPICAL PLAINS genie civil et l'organizationne espádale. Le but de cet article est d'étudier les geoformes de les plaines de l'Argentina subtropical. Eliseo Popolizio L'article emphatique l'utilisation de las pho­ tographies aéries ainsi l'images satelitales. Finement, e'est analyse l'échange climatique Presentado al 9 th Congreso on Engineer­ global et leur consequences sur les plaines ing Geology Developing Countries. LAGE avec les genie civiles. Durban Sudafrica 2002References

The main features of the argentinian east­ Abstract, ern subtropical plains The Argentine subtropical plains are The Argentine northeast region is characterized for a very low relief ampli­ constituted mainly for a wide area of plains. tude. They supports continuos drier and It embraces the Chaco, Corrientes, Formosa floodings periods which are caused by in­ and the south comer of the Misiones Prov­ tense rainfalls or large river floods. In order inces altogether with the north zone of the to detect the risk areas, the geomorphology Santa Fé Province. This area is about constitute one of the main scientific tools for 300,000 km2. The climatic conditions are this study. This discipline is related directly tipically subtropical. The population is about with civil works (dams, bridges, buildings, of four million people. railroads, etc.) and the spatial organization. The aim of this paper is to describe the main The rainfalls increase from west to géomorphologie features and the influence east and the temperature from south to north. of natural risks that overcome either cattle­ Because the unexistence of orographic bar­ rising, urbanization, farming, civil work riers that could difficult the air masses areas. In the paper, we remark the impor­ movements, which generally come from the tance of the aerial photographies and the south or from the north, the increase rain satellite imageries applied to géomorpho­ rates are of a constant gradient toward the logie tasks. The importance of these tools is eastern. its relation to the thematic mappings. On the The predominant vegetation is con­ other hand, it is analyzed the effect of the stituted by forests, savannas and mixed prai­ paleogeomorphology, altogether associated ries. There are large rivers across them: The to oscilating climatic conditions not similar Paraná, The Uruguay and The Paraguay rivers. to the actual ones. Finally, the objective is to The sustainable activities are the agriculture­ have in mind the analysis of serious risks farming and cattle-rising as well as forestation. originated by the global climatic change and On the banks of the Paraná and the Paraguay the anthropic action which are actively act­ rivers there are stablished four large cities called ing over the large Argentine plains in the as Posadas, Formosa Corrientes and Resistencia. last decades. The last two mentioned cities, Resistencia and Corrientes, have actually about of 400,000 peo­ ple. Résumé, The geomorphologic features have a Les plaines subtropicales Argenti­ minimum relief amplitude, about 200 me­ nien sont caractérisé pour une relief trè ters. The lowest rates is placed at the south basse. Les plaines supporte continu périodes and the maximum heights are placed at the d'inondationnes. Le motif de l'inondationnes northeastern comer, near the Misiones Prov­ sont les pluies et la rivière (fleuve) croissant. ince. Le géomorphologie est une excellent disci­ Because of this assemblage of pline pour l'étude de las surfaces avec heights, the study area generally is outstand­

94 ingly considered as a very flat surface, Only in the northeastern comer of the area slightly plunging to the Paranâ-Paraguay (the northeast of the Corrientes Province), rivers. The Paranâ-Paraguay rivers consti­ the relief is a little abrupt and then morphol­ tute the main géomorphologie axis of the ogic features are more significative given subtroplical plains region. them the posssibility to recognize geoforms The large flat surface is not a simple frame­ either in the field or by means of teledetec­ work. On the contrary, behind this appar­ tion methods (IGM, 1990). ently simple definition regarding relief con­ In spite of the very low terrain un­ ditions, there is a great variety of geoforms eveness (or relief amplitude) in the geomor­ and some masked or obscured geologic phology geoforms, they are determinant in structures not well understanding until now. soil formation, vegetation bodies and They have clear morphometric and hidrologic behavioring and so in the spatial genetic differences. Such differences have a occupation and organization of the region. great influence in the spatial stablishment An important topic that should be and its organization (Popolizio, 1989). At necessary remark is the fact that many geo­ the study region, migration begun with forms were originated under very different european citizens on the XVI century. This climatic conditions from the actual ones, at proccess begun with the foundation of the laterly Tertiary ages. City of Corrientes on 1588, and spread to a For this reason, many of these are great region. really considered as 'inheritance geoforms'. To recognize the form of the relief This situation clearly implies that in the case and their bahavioring, it is necessary to de­ we could intend to understand genesis con­ forms the vertical scale about ten times with ditions will be necessary to study the envi­ relation to the horizontal scale. This fact was ronment géomorphologie paleoconditions as early recognized by Dra Pierina Passotti in well as some geologic principles (Popolizio, many papers related with the 'Llanura San- Fernández and Torra, 1996). tafesina' situated a little bit to the south of Finally, we must mention that the our region. full area is related to an inmense sedimen­ Using this method, one meter of tary relief basin very complex and very old. plain uneveness represent about 100 meters The history starts at the Paleozoic era. The compare with an irregular scarpt mountain oldest outcropping rocks are the tholeiithic area. basaltic lavas from the Mesozoic situated at By this manner, we can understood the extreme eastern of the studied area. In general, all the area is covered by Quater­ how a topographic uneveness of about 10 meters originated by an anthrophic em- nary sandy-silty-muddy sediments with bankement of a railroad, may gives place to some outcrops of sedimentary Tertiary beds a floodable area of 10 km of extension. The that outcropping at the abrupt gullies of the fact reside in what the regional slopes are of Paraná and Paraguay rivers. 1/10,000; in other words it is necessary to run a distance of 10 km to obtain an uneve­ Main géomorphologie units ness terrain of only one meter. In Figure 1 was classified the main At the plains area the topographic géomorphologie units of the Northeastern maps are few representative and diagnostic Argentine plains. These units were de- because the equidistance between nivel scripted by the author in earlier studies. (Po­ curves which are 2.5 m; so they result in polizio, 1975b, 1982, 1989). documents wich shows scarce géomorpho­ logie information for precise evaluation.

95 Fig. 1 subunits of third order each one. We'll de­ In this paper, we have had special scribe their features in summary because consideration to the 'Chaquena' and the they were analyzed in detailed in other pa­ 'Mesopotamia' inmense plains areas. pers (Popolizio, Serra and Hortt, 1978, The Chaquena plain is characterized 1980). for a relief that dropped out from the west to We start the description from the the east and embraces three significative 'Chaquena Central Dorsum' which represent

96 the continuation of the 'Santafesino Occi­ dental Dorsum' (Figure 2).

B E R M E JO ’F A N ’ (conoide)

Fig. 2

This unit is related to a basament The colmated uadis are characterized criptodorsum. Its height average is about of for the absence of water currents in surface. 100 meters over sea level and Saenz Pana This picture shows some isolated basins represent the main city in the considered which in the periods of intense rains can be zone. surpassed or connected by means of laminar The 'Chaquena Central Dorsum' is flows. In these cases, they drained toward developed in the first order mayor unit the southeast (Popolizio et al., 1980). called as 'Llanura Occidental del Chaco'. At the east of this subunits extends The mayor surface of this area constitute a the 'Llanura Occidental del Chaco' which flat plain in which it isn't possible to observe comprise two subunits as we can see in Fig­ easily uneveness of terrains. ure 2. The first subunit began just in the limit of the 'Chaquefio Central Dorsum', In spite of, a clear 'dune paleomodel' clearly marked by a topographic terrain un­ formed by a chain of hills derived from very eveness scarpment, with a value of about ten fine sandy, silty accumulation deposits meters. They constitute a lowland area lo­ which can be recognized for their typical cated between two topographic dorsums design. They have a height of about one which dropped out to the SE trend. meter and an average width of about one kilometer each ones. Its prevailing orienta­ The unit is a flat plain with some excep­ tion correspond to the NE-SW trend. tional terrain uneveness which are related to an aeolian paleomodel environment. Also, This morphology elements were cov­ there are great number of floodable areas ered, at early stages, by a very robust forest. which have a trend NW-SE. This give place At present days, it is still possible to define to the so called 'cañadas' and 'esteros' la- many paths of this robust forest but very goonal model (a type of water masses of reduced in extension. The robust forest in scarce deepth and not so extense general is localized between the substruc- tural plains covered by 'fire savannas' and like a lake, and so variable in time between crossed by fluvial paleovalleys which acted drier and more humid conditions like the in the form of 'uadis'. wet season). At the inner part of these hidri- cal geoforms there are an incipient fluvial 97 channel with a scarce capacity of water produced a typical overelevation on the me­ flowing toward lower terrains. dium altitude plains as we can see in the Figure 3. The environment and the presence of 'palms' correspond to a typical phisognomy Over this overelevated sediments a called as 'floodable savannas'. phisognomy of robust forest was settled (Popolizio, 1989, Popolizio et al., 1978). During the periods of great rains the area is almost completelly floodable and the Between a couple of overelevated crevasses mentioned channels only can drained a few ridges a fluvial channel was stablished char­ volume of water toward the Paraná river acterize them by a very wide floodable ar­ valley. For this reason, the exceding of wa­ eas. At these areas, the 'esteros' 'cañadas' and ter flows southward, from the Chaco Prov­ the 'savannas with palms' were strongly in­ ince to the Santa Fé Province. stalled. This phenomenon gives place to a In the Figure 2 we can observe a very wide blanket of water because the un- simple skecht of the geomorphological units existense of well defined fluvial courses corresponding to the 'Llanura Chaqueña'. toward the Paraná river. The geomor- To the east of the Llanura Chaqueña phological obstacle for such incipient rivers another unit is present, the 'Llanuras Aluvia­ (channels) is the main geoform called as les of the Paraná and Paraguay river valley'. 'The Dorso Oriental' which come apart the They present different models developed inmense lowland areas ('Bajos Submeridion­ into its fluvial valleys. So, the Paraguay ales del Chaco geoform') from the 'Paraná river valley presents a typical 'meandering river valley geoform'. This obstacle is con­ design' meanwhile the Paraná river valley stitute by the 'Cuña Boscosa geoform' that has an 'anastomosed model' (an extense makes the waters drops towards south. Then, braided-type flat-river model). the phisiographic assemblage in the 'Bajos Submeridionales of the Chaco' leds the wa­ Both fluvial valleys have a 'meander­ ter to the 'Las Golondrinas system', a little ing trend' in the riverside. A backswamp bit more to the south of the study area which zone as well as fluvial terraces are present finally conected these masses of water with herein like conspicuous géomorphologie the El Salado river. fluvial geoforms. However, the Paraná river valley is extended more widely. If we ob­ The second subunit is other topog­ serve all the Paraná river valley extension, raphic dorsum related to an other criptodor- the geoform resembles a 'labyrinthine model' sum called as the 'Dorso Oriental of Chaco as the result of the existence of paralel wa­ and Santa Fé geoform'. This large unit is ter-courses yahoo-type, older meanders and outstandingly different from the anothers floodable and probable-floodable zones. subunits because they are elsewhere covered by robust forest and a typical dendritic Between the Paraná and the Uruguay drainage model. Herein the courses dis­ rivers is present the 'Mesopotámica Llanura' charges to the Paraná river valley. From the which may be divided into three subunits point of view of geography, this dorsum is (Figure 1). called as 'The Cuña Boscosa'. The easternmost unit correspond to Toward the northeast exists the sub­ the Mesozoic rocks, that is to say, the unit called as the 'Conoides Aluviales of the tholeiithic basaltic lavas of the 'Gera Geral Bermejo and Pilcomayo rivers' (Popolizio, Formation' and the beds of the aeolian sand­ 1989). These subunits are formed by aluvial stone giant desert of the 'Botu Catú Forma­ paleofans originated by the mentioned rivers tion'. Actually, these formations constitute (Bermejo and Pilcomayo) under more drier the 'Serra Geral-Solari Group' following the conditions. This climatic cicle gives place to Argentine geologic nomenclature. a characterized divergent drainage network In this area, the relief is more or less model with frequent crevasses ridges which abrupt given place to different levels of hills.

98 They are the results of the climatic changes, The drainage net is well defined as a oscilations that were recorded from the Up­ characteristic dendritic model. There are, on per Tertiary up to day. An exception is pre­ the other hand, copuliform zones with radio- sent between the Mirinay river and the annular drainage model which are possible Aguapey river which represent a floodable reflect of older paleotorrent systems origi­ area sorrounded by more or less elevated nated in more drier conditions. This fact zones like the case of the Tres Cerros implies that the behavioring was largelly peaks'. They represent older inselbergs of torrentic in the past (Upper Tertiary-Lower- about 190 meters above sea level as is the to-Middle Pleistocene). case of the well known 'Nazareno peak'.

underbrushes

lowland areas older crevasse rivers pseudokarstic processes older crevasse rivers

Fig. 2

In this subunit, the underbrush- the basaltic rocks (Mesozoic) are now pre­ grassland masses are large lly present as well sent near the surface. The deepths of the as some scarce paths of robust forest: open tholeiithic basaltic lavas increase western- or in gallery. The gallery forest is always ward. The surficial sandy-silty-muddy sedi­ related to the fluvial courses. ments are Quaternary and created polige- netic geoforms. The occidental limit is Towards the west there is the 'Depre­ formed by sandy-silty hills of about 10 me­ sión Iberana subunit'. This embraces the ters in height. However, these hills are diffi­ lakes and lagoonal system of the Iberá geo- cult to recognize at the field. All the joint morphologic-depresion, the upper fluvial constitute a close-basin of about 13,000 km2 valley of the Río Corriente and the lowland that discharge in the Corriente river. On the area of the Sarandi-Barrancas which are an other hand, the south sector constitute a incipient river geoform. The north part of great hollowed area with filled fluvial sedi­ this subunit constitute one of the largest ments and so giving place to periodically 'wetlands' of South America. It is character­ floodable zones which finished in fluvial ized for continuous floodable zones, also courses like the Guayquiraró river, a me­ lagoonals and, typical 'floating vegetables dium tributary of the Paraná river valley. masses groups', so called in the region as 'embalsados' (Popolizio, 1981). In some Finally, the last subunit is constitute for the 'Lomas and Planicies Embutidas of the NW cases, these groups constitute true 'floating of Corrientes'. It is situated to the west of the islands'. The subunit commented herein, is 'Depresión Iberana'. It is characterized for a limited at east for a very complex structural 'suite' of sandy-hills, with a typical design of lineament which constitute a perispheric 'fans' with its NE extreme comer located at depresión. There was a time when the Paraná river drained in that depresión and the Ituzaingó village. There are lowland plains between the sandy hills assemblage. 99 This lowland areas are the starting of many ing arenaceous soils. The sandy hills are little courses of water, sometimes with ir­ related to the Tertiary sediments called as regular or lobulated low scarpts, revinement 'Puelchense'. Nowadays, they are called as and gullies. The trend of the sandy-hills are the 'Ituzaingo Formation' which can be suit­ 10 meters over the terrain and the 'pseu- able until the Later Tertiary as well as Early dokarstick' plenomena are one of the more Quaternary. The zone have heavy soils and outstandingly little-to-medium geoform pre­ the vegetation is predominantly underbrush sent at this zone (Popolizio, 1975a, 1976). A or grassland-types with some isolated trees. mixed robust forest and underbrush- At the top of the profile are present the grassland coberture are present with prevail­ Toropi and Yupoi Formations (Figure 4).

hills hills wetlands

Fig. 4

sion with gives the analysts a vertical The géomorphologie influence on the geo­ exagération of the low relief geoforms. In graphical spatial and organization related this manner is more easy to detect little to­ to housing state pographic differences and study masses of The hipothesis of work is that the vegetation (Popolizio & Canoba, 1986). natural risks determines the land rates as well as the spatial organization. The subtropical Argentine plains are characterized for large floodings both plu­ The natural risks are strongly condi- vial or fluvial in origin. These floodings are cionated for the geomorphology. By this mixed with period of very dry seasons. The reason, is absolutally necessary a detailed results of such phenomena is that the an­ knowledge of the geomorphology as well as thropic action under these circumstances the geomorphophisiology ir order to known accelerate erosion processes, specially be­ the main risk that can acted on specific cause the unknowledge of the behavioring of zones. the géomorphologie system and the intensity As we can see, the altitude difference of the men activities. in the low relief of the plains is very little as The recurrence of such processes well as the rates of the general surface incli­ acted directly over the spatial organization nation. Under these conditions, the aerial from the begining of the european housing photography and the satellite images play a state in this region of Argentina. great importance to elucidate the relief form. These studies were done at the Centro de The fluvial routes constituted the Geociencias Aplicadas (UNNE, Argentina), natural ways of colonization. This gives during more than 20 continued years. Tech­ place to the birth of various cities setlement; nical resources used were stereoscopic vi­ i.e. Resistencia, Corrientes, Formosa and

100 Posadas cities which are now head of prov­ tivities. On the other hand, this terrains were inces. Other important cities are Goya, the place for the developed of the main Sáenz Peña, Reconquista and so on. How­ comunication ways. Many medium cities ever, this urbanization by means of european and villages were settled just to these ways. men didn't were simoulstanely so the 'Gran So, this cases gives place to a more high Chaco region' continue occupy by indians density of population and many little piece until well later the XIX century. of grounds were created as well as smallho- der phenomena. The large fluvial ways presents sig­ nificative floodings. When the hydrometric On the contrary, toward the east of rates reach out the maximum, then the whole Corrientes Province, besides the riverside river fluvial valley is covered for the water villages near the Uruguay river, appears masses. In this situations several cities and important population cores settled in the surround villages are floods because, as more high places. For this reason, a very mentioned above, they are completelly set­ important and qualified of cattle-rising ac­ tled into the fluvial valley. tivity was stablished and developed. As a result of the geomorphologic features (very Formosa, Resistencia and Goya are hilly), the comunication ways appears many the cities more affected because they are times as radial nets and commonly acted as located in the fluvial terraces. For this rea­ water divisory line. son, they are encourage in the construction of permanent civil works that can control the The paleotorrent model, mentioned periodic fluvial floodings. However, many above, contribute for the stablishment of places of the cities are just into the fluvial little dams which are useful for the explota- valley and so they are exposed fully to the tion of rise field. The irrigation in these flood phenomenon (Popolizio, 2000). cases acted by gravity. This activity is out­ standingly increasing nowadays. At the Besides the large fluvial floodings, northeastern, the edaphic cobertura, a little the region supports the action of pluvial bit more thickness, gives place to agriculture floodings. They are caused because the very developing which embraces large field of low flat land surface and few natural drain­ tea, 'green mate' and soya bean. age which is high uneflcient for flows out the excess of water masses. The forestation activities are devel­ oped at the major part of the Corrientes This phenomenon occur at the low­ Province. The species more exploted are land areas situated between the 'Conoides pine-trees and eucalypthus. For this reason, Aluviales del Bermejo and Pylcomayo river Corrientes Province are nowadays the sec­ (Figure 1). Also, the pluvial floodings af­ ond largest producer of wood at the Arget- fects the inmense area called as 'Bajos Sub- ina. meridionales' in the Chaco Province, the wetland zones ubicated at the Comentes In the descripted scenario adapted to Province which are outlined by the the centered natural conditions excert for the 'Puelchenses hills' (Figure 4) and the cities and the population cores (villages), 'Sarandi-Barrancas incipient fluvial course at was installed a transport comunication way the south of the 'Depresión del Ibera' (Popo­ unconcordant with the geomorpholocic pre­ lizio, 1981). vailing features. This situation origined many problems in the fluvial natural drain­ Under this circumstances, the ur­ age network because the embankments acted banization is very scarce, given place to like true 'plains dams'. large private properties. The main activities are cattle-rising and, in some sectors the rise In spite of the relative high rates of cultivation's. rainfall, the zone present too a very dry sea­ son, which increase towards the west of the More elevated areas have forest and considered region. Many times is common prairies and customly are dedicated to the dry season for a long periods of time; i.e. agriculture, cattle-rising and forestation ac­ 101 three (common) to seven months (rare). Un­ hand, new illness common at the tropical der the dry season, are very common forest region could attack our subtropical region and savannas fires as well as the burning of because the air masses movements to the the harvest. south carriying infected vectors. We can appreciate that the rural population settled at the elevated places Conclusions (positive arenaceous hills) with minimum flood risk. However, this situation gives The Argentine subtropical plains place to deforestation mainly changing to masked and obscured a great variety of re­ the extensive agriculture. In some cases, lief geoforms. They are characterized for a cattle-rising too was adopted at these zones. very low difference of terrain uneveness and The result was the acceleration of soil ero­ very low flat surface inclinations. sion processes, leaching of soils as well as The use of aerial photographies and ravinements, crevasses and gullies forma­ satellite images enhance greatly the possibil­ tion. ity of reconnaissance of the very low relief The global climatic change seems to geoforms as well as mapping the main geo- affects the region from the 60's and their morphologic domains. effects seems to be overlapping the an­ The geomorpholocic features con­ thropic action, in spite of the temperature trolled strongly the activities as well as the and rainfalls increase tendency. That effect spatial organization typical in the region. might be interpreted as a possible change to The same is applicable for the natural risks more ’'tropical" conditions. related to drier seasons or floodings scenar­ We have been carried out studies on ios. the large fluvial courses, like the Paraná The anthropic action installed impor­ river, seem to indicates an increase in the tant changes in the geomorphologic proc­ system oscilation. If this true, the conse­ esses which altering drainage model systems quences may be greater floodings that the and so causing many problems of water ero­ known nowadays. We have a record of sion. floodings that well can indicate that next pluvial and fluvial floodings may be well The global climatic change can acts seri­ above in the present century. ously in the region either over the natural risks or over the activities and spatial or­ As a result of the system oscilation, ganization. For this reason, this phenomenon although seems contradictory, should be should be get out in consideration for future possible that more dry seasons will be pre­ scenarios that determines the potential use sent in the region, more extense that the and evaluation of the land. This phenome­ known until now. non can affects greatly the rates of the lands, In the case that the global climatic the activities as far as the intrinsic spatial change continue in the time and the predic­ organization. ■ tions for this region really occur, the situa­ tion led to the producers to change the pro­ file of the custom cultives. On the other

References IGM (1990). Cartografía Argentina. Cartas y Mapas, in difffent scales of the República Ar­ gentina. Buenos Aires. Argentina

102 Lotti & Associati (1987). Protección de la ciudad de Goya contra crecidas. Estudio de Facti­ bilidad. Programa de Cooperación Técnica entre la República Argentina e Italia y la Provin­ cia de Corrientes con asistencia Técnica de la Societá di Ingeniería e Lotti & Associati. Roma. Italia Popolizio, E. (1975a). Contribución a la Geomorfogeología de la Provincia de Corrientes. Instituto de Fisiografía y Geología. Facultad de Ciencias Exactas e Ingeniería. Universidad Nacional de Rosario. Serie A. Notas N° 7 y 8. Rosario. Argentina Popolizio, E. (1975b). Las redes de escurrimiento. Centro de Geociencias Aplicadas. UNNE. Serie C Investigación. Tomo 2. N° 2. Resistencia Popolizio, E. (1976). La importancia de los procesos pseudokársticos en las redes fluviales de la llanura. Geociencias VI. Centro de Geociencias Aplicadas. UNNE. Resistencia Popolizio, E. (1982). Geomorphology of the Argentine Northeast. Water International 7. pp 162-177. Laussanne. Zwitzerland Popolizio, E. (1989). Algunos elementos geomorfológicos condicionantes de la organización espacial y las actividades del NEA. Geociencias N° 17. Centro de Geociencias Aplicadas. UNNE. Resistencia Popolizio, E. (2000). Risk of flood to the light of global climatic change in Northeastem Ar­ gentina. Journal of Nepal. Nepal Geological Society. 21: 67-74. Kathmandu Popolizio, E., Canoba, C. (1986). A remóte sensing methodological approach for applied geomorphology mapping in plain areas. Proceedings of Seventh International Symposium on Remóte Sensing for Resources and Development and Environmental Management. ISPRS. Comission VII. Enschede. pp 657-663. Rotterdam Popolizio, E., Serra, P., Hortt, G. (1978). Bajos Submeridionales. Grandes Unidades Geo- morfológicas de Santa Fe. Centro de Geociencias Aplicadas. UNNE. Serie C Investigación. T. 7. Resistencia Popolizio, E., Serra, P., Hortt, G. (1980). Bajos Submeridionales. Grandes Unidades Taxo­ nómicas del Chaco. Centro de Geociencias Aplicadas. UNNE. Serie C Investigación. T. 3. Resistencia Popolizio, E., Fernández, V. R., Torra, R. (1996). Geociencias: Bases Conceptuales y Meto­ dológicas. Revista Nordeste 2a Época. Serie Investigación y Ensayos. Facultad de Humani­ dades. UNNE. Resistencia Popolizio, E. (1981). El estudio del Macrosistema Iberá. As a General Coordinator for the Gobierno de la Provincia de Corrientes en el convenio con la Secretaría de Estado, Transpor­ te y Obras Públicas de la Nación. Vol 24, Tomo II, vol 6. Corrientes.

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