Rio Blanco Basin Research Articles

Lechuguín (Eichhornia Crassipes (Mart.) Solms) y lenteja de agua (Lemna Spp.) en la reducción de la dureza del agua de riego

La contaminación del agua de riego representa uno de los problemas más importantes para la producción agrícola, ya que afecta significativamente a la economía por la pérdida de cultivos, debido a esto la búsqueda de métodos de remediación son muy importantes. El uso de plantas acuáticas representa una técnica alterna como fitorremediación a los métodos físicos utilizados frecuentemente. El presente estudio muestra la reducción alcanzada de la dureza del agua de riego de la empresa Flores del Cotopaxi S.A., para lo cual se utilizó plantas acuáticas como lechuguín y lenteja de agua. Para determinar las características de la muestra de agua de riego proveniente de la cuenca de Río Blanco se analizó antes y después de ser sometidas a tratamiento los siguientes parámetros: pH, conductividad eléctrica, dureza total, nitratos, y sulfatos, de la misma manera se realizó un conteo de ufc/gramo de raíz de cada planta acuática. La investigación permitió concluir que el lechuguín es la planta acuática más idónea en la absorción de minerales, logrando una reducción de 218 a 154 mg CaCO3/l como parámetro de dureza, control de pH en condiciones neutras en un rango de 7.27-6.57, y disminución de la conductividad, nitritos y sulfatos, dado que sus raíces son más fuertes, y según las pruebas microbiológicas realizadas el contenido de microorganismos es mayor.

Reassessment of mid-Carboniferous glacial extent in southwestern Gondwana (Rio Blanco Basin, Argentina) inferred from paleo-mass transport of diamictites

Late Paleozoic glacial diamictites occur in many localities in western Argentina, indicating that the region was strongly affected by glaciation during the mid-Carboniferous (late Serpukhovian–early Bashkirian). In most instances these diamictites are found in steeply walled paleovalley settings in the Andean Precordillera. This study presents new data from a locality north of the Precordillera that suggests an additional, distinct, volume of ice existed in the region during the Carboniferous. The glacigenic diamictites in the Rio Blanco Basin were ultimately emplaced as gravity flows, precluding inferences of paleo-ice volume. Fold nose orientation and soft-sediment groove orientations within the diamictites indicate that the deposits were emplaced from north to south, suggesting that glacial ice was most likely not sourced from the proto-Precordillera at this locality, requiring the need for another ice center to the north of the basin. Diamictite facies indicates that the sediment was initially supplied to the study area by a warm-based glacier.

Holocene glacial variations in Central Patagonia, Aisen, Chile: geomorphological evidences.

During the Holocene, the patagonian glaciers were characterized by geomorphologically registered advances and retreats. This paper presents the geomorphological evolution and evidences of Holocene glacial advances within a segment in Central Patagonia Cordillera. This area will be used as a reference for studying the postglacial paleoclimatic evolution in the southernmost part of South America. The study area is the Rio Blanco basin (45º30’S), located in Central Patagonia (Aisen Region, Chile). Radiometric dating of organic sediments, within terminal moraines, provides preliminary data of two glacial advances. The first one is represented by the Lake Elizalde frontal moraine, which yielded a 14C age of 9.370±50 years BP (10,700 to 10,480 cal. yr BP). According to this chronological age, this glacial event took place in the Early Holocene. This glacial advance, being 100 to 200 years older than that observed immediately south of the study area, on the eastern edge of General Carrera Lake (or Buenos Aires Lake, in Argentina) and approximately 100 years younger than the event recorded in the Puerto Banderas I moraine (Argentino Lake, 50ºS). These results show that the behavior patterns of the Central Patagonia glaciers differ from that observed both in the Lake District (41ºS, Chile) and in the Magallanes District (54°S, Chile), where there are no traces of glacial readvancement recorded during the Early Holocene. After a major retreat to the west, a more recent glacial advance occurred in the Quetro river valley (a tributary river of the Blanco river), at an age prior to 2.250±40 BP (2.340 to 2.150 cal. yr BP), comparable to the cold stage of the Middle Neoglacial, interpreted to have occurred in different parts of Patagonia. Confronting these results with previously published pollen records, we postulate that the cause of both glacier fluctuations is regional variations in the atmospheric temperature and precipitations.

Environmental Management Accounting (EMA) Case Studies in Honduras –an Integrated UNIDO Project

This article describes the outline and main first results of the UNIDO TEST (Transfer of Proven Practices for Environmentally Sound Technologies) program, which uses Environmental Management Accounting (EMA) for setting the baseline for calculating savings achieved by the Cleaner Production approach. The project focuses on the Rio Blanco basin in North Western Honduras and applies an integrated approach for improving industrial water<br />management, pollution reduction and productivity.<br /><br />

Glacial events in Carboniferous sequences from Paganzo and Río Blanco Basins (Northwest Argentina): Palynology and depositional setting

The age and depositional setting of two glacial events recognized in the western basins of Argentina are discussed in this paper. The older one corresponds to diamictites identified in the upper member of the Cortaderas Formation (Visean, Rio Blanco Basin). The glacial sequence consists of shales, dropstone-bearing shales massive matrixrich diamictites, massive clast-rich diamictites, and stratified diamictites, all of them interpreted as deposited in distal glaciomarine settings. Palynological remains recovered from shales interstratified with diamictites were referred to the late Visean Reticulatisporites magnidictyus-Verrucosisporites quasigobbettii Biozone. Younger glacial deposits were studied at the base of the Guandacol Formation (Paganzo Basin) where are made up by clast-poor massive diamictites, clast-rich massive diamictites, stratified diamictites, thinly-bedded dropstonebearing diamictites, rhythmites, dropstone-bearing shales, and barren of dropstone shales. The whole sequence is interpreted as deposited in low-relief proximal glaciomarine environments (morainal banks). The abundant palynological assemblages found in the glacial interval were included in the subzone A of the Raistrickia densa- Convolutispora muriornata Biozone which is considered Serpukhovian-early Bashkirian in age. Palynological remains found in the Cortaderas Formation suggest that the beginning of the Glacial 2 event in Gondwana (according to Isbell’s chronological proposal for glacial and interglacial stages) should be considered late Visean while the end, according to the assemblages recovered from the Guandacol Formation, was not younger than early Bashkirian. Moreover, sedimentological and stratigraphic data suggest the existence of a short interglacial period between the Cortaderas and Guandacol glacial events.

The Gondwanan Carboniferous-Permian Boundary Revisited: New Data from Australia and Argentina

The identification and correlation of the Carboniferous-Permian (Gzhelian-Asselian) boundary within the sedimentary sequences of Gondwana has always been a topic of debate. Type latest Carboniferous and earliest Permian marine sequences are characterised by warm tropical faunas and come from the Uralian Region of Russia and Kazakhstan. Faunas include conodonts and fusulinid foraminiferids which are prime tools for correlation. Such faunal groups are absent from most Gondwanan sequences where reliance for correlations must be placed primarily on brachiopods, bivalve molluscs and palynology. The Western Australian marine sequences, with their contained ammonoids, provide a pivotal link for the dating and correlating of Early Permian Gondwanan sequences with those of the type regions and their palynostratigraphical record is essential for trans-Australian correlations and correlations elsewhere throughout Gondwanaland. New data from the fully cored DM Tangorin DDHl bore hole, drilled in the Cranky Corner Basin, New South Wales, Australia, reveals a sequence of descending faunal zones. The stratigraphically highest zone with Eurydesrna cordaturn, encompasses the Late Sakmarian (Sterlitamakian). The middle zone with Torniopsis elongata, Sulciplica c r a m and Trigonotreta tangorini straddles the Sterlitamakian-Tastubian boundary, with the palynomorphs Pseudoreticulatispora pseudoreticulata high in the zone and Granulatisporites confluens low in the zone. An impoverished fauna with Trigonotreta nov., low in the Granulatisporites confluens Zone, is probably of latest Asselian or Tastubian age. Significant new data from Argentina has revealed marine faunas from below the occurrence of Granulatisporites confluens. These are considered to be of Asselian age. Outcrops of the Tupe Formation, with a marine fauna, at La Herradura Creek in the western Paganzo Basin, San Juan Province, are best regarded as being of mid to late Asselian age. The Tupe Fauna has been recognised as the Tivertonia jachalensis-Streptorhynchus inaequiornatus Zone. Previously, this fauna was considered to be of Late Carboniferous or Stephanian age. Three faunal associations are known from the Rio del Peii6n Formation, Rio Blanco Basin, La Rioja Province. The middle assemblage with Tivertonia, Costaturnulus, Kochiproductus and Trigonotreta, appears to correlate well with the Tupe Formation fauna. The lower assemblage, with Streptorhynchus, Etherilosia, Costaturnulus, Trigonotreta and a punctate spiriferid, as well as indeterminate productids, probably of Early Asselian age. The youngest assemblage includes a species ofRhynchopora that is close to Rhynchopora australasica from the latest Asselian-early Tastubian of Western Australia. The marine biostratigraphical data from Argentina has enabled a much greater understanding of the earliest Permian marine faunas to be achieved - a story that is apparently absent from the other cold and cool temperate regions of Gondwana.

A new Carboniferous brachiopod genus from South America

Azurduya gen. nov. (Brachiopoda: Camarotoechiidae) is described from Early Carboniferous sequences in the Argentine Precordillera and northern Chile. Marine assemblages and the palynoflora associated with this genus suggest a Tournaisian age. The type species Azurduya chavelensis (Amos, 1958) is reviewed and redescribed from material from the type locality. Additional material from equivalent localities in the Rio Blanco Basin (La Rioja and San Juan provinces, Argentine Precordilera) has been used to understand ontogenetic changes as well intraspecific variation. Azurduya cingolanii sp. nov. is proposed.

Early Carboniferous Bivalvia from western Argentina

Gonzalez, C. R., Early carboniferous Bivalvia from western Argentina. Alcheringa 18, 169–185. ISSN 0311-5518. Lower Carboniferous deposits of western Argentina yield invertebrates and plant remains. In the Tournaisian epoch, a transgression from the ‘Pacific’ flooded the Rio Blanco Basin, forming a semi-restricted inland sea. Marine invertebrates of this age comprise the Malimanian fauna, which is based on the Protocanites-Rossirhynchus Assemblage. Eleven species of Bivalvia are here described Palaeoneilo subquadratum sp. nov., Malimania triangularis gen. et sp. nov., Phestia sp., Volsellina? sp. Posidoniella malimanensis sp. nov., Leptodesma? sp., Schizodus sp., Cypricardinia? sp., Edmondia? sp., Sanguinolites punillanus sp. nov., and Vacunella? sp. nov. They are accompanied by gastropods, trilobites, conularids and corals. The Malimanian fauna is regarded as a poorly to moderately varied assemblage that was influenced by some basinal restrictions. It was probably connected to faunas of Chile and Peru, a...