Parana Basin Research Articles

Redescription and Phylogenetic Relationships of the Proterochampsid Rhadinosuchus gracilis (Diapsida: Archosauriformes) from the Early Late Triassic of Southern Brazil

The proterochampsids are small to medium-sized, quadrupedal and probable semi-aquatic reptiles that were part of the evolutionary radiation of Archosauromorpha during the Triassic. The group is restricted to the Middle and Late Triassic of South America with eight nomi - nal species. Rhadinosuchus gracilis Huene was the first described proterochampsid and comes from the late Carnian-earliest Norian of south - ern Brazil. This genus and species is currently the most enigmatic and poorly known member of the group. For this reason we redescribe here its anatomy and discuss its phylogenetic relationships. We found that this species can be distinguished from other proterochampsids and we dismiss the proposed synonymy with Cerritosaurus binsfeldi Price. Our quantitative phylogenetic analysis found Rhadinosuchus gracilis more closely related to Gualosuchus reigi Romer and Chanaresuchus bonapartei Romer than to other proterochampsids, together forming the subfamily Rhadinosuchinae. Characters supporting this assignment include a maxilla with a distinct longitudinal change in slope between lateral and dorsal surfaces, and dorsal surface of nasal and frontal ornamented by ridges showing a radial pattern. In addition, Rhadinosuchus gracilis was recognized as the sister taxon of Chanaresuchus bonapartei based on a lacrimal with an antorbital fossa that occupies almost half or more of the anteroposterior length of the ventral process. The topology of the phylogenetic analysis shows that the Brazilian species do not form a monophyletic clade and favours multiple dispersal events between the Ischigualasto-Villa Union (northwestern Argentina) and the Parana (southern Brazil) basins .

Extending the database of Permian palaeo-wildfire on Gondwana: Charcoal remains from the Rio do Rasto Formation (Paraná Basin), Middle Permian, Rio Grande do Sul State, Brazil

Abstract Macroscopic charcoal has been recovered from a bonebed from the Barro Alto outcrop, Middle Permian (Guadalupian), Rio do Rasto Formation, in the southernmost part of the Parana Basin, Brazil. During this time, a global biotic crisis was taking place and changes in the palaeofloristic composition can be observed. Records of palaeowildfires from the Guadalupian Period are scarce on a global scale. In the Parana Basin low plant diversity, compared to the entirety of Gondwana, persists and just a few plant bearing localities have so far been described from the northern part of the basin. In the studied locality, macroscopic charcoal could be detected in an outcropping bonebed and the occurrence of palaeo-wildfires was confirmed. Besides representing the first palaeobotanical data for the Guadalupian of the southern part of the Parana Basin, the charcoal remains analyzed here are also a significant record of the local environmental conditions during the increase in aridity observed during the Guadalupian and Lopingian in Gondwana. This contributes to the understanding of regional changes that took place during this interval.

Proveniência de zircões detríticos e implicações para a paleogeografia da Formação Furnas no noroeste da Bacia do Paraná

No noroeste da Bacia do Paraná, entre os estados de Mato Grosso e Goiás, ocorrem exposições da Formação Furnas, onde também é reconhecido o Lineamento Transbrasiliano. A partir da análise de mapas magnéticos, definiu-se o arcabouço geológico-geofísico do embasamento da área de estudo, com seis principais domínios separados por 5 lineamentos. O contato entre os domínios da Faixa Paraguai e do Arco Magmático de Goiás é marcado pela principal direção do Lineamento Transbrasiliano na área de estudo. Outros lineamentos que ocorrem associados à direção de deformação da Faixa Paraguai foram identificados como um componente secundário do Lineamento Transbrasiliano. A descrição de afloramentos ao longo da borda noroeste da Bacia do Paraná permitiu o reconhecimento das unidades I, II e III da Formação Furnas. Os dados U-Pb dos zircões detríticos da Formação Furnas apresentaram predomínio de grãos com idades neoproterozoicas (560 - 800 Ma), com idade mínima de 526 Ma, e ocorrência de grãos com idades paleoproterozoicas (≈1750/2100 Ma) e arqueanas (≈2700/2800/3100 Ma). O estudo de proveniência de zircões detríticos da Formação Furnas com determinação de idades U-Pb, associado ao arcabouço estrutural do embasamento da bacia, e a comparação com dados paleoambientais foram a base da avaliação da paleogeografia da porção noroeste da Bacia do Paraná durante a deposição da Formação Furnas. As idades indicam uma importante contribuição neoproterozoica semelhante às idades das rochas do Arco Magmático de Goiás, que associados aos dados de paleocorrentes para noroeste permitem inferir que as rochas do arco constituiriam terrenos elevados, orientados na direção NE-SW.

Palinomorfos de afinidad incierta en la perforación DI.NA.MI.GE. 254 “Paso de las Toscas” (Pérmico Inferior), Cuenca Paraná, Uruguay

An assemblage of palynomorphs (acritarchs, algae, fungi among other constituent elements of uncertain affinity) both autochtonous and reworked from San Gregorio Formation and Melo (well DI.NA.MI.GE. No. 254 “Paso de Las Toscas”), Parana Basin, Uruguay, was analysed in this study. The cisuaralians microfloras are mostly indicative of fresh to mixohaline water environments. Notwithstanding, palynomorphs indicative of marine conditions (mainly Micrhystridium) are registered at 349 and 306 mbbp (San Gregorio Formation), and 282, 241, 168 and 139 mbbp (Frayle Muerto Member). The reworked specimens are restricted to some samples of San Gregorio Formation and a sample in the base of Frayle Muerto Member. The results are in accordance to the depositional setting of the sedimentary units as well as with the sea level changes during the time interval considered.

Taxonomic revision and molecular phylogeny of Gymnocorymbus Eigenmann, 1908 (Teleostei, Characiformes, Characidae).

Characidae, one of the most diverse families of Characiformes and one of the largest clades of fishes in the world, has a complex taxonomic background, with one issue being the placement of various genera, including Gymnocorymbus. Herein, we generate the first molecular phylogeny for the genus using three nuclear and two mitochondrial loci and review the systematics of Gymnocorymbus. This genus includes the black tetra, a well-known and popular species among aquarists. Molecular phylogeny strongly supports the monophyly of Gymnocorymbus, with this hypothesis corroborated by the presence of three morphological synapomorphies. Of the six previously known nominal species of Gymnocorymbus, three are considered valid herein: Gymnocorymbus bondi from the Río Orinoco basin, Gymnocorymbus ternetzi from the Rio Paraguay basin, and Gymnocorymbus thayeri from the Corantijn and Amazon basin and rivers of northeastern Brazil. A fourth species, Gymnocorymbus flaviolimai sp. n., is described from the Rio Madeira, Amazon basin. Lectotypes are designated for G. ternetzi and G. thayeri. Our results support previous hypotheses of the alignment of Gymnocorymbus close to the subfamily Stethaprioninae and also support the sister relationship between G. ternetzi and G. thayeri, and of that clade as sister to G. bondi.

A morphological and molecular study of two species of Raphidascaroides Yamaguti, 1941 (Nematoda: Anisakidae), parasites of doradid catfish (Siluriformes) in South America, with a description of R. moraveci n. sp.

Nematodes of the genus Raphidascaroides Yamaguti, 1941 parasitising doradid catfishes (Siluriformes: Doradidae) in Brazil were studied based on morphological and molecular evaluation of newly collected material. A new species, Raphidascaroides moraveci n. sp., is described from the intestine of Platydoras armatulus (Valenciennes) from River Miranda, River Paraguay basin, Pantanal, Mato Grosso do Sul. The new species differs from all of the congeners in having short spicules (163-217 μm in length) representing less than 1% of the total body length and in the posterior region of cloacal opening covered by small rudimentary spines. In addition, it differs from the other congeneric species in the number and arrangement of the caudal papillae and the structure of lips and tail. Raphidascaroides moraveci n. sp. is the third species described from freshwater fishes and the second one in the Neotropical Region. New morphological data on R. brasiliensis Moravec & Thatcher, 1997 from Megalodoras uranoscopus (Eigenmann & Eigenmann) and Platydoras costatus (Linnaeus) (both new host records) from River Xingu, River Amazon basin, Pará, are provided including scanning electron micrographs of taxonomically important structures. The differentiation of the new species is supported by molecular data (partial sequences of the small and large subunits of the rRNA gene).

A Formação Serra Alta, Permiano, no centro-leste do Estado de São Paulo, Bacia do Paraná, Brasil

A individualização e o mapeamento da Formação Serra Alta no Estado de São Paulo sempre foi motivo de controvérsia na comunidade geológica. Apesar de apresentar extensão comparável à Formação Irati em subsuperfície, a unidade ainda carece de estudos mais acurados acerca de seu posicionamento estratigráfico, conteúdo fossilífero, sistema deposicional e idade. Na região centro-leste do Estado de São Paulo, a Formação Serra Alta sucede estratigraficamente a Formação Irati, sendo constituída por depósitos pelíticos cinza escuros. A unidade é mapeada desde o limite sul do estado até o Domo de Gibóia, no Município de Rio das Pedras. Neste local, as formações Serra Alta e Teresina são substituídas pelos depósitos pelíticos da Formação Corumbataí, que se estende para norte, além do limite do Estado de São Paulo, e pode ser considerada unidade correlata a estas. Neste estudo, são apresentadas seções colunares e caracterizados os contatos da Formação Serra Alta com as formações permianas verticalmente contíguas. É apresentada também detalhada análise de fácies, com a finalidade de caracterizar o sistema deposicional. A análise de perfis de sondagem possibilitou também melhor compreensão dos padrões arquiteturais da Formação Serra Alta, auxiliando na determinação de sua real distribuição e posição estratigráfica na porção centro-sul do estado. A integração das informações obtidas permitiu identificar tendências de empilhamento transgressivo particulares, contribuindo para o detalhamento da sucessão predominantemente regressiva em que se depositaram as unidades permianas da Bacia do Paraná.

Ecomorphology and diet reflect the spatial segregation between two Siluriformes species inhabiting a stream of the Bodoquena Plateau, in Central Brazil

Pimelodella taenioptera Miranda Ribeiro, 1914 and Imparfinis schubarti (Gomes, 1956) are two of the most common fish species in Bodoquena Plateau streams, Paraguay basin. These species have benthic habits and subaquatical observations suggested that they present differentiation in their preference for mesohabitat types. Pimelodella taenioptera shows preference for slow waters, such as pools, while I. schubarti is associated to riffles. In this study we investigated if the known patterns of mesohabitat use of P. taenioptera and I. schubarti can be predict by their ecomorphological and trophic traits. We described the dietary habits and ecomorphological attributes of P. taenioptera and I. schubarti individuals, captured in the Parque Nacional da Serra da Bodoquena (PNSB), Mato Grosso do Sul state, central Brazil. Pimelodella taenioptera presented a more generalist diet, consuming a total of 23 different food items. Imparfinis schubarti have a diet based exclusively on aquatic insects. The ecomorphological analysis revealed that the species differed in relation to five morphological traits associated to habitat use (p <0.01). The results of this study reveal a clear functional dissimilarity between P. taenioptera and I. shubarti. The observed trophic and ecomorphological patterns are congruent with the known habitat use for these species and probably reflect the spatial and temporal variability on conditions and resources present in riffles and pools. Therefore, as expected, the morphological and feeding attributes represent predictive information related to mesohabitat use.

First record of the camboatá Megalechis picta (Müller & Troschel, 1849) (Siluriformes: Callichthyidae) for the Pantanal, Brazil

Herein we report the first record of Megalechis picta in the Brazilian Pantanal based in a single specimen captured in a tributary to the rio Miranda, municipality of Corumbá, rio Paraguay basin, State of Mato Grosso do Sul, Brazil. Additional discussion about its co-occurrence with M. thoracata is also provided.

Caracterização hidrogeológica e hidroquímica das águas subterrâneas da região de São Gabriel, RS

O presente estudo trata da caracterização hidrogeológica e hidroquímica das águas subterrâneas do município de São Gabriel, RS. Foram analisadas 55 amostras de água provenientes de 55 poços tubulares profundos de diversas localidades e variados contextos hidrogeológicos. A maior parte do território do município de São Gabriel é constituída por rochas sedimentares da Bacia do Paraná. Assim, os principais aquíferos possuem águas com composições químicas bastante diversificadas, refletindo variados ambientes deposicionais e composições mineralógicas. Subordinadamente, aquíferos fraturados formados por rochas granítico-gnáissicas do Escudo Sul- -rio-grandense ocorrem na porção sul do município. Desta forma, a qualidade das águas subterrâ- neas do município varia de acordo com as condições geológicas de cada unidade aquífera e com as relações entre elas. Na área, os elementos Flúor e Sódio são os parâmetros que comprometem a utilização das águas subterrâneas para fins de consumo humano, dessedentação de animais e irrigação. Cerca de 30 % das análises apresentam águas impróprias para consumo com relação a estes íons, conforme parâmetros máximos permitidos pelo Ministério da Saúde do Brasil. Os principais aquíferos da região, em termos quantitativos e qualitativos, são o Aquífero Rio Bonito (ARB) e o Sistema Aquífero Guarani (SAG), localizados, respectivamente, na porção sul e nordeste do município. As águas dos poços que captam destes aquíferos são de boa qualidade, potáveis e as vazões podem ser consideradas como as melhores da região .

Study of the West Gondwana Floras during the Late Paleozoic: A paleogeographic approach in the Paraná Basin – Brazil

Abstract The Late Paleozoic in West Gondwana was a period of significant climatic changes, ranging from a glacial climate in the Late Carboniferous to a semi-arid climate in the Late Permian. The Floristic Province of Gondwana in the Parana Basin was directly affected by such changes, and underwent a transformation regarding composition and geographic distribution. Thus, the climatic phases were divided into three intervals: Phase A containing interglacially developed flora; Phase B, containing floras of immediate post-glacial temperate climates, and phase C, identified with floras related to the decline of dryness. Regarding their geographical distribution, the floras were concentrated in the far-northern and far-southern portions of the basin during the Glacial interval, and, with a gradual increase in temperature, went on to occupy the entire basin. Finally, we can see that the floras located in the Argentinean portion of West Gondwana are older and have greater species diversity than those present in the Parana Basin and Africa during Phase A. In Phase B, there is a decline of Argentinean flora species, a large increase in the Parana Basin floras, and an average increase in African floras. In the final stage, the floristic province no longer exists in Argentina, the flora of the Parana Basin also suffers a decrease of specimens, and the African flora undergoes its moment of greatest development. Such diversity change also reflects a west-to-east migration throughout the Late Carboniferous.

Thermal Diffusivity of Sandstone Using Photoacoustics

An open photoacoustic cell was used to investigate the thermal diffusivity of sandstone taken from the Parana Basin, in Brazil. Although the organic-rich sedimentary rocks represent an important energy source in the Parana Basin, only limited data are reported concerning their thermophysical properties. A sandstone rock sample, from the Botucatu Formation, was investigated. The thermal diffusivity values were determined with uncertainties around 12 %, comparable to other methods. These values consider not only the experimental errors but also take into account the heterogeneity of the materials. It was possible to verify the behavior of the thermal diffusivity of the sandstone under heat treatment. The variation of the thermal diffusivity followed an expected trend, based on the possible variation of porosity which is related to the decomposition of some constituents. The results presented in this work identify the photoacoustic technique as a useful tool for thermal characterization of sedimentary rocks.

Possible polychaete tube worms from the Late Emsian (Early Devonian) of the Parana Basin, Brazil

Plastically deformed and silicified worm tubes from the Late Emsian (Early Devonian) of the Parana Basin are described herein as a new species and genus of annelid worms Annulitubus mutveii gen. et sp. nov. The tubes are straight and ornamented by smooth rings. Their microstructure is homogenous, which most likely is a diagenetic alteration. The characteristic early diagenetic compression of the tubes may point out to their original elastic organic tube wall. We cannot state it with full confidence but the most likely tube producers were tube-dwelling polychaete annelids, which were otherwise uncommon in the Paleozoic times.

Interpretação qualiná, sul do Brasiltativa e semiquantitativa dos dados aeromagnéticos sobre a zona de cisalhamento lancinha, porção meridional do cinturão ribeira no estado do Para

The characterization of shear zones at the southern portion of the Ribeira Belt, PR, BR, as well as its recognition in depth is a major challenge. Despite the lack of subsurface information, the influence of such structures on the installation and evolution of the Parana Basin during the Phanerozoic is widely accepted. Therefore, in this paper, are applied methods of anomaly enhancement (qualitative analysis) and estimative of the sources depth (semiquantitative analysis), on the aeromagnetic coverage of the Lancinha Shear Zone area (LSZ) in the Parana state, in order to verify its spatial arrangement in subsurface. The processing resulted in the interpretation of magnetic-structural framework of the study area, which was validated by the depth estimative of the magnetic sources (Euler solutions). The results indicated the extension of the Lancinha, Morro Agudo and Itapirapua shear zones under the Parana Basin coverage.

Lowstand Turbidites and Delta Systems of the Itararé Group in the Vidal Ramos region (SC), southern Brazil

Turbidites have captioned the attention of sedimentologists during the last decades due their importance as hydrocarbon reservoirs. However, their relationship to delta systems still deserves further studies. This paper presents examples from a late deglacial to early post-glacial deltaic and turbidite strata exposed in the surroundings of Vidal Ramos (Santa Catarina State, Brazil), southern portion of the Parana Basin. There, the uppermost part of the Mafra Formation and the Rio do Sul Formation onlap the Proterozoic basement and comprises an up to 360 m thick package. It includes (base to top) black shales, mass transport deposits (MTD) and sandy turbidites (Mafra Formation) as well as thin bedded turbidites (tbt), including one interval of black shales and sandy turbidites, overlain by proximal delta front sandstones (Rio do Sul Formation). The analysis of the succession shows two more than 150 m thick coarsening-upwards deltaic successions composed of turbidite sand sheets at their base (prodelta), followed by partially collapsed thin bedded turbidites (delta slope wedge) and delta front sandstones. Both turbidite sand-sheets abruptly overlay black shale intervals related to maximum flooding surfaces and therefore record correlative conformities. A detailed stratigraphic section elaborated from the correlation of four logs (1/100) suggests that distal delta front sands includes both thin bedded turbidites and wave reworked sands whereas the proximal delta front was dominated by long-lived underflows (hyperpycnal flows). The succession suggests that the most expressive turbidite beds (base of the delta systems) have resulted from relative sea-level falls (early lowstand) whereas the thin-bedded turbidites were related to the development of the late lowstand wedge. Black shales represent the transgressive systems tract and HST were not deposited or preserved in the area. High sediment supply associated with lowstand tracts could explain the occasional (Vidal Ramos) to common occurrence of slope failures (slumps and diamictites) involving thin bedded turbidites and delta front sandstones. This situation is quite logical in terms of deglacial periods, and resulting high sediment supply, within a long-term icehouse context, with prevalence of lowstand to transgressive settings.

New approach for the study of paleofloras using geographical information systems applied to Glossopteris Flora

This paper introduces a methodology which makes possible the visualization of the spatial distribution of plant fossils and applies it to the occurrences of the Gondwana Floristic Province present on the eastern border of the Brazilian portion of the Parana Basin during the Neopaleozoic. This province was chosen due to the existence of a large number of publications referring to their occurrence, so that a meta-analysis of their distribution could be based on ample information. The first step was the construction of a composite database including geographical location, geology, and the botanical systematics of each relevant fossil. The geographical locations were then georeferenced for translation into various maps showing various aspects of the distribution of the fossils. The spatial distribution of the fossil-housing outcrops shows that these are distributed along the area of deposition studied. Although some genera persisted for long periods of time, others lasted for only short intervals. As time passed, the fossil composition underwent a gradual change from the Late Carboniferous (Itarare Group) to the Late Permian (Rio do Rasto Formation), with the number of genera represented decreasing from 45 in the Itarare Group to 11 in the Rio do Rasto Formation.

O potencial de geração CBM (Coalbed Methane) na jazida Sul Catarinense: 1. Características petrográficas e químicas das camadas de carvão da Formação Rio Bonito, Permiano da Bacia do Paraná

Atualmente, o CBM representa uma importante fonte de energia alternativa. A mais importante sucessão sedimentar portadora de carvão no Brasil ocorre na Bacia do Paraná, com as maiores reservas localizadas nas jazidas do RS e de SC. Este trabalho tem por objetivo analisar as características químicas e petrográficas das camadas de carvão de três poços, realizados recentemente na jazida Sul Catarinense (SC) nos municípios de Treviso e Araranguá, com o intuito de avaliar a capacidade de geração de gás metano associado. Foram coletadas amostras de sete camadas de carvão (Barro Branco, Irapuá, A, Bonito Superior, Bonito Inferior, Pré-Bonito Superior e Pré-Bonito Inferior) da Formação Rio Bonito que foram submetidas à análise petrográfica e química. O litotipo carvão fosco bandado (BD) predominou no CBM-SC-2012, e carvão fosco (D), no CBM-SC-2013. Os resultados petrográficos indicaram valores de 0,60 a 1,26 Rrandom (%), classificando o carvão segundo o rank desde betuminoso alto volátil C até betuminoso médio volátil. A análise de macerais mostra variação na composição das camadas, com predomínio de vitrinita e inertinita. Quanto à análise imediata, as amostras variaram de 34,93 a 65,70% em peso de cinza. O poder calorífico varia de 1858,0 a 5074,8 cal/g. O conteúdo de carbono varia de 4,15 a 65,81%, e o enxofre, de 0,22 a 12,43%. De acordo com os parâmetros analisados, as camadas Barro Branco e Irapuá apresentam as condições necessárias para geração e armazenagem de gás natural, enquanto a camada Bonito apresenta baixo potencial devido ao alto conteúdo de matéria mineral.

Homogenization dynamics of the fish assemblages in Neotropical reservoirs: comparing the roles of introduced species and their vectors

Non-native species introduced into reservoirs cause major changes in biodiversity, resulting in spatial and temporal biotic homogenization and/or differentiation. We used a sampling standardized temporally and spatially in reservoirs of basins located in the Neotropics, the Coastal, Iguacu, and Upper Parana basins. Our analyses were conducted at the interbasin and intrabasin scales, aimed at: (i) identifying the non-native species and their major vectors of introductions, (ii) assessing temporal and spatial changes in the fish assemblages, and (iii) evaluating temporal changes in the beta diversity of the basins/reservoirs. The spatial occupation of non-native species was variable, with Tilapia rendalli, Cyprinus carpio and Oreochromis niloticus the most frequently introduced species. This highlights aquaculture as the main vector of invasives on a large spatial scale. The percentage of non-native species at the interbasin and intrabasin scales increased over time. Temporal comparisons of the fishes support the hypothesis that biotic homogenization occurred at the interbasin scale, whereas the biotic differentiation was observed at the intrabasin scale. Beta diversity decreased over time at the interbasin and intrabasin scales, with decrease in species richness serving as the variable that best explained changes in biological diversity. There was no relation between beta diversity and time for the Iguacu.

Aeromagnetic data analysis and physical-chemical properties of some complexes from Goiás Alkaline Province

The Goias Alkaline Province (GAP), located on the north edge of the Parana Basin, has alkaline complexes with strong gravity and magnetic signatures. The 3D inversion of magnetic signal was performed on the aeromagnetic data. Since the intrusions present a strong remnant magnetizations as measured in the laboratory a careful analysis of this component was also realized. The sum vector of the remnant and induced components were used as a virtual induced magnetic field during the inversion process. The geometric parameters were obtained form the quantitative analysis of magnetic data using Total Gradient Direction and Analytical Signal Phase performed over magnetic signal reduced to the pole. Magnetic susceptibility and density were measured in laboratory. All those information were used as the initial model in the inversion. The results of 3D inversion show that the alkaline intrusions have roots up to 10-12 km depth. The magnetic susceptibility is distributed in almost spherical and cylindrical shapes. The possibility of spherical shapes arise the hypothesis that the GAP intrusions at the north part of the province represent magmatic chambers. The alkaline magma ascends from the lithosphere, used two main fault systems as space for emplacement. These faults systems appear in the magnetic signal analysis as linear magnetic features. Chemical analysis confirmed the alkaline and subalkaline character of the magmas. The high MgO content shows the primitive character of these intrusions but the Ba anomaly indicates a possible crustal contamination.

Distinção dos elementos deposicionais fluviais, eólicos e lacustres do Membro Morro Pelado, Permiano Superior da Bacia do Paraná

The Late Permian Morro Pelado Member is the upper part of the Rio do Rasto Formation of Parana Basin and is composed of an association of fluvial, eolian and lacustrine deposits. In order to depict its facies associations and depositional elements as well as to characterize the fluvial style, a facies and architectural element analysis was carried out in the eastern outcrop belt in Santa Catarina and Parana States, southern Brazil. Four facies associations (FA) were recognized: FA-A is interpreted as mixed-load meandering fluvial systems, with conspicuous laterally accreted macroforms, levees and floodplain fines; FA-B was deposited as terminal splays in the distal parts of the fluvial system, where sheet floods prevailed; FA-C defines a fluvial-dominated lacustrine delta formed in response to episodes of extreme flooding and rising water table in the terminal splay zone; FA-D comprises eolian dunes, wet and damp interdunes and eolian sand sheets that occur interbedded with the fluvial and lacustrine deposits marking periods of aridization in the alluvial plain. The vertical stacking pattern shows an upward increase in frequency and thickness of eolian deposits recording progressive expansion of the erg systems towards basin margins in response to progressive drying combined with high rates of accommodation and sediment supply.