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Ice age mass-transport deposits (MTD) occur in multiple stratigraphic intervals within the Permocarboniferous Itararé Group, in the Paraná Basin, and are exposed in several disconnected quarries and road cuts around the region of Mafra, southern Brazil. The most typical deposits are diamictites with muddy matrix, but silty-sandy diamictites and metric intercalations of deformed layers of sandstones and siltstones occur subordinately. Similar MTD facies have been described from better exposed and time equivalent successions in western Argentina. There, because of the km-scale exposures, MTDs can be mapped in their plenitude, giving better insights about their emplacement. In this paper, we describe the Brazilian MTDs and infer their modes of transport and deposition supported by comparisons with published Argentinean examples. Based on matrix constitution, presence of coherent blocks and rafts, and sedimentation phases, at least four types of MTDs can be identified: 1) Mud-rich MTD and isolated sandstone blocks; 2) Resedimented MTD represented by diamictites with folded blocks of diamictite, possibly corresponding to two phases of remobilization; 3) Sand/silt-rich MTD (evolved stage), and formed by deformed bands of sandstones and siltstones (mature stage); and 4) MTD with rafts of heteroliths and sandstone blocks. Usually MTDs rest on and scour into a fine-grained substrate such as thin-bedded turbidites and shale. The regional geological setting at Mafra points to an open embayment. The collapse of inclined depositional slopes related to high sediment supply associated with deglaciation was the major control on MTD development. However, the inferred proximity of the ice margin during slope failure was variable, suggesting MTD formation during different stages of a glacial cycle. • MTDs occur in different stratigraphic positions in Itararé Group during the LPIA. • The constitution of the MTD depends on the protolith and stage of evolution. • Comparing Paganzo with Mafra added knowledge about LPIA Mass Transport Deposits. [ABSTRACT FROM AUTHOR]

Apart from Vaca Muerta's case history in Argentina, the unconventional exploration in South America is still underdeveloped, and one of the causes is the scarcity of geological studies. The present paper enlightens the embryonic unconventional exploration in the Sergipe-Alagoas Basin by introducing a seismic interpretation workflow to map thin shale layers and the natural fracture system, a challenge in unconventional reservoir explorations. Fracture and faults are critical elements in exploring ultra-low permeability shale oil/gas reservoirs. Identifying and locating these structures influence modeling fluid flow, hydraulics, and simulation models to improve horizontal well-drilling plans. The workflow comprises four main steps: data pre-conditioning, well-to-seismic tie, seismic spectral blueing (for frequency enhancement), and, finally, spectral decomposition and advanced fault attributes. The proposed workflow was applied to a seismic dataset from the onshore Brejo Grande oilfield focusing on the source rocks of the Coqueiro Seco Formation, the main unconventional reservoir candidate in the basin. That approach allowed mapping the lateral continuity, truncation, faults, and fractures in these thin shale layers previously below seismic resolution. The mapped structures belong to the complex natural fracture system with faults distributed to all trend directions. These faults are distributed along two zones with distinct fault densities with a possible sweet spot outline. • We present an interpretation workflow implemented to unconventional reservoirs. • The workflow combines seismic-resolution enhancing techniques and fault attributes. • As a result, thin-shale layers and fault zones were identified at Coqueiro Seco Fm. [ABSTRACT FROM AUTHOR]

Abstract: The South American Guaraní Aquifer System covers the entire Parana basin and part of the Chaco-Parana basin. This system is one of the most important groundwater reservoirs; it is shared by four neighboring countries covering an area larger than one million square kilometers. The geological units closely related to the Guaraní Aquifer are the Piramboia and Botucatu Formations that consist of Triassic–Jurassic aeolian, fluvial and lacustrine sandstones, and the Serra Geral basalts with clastic intercalations. Serra Geral, an effusive Cretaceous complex, covers the sandstones and provides a high degree of confinement to the system. This paper presents the interpretation of magnetotelluric (MT) data collected during 2007–2008 in Entre Ríos Province, Argentina. These data, recorded in three profiles, mainly provide the depth to the crystalline basement, determinant for the presence of aquifer-related sediments. Models showed that the discrimination of the basalts strongly depends on local electrical characteristics. Model information is quite consistent with the information from oil and thermal wells located close to the profiles. [Copyright &y& Elsevier]

In the late Pleistocene, Panochthus was the most diverse genus of glyptodontids with five species: P. jaguaribensis , endemic to the intertropical region of Brazil, P. hipsilis from Bolivia, P. greslebini from Brazil and Argentina, P. tuberculatus from Uruguay and Argentina and P. frenzelianus, probably from the Pampean region, Argentina. In this paper we describe the robust caudal tube of a new species, Panochthus florensis n. sp., that inhabited the center of the Pampean region of Argentina at the end of the Pleistocene. The reduction in the number of central figures, a single apical figure, the absence of an apexian figure, and the lack of figures between the first pair of dorsal figures allow a rapid differentiation from the already known species. The striking diversity of Panochthus contrasting with that of other late Pleistocene glyptodontids, lead us to propose hypotheses for explaining this fact. • A new species of Panochthus from Argentina shows a distinctive caudal tube. • Panochthus diversity far exceeds Glyptodon and Doedicurus diversity during the late Pleistocene. Molecular and embryological reasons could explain a greater diversity of Panochthus compared to other glyptodontids. [ABSTRACT FROM AUTHOR]