Tafonomia de tempestitos conchíferos amalgamados da formação Teresina em Rio Preto (Estado do Paraná, permiano médio, bacia do Paraná) e suas implicações paleoambientais

The deposits of the Permian Teresina Formation are mainly characterized by fi ne-grained siliciclastic rocks and centimetric intercalations of tempestites (bioclastic sandstones and coquinas). Despite the relevance of the bivalve-rich carbonate beds of the Teresina Formation to paleoenvironmental studies, their taphonomy is still poorly studied. The fossil concentration studied in this work was found in a quarry in the city of Irati, Rio Preto district, Parana State. The fossil concentration is located in the middle/upper portion of the unit, far from the top. The studied bed is a bioclastic, intraclastic, peloidal, grainstone/ packstone, with abundant bivalve shell fragments, pelitic and micritic intraclasts, peloids, rare ooids and oncoids, as well as permineralized of Lycophyta microphylles and fish scales. The grains of this carbonate concentration show: high degree of time-averaging, variable degree of packing (dense to disperse), no sorting and chaotic orientation. Notably, the concentration includes a mixture of elements which are indicative of: a) restrictive, low energy, carbonate environment (peloids, ooids and oncoids); b) subaerial environment surrounding the main body of water (Lycophyta microphylles) and c) quiet-water environment punctuated by storm events, where the suspension-feeding bivalves thrived. At least four depositional events caused by storm fl ows were recorded. The amalgamated nature of the bed is a result of storm events in an intracratonic basin with very low seafl oor slope and low rates of sedimentation and subsidence.

Tafonomia de biválvios em calcários oolíticos da formação Teresina (Bacia do Paraná, Permiano Médio, Prudentópolis, PR)

Herein, it is presented the first detailed taphonomic study on bivalve mollusk shells preserved in the oolitic limestones of the Teresina Formation (probably Kungurian-Roadian, Lower-Middle Permian) in the eastern margin of the Parana basin. The selected beds are located in two quarries (informally named PRU 1 and PRU 2) in Prudentopolis municipality (Center-South Parana State), and positioned approximately in the middle of the formation and probably in the Pinzonella illusa Zone. The PRU 1 limestone ([approximately]30 cm thick), which is partially silicified and intercalated with predominantly pelitic rocks, is classified as a bivalve oolitic grainstone. The basal contact is erosive and the top shows symmetrical ripple marks, which are draped by shale with mud cracks. There are two fining-upwards successions characterized by dense to dispersed packing of the shells, which are usually disarticulated, randomly oriented (many nested/stacked) and mixed with some Formapelitic intraclasts. Microhummocky cross-stratification occurs a little below the top of the bed. The PRU2 bed is classified as ooidbivalve rudstone[approximately] (~5 cm thick), where all shells are disarticulated and fragmented, showing dense packing. The bivalves probably inhabited a muddy substrate and were mixed (as parautochtonous and allochthonous bioclasts) with ooids during high-energy storm events, including posterior shell displacement as a result of bioturbation. Thus, the calcareous beds represent amalgamated proximal tempestites with a complex taphonomic history, strong temporal/spatial mixing of bioclasts and limited paleoecological resolution. They are a typical example of shell beds generated in a huge epeiric sea, which was not necessarily connected to the ocean and where very low depositional-slope gradient, very slow subsidence and minimum sediment accommodation space caused frequent sediment reworking by storm related processes.

Camadas de tempestito grosso (coarse grained storm beds): exemplos do Permiano da bacia do Paraná

Tempestitos grossos constituem camadas delgadas de conglomerado gradando a arenito, com estratificação cruzada seguida de laminação ondulada truncante a simétrica e de drape/flaser de siltito/folhelho. Cinco exemplos extraídos do Permiano da bacia do Paraná ilustram esse tipo de depósito: três deles são de rochas siliciclásticas, contendo bioclastos de bivalves e vertebrados (Formação Rio Bonito-Membro Triunfo e Formação Palermo), enquanto os outros dois são de rochas carbonática e fosfática (respectivamente, formações Teresina e Corumbataí do Grupo Passa Dois). O componente tracional da base do tempestito grosso apresenta-se como arenite quartzoso/lítico ou grainstone oolítico com cimento calcífero preenchendo poros (casos das formações Palermo e Teresina). em sua maioria, os tempestitos grossos constituem pavimentos transgressivos intercalados em folhelhos ou tempestitos finos (arenitos muito finos a folhelhos com estratificação ondulada truncante-hummocky). em outro caso, extraído de subsuperfície, o pavimento transgressivo ocorre na base de uma sucessão progradante de barra de plataforma. O tempestito grosso da Formação Teresina constitui um evento transgressivo sobreposto a depósitos de barra de plataforma.

Conchostráceos com linhas de crescimento recurvadas junto à margem dorsal (famílias Palaeolimnadiopseidae e Perilimnadiidae) da formação rio do rasto, Permiano superior, bacia do Paraná, Brasil

Some Upper Permian conchostracans from the Rio do Rasto Formation (Parana Basin, South Brazil) have very characteristic recurved growth lines at the dorsal margin. All previously described specimens were classified as Palaeolimnadiopsis subalata (Reed) Raymond. However, a re-analysis of these fossils and of additional recently- collected specimens demonstrated that not all can be included in a single species, nor only in the Family Palaeolimnadiopseidae. According to their shape and the size of the umbo, they are classified into three species. The sub-elliptic carapaces with small anterior umbo are maintained in Palaeolimnadiopsis subalata (Reed, 1929) Raymond, 1946. The sub-circular carapaces with small sub-central umbo correspond to the new species Palaeolimnadiopsis riorastensis. The small size of the umbo is a character of the Family Palaeolimnadiopseidae. The small elliptic valves with large anterior umbo are assigned to the new species Falsisca brasiliensis of the Family Perilimnadiidae, which is characterized by large umbos. Palaeolimnadiopsis has a wide chronostratigraphic distribution, but Falsisca is restricted to the Upper Permian-Lower Triassic of Europe and Asia. This interval is in agreement with the probable Late Permian age of the respective strata of the Rio do Rasto formation. Falsisca was not previously recorded in Gondwana.

Seqüência Ordovício-Siluriana e Devoniana no Flanco Norte da Bacia do Paraná

Two stratigraphic sequences characterize the basal units of the Paraná basin. The Ordovician-Silurian sequence overlie directly the Neoproterozoic basement and consists of a 55m-thick unit of coarse-grained sandstones, diamictites, fossiliferous shales and fine-grained micaceous sandstones. The Alto Garças Formation constitutes the base of the sequence and is made of coarse-grained, massive and reddish sandstones associated with conglomeratic lenses. Diamictites with pebbles of diverse composition in siltic and arenaceous matrix were deposited during the Ordovician-Silurian glaciation. Whenever the basal sandstones are absent, the diamictites directly overlie the basement. The diamictites were previously included in the Vila Maria Formation. However our study revealed that they are part of the Iapó Formation. A transgressive event following the glaciation is marked by the deposition of the Vila Maria Formation, which is characterized by fossiliferous (mollusks, brachiopods, cryptospores and microplankton) and laminated shales and siltstones, grading upward to fine-grained micaceous sandstones with hummocky cross stratification. Layers containing trace fossils (Anthrophycus) occur at the transition between the siltstones and the sandstones. The Devonian sequence is represented by 80-170 meters thick sandstones of the Furnas Formation (lower unit) and a sucession of sandstones, siltstones and shales of the Ponta Grossa Formation (upper unit). Unlike other areas of the Paraná Basin, the Ponta Grossa Formation is characterized by coarsening-upward succession beginning with fine sandstones and grading upward to coarse and very-coarse sandstone beds. Cretaceous modifying tectonics affected the Paleozoic sequences, which are cut by a series of faults, in some cases showing displacements greater than 500 meters.

Estratigrafia de seqüências das formações Taciba e Rio Bonito (Membro Triunfo) na região de Mafra/SC, leste da Bacia do Paraná

The Taciba and Rio Bonito (lower Triunfo Mbr) formations are divided into six depositional sequences based on cores, gamma-ray and electrical logs from shallow drillings from northern Santa Catarina State, Each sequence is formed by two systems tracts, a lower one, sandy (lowstand) and an upper one, shaly (highstand). The Taciba Formation has three sequences, S 0 to S 0 sequence S 0 has a thick turbidite sandstone at the base (Rio Segredo Member) that pinches out towards the eastern margin and even disappears in the Mafra outcrop area. Sequence S 1 varies from a thin fluvial-estuarine system to a thick turbidite sandstone of a channelized fan system; S 1 upper shaly system tract is marine in well PP-11, and it is glacially-influenced in well PP-10. Sequence S 2 is a thick sand-stone body of shallow marine origin, but restricted to one well (PP-11); its upper shaly tract is dominated by massive siltstones intercalated with thin, distal tempestites. The lower Triunfo Member (or Taciba-Triunfo transition) begins with the arrival of deltaic clastics of sequence S 3 lower tract, coarsening-up from medial- to proximal delta front sandstones. Sequence S 4 is quite similar to S 3, both showing sand-stone progradation from north to south, as opposed to the southwest-sourced transgressive diamictites. Sequence S 5 consists of fluvial deposits at well PP-12, and two transgressive cycles from wells PP-11 to PP-9, each one of them composed of fluvial-estuarine to marine systems. Well PP-10 is an exception, where the lower cycle presents deglaciation to marine deposits.

As rochas intrusivas da Formação Serra Geral na Porção leste da Bacia do Paraná no Estado de São Paulo: Aspectos petrográficos e geoquímicos - Resultados preliminares

The purpose of this paper is to present preliminary aspects of the petrography and chemistry of intrusive rocks (sills and dykes) from the eastern portion of the Parana Basin in the State of Säo Paulo. Data from 80 samples of the region show a subaphyric and subophitic nature and have plagioclase (25-50%), augite (3-39%), pigeonite (0-10%) and magnetite (4-20%) as an essential minerals. Apatite and quartz are present as accessory minerals. The geochemical data of intrusive rocks show a basic to intermediate composition (48% < SiO 2 < 56%) and a high Ti nature (TiO 2 > 2%). Based on the minor and trace composition of the intrusive rocks, two different magma types were recognized, named Paranapanema and Pitanga. The spatial distribution of these magma types is not alleatory in the studied region. The intrusive rocks of Pitanga magma type are displayed in the Campinas-Paulinia region, while the Paranapanema magma type cover a large region above that one, between Rio Claro and Cajuru. Furthermore, the chemical composition of the lava flows of the Serra Geral Formation, sampled in this work, reveals a magma of Urubici type. So, the intrusive rocks of the eastern portion of the of State Säo Paulo are not the extension of the lava flows, or they aren't a portions which don't reach the surface.

A seqüência mafra superior \ Rio Do Sul inferior (Grupo itararé, permocarbonífero) em sondagens testemunhadas da região de mafra (SC), Margem Leste da Bacia do Paraná

The Permo-Carboniferous Harare Group crops out in the Matra area, represented by Campo do Tenente, Mafra and Rio do Sul formations; they correspond in subsurface to Lagoa Azul, Campo Mourão and Tacïba formations. A composite sampling of the Group was performed through drilling of six wells, which average 60 m in depth; three of them cored the depositional sequence here designated as Upper Mafra\Lower Rio do Sul. The Upper Mafra Formation were sampled by TC-4 and BR-5 wells, and it consists of three units: the lower two are sandy, glacial-deltaic and fluvial-deltaic in origin, corresponding to a lowstand tract. The last unit is composed of two dirtying-upward successions of sandstone, diamictite and rhythmite, interpreted as deglaciation/transgressive events, and well represented in BR-5 drilling. The Lower-Rio do Sul Formation (Lontras Shale) is formed by two marine units: the lower one is represented by shale and bioturbated siltstone which culminate the previous deglaciation, transgressive succession, while the upper one, sampled by SL-2 well, is formed by shale and thin, turbidite sandstone, attributed to a highstand tract.

Significado paleobiológico de agrupamentos (coloniais/ gregários) de Conularia quichua Ulrich, 1890 (Cnidaria), Formação Ponta Grossa, Devoniano (Pragiano-Emsiano), Bacia do Paraná, Brasil

The Conularia beds of the Ponta Grossa Formation (Devonian) of the Paraná Basin, southern Brazil, yield well-preserved specimens of Conularia quichua Ulrich and Paraconularia africana Sharpe. Many of these are preserved in life orientation. Also, one of the C. quichua specimens has five faces instead of four, providing additional evidence of a cnidarian affinity for conulariids. Conulariids occur in the Jaguariaíva Member (or Sequence B, transgressive system tract) containing several obrution deposits beneath marine flooding surfaces. Taphonomic data obtained from these beds show conclusively that both C. quichua and P. africana were epibenthic, sessile invertebrates originally oriented with their long axis perpendicular to the bottom and with their aperture opening upward. Of the 136 C. quichua specimens examined here, 125 occur isolated. Eleven of the C. quichua specimens collectively occur in five discrete clusters consisting of two or three specimens. All of the clustered specimens are fully inflated (exhibiting a rectangular transverse cross section) or slightly compressed longitudinally. In all of these specimens the apex is missing, and thus the problem of whether the clusters were clonal colonies or formed through preferential larval settlement cannot be resolved conclusively. However, in the single cluster consisting of three specimens, the specimens are oriented perpendicular to bedding, and thus they do not converge adapically. The three specimens are in contact with each other along the upper portion of their median region. These and the lack of any evidence of a sheet of budding stolons, suggest that this cluster was formed by preferential larval settlement. © Asociación Paleontológica Argentina.

A tectônica meso-cenozóica de parte da borda nordeste da Bacia do Paraná: traços de fissão em apatita

The possible development of thermal events in the central portion of São Paulo state was described based on apatite fission track analysis. Using apatites of sedimentary rocks of the Paraná Basin, modeling the thermal history was made possible due to the homogeneity of the data. Every thermal history begins with a total annealing of fission tracks, related to the Serra Geral magmatism, evolving into a cooling period. In addition to cooling after the magmatism (Early Cretaceous) two other periods of cooling were also detected, registered in the Late Cretaceous/ Paleocene and Eocene, driven as much by uplift with tectonic denudation as by faulting. The nearest portion of the edge of the basin (external to the Dome of Pitanga), registered a period of warming over the Paleocene that can be attributed to the increase in the geothermal gradient. The periods of cooling have a regional and temporal relationship with the tectonic events that occurred in the southeastern Brazil and were described in the crystalline basement. The period of warming, registered in the Late Cretaceous/ Paleocene, has local occurrence and can be found only in the southern portion of the studied area.

Metacryphaeus rotundatus, um novo elemento da fauna de trilobites calmoniidae (phacopida), da formação Ponta Grossa (Devoniano), bacia do Paraná, Brasil

Calmoniids (Delo, 1935) are the most common and abundant group of trilobites of the fossil record of the Devonian Ponta Grossa Formation in the Apucarana sub-basin. Although known since the past century, the study of calmoniids has been taxonomically and stratigraphically biased. This is because some authors centered their studies on some particular genera from a few stratigraphic horizons within the basal portion of the Ponta Grossa Formation. The analyses of 398 specimens of calmoniid trilobites of the rocks of Jaguariaiva Member of the Ponta Grossa Formation, mainly from Tibagi county in the state of Paraná, Brazil, indicate the presence of specimens that are referable to Metacryphaeus rotundatus (Kozlowski, 1923). This is the first record of M. rotundatus in Brazilian Devonian rocks. Metacryphaeus rotundatus is a conspicuous species of the Emsian rocks of the Icla Formation, Bolivia. Although the affinities of the trilobite fauna of the Devonian Paraná Basin, in the context of the Malvinokaffric realm, are with the Brazilian and South Africa provinces, this finding is in accordance with new evidence (e.g., conulariids, homalonotids trilobites), indicating the presence of cosmopolitan species with Andean affinities. Metacryphaeus rotundatus lived in a broad paleoclimatic range, from a temperate, cold temperate to a subpolar climate. Finally, in the Devonian of the Paraná Basin, M. rotundatus lived and were preserved in muddy, organic rich bottoms, deposited in offshore waters, below the storm wave base, associated to marine flooding surfaces.

Conchostráceos com linhas de crescimento recurvadas junto à margem dorsal (Famílias Palaeolimnadiopseidae e Perilimnadiidae) da Formação Rio do Rasto, permiano superior, Bacia do Paraná, Brasil

Some Upper Permian conchostracans from the Rio do Rasto Formation (Paraná Basin, South Brazil) have very characteristic recurved growth lines at the dorsal margin. All previously described specimens were classified as Palaeolimnadiopsis subalata (Reed) Raymond. However, a re-analysis of these fossils and of additional recently- collected specimens demonstrated that not all can be included in a single species, nor only in the Family Palaeolimnadiopseidae. According to their shape and the size of the umbo, they are classified into three species. The sub-elliptic carapaces with small anterior umbo are maintained in Palaeolimnadiopsis subalata (Reed, 1929) Raymond, 1946. The sub-circular carapaces with small sub-central umbo correspond to the new species Palaeolimnadiopsis riorastensis. The small size of the umbo is a character of the Family Palaeolimnadiopseidae. The small elliptic valves with large anterior umbo are assigned to the new species Falsisca brasiliensis of the Family Perilimnadiidae, which is characterized by large umbos. Palaeolimnadiopsis has a wide chronostratigraphic distribution, but Falsisca is restricted to the Upper Permian-Lower Triassic of Europe and Asia. This interval is in agreement with the probable Late Permian age of the respective strata of the Rio do Rasto Formation. Falsisca was not previously recorded in Gondwana.

Diques clásticos na formação corumbataí (p) no nordeste da bacia do paraná, SP: Análise sistemática e significações estratigráficas, sedimentológicas e tectônicas

This paper aims to present the results of systematic survey on clastic dykes in the Corumbataí Formation (Permian), in the northeast region of the State of São Paulo. Besides this, the paper analyses genetic aspects of those features as well as their stratigraphic and sedimentologic implications in terms of geologic evolution of the northeastern Paraná Sedimentary Basin during Permian times. The field works had been developed in 3 main Corumbataí Formation outcrops (2 road cuts and a quarry) supposed to show the most important clastic dikes occurrences in the studied area. Basically, the sedimentary intrusions are formed by fine sand or silt size particles and had penetrated host rocks as near-vertical, centimeter thick, dykes (most common form) or as horizontal sheets, forming clastic sills (subsidiary form), both with variable geometric forms and dimensions. A lot of dyke walls show undulations suggesting pre-diagenetic clastic intrusions, probably near the ancient depositional surface. Almost all intrusions occur in the superior third portion of the Corumbataí Formation and some similar features seem to appear in the adjoining superposed Pirambóia Formation base. In this article the authors defend a seismic origin hypothesis for the clastic intrusions. It is important to mention that clastic intrusions tend to occur linked to expressive seismic events, with magnitude upper to 5. The analysis of isopach maps of the Permian and Mesozoic units of the Paraná Sedimentary Basin in the study area suggests a depositional system changing, from epicontinental sea conditions to shallow platform and, finally, to coastal deserts. Probably, this environmental change was driven by regional uplift accompanied by seismic events. It is possible that ancient seismicity triggered liquefaction processes and the resulting clastic intrusions. In this sense, those clastic features might be properly namedseismites.

Grupo itararé (P - C da bacia do Paraná) nas regiões de Limeira e Piracicaba - SP: Contribuição ao estudo das litofácies

The Permian-Carboniferous Itararé Group is one complexe lithostratigraphic unit of the Paraná Basin, southeastern Brazil, typically marked by discontinuity of its lithofacies. Under the exploratory point of view, the unit represents one of the most significant intervals of the basin, since several occurrences of mineral and energetic resources are associated to it, as groundwater, petroleum and coal. The prospection and exploitation of these resources depend on a good understanding of the stratigraphic architecture and the paleogeography. There are many contributions on the specialized literature which deal with this subject, although the regions of Limeira and Piracicaba (superior portion of the unit) still lack new investigations, which may contribute to the understanding of its lithofacies and related sedimentary processes. It was analyzed the sedimentary sets pilling up, followed by stratigraphic correlations between the two regions. Moreover, from sedimentary structures, it was made paleocurrent measurement with the purpose of obtaining indicative patterns of the sedimentary polarity, contributing for the comprehension of the paleogeography. Recent studies in the Domo de Pitanga region (between Rio Claro and Piracicaba cities) and in the Corumbataí river drainage basin, were taken also as basis for possible correlations. It was obtained a frame of the lithofacies arrangement, their vertical and lateral relations, as well as their depositional polarities.

Caules permineralizados de Tietea e Psaronius na Bacia do Paraná (Formação Corumbataí, Permiano)

PERMINERALIZED STEMS OF TIETEA AND PSARONIUS OF THE PARANÁ BASIN, CORUMBATAÍFORMATION, PERMIAN. Silica permineralized stem fragments from six municipalities of São Paulo, Brazil, belonging to the Passa Dois Group, Corumbataí Formation (Guadalupian, Permian), were analysed. Morpho-anatomic characteristics of the stems and steles, observed on petrographic slides or polished sections, have permitted the classification of many specimens as Tietea cf. Tietea singularis. A stem piece from the region of Casa Branca, determined as Psaronius cf. Psaronius arrojadoi, corresponds to the first true record of this genus in the Paraná Basin. A generic/specific identification was not possible for radicular mantle samples having no preserved steles. Despite the strong influence of taphonomic factors on the record, all known Marattiales fossils from the Paraná Basin in Brazil present relatively small steles and meristeles, and that may be related to hydric stress. Taphonomic, paleoecological and biogeographical aspects of the analysed fossils are discussed as well.