Parana Basin Research Articles

Formação Serra Geral (Cretáceo da Bacia do Paraná): um análogo para os reservatórios ígneo-básicos da margem continental brasileira

O estudo das rochas ígneas é de especial interesse nas bacias sedimentares produtoras de hidrocarbonetos pela possibilidade de constituírem reservatórios vulcânicos não convencionais. Na Bacia de Campos, situada na margem continental sudeste do Brasil, os campos de Badejo e Linguado produzem a partir de reservatórios vulcânicos fraturados que se constituem no seu embasamento econômico. São derrames de rochas básicas, vesiculares, fraturados e intercalados por intertraps arenosos. Estes campos produtores são offshore e o reservatório não convencional encontra-se a grandes profundidades, submerso, dificultando o entendimento tanto do modelo bem como do sistema permo-poroso responsável pela acumulação do hidrocarboneto. Assim, há necessidade de um modelo análogo em superfície que permita a visualização e o entendimento do reservatório e das feições permo-porosas. A Formação Serra Geral (vulcanismo do Cretáceo da Bacia do Paraná) é considerada como o modelo análogo para reservatórios vulcânicos fraturados. Com base no estudo de afloramentos de rochas vulcânicas dessa formação nas regiões do Salto do Jacuí e Torres, no estado do Rio Grande do Sul e no emprego de técnicas petrográficas, geoquímicas, de difratometria de raios X e de microscopia eletrônica de varredura é proposto um modelo análogo. No presente modelo, falhas, fraturas, vesículas e microfraturas constituem o sistema permo-poroso e permitem o entendimento de diversos reservatórios não convencionais em sub-superfície, especialmente os vulcânicos.

Two new species of the Hypostomus cochliodon group (Siluriformes: Loricariidae) from the rio Paraguay basin, with a redescription of Hypostomus cochliodonKner, 1854

Hypostomus cochliodon group is a monophyletic clade of 20 valid species of Neotropical armored catfishes that is widely distributed throughout South America. Recently, specimens identified as H. cochliodon from the type locality and nearby localities were examined, and found to include representatives of more than one species. A redescription of H. cochliodon is provided, with a description of two new species, one from the Bodoquena Plateau and another from several localities of the rio Paraguay basin. A lectotype for H. cochliodon is designated herein, since the previous designation is invalid. Hypostomus cochliodon is diagnosed from all other species of the H. cochliodon group by having the opercle almost completely covered laterally by thick layer of skin, the absence of buccal papilla, weak to moderately developed keels on the lateral plates of the body and by the color pattern of its body and fins. Hypostomus basilisko, new species, is distinguished from the remaining species of the H. cochliodon group by the absence of spots on the body, highly developed keels and spoon-shaped teeth. Hypostomus khimaera, new species, is distinguished from the other species of the H. cochliodon group by having a dark tan stripe along the midline of the flank, black spots on the body and/or fins and teeth with mesial cusp and not spoon-shaped.

Chromosomal polymorphism in Rineloricaria lanceolata Günther, 1868 (Loricariidae: Loricariinae) of the Paraguay basin (Mato Grosso do Sul, Brazil): evidence of fusions and their consequences in the population.

Rineloricaria is the most species-rich genus of the Loricariinae (armored catfish) with 65 valid species. However, the karyotype structure is known only for eight species in this group. This study provides cytogenetic data for Rineloricaria lanceolata collected from the upper Paraguay basin (Mato Grosso do Sul). The specimens revealed extensive chromosomal polymorphism constituting 10 karyotypes, which differed in the diploid number (48 to 45 chromosomes) and fundamental number (FN) between 52 and 55. Three types of chromosome variants were observed: a medium-sized submetacentric, a large submetacentric, and a small acrocentric form. Internal telomere sequences were demonstrated by a telomeric (TTAGGG)n probe in submetacentric chromosome variants, suggesting Robertsonian and tandem fusions. Considering the karyotype 2n=48 (4m+2st+42a, FN=54) as the starting point for this polymorphism, these rearrangements contributed to the reduction in diploid number (48-45). Furthermore, a remarkable polymorphism of 18S rDNA resulted in three nucleolus organizer region phenotypes (I, II, and III) with variable frequencies. Interestingly, this polymorphism has remained in the population through interbreeding between specimens, resulting in different viable combinations. The data obtained confirm that diversification/karyotype evolution in Rineloricaria was marked by numerous chromosomal rearrangements which appear to be well tolerated in the panmitic population.

Estratigrafia e estrutura do Cerro do Jarau: nova proposta

The Cerro do Jarau structure is located near the town of Quarai, in the Rio Grande do Sul state, close to the international boundary with Uruguay. This circular feature has a diameter with approximately 8 km, presents some evidence of an origin by a meteoritic impact. It is located in the Parana Basin and characterized by a central area with occurrence of sandstone surrounded by basalts of Serra Geral Formation. Previous works considered the structure as a dome-shaped feature. The objective of this paper is to present new data on the stratigraphy and structure of the Cerro Jarau, showing that the sandstones are structurally and stratigraphically overlying the basalts and both units exhibit centripetal dips. The structure of Cerro Jarau is therefore a basin-like feature and not a dome as admitted in previous studies.

Description of two new species of Hisonotus Eigenmann & Eigenmann, 1889 (Ostariophysi, Loricariidae) from the rio Paraná-Paraguay basin, Brazil

Two new species of Hisonotus are described from the rio Paraná-Paraguay basin in Brazil. The most remarkable features of the new species are the odontodes forming longitudinally aligned rows (one odontode after the other, but not necessarily forming parallel series) on the head and trunk (vs. odontodes not forming longitudinally aligned rows), a pair of rostral plates at the tip of the snout (vs. a single rostral plate), the functional v-shaped spinelet (vs. spinelet non-functional, square-shaped, or absent). These features suggest close phylogenetic relationships with Hisonotus bockmanni, H. insperatus, H. luteofrenatus and H. piracanjuba. Additionally, both new species are distinguished from their congeners by characters related to head length and depth, orbital diameter, suborbital depth, caudal peduncle depth, pectoral-fin spine length, snout length and counts of teeth. Hisonotus paresi sp. n. further differs from its congeners by having contrasting dark geometric spots on the anterodorsal region of the body, a character lacking in H. oliveirai sp. n. The variation in number and shape of the rostral plate, posterior rostrum plates, infraorbitals and the preopercle in both new species and in H. insperatus are discussed.

Mapeamento das águas subterrâneas do município de Boa Vista do Cadeado/RS

A poluição gerada pelas atividades antrópicas tem despertado a necessidade contínua de conhecer e avaliar as condições do meio ambiente em relação a possíveis fontes de contaminação, principalmente as prejudiciais aos recursos hídricos subterrâneos. Por meio deste estudo, referente ao Município de Boa Vista do Cadeado, no Estado do Rio Grande do Sul, situado na Mesorregião noroeste riograndense, inserido na Província Geomorfológica do Planalto Meridional Brasileiro, onde afloram derrames de rochas vulcânicas formadoras do Sistema Aquífero Serra Geral/SASG. Espacializaram-se mapas temáticos referentes aos dados hidrodinâmicos dos poços tubulares tais como: nível estático, vazão, superfície potenciométrica, capacidade específica e índices de vulnerabilidade natural do aquífero à contaminação. Utilizando-se o sistema GOD, simularam-se 12 captações por poços. Foram obtidas duas classes de vulnerabilidade natural, sendo 83,3% na classe insignificante e 16,7% na baixa. Conclui-se que a região apresenta-se pouco vulnerável à contaminação, possuindo uma proteção natural, devido às camadas de rochas vulcânicas basálticas, em aquífero confinado e com um nível médio da água, pouco profundo.

Conchostráceos como evidência de níveis jurássicos na Formação Caturrita, Faxinal do Soturno, Rio Grande do Sul, Brasil

This paper focus on the first conchostracans (Crustacea, Spinicaudata) found at the Sao Luis outcrop (Caturrita Formation, Rosario do Sul Group), in Faxinal do Soturno, Rio Grande do Sul State, Brazil (29o 33' 29.09S, 53o 26' 54W). Fossil vertebrates and plants identified at this outcrop suggest conflicting ages, respectively Late Triassic and Early Jurassic. Dinosaur tracks recently found at the upper part of the outcrop enhance these age problems. In this way, the conchostracans constitute important additional elements in this discussion. Some specimens share many characteristics with Carapacestheria disgregaris (Tasch) Shen (Eosestheriidae) of the Ferrar Group, Lower-Mid Jurassic of the Transantartic Mountains. But differences in the ornamentation details led to the proposal of a new genus and a new species, Nothocarapacestheria soturnensis, and to the interpretation of a close phylogenetic relationship with the Antarctic species. Other samples in this assemblage are similar to Australestheria corneti (Marliere) Chen (Fushunograptidae) of the Middle Jurassic from Zaire. Together, these conchostracans substantiate a Jurassic age and corroborate the data of the Bennettitales flora found at the same levels in the outcrop. However, the Late Triassic age indicated by the tetrapods cannot be discarded according to their lower stratigraphic position in Sao Luis outcrop. In the same way, the present chronostratigraphic discussion does not apply to the other occurrences of the Caturrita Formation, especially because the correlations between outcrops are extremely difficult, both by the lack of paleontological support and by the numerous faultings during the Mesozoic sedimentation in the southern part of the Parana Basin.

Correlation of lineaments (magnetic and topographic) and Phanerozoic brittle structures with Precambrian shear zones from the basement of the Paraná Basin, Santa Catarina State, Brazil

The objective of this article is to characterize the main directions of structures of the Parana Basin, to define the relation of deep structures (magnetic lineaments) with superficial structures [lineaments obtained over Shuttle Radar Topography Mission (SRTM) images] and analyse reactivated structures in the Phanerozoic. The magnetic lineaments at the Eastern edge of the Parana Basin, in the central-southern region of the Santa Catarina State, show a main orientation pattern NE-SW and secondarily NNE-SSW. The NE-SW pattern reflects a framework of the ductile structures of the Santa Catarina Shield that continues in the substratum of the basin. The structural NNE pattern appears in the south of the Major Gercino Shear Zone (MGSZ) and the NE pattern appears in the north of this structure. The data obtained shows that the structural NE-SW pattern of the basin, present in the MGSZ and Itajai-Perimbo Shear Zone as well as in the Tijucas Terrain (Brusque Metamorphic Complex) in Santa Catarina, clearly extends underneath the Gondwanic sequence of the Parana Basin in the region. Among the products obtained by geophysical data processing in this work, what propitiated the best definition and distinction of the magnetic structures was the tilt angle of the total horizontal gradient (TAHG) method. However, the great flight line spacing of one of the geophysical projects (7 km) makes the identification of small magnetic structures difficult, particularly in N-S and E-W directions. Such structural directions are referred to in the previous works and were confirmed through the interpretation of SRTM images and studies of brittle structures in the field.

Concentrações de metais em solo ocupado por cemitério - uso da técnica de espectrometria de fluorescência de raios-x por energia dispersiva - EDXRF

O estudo de contaminação de solos e dos recursos hídricos superficiais e/ou subterrâneos por cemitérios é uma área ainda recente no meio científico. O principal contaminante é o necrochorume gerado a partir do processo de decomposição dos corpos humanos, ao longo de um período de tempo. Este estudo teve como objetivo, determinar a faixa de variação da concentração de alguns metais em perfis de solos. Utilizou-se a técnica de Fluorescência de Espectrometria de Energia Dispersiva de Raios X (EDXRF), avaliados em 70 amostras de solos. A área estudada foi um cemitério, localizado na cidade de Seberi, no noroeste do Estado do Rio Grande do Sul, na Bacia do Paraná, em Latossolos vermelho alumino férrico, originados do intemperismo de rochas vulcânicas, do tipo basaltos formadoras do Sistema Aquífero Serra Geral/SASG. A seleção dos pontos de amostragem foi estimada a partir do fluxo preferencial de água de superfície, usando-se o método matemático de interpolação krigagem. Foram considerados 10 pontos de coletas, distribuídos entre a superfície do terreno até a profundidade de 300 cm, em materiais com matriz argilosa até pedregosa no horizonte C. Os metais Alumínio e Ferro e o metalóide Vanádio, apresentaram concentrações variadas nas diversas profundidades do perfil do solo.

Ice-Keel Scour Marks In the Geological Record: Evidence From Carboniferous Soft-Sediment Striated Surfaces In the Parana Basin, Southern Brazil

Abstract Soft-sediment glacially striated surfaces are common structures in ancient glacial successions, such as the Gondwanic Paleozoic record, and document ice erosion on non lithified beds. In most cases, they have been interpreted as the product of subglacial erosion beneath advancing marine or terrestrial glaciers, although direct evidence for glacial sedimentation in associated strata is infrequent. In this paper we document soft-sediment striated surfaces of Carboniferous age occurring in cross-laminated sandstones of the lower Itarare Group, southern Parana Basin, Brazil, and interpret them as scour marks generated by keels of floating ice. Striated surfaces occur in closely spaced, multiple stratigraphic horizons in the lower half of a deglacial sequence, whose facies characteristics indicate sedimentation in subaqueous outwash and deltaic settings. Surfaces are laterally discontinuous, commonly bordered by marginal berms, and in some cases capped by mudstones with dropstones; they have orientations that deviate from the regional paleo-ice flow indicated by glacial grooves carved on the pre-glacial basement. The characteristics observed are consistent with modern and Pleistocene ice-keel scour marks. In addition, soft-sediment striated surfaces from other Gondwanic localities have similar attributes, suggesting that ice-keel scour marks may be more common in the geological record than previously considered and that vertically repeated striated surfaces do not necessarily indicate multiple ice-sheet advances. Therefore, paleo-ice flow reconstructions based on soft-sediment striated surfaces need to be revaluated considering that the movement of free-floating ice masses is controlled by phenomena other than glacier advance.

Extreme Rainfall Indices in the Hydrographic Basins of Brazil

The authors analyze climate extremes indices (CEI) of rainfall over the largest basins of the Brazilian territory: Amazon (AMA), S?o Francisco (SF), Tocantins (TO) and Parana (PAR) rivers. The CEI represent the frequency of heavy precipitation events (R30mm and R95p) and short duration extreme rainfall (RX5day and RX1day). Droughts (CDDd) are identified based on two indicators: The longest dry period (CDD) and the annual cycle. The results demonstrate that CDDd, RX1day and RX5day occurred with more frequency and intensity in SF basin during El Ni?o events. CDDd was of greater magnitude in the TO basin during La Ni?a events, while an increase of RX1day occurred in El Ni?o. The strong El Ni?o events (1983 and 1997) caused more intense and frequent RX1day and R30mm over the PAR basin. Amazon droughts occurred in two out of the six El Ni?o events. Moreover, the relationship between the positive (negative) sea superficial temperatures anomalies in North (South) Tropical Atlantic and drought in AMA basin was corroborated. A gradual warming of SST was observed at the start of 2003 until it achieved a maximum in 2005 associated with the southwestern Amazon drought. The second highest anomaly of SST was in 2010 linked with drought that was more spatially extensive than the 2005 drought. The spatial distribution of annual trends showed a significant increase of CDD in south-eastern AMA, Upper SF, northern PAR and throughout the TO basins. R20mm, RX1day and RX5day tend to increase significantly in southwestern (northeast) PAR (AMA) and northwestern TO basins. Comparisons between CEI derived from daily precipitation data from Climate Prediction Center (CPCp) and of the ETA_HadCM3 model showed that the model overestimated RX1day, RX5day and CDD, in the four basins. Future scenarios show that dry periods will occur with greatest magnitude in all the basins until 2071-2099 time slice, while RX1day will be more intense in the TO and SF basins.

PENTACYCLIC TERPANES AS INDICATORS OF COMPOSITIONAL HETEROGENEITIES IN BIODEGRADED OIL RESERVOIR

Reservoir geochemistry has been effectively used to evaluate compositional heterogeneity in petroleum reservoirs by employing oil fingerprinting technique to assess reservoir continuity, primarily in paraffin oil accumulations. In-reservoir biodegradation has resulted in vast deposits of heavy oils globally; therefore, the application of reservoir geochemistry to such accumulations becomes necessary. We recommend the use of pentacyclic terpanes instead of lower molecular compounds, which are less resistant to biodegradation. Using oil fingerprinting technique in this novel way enabled the differentiation of oil composition among sedimentary facies of tar sands (Piramboia Formation, Parana Basin).

On a new Stereospondylomorpha temnospondyl from the Middle/Late Permian of Southern Brazil

A new temnospondyl is described from the Middle—Upper Permian sequence of the Parana Basin (Rio do Rasto Formation) in southern Brazil. The material consists of disarticulated cranial and postcranial elements, preserved in association. The cranial elements include part of the orbital region of the skull roof, the basicranium, a number of endocranial elements, stapes and a right hemimandible. The postcranial elements include vertebrae, ribs, pectoral girdle elements, a right femur and a cluster of scales. The new species displays a rhinesuchid pattern, which is similar to the South African rhinesuchids from the Upper Permian Beaufort Group of the Karoo Basin, but differs from them by the presence of a robust and elongated epipterygoid with a blade-like anterior process in addition to elongated and deeper muscular pockets on the parasphenoid, which allow the assignment of this specimen to a new species. However, the phylogenetic analysis grouped the material described herein and Australerpeton cosgriffi ins...

<p><strong><em>Loricaria luciae</em>, a new species of whiptail catfish (Siluriformes: Loricariidae) from the Paraguay and lower Paraná River basins of southeastern South America</strong></p>

Loricaria luciae, new species, is described from the the rio Paraguay basin of Bolivia, Brazil, and Paraguay, south to its confluence with the rio Paraná in Argentina. It is distinguished from all congeners by the following combination of characteristics: pectoral girdle entirely naked or with small isolated plates near base of pectoral fin, post-ural plate at base of caudal fin large (plate length 17.0–20.3% HL), and total lateral plates 32–33 (modally 32). The new species occurs in a variety of habitats ranging from small, seasonally intermittent streams with clear water to large, turbid rivers over sand and mud substrates. It is sympatric with at least three other species of Loricaria in the Paraguay and lower Paraná drainages, including L. apeltogaster Boulenger 1895, L. coximensis Rodriguez et al. 2012, and L. simillima Regan 1904.

Loricaria luciae, a new species of whiptail catfish (Siluriformes: Loricariidae) from the Paraguay and lower Paraná River basins of southeastern South America.

Loricaria luciae, new species, is described from the the rio Paraguay basin of Bolivia, Brazil, and Paraguay, south to its confluence with the rio Paraná in Argentina. It is distinguished from all congeners by the following combination of characteristics: pectoral girdle entirely naked or with small isolated plates near base of pectoral fin, post-ural plate at base of caudal fin large (plate length 17.0-20.3% HL), and total lateral plates 32-33 (modally 32). The new species occurs in a variety of habitats ranging from small, seasonally intermittent streams with clear water to large, turbid rivers over sand and mud substrates. It is sympatric with at least three other species of Loricaria in the Paraguay and lower Paraná drainages, including L. apeltogaster Boulenger 1895, L. coximensis Rodriguez et al. 2012, and L. simillima Regan 1904.

Obliteration of thermal springs by groundwater flows in sedimentary basins of Brazil

Analysis of geothermal and hydrogeologic characteristics of Paleozoic interior basins of Brazil has identified an association between the geographic distribution of thermal springs and areas of occurrences of groundwater flow. Specifically, thermal springs are found to be absent in regions inferred to have lateral flows of groundwater. This trend is evident in the basins of the Amazon region, in the central parts of the Parnaiba basin and in the west-central parts of the Parana basin. Model studies help to elucidate mutual exclusion of regions of thermal springs and sub-horizontal flows of groundwater. Numerical simulations indicate that groundwater flows with velocities ≥ 1 cm/year are capable of masking the occurrence of thermal anomalies. Also, down flow through distributed recharge zones can lead to development of large zones of relatively low temperature. The observational data sets of temperature gradients and Peclet numbers have been employed outlining advection-convection domains of subsurface strata in the sedimentary basins of the Amazon region, Parnaiba and Parana. Results obtained indicate that thermal buoyancy forces are incapable of overcoming advective flows in basins of the Amazon region. Similar conditions are also found to prevail in the central parts of the Parnaiba and Parana basins.

Remarks on sequence stratigraphy and taphonomy of the Malvinokaffric shelly fauna during the KAČÁK Event in the Apucarana Sub-basin (Paraná Basin), Brazil

The Eifelian–Givetian (Middle Devonian) transition constituted an important paleoenvironmental event for the Malvinokaffric Realm in the Apucarana Sub-basin (Parana Basin). This study highlights integration between taphonomy and sequence stratigraphy, and four depositional sequences are identified during the transition. In Sequence 1, the presence of a typical normal-sized Malvinokaffric fauna is recorded. In the transgressive systems tract (TST) of Sequence 2, no benthic fossils are present, and this is interpreted as a stratigraphic marker of an event of significant paleoenvironmental change (KACAK Event). In Sequence 3, the TST has abundant bioclasts, which become rarer toward the top of the section, i.e., within the transgressive systems tract. The original habitat of this autochthonous to parautochthonous fauna was a low-energy environment between the fair weather wave base and the storm wave base of the Devonian epicontinental sea. In the highstand systems tract of this sequence, the presence of normal-sized Pennaia paulianna and lingulids demonstrates the return of more ambient conditions. Sequence 4 is of Carboniferous age. Its limit is a second-order sequence boundary recording a lowstand systems tract formed by a fluvial depositional system. The low diversity and the disappearance of taxa are not the result of a taphonomic bias, but reflect the post-KACAK Event.

Clay mineral formation on Mars: Chemical constraints and possible contribution of basalt out-gassing

We focus on processes possibly occurring on Mars that could affect sufficiently large volumes of rocks to be detected by remote sensing techniques.When compared with the chemical modelling of water–rock interactions, the petrographic and mineralogical characteristics of clay deposited in the prismatic joints of a lava flow from the Parana basin (Brazil) suggest that the clay fraction of lava flows may be formed at least partly during an early post-magmatic stage associated with the degassing of acid volatiles.In view of the literature concerning other contexts, such as meteorites or experimental syntheses, we conclude that the crystallization of anhydrous mafic minerals and the formation of clay mineral are not systematically mutually exclusive phenomena. While clay formation is generally related to chemical reaction pathways, it is not necessarily due to the alteration of pre-existing silicates.Such post-magmatic reactions, even if they are likely to represent only a minor contribution to Martian clay formation limited to early Noachian times, require much lower amounts of water compared to conventional hydrothermal alteration or weathering systems. The products of these reactions can be detected over large surface areas, as in the case of the Mars sites, thus allowing us to envisage a greater diversity of paleogeographic scenarios for Early Mars.

Uncertainty Analysis in the Joint Inversion of Receiver Function and Surface-Wave Dispersion, Parana Basin, Southeast Brazil

The joint inversion of receiver function (RF) and surface-wave dispersion data is popular because it reduces the nonuniqueness of the modeled subsurface- seismic velocities. Whereas various inverse procedures have been used in joint subsur- face imaging, the evaluation of uncertainties in the estimated parameter distribution is usually overlooked or considered qualitatively. We present a quantitative method for determination of uncertainty in velocity models estimated by the joint inversion of RF and surface-wave data by using the prediction of each observation sample to map the objective-function surface and create a statistical distribution of estimated model parameters. The proposed methodology is evaluated in a controlled test using syn- thetic data simulating a realistic shear-wave velocity model. We then apply the method to field data recorded at the POPB seismic station in the Parana Basin, southeast Brazil. The respective range of uncertainty for modeled S-wave velocity distribu- tions in the synthetic and field tests were 0:111-0:412 km=s (2.5%-9.2%), and 0:110-0:341 km=s (2.5%-7.9%).

Filiação entre arenitos da formação Guará e sua cobertura pedológica no Rio Grande Do Sul

As regiões oeste e sudoeste do Rio Grande do Sul, RS, destacam-se pela ocorrência de extensas áreas com solos frágeis desenvolvidos sobre sedimentos arenosos continentais do Mesozoico da Bacia do Paraná. O uso inadequado das terras tem acelerado o processo de arenização sobre essas áreas. Nesse caso, o conhecimento dos solos é fundamental para a seleção de práticas adequadas de manejo visando a sua sustentabilidade. Os objetivos deste trabalho foram entender a evolução e estabelecer a relação, em termos de filiação, entre a rocha e sua respectiva cobertura pedológica por meio de perfis desenvolvidos sobre os arenitos da Formação Guará no RS. Foram realizadas análises químicas, físicas, mineralógicas e morfológicas em dois perfis de Cambissolos Háplicos e um perfil de Argissolo Vermelho. Verificaram-se indícios de adição externa de materiais aos perfis estudados, principalmente ilmenita, oriunda da alteração de áreas com rochas vulcânicas básicas circunvizinhas. O aporte de material alóctone nos perfis estudados é responsável pela pedogênese de horizontes B com incremento de argila, característicos de Argissolos e Cambissolos. Os dados sugerem a identificação e interpretação de um sexto componente pedogenético definido como contexto geológico do entorno.