Mapa Litoestratigráfico Da Parte Oriental Da Bacia Bauru (Pr, Sp, Mg), Escala 1:1.000.000

Abstract

A Bacia Bauru é uma bacia continental interior do Neocretáceo (Coniaciano-Maastrichtiano), desenvolvida no centro-sul da Plataforma Sul-Americana. Acumulou uma seqüência sedimentar essencialmente arenosa, que ocorre em área de cerca de 370.000 km2. Tem por substrato rochas vulcânicas, sobretudo basaltos da Formação Serra Geral (Cretáceo Inferior). A área do mapa corresponde à parte oriental da bacia, com cerca de 180.000 km2. A seqüência neocretácea é composta por dois grupos cronocorrelatos: Caiuá (formações Rio Paraná, Goio Erê e Santo Anastácio) e Bauru (formações Uberaba, Vale do Rio do Peixe, Araçatuba, São José do Rio Preto, Presidente Prudente e Marília, incluindo os Analcimitos Taiúva). LITHOSTRATIGRAPHIC MAP OF THE BAURU BASIN EASTERN PART (PR, SP, MG), SCALE 1:1.000.000 Extended Abstract The Bauru Basin is a Late Cretaceous (Coniacian-Maastrichtian) interior continental basin developed as a result of subsidence of the central-southern part of the South-American Platform. It spreads over an area of approximately 370,000 km2 and is filled by a sandy sequence with a preserved maximum thickness of 300 meters. The substratum is made up of volcanic rocks (mainly basalts) of the Serra Geral Formation (Early Cretaceous). The map area corresponds to the eastern part of the basin, with about 180,000 km2 (west of São Paulo, southwest of Minas Gerais, northwest of Paraná), located between the coordinates 18°S to 25° S and 47° W to 54° W (Figure 1). The Upper Cretaceous sequence is composed by two partially contemporaneous groups (Figure 2): Caiuá (Rio Paraná, Goio Erê and Santo Anastácio formations) and Bauru (Uberaba, Vale do Rio do Peixe, Araçatuba, São José do Rio Preto, Presidente Prudente, and Marília formations, including the Taiúva analcimites). The intensification of the tectonic activities at the north-northeastern and eastern margins, and probably also at the northwestern margin, caused significant changes in the paleogeographic scenario, promoting progradation of alluvial fans. At the same time, climatic changes increased the humidity in the marginal zones. These changes mark the beginning of the sedimentary phase during which important fluvial systems from northeast to southwest were established between the marginal zone and the inland Caiuá Desert. During the uplift of the margins, the intrusion of several alkaline magmatic bodies cause extrusive magmatism near the eastern border (Taiúva analcimites), as well as localized silicification in the southern border. All known fossil occurrences are located in the eastern part of the basin and were paleogeographically controlled. They comprise bone remains, mainly from reptiles -crocodiles, turtles, dinossaurs -, as well as amphibians, fishes, mollusks, crustaceans, and oogones of charophytic algae. The main occurrences are from fluvial flood plain deposits and ephemeral lagoons in the interior of the basin, as well as from those of braided water flows and lagoons located in zones of marginal alluvial fans. In the interior of the basin the hot desertic condition prevailed during the two phases of sedimentation.

Micromorphology of Paleosols of the Marília Formation and their Significance in the Paleoenvironmental Evolution of the Bauru Basin, Upper Cretaceous, Southeastern Brazil

“…However, there are two different views on the lithostratigraphic position of these two groups. Authors such as Coimbra (1996, 2000) and Fernandes (2004) argue that the two groups are contemporary. Other authors (Fulfaro and Perinotto, 1996;Paula and Silva et al, 2005;Batezelli, 2010Batezelli, , 2015 put the Caiuá Group in the lower portion of the basin, separated from the Bauru Group with a stratigraphic unconformity, signaled by a very evolved paleosol (Geossol Santo Anastásio) highlighted by Fulfaro et al (1999).…”

Fossils of titanosaurs (Dinosauria, Sauropoda) from a new outcrop in Triângulo Mineiro, southeastern Brazil

“…The fossils described here were collected in an outcrop located about 5 km NE of the city of Veríssimo, 30 km W of Uberaba (Figure 1). The lithologic and geomorphologic features of the outcrop, with several tabular strata capped by carbonatic sandstones interbedded with massive pink sandstones, suggest that it correlates with the Echaporã Member of the Marília Formation (Fernandes & Coimbra, 2000), a geological unit that is also exposed in the vicinity of Prata, located northwest of the location presented here (Goldberg, 1995;Fernandes, 2004).…”

The mineralogy of paleosols in the Marília Formation and their importance in the environmental evolution of the Maastrichtian of the Bauru Basin in southeastern Brazil

“…The lithostratigraphic position of these two groups is up for debate. Authors such as Fernandes & Coimbra (1996, 2000 and Fernandes (2004) state that the two groups are contemporary. Other authors (Fúlfaro & Perinotto 1996, Paula e Silva et al 2005, Batezelli 2010, 2015 put the Caiuá in the lower portion of the basin, separated from the Bauru Group with a stratigraphic discordance.…”