320 BRAZIL wide To the south it is separated from the Brası´lia Belt by a basement block, which is affected by the north-east–south-west-trending Transbrasiliano Fault Zone; to the east and to the north it is covered by the sediments of the Palaeozoic Parnaı´ba Basin (Figure 9) The Archaean and Palaeoproterozoic basement is overlain by Neoproterozoic metasediments, which are the best exposed in the belt A 720 Ma ophiolite occurs within thrust sheets in the central portion of the belt Paraguay Belt The Paraguay Belt, the youngest member of the Tocantins orogenic system, is a pronounced salient on the south-eastern border of the Amazon Craton (Figure 9) Vendian glaciomarine deposits overlain by carbonates containing an Ediacaran fauna, together with continental foreland deposits, are the main units exposed in the belt Its overall architecture is characterized by a system of open to tight upright folds in the culmination zone of the large salient, which grade into two cratonwardverging systems of folds and thrusts at its northeastern and southern ends The deformation and metamorphism in the Paraguay Belt is estimated to have occurred between 550 Ma and 500 Ma and probably represents the last steps towards the final assembly of western Gondwana Brasilia Belt The Brası´lia Belt is an east-verging fold–thrust belt (1200 km long and up to 300 km wide) that fringes the Sa˜ o Francisco Craton to the west and south-west (Figure 9) The basement is an extension of the Archaean–Palaeoproterozoic substratum of the adjacent Sa˜o Francisco Craton In the internal zone, the Palaeoproterozoic basement received two Neoproterozoic accretions: an Archaean granite–greenstone terrane and a large magmatic arc (Figure 9) A suture zone juxtaposes the Rio de la Plata and Sa˜ o Francisco plates in the southern portion of the belt A 1770 Ma ensialic rift sequence, a thick Neoproterozoic passive-margin package, and deepmarine and probably ocean-floor assemblages are the main cover units Mesoproterozoic layered mafic–ultramafic complexes and foreland-basin sediments are also involved From a structural standpoint the Brası´lia Belt consists of two distinct compartments that join along the pronounced east–west-trending Pirineus syntaxis: an east–south-east-verging basement-involved fold– thrust belt to the north, and a system of spoon-shaped east–south-east-verging nappes to the south The Transbrasiliano Lineament, a north-east–south-westorientated dextral strike-slip fault zone, overprints the internal portions of both the Brası´lia and Figure 15 Stratigraphical chart of the Parana´ Basin showing the evolutionary stages and their genetic controls Note the corres pondence between depositional stages/unconformities and orogenic events in the Andean chain during the foreland stage Based on: (1) Zalan PV, Wolff S, Astolfi MA, et al (1990) The Parana´ Basin, Brazil In: Leighton MW, Kolata DR, Oltz DF, and Eidel JJ (eds.) Interior Cratonic Basins, pp 681 708 AAPG Memoir 51 Tulsa: American Association of Petroleum Geologists; (2) Milani EJ (1992) Intraplate tectonics and the evolution of the Parana´ Basin, SE Brazil In: De Wit MJ, Ransome IGD (eds.) Inversion tectonics of the Cape Fold Belt, Karoo and Cretaceous Basins of Southern Africa Rotterdam, Balkema, pp 101 108