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GEOCHRONOLOGYOFTHEBASEMENTROCKSOFTHESOUTHERN PORTION OFTHEARAGUAIA BELT-PARAISO DoT7CANTINSREGI1Neõ)-nå""ntgããcnronotoglcal studiesofthebasementorthogneisses.ofthenorthernregionoftheAraguaiabelt s¡owed t¡e occurrence of Uottìîrcnàân ti.'SS Cal ona ÉutiyÞioie.ozoic (1.85 Ga) ro-ckslThe oldest-gneisses were grouped in the Colmeia Complex, the younger were named the Cantão Gneiss. Ií the southerÀ poltion of.the Araguaia bè]t, the basement sequences include metavulcanic-sedimentary r""tr,"iòt1¿fiìi", ãoi.-rili"ot", and alkaline gneissei, and granitic rocks. All of these sequences have been considered ;Ã."È;l;;t", otit òúgrt tt"Ë"á"fti""ór"gical dara â." ouoiiãui" t"o.test this hyp"othesis. The rnetavolcanic-sedimetrtary rocks are included i'i;h¿ Ri;ã;C"ã c,oupl*ttii"-rtr" gioniii"ioCts are lepresented by the_SeLroteâird Matança grani,9, :h:-,oli]llit and calc-silicate gneisses were grouped with Colnieia and Rio-dos Mangues.Complexes, aud the alkaline gneisses. in the Molìte Santo Sulte' iÀàir-!-,ijiii"i *"i" iiruéruËãt;-t"*il;i;ñgi.ruy ¡y "'leté ii..on Pb-eiaporation methods in order to define their stratigraphic inrerelarionships, and to contrilbìrte to-o gìiàiåi:ui,ã".itoí¿iúg ói?rtà geological. evoiutiorì of this crustal segment. The single zircon ages of the ið"árliii-^"Jiãi"-.ili.ot" gn"ir* ;;'ù; ú;;" 1.8 and 2f Ga

This article shows the tectonic influence of the Parnaíba River Lineament located in the Parnaíba Basin through a paleontological finding of a Cretaceous age close to a Permian sequence. The studied region is in the northeast of the State of Maranhão, near the town of Duque Bacelar, in the vicinity of the lineament. A normal fault in the NNE-SSW direction was responsible for the lowering of the Itapecuru Formation strata (Cretaceous) and the relative upward movement of the Pedra de Fogo Formation (Permian). The unprecedented finding of a Mesozoic (mid-Cretaceous) theropod tooth located topographically at the same level as a Paleozoic unit represents evidence of tectonic activity affecting the stratigraphic successions of the Parnaíba Basin. Keywords: Parnaíba River Lineament, Pedra de Fogo Formation, Itapecuru Formation, Spinosauridae.