POST-EVENT FIELD TRIP

THE FIRST AND LARGEST RIVER SYSTEM IN THE PARNAÍBA BASIN, NORTHEAST REGION OF BRAZIL.

Leaders: Prof. Dr. LUIZ SATURNINO (UnB), Prof. Dr. GIORGIO BASILICI (UNICAMP)

Description:
We are pleased to invite participants of the 13th ICFS to explore the extensive Silurian fluvial system of the Parnaíba Basin (BP). This field trip offers the opportunity to learn about the deposits of the large braided fluvial system from the Ipu Formation, the basal unit of the Ordovician-Silurian Sequence that triggered the sedimentary infill of the BP. The Ipu Formation is composed of stratified sandstones, massive and stratified conglomerates rich in quartz pebbles, interpreted as deposits of braided rivers and alluvial fan systems. Its maximum thickness is 300 m, in the northeastern sector of the basin. There are records of polymictic diamictites in this unit, interpreted as proximal glacial deposits, possibly related to the Upper Ordovician glaciation, observed in the northern Gondwana basins. Participants in this field trip will have access to the best outcrops of the Ipu Formation in the Serra da Capivara, on the southeastern margin of the BP. This is a coarse-grained trough cross-stratified sandstone in the base abruptly shifting in the top to a polimythic clast-supported conglomerate with horizontal stratification (Capivara facies). These facies suggest a modification in the sedimentation regime, related to syntectonic alluvial fan deposits, with some glacial influence. Furthermore, as the Ipu Formation unconformably overlies the metamorphic basement of the basin, participants will have the opportunity to "touch" the large regional unconformity that marks the initiation of the sedimentary infill of one of the most didactic and exposed sedimentary basins on the planet.

In addition to its scientific focus, this field trip will introduce participants to the Serra da Capivara National Park (https://serradacapivara.org/english) a cultural sanctuary of prehistory with the world's greatest number of rock paintings and a UNESCO World Heritage Site (https://whc.unesco.org/en/list/606).

Logistics/recommendations:
The main airports in the US and Europe are just one stop away from São Paulo or Recife.

Once in Brazil, you should take a domestic flight to Petrolina Airport (PNZ) in Pernambuco.

Petrolina is located approximately 300 km from São Raimundo Nonato, already in the state of Piauí, from where the transfer of only 30 km to the Serra da Capivara National Park will take place.

The trip from Petrolina to São Raimundo Nonato takes between 4 and 5 hours of easy driving on paved roads.

The price includes:

· Translation from São Raimundo Nonato to the Park;

· 2x packed lunches;

The price does not include:

· Flight tickets;

· Cancellation insurance;

· Accommodation (click here https://capivara.stays.net/)

Dates: To be confirmed — 3 field days

Participants: Minimum 10 | Maximum 20
Cost: USD 850.00 / EUR 700.00 per participant

References:

Memória, S.C.; Netto, R.G.; Sedorko, D.; Andrade, L.S.; Vázquez-García, B. 2026. Impact of Late Ordovician glaciation on trace fóssil assemblages in Gondwana: a case study of the Serra Grande Group (Parnaıba Basin, NE Brazil). Front. Ecol. Evol. 14:1760723.

doi: 10.3389/fevo.2026.1760723

Assis, A.P.; Porto, A.L.; Schmitt, R.S.; Linol, B.; Medeiros, S.R., Correa Martins, F.; Silva. D.S. 2019. The Ordovician-Silurian tectono-stratigraphic evolution and

paleogeography of eastern Parnaiba Basin, NE Brazil. Journal of South American Earth Sciences 95. 102241. https://doi.org/10.1016/j.jsames.2019.102241.

Barros, J.S.; Ferreira, R.V.; Pedreira, A.J.; Guidon, N. 2012. Serra da Capivara (PI). In: Schobbenhaus, C.; da Silva, C.R. GEOPARQUES DO BRASIL: propostas. CPRM - Serviço Geológico do Brasil, Rio de Janeiro, v. 1: 493-542 p.