FIELD TRIP

Sedimentology of the Jurassic Guará Fluvial Megafan toward the Brazil–Uruguay Border

Leaders: Prof. Adriano Reis (UnB), Prof. Claiton Scherer (UFRGS), Prof. Ezequiel de Souza (Unipampa), and Erik Dario, MSc (UFRGS)

This field trip offers an overview of the diverse facies associations of the Guará Distributive Fluvial System (DFS), a Jurassic fluvial megafan with an estimated preserved depositional dip extent of approximately 1,050 km. The trip will focus on medial-to-distal transitions along a 300 km transect, highlighting two distinct fluvial styles, aeolian-fluvial interactions, and terminal splay deposits.

Field Trip Highlights:

- A comprehensive overview of the Jurassic fluvial record in South American intracratonic sedimentary basins;
- Fluvial facies and macroforms representing two distinct discharge regimes;
- Key examples of rare non-marine siliciclastic stromatolites;
- Late Jurassic dinosaur tracks;
- Special additional stop: outcrops of the Early Triassic Sanga do Cabral Formation, which preserve excellent examples of supercritical-flow structures in non-glacial fluvial deposits.

In addition to its scientific focus, this field trip will introduce participants to distinctive aspects of Pampean culture in southern Brazil and northern Uruguay. Participants will travel across open grassland landscapes shaped by ranching traditions, regional cuisine, and a long history of cross-border interaction. The trip will include the Brazil–Uruguay “Frontier of Peace,” where the twin cities of Santana do Livramento, Brazil, and Rivera, Uruguay, form a rare binational urban setting in which one can cross from one country to another simply by walking across a street or public square. This unique borderland culture is expressed in everyday life, language, food, and social traditions shared on both sides of the frontier. During the trip, participants will also have the opportunity to experience local food traditions, including Brazilian churrasco and Uruguayan asado/parrilla, as part of the region's shared gaucho heritage. The excursion may also offer a glimpse of the emerging wine culture of the Campanha Gaúcha, one of Brazil’s southern wine-producing regions, where vineyards, open plains, and frontier traditions create a distinctive cultural landscape.

Logistics & Recommendations

The field trip will begin and end in Porto Alegre, Rio Grande do Sul, Brazil. Participants are responsible for arranging their own travel to Porto Alegre, which is served by frequent daily flights from São Paulo and other major Brazilian cities. The excursion will be conducted as a round trip by private coach, travelling to western Rio Grande do Sul and the Uruguayan border.

Brazil is a continental-sized country, so several hours of road travel to and from the field areas will be necessary. Although the core field trip includes 5 field days, participants must arrive in Porto Alegre one day before the trip starts and depart one day after it ends to ensure the 5 field days can be fully used.

Cold weather is expected in the region during July, with temperatures dropping to around 5°C, especially at night and during windy or overcast days. The Minuano, a strong, dry, cold wind blowing from Patagonia, is a defining feature of the regional winter, although rain and high humidity are also common. Windproof and waterproof clothing is highly recommended. Participants should also bring sturdy field shoes or hiking boots suitable for uneven outcrop surfaces.

The field trip fee includes:

- Private coach transportation for the entire itinerary;

- 3 packed lunches during field days;

- 6 nights of accommodation, with breakfast included, in twin-share/double rooms.

The field trip fee does not include:

- Flights to/from Porto Alegre;

- Travel/cancellation insurance;

- Remaining lunches and dinners at local restaurants;

- Optional winery experience on the Brazil–Uruguay border (estimated cost 55 EUR) https://www.cerrochapeu.com/en/pages/wine-tourism .

Dates: To be confirmed — 5 field days + 2 days for arrival/departure
Participants: Minimum 10 | Maximum 25
Cost: USD 550.00 / EUR 475.00 per participant

References:

AMARANTE, FRANCYNE BOCHI DO ; Scherer, Claiton M.S. ; GOSO AGUILAR, CÉSAR ALEJANDRO ; REIS, ADRIANO DOMINGOS DOS ; MESA, VALERIA ; SOTO, MATÍAS . Fluvial-eolian deposits of the Tacuarembó formation (Norte Basin - Uruguay): Depositional models and stratigraphic succession. JOURNAL OF SOUTH AMERICAN EARTH SCIENCES, v. 90, p. 355-376, 2019. http://dx.doi.org/10.1016/j.jsames.2018.12.024

ANGONESE, BRUNO S. ; Scherer, Claiton M.S. ; DE ROS, LUIZ F. ; MICHEL, ROSSANO D.L. ; SIPP, GABRIEL S. ; FERRONATO, JOÃO P.F. . Desertic siliciclastic stromatolites in the Upper Jurassic Guará Formation from southwestern Gondwana: Trapping and binding in a non-marine setting. GEOLOGY, v. 52, p. 851-856, 2024. https://doi.org/10.1130/G52662.1

DOS REIS, ADRIANO DOMINGOS ; DOS SANTOS SCHERER, CLAITON MARLON ; OWEN, AMANDA ; DO AMARANTE, FRANCYNE BOCHI ; FORMOLO FERRONATTO, JOÃO PEDRO ; PANTOPOULOS, GEORGE ; DE SOUZA, EZEQUIEL GALVÃO ; BÁLLICO, MANOELA BETTAREL ; GOSO AGUILAR, CÉSAR ALEJANDRO . A quantitative depositional model of a large distributive fluvial system (Megafan) with terminal aeolian interaction: The Upper Jurassic Guará DFS in southwestern Gondwana. Journal Of Sedimentary Research, v. 92, p. 460-485, 2022. http://dx.doi.org/10.2110/jsr.2021.040

Scherer, Claiton M.S.; REIS, ADRIANO D. ; HORN, BRUNO L.D. ; BERTOLINI, GABRIEL; LAVINA, ERNESTO L.C. ; KIFUMBI, CARREL ; GOSO AGUILAR, CESAR . The stratigraphic puzzle of the permo-mesozoic southwestern Gondwana: The Paraná Basin record in geotectonic and palaeoclimatic context. EARTH-SCIENCE REVIEWS, v. 240, p. 104397, 2023. http://dx.doi.org/10.1016/j.earscirev.2023.104397

SCHERER, CLAITON M. S.; LAVINA, ERNESTO L. C. . Sedimentary cycles and facies architecture of aeolian-fluvial strata of the Upper Jurassic Guará Formation, southern Brazil. Sedimentology (Amsterdam. Print), v. 52, p. 1323-1341, 2005. http://dx.doi.org/10.1111/j.1365-3091.2005.00746.x

XAVIER, PEDRO L.A. ; SCHERER, CLAITON M. DOS S. ; REIS, ADRIANO DOMINGOS DOS ; SOUZA, EZEQUIEL GALVÃO DE ; GUADAGNIN, FELIPE ; PIÑEIRO, GRACIELA . Supercritical fluvial styles and the shifting aridity in the Early Triassic: the example of the Sanga do Cabral Formation, Paraná Basin, Brazil. Journal Of Sedimentary Research, v. 93, p. 972-1006, 2023. http://dx.doi.org/10.2110/jsr.2022.063