Geological Heritage of the Três Barras Farm section, Ordovician-Silurian record in the Paraná Basin, Brazil

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Ana Beatriz Furtado Carvalho
https://orcid.org/0000-0001-9592-9573
Rodrigo Rodrigues Adôrno
Lívia Cardoso da Silva Rodrigues
https://orcid.org/0000-0003-0369-0425
Carolina Zabini

Abstract

The Três Barras Farm section is an outcrop located at the northern border of the Paraná Basin, in Midwest Brazil. Rocks of the Ordovician-Silurian age are found in this section, represented by the Iapó and Vila Maria formations of the Rio Ivaí Group, which directly overlay the crystalline basement. The Devonian rocks of the Furnas Formation are also observable at the top of the Três Barras section. Although the first fieldwork conducted there dates back to 1985, the section has been visited by different generations of researchers, often executing paleontological studies. The fossil record in this section comprises invertebrates such as mollusks and brachiopods, mineralized microfossils such as ostracods, and palynomorphs such as acritarchs and cryptospores. The different analyses conducted until the 2000s yielded a Lower Silurian age to the section's complete Vila Maria Formation strata, and no invertebrate fossil records were reported. Since then, much of the knowledge regarding the Rio Ivaí Group and the Três Barras Farm section has evolved. Recent work has questioned the assigned Silurian age, and fossil ostracods and brachiopods indicate the Hirnantian age to the Iapó and Vila Maria formations strata. Recent palynological research reported palynomorphs in the Iapó Formation for the first time, and the overall assemblage endorses the post-glacial paleoenvironment interpretation. Significant knowledge gaps persist despite notable advancements in understanding the palaeobiodiversity of the Iapó and Vila Maria formations, particularly due to recent discoveries at the Três Barras Farm. International correlation studies, especially in coeval basins of the Gondwana, need to be conducted to reinforce the chronobiostratigraphic repositioning of the upper portion of the Rio Ivaí Group on the north flank of the Paraná Basin.

Article Details

How to Cite
Furtado Carvalho, Ana Beatriz, Rodrigo Rodrigues Adôrno, Lívia Cardoso da Silva Rodrigues, and Carolina Zabini. 2024. “Geological Heritage of the Três Barras Farm Section, Ordovician-Silurian Record in the Paraná Basin, Brazil”. Journal of the Geological Survey of Brazil 7 (SI2). https://doi.org/10.29396/jgsb.2024.v7.SI2.4.
Section
Special Issue - Brazilian fossiliferous sites with paleobiological importance
Author Biographies

Rodrigo Rodrigues Adôrno, Geological Survey of Brazil

Center of Applied Geosciences

Carolina Zabini, UNICAMP

Department of Geology and Natural Resources