Sedimentary evolution of distributive fluvial systems within intraplate tectonic active basins: Case study of the Early Cretaceous Araripina Formation (Araripe Basin, NE Brazil)

Author(s)

Warren, V, Lucas ; Martins de Andrade, Andre Santiago ^[1] ; Varejao, Filipe Giovanini ^[2] ; Promenzio, Paloma ^[1] ; Santos, Mauricio G. M. ^[3] ; Alessandretti, Luciano ^[4] ; Assine, Mario Luis ^[1]

Affiliation

^[1] Warren, Lucas, V, Sao Paulo State Univ, Dept Geol, IGCE, Ave 24A, 1515, BR-13506900 Rio Claro, SP - Brazil

^[2] Univ Fed Ouro Preto, Sch Mines, Dept Geol, BR-35400000 Ouro Preto, MG - Brazil

^[3] Fed Univ ABC, CECS, Ave Estados 5001, BR-09210580 Santo Andre, SP - Brazil

^[4] Univ Fed Uberlandia, Geog Inst, Rodovia LMG 746 Km 01, BR-38500000 Monte Carmelo, MG - Brazil

• Document type: Journal article
• Source: Journal of South American Earth Sciences; v. 111, NOV 2021.
• Web of Science Citations: 0

Abstract

The Lower Cretaceous Araripina Formation records deposition in a distributive fluvial system that is a part of the post-rift sequence of the Araripe Basin, NE Brazil. Following the opening of the Brazilian Equatorial Margin, the reactivation of regional faults of the Paleoproterozoic basement resulted in tectonic subsidence and formation of a regional-scale DFS. The Araripina Formation is an up to 40-m-thick succession of rhythmically interbedded sandstone and mudstone, organized in two depositional sequences separated by a regional disconformity. We recognized and grouped nine sedimentary facies into six facies associations that we interpreted as deposits of meandering channels, ribbon channels, minor channels, floodplain, lateral and terminal splays, and distal floodplain. The lower sequence facies associations suggest deposition in the medial to distal part of a distributive fluvial system in a tectonically active, interior basin subjected to episodic flooding. The periodic inundations were responsible for activating ephemeral channels and producing sheetfloods, followed by deposition of lateral and terminal splays in distal flooded areas. Syn-sedimentary deformation structures are present in rhythmite facies (truncating surfaces, load structures, injectite and convoluted folds) in the upper part of the lower sequence. The upper sequence was formed after a period of intense tectonic activity in a large distal floodbasin dominated by suspension. The deposition culminates in an interval with pedogenetic deposits cross-cut by a regional disconformity with the upper Exu Formation. Paleocurrent data from both depositional sequences indicate paleodepositional slope towards southeast and east with source-areas located to the northwest and west. This pattern is similar to that observed in the lower Santana Group and opposite to the westward direction of sedimentary transport in the overlying Exu Formation implying significant change of source region, basin topography and continental paleodrainage in the Araripe Basin after the Albian. (AU)

• FAPESP's process: 14/00519-9 - Centralities of night-time leisure in the city of São Carlos-SP and the interface relations
• Grantee: Tiago Ferreira Lopes Machado
• Support Opportunities: Scholarships in Brazil - Scientific Initiation