Miocene paleoenvironmental changes in the Solimões Basin, western Amazon, Brazil: A reconstruction based on palynofacies analysis

We report palynofacies from two sections of Miocene Solimões Formation of the Solimões Basin, western Amazon, Brazil to better understand paleoenvironmental evolution. Based on cluster analysis, five palynofacies associations were recognized, dominated by either opaque, non-opaque, algae, miospores...

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Published in:Palaeogeography, palaeoclimatology, palaeoecology palaeoclimatology, palaeoecology, 2020-01, Vol.537, p.109450, Article 109450
Main Authors: Sá, Natália de Paula, Carvalho, Marcelo de Araujo, correia, Gabriel da Cunha
Format: Article
Language:English
Subjects:
Depositional environments
Marine incursion
Palynology
Sedimentary organic matter
Terrestrial facies
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Summary:We report palynofacies from two sections of Miocene Solimões Formation of the Solimões Basin, western Amazon, Brazil to better understand paleoenvironmental evolution. Based on cluster analysis, five palynofacies associations were recognized, dominated by either opaque, non-opaque, algae, miospores and structureless/marine organic matter. The distribution of palynofacies associations reflects a complex depositional system with fluvial, lacustrine, estuarine, and shallow marine environments. A high abundance of woody material indicates a fluvial-lacustrine-dominated environment. Three marine incursions were recognized, indicated by the presence of dinoflagellate cysts and microforaminifera test linings. Marine influence was more evident during the late Middle-Late Miocene interval, when transgressions occurred over a greater extent of the Amazon region. •Palynofacies are reported for Miocene rocks of Amazon Region.•Findings indicated fluvial, lacustrine, estuarine, and marine environments predominate.•Three marine incursions are identified: one in the Middle Miocene and two in the Middle–Late Miocene.
ISSN:0031-0182
1872-616X
DOI:10.1016/j.palaeo.2019.109450