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| Author(s): |
Marcus Vinícius Theodoro Soares
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Geociências |
| Defense date: | 2022-04-27 |
| Examining board members: |
Giorgio Basilici;
Renato Paes de Almeida;
Luca Colombera;
Augusto Varela;
Marco Benvenuti
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| Advisor: | Giorgio Basilici |
| Abstract | |
Fluvial facies models are vastly based on models of tributary rivers under humid climates. However, state-of–art in fluvial sedimentology demonstrates that the majority of the stratigraphic record is composed of distributive fluvial systems (DFS). As a consequence, this approach, focused a priori over a restrict fluvial end-member, establishes a deficient ground to comprehend ancient distributive fluvial systems. In particular, dryland distributive fluvial systems because the current approach does not account for their incredibly complex spatio-temporal variability, resulting in depositional models of poor stratigraphic resolution. Current challenges in fluvial sedimentology rely on the investigation of palaeoclimatic factors that control the dynamics and stratigraphic organisation of ancient distributive fluvial systems. DFS models are focused primarily on palaeohydraulic reconstructions from sediments, with little or no attention to palaeosols. This method results in great disadvantage to the scientific community with loss of valuable palaeoenvironmental and stratigraphic information that palaeosols preserve. Due to the absence of models that include palaeosols, this doctoral thesis focuses on the sediment-palaeosol interaction in ancient distributive fluvial systems and involves sedimentary successions from the Bauru Group, southeast Brazil. The successions were developed during the Upper Cretaceous at the margins of the sedimentary basin under dryland conditions, allowing the study on the interaction of sediments-palaeosols for ancient distributive fluvial systems. The main objective of this doctoral thesis was to apply information from palaeosols and clastic sediments as palaeoenvironmental and stratigraphic proxies. In particular, to verify how palaeoclimatic, palaeomorphologic, temporal, and sediment supply information (from palaeosols), as well as depositional processes and their controlling factors (from sediments), governed the sedimentary processes and depositional dynamics of ancient distributive fluvial systems. The study presented in this thesis allowed: (i) to understand cyclic variations in internal architecture of fluvial channels encountered at proximal DFS zone reflect climatic variations and act as robust palaeoclimatic proxies on the study of environments of high sedimentation rates; (ii) to identify geomorphologic cycles in the stratigraphic organization of DFS; (iii) to propose the Serra da Galga Formation as a new lithostratigraphic unit, on the northeastern margin of the Bauru Basin, based on the genetic interpretation of a DFS; (iv) to develop a palaeopedosedimentary model able to recognise the palaeoenvironmental factors controlling the sedimentary and palaeopedogenetic processes in these intricate systems considering their downdip and alongstrike dynamics; (v) to reconstruct the basin-scale palaeosol-landscape relationships and to unravel the autogenic and allogenic factors controlling their genesis, distribution and pedostratigraphic arrangement in the stratigraphic record (AU) | |
| FAPESP's process: | 18/10574-8 - Distribution of sediments and palaeosols in ancient distributive fluvial systems: proxies for palaeoenvironmental and stratigraphic interpretations |
| Grantee: | Marcus Vinícius Theodoro Soares |
| Support Opportunities: | Scholarships in Brazil - Doctorate |