Sediment distribution model in marine shelf area: a cambrian example from the Sergipano Belt (Lagarto Formation, Estancia Domain, Sergipe)

Author(s)

Pedro Henrique Vieira de Luca

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Mecânica
• Defense date: 2008-08-21

Examining board members

Giorgio Basilici; Ticiano José Saraiva dos Santos; Andre Oliveira Sawakuchi

• Advisor: Giorgio Basilici

Abstract

Coastal areas of wave-influenced tidal plains are not well known in recent and ancient depositional systems. The Lagarto Formation represents one of these mixed depositional systems influenced both by tide and wave activities. This work describes the sediments in this system, interprets the depositional processes and defines a distributional model of sediments to the Lagarto Formation. The Lagarto Formation belongs to the Estancia Domain, Sergipano Belt, outcropping in Bahia and Sergipe states. It has been recognized six lithofacies, which composes three architectural elements: Upper intertidal deposits. Intermediary intertidal deposits e Lower intertidal deposits. The architectural elements are generated by the inter- relation between tide and oscillatory processes (fair-weather and storm waves). It has been recognized two main processes of horizontal distribution of sediments. In the first case, the sediments are transported by unidirectional flows derived from tide currents (ebb and flood flows). In the second case, the sediments are eroded and transported from the distal to the proximal portion by oscillatory or combined flows developed from storms episodes. There are a fining (from fine and medium-fine sand in the lower intertidal to mud and very fine sand in the upper intertidal area) and thinning of the sandy beds landward. It has been attributed a transitional depositional system to the Lagarto Formation, developed in an Open Coast Tidal Flat (AU)