Excerpts from the 6th Latin American Congress of Sedimentology

Abstract

. This is the main scientific event focused on the Latin American community of sedimentologists and stratigraphers, promoted under the seal of IAS, the International Association of Sedimentologists, since 1997. The VI LACS had 380 registrations: 251 from Brazil and 129 from 17 other countries, mainly of South America. There were 121 presented works, which integrated the abstracts book. After the event, the authors were invited to submit a full paper version of theirs abstracts to the Annals of the Congress, which is being published now as this special supplement of the Brazilian Journal of Geology, with financial support from the Brazilian National Council for Scientific and Technological Development -CNPq (Grant 452723/2013-2).The seven papers of this special supplement are ordered accordingly the age of the sedimentary succession analysed, from the Proterozoic to the Holocene. In the first article "Unusual thick eolian sand sheet sedimentary succession: Paleoproterozoic Bandeirinha Formation, Minas Gerais", Fábio Simplício and Giorgio Basilici deal with an eolian sand sheet sedimentary succession with anomalous (more than 50 m) thickness, related to the first rift stage of Espinhaço Basin evolution. The authors discuss the sedimentary conditions, as early cementation near the surface, necessary to promote the prolonged formation only of protodunes (dunes without slipfaces).The second article "Modelling a glacier advance-retreat cycle in the upper Devonian Cabeças Formation, eastern Parnaíba Basin, Brazil", by Barbosa et al., reports glaciotectonic features that represent the first evidence of the Fammenian glaciation in the southeastern border of the Parnaíba Basin, Northern Brazil. The authors define three facies associations (deltaic front, subglacial deposits and melt-out delta front), each one representative of a depositional phase in a glacier advance-retreat cycle, and show the wide variety of deformational structures produced in each phase.In the third article "Diagenesis reaction geochemical modelling of Snorre Field sandstone reservoir using comparative code results", Klunk et al. compare the results of three computer geochemical models (Dissol-thermal, Gwb and Toughreact), used to predict diagenetic processes (precipitation versus dissolution of minerals) based on thermodynamic and kinetic parameters. The models are applied to data from a same reservoir sandstone of the North Sea. The authors show that the found differences among the results from the three models depend on the temperature interval, with tendency to decrease at higher temperatures.In the fourth paper "The Cogollo Group and the Oceanic Anoxic Events 1a and 1b. Maracaibo Basin, Venezuela", Dot et al. (PDVSA) deal with the broader calcareous platform system of the Maracaibo Basin. Based on sedimentological and organic geochemistry data from six cores, the authors propose two beds of petroleum source rocks, additional to the well-known and main source rock of this basin, the La Luna Formation. These two beds are correlated to the amplific...