Architectural model and evolution of a Mesoproterozoic ERG: Galho do Miguel formation

Abstract

Global distribution of Precambrian ERG systems is highly fragmented, making it difficult to understand the depositional systems developed during this period. The distinction between pre- and post-vegetation deposits, as well as the main factors that influenced the development and preservation of these strata, are still not well understood. Verify the wind influence of as a depositional factor in a vegetation-free landscape on the earth's surface is the aim of this project, which will study the Precambrian ERG sedimentary succession of the Galho do Miguel formation (Mesoproterozoic), Southeastern Brazil. This project includes (i) deposition processes interpretation; (ii) architectural model and depositional system definitions with the vertical (temporal) and horizontal (spatial) variations; (iii) sequential analysis of sedimentary succession and (iv) comparison with post-vegetation ERG models. To a better understand of these objectives, it will be necessary to determine some important aspects, which involves the recognition of the bedforms types, the manner of the accumulation of cross stratifications in ERG and the role of the water table as a controlling factor of accumulation and long-term preservation. In good exposures of the Galho do Miguel formation, represented by sedimentary successions of hundreds of meters with the variability of facies and possible evidence of wet or dump interdune areas, are indispensable tools for the sedimentological complexity understanding of Precambrian wind systems. Thus, this study will contribute to the discrimination of genetic models on the dynamics of recent and ancient ERG environments, as well as for the enrichment of the knowledge of the Serra do Espinhaço deposits and Precambrian wind sedimentary sequences. (AU)