Geomorphological analysis of coastal depositional systems in SE Brazil aided by Google Earth coupled with the integration of chronological and sedimentological data by means of a Google Fusion Table

Although the evolution of Brazilian coastal depositional systems in the Quaternary has been studied in past decades, it is only in the last couple of years that it has been possible to incorporate the latest remote sensing databases available to help understand their development. In comparison to other freely accessible imagery, high-resolution images available on Google Earth are advantageous when undertaking local coastal analysis. In some instances, it is possible to differentiate geomorphologic features such as tidal deltas, beach ridges, and dunes. Also, the monitoring of small-scale features allows evaluation of the sensitivity of coastal zones to high-frequency and low-intensity processes. Thus, the downscaling description of coastal zones is now easily accessible, permitting the analysis of the extensive Brazilian coastal depositional systems. On the regional scale, a quick glance of a coastal setting may help frame the sedimentary characteristics of the depositional system. Coastal areas in the States of Santa Catarina and Sao Paulo are taken into consideration in this study. These areas illustrate representative prograded barrier formations from Middle to Late Holocene with dunes formed at a later development stage. A comparison is made in the use of Google Earth and its historic images with aerial photographs and Landsat images. In the past, small-scale features of these regions were evaluated in aerial photographs, while regional features were studied by low-resolution satellite images. Accordingly, integration of these two products was difficult. In this work, we show that Google Earth facilitates the analysis as a whole. Furthermore, comparison of Google Earth images with aerial photographs from 1938 onward allowed the study of short-term migration and deflation of the dunefields probably accelerated in recent years by human interference. In addition, Keyhole Markup Language (KML) files were saved from Google Earth placemarks to facilitate georeferencing raster images on GIS programs. Finally, information available from previous local studies, such as luminescence dating, geomorphology of the costal system, grain size, heavy minerals, pollen, and carbon isotope analyses, was gathered into a Google Fusion Table database making data retrieval and parsing easily accessible. This database provides information that can be shared with other researchers and may be used to address important questions about the development of Brazil's coastal system in the past, present, and future.