The Geodiversity of Brazil: quantification, distribution, and implications for conservation areas

Abstract

<p>Research related to the assessment of Geodiversity is highly relevant both at the international and national levels, especially in the last 20 years. These researches aim at valuing abiotic aspects as inseparable components of natural heritage and, thus, as well as Biodiversity, must be understood and valued through the ordering of their use and Geoconservation. Geodiversity studies are developed on the basis of several approaches, from the broadest ones, which contemplate the measurement of abiotic elements in a full way, to those that assess Geoheritage through the values ​​of Geodiversity. The present research follows the broader approach of the evaluation and analysis of the entire Geodiversity, applying the measurement of abiotic elements without their valuation, with the purpose of the spatialization of areas with greater and lesser density of the selected elements related in this research to lithology, relief and soil. For this purpose, bases produced by systematic surveys of national research institutions such as the Brazilian Institute of Geography and Statistics (IBGE) and the Geological Survey of Brazil (CPRM) were used. As a result, the mapping of the subindexes was obtained pointing from the division into 5 classes, the areas that present greater and lesser diversity of each element, as well as the synthesis map for the indexes of Geodiversity elements in Brazil, considering the three elements selected for this mapping. A spatial analysis was also carried out between the Geodiversity Index Map and the Brazilian Conservation Units, as well as the areas where Geopark Projects are being developed. The majority of the Brazilian territory presents low Geodiversity index (32%), followed by medium (28%), very low (17%), high (15%) and very high (8%). The higher indexes are found in ancient Orogenic Belts, associated with Crystalline Basement that shows broad variation of rocks, in some cases linked with soil and relief elements. Areas of medium diversity are concentrated in Cratons and Sedimentary Basins borders, and low diversity areas are found in the central regions of large Sedimentary Basins, as well as in the Pantanal Floodplain. The Conservation Units present the following percentage of Geodiversity index: very high: 12%; high:10%; medium 16%; low: 23%; very low 22%. The analysis was done taking into account the categories of Conservation Units as well, and the higher indexes were found in Natural Monuments and Wildlife Refuges (38 and 43% respectively). 8 geopark projects have predominance of very high and high Geodiversity indexes; 7 presents medium index and only one amongst the 16 presents predominance of low index. No geopark project has very low index predominant in territory. The analysis of the spatialization of the indexes was carried out from a descriptive and genetic perspective, aiming at clarifying the causes of the distribution of the abiotic elements in the Brazilian territory, being able to provide subindexes for studies in the scope of environmental services, nature and territory conservation planning.</p>