The role of Quaternary geological studies in terroirs.

BELMONTE M.; MOREIRAS S.M.

Mendoza

Workshop; Coloquio Internacional Patrimonio, turismo y valorización de los territorios de la vid y del vino.; 2018

UNCU-UNESCO

From the knowledge that climate, parental material, and time force the soil development; we have realized the key importance of these soil forming parameters. However, though the time those studies addressed to climate conditions (altitude, hillslope orientation, daily sun exposition, among others) were winning markedly preference. It is a fact that first Geographical Identification (IG) in our country mentioned an extensive region with those main climate conditions. Far away, the IG studies were progressing being related to a restrict valley or locality, but nonetheless terroir studies continuing to be strongly related to climatic and topographic aspects. For that reason we focus our terroir studies on a new approach concerning the origin of Quaternary deposits where our secondary soils are normally developed. In our case studies, we initially interpret the genesis of soils (alluvial, glacial, fluvial, colluvial, etc.) based on stratigraphic studies (facies); then horizon sequence is described on soil profiles, where present boulders`lithologies are revealed. So we combined pedological studies with geological, stratigraphic and geomorphological approaches. We found that metamorphic rocks and granites are very common lithologies in some soils such as Altamira and Los Àrboles; while Paleozoic sedimentary rocks are main component in Precordillera terroirs (e.g. Acequión). However the age of our soils is very dissimilar. According to carbonate content and weathering degree of greater boulders we could estimate the age of soils. The eldest Pleistocene soils are related to a IV Gile`s carbonate stage showing a broad covert of carbonate on boulders or matrix. Following this idea, cemented horizons (K) are present in Middle-Late Pleistocene soils. In this way our studies reveal the complex history of our soils considering their genesis and evolution since more than thousands of years. Hitherto, taking into account the time factor, the role of regional climate is limited as main weather conditions could be switched during the soil development, especially in those soils sourced in Last Maximum Glacial around 20 thousand years ago. These findings are a key for affronting unquestionable climate change.