Geo-environmental Evolutionary Interpretation of Geosites Analysed in La Quebrada de Humahuaca, Northwestern Argentina

Abstract

Geological heritage and geodiversity are distinguished in areas with a strong geological and cultural character, such as La Quebrada de Humahuaca (Humahuaca Ravine), in northwestern Argentina. The aim of this work is to recognise the geological heritage of La Quebrada de Humahuaca through the identifcation and analysis of geosites which, due to their features, integrate and represent the complex geology of the area and allow, by means of their assignment to various times and geological processes, an evolutionary interpretation of the ravine. This work, in addition to contributing to the research of the ravine geological heritage and enriching the studies of the region natural heritage, is supplemented with the robust cultural heritage already protected by numerous legal regulations in force. La Quebrada de Humahuaca is shaped by a deep valley of tectonic origin located in the geological province of the Cordillera Oriental Argentina (Argentine Eastern Mountain Range). From a geological point of view, it is a complex structure rich in its composition, since it has had a time development of about 600 Ma. From an archaeological viewpoint, human occupation dates back to more than 10,000 years B.C. In its extensive journey, there are numerous towns and places that have resulted from the link between various territories and cultures, which allowed it the title conferred by the UNESCO as a World Heritage Site in 2003. The list of geosites was carried out through the use of geological- and geographical-based literature and the observation of satellite images; the aforementioned information was integrated with the results of an opinion survey sent to recognised researchers with a work history in La Quebrada. Besides, numerous feld trips and in situ analyses of every geosite were efected. The set of the geosites allows us to identify the presence of geodiversity elements that illustrate a remarkable geological variety. Geosites are heterogeneous in time and in geological processes involved. Unconformities, thrusts, slope dynamics, diferential erosion, ancient levels of Rio Grande (a river), sedimentary basins, signifcant guide fossils at international level, and dinosaur footprints, among others can be found. These are the result of both endogenous processes, through the tectonic events that afected the Eastern Mountain Range, and exogenous processes of erosion. In terms of frequency, there is no repetition among the sites. Despite that, not all of the sites.