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Metamorphic degassing from active collisional orogens supplies a significant fraction of CO2 to the atmosphere, thus playing a fundamental role even in today’s Earth carbon cycle. Appealing clues for a contemporary metamorphic CO2 production in active orogens are represented by the widespread occurrence, along the whole Himalayan belt, of CO2 rich hot-springs mainly localized along major tectonic discontinuities. In contrast to these well-studied hot-springs, almost no chemical and isotopic data are actually available for cold-springs, especially for those located at high-altitude and in remote areas of the Himalayas. In the framework of the Ev-K2-CNR SHARE (Stations at High Altitude for Research on the Environment) Project, we have started a preliminary chemical and isotopic study on high-altitude cold-springs located at different structural levels in the eastern Nepal Himalayas. Chemical and isotopic data obtained from the high-altitude cold-springs are compared with those obtained by previous authors from hot-springs located along the MCT. The isotopic signature of stable isotopes of hydrogen and oxygen could help to identify the waters sources in the investigated Himalayan sectors, to individuate mixing phenomena between waters of different provenience and possible connection with different circulation nets. These first measurements on high-altitude springs from remote areas of eastern Nepal represent a first step towards a better definition of a reliable scenario of water resources availability and will contribute to the understanding of the water cycle in the studied area.

A number of studies suggest that mountain ranges have strong impact on the global carbon cycle; metamorphic degassing from active collisional orogens supplies a significant fraction of the global solid-Earth derived CO2 to the atmosphere, thus playing a fundamental role even in today’s Earth carbon cycle. The Himalayan belt, a major collisional orogen still active today, is a likely candidate for the production of a large amount of metamorphic CO2 that may have caused changes in long-term climate of the past, present and near future. Large metamorphic CO2 fluxes are facilitated by rapid prograde metamorphism of big volumes of impure carbonate rocks coupled with facile escape of CO2 to the Earth’s surface. So far, the incomplete knowledge of the nature, magnitude and distribution of the CO2-producing processes hampered a reliable quantitative modeling of metamorphic CO2 fluxes from the Himalayan belt. This study, integrated in the framework of the Ev-K2-CNR SHARE (Stations at High Altitude for Research on the Environment) Project, focuses on the metamorphic decarbonation processes occurring during the Himalayan collision. We hereby present preliminary results focusing on the distribution of different types of metacarbonate rocks in the Eastern Himalaya, their petrographic description and the first reported petrological data about the nature of the CO2-producing reactions in garnet-bearing calc-silicate rocks. These results represent a contribution toward a better understanding of the influence exerted by orogenic processes on climatic changes at global scale.

The Monviso Ophiolite Geopark (MOG) is one of the strategic geothematic areas chosen to represent the geodiversity of Piemonte within the research project “PROactive management of GEOlogical heritage in the PIEMONTE region”. The MOG is an extraordinary well preserved ophiolite body in the Italian Western Alps. It is one of the best known relics of oceanic crust in the Alps and formed during opening of the Mesozoic western Alpine Tethys and underwent high pressure metamorphism during Alpine subduction. The MOG encompasses the whole lithological spectrum of the Piemonte-Ligurian ophiolites, i.e. metamorphosed peridotite, gabbro, dolerite, basalt, and cover sediments. The MOG gives the almost unique chance for everybody to see and appreciate different portions of the ancient ocean along a mountain trail; from the Po river springs at Pian del Re, to Lago Fiorenza, Lago Lausetto and Lago Superiore, a path rises from 2,000 up to about 2,350 m a.s.l. and shows all different ophiolitic lithologies within few kilometers. The inventory of a number of different geosites at the MOG, whose conservation and development require different expertises, is considered as the first and essential starting point for the geoconservation of geological heritage and geosites.