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The concept of geoheritage is related to places of geological interest, generally of aesthetic, cultural, socio-economic and/or scientific value. Many geosites are of karstic nature, because of their intrinsic beauty, their singularity and high geodiversity. Caves are among the most visited and economically exploited geological landforms. They constitute geosites as a whole, with their scenic landscapes, hydrogeological importance and the presence of bewildering natural rock and mineral formations including stalactites, stalagmites, flowstones and many other bizarre speleothem shapes. In some cases, a single speleothem, and the palaeoclimate record it contains, can be on its own of extraordinary importance to science. Once studied, these samples are often stored in research institution collections, rarely accessible to the wide public. In this paper, we report on the museumization of a stalagmite that has delivered a unique and exceptionally long glacial climate record from southern Italy, shedding light on the causes that led to the Neanderthal contraction and Modern Human expansion in this mild Mediterranean climate between 45 and 42 thousands years ago. The proposed museumization aims to demonstrate the potential of speleothems, after scientific application, in terms of educational and tourist resources. This approach allows to highlight the scientific importance of karst and cave geosites to the wide public, promoting their conservation and the valorisation of the studied cave-material.

In the present work, the mineralogical-petrographic and physical features of Middle Jurassic sandstones with macrofossil plant remains belonging to the Domenico Lovisato collection, housed at the Geological and Palaeontological Museum of the Cagliari University (Sardinia, Italy), have been studied to define the alteration processes and the consolidating treatment. These sandstones, coming from the Genna Selole formation (central Sardinia), show evident problems of physical decay, due to petrophysical and compositional characteristics such as high porosity, low cementing degree, and presence of clay minerals (e.g., phyllosilicates). This latter leads to subsequent cyclic mechanisms of hydration/dehydration, which affect these sedimentary rocks. For this purpose, five main different sandstone specimens with evident crystalline matrix decohesion have been selected and analyzed. To define their mineralogical-petrographic (composition, microstructure) and physical characteristics (real and bulk densities, helium porosity, water absorption, mechanical strength, etc.), the optical microscope (OM) in polarized light, X-ray powder diffraction analysis (XRPD), helium and water pycnometer, and point load test were used. Testing the most suitable and compatible products for consolidation and time-saving of the palaeobotanical remains, several experimental treatment tests have been performed using four chemical products (i.e., alkoxysilane ethyl silicates and Na/K-silicate).