Leonardo Piccini

Late Holocene drought responsible for the collapse of Old World civilizations is recorded in an Italian cave flowstone

A severe drought in parts of low-latitude northeastern Africa and southwestern Asia ∼4200 yr ago caused major disruption to ancient civilizations. Stable isotope, trace element, and organic fluorescence data from a calcite flowstone collected from the well-watered Alpi Apuane karst of central-western Italy indicate that the climatic event responsible for this drought was also recorded in mid-latitude Europe. Although the timing of this event coincides with an episode of increased ice-rafted debris to the subpolar North Atlantic, the regional ocean-atmosphere response seems atypical of similar Holocene ice-rafting events. Furthermore, comparison of the flowstone data with other regional proxies suggests that the most extreme part of the dry spell occurred toward the end of a longer-term climate anomaly.

The environmental features of the Monte Corchia cave system (Apuan Alps,central Italy) and their effects on speleothem growth

The Monte Corchia cave system, one of the most famous and popular caves in Italy, has in recent times been the subject of investigation on its speleothems as paleoclimate archives. This paper describes the geology, geomorphology and water chemistry of the cave system with the aim to elucidate the processes that have generated these speleothems and the properties they contain that are so useful for paleoclimatology. Some general conclusions can be drawn: i) the Corchia system is a cave developed over different altitudes during progressive uplift of the mountain chain in which it is located, probably under drainage conditions very different to those of the present. This has allowed the development of a large (ca. 60 km) and deep (-1187 m) karst system; ii) the dewatering phases have left the deepest chambers far away from clastic input and with long drip pathways; iii) the peculiar geological context has permitted the water to intercept and dissolve a significant source of U (still unknown) that facilitates radiometric dating; iv) in the last 1 Ma at least, no significant changes have occurred in the relief and in the epikarst, in the sense that speleothems have grown under very similar conditions. In addition the extremely low Ca concentration of drip waters have permitted low speleothem growth rates and, at least for the “Galleria delle Stalattiti”, the zone under paleoclimate studies,a stable plumbing system (i.e. chemistry and stable isotopes of drip waters) has produced calcite close to isotopic equilibrium.

The polygenetic caves of Cuatro Ciénegas (Coahuila, Mexico): morphology and speleogenesis

Abstract: Received 3 April 2007; Revised 14 May 2007; Accepted 21 May 2007 this goal, the “La Venta” Geographical Association performed a study from 1999 to 2003 (Bernabei et al., 2002; Forti et al., 2003). This paper describes the geomorphic aspects of karst landforms and caves surveyed during the field investigation, which testify to an ancient bathyphreatic regional flow of thermal and meteoric waters, probably similar to that which feeds the present springs (Forti et al., 2004b). STUDY AREAGeographical features The Sierra Madre Oriental crosses the state of Coahuila from N to S, with a series of parallel mountain ridges, which enclose fluvio-lacustrine intermontane flats of different extension. The Cuatro Cienegas plain is one of these flat areas. It extends over an area of about 840 km 2 and is located at 27° N and 102° W, at an altitude of about 700 metres. The high sloping walls of the Sierra Madera, which reach an altitude of 3020 m a.s.l., and the lower Sierra Menchaca, form the northern boundary of the area. The Sierra San Vincente and Sierra La Purisima border the plain on the eastern side. The southwestern boundary is the Sierra La Fragua, whereas the Sierra San Marcos y Pinos divides the Cuatro Cienegas plain into two parts in its southern part (Fig. 1). All these mountains consist mainly of Cretaceous limestone folded into long asymmetric anticlines. Their more steep slopes, usually the southwestern sides, often show vertical or overturned beds. Steep slopes and vertical walls are deeply cut by longitudinal and transverse streams, which together form a typical “trellis” pattern. The northeast-facing slopes, many of which correspond to International Journal of Speleology 36 (2) 83-92 Bologna (Italy) July 2007

Evaporite karst in Italy: a review

*jo.dewaele@unibo.it Citation:

Hydrodynamic and Geochemical Features of Metamorphic Carbonate Aquifers and Implications for Water Management: The Apuan Alps (NW Tuscany, Italy) Case Study

Carbonate rocks may be considered among the most important and strategic aquifers, given their widespread and the general high quality of groundwater flowing through them. Nevertheless, the karst systems developed within such aquifers promote conditions of high vulnerability to contamination and a high variability of groundwater flow rate, thus making the management of these water resources difficult. These critical features can be accentuated in metamorphosed carbonates, because of the massive structure of the rock that favours a low density of the karst network, and a preferential flow pattern throughout well-developed karst conduits. Furthermore, these rocks are often subject to quarrying and associated risk of pollution, mainly due to the fine slurry produced during marble cutting. This chapter presents the case of the Apuan Alps (NW Tuscany, Italy), where the main hydrogeological units are represented by metamorphosed dolostones and limestones (“Grezzoni” and marble, respectively), the latter being widely quarried to produce ornamental stones, as the famous Carrara marble. High-pressure ductile deformations and the consequent metamorphism have reduced the hydraulic conductivity of bedding surface, whereas the tectonic exhumation due to low-angle extensional faults has limited the development of diffuse fracture joints. For these reasons, an important subterranean storage of water is represented by epikarst porosity (unloading fissures and solution pockets) and vadose seepage, whereas in the epiphreatic and phreatic zones, the karst conduits have a high hydraulic conductivity but a low storage capability. Large flow rates and physical-chemical and isotopic variations, both in space and time, are observed at the springs as a consequence of differentiation of groundwater flow paths and hydrodynamic conditions. The main results derived from several years of study in the region are discussed in order to underline the high complexity of aquifer systems hosted in metamorphic carbonate rocks and to emphasize that multidisciplinary studies can provide knowledge useful for managing water resources in these very complex contexts.