General and specific growth marks in pegmatite beryls

Growth marks of pegmatite beryls can be divided into general and specific in relation to their types and distributions. Dislocation absence and growth bands have been recognized as general growth marks of the environment while minor element concentrations and optical anomalies as specific to the local growth medium.     

Amino acid racemization dating of quaternary deposits of central and Southern Italy

Results are discussed of amino acid racemization dating of numerous samples of bones, teeth, tooth enamel and fossil shells. Racemization dating proved to be a very useful tool to date non-marine and marine deposits which are a few hundred thousand years old, as well as to correlate and chronologically classify even more ancient marine deposits. Aspartic acid racemization was used to date samples aged less than 80,000–100,000 yr; for more ancient samples, isoleucine epimerization, instead, was resorted to.In this work, dates were established for some important fragments of human bones and of large-mammalian fauna weighing a few grams, which would have been impossible to date with the ¹⁴C technique, requiring a large amount of bone material.The extent of isoleucine epimerization was measured in Glycymeris genera to estimate the age of numerous marine deposits of the Tyrrhenian coast of Centra-Southern Italy and of Sardinia. In the Tarquinia area (Latium) three marine terraces were identified, which were estimated to be approx. 120,000, 200,000 and 350,000 yr old. In Sardinia, five marine horizons were identified; the youngest deposit (Neotyrrhenian) proved to be present at Punta tramontana and Santa Reparata, while, at Riola and Stagno di Sassu, the most ancient marine deposits of Sardinia were found. In the Rome area, the Monte Mario Formation was estimated to be coeval with Monte delle Piche Formation. Finally, from the terraced coastal deposits of Capo Milaazzo (Sicily), Panarea (Eolian archipelago), Archi (Calabria) and Gallipoli (Apulia), a Tyrrhenian age range of 100,000–120,000 yr was obtained.     

UNESCO World Heritage sites in Italy affected by geological problems, specifically landslide and flood hazard

A National Research Council, Research Institute for Hydrogeological Protection (IRPI) study on Italian monuments included in the UNESCO World Heritage List has revealed that many are affected by geological, geomorphological, and engineering geological problems. These monuments are static entities set in an environment that often manifests highly dynamic processes. As part of the efforts to protect sites of cultural and natural heritage, this study has applied a preliminary and empirical Geographical Information System-based method developed to characterize the environmental hazards at the sites where the monuments are located. Because the study of hydrogeological degradation falls within the province of IRPI, this hazard zoning focuses on river and mountain slope dynamics specifically concerning landslides and floods.     

Pressure–temperature evolution of the late Hercynian Calabria continental crust: compatibility with post‐collisional extensional tectonics

The late Hercynian tectonic evolution of the Calabria crust is characterized by peak metamorphic conditions up to 800 °C and 1000 MPa, and coeval mid‐crustal granitoid emplacement at 304–300 Ma. To check if a post‐collisional extensional framework, similar to that of other Hercynian massifs, can explain petrologic data, we model the pressure–temperature evolution of the crust during extension following granitoid emplacement. Model parameters are constrained by petrologic, geochemical and structural data. Computed P–T paths are characterized by nearly isothermal decompression followed by isobaric cooling, which show a good fit to petrologic P–T paths for duration of extension between 5 and 10 Ma. The model results, therefore, support an interpretation of the magmatic and metamorphic evolution of the Calabria crust in terms of the late Hercynian extension. In this framework, slab break‐off is a reasonable explanation for the common evolution of the southern European Hercynian massifs.     

Paleontological evidence on the Earth's rotational history since early precambrian

The daily growth layers arranged into seasonal and tidal patterns, present in calcified structures of many modern as well as fossil organisms, provide evidence on the length of lunar month and year in the geological past.The data presented are mainly from molluscan shells and indicate that the number of days per lunar month and per year has decreased significantly since Ordovician time. The change possibly has not taken place at a uniform rate.Banding and periodical patterns in stromatolites reflect cycles of daily, tidal, and seasonal nature, but rarely, if ever, represent a complete growth record. Such lack of completeness is a function of many parameters like water depth, energy of the environment, biological and physical disruptions, which are not always determinable in fossils. Phanerozoic stromatolites show a higher degree of incompleteness than precambrian ones. Figures obtained from stromatolites counts cannot be compared to those from molluscs. Preliminary data indicate that the length of the synodic month during Gunflint time (1750 m.y. ago) was between 36 and 39 days. The oldest known stromatolites ( 2800 m.y.) show patterns that are interpreted as due to tidal influence and have a periodicity of 10, 20 and 40 laminae. The obvious conclusions are that the Moon has been associated with Earth since at least Early Precambrian times, that all theories implying a late capture of the Moon should be revised and that the calculated secular changes in the Earth's rotation rate cannot be accepted as representative for the all geological history.Paper presented at the AAAS Symposium on the Early History of the Earth and Moon in Philadelphia on 28 December 1971.     

Sulphuric acid geofluid contribution on thermal carbonate coastal springs (Italy)

Hypogenic caves, developed by sulphuric acid speleogenesis, are known all over the world among which the Santa Cesarea Terme caves have been included. They are four submerged caves, located along a coastal carbonate sector in Southern Italy and hosting the outflow of coastal springs of thermal mixed waters (from 21 to 33 °C). These waters derive from the mixing of three water end members: the fresh pure groundwater of a wide karstic aquifer, the deep sulphur thermal water and the seawater. This cave system represents an almost unique case of hypogenic sea caves in carbonate environment. The thermal mixed waters have a different effect on the surrounding rocks of the caves, influencing the sulphuric acid speleogenetic process within the whole cave system. To understand the complex and overlapping natural processes acting on the development of these coastal caves, a multidisciplinary study has been carried out. This study has integrated all the data resulting from different methods and technologies, merging morphology, structural geology, hydrogeology, hydrogeochemistry and mineralogy. This multidisciplinary study has allowed to define the main geochemical processes acting within these caves, including the cave development and the formation of the mineral concretions. After the introduction of H₂S in the thermal waters, formed by the reduction of sulphates in the sedimentary deposits crossed at depth in the offshore, the oxidation occurs within the caves, producing sulphuric acid. Favoured by upwelling deep-seated thermal flows, this acid dissolves the limestone, with condensation corrosion process that involve replacement of limestone rock with gypsum. This process has resulted to be more active and remarkable within the Gattulla Cave, one of the Santa Cesarea Terme sea caves.     

Hydrogeological and multi-isotopic approach to define nitrate pollution and denitrification processes in a coastal aquifer (Sardinia,Italy)

Agricultural coastal areas are frequently affected by the superimposition of various processes, with a combination of anthropogenic and natural sources, which degrade groundwater quality. In the coastal multi-aquifer system of Arborea (Italy)—a reclaimed morass area identified as a nitrate vulnerable zone, according to Nitrate Directive 91/676/EEC—intensive agricultural and livestock activities contribute to substantial nitrate contamination. For this reason, the area can be considered a bench test for tuning an appropriate methodology aiming to trace the nitrate contamination in different conditions. An approach combining environmental isotopes, water quality and hydrogeological indicators was therefore used to understand the origins and attenuation mechanisms of nitrate pollution and to define the relationship between contaminant and groundwater flow dynamics through the multi-aquifer characterized by sandy (SHU), alluvial (AHU), and volcanic hydrogeological (VHU) units. Various groundwater chemical pathways were consistent with both different nitrogen sources and groundwater dynamics. Isotope composition suggests a mixed source for nitrate (organic and synthetic fertilizer), especially for the AHU and SHU groundwater. Moreover, marked heterotrophic denitrification and sulfate reduction processes were detected; although, for the contamination related to synthetic fertilizer, the attenuation was inefficient at removing NO₃^? to less than the human consumption threshold of 50 mg/L. Various factors contributed to control the distribution of the redox processes, such as the availability of carbon sources (organic fertilizer and the presence of lagoon-deposited aquitards), well depth, and groundwater flow paths. The characterization of these processes supports water-resource management plans, future actions, and regulations, particularly in nitrate vulnerable zones.     

Climate Change-Induced Changes in the Chemistry of a High-Altitude Mountain Lake in the Central Alps

Aquatic Geochemistry - Mountains are among the most sensitive ecosystems to climate change, and one of the most evident signs of climate-related effect is the continuous net loss of ice from the...     

Coping with uncertainties through an automated workflow for 3D reservoir modelling of carbonate reservoirs

Reliable 3D modelling of underground hydrocarbon reservoirs is a challenging task due to the complexity of the underground geological formations and to the availability of different types of data that are typically affected by uncertainties.In the case of geologically complex depositional environments,such as fractured hydrocarbon reservoirs,the uncertainties involved in the modelling process demand accurate analysis and quantification in order to provide a reliable confidence range of volumetric estimations.In the present work,we used a 3D model of a fractured carbonate reservoir and populated it with different lithological and petrophysical properties.The available dataset also included a discrete fracture network(DFN)property that was used to model the fracture distribution.Uncertainties affecting lithological facies,their geometry and absolute positions(related to the fault system),fracture distribution and petrophysical properties were accounted for.We included all different types of uncertainties in an automated approach using tools available in today's modelling software packages and combining all the uncertain input parameters in a series of statistically representative geological realizations.In particular,we defined a specific workflow for the definition of the absolute permeability according to an equivalent,single porosity approach,taking into account the contribution of both the matrix and the fracture system.The results of the analyses were transferred into a 3D numerical fluid-dynamic simulator to evaluate the propagation of the uncertainties associated to the input data down to the final results,and to assess the dynamic response of the reservoir following a selected development plan.The"integrated approach"presented in this paper can be useful for all technicians involved in the construction and validation of 3D numerical models of hydrocarbon-bearing reservoirs and can potentially become part of the educational training for young geo-scientists and engineers,since an integrated and well-constructed workflow is the backbone of any reservoir study.