Travertines from Tivoli area (Central Italy) possess abundant shrub-like fabrics that are laterally continuous over hundreds of square meters. They occur dominantly in horizontal layers with ...aggradational and progradational stacking patterns. Their fabrics and morphologies are remarkably similar to the shrubs lithotypes reported in literature for the Pre-Salt reservoirs, offshore Brazil and Angola, with huge oil accumulations. Petrographic and micro-computer tomography analyses allowed the identification of six shrub morpho-types (i.e., narrow dendriform, wide dendriform, fili dendriform, arborescent, arbustiform and pustular). Dendriform shrubs are the most common lithotype in Tivoli area, and three different subtypes could be distinguished according to the arrangement of their branches. The shrubs consist largely of peloidal micritic aggregates engulfed in spar calcite, ranging in average from 1 to 3cm in height. The shrubs are interpreted to have developed in very shallow extensive waterlogged slightly inclined flat areas, changing laterally into a slope system with crusts as the main lithotype. Changes in the hydrodynamic conditions with episodes of stagnancy influenced the shrub morpho-types making them very variegated.
Shrub morphologies likely reflect specific (micro-) environments that are controlled by water flow rates, evaporation and microbial activity. The latter processes influenced shrub fabric and morphology. Under high flow conditions, CO2 degassing is the main process leading to carbonate precipitation. Consequently, denser and tightly packed morphologies will precipitate, composing mainly the crust lithotype. In this scenario microbes are less dominant. Dendriform shrubs, with narrow, wide and fili morphologies are interpreted to occur in moderate to low energy water flows. Narrow dendriform shrubs reflect faster flowing conditions, with decreasing impact of flow on the morphological aspects from wide dendriform shrubs to fili dendriform shrubs. Slow to very slow flowing waters are more characteristic for the arborescent, arbustiform and pustular shrubs that possibly are highly influenced by evaporation. A decrease of water flow likely allows higher microbial activity, and consequently, shrub morphologies become more fragile and enriched in peloidal micritic aggregate fabrics.
•Shrub morpho-types characterization from Tivoli travertines;•Lithologs correlation in Tivoli area;•Paleoenvironmental reconstruction for Tivoli shrub morpho-types;•Impact of flow water conditions in the precipitation of shrub morpho-types;•Correlation between water flow rates and microbial influence in the mineral precipitation.
The terrestrial limestones forming at the emergence of thermal springs show a variety of unusual depositional facies. The specific lithological and petrological features of these deposits have few ...counterparts in the marine, and continental, karst‐related carbonates, but they are typical of the epigean limestone that has been quarried since antiquity in the surroundings of Tivoli (Rome) under the name of travertine, where it is still forming in hydro‐geothermal fields linked to extensional tectonics. The physicochemical, hydrodynamic and geological conditions specific to the Tivoli thermal spring system imply hypersaturated alkaline–sulphate, warm to hot waters, upwelling from springs fed through open fractures/faults in extensional and/or volcanic regimes. These features, together with the hydrodynamic behaviour of the water flows running from the vents, control the petrogenetic features of the travertine, a well‐bedded, mostly finely laminated, porous but quite compact limestone. The results of a detailed comparative petrological analysis carried out on the lithofacies of travertine limestones, and of those observed during formation within numerous active thermal spring fields, provide the elements required for an exhaustive textural classification of the travertine lithofacies, which has not yet been described systematically. According to the genetic processes and fabrics, the thermal deposits that originate from such hypersaturated alkaline–sulphate, warm to hot waters, can be subdivided into: abiotic crystalline crusts, microbially mediated crusts (microbialites) and granular deposits mostly represented by small accumulations of lime‐mudstone. Some of the granular deposits and the microbialites are only partially comparable with analogous sediments forming on tidal flats/sabkhas or other continental sites; however, the facies association of crystalline crusts and laminar curled microbialites has no counterpart in the marine realm. The widespread presence of thermophile bacteria and sulphobacteria, and the general absence of autochthonous eukaryote organisms, unable to live in poisonous sulphate waters, are also undeniable evidence of their thermal origin.
Объектом исследования стала «Статуя полководца из Тиволи», датируемая большинством исследователей второй четвертью I в. до н.э. Наш интерес к ней обусловлен тем, что до сих пор не было установлено — ...кого из лидеров Республики она возвеличила. Полагаем, что это Гай Марий. При этом учитываем, в частности, сходство лица «полководца из Тиволи» и лиц бюстов из Глиптотеки Мюнхена и Музеев Ватикана, в которых исследователи видят изображения именно этого военного и политического деятеля. Высекли же статую после смерти диктатора Л. Корнелия Суллы, а точнее — в период Первого триумвирата и, скорее всего, по инициативе Г. Юлия Цезаря. Это обстоятельство и определило её дальнейшую судьбу: статуя была сохранена. Она украшала храм Геркулеса Виктора, возведённого в Тиволи в I в. до н.э., при раскопках которого и была найдена.
The object of the study was the “Statue of the commander from Tivoli”, which dates back, according to the majority of researches, to the second quarter of the 1st century BCE. Our interest in it is due to the fact that it is still not known which of the leaders of the Republic was glorified in this way. We believe that it is about Gaius Marius that we should speak. We are also taking into account the fact that the “commander’s” face is rather similar to those of the busts from the Münchener Glyptothek and the Musei Vaticani, in which many scholars tend to recognize the military and political leader mentioned above. The sculpture was made after the death of the dictator L. Cornelius Sulla, or, more precisely, it was carved during the First Triumvirate, and most likely on the initiative of G. Julius Caesar. This circumstance determined its future fate: the statue survived. It was supposed to adorn the Templeof Hercules Victor, erected in Tivoli in the 1stcentury BCE, and it was during the excavations of the temple that the statue was found.
Sr and Nd isotopic ratios along with (REE + Y) and other trace elements were measured in bedded travertines from three quarries at Tivoli Terme, Latium, aimed at deciphering their chemical and ...isotopic characteristics for the origin and evolution of fluids. Travertines, which were deposited between ∼81 and ∼54 ka BP, display high Sr and low REY contents along with REYPAAS patterns, supporting their fluid origin mainly from marine rocks, in particular the Upper Triassic Burano Evaporite Fm. This has been confirmed by the narrow ranges of δ87Sr and εNd values, close to those of that formation and other Mesozoic marine carbonates from central Italy. A sample of today's thermal water from Tivoli Terme provided a REYPAAS pattern and a δ87Sr value comparable with travertines, both features supporting that today's water is analog to past hydrothermal fluids. The overlap of the chemical and Sr–Nd isotopic compositions of coeval travertines and thermal waters from Tivoli and Acquasanta Terme, Marche, suggests a common fluid origin, ruling out any significant contribution from magmatic fluids/rocks to Tivoli travertines, yet deposited at the periphery of the Alban Hills volcano. Lastly, the geochemical results provide implications for regional neotectonics and the role of CO2-rich fluid pressure in fault activation, even in mildly active to almost inactive tectonic domains.
•Past hydrothermal fluids had geochemical characteristics akin to today's thermal waters.•REYPAAS patterns and Sr–Nd isotopes support Triassic evaporites as the main fluid source.•Alban volcanism provided no significant geochemical contribution to hydrothermal fluids.•Fluids displayed rather steady geochemical characteristics between ∼81 and 54 ka BP.•Geochemical characteristics of Tivoli and Acquasanta travertines suggest similar fluid sources.
Morphologically-different deposits of thermal travertines are known worldwide, but what factors controlled their morphology, volume, and growth for tens of thousands of years is only partially ...understood. Two main morphotypes of Quaternary thermal travertines are reconsidered here to understand the reasons for their differential growth: the fissure ridge travertines of Denizli Basin, western Turkey, and the travertine plateau of Tivoli, central Italy. For comparable longevities and average vertical deposition rates, the main differences between the studied travertines are as follows: (1) volume of the travertine plateau is about one hundred times larger than each fissure ridge; (2) despite a larger volume, the travertine plateau does not produce relief, whereas the fissure ridges produce a characteristic prominent topography; (3) the travertine plateau grew primarily through lateral progradation, whereas the fissure ridges through vertical aggradation; (4) travertine deposition occurred in different environments: principally low-energy flat or shallow environments at Tivoli and high-energy inclined environments at Denizli; (5) the growth of the Tivoli plateau occurred in a subsiding basin, whereas the fissure ridges were not influenced by significant subsidence; (6) C- and O-isotope signatures from the two studied travertines are different; (7) despite similar annual precipitations, the present water discharge in the Tivoli area is about ten times greater than that of the Denizli Basin. U-series ages from the two deposits are correlated with paleoclimate oscillations at regional and global scales. Geological field evidence together with paleoclimate correlations suggest that, in both the study cases, the main body of travertine deposits (the bedded travertine) grew preferentially when the water table was high (warm and/or humid periods). Conversely, when the water table was depressed (cold and/or dry periods), the Tivoli travertine underwent partial erosion and the Denizli ridges were cut by axial veins and lateral sill-like structures filled by banded sparitic travertine. A comparative model is proposed where the main factor driving the difference in the morphostratigraphic architecture of fissure ridges and travertine plateaus is the volume of water discharge. A high discharge rate resulted in the precipitation of CaCO3 far away from the springs, hence driving the lateral progradation of the Tivoli plateau. A reduced discharge rate caused travertine precipitation close to the springs, thus causing the vertical aggradation of the Denizli fissure ridges. Paleoclimate oscillations must have controlled the amount of fluid discharge, which, in turn, must have influenced the opening of the feeding fractures by an increased pore pressure.
3D modelling represents a powerful tool to characterize the geobody architecture of depositional systems. Several examples have been proposed in literature both for marine carbonates and ...siliciclastics rocks. For modelling, quantitative data related to orientation, shape and dimension are fundamental. Continental carbonates, however, are not considered yet, likely because they cover a large range of deposits such as speleothems, tufas, lacustrine carbonates and travertines. The interpretation of the depositional environments of the latter is still in fact debated by the scientific community. However, the interest in continental carbonates and especially travertines increased over the last decades due to the discovery of supergiant unconventional reservoirs in the Southern Atlantic (i.e. the so-called “Pre-salt play”).
Aim of this paper is to present an innovative workflow to investigate and describe continental carbonates as geobodies based on a hierarchical approach applied to three large scale travertine settings, i.e. Terme di San Giovanni (Italy), Pamukkale (Turkey) and the Lapis Tiburtinus travertines (Italy). Travertine depo-systems are divided in three different depo-zones, namely proximal, intermediate and distal, that are characterized by different depo-elements, depo-shapes and depo-facies.
Finally, a 3D morphological model is created based on numerical and vector approaches and interpolation of both. The model can be applied to seismic data of Brazilian and Angolan Pre-salt, highlighting the similarities between these systems and for the first time the scale independence of these depositional system, representing an important advantage in their interpretation. The 3D model and the approach proposed facilitates seismic interpretation, allowing to define and characterize geometries of inaccessible geological contexts.
•Travertines can be used as analogue of some Pre-salt Cretaceous rocks.•Travertine outcrops provide fundamental quantitative data suitable to better understand inaccessible reservoirs as the Pre-salt.•Geometries of travertine depositional systems are similar to some of seismic reflectors encountered in Pre-salt.•Travertine depositional systems can be schematized in 3D models.
This work presents a sinkhole susceptibility and risk assessment mapping in Guidonia-Bagni di Tivoli plain (Italy), a travertine sinkhole-prone area where sudden occurrences of sinkholes have ...happened in past and recent times. We collected a point-like sinkhole inventory and we considered a series of different sinkhole-controlling and precursory factors over the study area, related to its geo-litho-hydrological setting and to its terrain deformational scenario, i.e. ground motion rates derived from InSAR COSMO-SkyMed imagery. A sinkhole susceptibility map was produced through a machine learning model, namely Maximum Entropy algorithm (MaxEnt). Results highlight that the most determining factors for sinkhole formation are the lithology, the travertine thickness, groundwater and the land use. The sinkhole susceptibility map was then combined with data on vulnerability and elements-at-risk economic exposure in order to provide a sinkhole risk map of the area. The outcomes show that areas at higher risk covers about 2% of the total study area and primarily relies on the zoning of the main urban fabric. In particular, it is worth to highlight that 5% of the whole road-network pavement and 27% of all the residential buildings fall into High and Very High risk classes. Overall, results of this work demonstrate capabilities of machine learning models to assess sinkhole susceptibility for predicting potential sinkhole areas, and provide a sinkhole risk map, along with information on urban environment, as a useful tool for urban planning and geohazard risk management.
This article reviews some of the digital tools currently available for reconstructive textual editing. First the main idea of reconstructive textual editing is summarised, then its steps amenable to ...algorithmic description are compared to similar ones in evolutionary biology. The the unequal ability of its variants to be relationship revealing is an important difference between the two fields. Two Latin texts with a complicated transmission are then introduced and used as data to illustrate some available tools in praxi. The main focus is on stemma reconstruction. Some steps of the process can already be largely automated, especially collating texts. On the whole it is found that tree-constructing software is of little help in the case of the medical text Liber Aurelii, whereas it is somewhat more helpful for Plato of Tivoli’s translation of the Centiloquium. In a concluding part, the main problems for algorithmic approaches to the stemma are discussed: incomplete witnesses leading to only partly overlapping text samples, contamination in some witnesses, and rooting the automatically generated trees.
