Calcarenite

Coastal depositional environments are the site of complex interactions between continental and marine processes. Barrier islands are highly dynamic coastal systems, typical of these transitional environments, and are affected by sea level changes and the accumulation of transgressive deposits with the landwards migration of the coast. The offshore of Marzamemi (Syracuse Province, Sicily), in the south-eastern portion of the Hyblean foreland, represents an excellent site for the study of transgressive deposits and their connection with the sea-level changes. The available dataset consisted of new high-resolution bathymetry (Multibeam), whose description and interpretation through a Digital Elevation Model (DEM) was integrated with a grid of eighteen seismic profiles (SPARKER). In the investigated bathymetric range, from about −5 m to −60 m, a sensibly different morphological setting between the northern and southern sectors was evident. Within the whole study area, three bathymetric ...

Scicli and the other Baroque cities of the "Val di Noto" (Catania, Militello, Caltagirone, Palazzolo, Siracusa, Noto, Ragusa e Modica), were recently included in the World Heritage List. These cities were completely destroyed following the earthquake of 1693 and then were involved in an intense period of rebuilding and artistic flowering. In particular, Scicli was reconstructed with the almost exclusive use of a local calcarenite, which belongs to the Ragusa Formation. Due to its nature, this carbonate rock undergoes to many alteration and degradation forms (chromatic alteration, alveolization, differential disaggregation, efflorescence, decohesion, exfoliation and detachment). Therefore, different products (beeswax, vegetable oils, natural and synthetic resins) were used in the past with the aim to preserve the monuments from decay. In this study, through a diagnostic analysis, the degradation materials occurring in the churches of St. Matteo, St. Michele and Carmine in t...

The origin of a peculiar type of silicified limestone with nodular flints used in parish churches at Sluizen and Vreren, south of Tongeren (province of Limburg, Belgium), has now been elucidated by the discovery of the same rock type in its natural setting, namely the silicified top of the Cretaceous which underlies Clay-with-flints (‘flint eluvium’) and Oligocene sands in a disused quarry at Elst, municipality of Riemst (Limburg, Belgium). Co-operation between professional geologists and amateur palaeontologists has allowed to characterise this rock type, here referred to as ‘Elst tauw’, both petrographically and palaeontologically. The rich echinoid fauna has also been assessed, on the basis of a comparison with assemblages from the Clay-with-flints at Halembaye (Haccourt/Lixhe, province of Liège, Belgium) and at Zichen-Eben Emael in the Hesbaye region. P.J. Felder's ecozones, based on bioclast assemblages, substantiated by analyses of petrographical biofacies features of the ...

Petrophysical proprieties such as porosity, density, saturation have a marked impact on acoustic proprieties of rocks. Hence, there has been recently a strong incentive to use new geophysical techniques to invert such properties from seismic or sonic measurements for rocks characterization. The P-wave velocity, is non-destructive and easy method to apply in both field and laboratory conditions, has increasingly been conducted to determine the geotechnical properties of rock materials. The P-wave velocity of a rock is closely related to the intact rock properties and measuring the velocity in rock masses describes the rock structure and texture. The present work deals with the use of simple and non destructive technique, ultrasonic velocity to predict the porosity and density of calcarenite rocks that is characteristic in historical monument. The ultrasonic test is based on measuring the propagation time of a P-wave in the longitudinal direction. Good correlations between P-wave velo...

The city of Matera, as several other ancient historical town, is recovering a large part of its ancient parts developing a policy of urban regeneration. In the early 90s during the restoration works of the main square, Piazza Vittorio Veneto, it was re-discovered a huge underground space used as water reservoir named Palombaro Lungo. It was built linking ancient pre-existing smaller caves and completed at the end of the 19th century making it impermeable with opus signinum. The hypogeum is dug in a Plio-Pleistocene rock called Gravina Calcarenite. It is a weak rock with good mechanical properties, low permeability and easy to be dug. The internal geometry of the hypogeum and the rock thicknesses above the caves was reconstructed by the integration of topographic and GPR surveys. In this paper is presented a geo-mechanical model of Palombaro Lungo underground reservoir and an evaluation of its stability that is part of the studies for the evaluation for the recovery of the ancient hi...

The upper Campanian (Cretaceous) of the Hacımehmet area (south of the city of Trabzon; Eastern Pontides) is mainly composed of calciclastic turbidites. The basinal unit of the 119 m thick succession includes thin red pelagic limestone interlayers and conglomerates dominated by volcanic clasts. The overlying upper slope and lower slope units of the sequence consist of an alternation of allochthonous calcarenite/calcirudite beds and pelagic marls and mudstones. Calcarenite/calcirudite beds dominate the upper slope unit of the succession and are composed of transported material, including benthic foraminifers, red algae, bryozoan, crinoid and rudist fragments, inoceramid bivalve prisms and neritic and pelagic carbonate lithoclasts. The occurrence of Helicorbitoides boluensis (Sirel) extracted from the calcarenite/calcirudite beds indicates a Campanian age. Identifiable rudists such as Joufia reticulata Boehm, Bournonia cf. anatolica Ozer, Biradiolites cf. bulgaricus Pamouktchiev and ?B...

The history of the Earth is a story of the coevolution
of minerals and microbes: not only have numerous
rocks arisen from life but also life itself may have formed
from rocks. To understand the strong association between
microbes and inorganic substrates, we investigated the moonmilk,
a calcium carbonate deposit of possible microbial origin,
occurring in the Iron Age Etruscan necropolis of Tarquinia,
in Italy. These tombs provide a unique environment
where the hypogeal walls of the tombs are covered by this
speleothem. To study moonmilk formation, we investigated
the bacterial community in the rock in which the tombs were
carved: calcarenite and hybrid sandstone.We present the first
evidence that moonmilk precipitation is driven by microbes
within the rocks and not only on the rock surfaces. We also
describe how the moonmilk produced within the rocks contributes
to rock formation and evolution. The microbial communities
of the calcarenite and hybrid sandstone displayed,
at the phylum level, the same microbial pattern of the moonmilk
sampled from the walls of the hypogeal tombs, suggesting
that the moonmilk originates from the metabolism
of an endolytic bacterial community. The calcite moonmilk
is the only known carbonate speleothem on Earth with undoubted
biogenic origin, thus representing a robust and credible
biosignature of life. Its presence in the inner parts of
rocks adds to its characteristics as a biosignature.