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We present new data on the 4.2 ka event in the central Mediterranean from Corchia Cave (Tuscany, central Italy) stalagmite CC27. The stalagmite was analyzed for stable isotopes (δ13C and δ18O) and trace elements (Mg, U, P, Y), with all proxies showing a coherent phase of reduced cave recharge between ca. 4.5 and 4.1 ka BP. Based on the current climatological data on cyclogenesis, the reduction in cave recharge is considered to be associated with the weakening of the cyclone center located in the Gulf of Genoa in response to reduced advection of air masses from the Atlantic during winter. These conditions, which closely resemble a positive North Atlantic Oscillation (NAO) type of configuration, are associated with cooler and wetter summers with reduced sea warming, which reduced the western Mediterranean evaporation during autumn–early winter, further reducing precipitation. [ABSTRACT FROM AUTHOR]

The results of a Ground-penetrating radar (GPR) survey were compared with the archaeological excavation outcomes of a twelfth century abbey site (Badia Pozzeveri). The goal was to associate the types of reflections recorded in GPR profiles and high-amplitude features visible in amplitude maps with unearthed archaeological features. GPR profiles crossing the walls evidenced axes of hyperbolic point source reflections and short planar reflections respectively generated by the stones forming the lateral sides/upper corners and the top of the structure. Moreover, the stones in the core of the wall caused small hyperbolic point source reflections with interfering axes, which produced a chaotic reflection profile. The resampling and gridding of these reflections collectively generated high-amplitude linear features in the amplitude maps. The presence in the graves of bones generates small hyperbolic point source reflections with interfering axes in the GPR profile, with a consequently chaotic reflection profile. Moreover, the existence of lythic slabs topping and/or siding the graves generates short planar reflections and axes of hyperbolic point source reflections. The resampling and gridding of these types of reflections generates in the amplitude map features that cannot be locally distinguished from those caused by the local aggregation of sediments with no archaeological relevance. The GPR profiles crossing trenches and pit-kiln showed dipping reflectors unconformably resting on a basal planar reflector. Disconformity marks the onset of trench and pit-kiln decommissioning with the infilling of clayey silty layers and anthropogenic remains. These features in the amplitude maps correspond to medium to high-amplitude areas. The results show that types of reflection can be associated to specific elements of archaeological structure for a detailed interpretation of a complex subsurface setting. Furthermore, it is evidenced that the interpretation of GPR profiles must be considered an indispensable pre-requisite for a full comprehension of amplitude maps. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Veins are the geologic record of fluids that filled fractures at depth in the crust. In southern Tuscany (Italy), well-exposed Oligocene–Early Miocene sandstones hosting vein systems provide insight into the role of pore fluid and the stress state at the time of vein formation. The stress ratio (Φ =(σ 2 − σ 3)/(σ 1 − σ 3)) and driving stress ratio (R′=(P f − σ 3)/(σ 1 − σ 3)) were determined by analysing the distribution, length and aperture of fractures and veins and the magnitude of fluid overpressure. The derived fluid overpressure for the whole vein system ranges from 30MPa to 64MPa, with an average of 43MPa; these values indicate that veins formed under supra-hydrostatic pressure conditions. Despite their spatial contiguity, two different vein arrays show very different stress and driving pressure ratios. One vein system is characterised by Φ =0.62 and R′=0.60, the other by Φ =0.54 and R′=0.78. The described vein systems are an example of a close spatial association of two non-hydraulically connected vein systems representing fluids focused through the upper crust. [Copyright &y& Elsevier]

The current rapid change of the Earth's climate has resulted in an increasing interest for the past warm periods as potential long-term scenarios of the effects of the present global warming. The last such a period occurred 129–116 ka, known as the Last Interglacial (LIG), when the continental ice volume was significantly smaller than present, leading to a global sea-level (GSL) higher than present one. Detailed morpho-stratigraphic data, supported by a robust U/Th chronology, from Grotta delle Capre, central Italy, provided new chronological insights on the relative sea-level (RSL) dynamic during the LIG in the Mediterranean region. Our results indicate that, on Tyrrhenian Sea coasts of the central Italy, after having stationed at ∼9 m a.s.l., the LIG RSL fell at an elevation <3 m a.s.l. as early as before 123 ka, and then no longer rose above this elevation either during the later stages of the LIG or afterwards. The results match previous studies based on U/Th dating of terrestrial limiting points from Grotta Infreschi, ∼200 km SE from Grotta delle Capre along the same Tyrrhenian Sea coasts, and are in agreement with the Red Sea RLS and GSL records and the probabilistic LIG sea level assessments based on globally distributed records. On the other hand, our reconstruction is not supported by implications of U/Th dating of corals and phreatic overgrowth on speleothems from the Balearic Island of Mallorca. Such an inconsistency in the overall knowledge around the LIG RSL reconstruction results in a high uncertainty in modelling the ice and sea-level dynamic during this warm period, which needs to be reduced through more and more high-resolution, stratigraphic and chronological investigations of the morphological and sedimentary sea-level records. • The maximum RLS elevation during the LIG at Grotta delle Capre was likely at 9 m a.s.l. • Before 123 ka the RSL at Grotta delle Capre fell from c. 9 m to below 3 m a.s.l. • The local RLS record is either in agreement or disagreement with regional-global data. • More chronologically well-constrained RLS records are needed to reduce uncertainties. [ABSTRACT FROM AUTHOR]

The trace-element geochemistry of speleothems is becoming increasingly used for reconstructing palaeoclimate, with a particular emphasis on elements whose concentrations vary according to hydrological conditions at the cave site (e.g. Mg, Sr, Ba and U). An important step in interpreting trace-element abundances is understanding the underlying processes of their incorporation. This includes quantifying the fractionation between the solution and speleothem carbonate via partition coefficients (where the partitioning (D) of element X (D X) is the molar ratio [X/Ca] in the calcite divided by the molar ratio [X/Ca] in the parent water) and evaluating the degree of spatial variability across time-constant speleothem layers. Previous studies of how these elements are incorporated into speleothems have focused primarily on stalagmites and their source waters in natural cave settings, or have used synthetic solutions under cave-analogue laboratory conditions to produce similar dripstones. However, dripstones are not the only speleothem types capable of yielding useful palaeoclimate information. In this study, we investigate the incorporation of Mg, Sr, Ba and U into a subaqueous calcite speleothem (CD3) growing in a natural cave pool in Italy. Pool-water measurements extending back 15 years reveal a remarkably stable geochemical environment owing to the deep cave setting, enabling the calculation of precise solution [X/Ca]. We determine the trace element variability of 'modern' subaqueous calcite from a drill core taken through CD3 to derive D Mg , D Sr , D Ba and D U then compare these with published cave, cave-analogue and seawater-analogue studies. The D Mg for CD3 is anomalously high (0.042 ± 0.002) compared to previous estimates at similar temperatures (∼8 °C). The D Sr (0.100 ± 0.007) is similar to previously reported values, but data from this study as well as those from Tremaine and Froelich (2013) and Day and Henderson (2013) suggest that [Na/Sr] might play an important role in Sr incorporation through the potential for Na to outcompete Sr for calcite non-lattice sites. D Ba in CD3 (0.086 ± 0.008) is similar to values derived by Day and Henderson (2013) under cave-analogue conditions, whilst D U (0.013 ± 0.002) is almost an order of magnitude lower, possibly due to the unusually slow speleothem growth rates (<1 μm a−1), which could expose the crystal surfaces to leaching of uranyl carbonate. Finally, laser-ablation ICP-MS analysis of the upper 7 μm of CD3, regarded as 'modern' for the purposes of this study, reveals considerable heterogeneity, particularly for Sr, Ba and U, which is potentially indicative of compositional zoning. This reinforces the need to conduct 2D mapping and/or multiple laser passes to capture the range of time-equivalent elemental variations prior to palaeoclimate interpretation. [ABSTRACT FROM AUTHOR]

After eight decades since its discovery in 1939, new investigations have been undertaken at Grotta Guattari (Latium, central Italy), a coastal cave by the Tyrrhenian Sea coast and one of the iconic sites of the Italian prehistory, as it yielded an almost complete skull and other remains of Neanderthals. The new excavations of the innermost and untouched cave deposits resulted in an outstanding amount of mammal bones, 40 out of which attributable to Neanderthal, including new large portions of cranial remains. Preliminary taphonomic hints and the collected stratigraphic evidence strongly indicate that the impressive accumulation of the large mammal bones was the work of spotted hyena, in a period in which human frequentation was really sporadic or even completely absent. The new acquired U/Th chronology of Grotta Guattari speleothems provided new constraints for reconstructing the sedimentary and paleoenvironmental history of the archaeological successions and human remains. The accumulation of terrestrial sediments started at ∼112 ka, immediately after the end of the Last Interglacial sea-level highstand (∼116 ka). However, the hyena frequentation, and thus the bone accumulations, occurred several thousands of years after and lasted for a very short time interval, precisely between slightly before 66 ka and 65 ka. The cave became abandoned by hyena after ∼65 ka and before ∼59 ka, because of the cave obstruction and/or the altered environmental conditions related to the Heinrich Event 6 (∼64–60 ka). The regional paleoclimatic records indicate severe conditions during the short interval of the hyena frequentation. In contrast, though providing evidence of open and arid environments, the faunal assemblage and the pollen from Grotta Guattari reveal that the local conditions were less severe, likely because of the mitigating effect of the Tyrrhenian Sea. In the framework of the Italian findings, Grotta Guattari results the richest and better chronologically constrained site of Neanderthal remains, posing it as one of the rare sites of the European prehistory that allows putting into the context an extraordinary large sample of the population of Neanderthals, and of other large mammals, in a very narrow and precisely dated temporal interval of the early Pleniglacial. • Hyena accumulated mammal bones, including Neanderthal, in Guattari Cave. • U/Th chronology dates the hyena occupation during the brief interval of 66–65 ka. • The glacial conditions at 66–65 ka were locally mitigated by the proximity of the sea. • Guattari arises as the richest and better dated Italian site of Neanderthal remains. [ABSTRACT FROM AUTHOR]

Speleothems are potentially excellent archives of the Earth's magnetic field, capable of recording its past variations. Their characteristics, such as the continuity of the record, the possibility to be easily dated, the almost instantaneous remanence acquisition and the high time-resolution make them potentially unique high-quality Paleosecular Variation (PSV) recorders. Nevertheless, speleothems are commonly characterized by low magnetic intensities, which often limits their resolution. Here we present a paleomagnetic study performed on two cores from a flowstone from the Rio Martino Cave (Western Alps, Italy). U/Th dating indicates that the flowstone's deposition covers almost the entire Holocene, spanning the period ca. 0.5–9.0 ka, while an estimation of its mean growth rate is around 1 mm per 15 years. The flowstone is composed of columnar calcite, characterized by a highly magnetic detrital content from meta-ophiolites in the cave's catchment. This favorable geological context results in an intense magnetic signal that permits the preparation and measurement of thin (∼3 mm depth equivalent) samples, each representing around 45 yr. The Characteristic Remanent Magnetization (ChRM), isolated after systematic stepwise Alternating Field demagnetization, is well defined, with Maximum Angular Deviation (MAD) generally lower than 10°. Paleomagnetic directional data allow the reconstruction of the PSV path during the Holocene for the area. Comparison of the new data with archeomagnetic data from Italian archeological and volcanic records and using the predictions of the SHA.DIF.14k and pfm9k.1a global geomagnetic field models shows that the Rio Martino flowstone represents an excellent recorder of the Earth's magnetic field during the last 9,000 years. Our high resolution paleomagnetic record, anchored by a high-quality chronology, provides promising data both for the detection of short term geomagnetic field variations and for complementing existing regional PSV curves for the prehistoric period, for which well-dated data are still scarce. [ABSTRACT FROM AUTHOR]

Abstract: High resolution, LIDAR-derived digital elevation models of volcanic areas can significantly improve knowledge of lava flow morphology and emplacement mechanisms. Here we focus on single flow units, presenting a new semi-automatic procedure which provides a quantitative analysis of their shape. The method relies on the automatic processing of the elevation profiles obtained on transects orthogonal to the flow unit axis. The initial phase of the Mount Etna flank eruption from September 2004 is taken as test case, and the procedure is applied on an active lava flow, which was emplaced on the eastern flank of the volcano. The main topographic dataset used is a 2-m-resolution digital elevation model obtained from a LIDAR survey. Starting from the axis of a lava flow unit, our method yields morphometric data on the flow unit at a 2m spacing, calculating parameters including flow width, channel width, the heights of the levees, inward and outward slope of levees, and estimating pre-emplacement slope along the axis. The procedure is embedded in a customized GIS, which allows easy processing, handling and displaying of data. The procedure has also been applied to another flow unit emplaced during the October–November 1999 overflow from the Bocca Nuova crater. Results show that the channel width seems to accommodate first‐order trends of the pre-emplacement slope along the flow unit axis, while it is little affected by high frequency changes in slope; in contrast, flow unit width and flow unit thickness are apparently influenced by small‐scale changes in slope. The different emplacement conditions of the two flow units are reflected by the overall contrasting morphologies, as shown by the different average thickness and by the different ratios between (i) flow width vs. channel width and (ii) flow unit section area vs. channel width. The new method provides an enhanced, systematic and thorough morphometric description of flow units, which may improve the understanding of the emplacement mechanisms of lava flows on Earth and other planets. [Copyright &y& Elsevier]

The Upper Oligocene Macigno Formation cropping out in the coastal section of SW Tuscany represents the sedimentary fill of a foredeep basin developed during the collisional stages that led to the construction of the Apennine mountain belt of peninsular Italy. The stratigraphic sequence consists of alternating sandstones and siltstones, that are affected by km-scale contractional structures, namely SW-dipping thrusts and related NE-verging folds. An original field survey carried out along a superb coastal exposure, integrated with analysis of mesoscopic fabrics and their overprinting relationships, makes it possible to unravel a complex deformation history. Four main deformation stages are recognized: i) layer-parallel shortening A; ii) top-to-the-foreland shear B; iii) folding C, comprising the fold nucleation sub-stage C1 and the fold amplification sub-stage C2; and iv) thrust propagation D. The sequence of recognized stages indicates a progressive deformation history of the Macigno Formation as it was incorporated within the evolving Apennine orogenic system. The kinematic history inferred from deformation fabrics and their overprinting relationships within Macigno Fm. deposits in SW Tuscany shows remarkable analogies with the structural evolution of foredeep sediments from other fold-and-thrust belts, yet with little deviations mainly consisting of pureshear vs. simple shear fluctuations in the early history of accretion. These provide original information on the modes of accretion of foredeep deposits within evolving collisional belts, thus contributing to an enhanced understanding of orogenic dynamics during mountain building with a classical example whose evolution is unravelled in detail. • Syn-orogenic deposits of the Oligocene Macigno Fm. crop out in southern Tuscany. • Minor structures were investigated along well exposed coastal exposures. • Overprinting relationships of minor fabrics outline a progressive deformation history. • The inferred history records accretion of the Macigno Fm. within the Apennine wedge. [ABSTRACT FROM AUTHOR]