Professor Silvia Frisia

Dolomite [CaMg(CO3)2] formation under Earth surface conditions is considered largely inhibited, yet protodolomite (with a composition similar to dolomite but lacking cation ordering), and in some cases also dolomite, was documented in modern shallow marine and lacustrine, evaporative environments. Authigenic carbonate mud from Lake Neusiedl, a shallow, episodically evaporative lake in Austria consists mainly of Mg-calcite with zoning of Mg-rich and Mg-poor regions in µm-sized crystals. Within the Mg-rich regions, high-resolution transmission electron microscopy revealed < 5-nm-sized domains with dolomitic ordering, i.e., alternating lattice planes of Ca and Mg, in coherent orientation with the surrounding protodolomite. The calcite with less abundant Mg does not show such domains but is characterized by pitted surfaces and voids as a sign of dissolution. These observations suggest that protodolomite may overgrow Mg-calcite as a result of the changing chemistry of the lake water. During this process, oscillating concentrations (in particular of Mg and Ca) at the recrystallization front may have induced dissolution of Mg-calcite and growth of nanoscale domains of dolomite, which subsequently became incorporated as ordered domains in coherent orientation within less ordered regions. It is suggested that this crystallization pathway is capable of overcoming, at least at the nanoscale, the kinetic barrier to dolomite formation.

Modern to Holocene tropical Pacific stalagmites are commonly difficult to date with the U-series, the most commonly used dating method for speleothems. When U-series does not provide robust age models, due to multiple sources of 230Th or little U, radiocarbon is, potentially, the best alternative. The 14C content of two stalagmites (Pu17 and Nu16) collected from Pouatea and Nurau caves in the Cook Island Archipelago of the South Pacific were measured to obtain accurate chronology for their most modern parts. The bomb-pulse soil continuum modelling indicates that bomb radiocarbon in Pu17 onsets in 1956 and reaches its maximum in 1966 CE, suggesting a fast transfer of atmospheric carbon to the stalagmite of <1 year. The modelling for Pu17 suggests a 20% contribution from C1 - an instantaneous carbon source, which renders possible an immediate transfer of atmospheric signal into the cave. Nu16 shows a slower transfer of atmospheric carbon to the stalagmite than Pu17, with bomb radiocarbon onsetting in 1957 CE and peaking in 1972 CE. The less negative d13C values in Nu16 than Pu17, and also the modelling corroborated this, which points out no contribution from the instantaneous carbon source. The radiocarbon age models and laminae counting age models were then spliced to achieve a single master chronology for the top part of each stalagmite. This study is an example of 14C age modelling combined with visible physical and chemical laminae counting and how it can improve the accuracy and precision of dating for otherwise hard-to-date tropical Pacific speleothems. Such accurate and precise age models pave the way to obtain sub-annually resolved paleoclimate records by further improving the calibration of climate proxy data with the current and instrumental weather parameters.

Annually laminated stalagmites ER77 and ER78 from Grotta di Ernesto provide an accurate annual record of environmental and anthropogenic signals for the last ~200 years. Two major transitions are recorded in the stalagmites. The first coincides with the year 1840 CE, when a change from porous and impurity-rich-laminae to clean, translucent laminae occurs. This is accompanied by a steady increase in the growth rate, a decrease in fluorescence and a sharp increase in d13C values. These changes concur with the end of the Little Ice Age. The second transition takes place around the year 1960 CE and corresponds with an increase in both annual growth rate and sulfur concentration in stalagmite ER78 at 4.2 mm from the top, and with the deflection point in the 14C activity curve in stalagmite ER77 at 4.8 mm from the top. This latter is the stratigraphic signal proposed as the primary guide for the definition of the Anthropocene series. The following shift toward depleted d34S¿SO4 in stalagmite ER78 suggests that industrial pollution is a major source of sulfur. The interpretation of atmospheric signals (S, d34S, 14C) in the stalagmites is affected by attenuation and time lags and the environmental signals are influenced by soil and ecosystem processes, while other anthropogenic signals (d15N, 239Pu) are not recorded. For these reasons, the stalagmite record is here proposed as an auxiliary (reference) section rather than a global standard. In summary, Grotta di Ernesto contains one of the best stalagmite records documenting the Anthropocene, and one of only two stalagmite records where the S peak has been measured at high resolution.

The quality of climate proxy data from speleothem archives depends to varying degrees on crystallization processes, which result in diverse fabrics. Here, we document shifts in calcite growth mechanisms, from ion-by-ion to nanoparticle/nanocrystal attachment, in stalagmites from the tropical island of Atiu (South Pacific). Changes in solution stoichiometry and organic matter content result in the development of two columnar fabrics that are common elsewhere in settings characterized by seasonal contrast. A porous columnar fabric, characterized by intracrystalline micro and nanoporosity grows via a non-classical pathway through amorphous calcium carbonate (ACC) nanoparticles (~2¿4 nm in diameter) and calcite nanocrystal attachment. Despite subsequent transformation of nanoparticles/crystals into a large calcite crystal, the porous columnar fabric appears to preserve a d18O signal that faithfully reflects that of the parent fluid via quasi-equilibrium fractionation. Furthermore, the porous fabric shows random and fuzzy lateral distributions of Sr, another hydrological proxy, yet this element's incorporation follows equilibrium partitioning. The chemical properties of compact columnar fabrics, which appear to grow by classical ion-by-ion attachment, may not directly reflect those of the original depositional environment because of degassing, the presence of growth inhibitors (such as Na) and very early diagenetic modifications. Columnar porous calcite fabrics that formed through non-classical pathways in other settings may faithfully record the original properties of the parent drip water, whereas compact fabrics that formed through classical pathways elsewhere may not. It is concluded that the study of fabrics at the nano-scale is a necessary complement to speleothem research to identify the influence of crystallization pathways on the accuracy of proxy data.

Speleothem records of past environmental change provide an important opportunity to explore fire frequency and intensity in the past, and the antecedent climatic conditions leading to fire events. Here, fire sensitive geochemical signals in a stalagmite from Yonderup Cave, a shallow cave in Western Australia, are compared to well-documented wildfire events that occurred in recent decades. The results are extended to identify wildfires during the growth interval of the speleothem (1760 CE¿2005 CE). Principal component analysis of the stalagmite time-series revealed distinct peaks in a combination of phosphorus and metal (aluminium, zinc, copper and lead) concentrations in response to known fire events, which are interpreted to have come from ash. Varying responses in the geochemical signal in the pre- and post-European colonisation period are likely linked to changes in land management, fire frequency and fire intensities. Of note is what we infer to be a particularly intense fire event concluded to have occurred in 1897 ± 5 CE, which climate sensitive proxies (d18O and bedrock-derived elements) indicate was preceded by a multi-decadal dry period that began in the late 1860s. The intensity of the deduced fire event is supported by a peak in P that is 6.3 times higher than elsewhere in the speleothem, accompanied by a peak in Zn. It was also inferred that changes to the surface-cave hydrology occurred as a result of this event, indicated by increased input of colloidal organic material onto the stalagmite that was interpreted to be caused by shallow karst bedrock fracturing from the heat-induced deformation that is observed after intense fires. These findings show the potential for speleothems to provide dated records of fire intensity and recurrence intervals. Further development could lead to a better understanding of the climate-fire relationship and the effects of land-management practices on wildfire frequency and intensity.

Annually laminated speleothems have the potential to provide information on high-frequency climate variability and, simultaneously, provide good chronological constraints. However, there are distinct types of speleothem annual laminae, from physical to chemical, and a common mechanism that links their formation has yet to be found. Here, we analyzed annually laminated stalagmites from 23 caves and 6 continents with the aim to find if there are common mechanisms underlying their development. Annually laminated stalagmites are least common in arid and semiarid climates, and most common in regions with a seasonality of precipitation. At a global scale, we observe faster growth rates with increasing mean annual temperature and decreasing latitude. Changepoints in average growth rates are infrequent and age-depth relationships demonstrate that growth rates can be approximated to be constant. In general, annually laminated stalagmites are characterized by centennial-scale stability in calcite precipitation due to a sufficiently large and well-mixed water source, a time series spectrum showing first-order autoregression due to mixing of stored water and annual recharged water, and an inter-annual flickering of growth acceleration, bringing growth rates back to the long-term mean. Climate forcing of growth rate variations is observed where a multi-year climate signal is strong enough to be the dominant control on calcite growth rate variability, such that it retains a climate imprint after smoothing of this signal by mixing of stored water. In contrast, long-term constant growth rate of laminated stalagmites adds further robustness to their unparalleled capacity to improve accuracy of chronology building.

Tropical Pacific stalagmites are commonly affected by dating uncertainties because of their low U concentration and/or elevated initial 230Th content. This poses problems in establishing reliable trends and periodicities for droughts and pluvial episodes in a region vulnerable to climate change. Here we constrain the chronology of a Cook Islands stalagmite using synchrotron µXRF two-dimensional mapping of Sr concentrations coupled with growth laminae optical imaging constrained by in situ monitoring. Unidimensional LA-ICP-MS-generated Mg, Sr, Ba and Na variability series were anchored to the 2D Sr and optical maps. The annual hydrological significance of Mg, Sr, Ba and Na was tested by principal component analysis, which revealed that Mg and Na are related to dry-season, wind-transported marine aerosols, similar to the host-rock derived Sr and Ba signatures. Trace element annual banding was then used to generate a calendar-year master chronology with a dating uncertainty maximum of ± 15 years over 336 years. Our approach demonstrates that accurate chronologies and coupled hydroclimate proxies can be obtained from speleothems formed in tropical settings where low seasonality and problematic U¿Th dating would discourage the use of high-resolution climate proxies datasets.

Past climate archives show the Last Interglacial (LIG) period as similar to slightly warmer than current temperatures. However, there is a lack of LIG proxy evidence regarding variations of the climate across large topographic features and how this manifests at different altitudes. Here, we analysed two flowstones from Bigonda Cave, northeast Italy, to reconstruct LIG climate conditions in a region where precipitation is strongly influenced by the presence of the Alps. Stable isotope ratios, trace element concentrations and speleothem petrography from 133 ka to 105 ka allowed the detection of various hydroclimate and environmental conditions. Composite speleothem d18O records from northeast Italy were found to closely follow the Northern Hemisphere summer insolation curve, attesting to the influence of solar isolation on Earth's hydroclimate. Our reconstructions indicate a northward shift of the Intertropical Convergence Zone during the LIG maximum, permitting Atlantic-derived moisture to travel further east across North Africa than at present, before being directed north towards the Alps. The latter part of the LIG exhibited frequent, extreme precipitation events in the SE Prealps due to orographic lifting of moisture from both the Atlantic and Mediterranean seas. Socio-economic planning must prepare for extreme autumnal flooding events and serious summer droughts, particularly important in vulnerable mountainous regions.

Investigation by high resolution Transmission Electron Microscopy (HR-TEM) and Synchrotron-Radiation based micro X-ray fluorescence (SR-µXRF) of diagenesis in carbonates imposes uncertainties on the boundary between stages of crystal growth and post-depositional processes. Speleothems and dolomite are exemplars of the entire range of processes that result in solid materials consisting of crystals. HR-TEM investigation of speleothems suggests that there are many possible pathways of crystallization comprising classical ion-mediated, particle-mediated and formation of metastable phases. Diverse pathways influence the potential of a primary carbonate to undergo post-depositional transformation, with consequences on the accuracy of the preservation of original chemical and physical properties. The capability to date speleothems with U-series techniques is unique amongst other archives of Earth's history. It has been observed that U mobilization, which results in age inversions and uncertainties, is dependent on both crystallization and diagenetic pathways. Here, it is also proposed that the presence of organic colloids, mostly consisting of humic substances (HS), influences the extent to which U may be mobilized, as well as the capacity of original speleothem fabric to undergo dissolution and re-precipitation. Our hypothesis that colloidal HS protect the initial products of crystallization from subsequent diagenesis could explain the existence of primary dolomite preserved in Triassic sabkha facies influenced by fluvial input of siliciclastics. Primary dolomite nanocrystal aggregates coexist with single crystals, highlighting that multiple formation mechanisms were possible, which explains the variety of micro and nanostructures observed by conventional TEM investigations in dolomites. Similarly, we observed calcite nanocrystal aggregates and single crystals preserved in Triassic shallow marine facies, which are famous for their preservation of original aragonite, influenced by continental siliciclastic input. Our new data on the Triassic carbonates suggest that when HS colloids are abundant, nanocrystal aggregates are commonly preserved, possibly because of a protective coating by organic substances. These hinder both the transformation of the aggregates into larger crystals and multiple-steps diagenetic transformation that obliterate primary environmental signals. As opposed to textbook assumptions, it is here proposed that the existence of multiple crystallization pathways for carbonates within the same depositional environment, such as a cave setting or a sabkha, have repercussion on the early diagenetic processes and the extent to which diagenesis significantly resets the original chemical and physical signals. By using speleothems as paradigm for carbonates formed in natural environments where organic compounds are ubiquitous, the present review corroborates the notion that most mechanisms of carbonate crystallization, when the carbonate is not a biomineral, follow inorganic pathways. However, the role of organic substances, as inhibitors of growth and diagenesis, has profound influences on preservation of initial states of crystal formation.

The genesis of calcite coralloid speleothems from Lamalunga cave (Southern Italy) is here investigated from a purely petrographic perspective, which constitutes the basis for any subsequent chemical investigation. Lamalunga cave coralloids formed on bones and debris on the floor of the cave. They consist of elongated columnar crystals whose elongation progressively increases from the flanks to the tips of the coralloid, forming a succession of lens-shaped layers, which may be separated by micrite or impurity-rich layers. Organic molecules are preferentially concentrated toward the centre of convex lenses as highlighted by epifluorescence. Their occurrence on cave floor, lens-shaped morphology and concentration of impurities toward the apex of the convex lenses supports the hypothesis that their water supply was hydroaerosol, generated by the fragmentation of cave drips. Evaporation and degassing preferentially occurred on tips, enhancing the digitated morphology and trapping the organic molecules and impurities, carried by the hydroaerosol, between the growing crystals which became more elongated. Micrite layers, that cap some coralloid lenses, likely identify periods when decreasing in hydroaerosol resulted in stronger evaporation and higher supersaturation with respect to calcite of the parent film of fluid. This interpretation of coralloid formation implies that these speleothems can be used to extract hydroclimate information.

The reconstruction of robust past climate records from speleothems requires a prior understanding of the environmental and hydrological conditions that lead to speleothem formation and the chemical signals encoded within them. On regional-scales, there has been little quantification of the dependency of cave dripwater geochemistry on meteorology (net infiltration, temperature), environmental and geographical factors (elevation, latitude, soil activity, vegetation cover, atmospheric aerosol composition) and geological properties of the aquifer (lithology, porosity and thickness). In the present study, we analysed over 200 karst waters collected in 11 caves of the Trentino region (NE Italy). The caves span sub-humid Mediterranean to cold-humid temperate climates and infiltration elevations (Zinf) ranging from 355 to 2400 m a.s.l., corresponding to infiltration mean annual temperatures (MATinf) between 12 and 0 °C. Since all the caves developed in pure carbonate rocks, soil pCO2 is found to be the main factor controlling the carbonate dissolution. For this reason, the parameters controlling the carbonate-carbonic acid system and calcite saturation state (SICC) are directly correlated with the MATinf, which influences the vegetation zones and eventually the production of CO2 in the soil. SICC linearly depends on MATinf (SICC = 0.09 MATinf - 0.4) and SICC = 0 is reached at Zinf = 1.66 km a.s.l., corresponding to a MATinf = 4.4 °C. This point identifies the "speleothem limit" defined here as the elevation (or corresponding MATinf) above which no sparitic speleothem precipitation usually occurs. We demonstrate that due to temperature-forced changes in the soil and vegetation and subsequently SICC, the speleothem limit shifts to higher altitudes during maximum interglacial conditions. Speleothems from high altitude caves (1.5-2.5 km a.s.l.) thus can identify optimum interglacial periods. By contrast, speleothems formed at lower altitudes are better suited as archives of hydrological proxies. At altitudes below 1.2 km a.s.l., prior calcite precipitation (PCP) modifies percolating waters, particularly during periods of reduced infiltration. We introduce the use of the SiO2/Ca and SO4/Ca ratios in cave waters to complement Mg/Ca and Sr/Ca ratios as markers of PCP. SO4 and SiO2 are derived from atmospheric deposition and siliciclastic minerals in the soil zone, rather than carbonate host rocks (as in the case of Mg and Sr). By combing shifts to higher Mg/Ca, SiO2/Ca and SO4/Ca ratios along their characteristics PCP lines, we improve the robustness of the interpretation that this resulted from increasing PCP, rather than incongruent calcite dissolution (ICD). Our method permits the quantification of PCP between 0% and 40% for low elevation cave waters. This novel approach has important implications for speleothem-based paleoclimate studies where the distinction between PCP and ICD can be ambiguous and, in combination with Mg/Ca and Sr/Ca ratios, permits the quantification of net infiltration and/or rainfall amount from speleothem records.

Speleothems are usually considered as one of the most amenable palaeoclimate archives for U-series dating. A number of studies in recent years, however, report cases of diagenetic alteration which compromises the use of U-series systematics in speleothems, resulting in inaccurate U-Th ages. Here we present the results of a high-resolution U-Th dating study of a stalagmite (CC26) from Corchia Cave in Italy where we document a number of departures from an otherwise well-defined age-depth model, and explore potential causes for these outliers. Unlike examples illustrated in previous studies, CC26 contains no visible evidence of neomorphism, and appears, at least superficially, ideally suited to dating. Good reproducibility obtained between multi-aliquot U-Th analyses removes any possibility of analytical issues contributing to these outliers. Furthermore, replicate analyses of samples from the same stratigraphic layer yielded ages in stratigraphic sequence, implying very localized open-system behavior. Uranium loss is suggested as a causative mechanism on account of the fact that all the outliers are older than their assumed true age. A limited number of micro-voids were observed under micro-CT analyses, and it is proposed that these were pathways for U loss. Uranium-loss modelling allows us to constrain the possible timing of diagenetic alteration and indicates that the precursor for the outlier with the largest age discrepancy (309%) must have been aragonite. This study indicates that visibly unaltered speleothems may still contain small domains that have experienced post-depositional alteration. Such ¿cryptic¿ diagenesis, as recorded in this stalagmite, has implications for the constancy of accuracy of the U-series dating technique, and suggests a need for careful examination of speleothems prior to dating, particularly in low-resolution U-Th studies.

In the late Carnian (Late Triassic), a carbonate-clastic depositional system including a distal alluvial plain, flood basin and sabkha, tidal flat and shallow carbonate lagoon was established in the Dolomites (Northern Italy). The flood basin was a muddy supratidal environment where marine carbonates and continental siliciclastics interfingered. A dolomite phase made of sub-micrometre euhedral crystals with a mosaic microstructure of nanometre-scale domains was identified in stromatolitic laminae of the flood basin embedded in clay. This dolomite is interpreted here as primary and has a nearly stoichiometric composition, as opposed to younger early diagenetic (not primary) dolomite phases, which are commonly calcian. This primary dolomite was shielded from later diagenetic transformation by the clay. The stable isotopic composition of dolomite was analyzed along a depositional transect. The d13C values range between ca -6¿ and +4¿, with the most 13C-depleted values in dolomites of the distal alluvial plain and flood basin, and the most 13C-enriched in dolomites of the tidal flat and lagoon. Uniform d18O values ranging between 0¿ and +3¿ were found in all sedimentary facies. It is hypothesized that the primary dolomite with mosaic microstructure nucleated on extracellular polymeric substances secreted by sulphate reducing bacteria. A multi-step process involving sabkha and reflux dolomitization led to partial replacement and overgrowth of the primary dolomite, but replacement and overgrowth were facies-dependent. Dolomites of the landward, clay-rich portion of the sedimentary system were only moderately overgrown during late dolomitization steps, and partly retain an isotopic signature consistent with bacterial sulphate reduction with d13C as low as -6¿. In contrast, dolomites of the marine, clay-free part of the system were probably transformed through sabkha and reflux diagenetic processes into calcian varieties, and exhibit d13C values of ca +3¿. Major shifts of d13C values strictly follow the lateral migration of facies and thus mark transgressions and regressions.

The systematic documentation of calcite fabrics in stalagmites and flowstones provides robustness to palaeoclimate interpretation based on geochemical proxies, but it has been neglected because it is difficult to transform crystal morphologies into numerical values, and construct fabric time series. Here, general criteria that allow for coding fabrics of calcite composing stalagmites and flowstones is provided. Being based on known models of fabric development, the coding ascribes sequential numbers to each fabric, which reflect climaterelated parameters, such as changes in drip rate variability, bio-mediation or diagenetic modifications. Acronyms are proposed for Columnar types, Dendritic, Micrite, Microsparite and Mosaic fabrics, whose use could then render possible comparison of calcite fabrics in stalagmites and flowstones from diverse latitudinal and altitudinal settings. The climatic and environmental significance of similarities in the geochemical signals and trends analysed in coeval stalagmites and flowstones (or differences in the signals and trends) will be more robust when compared with fabric time series. This is particularly true where, such as in the Holocene, changes in geochemical values may be subtle, yet fabrics may show changes related to variations in supersaturation, drip rate or input of detrital particles or organic compounds. The proposed microstratigraphic logging allows recognition of changes in stable isotope ratio or trace element values that can be ascribed to hydrology and diagenesis, with considerable improvement of reconstructions based on the chemical proxies of stalagmites and flowstones composed of calcite.

The European Alps are an effective barrier for meridional moisture transport and are thus uniquely placed to record shifts in the North Atlantic storm track pattern associated with the waxing and waning of Late-Pleistocene Northern Hemisphere ice sheets. The lack of well-dated terrestrial proxy records spanning this time period, however, renders the reconstruction of past atmospheric patterns difficult. Here we present a precisely dated, continuous terrestrial record of meteoric precipitation in Europe between 30 and 14.7 ka. In contrast to present-day conditions, our speleothem data provide strong evidence for preferential advection of moisture from the South across the Alps supporting a southward shift of the storm track during the local Last Glacial Maximum (that is, 26.5-23.5 ka). Moreover, our age control indicates that this circulation pattern preceded the Northern Hemisphere precession maximum by ~3 ka, suggesting that obliquity may have played a considerable role in the Alpine ice aggradation.

Sulphate concentrations in speleothems identify major volcanic eruptions, provide useful information on soil and aquifer dynamics and, in similar fashion to the ¹⁴C bomb peak, its Anthropocene peak can be used to date recent cave formations. However, the transmission of S from the atmosphere to cave dripwater and its incorporation in speleothems is subjected to biogeochemical cycling and accurate studies of each cave site are needed in order to assess how the S atmospheric signal is modified and eventually encoded in speleothems. This study investigates the role of biogeochemical cycling and aquifer hydrology by utilising published and new dripwater and speleothem data from Grotta di Ernesto (ER) in northern Italy. Here we provide the first long-term record of sulphate concentration in cave dripwater based on over 20 years of measurements. Fast drip site st-ER1 is characterised by a continuous decrease in SO<inf>4</inf> concentration from a high of 7.5±0.8mg/l in 1993-1994 to a low of 2.2±0.2mg/l in 2013-2014, and replicates with a delay of ~15 years the decline in the atmospheric SO<inf>2</inf> emissions. The S-series of slow flow ER78 site is further delayed by ~4.5 years in relation to the S retention in the aquifer matrix. The dripwater data are used to extend the previously published S record (1810-1998 AD) of stalagmite ER78 and reconstruct the anthropogenic S-peak: this displays a delay of ~20 years with respect to the atmospheric S emission peak due to biogeochemical cycling and aquifer storage. However, sulphur recycling above the cave did not operate with the same degree of efficiency through time, which resulted in a variable time delay between S deposition and incorporation into the stalagmite. In the pre-Anthropocene era, and in particular during the cold Little Ice Age, biogeochemical cycling was far less efficient than today, and the fast transmission of the atmospheric signal allowed capture of S released during major volcanic eruptions by stalagmites.

Terrestrial records of past climatic conditions, such as lake sediments and speleothems, provide data of great importance for understanding environmental changes. However, unlike marine and ice core records, terrestrial palaeodata are often not available in databases or in a format that is easily accessible to the non-specialist. As a consequence, many excellent terrestrial records are unknown to the broader palaeoclimate community and are not included in compilations, comparisons, or modelling exercises. Here we present a compilation of Western European terrestrial palaeo-records covering, entirely or partially, the 60-8-ka INTIMATE time period. The compilation contains 56 natural archives, including lake records, speleothems, ice cores, and terrestrial proxies in marine records. The compilation is limited to include records of high temporal resolution and/or records that provide climate proxies or quantitative reconstructions of environmental parameters, such as temperature or precipitation, and that are of relevance and interest to a broader community. We briefly review the different types of terrestrial archives, their respective proxies, their interpretation and their application for palaeoclimatic reconstructions. We also discuss the importance of independent chronologies and the issue of record synchronization. The aim of this exercise is to provide the wider palaeo-community with a consistent compilation of high-quality terrestrial records, to facilitate model-data comparisons, and to identify key areas of interest for future investigations. We use the compilation to investigate Western European latitudinal climate gradients during the deglacial period and, despite of poorly constrained chronologies for the older records, we summarize the main results obtained from NW and SW European terrestrial records before the LGM.

Mounting evidence exists that variations in sulphur content in stalagmites are closely linked to changes in volcanic or anthropogenic atmospheric sulphur. The strong dependency of sulphur on soil pH and ecosystem storage, however, can result in a delay of several years to decades in the registration of volcanic eruptions and anthropogenic emissions by stalagmites. Here we present synchrotron-radiation based trace element analysis performed on a precisely-dated section of a stalagmite from Sofular Cave in Northern Turkey. As this section covers the time interval of the intensively studied Minoan volcanic eruption between 1600 and 1650 BC, we can test whether this vigorous eruption can be traced in a stalagmite. Of all measured trace elements, only bromine shows a clear short-lived peak at 1621 ± 25 BC, whereas sulphur and molybdenum show peaks later at 1617 ± 25 and 1589 ± 25 respectively. We suggest that all trace element peaks are related to the Minoan eruption, whereas the observed phasing of bromine, molybdenum and sulphur is related to differences in their retention rates in the soil above Sofular Cave. For the first time, we can show that bromine appears to be an ideal volcanic tracer in stalagmites, as it is a prominent volatile component in volcanic eruptions, can be easily leached in soils and rapidly transferred from the atmosphere through the soil and bedrock into the cave and stalagmite respectively. Highly resolved oxygen and carbon isotope profiles indicate that the Minoan eruption had no detectable climatic and environmental impact in Northern Turkey. © 2014 Elsevier B.V.

Both aggregation and mineral association have been previously found to enhance soil organic carbon (SOC) storage (the amount of organic C retained in a soil), and stability (the length of time organic C is retained in a soil). These mechanisms are therefore attractive targets for soil C sequestration. In this study, we investigate and compare SOC storage and stability of SOC associated with fine minerals and stored within aggregates using a combination of particle-size fractionation, elemental analysis and radiocarbon dating. In this heavy-textured, highly aggregated soil, SOC was found to be preferentially associated with fine minerals throughout the soil profile. By contrast, the oldest SOC was located in the coarsest, most highly aggregated fraction. In the topsoil, radiocarbon ages of the aggregate-associated SOC indicate retention times in the order of centuries. Below the topsoil, retention times of aggregate-SOC are in the order of millennia. Throughout the soil profile, radiocarbon dates indicate an enhanced stability in the order of centuries compared with the fine mineral fraction. Despite this, the radiocarbon ages of the mineral-associated SOC were in the order of centuries to millennia in the subsoil (30-100cm), indicating that mineral-association is also an effective stabilisation mechanism in this subsoil. Our results indicate that enhanced SOC storage does not equate to enhanced SOC stability, which is an important consideration for sequestration schemes targeting both the amount and longevity of soil carbon. © CSIRO 2014.

In 1993, a fossil hominin skeleton was discovered in the karst caves of Lamalunga, near Altamura, in southern Italy. Despite the fact that this specimen represents one of the most extraordinary hominin specimens ever found in Europe, for the last two decades our knowledge of it has been based purely on the documented on-site observations. Recently, the retrieval from the cave of a fragment of bone (part of the right scapula) allowed the first dating of the individual, the quantitative analysis of a diagnostic morphological feature, and a preliminary paleogenetic characterization of this hominin skeleton from Altamura. Overall, the results concur in indicating that it belongs to the hypodigm of Homo neanderthalensis, with some phenetic peculiarities that appear consistent with a chronology ranging from 172±15ka to 130.1±1.9ka. Thus, the skeleton from Altamura represents the most ancient Neanderthal from which endogenous DNA has ever been extracted.

Calcite moonmilk, which is a cave deposit formed of calcite crystals and water, is found in many caves in the Italian Alps. These modern and ancient deposits are formed of fiber calcite crystals, 50-500 nm wide and 1 to > 10 µm long, and pol) crystalline chains that have few crystal defects. Radiocarbon dating indicates that most moonmilk deposits in these caves are fossil and that for most precipitation ceased ~ 6400 cal years BP, at the end of the mid-Holocene Hypsithermal. In the caves of the Italian Alps, the optimal conditions for formation of calcite moonmilk are: (1) a temperature range of 3.5-5.5°C, (2) low discharge volumes of seepage waters that are slightly supersaturated (SICAL = 0.0 to ~ 0.2), and (3) relative humidity that is at or close to 100%. Microbial activity apparently did not play an active role in the formation of the calcite moonmilk. Conditions for moonmilk formation are typically found in caves that are located beneath land surfaces, which are soil covered and support a conifer forest. Precipitation of the fiber calcite crystals apparently involved very slow flow of slightly supersaturated fluids. The fact that moonmilk appears to form under a narrow range of environmental conditions means that this cave deposit has potential as a paleodimatic indicator in high alpine karst areas. Copyright ©2000, SEPM (Society for Sedimentary Geology).

Calcite moonmilk, which is a cave deposit formed of calcite crystals and water, is found in many caves in the Italian Alps. These modern and ancient deposits are formed of fiber calcite crystals, 50-500 nm wide and 1 to > 10 µm long, and polycrystalline chains that have few crystal defects. Radiocarbon dating indicates that most moonmilk deposits in these caves are fossil and that for most precipitation ceased ~ 6400 cal years BP, at the end of the mid-Holocene Hypsithermal. In the caves of the Italian Alps, the optimal conditions for formation of calcite moonmilk are: (1) a temperature range of 3.5-5.5°C, (2) low discharge volumes of seepage waters that are slightly supersaturated (SICAL= 0.0 to ~ 0.2), and (3) relative humidity that is at or close to 100%. Microbial activity apparently did not play an active role in the formation of the calcite moonmilk. Conditions for moonmilk formation are typically found in caves that are located beneath land surfaces, which are soil covered and support a conifer forest. Precipitation of the fiber calcite crystals apparently involved very slow flow of slightly supersaturated fluids. The fact that moonmilk appears to form under a narrow range of environmental conditions means that this cave deposit has potential as a paleoclimatic indicator in high alpine karst areas. Copyright © 2000, SEPM (Society for Sedimentary Geology).

One of the themes AIQUA has intended to develop its own work on in the three years, 1998-2000, has been that on the climatic evolution in the last 10,000 years. An original approach has been thought of that combines geological, naturalistic, archeological and historical data ect. Thus, a working group formed by experts in different subjects has been created, whose objective has been to produce extended abstracts on research and the results of paleoclimatic studies regarding different markers. The sources of paleoclimatic proxy data discussed are: glacial variations in the Alps, sea and lake level fluctuations, sea surface temperature fluctuations, historical data series, pollen sequences, speleothem isotope and trace elements profiles, travertine analysis and ice core isotope and dust mineralogy profiles. Finally, an updating of the14C methodology and calibration has been carried out. The period under study decided upon is the Holocene, as defined by Orombelli &amp; Ravazzi (1996) and by Walker etal. (1999). Thus, the Holocene starts from a14C conventional age of 10 ka BP, between 11263 and 11549 years BP according to Stuiver et al. (1998) calibration (for atmosphere), or 11500 years according to the counting of annual layers in GRIP ice core. The authors have reproposed to summarize results and metodology regarding Italian paleoclimatic research, with wide reference to that of the whole world.

In the frame of discussion on speleothem sedimento-logy we introduce a particular subclass of speleothemes undergoing accretion both in the continental (subaerial dripstones) and marine (marine organic overgrowth) environments, and describes the chemical-phisycal aspects of speleotheme growth. Hus allows a correct use of this speleothem subclass in paleoclimatic and eustatic investigation. Applications and limits of the most common datation techniques (U/Th,14C) to the chronological reconstructions of sea level oscillations are outlined. The significance of speleothemes wide marine overgrowth as paleoclimatic indicators through the analysis of variations in oxygen and carbon isotopie rations is also discussed (d;18O e d13C). The integrations of informations deriving from continental and submerged speleothem allow detailed paleoenvironmental reconscrutions to be made. Durin glacial-interglacial oscillations, an encrease of d;18O indicate cooling, and marine organogenic overgrowth on speleothemes allows the precise detection of submsion timing.

Archaeometric investigation on the Gaban Venus - The authors present the results of a fully non-destructive multianalytical approach applied to the study of the Gaban Venus in order to identify the modalities of its manufacture and painting. The osseous artifact comes from the Neolithic levels of the eponymous site, located near Trento. The results of the archaeometrical and microscopical analyses carried out on the object allowed to reveal the nature of the pigments used for painting it as well as the coexistence of both Mesolithic and Neolithic technological traditions for the manufacture . © Museo delle Scienze, Trento 2012.

The present work has been performed in the framework of the research project AQUAPAST. The main focus of AQUAPAST is the reconstruction of past climate changes in the atmospheric circulation and in particular in the water vapour transport mechanism over the Mediterranean area starting from the analysis of the isotopic content of cave speleothemes in the Trentino Province (North-East of Italy). A Lagrangian methodology for the reconstruction and the analysis of the airstreams which govern the transport of water vapour has been applied to recent events. The average monthly isotopic signal of the precipitation water sampled in stations located in key geographic settings in the Province of Trento is used as tracer to infer the origin of the precipitating water and to validate Lagrangian analysis. A comparison between the isotopic signal of November 2002 and November 2003 is here presented, as most of the yearly precipitation falls in November over the Eastern Alps. Hypotheses are proposed about the meteorological factors (e.g. monthly averaged sea surface temperature atmospheric circulation, etc.) determining different isotopic signal in the two years.