Andrea Borsato

The University of Newcastle, Australia · Department of Earth Sciences

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)...

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...

This study utilizes speleothem trace elements as climate proxies to reconstruct hydroclimate variability over approximately 350 years in the Southern Cook Islands. Stalagmites Pu17 and Pu4 from Pouatea cave were analyzed using high-resolution LA-ICP-MS for trace elements (Mg, Na, Sr, P, U, Y). By monitoring cave dripwater and conducting regression...

Cave carbonate mineral deposits (speleothems) contain trace elements that are intensively investigated for their significance as palaeoclimate and environmental proxies. However, chlorine, which is abundant in marine and meteoric waters, has been overlooked as a potential palaeo-proxy, while cosmogenic 36 Cl could, in principle, provide a solar irr...

Palaeoclimate information on multiple climate variables at different spatiotemporal scales is becoming increasingly important to understand environmental and societal responses to climate change. A lack of high-quality reconstructions of past hydroclimate has recently been identified as a critical research gap. Speleothems, with their precise chron...

Palaeoclimate information on multiple climate variables at different spatiotemporal scales is becoming increasingly important to understand environmental and societal responses to climate change. A lack of high-quality reconstructions of past hydroclimate has recently been identified as a critical research gap. Speleothems, with their precise chron...

Lamalunga Cave (Altamura, Southern Italy) is renowned for the discovery in 1993 of an excellently preserved Neanderthal skeleton. Given the importance of the findings and the potential use of Lamalunga speleothems for paleoclimate reconstructions, a detailed monitoring program was undertaken to investigate the connections between microclimate param...

The 8.2 ka event is the most significant global climate anomaly of the Holocene epoch, but a lack of records from Mainland Southeast Asia (MSEA) currently limits our understanding of the spatial and temporal extent of the climate response. A newly developed speleothem record from Tham Doun Mai Cave, Northern Laos provides the first high‐resolution...

Complete Neanderthal skeletons are almost unique findings. A very well-preserved specimen of this kind was discovered in 1993 in the deepest recesses of a karstic system near the town of Altamura in Southern Italy. We present here a detailed description of the cranium, after we virtually extracted it from the surrounding stalagmites and stalactites...

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 stoic...

The hydroclimate of the South Pacific is highly variable on a range of timescales, however, the brevity of instrumental data in the region complicates the detection and attribution of this variability. Annually laminated speleothems may fill this knowledge gap by providing paleo-hydroclimate proxy data extending beyond the instrumental period. In t...

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 wildfir...

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)...

Speleothem oxygen isotopic (δ18O) records are used to reconstruct past hydroclimate yet records from the same cave do not always replicate. We use a global database of speleothem δ18O to quantify the replicability of records to show that disagreement is common worldwide, occurs across timescales and is unrelated to climate, depth or lithology. Our...

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...

Annually laminated stalagmites are an exceptional archive of high-resolution past hydroclimate changes and provide robust annually-resolved age models. Stalagmite chemical annual laminae are invisible through optical and fluorescence microscopy, but are revealed by X-ray fluorescence or mass-spectrometry techniques. Synchrotron radiation based micr...

Raponzolo is a paleo-phreatic cave explored in 2011 in the Brenta Dolomites (Trentino, Italy), at the remarkable altitude of 2,560 m a.s.l. Differently to all other caves of the area, it hosts well-cemented fine to medium sands of granitic-metamorphic composition. The composition suggests a sediment source from the Adamello and Tonale Unit, separat...

Climate and environmental events recorded by speleothems are accurately dated by radiometric techniques. However, speleothems from the Tropical Pacific are difficult to date by the U-series radiometric method due to low uranium content and/or multiple sources of 230 Th. This is the case of stalagmites from Atiu, in the Southern Cook Islands Archipe...

A global investigation discovers where annually laminated stalagmites are found, analyzes their growth properties, and explains how they can be best used in Earth science research.

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 analyze...

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 st...

Although quantitative isotope data from speleothems has been used to evaluate isotope-enabled model simulations, currently no consensus exists regarding the most appropriate methodology through which to achieve this. A number of modelling groups will be running isotope-enabled palaeoclimate simulations in the framework of the Coupled Model Intercom...

Synchrotron high‐resolution and micro‐X‐ray fluorescence elemental mapping of two coeval coralloid speleothems from Lamalunga Cave (Italy) are complemented with petrographic, morphological and microstratigraphic studies. The importance of these speleothems relies on their direct and indirect association with a complete Neanderthal skeleton (‘Altamu...

A stalagmite (FR16) from Frasassi Cave, located near the Adriatic coast of the Italian peninsula, offers a 16 kyr petrographic and stable isotope record spanning from 112.8 ± 1.5 ka to 96.6 ± 1.0 ka, corresponding to the interval from marine isotope stage (MIS) 5c to MIS 5d. The physical characteristics of FR16 calcite, allowed for a thorough under...

Thermophilisation is the response of plants communities in mountainous areas to increasing temperatures, causing an upward migration of warm-adapted (thermophilic) species and consequently, the timberline. This greening, associated with warming, causes enhanced evapotranspiration that leads to intensification of the hydrological cycle, which is rec...

Carbonate-associated sulphate (CAS) is a useful carrier of palaeoenvironmental information throughout the geologic record, particularly through its stable isotope composition. However, a paucity of experimental data restricts quantitative understanding of sulphate incorporation into carbonates, and consequently CAS concentrations and their diagenet...

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 elongat...

Terrestrial data spanning the Last Glacial Maximum (LGM) and deglaciation from the southern Australian region are sparse and limited to discontinuous sedimentological and geomorphological records with relatively large chronological uncertainties. This dearth of records has hindered a critical assessment of the role of the Southern Hemisphere mid-la...

Marine sediment records suggest that episodes of major atmospheric CO2 drawdown during the last glacial period were linked to iron (Fe) fertilization of subantarctic surface waters. The principal source of this Fe is thought to be dust transported from southern mid-latitude deserts. However, uncertainty exists over contributions to CO2 sequestratio...

Supplementary Figures, Supplementary Table and Supplementary References

list of Boggs Valley subglacial calcite samples analysed for DNA. Sample BV11, consisting of angular clasts cemented by microsparite, is sterile (see text for details.)

OTU data in .Biom format relative to samples BV8a and BV9b.

OTU .txt file relative to the DNA data for Boggs Valley calcite samples BV8a and BV9b. BV 11 is sterile.

In this study, the ‘dead carbon proportion’ (DCP) calculated from combined U-Th and radiocarbon analyses was used to explore the carbon isotope systematics in Corchia Cave (Italy) speleothems, using the example of stalagmite CC26 which grew during the last ~12 ka. The DCP values in CC26 are among the highest ever recorded in a stalagmite, spanning...

Speleothems and other carbonate deposits such as tufa containing high proportions of detrital material can be difficult to chemically date due to detrital thorium levels causing a high level of error in conventional U-Th disequilibrium dating. Here we investigate the use of an alternative technique centring on radiocarbon dating of organic matter p...

Terrestrial data spanning the Last Glacial Maximum (LGM) and deglaciation from the southern Australian region are sparse, and limited to discontinuous sedimentological and geomorphological records with relatively large chronological uncertainties. This dearth of records has prevented a critical assessment of the role of the Southern Hemisphere mid-...

Il Foglio 079 – Bagolino della Carta Geologica d‟Italia a scala 1:50.000 è stato realizzato nell‟ambito del Progetto CARG (Legge 226/1999), attraverso convenzioni tra il Servizio Geologico d‟Italia, la Regione Lombardia e la Provincia Autonoma di Trento che hanno affidato il Coordinamento Scientifico del Foglio al’Università degli Studi di Bologna....

The trace element and Sr isotope records in two coeval stalagmites characterized by different growth rates and flow regimes at Savi Cave (Grotta Savi, NE Italy) reveal different sources and incorporation mechanisms for Mg and Sr. Mg is sourced primarily from dissolved cave host rock while particulate Mg derived from soil plays a subordinate role. T...

Organic phosphorus incorporated in calcite during laboratory precipitation experiments and in natural cave deposits was investigated by solid-state NMR spectroscopy. For calcite precipitated in the presence of organic phosphoesters of varying size and functionality, solid-state 31P{1H} CP/MAS NMR shows that the phosphoesters were incorporated intac...

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 (n...

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 (n...

Carbon dioxide (CO 2 ) concentrations in caves and parent soils in the Italian Alps have been studied along a 2100 m altitudinal range – corresponding to a mean annual temperature (MAT) range of 12°C – in order to investigate the relationship between MAT, soil pCO 2 and cave air pCO 2 , and to test the influence of soil pCO 2 on speleothem growth a...

Carbon dioxide (CO2) concentrations in caves and parent soils in the Italian Alps have been studied along a 2100m altitudinal range – corresponding to a mean annual temperature (MAT) range of 12°C – in order to investigate the relationship between MAT, soil pCO2 and cave air pCO2, and to test the influence of soil pCO2 on speleothem growth and fabr...

While springs have provided important study sites for hydrogeology since the beginning of this discipline, spring biology (crenobiology) is only about 50 years old, and the term “crenoecology” has been used only recently and sporadically. Moreover, springs have mostly been studied in isolation by ecologists and hydrogeologists. Ecological studies o...

While springs have provided important study sites for hydrogeology since the beginning of this discipline, spring biology (crenobiology) is only about 50 years old, and the term “crenoecology” has been used only recently and sporadically. Moreover, springs have mostly been studied in isolation by ecologists and hydrogeologists. Ecological studies o...

Carbon dioxide concentration in soils controls carbonate dissolution, soil CO 2 efflux to the atmosphere, and CO 2 transfer to the subsurface that lead, ultimately, to speleothem precipitation. Systematic studies on CO 2 concentration variability in soil and caves at regional scale are, however, few. Here, the systematic investigation of CO 2 conce...

Available online xxxx Editor: G.M. Henderson Keywords: Minoan eruption volcanic eruption stalagmite trace elements Turkey eastern Mediterranean 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 eco...

Lake Tovel is an oligotrophic, meromictic, mountain lake of the Dolomites that undergoes marked seasonal water-level fluctuations (WLFs). We used neo- and paleolimnological data collected since 1999 to test the utility of algal and cyanobacterial pigments and diatom and chironomid biodiversity as proxies for WLF and to highlight the contribution of...

The interpretation of stable isotope ratios in speleothem calcite is complex, and only in a few cases, unequivocal relationships with palaeoclimate parameters have been attained. A major issue is temperature, which has an effect on both the isotope incorporation into calcite and on environmental processes. Here, a field approach is taken, by studyi...

The distribution of phosphorous (P) in one modern and two Early Pliocene speleothems formed in low-lying, Christmas Island and the coastal Nullarbor caves wet settings in Australia is here investigated by microscopy and ultra-high resolution chemical mapping. Monitoring data in the modern setting suggest that co-precipitation of P with calcite occu...

Phosphorus (P) is potentially a very important environmental proxy in speleothem palaeoclimate reconstructions. However, the transfer of P to a speleothem seems to vary between cave sites. Therefore, it is important to investigate the source of P and the way it is incorporated into a speleothem on a site-by-site basis before it can be used as a rob...

Interpreting stable oxygen isotope (δ¹⁸O) records from stalagmites is still one of the complex tasks in speleothem research. Here, we present a novel model-based approach, where we force a model describing the processes and modifications of δ¹⁸O from rain water to speleothem calcite (Oxygen isotope Drip water and Stalagmite Mo...

Here we present high-resolution stable isotope and lamina thickness profiles as well as radiocarbon data for the Holocene stalagmite ER 76 from Grotta di Ernesto (North-Eastern Italy), which was dated by combined U-series dating and lamina counting. ER 76 grew between 8 ka (thousands of years before 2000 AD) and today, with a hiatus from 2.6 to 0.4...

Here we present high-resolution stable isotope and lamina thickness profiles as well as radiocarbon data for the Holocene stalagmite ER 76 from Grotta di Ernesto (north-eastern Italy), which was dated by combined U-series dating and lamina counting. ER 76 grew between 8 ka (thousands of years before 2000 AD) and today, with a hiatus from 2.6 to 0.4...

Large changes of the climate can dramatically affect the environment surrounding and within a cave. This variability, including temperature shifts, can change the amount of in-cave isotopic fractionation affecting speleothems, potentially leaving these records difficult to interpret. Here, caves located in steep altitudinal topography in the Northe...

Trace amounts of sulphur in speleothems suggest that stalagmites may act as archives of sulphur deposition, thereby recording aspects of atmospheric variability in sulphur content. Accurate interpretation of this novel sulphur archive depends upon understanding how biogeochemical cycling in the soil and epikarst above the cave may modify the precur...

This paper aims to establish evidence for the widespread existence of metal binding and transport by natural organic matter (NOM) in karst dripwaters, the imprint of which in speleothems may have important climatic significance. We studied the concentration of trace metals and organic carbon (OC) in sequentially filtered dripwaters and soil leachat...

Tephra layers in marine and lacustrine sediments are crucial for chronostratigraphic dating. However, tephrachronologies based on marine and lake sediments suffer from age uncertainties due to low sedimentation rates, biturbation and inherent problems associated with radiocarbon dating (e.g. hardwater effect, varying marine reservoir ages). A poten...

Early Holocene climate variability is more complex than previously thought, and it is becoming clearer that several abrupt short-term climate reversals occurred after the Younger Dryas (YD). The 8.2 ka cold reversal is the most documented event but there is evidence for other post-YD events. These have been linked to the Pre-Boreal Oscillation (PBO...

Diverse interpretations have been made of carbon isotope time series in speleothems, reflecting multiple potential controls. Here we study the dynamics of 13C and 12C cycling in a particularly well-constrained site to improve our understanding of processes affecting speleothem δ13C values. The small, tubular Grotta di Ernesto cave (NE Italy) hosts...

Grotta di Ernesto is a cave site well suited for palaeoclimate studies because it contains annually laminated stalagmites and was monitored from 1995 to the end of 2008 for microclimate, hydrology and hydrochemistry. Long-term monitoring highlighted that cave drips show three different hydrological responses to rainfall and infiltration: (1) fast s...

Seasonality is encoded in palaeoproxies of secondary cave mineral deposits (speleothems) and the code is becoming cracked. The petrology of calcite stalagmites from Obir, an Alpine (1100 m altitude), perennially wet cave, was characterized by optical and electron backscatter diffraction, and their chemistry by bulk ICP-MS analysis, ion microprobe a...

Karst environments are regions where sparingly soluble rocks outcrop and efficient acid hydrolysis creates spectacular dissolution landforms. The release of CO2 from karst waters to the atmosphere causes precipitation of calcium-carbonate deposits, which, in caves, are collectively known as speleothems. Karst carbonate deposits capture climate and...

Sulphur emitted into the atmosphere from industrial activity is regarded as a key mechanism in forcing recent climate and has impacts upon the environment and human health at both local and regional scales. Trace amounts of sulphate present within speleothem carbonate can be used to provide an emissions inventory for regional sulphur loading to the...

Zooplankton abundance was related to hydrological and environmental variables in a hydrologically dynamic lake fed by a pseudokarstic aquifer. The study period (2002–2006) in Lake Tovel covered different hydrological situations with water residence time (WRT) having the lowest values in 2002 and the highest values in 2003. WRT was negatively correl...

Karst environments are regions where sparingly soluble rocks outcrop and efficient acid hydrolysis creates spectacular dissolution landforms. The release of CO₂ from karst waters to the atmosphere causes precipitation of calcium-carbonate deposits, which, in caves, are collectively known as speleothems. Karst carbonate deposits capture c...

We used the quantitative theory of solubility of karst rocks of Shopov et. al, (1989, 1991a) in dependence of the temperature and other thermodynamic parameters to make reconstructions of past carbonate denudation rates. This theory produced equations assessing the carbonate denudation rates in dependence on the temperature or on the precipitation....