ORCID Profile
0000-0001-6568-2696
Current Organisation
The University of Newcastle
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Physical Geography and Environmental Geoscience | Palaeoclimatology | Quaternary Environments | Climatology (Incl. Palaeoclimatology) | Geochronology | Mineralogy and Crystallography | Hydrogeology | Geology | Environmental Science and Management | Physical geography and environmental geoscience | Alloy Materials | Natural Resource Management | Organic Geochemistry Not Elsewhere Classified | Climatology (excl. Climate Change Processes) | Isotope Geochemistry | Natural hazards | Palaeoclimatology | Climate change processes | Cellular Interactions (Incl. Adhesion, Matrix, Cell Wall) | Materials Engineering | Diagnostic Applications | Environmental Sciences Not Elsewhere Classified | Sedimentology |
ANZSRC Socio-Economic Objective (SEO)
Climate variability | Effects of Climate Change and Variability on New Zealand (excl. Social Impacts) | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Climate Change Adaptation Measures | Land and water management | Field crops | Climate Change Models | Earth sciences | Concentrating processes of other base metal ores | Energy transformation not elsewhere classified | Water Allocation and Quantification | Climate and Climate Change not elsewhere classified | Effects of Climate Change and Variability on the South Pacific (excl. Australia and New Zealand) (excl. Social Impacts)
Related Links
Publications
From soil to cave: Transport of trace metals by natural organic matter in karst dripwaters
Publisher: Elsevier BV
Date: 04-2012
Genesis and microstratigraphy of calcite coralloids analysed by high resolution imaging and petrography
Publisher: Elsevier BV
Date: 08-2017
“Cryptic” diagenesis and its implications for speleothem geochronologies
Publisher: Elsevier BV
Date: 09-2016
Vertical distribution of charcoal in a sandy soil: Evidence from DRIFT spectra and field emission scanning electron microscopy
Publisher: Wiley
Date: 09-2014
DOI: 10.1111/EJSS.12171
Hydroclimate of the Last Glacial Maximum and deglaciation in southern Australia's arid margin interpreted from speleothem records (23-15 ka)
Publisher: Copernicus GmbH
Date: 14-06-2017
Abstract: Abstract. 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-latitude westerly winds on the region's climate during this time period. In this study, two precisely dated speleothem records for Mairs Cave, Flinders Ranges, are presented, providing for the first time a detailed terrestrial hydroclimatic record for the southern Australian drylands during 23–15 ka. Recharge to Mairs Cave is interpreted from the speleothem record by the activation of growth, physical flood layering, and δ18O and δ13C minima. Periods of lowered recharge are indicated by 18O and 13C enrichment, primarily affecting δ18O, argued to be driven by evaporation of shallow soil/epikarst water in this water-limited environment. A hydrological driver is supported by calcite fabric changes. These include the presence of laminae, visible organic colloids, and occasional dissolution features, related to recharge, as well as the presence of sediment bands representing cave floor flooding. A shift to slower-growing, more compact calcite and an absence of lamination is interpreted to represent reduced recharge. The Mairs Cave record indicates that the Flinders Ranges were relatively wet during the LGM and early deglaciation, particularly over the interval 18.9–15.8 ka. This wetter phase ended abruptly with a shift to drier conditions at 15.8 ka. These findings are in agreement with the geomorphic archives for this region, as well as the timing of events in records from the broader Australasian region. The recharge phases identified in the Mairs Cave record are correlated with, but antiphase to, the position of the westerly winds interpreted from marine core MD03-2611, located 550 km south of Mairs Cave in the Murray Canyons region. The implication is that the mid-latitude westerlies are located further south during the period of enhanced recharge in the Mairs Cave record (18.9–16 ka) and conversely are located further north when greater aridity is interpreted in the speleothem record. A further comparison with speleothem records from the northern Australasian region reveals that the availability of tropical moisture is the most likely explanation driving enhanced recharge, with further lification of recharge occurring during the early half of Heinrich Stadial 1 (HS1), possibly influenced by a more southerly displaced Intertropical Convergence Zone (ITCZ). A rapid transition to aridity at 15.8 ka is consistent with a retraction of this tropical moisture source.
High spatial resolution investigation of nucleation, growth and early diagenesis in speleothems as exemplar for sedimentary carbonates
Publisher: Elsevier BV
Date: 03-2018
High‐resolution synchrotron X‐ray fluorescence investigation of calcite coralloid speleothems: Elemental incorporation and their potential as environmental archives
Publisher: Wiley
Date: 28-06-2019
DOI: 10.1111/SED.12607
Crystallization pathways, fabrics and the capture of climate proxies in speleothems: Examples from the tropics
Publisher: Elsevier BV
Date: 12-2022
A re-evaluation of the palaeoclimatic significance of phosphorus variability in speleothems revealed by high-resolution synchrotron micro XRF mapping
Publisher: Copernicus GmbH
Date: 14-12-2012
Abstract: Abstract. 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 robust palaeoclimate proxy. In this paper, the distribution of P in one modern and two Early Pliocene speleothems formed in coastal caves on Christmas Island (Indian Ocean) and the Nullarbor Plain (southern Australia) is investigated using microscopy and ultra-high resolution chemical mapping. Phosphorus has been found to be both incorporated in the lattice and present as erse P-rich phases. Monitoring data from Christmas Island suggest that co-precipitation of P-rich phases occurs when "prior calcite precipitation" decreases following recharge, even if the drip rate decreases. Microbial mediation may also play a role, which complicates a direct climate relationship between P and hydrology. We find that some P-enriched layers contain dissolution features, with possible involvement of microbial mats which colonise pores during reduced drip rates associated with prolonged dry spells. In the two Early Pliocene speleothems the relationship between P and microbial laminae is clearer. Both petrographic and chemical data suggest that phosphorus-rich phases in the microbial laminae mark intervals of reduced drip rates, which may indicate dry intervals during the otherwise wet palaeoclimate of the Early Pliocene. We develop a speleothem distribution coefficient for phosphorus (SKP) rather than the thermodynamic partition coefficient (KP) to account for the presence of crystalline phosphate inclusions. SKP describes P enrichment in speleothems regardless of the process, as similar mechanisms of phosphate co-precipitation may be in operation in biotic and abiotic conditions. The most important implication of our study is that variability in P concentration may be related to erse processes which can be recognized through petrographic observations and chemical mapping. In particular, there may not be a direct relation between an increase in P concentration and seasonal infiltration as has been found in some previous studies, especially if the source of this element is not the labile phosphate released through leaching during seasonal vegetation dieback in temperate climates.
Sub-Ice Sheet Environments in North Victoria Land during the Last Glacial Maximum
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-3176
Abstract: & & Subglacial calcite precipitates from Boggs Valley (71& sup& o& /sup& & #8217 S 161& sup& o& /sup& & #8217 E elevation 1,160 m asl., Northern Victoria Land, Antarctica), provided the first radiometrically-dated petrographic, geochemical and genomic evidence of thermogenic subglacial drainage events linked to subglacial eruptions during the Last Glacial Maximum (LGM). The crusts consist of two fabrics: i) a dirty (particulate-rich) microsparite, which marks catastrophic subglacial discharges of meltwater and a ii) dark columnar calcite that formed in pockets of basal melt. Synchrotron Radiation-based micro X-Ray fluorescence reveal that the dirty microsparite is S-rich, and embeds particulates characterized by high Manganese (Mn), Yttrium (Y) and Iron (Fe) concentrations. From previous work, we also know that the microsparite layers contain organic compounds, including amino acids, from which we extracted DNA fragments of microorganisms that lived in erse sub-Antarctic environments (Frisia et al., 2017). The elongated columnar calcites are characterized by the presence of Arsenic (As) associated with low concentrations of & Mn. Both elements suggest local anaerobic, chemolitothrophic metabolism. Columnar calcite becomes increasingly rich in S near the & #8220 discharge& #8221 layers. & & & & & Our preliminary interpretation is that during the LGM subglacial volcanism was crucial to sustain life in sub-ice sheet refugia by injecting both nutrients and erse microbes into the basal ecosystem. The otherwise nutrient-poor, anoxic subglacial environment sustained a population of chemolithotrophs, which may have also been & #8220 allochthonous& #8221 . & & & &
A 53 year seasonally resolved oxygen and carbon isotope record from a modern Gibraltar speleothem: Reconstructed drip water and relationship to local precipitation
Publisher: Elsevier BV
Date: 05-2008
Petrology and geochemistry of annually laminated stalagmites from an Alpine cave (Obir, Austria): Seasonal cave physiology
Publisher: Geological Society of London
Date: 2010
DOI: 10.1144/SP336.16
Origin and palaeoenvironmental significance of lamination in stalagmites from Katerloch Cave, Austria
Publisher: Wiley
Date: 25-01-2011
Environmental and site factors controlling the vertical distribution and radiocarbon ages of organic carbon in a sandy soil
Publisher: Springer Science and Business Media LLC
Date: 16-04-2013
Sulphate concentration in cave dripwater and speleothems: Long-term trends and overview of its significance as proxy for environmental processes and climate changes
Publisher: Elsevier BV
Date: 11-2015
Calcite Fabrics, Growth Mechanisms, and Environments of Formation in Speleothems from the Italian Alps and Southwestern Ireland
Publisher: Society for Sedimentary Geology
Date: 09-2000
DOI: 10.1306/022900701183
Stability and storage of soil organic carbon in a heavy-textured Karst soil from south-eastern Australia
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/SR13296
Abstract: 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 (30–100 cm), 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.
Hydroclimate of the Last Glacial Maximum and deglaciation in southern Australia’s arid margin interpreted from speleothem records (23–15 ka)
Publisher: Copernicus GmbH
Date: 21-12-2016
DOI: 10.5194/CP-2016-135
Abstract: Abstract. 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-latitude westerly winds on the region’s climate during this time period. In this study, two precisely-dated speleothem records for Mairs Cave, Flinders Ranges, are presented, providing a detailed terrestrial hydroclimatic record for the southern Australian drylands during 23–15 ka for the first time. Enhanced recharge to Mairs Cave is interpreted from the speleothem record by the activation of growth, physical flood layering and δ18O and δ13C minima. Periods of lowered recharge are indicated by isotopic enrichment, primarily affecting δ18O, argued to be driven by evaporation of shallow soil/epikarst water in this water-limited environment. A hydrological driver is supported by calcite fabric changes. The Mairs Cave record indicates that the Flinders Ranges were relatively wet during the LGM and early deglaciation, particularly over the interval 18.9–16 ka. This wetter phase ended abruptly with a shift to drier conditions at 15.8 ka. These findings are in agreement with the geomorphic archives for this region, as well as the timing of events in records from the broader Australasian region. The recharge phases identified in the Mairs Cave record are correlated with, but antiphase to, the position of the westerly winds interpreted from a marine core in the Great Australian Bight. The implication is that the mid-latitude westerlies are located further south during the period of enhanced recharge in the Mairs Cave record (18.9–16 ka), and conversely are located further north when greater aridity is interpreted in the speleothem record. A comparison with speleothem records from the northern Australasian region reveals that the availability of sub-tropical/tropical moisture is the most likely explanation driving enhanced recharge, with further lification of recharge occurring during the early half of Heinrich Stadial 1, possibly influenced by a more southerly-displaced Intertropical Convergence Zone (ITCZ). A rapid transition to aridity at 15.8 ka is consistent with a retraction of this tropical moisture source.
Sulfur fixation in wood mapped by synchrotron X-ray studies: Implications for environmental archives
Publisher: American Chemical Society (ACS)
Date: 04-02-2009
DOI: 10.1021/ES8029297
Abstract: There is a shortage of archives of sulfur that can be used to investigate industrial orvolcanic pollution in terrestrial catchments, but the role of S as a nutrient, coupled with sparse published evidence, suggests that trees are promising targets. We focused on two conifer species (Picea abies (L.) Karst and Abies alba Miller) from an Alpine site in NE Italy. Bulk analyses of Abies demonstrate that S concentrations were higher in the second half of the 20th century but with some high outliers possibly reflecting particulate impurities. X-ray synchrotron analyses confirmed the observed time trend, which is similar to that of a nearby stalagmite, and reflects an atmospheric pollution record mediated by storage in the soil and ecosystem. S and P were found to be localized in the inner cell wall (ca. 2 microm wide), local thickenings of which probably account for some outlying high values of S in synchrotron studies. S occurs as a mixture of oxidation states (0 to +0.5, +2, +5, and +6) which are consistent in space and time. The results indicate that wood older than a few years contains archive-quality S but that robust conclusions require multiple replicate analyses.
The Properties of Annually Laminated Stalagmites-A Global Synthesis
Publisher: American Geophysical Union (AGU)
Date: 19-04-2021
DOI: 10.1029/2020RG000722
Abstract: 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.
Synchrotron radiation applications to past volcanism archived in speleothems: An overview
Publisher: Elsevier BV
Date: 10-2008
Nano-scale investigation of co-precipitated subglacial calcite and opal, antarctica 
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-3547
Abstract: & & Calcite crusts from the Elephant Hill Moraine (EHM) (76& #176 '35& quot S & & #176 '05& quot E) collected during 1983-84 & were interpreted as formed in subglacial environments influenced by hydrothermalism (Faure et al., 1988). More recently, & sup& & /sup& U enrichment in these crusts was used to suggest that during the warm MIS 11 interglacial (ca. 400 ka), the ice sheet margin at the Wilkes Basin retreated about 700 km inland (Blackburn et al., 2020). Their & sup& & /sup& U data from separate analyses of pure calcite and pure opal crusts suggested that & #8220 connate seawater would impart marine signatures to subglacial waters& #8221 (Blackburn et al., 2020), with the former associated with massive melting during MIS 11. & However, robust U-series dating by Blackburn et al (2020) was only possible on pure end members of opal and calcite, whilst other EHM crusts did not yield reliable ages and were discarded. The inferred MIS11 ice-loss was then based on a model of & sup& & /sup& U accumulation and on those carbonate ages that fit their hypothesis that connate seawater influenced the subglacial environment.& & & & & & & & & Here, we investigated the nanostructure of EMH s les that yielded unreliable U-Th ages, which were too old to fit into the & sup& & /sup& U-based model of MIS11 connate seawater influencing subglacial waters. High-resolution transmission electron microscope images showed a complex history of precipitation, dissolution, re-precipitation, including the co-precipitation of nanocrystalline calcite and opal. Co-precipitation was documented by the inclusion of micrometre-scale opal spherules within calcite crystals whose lattice orientation does not change across the spherules and can be explained by the fluid being extremely enriched in silica. The calcite immediately surrounding the opal spherules was characterized by twins and likely a response to sub-ice sheet stress during their precipitation. The calcite-opal mixture partially replaced pre-existing calcite crystals, which appear broken, corroded and pre-date a final, pure calcite void-filling cement. Clearly, these EHM s les document several stages of crystallization, which imply repeated mobilization of chemical species. Preliminary Fluid Inclusion analyses of the crusts yielded a temperature of about 85& sup& o& /sup& C, which inferred that at one stage calcite precipitation may have been influenced by hydrothermalism associated with volcanism.& Our identification of complex crystallization histories for the Elephant Moraine subglacial carbonates opens up alternative formation hypotheses to that proposed by Blackburn et al. (2020) such as the existence of multiple sources of aqueous solutions. Consequently, it is fraught to infer that all the EMH formed from connate marine waters generated 400 ka without dating of multiple phases of calcite precipitation from each s le.& & & & & & & & & References: Blackburn, T. et al. 2020, Nature, 583 (7817), pp.554-559. Faure, G.& et al, 1988, Nature, 332(6162), pp.352-354.& &
Temperature and altitudinal influence on karst dripwater chemistry: Implications for regional-scale palaeoclimate reconstructions from speleothems
Publisher: Elsevier BV
Date: 03-2016
Regional climate variability and ecosystem responses to the last deglaciation in the northern hemisphere from stable isotope data and calcite fabrics in two northern Adriatic stalagmites
Publisher: Elsevier BV
Date: 07-2013
Continental carbonates growth pathways, fabrics and diagenesis
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-3170
Abstract: & & Continental carbonates are a repository of exceptional climate and environmental changes at scales from sub-annual to decadal to millennial. Their fabrics and chemistry encapsulate information about temperature and rainfall variability, volcanic eruptions, earthquakes, vegetation changes, as well as microbial interaction. Yet, fabric and chemical properties are influenced by the crystallization pathways and, crucially, growth mechanisms and diagenesis of the carbonate crystals. Here we present ex les from erse continental settings and discuss why fabrics are extremely important to determine the accuracy of preservation of a & #8220 rimary& #8221 signal.& & & & Most continental carbonate formation is driven by degassing. This is the case of cave carbonate deposits (speleothems), which allowed tremendous breakthrough in palaeoclimate science. Speleothems form in the dark, from drip waters poor in nutrients and organic compounds. Their most common fabric consist of columnar crystals. Nanoscale investigation shows that speleothem crystals have erse growth pathways, including particle attachment (Frisia et al., 2018). The distribution of climate-sensitive trace elements, thus, rather than following crystallographic sector zoning, follows & #8220 arallel growth layers& #8221 reflecting environmental changes. The critical parameter in growth process is the drip rate. By contrast, subglacial and cryogenic carbonates, which also grow in the dark and consist of columnar crystals, form in micro-phreatic environment where supersaturation is not attained by degassing, but by concentration of elements by slow freezing.& In this situation trace elements are incorporated following crystallographic faces and provide exceptional information of subglacial processes including volcanic eruptions (Frisia et al., 2017).& & & & Lacustrine, spring and fluvial carbonates grow at Earth& #8217 s surface, being exposed to Sun& #8217 s light. These carbonates& #8217 precipitation, similarly to speleothems, is promoted by degassing, but also by the presence of photosynthetic organisms and high substances organic interaction. Their fabrics are commonly characterized by micrite, which is rare in caves and in subglacial s les.& & & & Evaporitic lake (Great Salt Lake, GSL) and spring deposits described in Della Porta (2015) were observed by TEM. One typical microfabric is peloidal micrite. The GSL peloidal micrite consists of calcite nanocrystals, and the peloids are associated with aragonite and filaments. Spring deposits peloidal micrite also consists of nanocrystal aggregates surrounded by filaments.& & & & & Most speleothems and spring/lake carbonates document a phase of growth that involves nanocrystal aggregation, which we did not observe in the phreatic subglacial s les.& & & & Implications for palaeoenvironmental research: In speleothems, Ostwald ripening likely transforms nanoparticle aggregates into larger crystals. Critically, in speleothems, Ostwald ripening processes result in removal of some tracers, such as Si, associated to first growth phases, and preservation of those that we use to reconstruct palaeo hydrology. In lake and spring deposits it would seem that micrite preserves the original environmental data, because micrite means that the crystals were protected from ripening by the organic part of the deposit. In subglacial carbonates, growth appears to follow a classical ion attachment at growth sites, thus, their fabrics preserve pristine primary signals. & & & & & & & & & & & References:& & & & Della Porta, G. (2015) Geological Society, London, Special Publications 418, 17-68.& & & & Frisia, S. et al (2018) Earth-Science reviews 178, 68-91.& & & & Frisia, S.,& et al. (2017) Nature Communications 8.& & & & & & &
Holocene glacier history from alpine speleothems, Milchbach cave, Switzerland
Publisher: Elsevier BV
Date: 02-2011
Holocene climate variability in Sicily from a discontinuous stalagmite record and the Mesolithic to Neolithic transition
Publisher: Cambridge University Press (CUP)
Date: 11-2006
DOI: 10.1016/J.YQRES.2006.05.003
Abstract: Fabric and stable isotopic composition of a Holocene stalagmite (CR1) from a cave in northern Sicily record changes in paleorainfall in the early Holocene. High δ 13 C stable isotope values in the calcite deposited from ca. 8500 to ca. 7500 yr ago are interpreted as reflecting periods of high rainfall. The wet phase was interrupted by two periods of multi-century duration characterized by relatively cool and dry winters centered at ca. 8200 and ca. 7500 yr ago, highlighted by low δ 13 C and δ 18 O values. A high variability of δ 13 C values is recorded from ca. 7500 to ca. 6500 yr ago and indicates that the transition from a pluvial early Holocene to the present-day climate conditions was punctuated by decadal-scale periods of relatively dry winters. In northern Sicily, the traditional elements of the Neolithic appear at ca. 7700 yr ago. It is possible that changes in rainfall influenced the passage from hunter-gathering to farming and sheep-herding economies.
A compilation of Western European terrestrial records 60–8 ka BP: towards an understanding of latitudinal climatic gradients
Publisher: Elsevier BV
Date: 12-2014
Variations in atmospheric sulphate recorded in stalagmites by synchrotron micro-XRF and XANES analyses
Publisher: Elsevier BV
Date: 07-2005
Supplementary material to "Hydroclimate of the Last Glacial Maximum and deglaciation in southern Australia’s arid margin interpreted from speleothem records (23–15 ka)"
Publisher: Copernicus GmbH
Date: 21-12-2016
Unilateral vocal cord paralysis after surgical closure of a patent ductus arteriosus in extremely preterm infants
Publisher: Wiley
Date: 08-07-2017
DOI: 10.1111/JPC.13632
Abstract: Left vocal cord paralysis (LVCP) is variably reported post ligation of patent ductus arteriosus (PDA). Our objective was to determine the incidence of LVCP and identify predictive factors and associated morbidities in preterm infants post PDA ligation. This is a retrospective cohort study of infants less than 29 weeks gestational age from 2006 to 2014 who underwent PDA ligation. Infants with laryngeal symptoms underwent flexible fibreoptic nasopharyngolaryngoscopy to evaluate vocal cord function. We compared short- and long-term morbidities among infants with and without symptomatic LVCP. A total of 35 infants underwent PDA ligation in the study period, of which 11 infants (31%) developed symptomatic LVCP. Dysphonia was the presenting symptom in all neonates with LVCP and stridor was present in 46% (5/11) of them. The median (interquartile range) gestation (25 weeks (24-27) vs. 25 weeks (23-28)), birthweight (810 g (550-1180) vs. 825 g (550-1220)) and age at surgery (19 days (9-27) vs. 20 (5-69)) were similar in infants with and without LVCP, respectively. Infants with LVCP took significantly longer to reach suck feeds (128 vs. 90 days, P = <0.001), stayed longer in hospital (119 vs. 95 days, P = 0.01) and were more likely to go home on oxygen (73 vs. 27% P = 0.024). Neurodevelopmental outcomes were similar in the two groups. LVCP was noted in 31% of infants post PDA ligation and was associated with prolonged hospital stay, a longer time to reach suck feeds and a need for home oxygen. No predictive factors for development of LVCP were identified.
Recharge variability in Australia's southeast alpine region derived from cave monitoring and modern stalagmite δ18O records
Publisher: Elsevier BV
Date: 11-2022
Accurate dating of stalagmites from low seasonal contrast tropical Pacific climate using Sr 2D maps, fabrics and annual hydrological cycles
Publisher: Springer Science and Business Media LLC
Date: 26-01-2021
DOI: 10.1038/S41598-021-81941-X
Abstract: Tropical Pacific stalagmites are commonly affected by dating uncertainties because of their low U concentration and/or elevated initial 230 Th 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.
Last interglacial hydroclimate in the Italian Prealps reconstructed from speleothem multi-proxy records (Bigonda Cave, NE Italy)
Publisher: Elsevier BV
Date: 11-2021
NMR spectroscopic study of organic phosphate esters coprecipitated with calcite
Publisher: Elsevier BV
Date: 06-2016
Stalactites and Stalagmites
Publisher: Elsevier
Date: 2012
The influence of Antarctic subglacial volcanism on the global iron cycle during the Last Glacial Maximum
Publisher: Springer Science and Business Media LLC
Date: 09-06-2017
DOI: 10.1038/NCOMMS15425
Abstract: Marine sediment records suggest that episodes of major atmospheric CO 2 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 CO 2 sequestration from complementary Fe sources, such as the Antarctic ice sheet, due to the difficulty of locating and interrogating suitable archives that have the potential to preserve such information. Here we present petrographic, geochemical and microbial DNA evidence preserved in precisely dated subglacial calcites from close to the East Antarctic Ice-Sheet margin, which together suggest that volcanically-induced drainage of Fe-rich waters during the Last Glacial Maximum could have reached the Southern Ocean. Our results support a significant contribution of Antarctic volcanism to subglacial transport and delivery of nutrients with implications on ocean productivity at peak glacial conditions.
Climate forcings and their influence on Alpine history as reconstructed through the application of synchrotron based X-ray microfluorescence on layered stalagmites
Publisher: Wiley
Date: 05-2005
Tem and Aem Study of Pervasive, Multi-Step Dolomitization of the Upper Triassic Dolomia Principale (Northern Italy)
Publisher: Society for Sedimentary Geology
Date: 1993
Reconstructing hemispheric-scale climates from multiple stalagmite records
Publisher: Wiley
Date: 2006
DOI: 10.1002/JOC.1329
Hydroclimatic variability in Southeast Asia over the past two millennia
Publisher: Elsevier BV
Date: 11-2019
North Atlantic influences on climate conditions in East-Central Europe in the late Holocene reflected by flowstone compositions
Publisher: Elsevier BV
Date: 04-2019
A Dinosaur Tracksite in an Early Liassic Tidal Flat in Northern Italy: Paleoenvironmental Reconstruction from Sedimentology and Geochemistry
Publisher: Society for Sedimentary Geology
Date: 12-1997
DOI: 10.2307/3515410
Stable isotopes in caves over altitudinal gradients: Fractionation behaviour and inferences for speleothem sensitivity to climate change
Publisher: Copernicus GmbH
Date: 22-01-2013
DOI: 10.5194/CP-9-99-2013
Abstract: Abstract. 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 studying the isotopic composition of calcites from monitored caves located in steep altitudinal topography in the northern Italian Alps. These create a thermal gradient (3–12 °C) apt to study the effects of temperature on the speleothem isotope record. Our data indicate that the magnitude of oxygen isotope disequilibrium effects, calculated as an offset from the experimentally determined equilibrium, decreases with increased elevation (cooler temperatures) and faster drip rate. Carbon isotope values exhibit 13C enrichment at high altitudes (colder temperatures) and slow drip rates. The results obtained support modelling and laboratory cave analogue experiments that indicate temperature, drip rate, pCO2 and supersaturation are important factors controlling stable isotope fractionation, but also stress the significance of ventilation and evaporation in the cave environment. It is proposed that the effects on stable isotope ratios observed along the altitudinal gradient can be analogues for glacial to interglacial temperature changes in regions which were extensively glaciated in the past.
Holocene climate variability in north-eastern Italy: Potential influence of the NAO and solar activity recorded by speleothem data
Publisher: Copernicus GmbH
Date: 27-08-2012
Abstract: Abstract. 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 ka. Data from nine meteorological stations in Trentino show a significant influence of the North Atlantic Oscillation (NAO) on winter temperature and precipitation in the cave region. Spectral analysis of the stable isotope signals of ER 76 reveals significant peaks at periods of 110, 60–70, 40–50, 32–37 and around 25 a. Except for the cycle between 32 and 37 a all periodicities have corresponding peaks in power spectra of solar variability, and the 25-a cycle may correspond to NAO variability. This suggests that climate variability in northern Italy was influenced by both solar activity and the NAO during the Holocene. Six periods of warm winter climate in the cave region were identified. These are centred at 7.9, 7.4, 6.5, 5.5, 4.9 and 3.7 ka, and their duration ranges from 100 to 400 a. The two oldest warm phases coincide with the deposition of sapropel S1 in the Mediterranean Sea indicating that the climate in the cave region was influenced by this prominent pluvial phase in the Mediterranean area. For the younger warm phases it is difficult to establish a supra-regional climate pattern, and some of them may, thus, reflect regional climate variability. This highlights the complexity of regional and supra-regional scale Holocene climate patterns.
A guide to synchrotron hard X-ray fluorescence mapping of annually laminated stalagmites: Sample preparation, analysis and evaluation
Publisher: Elsevier BV
Date: 11-2021
Formation of calcite in the presence of dissolved organic matter: Partitioning, fabrics and fluorescence
Publisher: Elsevier BV
Date: 04-2020
Carbon mass-balance modelling and carbon isotope exchange processes in dynamic caves
Publisher: Elsevier BV
Date: 2011
Trace element distribution in annual stalagmite laminae mapped by micrometer-resolution X-ray fluorescence: Implications for incorporation of environmentally significant species
Publisher: Elsevier BV
Date: 03-2007
Carbon dioxide concentration in temperate climate caves and parent soils over an altitudinal gradient and its influence on speleothem growth and fabrics
Publisher: Wiley
Date: 03-02-2015
DOI: 10.1002/ESP.3706
Climate variability on the Adriatic seaboard during the last glacial inception and MIS 5c from Frasassi Cave stalagmite record
Publisher: Elsevier BV
Date: 12-2018
Sulphate partitioning into calcite: Experimental verification of pH control and application to seasonality in speleothems
Publisher: Elsevier BV
Date: 04-2018
The Neanderthal in the karst: First dating, morphometric, and paleogenetic data on the fossil skeleton from Altamura (Italy)
Publisher: Elsevier BV
Date: 05-2015
DOI: 10.1016/J.JHEVOL.2015.02.007
Abstract: 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 in idual, 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 ± 15 ka to 130.1 ± 1.9 ka. Thus, the skeleton from Altamura represents the most ancient Neanderthal from which endogenous DNA has ever been extracted.
Climate variability in the SE Alps of Italy over the past 17 000 years reconstructed from a stalagmite record
Publisher: Wiley
Date: 11-2005
Primary dolomite in the Late Triassic Travenanzes Formation, Dolomites, Northern Italy: Facies control and possible bacterial influence
Publisher: Wiley
Date: 25-09-2015
DOI: 10.1111/SED.12157
Tyrrhenian Holocene palaeoclimate trends from spelean serpulids
Publisher: Elsevier BV
Date: 09-2001
Crystallization pathways in stalagmites from the South Pacific: implications for fabrics and Sr uptake 
Publisher: Copernicus GmbH
Date: 28-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-13200
Abstract: & & Fabrics, trace element partitioning and stable isotope ratio fractionation into speleothem calcite depend on crystallization processes. We documented that in warm and wet tropical climate settings, high supersaturation and pH may shift from layer growth to nanoparticle/nanocrystal attachment. This suggests that both classical and non-classical growth mechanisms may be operating. We have observed that both non-classical amorphous calcium carbonate (ACC) nanoparticle or even nanocrystal attachment and spiral (classical) growth occur in calcite farmed in the caves of Atiu (Cook Island Archipelago).& Depending on localized shifts in SI& sub& cc& /sub& and pH, & #8220 impurities& #8221 may be preferentially incorporated as non-monomer species (non-classical) or monomer (classical) species. This gives rise to & #8220 random& #8221 lateral distribution of some trace elements that would otherwise be expected to follow the classical & #8220 sector zoning& #8221 pattern.& The & #8220 random& #8221 distribution is typical of porous columnar fabric, whilst the sector zoning distribution in Sr characterizes compact columnar calcite. In the porous columnar calcite fabric, the occurrence of non-classical ACC particle attachment also influences the stable oxygen isotope composition of its fluid inclusions, which is more negative than expected from dripwater (Global Meteoric Water Line) values. In the compact columnar fabric, there is not enough fluid inclusion water for measurements.& & & & When applied to Sr incorporation, our findings suggest that its uptake into speleothem calcite is a function of SI& sub& cc& /sub& and pH (which influence non-classical pathways) rather than growth rate, as already hypothesized by Wasylenki et al. (2005). However, by having in mind only a classical crystallization mechanism, SI& sub& cc& /sub& becomes a measure of growth rate. Consequently, the argument of Wasylenki et al. (2005) would not explain why Wassenburg et al. (2021) did not find a relation between Sr uptake and stalagmite growth rate. If SI& sub& cc& /sub& is taken as a measure of the transition from monomer-by-monomer to ACC nanoparticle attachment, then Sr uptake becomes dependent on processes that govern the transformation from ACC to calcite at the site of attachment. The presence of growth inhibitors (inorganic and organic) that may be incorporated as non-monomer species and observed in Atiu& #8217 s speleothems, may explain why Sr uptake may either depend on growth rate or not, as well as its lateral heterogeneous variability. Ultimately, in porous columnar fabric, Sr uptake is dictated by both non-classical pathways and the presence of growth inhibitors incorporated as non-monomers.& & & & References:& & & & Wassenburg, J.A., Scholz, D., Jochum, K.P., Cheng, H., Oster, J., Immenhauser, A., Richter, D.K., Haeger, T., Jamieson, R.A., Baldini, J.U.L. and Hoffmann, D., 2016. Determination of aragonite trace element distribution coefficients from speleothem calcite& #8211 aragonite transitions. & em& Geochimica et Cosmochimica Acta& /em& , & em& & /em& , pp.347-367.& & & & Wasylenki, L.E., Dove, P.M. and De Yoreo, J.J., 2005. Effects of temperature and transport conditions on calcite growth in the presence of Mg2+: Implications for paleothermometry. & em& Geochimica et Cosmochimica Acta& /em& , & em& & /em& (17), pp.4227-4236.& & & & & & &
Speleothems as sensitive recorders of volcanic eruptions – the Bronze Age Minoan eruption recorded in a stalagmite from Turkey
Publisher: Elsevier BV
Date: 04-2014
Phosphorus speciation in calcite speleothems determined from solid-state NMR spectroscopy
Publisher: Elsevier BV
Date: 02-2007
Holocene climate variability in Europe: Evidence from δ18O, textural and extension-rate variations in three speleothems
Publisher: Elsevier BV
Date: 07-1999
Investigating the hydrological significance of stalagmite geochemistry (Mg, Sr) using Sr isotope and particulate element records across the Late Glacial-to-Holocene transition
Publisher: Elsevier BV
Date: 02-2017
Chronology building using objective identification of annual signals in trace element profiles of stalagmites
Publisher: Elsevier BV
Date: 02-2009
Stalagmite carbon isotopes and dead carbon proportion (DCP) in a near-closed-system situation: An interplay between sulphuric and carbonic acid dissolution
Publisher: Elsevier BV
Date: 08-2017
Evidence for Holocene changes in Australian–Indonesian monsoon rainfall from stalagmite trace element and stable isotope ratios
Publisher: Elsevier BV
Date: 15-03-2010
Crystallization pathways in the Great Artesian Basin (Australia) spring mound carbonates: Implications for life signatures on Earth and beyond
Publisher: Wiley
Date: 25-03-2020
DOI: 10.1111/SED.12711
Controls on trace element (Sr–Mg) compositions of carbonate cave waters: implications for speleothem climatic records
Publisher: Elsevier BV
Date: 05-2000
Younger Dryas-Holocene temperature and rainfall history of southern Indonesia from δ18O in speleothem calcite and fluid inclusions
Publisher: Elsevier BV
Date: 06-2010
Annual trace element cycles in calcite-aragonite speleothems: evidence of drought in the western Mediterranean 1200-1100 yr BP
Publisher: Wiley
Date: 2005
DOI: 10.1002/JQS.943
Microstratigraphic logging of calcite fabrics in speleothems as tool for palaeoclimate studies
Publisher: University of South Florida Libraries
Date: 2015
Dolomite formation by nanocrystal aggregation in the dolomia principale of the brenta dolomites (Northern Italy)
Publisher: Rivista Italiana di Paleontologia e Stratigrafia (Research In Paleontology and Stratigraphy)
Date: 2019
Annual to sub-annual resolution of multiple trace-element trends in speleothems
Publisher: Geological Society of London
Date: 09-2001
Abstract: This study aims to establish evidence for the widespread existence of preserved high-resolution trace element variations in speleothems that may have climatic significance. Ion microprobe analysis of speleothems reveals that annual to sub-annual variations in element chemistry exist at five, shallow western European cave sites (Crag Cave, County Kerry and Ballynamintra, County Waterford, Ireland Uamh an Tartair, Sutherland, Scotland Grotte Pere-Noël, Belgium Grotta di Ernesto, NE Italy) with widely varying climatic, geomorphic and geological settings. The variations are not restricted to species (Mg, Sr and Ba) known to substitute directly for Ca in the calcite lattice, but include H, F, Na and P. Phosphorus (as phosphate) displays the greatest variability and may have the most significance as a proxy for the seasonal temperature cycle because of its role as a nutrient element. The technique allows estimation of growth rate of speleothems at any interval of interest, which is one of several possible uses in palaeoclimatology.
Effect of Nurse-Implemented Transitional Care for Chinese Individuals with Chronic Heart Failure in Hong Kong: A Randomized Controlled Trial
Publisher: Wiley
Date: 08-2015
DOI: 10.1111/JGS.13533
Aragonite-Calcite Relationships in Speleothems (Grotte De Clamouse, France): Environment, Fabrics, and Carbonate Geochemistry
Publisher: Society for Sedimentary Geology
Date: 09-2002
DOI: 10.1306/020702720687
Case-Based Web Learning Versus Face-to-Face Learning A Mixed-Method Study on University Nursing Students
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2016
Petrographical and geochemical changes in Bosnian stalagmites and their palaeo-environmental significance
Publisher: University of South Florida Libraries
Date: 2017
Biogeochemical cycling of sulphur in karst and transfer into speleothem archives at Grotta di Ernesto, Italy
Publisher: Springer Science and Business Media LLC
Date: 22-11-2012
Seasonal variations in Sr, Mg and P in modern speleothems (Grotta di Ernesto, Italy)
Publisher: Elsevier BV
Date: 06-2001
North Atlantic storm track changes during the Last Glacial Maximum recorded by Alpine speleothems
Publisher: Springer Science and Business Media LLC
Date: 27-02-2015
DOI: 10.1038/NCOMMS7344
Abstract: 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.
Late Holocene annual growth in three Alpine stalagmites records the influence of solar activity and the North Atlantic Oscillation on winter climate
Publisher: Elsevier BV
Date: 11-2003
Past fires and post-fire impacts reconstructed from a southwest Australian stalagmite
Publisher: Elsevier BV
Date: 05-2022
High-resolution sulphur isotope analysis of speleothem carbonate by secondary ionisation mass spectrometry
Publisher: Elsevier BV
Date: 03-2010
Increasing Australian-Indonesian monsoon rainfall linked to early Holocene sea-level rise
Publisher: Springer Science and Business Media LLC
Date: 02-08-2009
DOI: 10.1038/NGEO605
Holocene hydrological changes in Europe and the role of the North Atlantic ocean circulation from a speleothem perspective
Publisher: Elsevier BV
Date: 2021
Epikarst hydrology and implications for stalagmite capture of climate changes at Grotta di Ernesto (NE Italy): results from long-term monitoring
Publisher: Wiley
Date: 09-06-2010
DOI: 10.1002/HYP.7744
Evidence of thermophilisation and elevation-dependent warming during the Last Interglacial in the Italian Alps
Publisher: Springer Science and Business Media LLC
Date: 08-02-2018
DOI: 10.1038/S41598-018-21027-3
Abstract: 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 recorded by hydroclimate-sensitive archives, such as stalagmites and flowstones formed in caves. Understanding how hydroclimate manifests at high altitudes is important for predicting future water resources of many regions of Europe that rely on glaciers and snow accumulation. Using proxy data from three coeval speleothems (stalagmites and flowstone) from the Italian Alps, we reconstructed both the ecosystem and hydrological setting during the Last Interglacial (LIG) a warm period that may provide an analogue to a near-future climate scenario. Our speleothem proxy data, including calcite fabrics and the stable isotopes of calcite and fluid inclusions, indicate a +4.3 ± 1.6 °C temperature anomaly at ~2000 m a.s.l. for the peak LIG, with respect to present-day values (1961–1990). This anomaly is significantly higher than any low-altitude reconstructions for the LIG in Europe, implying elevation-dependent warming during the LIG. The enhanced warming at high altitudes must be accounted for when considering future climate adaption strategies in sensitive mountainous regions.
Definition of the anthropocene: A view from the underworld
Publisher: Geological Society of London
Date: 24-10-2014
DOI: 10.1144/SP395.7
Effect of aragonite to calcite transformation on the geochemistry and dating accuracy of speleothems. An example from Castañar Cave, Spain
Publisher: Elsevier BV
Date: 04-2019
Accurate dating of tropical South Pacific stalagmites using physical and chemical cycles
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-3656
Abstract: & & 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 & sup& & /sup& Th. This is the case of stalagmites from Atiu, in the Southern Cook Islands Archipelago, which potentially record shifts of the South Pacific Convergence Zone through time and their impact on droughts and floods. Here we constrain the U-series-based chronology using synchrotron & #181 XRF two-dimensional mapping of Sr concentrations coupled with growth laminae optical imaging constrained by in situ monitoring.& & & & Chronology involving annual laminae counting has, to date, been focused on settings where strong temperature seasonality favours the formation of annual geochemical hysical cycles. In Atiu caves temperature is constant throughout the year (mean & #8764 & #176 C), whereas precipitation exhibits a strong seasonality, with 70% of the mean Total Annual Rainfall (TAR = 1930& #177 mm/yr) occurring from December to May. However, during the drier season (June through November) rainfall amounts are still substantial, which can lead to missing dry seasons in the speleothem record. Moreover, a shallow depth of the caves (5 -10 m) and limited soil cover enhance fast transmission of rain signal into the caves, possibly resulting in the formation of sub-annual growth bands. Thus, the concentration variability of Sr and Mg alone are not sufficient to identify an annual signal.& & & & We integrated, in a multivariate analysis, high resolution (6& #181 m) variations in trace elements analysed by LA-ICP-MS, with optically visible growth bands and two-dimensional Sr-concentration laminae as identified through synchrotron-radiation-based micro XRF mapping. Cycles of [Mg], [Sr], [Na], [Ba] and [P] concentration were counted for three independent transects in a modern stalagmite (Pu17) from Pouatea Cave. This included semi-automated counting of peak positions on in idual elements, as well as on their principal components (PCA). The three independent analytical techniques produced 37 peak counting series, 20 of which were averaged and integrated into a single age model fitting into the uncertainty limits of U/Th dates. This master chronology was used to construct an age model that integrated laminae counting errors with the U/Th uncertainty. The average uncertainty of U& #8211 Th ages included in the age model is ca. 50%, whereas the initial lamina chronology has a maximum error of 15 years (4%), thus decreasing the uncertainty by at least 45%.& & & & Our yearly resolved chronology was then tested against the local rainfall record by using hydrologically sensitive elements Mg, Na and P. High correlation coefficients for each element corroborated the reliability of the age model, paving the way to reconstruct seasonally resolved records from trace element variations in these tropical speleothems.& &
Structure of V-ATPase from the mammalian brain
Publisher: American Association for the Advancement of Science (AAAS)
Date: 13-03-2020
Abstract: Vesicular- or vacuolar-type adenosine triphosphatases (V-ATPases) are ATP-hydrolysis–driven proton pumps. In neurons, V-ATPase activity generates a proton gradient across the membrane of synaptic vesicles so that neurotransmitters can be loaded into the vesicles. Abbas et al. developed a method to purify V-ATPase from rat brain and determined the structure of the entire complex by cryo–electron microscopy. Native mass spectrometry showed that the preparation was homogeneous and complemented structural studies by confirming the subunit composition. Three rotational states were resolved at better than 4-angstrom resolution, providing insight into the conformational changes that couple ATP hydrolysis to proton pumping. Science , this issue p. 1240
Modern speleothem oxygen isotope hydroclimate records in water-limited SE Australia
Publisher: Elsevier BV
Date: 02-2020
Evinosponges in the Triassic Esino Limestone (Southern Alps): documentation of early lithification and late diagenetic overprint
Publisher: Wiley
Date: 08-1989
An annually resolved stalagmite record of fire frequency for the last 250 years in south west Australia
Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-10651
Abstract: Stalagmites provide records of past changes in climate, vegetation, and surface events, which can be identified through variability in their chemical composition over time. This variability is the result of changes in surface environmental properties, which are reflected in the physical and chemical properties of the water that percolates into the cave, ultimately affecting the composition of the speleothem calcite. Wildfires have the potential to alter soil properties and soluble element concentrations. Consequently, stalagmite compositions have been shown to respond to increases in soil nutrients, trace metal concentrations, and changes in soil/karst bedrock hydraulic conductivity. It is, therefore, likely that stalagmites, and particularly those grown in shallow caves for which transmission of the surface signal is rapid, capture the environmental effects of wildfires in their chemical and physical properties.We analysed a stalagmite from a shallow cave in a region known to be affected by wildfires in south-west Western Australia. Fire proxies were assessed using a multi-proxy approach. This includes water isotopes via stable-isotope ratio mass spectrometry and trace element analyses via synchrotron X-ray fluorescence microscopy and laser ablation inductively coupled plasma mass spectrometry. This approach shows that the timing of known fire events coincided with a multi-proxy response in stalagmite chemistry, including increased concentrations of phosphorus, copper, aluminium, lead, and zinc, which are interpreted to be derived from leaching of ash from burned vegetation above the cave. We also identified lower and less variable peaks in phosphorus concentrations during the pre-colonisation period, suggesting that Indigenous land management resulted in more frequent but low intensity burning. This contrasted with less frequent but more intense fires associated with post-colonisation land-management. A particularly large paleo-fire identified in 1897 appears to coincide with a peak in & #120575 O, interpreted to have resulted from evaporation of sub-surface water during the heat of the fire. This large fire was preceded by a multi-decadal dry period identified by trace element proxies. The intensity of the 1897 fire was then exacerbated by the combination of a multi-decadal drought and a transition away from cultural burning practices by Indigenous Australians, which resulted in build-up of vegetation and dry combustible material on the forest floor.This research is a world-first demonstration of fire events recorded in stalagmites and shows their potential to provide accurate records of both fire frequency intervals and changes in climate. Further records of past fire events from stalagmites will help to understand how past fire regimes have varied with climate, land-use change and colonisation, and will help to better guide land management practices in the future.
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