Italian Antarctic Data Center
GEOCHEMISTRY
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Here we present the snow pits collected along the international EAIIST project traverse, which took place in 2019-2020 Antarctic Campaign. We report the number of snow pits collected, the depth of the samplings and their geographic information.
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Here we present the surface snow samples collected along the international EAIIST project traverse, which took place in 2019-2020 Antarctic Campaign. We report the number of surface samples (upper 10 cm and integrated 1m samples) collected and their geographic information.
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Below the results obtained by the HOT ANTARCTICA project are presented. Results regarding geochemistry of crustal melts Main results obtained by the most prominent samples are described separately for each of the investigated terranes (Napier Complex, Lützow Holm Complex, Rauer Islands and Schrimacher Hills). The methodology employed during the work is also listed below: 1) Samples interrogated in this project were previously collected from Napier Complex (provided by the collaboration with Prof. Simon Harley, University of Edinburgh), Lützow Holm Complex (provided by the collaboration with Prof. Satish-Kumar, University of Niigata), Rauer Islands (provided by the collaboration with Prof. Simon Harley, University of Edinburgh and in collaboration with Zhao Liu, Northwest University ,China) and Schrimacher Hills (provided by the Museo Nazionale dell’Antartide, Siena, Italy). 2) Microstructural and petrographic study were done in all samples to identify equilibrium assemblages, melting reaction microstructures and occurrence of nanogranitoids (i.e. crystallized inclusions), melt and fluid inclusions. 3) Microstructural characterization of inclusions using Field Emission-Scanning Electron Microscope (FE-SEM) analyses were done: i) to identify the submicrometric phases within nanogranitoids and ii) to verify the homogeneity of remelted nanogranites and preserved glassy melt inclusions. 4) Experimental remelting of crystallized melt inclusions was performed to overcome the problem of MI decrepitation and volatile loss. The remelting of nanogranitoids was performed at high pressure with a piston cylinder apparatus using a QUICKpress piston cylinder apparatus produced by Depths of the Earth (installed at the Dipartimento di Geoscienze, UniPd). 5) Analysis of the major and trace elements contents of melt inclusions was carried out using i) an electron microprobe at the at University of Milan and ii) a LAICPMS at University of Perugia. 6) Thermodynamic modeling of anatectic conditions: the evaluation of P-T-X parameters and of P-T paths in the different geologic contexts were carried out using the software Perple_X. 7) Micro-Raman spectroscopy: characterization of fluid inclusions coexisting with melt inclusions was done using a HORIBA LabRam HR (high resolution) Raman microspectrometer at the University of Pavia. 8) Cross-comparison of data: during the development of this research project all collected data were analyzed by cross-comparing the information from the different geological contexts, with the aim to highlight similarities and differences. 9) Data discussion and evaluation: all data was analyzed and discussed in tight collaboration with the researchers involved in this project. 10) Synthesis and dissemination of results: dissemination of results was done with oral and poster presentations in several international conferences (see list on the appropriate section - Atti). Presentations include invited keynote presentations by the PI, Bruna Borges Carvalho at Goldschmidt (France, 2023) and Hutton Symposium (Italy, 2023). Invited seminars were also given in several important universities around the world [University of Bern, Switzerland; University of Cambridge, UK; University of Niigata, University of Kyoto, Japan]. Furthermore, a total of two research papers have been published in journals of high impact factor, and other two articles are in preparation. Here we also provide mineral, geochemical and geochronological data of studied areas at Rundvagshetta and Rauer Islands. Preprinted versions of two published article where the data is explained are also provided. Carvalho, B.B., Bartoli, O., Cesare, B., Satish-Kumar, M., Petrelli, M., Kawakami, T., Hokada, T., Gilio, M. (2023). Revealing the link between A-type granites and hottest melts from residual metasedimentary crust. Geology 51, 845-849. https://doi.org/10.1130/G51097.1 Liu, Z., Carvalho, B.B., Li, W., Tong, L., Bartoli, O., Li, C., Chen, L., ,Yan, Q, Wu, H. 2023. Into the high to ultrahigh temperature melting of Earth’s crust: Investigations of melt and fluid inclusions within Mg–rich metapelitic granulites from the Mather Peninsula, East Antarctica. Journal of Petrology 64, egad051. https://doi.org/10.1093/petrology/egad051 Results regarding petrology and geochronology of granulites In northern Victoria Land, the presence of two contrasting P-T paths suggests the possibility that high-grade complexes could have experienced a different metamorphic evolution both in space and time. Geochronological data of the Granite Harbour Intrusives support a prolonged magmatic activity (540-480 Ma), with multiple igneous pulses. This could imply the existence of magmatic underplating triggering the development of monometamorphic granulites during the Ross Orogeny. On the other hand, structural and PT evolution suggest the presence of a polymetamorphic granulitic belt that could be remnant of older orogeny as the Panafrican (ca. 600-500 Ma) (Lombardo et al., 1987; Palmeri, 1997; Talarico and Castelli, 1995). In order to discriminate mono- from poly-metamorphic evolution, metasedimentary granulite complex from the Deep Freeze Range has been investigated. Among all available granulite samples, a detailed petrographical study has been conducted to select the most representative and suitable HT granulite-facies rocks: four samples have been individuated for petrological and geochronological analyses (Opx-Grt and >30 µm Zrn/Mnz bearing), fifteen for geochemistry (absence of leucosome). In the Deep Freeze Range, HT granulites consist of Grt-Opx±Bt±Crd±Spl±Crn gneisses characterized by the presence of numerous Opx±Grt leucocratic segregations. Geochemical results confirm that analyzed granulite protholites have sedimentary origin, being comparable to Post Archean Australian Shale (PAAS; Taylor and McLennan, 1985), and they have been deposited in an orogenic setting (active continental margin). Petrographical, microstructural and mineral chemistry analyses show a metamorphic evolution including three different stages: Pl-Grt1-Spl-Crn-Ilm medium-P granulite facies (M1), Qtz-Pl-Opx-Grt1-Crd-Ilm-Kfs low-P granulite facies (M2), and Qtz-Pl-Grt2-Kfs-Bt-Ath low-P amphibolite (M3). Preliminary petrological results indicate that evolving metamorphic parageneses describe an initial isothermal decompression (exhumation event) followed by isobaric cooling; further thermodynamic modeling by software Perple_X will allow to better define P-T-X conditions. Geochronological studies involved the observation and analysis of monazites and zircons on four selected granulite thin sections. Investigations included X-ray mapping carried out under the electron microscope, CL-BSE imaging (zircons), and trace element analysis and U-Pb dating using LA-ICP-MS. Acquired data are still under review and will have a fundamental role in the reconstruction of the P-T-t path, thus making it possible to discriminate between mono- and poly-metamorphic hypotheses. References Lombardo et al 1987. Memorie della Società Geologica Italiana 33, 99-130. Palmeri R. 1997. Lithos 42, 47-66. Talarico and Castelli D. 1995. Precamb. Res. 75, 157-174. Taylor and McLennan S.M. 1985. Blackwell, Oxford, 312 p.
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Here we present the firn cores collected along the international EAIIST project traverse, which took place in 2019-2020 Antarctic Campaign. We report the number of firn cores collected, the depth of the samplings and their geographic information.
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The IPICS-2kyr-Italia project, through multiple perforations in the Antarctic ice sheet, aims to provide new data on climatic variability over the last 2000 years. The ice caps are natural archives of the Earth's climatic and environmental history. The extraction of snow and ice cores have taken place during the summer Antarctic campaign (November 2013 - January 2014). The drilling site GV7 (70°41'S, 158°52'E; 1950 m), was chosen for the high snow accumulation and was located about 500 km from Mario Zucchelli Station.
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The SENECA project aims to provide first evaluations of gas concentrations and emissions from permafrost and/or thawing shallow strata and to derive a first estimate of the CO2 and CH4 emission at Southern Polar Hemisphere. The obtained results can also be used to assess uncovered new problems and opportunities, such as how the Antarctica environment can increase to permanent and temporal scale the global temperatures. The project is organized in four major tasks: (1) soil gas content and origin; (2) CO2 and CH4 degassing output; (3) geophysics exploration and petrographic characterization of the soils; (4) seasonal trend of CO2 soil concentration. Geochemical data: The geochemical dataset includes: Soil gas sampling/flux measurements and GasPRO CO2 monitoring probes Soil gas surveying consists in collecting gas samples from the active layer zone to measure the concentrations of some gaseous species in the soil pores. To avoid the major influence of meteorological variables, samples are collected inserting a steel probe vertically in the soil to a depth from 0.2 m to 0.6 m, depending by the thickness of the active layer. Soil gas samples are taken from the probe by using a 60 cc plastic syringe and stored in a 15 ml glass vials. The collected gas samples have been analyzed in Scott Base lab with a chromatographer (CP 4900 by Varian) to define the concentrations of the following gaseous species: He, Ne, H2, O2, N2, CH4, C2H2, C2H4, C2H6, CO2, H2S. Radon (222Rn) and Thoron (220Rn) have been measured directly in the field using Durridge RAD7 instrument performing three/four measurements with 5-minute integration time. A total number of 226 samples were collected in this first expedition. Measurements of exhalation flux of CO2 and CH4 from the soil into the atmosphere have been conducted using the West System (West Systems TM) accumulation static closed-chamber method. Continuous monitoring of CO2 concentrations in active layer bottom was started with the deployment of GasPro CO2 Monitoring Probe designed to measure temperature, pressure and CO2 concentration in the unsaturated soil horizon. CO2 concentration is measured via a Non-Dispersive Infra-Red (NDIR) sensor (model IRC‐A1 Alphasense). The probes are equipped with four batteries and a small solar panel that should last for 10 to 12 months (depending on the outside temperature), collecting 1 measurement/hour. Water and permafrost sampling We sampled shallow waters among all streams, ponds and lakes in the studied areas. Physical-chemical parameters such as water temperature, pH, redox potential (Eh), electrical conductivity and alkalinity were determined in situ. Water samples were collected and stored in high-density polyethene flacons for laboratory analysis in the following amount: 2 flacons of 50ml for major anions and cations 1 flacon of 50ml for minor and trace elements 1 flacon of 100ml for isotopic analyses 1 serum glass bottle of 155ml for dissolved gas in the water. Major anions and cations were sampled on filtered and filtered and acidified samples, respectively. Minor and trace elements were collected on filtered and acidified samples. An unfiltered sample was collected for the determination of stable isotope analyses (δ18O, δD). The analysis of the chemical composition of dissolved gases (He, Ne, H2, O2, N2, CH4, CO2), extracted from water samples collected in serum glass bottles and sealed by gas-tight rubber plugs according to the method of Capasso and Inguaggiato (1998), was carried out in the Scott Base Laboratory by using a Agilent 4900 CP Micro-gas chromatograph equipped with two TCDs and Ar as carrier gas. Dissolved gas composition (expressed in mmol/L at STP) was calculated from the composition of the exsolved gas phase based on the solubility coefficient of each gas compound (Whitfield, 1978). Analytical error was <5%. A total number of 31 water samples were collected in this expedition. In addition, 33 permafrost samples were collected. These samples were sampled by hitting the permafrost with a hammer and chisel and collecting the small pieces of still frozen permafrost in a serum glass bottles of 155 ml. The bottle was sealed and vacuum-packed by removing the air inside it using a needle and syringe. Once the permafrost samples were defrosted, the gas content in the bottles were measured (He, Ne, H2, O2, N2, CH4, CO2). These measurements were performed directly at Scott Base using the Agilent 4900 CP Micro-gas chromatograph.
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The IPICS-2kyr-Italia project, through multiple perforations in the Antarctic ice sheet, aims to provide new data on climatic variability over the last 2000 years. The ice caps of the polar caps are valuable natural archives of the Earth's climatic and environmental history. The extraction of the snow and ice cores have taken place during the summer campaign of the Italian expedition to Antarctica 2013/2014. The drilling site GV7 (70°41'S, 158°52'E; 1950 m), chosen for the high snow accumulation, is about 500 km from Mario Zucchelli Station. Drill up to 250 - 500m. Core samples will be studied by chemical, isotopic and physical analyses of the dust and gases contained in the ice. It will thus be possible to reconstruct the evolution of temperatures, the composition of the atmosphere and atmospheric circulation, the frequency of volcanic eruptions and the air pollution produced by human activities over the last millennium with considerable temporal detail.
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Core samples of the drilling site GV7 are studied by chemical, isotopic and physical analyses of the dust and gases contained in the ice. It will thus be possible to reconstruct the evolution of temperatures, the composition of the atmosphere and atmospheric circulation, the frequency of volcanic eruptions and the air pollution produced by human activities over the last millennium with considerable temporal detail. Analysis: isotopic composition, oxygen and hydrogen content (UniVe and UniPR); tephra (ENEA); wind power (UniMib); trace metals (CNR); ion content chemistry (UniFi).
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The RESTORE project is dedicated to the development of portable robotic technologies with the capability to perform multi-disciplinary multi-parametric 3-D monitoring of marine environment. Its primary focus lies in examining critical areas such as the air-sea-ice and water-sediment interfaces in Antarctica. This endeavour aims to support various research aspects, including the study of microbial ecology and DNA tracing, as well as the investigation of Antarctic geology, particularly the dynamics surrounding glaciers and ice-covered coastal regions. Furthermore, RESTORE is committed to scrutinising the impacts of climate change on the Antarctic atmosphere and the exchanges that occur between the sea and air. The comprehensive dataset collected during RESTORE will provide researchers with a holistic perspective on an extreme and remote environment such as Antarctica, facilitating the interpretation of atmospheric and oceanic dynamics at the interface zones and, the 3D mapping of the underwater environment and the physical characterisation of the sampled region.