API src

Found 197 results.

Carbon isotopes in OIB Mantle source

Other

Horizontal-to-Vertical Spectral Ratios (HVSR) of NW Italy seismic stations elaborated during the "FOCUS-HVNEA" NOA-ILGE project

This data set consists of Horizontal-to-Vertical Spectral Ratios (HVSR) resulting from the application of the software package HVNEA (HV Noise and Earthquake Automatic Analysis) with the aim of comparing them with those resulting from the application of another method, namely STATION (Seismic sTATion and sIte amplificatiON). The results, relative to more than 24,000 HVSR, derive from the processing of 700,000 seismograms recorded over different time periods by 8 stations of the networks IV (Italian Seismic Network), GU (Regional Seismic Network of North Western Italy) and GV (Mobile RSNI). To compare the results of the two methods as accurately as possible, the waveforms were subjected to the same preprocessing already used to elaborate the results stored in the STATION database. To this end, the methodological workflow applied with HVNEA for station IV.MURB involved the selection of segments from continuous recordings for each event reported in the INGV catalogue located within a radius of 120 kilometres from the station. Starting from the automatically picked S-wave onsets, 12-second windows were then extracted and used for the analysis of earthquake recordings. Regarding the noise analysis, it should be noted that STATION again considers 12-second windows selected before the P-wave onset, while HVNEA requires the use of a signal window of at least 60 seconds. A window of 3,600 seconds was used for the analysis. The comparison of the HVSR was performed in the frequency band 0.1–15 Hz. All analysed curves, for both earthquake and noise recordings, show generally similar shapes and identify significant peaks in correspondence of the same frequency ranges, although the amplitudes obtained with STATION are systematically higher than those obtained with HVNEA. To obtain a quantitative comparison, various statistical metrics commonly used to measure the discrepancy between data sets were applied, namely the Mean Squared Error, the Mean Absolute Error and the Pearson Correlation Coefficient. This publication results from work conducted under the transnational access/national open access action at the Site effects Laboratory – INGV L’Aquila supported by WP3 ILGE–MEET project, PNRR–EU Next Generation Europe program, MUR grant number D53C22001400005.

Intercalibration of the intra-laboratory 40Ar/39Ar reference material Drachenfels sanidine

The dataset contains full 40Ar/39Ar geochronological data completed by multi-collector noble-gas mass spectrometry using the laser total fusion technique on sanidine separated from the Drachenfels trachyte (Drachenfels, Bad Godesberg, Germany). The Drachenfels sanidine represents a useful intra-laboratory reference material for laser work. The purpose of the dataset is to share updated intercalibration data for the intra-laboratory Drachenfels sanidine, relative to the widespread fluence monitors Alder Creek sanidine and Fish Canyon sanidine, that can be used in future 40Ar/39Ar geochronological studies. W. McIntosh (New Mexico Geochronology Research Laboratory, Socorro, NM), P. Renne (Berkeley Geochronology Center, Berkeley, CA) and J.R. Wijbrans (Vrije Universiteit Amsterdam, NL) kindly provided splits of FCs, ACs and DRA1, respectively. The Ar laserprobe facility was realized with the financial support of CNR. The CO2 laser system was acquired within the PNRR – Mission 4, “Education and Research” - Component 2, “From research to business” - Investment line 3.1, “Fund for the creation of an integrated system of research and innovation infrastructures” - Project IR0000025 MEET.

The noble gas isotopic composition of the upper mantle in non-arc oceanic settings: Inferences from fluid inclusion studies

OIB localities (e.g., Tristan, Samoa) have been considered ideal natural laboratories for studying mantle heterogeneity. Indeed, Sr, Nd, and Pb isotopes of lavas collected from OIB systems have provided insights into the existence of distinct mantle reservoirs, the origins of which are closely related to local tectonic processes: DMM, HIMU, EM1, and EM2. In this context, we aim to investigate the isotopic composition of noble gases in fluid inclusions trapped in xenoliths and lavas from Samoa and Tristan islands, two well-known enriched mantle (EM) localities. Our goal is to evaluate the role of noble gas cycling and active tectonic processes on the composition of the upper mantle. Our results show that CO2 is the most abundant volatile in all samples (lavas and xenoliths) from both localities. The 4He/20Ne ratio in most samples is lower than 150, suggesting the presence of atmospheric components in the fluid inclusions. This is further confirmed by the relatively low 40Ar/36Ar ratios, particularly in Tristan samples, which show values below 360. It is worth noting that the Samoa sample exhibits a 40Ar/36Ar ratio of 1000.4, the highest of the dataset. The Rc/Ra values (3He/4He corrected for atmospheric contamination) observed in the Samoa samples align with the Ar ratios mentioned above, as the 3He/4He ratio is the highest reported (13.32Ra). This is above the MORB range, indicating a contribution from lower mantle fluids, likely derived from the Samoan hotspot. In contrast, Tristan samples exhibit low Rc/Ra values, with an average of 5.12Ra. These low helium ratios suggest the presence of a more radiogenic, 4He-rich mantle. The low helium ratios may be related to the EM nature of the mantle. Previous studies in the Canary Islands have shown a decrease in 3He/4He ratios in the eastern part of the archipelago, where EM components have been identified (Hoernle et al., 1993; Simonsen et al., 2001; Day and Hilton, 2011, 2021; Sandoval-Velasquez et al., 2021). However, it is confirmed that an EM component can show a wide range of variation for the 3He/4He ratio, ranging from low values of 5-6Ra to values beyond the typical MORB range, which overlaps (and complicates the distinction) with other OIB contexts with HIMU signature. This publication results from work conducted under the transnational access/national open access action at INGV-Palermo- Noble gas laboratory supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.

∂13C data of picrite rock samples from St Helena Island (South Atlantic Ocean)

Other

Cathodoluminescence zoning images of Lower El Cajete quartz and sanidine crystals, Valles Caldera, New Mexico, USA

The Valles Caldera, New Mexico, USA was created by two caldera-forming eruptions at ~1.6 and ~1.1 Myr. Since then, post-caldera activity has consisted of lava domes, lava flows, large explosive phases, and a hydrothermal system active today. Possibly the youngest eruption sequence, El Cajete, was emplaced 74.4 ± 1.3 ka (Zimmerer et al., 2016) and began with pyroclastic surges, followed by pyroclastic density currents (PDCs) and pumice-rich Plinian pyroclastic fall (Self et al., 1988). The objective of this project was to characterize crystal grains from the early El Cajete sequence, in terms of morphology and textures, using scanning electron microscopy (SEM). The early El Cajete differs from the later part of the sequence in its greater stratigraphic and lithologic complexity, having been formed from not only pyroclastic fall (like the later El Cajete) but also surge beds and PDCs. This dataset was collected under the national open access action at Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Pisa SEM/EDS facility supported by WP3 ILGE – MEET project, PNRR – EU Next Generation Europe program, MUR grant number D53C22001400005. This allowed me to obtain the present dataset of 31 cathodoluminescence (CL) images of 30 quartz crystals and one sanidine crystal.

Crystal Size Distribution Analyses of Isothermal Deformation Experiments

In this work we aimed to investigate and quantify the relative importance of dynamic conditions (e.g., stirring in a Concentric Cylinder apparatus) on the crystallization kinetics of basaltic magmas (Stromboli). This was achieved by observing the final textures of the samples, analysing the resulting SEM images, and finally relating the resulting parameters to specific growth and nucleation rates. The dataset is made of: 1) A folder called "SEM Images" with two sub-folders inside, representative of the two experiments carried out, called "CG1" and "CG2.3" 2) An Excel file, consisting in 4 data sheets, where all results of image analysis are included, divided in sections. The sheets are also available in CSV format. This publication results from work conducted under the transnational access/national open access action at High Pressure - High Temperature Laboratory (HPHT Lab), Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.

Digital Elevation Models and Time-Lapse Imagery from Analogue Experiments on the Interaction between Magma Injection and Rainfall-Driven Surface Processes

This dataset documents a series of analogue experiments designed to investigate the coupled evolution of magma-driven surface uplift and rainfall-driven geomorphic processes. Seven controlled laboratory experiments were conducted, each combining shallow intrusion of a magma analogue with imposed rainfall of varying intensity, in order to systematically explore the role of surface processes under different forcing conditions. The experimental setup consists of a rigid Plexiglas container filled with a water-saturated granular mixture formulated to reproduce brittle crustal behaviour under wet conditions. Magmatic intrusion was simulated by injecting a fixed volume (360 cm³) of low-viscosity polyglycerine through a basal inlet at three distinct injection rates, while surface processes were imposed using an overhead rainfall system delivering three different rainfall intensities. Topographic evolution during each experiment was monitored using a structured-light laser scanner (Artec Leo). For every model run, six Digital Elevation Models (DEMs) were generated at synchronised stages corresponding to 0%, 20%, 40%, 60%, 80% and 100% of the injected volume, yielding a total of 42 DEMs. Raw scans were processed through a triangulated irregular network (TIN) meshing workflow and subsequently rasterised to GeoTIFF format without additional post-processing, in order to preserve the original topographic signal. In parallel, time-lapse photographic documentation was acquired throughout each experiment using a digital camera, providing a complementary visual record of dome growth, surface incision and sediment redistribution. The dataset is organised into two main components: (i) high-resolution topographic datasets (DEMs) and (ii) time-indexed photographic sequences, both linked to the temporal evolution of each experiment. Quality control procedures include scanner calibration prior to acquisition, verification of mesh consistency and raster resolution, and a closed-system experimental design ensuring mass conservation. All data are distributed in their original formats and accompanied by detailed documentation describing experimental procedures, data processing workflows, and file organisation, enabling reproducibility and reuse in quantitative analyses of coupled magmatic and surface processes. This publication results from work conducted under the transnational access/national open access action at University Roma Tre, Laboratory of Experimental Tectonics (LET) supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.

High resolution age model from sedimentary collected along the southwestern Svalbard margin

This dataset includes updated versions of high-resolution age models derived from six sedimentary cores collected from the southwestern Svalbard margin. The dataset presented here represents a refinement of a previous version (Caricchi et al., 2020; 2022), achieved through correlation of the stratigraphic trends of the ARM/k parameter with the GICC05modelext timescale and the NGRIP record (Rasmussen et al., 2014). Additional refinement was obtained from newly acquired and recalibrated radiometric data, as well as from improved lithological constraints. The dataset enables the calculation of sedimentation rates during glacial and interglacial periods and during short-lived, widespread meltwater pulses and Heinrich-like events, thereby allowing the reconstruction of ice-sheet instability and meltwater events along the Svalbard–Barents Sea margin over the last 60,000 years.

New and compiled palaeomagnetic data from western Ross Sea (Antarctica) spanning the last ca. 10 ka

This dataset includes both original and previously published paleomagnetic data. The new data refer to a marine sediment sequence (ANTA02-AV43 core) collected in the in Wood Bay, located along the coast of Victoria Land, within the western Ross Sea (Antarctica) and spanning the last ca. 10 ka. The formerly published paleomagnetic data from coeval sediment cores refer to the from the RS15‐GC57 core of Truax et al. (2025) collected in the adjacent Robertson Bay, and from the PC18 and PC19 cores of Macrì et al. (2005), recovered from the continental rise of the Wilkes Land basin offshore the coast of East Antarctica. The data from these two latter cores were relocated to the location of the ANTA02-AV43 core with the Noel and Batt (1990) method. The estimated age of the formerly published dataset has been re-evaluated after correlation of paleomagnetic trends with the ANTA02-AV43 core and prediction of geomagnetic variation at the ANTA02-AV43 site according to the CALS10k.2 model of Constable et al. (2016). We then combined the new ANTA02-AV43 dataset with existing Holocene records from sediment cores of comparable resolution (PC18 and PC19) to develop the paleomagnetic “HOLOANTA” stack. This composite record averages paleomagnetic data over the last 10,000 years in 200-year intervals. It includes relative paleointensity (RPI) as well as paleomagnetic inclination and declination data, providing a robust regional Holocene RPI curve alongside directional secular variation (PSV) trends.

1 2 3 4 518 19 20