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Carbon isotopes in OIB Mantle source

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Results from analogue inversion experiments of extensional basins parallel and oblique to their boundaries with inferences from the European eastern Southern Alps

This image dataset contains results (original top-view and cross-section photographs) obtained from a series of 12 crustal-scale physical analogue modelling experiments performed in the Tectonic Modelling Laboratory (TecLab) at Utrecht University. We employed analogue modelling to study the inversion of extensional basins that are parallel and oblique to their boundaries. The key parameters of this study are: (i) the obliquity angle (0°, 10° or 20°) of shortening in relation to the strike of the initial rift structures; (ii) the basal décollement rheology; and (iii) the rheology of the basin fill. All analogue experiments are rectangular, 2 cm thick and consist of deformable brittle or brittle–ductile layers. Deformable parts in entirely brittle models are made of a homogeneous layer of quartz sand for the initial, non-stretched, pre-rift model crust. The subsequently resulting grabens are filled with syn- to post-extensional sediments of quartz sand, feldspar sand, or glass beads. Variations to these setups entail either a brittle layer of glass beads at the base of the above described brittle crust, or, for brittle-ductile models, a viscous layer of PDMS silicone putty with fillers. All experiments are built on one fixed above two mobile plastic sheets, their transition is pre-defining velocity discontinuities (VDs). In a first stage, deformation is induced in all models by two electric motors pulling the two mobile plastic sheets in opposite directions parallel to the backstop. These sheets are then fixed once the extensional phase is finished. VDs positioned both orthogonally and obliquely with respect to the backstop allow graben structures to form at angles of 0°, 10° and 20° to the subsequent shortening direction. In a second stage, a rigid backstop moves into the model to create compressive deformation within the entirely brittle or brittle-ductile layers. Top-view photographs were taken at regular time intervals throughout each experiment (see below for details). Cross-section photographs were taken at the end of each experiment. Therefore, the top-view photographs enable surface deformation to be tracked and analysed through time and space, while the cross-sections demonstrate the overall vertical deformation of each model. For more details about the models, see Sieberer et al. (2023). The properties of the materials used are described in Sieberer et al. (2023), Klinkmüller et al. (2016) and Willingshofer et al. (2018). All models are scaled according to the principles of geometric, rheological, and kinematic similarity between nature and models (Hubbert, 1937; Weijermars & Schmeling, 1986).

Naturschutzgebiete nach Aktionsplan Ostseeschutz 2030

Die Gebietsabgrenzungen der Naturschutzgebiete (NSG) im Aktionsplan Ostseeschutz 2030 gemäß der Verordnungen vom 11.03.2026 werden umgehend in den Gesamt-Datenbestand der Naturschutzgebiete aufgenommen. Bis dahin ist eine kartografische Darstellung nicht möglich. Der Download der Daten ist hier möglich. Die Abgrenzungen sind die linienhaften Verbindungen zwischen den Stützpunkten gemäß der Verordnungen.

Satellitenpositionierungsdienst SAPOS

Der Satellitenpositionierungsdienst SAPOS stellt das amtliche Lagebezugssystem für die Bundesrepublik Deutschland (Koordinatenreferenzsystem ETRS89_UTM32 (Bezugssystem ETRS89 mit Abbildungsvorschrift UTM, EPSG-Code 25832, frühere Bezeichnung: Lagestatus 310)) bereit. Er besteht aus den drei Servicebereichen EPS, HEPS und GPPS. Weitere Informationen finden Sie unter www.SAPOS.GeoNord.de

SAPOS® Geodätischer Postprocessing Positionierungs-Service - GPPS

Der Geodätischer Postprocessing Positionierungs-Service (GPPS) ist einer von drei Servicebereichen des Satellitenpositionierungsdienstes (SAPOS®) der deutschen Landesvermessung. Angemeldete Nutzer können die Korrektur- und Beobachtungsdaten von den hessischen SAPOS®-Referenzstationen erwerben oder eine Onlineberechnung von amtlichen ETRS89-Positionen aus Roverbeobachtungen durchführen lassen. Für die nachträgliche Positionierungsverbesserung der Satellitenmessungen werden Korrekturdaten im Format RINEX 2.11 (Codekorrekturen) angeboten. Verfügbare Referenzsysteme sind: ETRS89 (geographic 3D) (EPSG:4937) und WGS84 (geographic 3D) (EPSG:4979). Bitte beachten Sie, dass zum 30.06.2017 das neue Höhenbezugssystem DHHN16 eingeführt wird.

Petrological, geochemical and isotopic characterization of kamafugites from East-Central Africa, Italy and Brazil: a review

Kamafugites are 'exotic igneous rocks' with mineralogical and chemical compositions that differ from those observed in common magmas. Despite their importance, kamafugites are still a poorly constrained topic and they lack a general petrological model due to their variable petrographic, geochemical and isotopic features. A detailed comparison among kamafugites is necessary to obtain a deeper understanding of the processes involved in their petrogenesis and of their strongly metasomatised mantle sources. Therefore, this data publication doesn’t only provide new geochemical and isotopic data from kamafugites, but a comprehensive data compilation for kamafugite samples in the Western branch of the East Africa Rift (WEAR) in Uganda and Democratic Republic of Congo, the Intra-Apennine Province (IAP), as well as for the Alto Paranaiba (APIP) and Goiás (GAP) provinces in Brazil. 97 kamafugite whole-rock data for the WEAR, 42 for IAP and 51 for APIP and GAP have been collected and compared to highlight similarities and differences, aiming to reconstruct their petrogenesis. The new data in this data publication results from work conducted at Laboratory of Geochronology and Radiogenic Isotope Geochemistry - Pisa1 (IGG-CNR, Italy) supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005.

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.

3D microXCT scans of 1mm pumiceous clasts from Rungwe Pumice eruption deposit (Tanzania)

The dataset comprises 3D micro XCT scans collected with a ZEISS Xradia Versa 410 at the Istituto Nazionale di Geofisica e Vulcanologia-Osservatorio Vesuviano (Italy). Samples are ash particles within the 0/-0.5 φ (1-1.4 mm) grain size range collected from different stratigraphic horizons (C, F, I, L, O) of the type section (KF176) of the 4ka Rungwe Pumice Plinian eruption (Tanzania). A total of 4001 bidimensional X-ray absorption projections were collected during a 360° rotation of the sample at 80 kV and 7 W. For each sample a scan was collected using a 10x magnification lens, additionally, for specific samples, a further scan with a 20x lens was also collected at 150 kV and 10 W. The pixel size results in 2 µm/px (8 µm^3/voxel) for samples scanned with 10x lens and 1.1 µm/px (1.3 µm^3/voxel ) for samples scanned with 20x lens. When necessary, a low-energy (LE1) filter was used to minimise beam hardening. The scans were then reconstructed into tomographic volumes using the integrated XRM Reconstructor software.

Dataset of wehrlitization process: insights from X-ray Micro-CT of Mt. Vulture (southern Italy) mantle xenoliths

The study of textural and chemical characteristics of mafic minerals from mantle xenoliths is essential to investigate the nature of the upper mantle in a continental geodynamic context, melts generation and their effects related to mantle metasomatism. Particular textures in mantle minerals, inclusions or secondary veins of different nature (silicates vs carbonates), bubbles, represent petrographic tools to investigate these processes within the mantle. Petrographic 2D thin sections might overlook these mineralogical features, and 3D textural analysis through X-ray computed microtomography (micro-CT) are crucial to overcome these limitations. We focused on the Mt. Vulture volcano (southern Italy) rare mantle xenoliths, brought to the surface by a melilitite-carbonatite magma (141 ka), with particular emphasis to spinel-wehrlite xenoliths and wehrlitization processes that is located close to an area of intense CO2 degassing associated to catastrophic earthquakes. Preliminary results showed interesting 3D textural distributions within the studied xenoliths-forming mantle minerals. In particular, the micro-CT allowed to furnish new constrains on the relationship between fluids entrapment and migration, and structural discontinuities. Indeed, some minerals (especially those from the wehrlite xenoliths) showed a well-correlated distribution of fluid inclusions along the secondary fracturing planes. This publication results from work conducted under the transnational access/national open access action at Istituto Nazionale di Geofisica e Vulcanologia – Osservatorio Vesuviano (INGV-OV) and supported by WP3 ILGE - MEET project, PNRR - EU Next Generation Europe program, MUR grant number D53C22001400005. The author thanks also Gianmarco Buono and Lucia Pappalardo for their support during the analyses and the post processing process.

Results of analogue tectonic models of rifting and tectonic lineament reactivation along the Main Ethiopian Rift

This data set includes results from a total of 13 analogue tectonic models aimed at simulating the activation of tectonic lineaments associated with the Main Ethiopian Rift in eastern Africa. We use a model set-up based on previous work by Zwaan et al. (2021, 2022). This set-up involves a velocity discontinuity (VD, i.e., the edge of a mobile base plate) to induce extension in the overlying brittle- and viscous model materials representing the upper and lower crust, respectively. Additional structural weaknesses (seeds) at the base of the brittle layer serve to represent activated tectonic weaknesses in nature. Model parameters (different VD and seed orientation, and different seed diameters) are summarized in Table 1. The model results presented in this data publication are obtained through Digital Image Correlation (DIC) and Structure-from-Motion (SfM) analyses. A more detailed description of model set-up, model results, and their interpretation can be found in Zwaan et al. (2025)

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