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  • 1
    In: Applied Sciences, MDPI AG, Vol. 10, No. 19 ( 2020-09-27), p. 6759-
    Kurzfassung: In the present work, we demonstrate how drone surveys coupled with structure-from-motion (SfM) photogrammetry can help to collect huge amounts of very detailed data even in rough terrains where logistics can affect classical field surveys. The area of study is located in the NW part of the Krafla Fissure Swarm (NE Iceland), a volcanotectonic rift composed of eruptive centres, extension fractures, and normal faults. The surveyed sector is characterized by the presence of a hyaloclastite ridge composed of deposits dated, on a stratigraphic basis, to the Weichselian High Glacial (29.1–12.1 ka BP), and a series of lava flows mostly dating back to 11–12 ka BP. The integration of remotely sensed surveys and field inspections enabled us to recognize that this segment of the Krafla rift is made of grabens arranged en-échelon with a left-stepping geometry. A major graben increases in width in correspondence of the hyaloclastite cone; we interpret this geometry as resulting from the mechanical contrast between the stiffer lava succession and the softer hyaloclastites, which favours the development of concentric faults. We also measured a total extension of 16.6 m and 11.2 m along the fractures affecting the lava units, and a total extension in the hyaloclastites of 29.3 m. This produces an extension rate of 1.4 mm/yr in the Holocene lavas and 1.7 ± 0.7 mm/yr in the Weichselian hyaloclastite deposits. The spreading direction we obtained for this area is N97.7° E, resulting from the av. of 568 opening direction values.
    Materialart: Online-Ressource
    ISSN: 2076-3417
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2020
    ZDB Id: 2704225-X
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    In: Land, MDPI AG, Vol. 11, No. 3 ( 2022-03-03), p. 377-
    Kurzfassung: In this body of work, we showcase a historic virtual geotrail on the eastern flank of the iconic Mt. Etna volcano (Italy), along a series of outstanding geological sites and features subsequent to an important eruption that took place in 1928. A geohistoric account of such a major eruption, is of great interest, since it is the only event since 1669 to have caused the destruction of a town (Mascali) in the Etna region. Volcanologists, educators, the lay public, tourists and volcano explorers can now access a series of “virtual geostops” belonging to this virtual geotrail, such that “visitors” can virtually fly above these sites by scanning a QR code on the printed or electronic version of the present manuscript, as well as on the poster provided as additional material for this manuscript. The virtual geostops that comprise the virtual geotrail were developed using the structure-from-motion (SfM) photogrammetry technique from images captured by using unmanned aerial vehicles (UAVs). The main result of our work is the virtual geotrail, subdivided in two parts and composed of eight geostops, each showing outstanding examples of geological features resulting from volcanic phenomena that took place also during 1979. Our approach is designed to support classical field trips, and it can undoubtedly become complementary to traditional field teaching in earth sciences, both now and in the future.
    Materialart: Online-Ressource
    ISSN: 2073-445X
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2022
    ZDB Id: 2682955-1
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    In: Italian Journal of Geosciences, Societa Geologica Italiana, Vol. 142, No. 3 ( 2023-10), p. 1-6
    Materialart: Online-Ressource
    ISSN: 2038-1719
    Sprache: Englisch
    Verlag: Societa Geologica Italiana
    Publikationsdatum: 2023
    ZDB Id: 2663983-X
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  • 4
    In: Applied Sciences, MDPI AG, Vol. 11, No. 12 ( 2021-06-12), p. 5466-
    Kurzfassung: We document and show a state-of-the-art methodology that could allow geoheritage sites (geosites) to become accessible to scientific and non-scientific audiences through immersive and non-immersive virtual reality applications. This is achieved through a dedicated WebGIS platform, particularly handy in communicating geoscience during the COVID-19 era. For this application, we selected nine volcanic outcrops in Santorini, Greece. The latter are mainly associated with several geological processes (e.g., dyking, explosive, and effusive eruptions). In particular, they have been associated with the famous Late Bronze Age (LBA) eruption, which made them ideal for geoheritage popularization objectives since they combine scientific and educational purposes with geotourism applications. Initially, we transformed these stunning volcanological outcrops into geospatial models—the so called virtual outcrops (VOs) here defined as virtual geosites (VGs)—through UAV-based photogrammetry and 3D modeling. In the next step, we uploaded them on an online platform that is fully accessible for Earth science teaching and communication. The nine VGs are currently accessible on a PC, a smartphone, or a tablet. Each one includes a detailed description and plenty of annotations available for the viewers during 3D exploration. We hope this work will be regarded as a forward model application for Earth sciences’ popularization and make geoheritage open to the scientific community and the lay public.
    Materialart: Online-Ressource
    ISSN: 2076-3417
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2021
    ZDB Id: 2704225-X
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  • 5
    In: Remote Sensing, MDPI AG, Vol. 12, No. 13 ( 2020-06-30), p. 2093-
    Kurzfassung: Coral reefs are declining worldwide as a result of the effects of multiple natural and anthropogenic stressors, including regional-scale temperature-induced coral bleaching. Such events have caused significant coral mortality, leading to an evident structural collapse of reefs and shifts in associated benthic communities. In this scenario, reasonable mapping techniques and best practices are critical to improving data collection to describe spatial and temporal patterns of coral reefs after a significant bleaching impact. Our study employed the potential of a consumer-grade drone, coupled with structure from motion and object-based image analysis to investigate for the first time a tool to monitor changes in substrate composition and the associated deterioration in reef environments in a Maldivian shallow-water coral reef. Three key substrate types (hard coral, coral rubble and sand) were detected with high accuracy on high-resolution orthomosaics collected from four sub-areas. Multi-temporal acquisition of UAV data allowed us to compare the classified maps over time (February 2017, November 2018) and obtain evidence of the relevant deterioration in structural complexity of flat reef environments that occurred after the 2016 mass bleaching event. We believe that our proposed methodology offers a cost-effective procedure that is well suited to generate maps for the long-term monitoring of changes in substrate type and reef complexity in shallow water.
    Materialart: Online-Ressource
    ISSN: 2072-4292
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2020
    ZDB Id: 2513863-7
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  • 6
    In: Solid Earth, Copernicus GmbH, Vol. 12, No. 4 ( 2021-04-13), p. 801-816
    Kurzfassung: Abstract. We collected drone data to quantify the kinematics at extensional fractures and normal faults, integrated this information with seismological data to reconstruct the stress field, and critically compared the results with previous fieldwork to assess the best practice. As a key site, we analyzed a sector of the northeast rift of Mt Etna, an area affected by continuous ground deformation linked to gravity sliding of the volcano's eastern flank and dike injections. The studied sector is characterized also by the existence of eruptive craters and fissures and lava flows. This work shows that this rift segment is affected by a series of NNE- to NE-striking, parallel extensional fractures characterized by an opening mode along an average N105.7∘ vector. The stress field is characterized by a σHmin trending northwest–southeast. Normal faults strike parallel to the extensional fractures. The extensional strain obtained by cumulating the net offset at extensional fractures with the fault heave gives a stretching ratio of 1.003 in the northeastern part of the study area and 1.005 in the southwestern part. Given a maximum age of 1614 CE for the offset lavas, we obtained an extension rate of 1.9 cm yr−1 for the last 406 years. This value is consistent with the slip along the Pernicana Fault system, confirming that the NE rift structures accommodate the sliding of the eastern flank of the volcano.
    Materialart: Online-Ressource
    ISSN: 1869-9529
    Sprache: Englisch
    Verlag: Copernicus GmbH
    Publikationsdatum: 2021
    ZDB Id: 2545676-3
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    Online-Ressource
    Online-Ressource
    Springer Science and Business Media LLC ; 2017
    In:  Environmental Monitoring and Assessment Vol. 189, No. 8 ( 2017-8)
    In: Environmental Monitoring and Assessment, Springer Science and Business Media LLC, Vol. 189, No. 8 ( 2017-8)
    Materialart: Online-Ressource
    ISSN: 0167-6369 , 1573-2959
    Sprache: Englisch
    Verlag: Springer Science and Business Media LLC
    Publikationsdatum: 2017
    ZDB Id: 2012242-1
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  • 8
    Online-Ressource
    Online-Ressource
    Frontiers Media SA ; 2022
    In:  Frontiers in Earth Science Vol. 10 ( 2022-10-25)
    In: Frontiers in Earth Science, Frontiers Media SA, Vol. 10 ( 2022-10-25)
    Kurzfassung: The origin of modern seafloor methane emissions in the Barents Sea is tightly connected to the glacio-tectonic and oceanographic transformations following the last ice age. Those regional events induced geological structure re-activation and destabilization of gas hydrate reservoirs over large areas of the European continental margins, sustaining widespread fluid plumbing systems. Despite the increasing number of new active seep discoveries, their accurate geochronology and paleo-dynamic is still poorly resolved, thus hindering precise identification of triggering factors and mechanisms controlling past and future seafloor emissions. Here, we report the distribution, petrographic (thin section, electron backscatter diffraction), isotopic (δ 13 C, δ 18 O) and lipid biomarker composition of methane-derived carbonates collected from Leirdjupet Fault Complex, SW Barents Sea, at 300 m depth during an ROV survey in 2021. Carbonates are located inside a 120 x 220 m elongated pockmark and form & lt;10 m 2 bodies protruding for about 2 m above the adjacent seafloor. Microstructural analyses of vein-filling cements showed the occurrence of three–five generations of isopachous aragonitic cement separated by dissolution surfaces indicative of intermittent oxidizing conditions. The integration of phase-specific isotopic analysis and U/Th dating showed δ 13 C values between −28.6‰ to −10.1‰ and δ 18 O between 4.6‰ and 5.3‰, enabling us to track carbonate mineral precipitation over the last ∼8 ka. Lipid biomarkers and their compound-specific δ 13 C analysis in the bulk carbonate revealed the presence of anaerobic methanotrophic archaea of the ANME-2 clade associated with sulfate-reducing bacteria of the Seep-SRB1 clade, as well as traces of petroleum. Our results indicate that methane and petroleum seepage in this area followed a similar evolution as in other southernmost Barents Sea sites controlled by the asynchronous deglaciation of the Barents Sea shelf, and that methane-derived carbonate precipitation is still an active process at many Arctic locations.
    Materialart: Online-Ressource
    ISSN: 2296-6463
    Sprache: Unbekannt
    Verlag: Frontiers Media SA
    Publikationsdatum: 2022
    ZDB Id: 2741235-0
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  • 9
    Online-Ressource
    Online-Ressource
    Springer Science and Business Media LLC ; 2022
    In:  Coral Reefs Vol. 41, No. 2 ( 2022-04), p. 253-264
    In: Coral Reefs, Springer Science and Business Media LLC, Vol. 41, No. 2 ( 2022-04), p. 253-264
    Kurzfassung: The cushion seastar Culcita schmideliana has gained major attention in the last few years because of its selective predation on juvenile corals, as well as its ability to generate large demographic assemblages, causing delays in coral recovery after large mortality events in the Republic of Maldives. However, a lack of data regarding the factors affecting its distribution and habitat selection still persists in this area. Here, we adopted a novel approach in the study of corallivorous seastar habitat selection that combined ecological and digital photogrammetry data. In this regard, we tested 3 different parameters as factors influencing seastar habitat choice in the South-East region of Faafu Atoll, Republic of Maldives, namely prey abundance, Linear Rugosity Index (LRI), and Average Slope (AS). The analysis of selectivity coefficient (Ei) of seastars for different habitat types showed a preference for reefs characterized by medium AS values (Ei = 0.268), a LRI included between 2 and 2.5 (Ei = 0.180), and a juvenile coral density ranging between 10 and 20 colonies m −2 (Ei = 0.154). A multiple linear regression analysis showed that different AS and LRI values explained the 43.1% ( R 2  = 0.431, P  = 0.007) and the 48.1% ( R 2  = 0.481, P  = 0.024) of variance in seastars abundance, respectively, while juvenile coral densities did not significantly affect this ( R 2  = 0.132, P  = 0.202). These results provide new information on the distribution and behaviour of an important corallivore of Maldivian reefs, such as C. schmideliana .
    Materialart: Online-Ressource
    ISSN: 0722-4028 , 1432-0975
    Sprache: Englisch
    Verlag: Springer Science and Business Media LLC
    Publikationsdatum: 2022
    ZDB Id: 9047-5
    ZDB Id: 1472576-9
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
    Online-Ressource
    Online-Ressource
    Frontiers Media SA ; 2023
    In:  Frontiers in Marine Science Vol. 10 ( 2023-10-31)
    In: Frontiers in Marine Science, Frontiers Media SA, Vol. 10 ( 2023-10-31)
    Kurzfassung: Cold-seeps have a unique geo-ecological significance in the deep-sea environment. They impact the variability of present-day submarine sedimentary environments, affecting the evolution of the landscape over time and creating a variety of submarine landforms, one of which is Mud Volcanoes (MVs). MVs form due to the extrusion of mud, fluids, and gas, mainly methane, from deeper sedimentary layers. These natural gas seepage systems could significantly affect climate change and the global carbon cycle. We present a comprehensive method that combines ROV-based multibeam mapping and underwater photogrammetry to enhance the understanding of the physical relationships between geomorphic units characterizing the Håkon Mosby Mud Volcano (HMMV) and the distribution of associated habitats. HMMV is indeed characterized by high thermal and geochemical gradients from its center to the margins resulting in a clear zonation of chemosynthetic communities. Our approach integrates multi-resolutions and multi-sources data acquired using a work-class ROV. The ROV-based microbathymetry data helped to identify the different types of fine-scale submarine landforms in the central part of HMMV. This revealed three distinct geomorphic units, with the central hummocky region being the most complex. To further study this area, ROV images were analyzed using a defined Structure from Motion workflow producing millimetric resolution 2D and 3D models. Object-Based Image Analysis (OBIA), applied on orthomosaics, allowed us to obtain a fine classification of main benthic communities covering a total area of 940m 2 , including the active seepage area of the hummocky rim. Four major substrate types were identified in these regions: uncovered mud, bacterial mats high-density, bacterial mats low-density, sediments and tubeworms . Their relationship with terrain morphology and seepage activity were investigated at different spatial scales, contributing to a deeper understanding the ecological functioning of cold seep ecosystems in MVs. The applied workflow is proposed as an innovative processing technique for future studies on cold-seep systems. Geomorphic and ecological processes in extreme environments are inherently linked and marked by spatial patterns typifying associated habitats and sedimentary environments. This is poorly investigated in previous studies, leaving a substantial gap in the geomorphological drivers responsible for habitat distribution and extent in cold seep systems.
    Materialart: Online-Ressource
    ISSN: 2296-7745
    Sprache: Unbekannt
    Verlag: Frontiers Media SA
    Publikationsdatum: 2023
    ZDB Id: 2757748-X
    Standort Signatur Einschränkungen Verfügbarkeit
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