GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Gas hydrate in sediments on the Southern Chile continental slope (2019)
    Kiel : Universitätsbibliothek Kiel
    Details Availability
    Keywords: Hochschulschrift
    Type of Medium: Online Resource
    Pages: 1 Online-Ressource (xii, 95 Seiten) , Illustrationen
    URL: https://nbn-resolving.org/urn:nbn:de:gbv:8-mods-2019-00004-9
    URL: https://d-nb.info/1202630014/34
    URL: https://macau.uni-kiel.de/receive/macau_mods_00000006
    URN: urn:nbn:de:gbv:8-mods-2019-00004-9
    DDC: 553.2
    Language: English
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    GEOMAR CATALOGUE
    Link to Library Catalog
    get availability status
  • 2
    facet.materialart.
    Unknown
    A first estimation of gas hydrates offshore Patagonia (Chile) (2018)
    Elsevier
    In:  Marine and Petroleum Geology, 96 . pp. 232-239.
    Details
    Publication Date: 2021-02-08
    Description: In many places along the central and southern Chilean active continental margin sedimentary successions covering the forearc contain methane hydrate, resulting from a mixture of biogenic and thermogenic processes. Here, we report the spatial distribution of gas hydrate in the accretionary prism and forearc sediments offshore western Patagonia (50°S and 57°S), landward of the Antarctica-South America plate boundary. Knowledge of the forearc structure here is limited, owing to the small number of reflection seismic profiles available, lack of high-resolution bathymetry data and the absence of scientific drillholes. However bottom-simulating reflectors (BSR) indicative of gas hydrate occur regionally extensive below about one third of the forearc slope, between about 280 and 630 m below sea floor. BSR-derived heat flow was calculated at about 30 and 70 mWm−2. These are typical values above subduction zones of oceanic crust older than 10 Ma, where vigorous fluid flow above young and hot subducting oceanic crust has leveled off. To move towards an estimate of gas hydrate present in the sediments, the velocity model was converted into a gas-phase concentration model using data from one of the seismic sections. Average thickness of gas hydrate is about 290 m, and average concentrations estimated are in a range of 3.4%–10%. If we use the minimum value of 3.4%, the amount of methane present in the region is about 3.0 × 1013 m3 at standard pressure-temperature conditions. We conclude that the Pacific forearc of Patagonia area is an important reservoir of methane hydrates and we propose this area be considered as a potential methane hydrate concentrated zone and a key area to be investigated in the future.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.marpetgeo.2018.06.002
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
    facet.materialart.
    Unknown
    High Gas Hydrate and Free Gas Concentrations: An Explanation for Seeps Offshore South Mocha Island (2018)
    MDPI AG
    In:  Energies, 11 (Article 3062).
    Details
    Publication Date: 2021-02-08
    Description: Recent studies have reported shallow and deep seep areas offshore Mocha island. Gas hydrate occurrences along the Chilean margin could explain seeps presence. Gas phases (gas hydrate and free gas) and geothermal gradients were estimated analysing two seismic sections. Close to Mocha island (up to 20 km) were detected high (up to 1900 m/s) and low (1260 m/s) velocities associated with high gas hydrate (up to 20 % of total volume) and free gas (up to 1.1% of total volume) concentrations respectively. These values are in agreement with a variable and high geothermal gradient (65 to 110 °C/km) related to high supply deep fluids canalised by faults and fractures. Faraway from Mocha island (more than 60 km), free gas concentrations decrease to 0.3 % of total volume and low geothermal gradient (from 35 to 60 °C/km) are associated with low fluids supply. Finally, we propose gas hydrate dissociation processes as the main supply source for seeps in the vicinity of Mocha island. These processes can be triggered by ancient sliding reported in literature.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    DOI: 10.3390/en11113062
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
    facet.materialart.
    Unknown
    Gas Hydrate and Free Gas Concentrations in Two Sites inside the Chilean Margin (Itata and Valdivia Offshores) (2017)
    MDPI AG
    In:  Energies, 10 (12). p. 2154.
    Details
    Publication Date: 2020-02-06
    Description: Two sectors, Itata and Valdivia, which are located in the Chilean margin were analysed by using seismic data with the main purpose to characterize the gas hydrate concentration. Strong lateral velocity variations are recognised, showing a maximum value in Valdivia offshore (2380 ms−1 above the BSR) and a minimum value in the Itata offshore (1380 m·s−1 below the BSR). In both of the sectors, the maximum hydrate concentration reaches 17% of total volume, while the maximum free gas concentration is located Valdivia offshore (0.6% of total volume) in correspondence of an uplift sector. In the Itata offshore, the geothermal gradient that is estimated is variable and ranges from 32 °C·km−1 to 87 °C·km−1, while in Valdivia offshore it is uniform and about 35 °C·km−1. When considering both sites, the highest hydrate concentration is located in the accretionary prism (Valdivia offshore) and highest free gas concentration is distributed upwards, which may be considered as a natural pathway for lateral fluid migration. The results that are presented here contribute to the global knowledge of the relationship between hydrate/free gas presence and tectonic features, such as faults and folds, and furnishes a piece of the regional hydrate potentiality Chile offshore.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.3390/en10122154
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 5
    facet.materialart.
    Unknown
    Gas hydrate and free gas estimation from seismic analysis offshore Chiloé island (Chile) (2016)
    Servicio Nacional de Geología y Minería (SERNAGEOMIN)
    In:  Andean Geology, 43 (3). pp. 263-274.
    Details
    Publication Date: 2019-02-01
    Description: In this study one seismic section offshore Chiloé Island was analyzed to better define the seismic character of the hydrate-bearing sediments. The velocity analysis was used to estimate the gas-phase concentration and relate it to the geological features. The velocity model allowed us to recognize two important layers that characterize hydrate- and free gas-bearing sediments above and below the BSR respectively: one located above the BSR, characterized by high velocity (1,800-2,200 m/s) and a second one, below the BSR, characterized by low velocity (1,600-1,700 m/s). A weak reflector at about 100 m below the BSR marks the base of the second layer. AVO analysis and offset stack sections confirming that the reflector interpreted as BGR is related to free gas presence in the pore space. The velocity field is affected by lateral variation, showing maximum (above the BSR) and minimum (below the BSR) values in the sector. Here, the highest gas hydrate and free gas concentrations were calculated, obtaining 9.5% and 0.5% of total volume respectively. A variable BSR depth (from 300 to 600 mbsf) can be justified supposing a variable geothermal gradient (from 25 to 45 °C/km).
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.5027/andgeoV43n3-a02
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 6
    facet.materialart.
    Unknown
    Heat flow in the Southern Chile Forearc controlled by large-scale tectonic processes (2012)
    The Future Ocean
    Details
    Publication Date: 2023-11-08
    Type: Conference or Workshop Item , NonPeerReviewed
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Poster
  • 7
    facet.materialart.
    Unknown
    Gas hydrate versus seabed morphology offshore Lebu (Chilean margin) (2020)
    Nature Research
    Details
    Publication Date: 2023-02-08
    Description: Gas-hydrate occurrences along the Chilean margin have been widely documented, but the processes associated with fluid escapes caused by the dissociation of gas hydrates are still unknown. We report a seabed morphology growth related to fluid migration offshore Lebu associated with mud cones by analysing oxygen and deuterium stable water isotopes in pore water, bathymetric, biological and sedimentological data. A relief was observed at − 127 m water depth with five peaks. Enrichment values of δ 18 O (0.0–1.8‰) and δD (0.0–5.6‰) evidenced past hydrate melting. The orientation of the relief could be associated with faults and fractures, which constitute pathways for fluid migration. The benthic foraminifera observed can be associated with cold seep areas. We model that the mud cones correspond to mud growing processes related to past gas-hydrate dissociation. The integration of (i) the seismic data analysis performed in the surrounding area, (ii) the orientation of our studied relief, (iii) the infaunal foraminifera observed, (iv) the grain size and (v) the total organic matter and isotope values revealed that this area was formerly characterised by the presence of gas hydrates. Hence, this part of the Chilean margin represents a suitable area for investigating fluid-migration processes.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 8
    facet.materialart.
    Unknown
    Gas hydrate in sediments on the Southern Chile continental slope (2019)
    In:  (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, Germany, XII, 95 pp
    Details
    Publication Date: 2022-01-31
    Description: The convergent plate margin of Chile has vast mineral resources associated with active or fossil hydrothermal systems. One of the natural resources that came into the focus of the Chilean government and institutions is gas hydrate in the offshore area of the Pacific Ocean margin, which is a solid ice-like form of water that contains gas molecules highly‐concentrated in methane. To identify the presence of hydrates, in this thesis it was used the bottom-simulating reflector BSR, which has the half amplitude and opposite polarity relative to the seafloor. Moreover, fluids play a key role in the nucleation and rupture propagation of earthquakes in convergent margins, since are a major agent of advective heat transfer from depth to the Earth’s surface. If we provide enough information for the regional heat flow, we will improve our knowledge of the tectono-thermal signature of the convergent margins. For this purpose, it is crucial to know the BSR-depth, which serves to calculate the steady-state heat flow q (mW m–2) by using a simple formula, and therefore, the heat flow can be envisaged in a regional overview. This thesis aims to investigate the tectonic processes of the Chilean forearc through the calculation of the regional BSR-derived heat flow, identification of fluid escape sites, description of the distribution of gas hydrates and estimation of the gas hydrate and free gas reservoirs.
    Type: Thesis , NonPeerReviewed
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Thesis - not published by a publisher
  • 9
    facet.materialart.
    Unknown
    Gas Hydrate Estimate in an Area of Deformation and High Heat Flow at the Chile Triple Junction (2019)
    MDPI
    In:  Geosciences, 9 (28).
    Details
    Publication Date: 2022-01-31
    Description: Large amounts of gas hydrate are present in marine sediments offshore Taitao Peninsula, near the Chile Triple Junction. Here, marine sediments on the forearc contain carbon that is converted to methane in a regime of very high heat flow and intense rock deformation above the downgoing oceanic spreading ridge separating the Nazca and Antarctic plates. This regime enables vigorous fluid migration. Here, we present an analysis of the spatial distribution, concentration, estimate of gas-phases (gas hydrate and free gas) and geothermal gradients in the accretionary prism, and forearc sediments offshore Taitao (45.5°–47° S). Velocity analysis of Seismic Profile RC2901-751 indicates gas hydrate concentration values 〈10% of the total rock volume and extremely high geothermal gradients (〈190 °C·km−1). Gas hydrates are located in shallow sediments (90–280 m below the seafloor). The large amount of hydrate and free gas estimated (7.21 × 1011 m3 and 4.1 × 1010 m3; respectively), the high seismicity, the mechanically unstable nature of the sediments, and the anomalous conditions of the geothermal gradient set the stage for potentially massive releases of methane to the ocean, mainly through hydrate dissociation and/or migration directly to the seabed through faults. We conclude that the Chile Triple Junction is an important methane seepage area and should be the focus of novel geological, oceanographic, and ecological research.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.3390/geosciences9010028
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 10
    facet.materialart.
    Unknown
    Energies, Vol. 10, Pages 2154: Gas Hydrate and Free Gas Concentrations in Two Sites inside the Chilean Margin (Itata and Valdivia Offshores) (2017)
    MDPI Publishing
    In: Energies
    Details
    Publication Date: 2017-12-17
    Description: Energies, Vol. 10, Pages 2154: Gas Hydrate and Free Gas Concentrations in Two Sites inside the Chilean Margin (Itata and Valdivia Offshores) Energies doi: 10.3390/en10122154 Authors: Vargas-Cordero Iván Tinivella Umberta Villar-Muñoz Lucía Two sectors, Itata and Valdivia, which are located in the Chilean margin were analysed by using seismic data with the main purpose to characterize the gas hydrate concentration. Strong lateral velocity variations are recognised, showing a maximum value in Valdivia offshore (2380 ms−1 above the BSR) and a minimum value in the Itata offshore (1380 m·s−1 below the BSR). In both of the sectors, the maximum hydrate concentration reaches 17% of total volume, while the maximum free gas concentration is located Valdivia offshore (0.6% of total volume) in correspondence of an uplift sector. In the Itata offshore, the geothermal gradient that is estimated is variable and ranges from 32 °C·km−1 to 87 °C·km−1, while in Valdivia offshore it is uniform and about 35 °C·km−1. When considering both sites, the highest hydrate concentration is located in the accretionary prism (Valdivia offshore) and highest free gas concentration is distributed upwards, which may be considered as a natural pathway for lateral fluid migration. The results that are presented here contribute to the global knowledge of the relationship between hydrate/free gas presence and tectonic features, such as faults and folds, and furnishes a piece of the regional hydrate potentiality Chile offshore.
    Electronic ISSN: 1996-1073
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by MDPI Publishing
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...