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
Filter
  • Drift tube  (1)
  • MeBo drilling  (1)
  • electrical resistivity  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Non-destructive porosity determinations of antarctic marine sediments derived from resistivity measurements with an inductive method (1993)
    Springer
    Marine geophysical researches 15 (1993), S. 201-218 
    Details
    ISSN: 1573-0581
    Keywords: porosity ; electrical resistivity ; non-destructive inductive method ; sea floor sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The fractional porosity of marine sediments is one of the fundamental index properties of rocks. For the determination of porosity a nondestructive, inductive method was used on unsplit sediment cores. The results were compared with galvanically measured resistivities using a miniature Wenner array on split cores. The measurements agree well except for cores with high clay content where measurement frequency related effects cause a resistivity difference of about 10%. Porosities were derived from resistivities using a published resistivity-porosity relationship by Boyce (1968) and compared with sample porosities. A comparison of both data sets shows good agreement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01204233
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Drift tube investigations on the reactions of O 2 + with CH4 and of CO 2 + with NO in various buffer gases (1981)
    Springer
    Plasma chemistry and plasma processing 1 (1981), S. 65-71 
    Details
    ISSN: 1572-8986
    Keywords: Drift tube ; rate coefficients ; internal excitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The influence of internal excitation on the reactions of O 2 + + CH4 and of CO 2 + + NO has been investigated using a slow flow drift tube. The rate coefficients for these reactions obtained as a function of relative kinetic energy in various buffer gases like He, Ne, Ar, and Kr showed higher values under conditions where the internal excitation of the reactant ions was enhanced. For both reactions the lowest reactivity at all kinetic energies was observed to occur in He, indicating that He is the least effective buffer for collisionally inducing internal excitation of molecular ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00566376
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    facet.materialart.
    Unknown
    Thermal Characterization of Pockmarks Across Vestnesa and Svyatogor Ridges, Offshore Svalbard (2021)
    Details
    Publication Date: 2021-07-01
    Description: The Svalbard margin represents one of the northernmost gas hydrate provinces worldwide. Vestnesa Ridge (VR) and Svyatogor Ridge (SR) west of Svalbard are two prominent sediment drifts showing abundant pockmarks and sites of seismic chimney structures. Some of these sites at VR are associated with active gas venting and were the focus of drilling and coring with the seafloor‐deployed MARUM‐MeBo70 rig. Understanding the nature of fluid migration and gas hydrate distribution requires (among other parameters) knowledge of the thermal regime and in situ gas and pore fluid composition. In situ temperature data were obtained downhole at a reference site at VR defining a geothermal gradient of ~78 mK m−1 (heat flow ~95 mW m−2). Additional heat probe data were obtained to describe the thermal regime of the pockmarks. The highest heat flow values were systematically seen within pockmark depressions and were uncorrelated to gas venting occurrences. Heat flow within pockmarks is typically ~20 mW m−2 higher than outside pockmarks. Using the downhole temperature data and gas compositions from drilling we model the regional base of the gas hydrate stability zone (BGHSZ). Thermal modeling including topographic effects suggest a BGHSZ up to 40 m deeper than estimated from seismic data. Uncertainties in sediment properties (velocity and thermal conductivity) are only partially explaining the mismatch. Capillary effects due to small sediment grain sizes may shift the free gas occurrence above the equilibrium BGHSZ. Changes in gas composition or pore fluid salinity at greater depth may also explain the discrepancy in observed and modeled BGHSZ.
    Description: Key Points: Heat flow variations across the Vestnesa and Svyatogor Ridges off Svalbard are correlated with seismic data showing gas hydrate BSRs. In situ temperatures were measured with the MARUM MeBo70 rig up to ~60 mbsf indicating a background thermal gradient of ~78°C/km. Heat flow is significantly higher within the pockmarks but is not correlated to the occurrence of gas venting.
    Description: Statoil http://dx.doi.org/10.13039/501100004342
    Description: CAGE
    Description: German Research Foundation (DFG)
    Keywords: 622.15 ; Svalbard margin ; heat flow ; gas hydrate ; pockmark ; MeBo drilling
    Type: article
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    CITATION GEO-LEO
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...