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Volume 10 Number 2
  • ISSN: 1569-4445
  • E-ISSN: 1873-0604

Abstract

ABSTRACT

High‐resolution seismic profiles acquired in the eastern sector of Lago Fagnano, the southernmost ice‐free lake in the world, have shown the presence of very shallow gas‐bearing layers in the upper sedimentary sequences. The gas‐related features observed on seismic profiles include a typical, very strong reflection with reversed polarity, multiple reflections and acoustic blanking that hide subsurface sedimentary and structural features. The top of the acoustically high‐amplitude layer is located between 0.3–1.7 m below the lake floor. It generally forms a sharp boundary, often marked by a varying offset probably due to different levels of gas penetration, which could be related to the lithology of the overlying sediments. To confirm the presence of gas, some gravity cores were recovered in places where the blanking effect was most relevant and in the supposed gas‐free zone. Sediment core analyses have highlighted the occurrence of significant organic‐rich components within the uppermost, largely unconsolidated sedimentary layers, in correspondence of the seismically‐detected gassy zone, whereas only a few organic layers were found in the gas‐free zone. We assume that the main origin of gas is linked to the presence of a shallow, thin peat‐rich layer of Middle‐Late Holocene age. In fact, the mapped gassy zone occurs in correspondence of the outlet of the Rio Turbio, the principal tributary of Lago Fagnano, which discharges waters coming from a relatively small sag pond located immediately to the east of the eastern shore of the lake. To date, this is the first evidence of shallow gas in Tierra del Fuego lakes.

© European Association of Geoscientists and Engineers © 2012 European Association of Geoscientists and Engineers
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2011-08-01
2024-04-18

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References

  1. AndersonA.L. and HamptonL.D.1980. Acoustics of gas‐bearing sediments I. Background. Journal of the Acoustical Society of America67, 1865–1889.
     [Google Scholar]
  2. ArizteguiD., AnselmettiF.S., GilliA. and WaldmannN.2008. Late Pleistocene environmental change in Eastern Patagonia and Tierra del Fuego – A limnogeological approach. In: The Late Cenozoic of Patagonia and Tierra del Fuego (ed. J.Rabassa ), pp. 241–253. Elsevier.
     [Google Scholar]
  3. BaltzerA., TessierB., Nouzé H, BatesR., MooreC. and MenierD.2005. Seistec seismic profiles: A tool to differentiate gas signatures. Marine Geophysical Researches26, 235–245.
     [Google Scholar]
  4. BertinX. and ChaumillonE.2005. New insights in shallow gas generation from very high resolution seismic and bathymetric surveys in the Marennes‐Oléron Bay, France. Marine Geophysical Researches26, 225–233.
     [Google Scholar]
  5. BestA.I., TuffinM.D.J., DixJ.K. and BullJ.M.2004. Tidal height and frequency dependence of acoustic velocity and attenuation in shallow gassy marine sediments. Journal of Geophysical Research109, B08101. doi:10.1029/2003JB002748
     [Google Scholar]
  6. BujaleskyG., HeusserC., CoronatoA., RoigC. and RabassaJ.1997. Pleistocene glaciolacustrine sedimentation at Lago Fagnano, Andes of Tierra del Fuego, Southernmost South America. Quaternary Science Reviews16, 767–778.
     [Google Scholar]
  7. ClappertonC.M.1990. Quaternary glaciations in the southern hemisphere: An overview. Quaternary Science Reviews9, 299–304.
     [Google Scholar]
  8. CoronatoA., Seppälä M., PonceJ.F. and RabassaJ.2009. Glacial geo‐morphology of the Pleistocene Lake Fagnano ice lobe, Tierra del Fuego, southern South America. Geomorphology112, 67–81.
     [Google Scholar]
  9. EmeryK.O. and HogganD.1958. Gases in marine sediments. AAPG Bulletin42, 2174–2188.
     [Google Scholar]
  10. FinckhP., KeltsK. and LambertA.1984. Seismic stratigraphy and bedrock forms in perialpine lakes. Geological Society of America Bulletin95, 1118–1128.
     [Google Scholar]
  11. Garcia‐GilG., VilasF. and Garcia‐GarciaA.2002. Shallow gas features in incised‐valley fills (Ria de Vigo, NW Spain): A case study. Continental Shelf Research22, 2303–2315.
     [Google Scholar]
  12. Gwang H.Lee, Dae C.Kim, Han J.Ki, Hyeong T.Jou, Young J.Lee (2005): Shallow gas in the central part of the Korea Strait shelf mud off the southeastern coast of Korea. Continental Shelf Research, 25, 2036–2052.
     [Google Scholar]
  13. JuddA.G. and HovlandM.2007. Seabed Fluid Flow: The Impact of Geology, Biology and the Marine Environment.Cambridge University Press.
     [Google Scholar]
  14. KoyamaT.1953. Measurement and analysis of gases in lake muds. Journal of Earth Sciences (Nagoya University)1, 107–118.
     [Google Scholar]
  15. LeeG.H., KimD.C., KimH.J., JouH.T. and LeeY.J.2005. Shallow gas in the central part of the Korea Strait shelf mud off the southeastern coast of Korea. Continental Shelf Research25, 2036–2052.
     [Google Scholar]
  16. LodoloE., LippaiH., TassoneA., ZanollaC., MenichettiM. and HormaecheaJ.‐L.2007. Gravity map of the Isla Grande de Tierra del Fuego, and morphology of Lago Fagnano. Geologica Acta4, 307–314.
     [Google Scholar]
  17. LodoloE., MenichettiM., BartoleR., Ben‐AvrahamZ., TassoneA. and LippaiH.2003. Magallanes‐Fagnano continental transform fault (Tierra del Fuego, southernmost South America). Tectonics22, 1076. doi:10.1029/2003TC001500
     [Google Scholar]
  18. LodoloE., MenichettiM., TassoneA., GelettiR., SterzaiP., LippaiH. and HormaecheaJ.‐L.2002. Researchers target a continental transform fault in Tierra del Fuego. EOS Transactions83, 1–5.
     [Google Scholar]
  19. LomnitzC.1970. Major earthquakes and tsunamis in Chile during the period 1535 to 1955. Geologische Rundschau59, 938–960.
     [Google Scholar]
  20. MacDonaldG.M., BeilmanD.W., KremenetskiK.V., ShengY., SmithL.C. and VelichkoA.A.2006. Rapid early development of circumarctic peatlands and atmospheric CH4 and CO2 variations. Science314, 285–288.
     [Google Scholar]
  21. MathysM., ThießenO., TheilenF. and SchmidtM.2005. Seismic characterisation of gas‐rich near surface sediments in the Arkona Basin, Baltic Sea. Marine Geophysical Research26, 207–224.
     [Google Scholar]
  22. MenichettiM., LodoloE. and TassoneA.2008. Structural geology of the Fuegian Andes and Magallanes fold‐and‐thrust belt – Tierra del Fuego Island. Geologica Acta6, 19–42.
     [Google Scholar]
  23. MenichettiM., LodoloE., TassoneA., HormaecheaJ.‐L. and LippaiH.2007. Geologia dell’area del Lago Fagnano in Terra del Fuoco (Sud America). Rendiconti della Societa’ Geologica Italiana4, 251–254.
     [Google Scholar]
  24. MercerJ.H.1976. Glacial history of southernmost South America. Quaternary Research6, 125–166.
     [Google Scholar]
  25. MissiaenT., MurphyS., LonckeL. and HenrietJ.‐P.2002. Very highresolution seismic mapping of shallow gas in the Belgian coastal zone. Continental Shelf Research22, 2291–2301.
     [Google Scholar]
  26. TassoneA., LippaiH., LodoloE., MenichettiM., CombaA., HormaecheaJ.‐L. and VilasJ.F.2005. A geological and geophysical crustal section across the Magallanes‐Fagnano fault in Tierra del Fuego. Journal of South American Earth Sciences19, 99–109.
     [Google Scholar]
  27. TuffinM.D.J., BestA.I., DixJ.K. and BullJ.M.2000. Temporal variability of P‐wave attenuation due to gas bubbles in a marine sediment. Acoustical Oceanography.Proceedings of the Institute of Acoustics Conference, 9–12 April 2001, Southampton Oceanography Centre, Expanded Abstracts, 291–298.
     [Google Scholar]
  28. WaldmannN., ArizteguiD., AnselmettiF.S., AustinJ.A.Jr., DunbarR.B., MoyC.M. and RecasensC.2008. Seismic stratigraphy of Lago Fagnano sediments (Tierra del Fuego, Argentina): A potential archive of paleoclimatic change and tectonic activity since the Late Glacial. Geologica Acta6, 101–110.
     [Google Scholar]
  29. WaldmannN., ArizteguiD., AnselmettiF.S., AustinJ.A.Jr., MoyC.M., SternC.et al.2009. Holocene climatic fluctuations and positioning of the Southern Hemisphere westerlies in Tierra del Fuego (54°S), Patagonia. Journal of Quaternary Science25, 1063–1075. doi:10.1002/jqs.1263
     [Google Scholar]
  30. WaldmannN., ArizteguiD., AnselmettiF.S., CoronatoA. and AustinJ.A.Jr.2010. Geophysical evidence of multiple glacier advances in Lago Fagnano (54°S), southernmost Patagonia. Quaternary Science Reviews29, 1188–1200.
     [Google Scholar]
  31. WilkensR.H. and RichardsonM.D.1998. The influence of gas bubbles on sediment acoustic properties: In situ, laboratory, and theoretical results from Eckernförde Bay, Baltic Sea. Continental Shelf Research18, 1859–1892.
     [Google Scholar]
  32. YuZ., BeilmanD.W., FrolkingS., MacDonaldG.M., RouletN.T., CamillP. and CharmanD.J.2011. Peatlands and their role in the global carbon cycle. EOS Transactions92(12), 97–108.
     [Google Scholar]
  33. ZanollaC., LodoloE., LippaiH., TassoneA., MenichettiM., BaradelloL. et al. 2011. Bathymetric map of Lago Fagnano (Tierra del Fuego Island). Bollettino di Geofisica Teorica e Applicata52, 1–8.
     [Google Scholar]
  34. ZecchinM., BaradelloL., BrancoliniG., DondaF., PizzettoF. and TosiL.2008. Sequence stratigraphy based on high‐resolution seismic profiles in the late Pleistocene and Holocene deposits of the Venice area. Marine Geology253, 185–198.
     [Google Scholar]
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Occurrence of shallow gas in the easternmost Lago Fagnano (Tierra del Fuego)
Near Surface Geophysics 10, 161 (2012); https://doi.org/10.3997/1873-0604.2011040
/content/journals/10.3997/1873-0604.2011040
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