Ocean and Polar Research

Korea Institute of Ocean Science & Technology (한국해양과학기술원)
권호 표지
DOI QR코드

DOI QR Code

Sedimentary Facies and Evolution of the Cretaceous Deep-Sea Channel System in Magallanes Basin, Southern Chile

마젤란 분지의 백악기 심해저 하도 퇴적계의 퇴적상 및 진화

  • 최문영 (한국해양연구원 부설 극지연구소) ;
  • 손영관 (경상대학교 지구환경학부) ;
  • 조형래 (한국해양연구원 해저환경.자원연구본부) ;
  • 김예동 (한국해양연구원 부설 극지연구소)
  • Published : 2004.09.30
Download PDF
⟨ Previous Next ⟩

Abstract

The Lago Sofia Conglomerate encased in the 2km thick hemipelagic mudstones and thinbedded turbidites of the Cretaceous Cerro Toro Formation, southern Chile, is a deposit of a gigantic submarine channel developed along a foredeep trough. It is hundreds of meters thick kilometers wide, and extends for more than 120km from north to south, representing one of the largest ancient submarine channels in the world. The channel deposits consist of four major facies, including stratified conglomerates (Facies A), massive or graded conglomerates (Facies B), normally graded conglomerates with intraformational megaclasts (Facies C), and thick-bedded massive sandstones (Facies D). Conglomerates of Facies A and B show laterally inclined stratification, foreset stratification, and hollow-fill structures, reminiscent of terrestrial fluvial deposits and are suggestive of highly competent gravelly turbidity currents. Facies C conglomerates are interpreted as deposits of composite or multiphase debris flows associated with preceding hyperconcentrated flows. Facies D sandstones indicate rapidly dissipating, sand-rich turbidity currents. The Lago Sofia Conglomerate occurs as isolated channel-fill bodies in the northern part of the study area, generally less than 100m thick, composed mainly of Facies C conglomerates and intercalated between much thicker fine-grained deposits. Paleocurrent data indicate sediment transport to the east and southeast. They are interpreted to represent tributaries of a larger submarine channel system, which joined to form a trunk channel to the south. The conglomerate in the southern part is more than 300 m thick, composed of subequal proportions of Facies A, B, and C conglomerates, and overlain by hundreds of m-thick turbidite sandstones (Facies D) with scarce intervening fine-grained deposits. It is interpreted as vertically stacked and interconnected channel bodies formed by a trunk channel confined along the axis of the foredeep trough. The channel bodies in the southern part are classified into 5 architectural elements on the basis of large-scale bed geometry and sedimentary facies: (1) stacked sheets, indicative of bedload deposition by turbidity currents and typical of broad gravel bars in terrestrial gravelly braided rivers, (2) laterally-inclined strata, suggestive of lateral accretion with respect to paleocurrent direction and related to spiral flows in curved channel segments around bars, (3) foreset strata, interpreted as the deposits of targe gravel dunes that have migrated downstream under quasi-steady turbidity currents, (4) hollow fills, which are filling thalwegs, minor channels, and local scours, and (5) mass-flow deposits of Facies C. The stacked sheets, laterally inclined strata, and hollow fills are laterally transitional to one another, reflecting juxtaposed geomorphic units of deep-sea channel systems. It is noticeable that the channel bodies in the southern part are of feet stacked toward the east, indicating eastward migration of the channel thalwegs. The laterally inclined strata also dip dominantly to the east. These features suggest that the trunk channel of the Lago Sofia submarine channel system gradually migrated eastward. The eastward channel migration is Interpreted to be due to tectonic forcing imposed by the subduction of an oceanic plate beneath the Andean Cordillera just to the west of the Lago Sofia submarine channel.

Keywords

References

  1. Allen, J.R.L. 1983. Studies in fluviatile sedimentation: bars,bar-complexes and sandstone sheets (low-sinuosity braided streams) in the Brownstone (L. Devonian), Welsh Borders.Sediment. Geol., 33, 237-293. https://doi.org/10.1016/0037-0738(83)90076-3
  2. Belderson, R.H., N.H. Kenyon, A.H. Stride, and C.D. Pelton. 1984. A ‘braided’ distributary system on the Orinoco Deep-Sea Fan. Mar. Geol., 56, 195-206. https://doi.org/10.1016/0025-3227(84)90013-6
  3. Biddle, K.T., M.A. Uliana, R.M.J. Mitchum, M.G. Fitzgerald, and R.C. Wright. 1986. The stratigraphic and structural evolution of the central and eastern Magallanes Basin, southern South America. p. 41-61. In: Foreland Basins. ed. by P. Homewood. Int. Assoc. Sedimentol. Spec. Publ., 8. Blackwell Science, Oxford.
  4. Boothroyd, J.C. and G.M. Ashley. 1975. Processes, bar morphology, and sedimentary structures on braided outwash fans, northeastern Gulf of Alaska. p. 193-222. In: Glaciofluvial and Glaciolacustrine Sedimentation. eds. by A.V. Jopling and B.C. McDonald. Society of Economic Paleontologists and Mineralogists, Special Publication 23, Tulsa.
  5. Bridge, J.S. 1993. The interaction between channel geometry, water flow, sediment transport and deposition in braided rivers. p. 13-71. In: Braided Rivers. eds. by J.L. Best and C.S. Bristow. Geological Society Special Publication 75. London. https://doi.org/10.1144/GSL.SP.1993.075.01.02
  6. Clark, J.D., N.H. Kenyon, and K.T. Pickering. 1992. Quantitative analysis of the geometry of submarine channels: implications for the classification of submarine fans. Geology, 20, 633-636. https://doi.org/10.1130/0091-7613(1992)020<0633:QAOTGO>2.3.CO;2
  7. Clark, J.D. and K.T. Pickering. 1996a. Architectural elements and growth patterns of submarine channels: application to hydrocarbon exploration. Am. Assoc. Petrol. Geol. Bull., 80, 194-221.
  8. Clark, J.D. and K.T. Pickering. 1996b. Submarine Channels: Processes and Architecture. Vallis Press, London. 231 p.
  9. Collinson, J.D. and D.B. Thompson. 1982. Sedimentary Structures. George Allen and Unwin, London. 194 p.
  10. Dalziel, I.W.D. and R.L. Brown. 1989. Tectonic denudation of the Darwin metamorphic core complexes in the Andes of Tierra del Fuego, southernmost Chile: Implications for Cordilleran orogenesis. Geology, 17, 699-703. https://doi.org/10.1130/0091-7613(1989)017<0699:TDOTDM>2.3.CO;2
  11. Damuth, J.E., R.D. Flood, C. Pirmez, and P.L. Manley. 1995. Architectural elements and depositional processes of Amazon Deep Sea Fan imaged by long-range side-scan sonar (GLORIA), bathymetric swath-mapping (Sea Beam), high-resolution seismic and piston-core data. p. 105-122. In: Atlas of Deep Water Environments: Architectural Styles in Turbidite Systems. eds. by K.T. Pickering, R.N. Hiscott, N.H. Kenyon, F. Ricci Lucchi, and R.D.A. Smith. Chapman and Hall, London.
  12. Ercilla, G., B. Alonso, J. Baraza, D. Casas, F.L. Chiocci, F. Estrada, M. Farrán, E. Gonthier, F. Perez-Belzuz, C. Pirmez, M. Reeder, J. Torres, and R. Urgeles. 1998. New high- resolution acoustic data from the ‘braided system’ of the Orinoco deep-sea fan. Mar. Geol., 146, 243-250.
  13. Flood, R.D. and J.E. Damuth. 1987. Quantitative characteristics of sinuous distributary channels on the Amazon Deep-Sea Fan. Geol. Soc. Am. Bull., 98, 728-738. https://doi.org/10.1130/0016-7606(1987)98<728:QCOSDC>2.0.CO;2
  14. Hagen, R.A., D.D. Bergersen, R. Moberly, and W.T. Colbourn. 1994. Morphology of a large meandering submarine canyon system on the Peru-Chile forearc. Mar. Geol., 119, 7-38. https://doi.org/10.1016/0025-3227(94)90138-4
  15. Hein, F.J. and R.G. Walker. 1977. Bar evolution and development of stratification in the gravelly, braided, Kicking Horse River, British Columbia. Can. J. Earth Sci., 14, 562-570. https://doi.org/10.1139/e77-058
  16. Hein, F.J. and R.G. Walker. 1982. The Cambro-Ordovician Cap Enrage Formation, Quebec, Canada: Conglomeratic deposits of a submarine channel with terraces. Sedimentology, 29, 309-329. https://doi.org/10.1111/j.1365-3091.1982.tb01798.x
  17. Hesse, R. 1989. “Drainage system” associated with midocean channels and submarine yazoos: Alternative to submarine fan depositional systems. Geology, 17, 1148-1151. https://doi.org/10.1130/0091-7613(1989)017<1148:DSAWMO>2.3.CO;2
  18. Hughes Clarke, J.E., A.N. Shor, D.J.W. Piper, and L.A. Mayer. 1990. Large-scale current-induced erosion and deposition in the path of the 1929 Grand Banks turbidity current. Sedimentology, 37, 613-629. https://doi.org/10.1111/j.1365-3091.1990.tb00625.x
  19. Jo, H.R., M.Y. Choe, and Y.K. Sohn. 2001. Drainage pattern and fluvial architecture of a gigantic gravelly submarine channel: the Cretaceous Lago Sofia conglomerate,southern Chile. p. 144. In: 7th Int. Conf. Fluvial Sedimentology,Program with Abstracts. eds. by J.A. Mason,J.R.F. Diffendal, and R.M. Joeckel. Conservation and Survey Division, University of Nebraska, Open-File Report 60.
  20. Jo, H.R., C.W. Rhee, and S.K. Chough. 1997. Distinctive characteristics of a streamflow-dominated alluvial fan deposit: Sanghori area, Kyongsang Basin (Early Cretaceous), southeastern Korea. Sediment. Geol., 110, 51-79. https://doi.org/10.1016/S0037-0738(96)00083-8
  21. Johnson, A.M. 1984. Debris flow. p. 257-361. In: Slope Instability. eds. by D. Brunsden and D.B. Prior. John Wiley & Sons, Chichester.
  22. Klaucke, I. and R. Hesse. 1996. Fluvial features in the deepsea: new insights from the glacigenic submarine drainage system of the Northwest Atlantic Mid-Ocean Channel in the Labrador Sea. Sediment. Geol., 106, 223-234. https://doi.org/10.1016/S0037-0738(96)00008-5
  23. Klaucke, I., R. Hesse, and W.B.F. Ryan. 1998. Morphology and structure of a distal submarine trunk channel: The Northwest Atlantic Mid-Ocean Channel between lat 53${^{\circ}N}$ and 44${^{\circ}30'N}$. Geol. Soc. Am. Bull., 110, 22-34. https://doi.org/10.1130/0016-7606(1998)110<0022:MASOAD>2.3.CO;2
  24. Lewis, K.B. 1994. The 1500-km-long Hikurangi Channel: trench-axis channel that escapes its trench, crosses a plateau, and feeds a fan drift. Geo-Mar. Lett., 14, 19-28. https://doi.org/10.1007/BF01204467
  25. Lewis, K.B. and P.M. Barnes. 1999. Kaikoura Canyon, New Zealand: active conduit from near-shore sediment zones to trench-axis channel. Mar. Geol., 162, 39-69. https://doi.org/10.1016/S0025-3227(99)00075-4
  26. Lowe, D.R. 1982. Sediment gravity flows: II. Depositional models with special reference to the deposits of highdensity turbidity currents. J. Sediment. Petrol., 52, 279-297.
  27. Maizels, J.K. 1987. Large-scale flood deposits associated with the formation of coarse-grained, braided terrace sequences. p. 135-148. In: Recent Developments in Fluvial Sedimentology. eds. by F.G. Ethridge, R.M. Flores, and M.D. Harvey. Society of Economic Paleontologists and Mineralogists, Special Publication 39, Tulsa.
  28. Major, J.J. 1997. Depositional processes in large-scale debris-flow experiments. J. Geol., 105, 345-366. https://doi.org/10.1086/515930
  29. Miall, A. 1994. Reconstructing fluvial macroform architecture from two-dimensional outcrops: examples from the Castlegate Sandstone, Book Cliff, Utah. J. Sediment. Petrol., 64B, 146-158.
  30. Miall, A.D. 1989. Architectural elements and bounding surfaces in channelized clastic deposits: Notes on comparisons between fluvial and turbidite systems. p. 3-16. In: Sedimentary Facies in the Active Plate Margin. eds. by A. Taira and F. Masuda. Terra Scientific Publishing Co., Tokyo.
  31. Mutti, E. and W.R. Normark. 1987. Comparing examples of modern and ancient turbidite systems: problems and concepts. p. 1-38. In: Marine Clastic Sedimentology: Concepts and Case Studies. eds. by J.K. Leggett and G.G. Zuffa. Graham & Trotman, London.
  32. Nakajima, T., M. Satoh, and Y. Okamura. 1998. Channel-levee complexes, terminal deep-sea fan and sediment wave fields associated with the Toyama Deep-Sea Channel system in the Japan Sea. Mar. Geol., 147, 25-41. https://doi.org/10.1016/S0025-3227(97)00137-0
  33. Nemec, W. 1990. Aspects of sediment movement on steep delta slopes. p. 29-73. In: Coarse-Grained Deltas. eds. by A. Colella and D.B. Prior. International Association of Sedimentologists, Special Publication 10.
  34. Nemec, W. and G. Postma. 1993. Quaternary alluvial fans in southwestern Crete: sedimentation processes and geomorphic evolution. p. 235-276. In: Alluvial Sedimentation. eds. by M. Marzo and C. Puigdefabregas. IAS Special Publication 17.
  35. Peakall, J., B. McCaffrey, and B. Kneller. 2000. A process model for the evolution, morphology, and architecture of sinuous submarine channels. J. Sediment. Res., 70, 434-448. https://doi.org/10.1306/2DC4091C-0E47-11D7-8643000102C1865D
  36. Scott, K.M. 1966. Sedimentology and dispersal pattern of a Cretaceous flysch sequence, Patagonian Andes, southern Chile. Am. Assoc. Petrol. Geol. Bull., 50, 72-107.
  37. Shultz, A.W. 1984. Subaerial debris flow deposition in the Upper Paleozoic Cutler Formation, western Colorado. J.Sediment. Petrol., 54, 759-772.
  38. Sohn, Y.K., M.Y. Choe, and H.R. Jo. 2002. Transition from debris flow to hyperconcentrated flow in a submarine channel (the Cretaceous Cerro Toro Formation, southern Chile). Terra Nova, 14, 405-415. https://doi.org/10.1046/j.1365-3121.2002.00440.x
  39. Sohn, Y.K., C.W. Rhee, and B.C. Kim. 1999. Debris flow and hyperconcentrated flood-flow deposits in an alluvial fan, NW part of the Cretaceous Yongdong Basin, central Korea. J. Geol., 107(1), 111-132. https://doi.org/10.1086/314334
  40. Todd, S.P. 1989. Stream-driven, high-density gravelly traction carpets: possible deposits in the Trabeg Conglomerate Formation, SW Ireland and some theoretical considerations of their origin. Sedimentology, 36, 513-530. https://doi.org/10.1111/j.1365-3091.1989.tb02083.x
  41. Todd, S. and D. Went. 1991. Lateral migration of sand-bed rivers: examples from the Devonian Glashabeg Formation, SW Ireland and the Cambrian Alderney Sandstone Formation, Channel Islands. Sedimentology, 38, 997-1020. https://doi.org/10.1111/j.1365-3091.1991.tb00368.x
  42. Vallance, J.W. and K.M. Scott. 1997. The Osceola Mudflow from Mount Rainier: Sedimentology and hazard implications of a huge clay-rich debris flow. Geol. Soc. Am. Bull., 109, 143-163. https://doi.org/10.1130/0016-7606(1997)109<0143:TOMFMR>2.3.CO;2
  43. Wilson, T.J. 1991. Transition from back-arc to foreland basin development in the southernmost Andes. Geol. Soc. Am. Bull., 103, 98-111. https://doi.org/10.1130/0016-7606(1991)103<0098:TFBATF>2.3.CO;2
  44. Winn, R.D. Jr. and R.H. Dott, Jr. 1977. Large-scale tractionproduced structures in deep-water fan-channel conglomerates in southern Chile. Geology, 5, 41-44. https://doi.org/10.1130/0091-7613(1977)5<41:LTSIDF>2.0.CO;2
  45. Winn, R.D. Jr. and R.H. Dott, Jr. 1979. Deep-water fanchannel conglomerates of Late Cretaceous age, southern Chile. Sedimentology, 26, 203-228. https://doi.org/10.1111/j.1365-3091.1979.tb00351.x
  46. Wonham, J.P., S. Jayr, R. Mougamba, and P. Chuilon. 2000. 3D sedimentary evolution of a canyon fill (Lower Miocene-age) from the Mandorove Formation, offshore Gabon. Mar. Petrol. Geol., 17, 175-197. https://doi.org/10.1016/S0264-8172(99)00033-1
  47. Wynn, R.B., D.G. Masson, D.A.V. Stow, and P.P.E. Weaver. 2000. Turbidity current sediment waves on the submarine slopes of the western Canary Islands. Mar. Geol.,163, 185-198. https://doi.org/10.1016/S0025-3227(99)00101-2
  48. Wynn, R.B., D.J.W. Piper, and M.J.R. Gee. 2002. Generation and migration of coarse-grained sediment waves in turbidity current channels and channel-lobe transition zones. Mar. Geol., 192, 59-78. https://doi.org/10.1016/S0025-3227(02)00549-2

Cited by

  1. Cretaceous slab segmentation in southwestern Gondwana vol.147, pp.02, 2010, https://doi.org/10.1017/S0016756809990355