Fragipan Formation within Closed Depressions in Southern Wisconsin, United States

미국 위스콘신 남부지방의 소규모 저습지에 나타나는 이쇄반층(Fragipan)의 형성과정에 관한 연구

  • Park S.J. (Department of Geography, Seoul National University) ;
  • Almond P. (Division of Soil Plant and Ecological Sciences, Lincoln University) ;
  • McSweeney K. (Department of Soil Science, University of Wisconsin) ;
  • Lowery B. (Department of Soil Science, University of Wisconsin)
  • Published : 2006.06.01

Abstract

This study was conducted to determine the pedogenesis of dense subsurface horizons (denoted either Bx or Bd) observed within closed depressions and in toeslope positions at loess-covered glacial tillplains in southern Wisconsin. Some of these dense subsurface horizons, especially those occurring within depressions, show a close morphological resemblance to fragipans elsewhere, even though the existence of fragipans has not been previously reported in southern Wisconsin. The spatial occurrence of fragipans was first examined over the landscape to characterize general soil-landscape relationships. Detailed physico-chemical and micromorphological analyses were followed to investigate the development of fragipans within a closed depression along a catenary sequence. The formation of fragipans at the study site is a result of sequential processes of physical ripening and accumulation of colloidal materials. A very coarse prismatic structure with a closely packed soil matrix was formed via physical ripening processes of loess deposited in small glacial lakes and floodplains that existed soon after the retreat of the last glacier. The physically formed dense horizons became hardened by the accumulation of colloidal materials, notably amorphous Si. The accumulation intensity of amorphous Si varies with mass balance relationships, which are governed by topography and local drainage conditions. Well-developed Bx horizons evolve at closed depressions where net accumulation of amorphous Si occurs, but the collapsed layers remain as Bd horizons at other locations where soluble Si has continuously been removed downslope or downvalley. Hydromorphic processes caused by the presence of fragipans are degrading upper parts of the prisms, resulting in the formation of an eluvial fragic horizon (Ex).

이 연구는 미국 위스콘신 남부지방의 뢰스(loess)로 덮여있는 빙퇴석평야상의 소규모 저습지와 산록부에서 관찰되는 치밀차표층(dense subsurface horizons)의 형성원인과 형성과정을 설명하기 위한 것이다. 연구대상이 된 치밀차표층은 Bd 혹은 Bx층으로 명명될 수 있는 토양층이다. 일부 치밀차표층은 형태적으로 이쇄반층(fragipan, Bx)과 매우 유사한 특징을 보이지만, 아직까지 주변지역에서 이쇄반층의 존재가 보고된 바는 없다. 이 연구에서는 치밀차표층과 이쇄반층의 상대적인 분포의 차이를 지형기복과의 관계를 통해 관찰하였으며, 그 형성원인을 파악하기 위해 물리 화학적 분석과 더불어 토양구조의 현미경 관찰을 실시하였다. 그 결과 이쇄반층의 형성은 토양구조의 물리적인 숙성과정(physical ripening)과 그에 이은 콜로이드물질의 집적과정을 거치면서 형성된 것으로 결론을 내렸다. 치밀차표층에서 관찰되는 높은 밀도의 토양매질은 빙하가 물러나면서 형성된 소규모 빙하호수와 범람원에 퇴적된 뢰스물질들이 물리적인 숙성과정(physical ripening)을 거치면서 형성된 것으로 보이며, 그 결과 대규모의 주상구조(prismatic structure)가 형성되었다. 이후 지속적인 토양화과정을 거치면서 Si를 포함하는 콜로이드 물질의 집적에 의해 토양매질이 더욱 단단해지는 과정을 거치게 되면서 이쇄반층으로 발전하게 되었다. Si의 집적정도는 지형적인 특성과 물의 흐름에 의해 결정되게 된다. 물과 물질의 집적이 주로 나타나는 소규모의 저습지에서는 Si의 집적으로 인해 잘 발달된 이쇄반층(Bx)이 발달하게 된다. 반면, Si의 제거가 비교적 활발하게 이루어지는 산록부에서는 이쇄반층의 단계로 발전하지 못하고 치밀층(Bd)에 머물고 있는 것으로 판단된다. 이쇄반층이 만들어진 경우에는 그 상부에 불투수층이 형성되어, 물리적 숙성과정으로 형성된 주상구조의 상부가 서서히 파괴되는 현상을 보기에 된다. 이 경우에는 이쇄반층 상부에 용탈이쇄반층 (eluvial fragic horizon, Ex)이 나타나게 된다.

Keywords

References

  1. Assallay, A.M., I. Jefferson, C.D.F. Rogers, and I.J. Smalley. 1998. Fragipan formation in loess soils: Development of the Bryant hydrocons-olidation hypothesis. Geoderma. 83:1-16 https://doi.org/10.1016/S0016-7061(97)00135-3
  2. Bryant, R.B. 1989. Physical processes of fragipan formation. 141-150. In N.E. Smeck and E.J. Ciolkosz (ed.) Fragipans: Their Occurrence, Classification, and Genesis. SSSA Special Publication. No 24. Soil Science Society of America, Madison, WI
  3. Bullock, P., M.H. Milford and M.G.Cline. 1974. Degradation of argillic horizons in Udalf soils of New York State. Soil Sci. Soc. Am. Proc. 34:621-628
  4. Clayton, L. and J.W. Attig. 1997. Pleistocene geology of Dane country, Wisconsin. Wisconsin Geological and Natural History Survey. Bulletin 95. Madison, WI
  5. Franzmeier, D.P., L.D. Norton and G.C. Sterinhardt. 1989. Fragipan formation in loess of the Midwestern United States. 69-97. In N.E. Smeck and E.J. Ciolkosz (ed.) Fragipans: Their Occurrence, Classification, and Genesis. SSSA Special Publication. No 24. Soil Science Society of America, Madison, WI
  6. Gee, G.W., and J.W. Bauder. 1986. Particle size analysis. 383-412. In A. Klute (ed.) Methods of Soil Analysis; Part 1 Physical and Mineralogical Meth-ods ($2^{nd}$ edition). ASA and SSSA, Madison, WI
  7. Habecker, M.A., K. McSweeney, and F.W. Madison. 1990. Identification and genesis of fragipans in Ochrepts of north central Wisconsin. Soil Sci. Soc. Am. J. 54: 139-146 https://doi.org/10.2136/sssaj1990.03615995005400010022x
  8. Harlan, P.W. and D.P. Franzmeier. 1977. Soil formation on loess in southwestern Indiana: I. Loess stratigraphy and soil morphology. Soil Sci. Soc. Am. J. 41:93-98 https://doi.org/10.2136/sssaj1977.03615995004100010028x
  9. Hesse, P.R. 1968. A Textbook of Soil Chemical Analysis. John Murray, London
  10. Innes, R.P. and D.J. Pluth. 1970. Thin section preparation using epoxy impregnation for petrographic electron probe analysis. Soil Sci. Soc. Am. Proc. 34:483-485
  11. Jha, P.P. and M.G. Cline. 1963. Morphology and genesis of a Sol Brun Acide with fragipan in uniform silty material. Soil Sci. Soc. Am. Proc. 27: 339-344
  12. Karanthanasis, A.D. 1987. Thermodynamic evaluation of amorphous aluminosilicate binding agents in fragipans of Western Kentucky. Soil Sci. Soc. Am. J. 51:819-824 https://doi.org/10.2136/sssaj1987.03615995005100030045x
  13. Karanthanasis, A.D. 1989. Solution chemistry of Fragipan-Thermodynamic approach to understanding fragipan formation. 113-139. In N.E. Smeck and E.J. Ciolkosz (ed.) Fragipans: Their Occurrence, Classification, and Genesis. SSSA Special Publication. No 24. Soil Science Society of America, Madison, WI
  14. Lindbo, D.L. and P.L.M. Veneman. 1989. Fragipans in the Northeastern United States. 11-31. In N.E. Smeck and E.J. Ciolkosz (ed.) Fragipans: Their Occurrence, Classification, and Genesis. SSSA Special Publication. No 24. Soil Science Society of America, Madison, WI
  15. McDaniel, P.A. and A.L. Falen. 1994. Temporal and spatial patterns of episaturation in a Fragixeralf landscape. Soil Sci. Soc. Am. J. 58:1451-1457 https://doi.org/10.2136/sssaj1994.03615995005800050025x
  16. Miller, M.B., T.H. Cooper, and R.H. Rust. 1993. Differentiation of an eluvial fragipan from dense till in northern Minnesota. Soil Sci. Soc. Am. J. 57: 787-796 https://doi.org/10.2136/sssaj1993.03615995005700030027x
  17. Mitchell, M-J. 1978. Soil Survey of Columbia County, Wisconsin. USDA-SCS. U.S. Gov. Print. Office, Washington, DC
  18. Nettleton, W.D., W.D. Daniels and R.J. McCracken. 1968. Two North Carolina coastal plain catenas: I Morphology and fragipan development. Soil Sci. Soc. Am. Proc. 32: 577-582
  19. Norton, L.D. 1986. Erosion-sedimentation in a closed drainage basin in northwest Indiana. Soil Sci. Soc. Am. J. 50: 209-213 https://doi.org/10.2136/sssaj1986.03615995005000010040x
  20. Park, S.J. and T.P. Burt. 1999. Identification of throughflow intensity using the distribution of secondary iron oxides in soils. Geoderma, 93:61-84 https://doi.org/10.1016/S0016-7061(99)00042-7
  21. Park, S.J., McSweeney, K. and Lowery, B. 2001 Identification of the spatial distribution of soils using a process-based terrain characterization. Geoderma, 103:249-272 https://doi.org/10.1016/S0016-7061(01)00042-8
  22. Ray, L.L. 1967. An interpretation of profiles of weathering of the Peorian loess of western Kentucky. U.S. Geol. Surv. Prof. Pap. 576-D:221-227
  23. Samuelson, J.R. 1999. Landscape position and crop sequence impact on surface runoff, drainage, and agriculture chemical leaching. Unpublished M.S. thesis. University of Wisconsin-Madison. 222p
  24. Schoeneberger, P. J., D. A., E. Wysocki, C. Benham and W. D. Broderson. 1998. Field book for describing and sampling soils, Version 1.1. Natural Resources Conservation Service, USDA, National Soil Survey Center, Lincoln, NE
  25. Smeck, N.E. and Ciolkosz, E.J. 1989b. Summary. 151-153. In N.E. Smeck and E.J. Ciolkosz (ed.) Fragipans: Their Occurrence, Classification, and Genesis. SSSA Special Publication. No 24. Soil Science Society of America, Madison, WI
  26. Soil Survey Staff. 1984. Procedures for collecting soil samples and methods of analysis for soil survey. USDA-SCS Soil Surv. Invest. Rep. U.S. Gov. Print. Office, Washington, DC
  27. Soil Survey Staff. 1998. Keys to Soil Taxonomy ($8^{th}$ edition). United States Department of Agriculture, Natural Resources Conservation Service. U.S. Gov. Print. Office, Washington, DC
  28. Soil Survey Staff. 1999. Soil Taxonomy: A Basic System of Soil Classification for Making and Interpreting Soil Surveys ($2^{nd}$ edition). United States Department of Agriculture, Natural Resources Conservation Service. Agriculture Handbook, No. 436
  29. Steinhardt, G.C. and D.P. Franzmeier. 1979. Chemical and mineralogical properties of the fragipans of the Cincinnati catena. Soil Sci. Soc. Am. J. 43:1008-1013 https://doi.org/10.2136/sssaj1979.03615995004300050039x
  30. Walker, P.H. and R.Y. Ruhe 1968. Hillslope models and soil formation, II. Closed systems. Transaction of 9th International Congress of Soil Science. 4:561-568
  31. Witty, J.E. and E.G. Knox 1989. Identification, role in Soil Taxonomy, and worldwide distribution of fragipans. 1-10. In N.E. Smeck and E.J. Ciolkosz (ed.) Fragipans: Their Occurrence, Classification, and Genesis. SSSA Special Publication. No 24. Soil Science Society of America, Madison, WI