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Simulating Magnetic Susceptibility Profiles in Loess as an Aid in Quantifying Rates of Dust Deposition and Pedogenic Development

Published online by Cambridge University Press:  20 January 2017

Robert S. Anderson  and
Bernard Hallet
Robert S. Anderson
Affiliation:
Department of Earth Sciences, Institute of Tectonics, University of California, Santa Cruz, California, 95064
Bernard Hallet
Affiliation:
Department of Geological Sciences, Quaternary Research Center, University of Washington, Seattle, Washington, 98195
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Abstract

Magnetic susceptibility profiles χ(z) in loess sequences reflect a combination of two climatically modulated processes: dust deposition and pedogenic development. Prominent soils with high χ values, for example, likely reflect periods of slow dust deposition, and warm wet conditions favorable for rapid chemical weathering. To refine our understanding of the climate records contained in loess, we develop a numerical model as a tool for exploring quantitatively the integrated record of the temporal variation in rates of loess aggradation and soil development contained in χ profiles. In our model, the aggrading loess is pedogenically altered in a reactive zone near the ground surface. The strength of the χ signal is dictated by both the depth-dependent intensity of pedogenic processes and the rate of dust accumulation, which dictates the total time a loess parcel spends in the near-surface reactive zone. The model can accommodate both pedogenic production of magnetically susceptible minerals and arrival of magnetically susceptible grains as eolian dust. To explore the model performance and develop a sense of time and length scales implicit in χ profiles, we first examine simple synthetic cases with idealized steady and cyclic climatic forcing. Reported χ profiles in three Chinese loess sequences at varying distances from the western China dust source are then modeled in two illustrative ways: (i) by imposing a specific dust deposition rate history that is proportional to the dust accumulation rate history reported from western Pacific deep-sea cores, allowing the time variation of pedogenic rates to be calculated directly from χ profiles; and (ii) by imposing both dust accumulation and pedogenic rate histories that are independently scaled by the deep-sea δ18O history, which reflects global climate cycles to which regional climate forcing is linked. We find that the zone of pedogenic activity is roughly 0.5–1.0 m thick, both deposition rate and pedogenic intensity have varied dramatically over the last 140,000 yr, the age structure of the Luochuan loess sequence is best fit by driving the model with the δ18O record, and environmental conditions must have been anomalously favorable for pedogenesis during isotope stage 3 at all three sites. Finally, we advocate the assembly of a variety of data types at a suite of sites within any loess field that taken together will better constrain the temporal and spatial patterns of climatically modulated deposition and pedogenic processes.

Type
Research Article
Information
Quaternary Research , Volume 45 , Issue 1 , January 1996 , pp. 1 - 16
Copyright
University of Washington

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References

An, Z. S. Porter, S. C. Weijian, Z. Yanchou, L. Donahue, D. J. Head, M. J. Xihuo, W. Jianzhang, R., and Hongbo, Z. (1993). Episode of strengthened summer monsoon climate of younger Dryas age on the Loess Plateau of central China. Quaternary Research 39 , 45–54.Google Scholar
Banerjee, S. K. (1995). Chasing the paleomonsoon over China: Its magnetic proxy record. GSA Today 5 , 93–97.Google Scholar
Beer, J. Shen, C. Heller, F. Liu, T. Bonani, G. Dittrich, B. Suter, M., and Kubik, P. W. (1993). 10Be and magnetic susceptibility in Chinese loess. Geophysical Research Letters 20 , 57–60.Google Scholar
Brimhall, G. H., and Dietrich, W. E. (1987). Constitutive mass balance relations between chemical composition, volume, density, porosity and strain in metasomatic hydrochemical systems. Geochimica et Cosmochimica Acta 51 , 567–587.Google Scholar
Brimhall, G. H. Lewis, C. J. Ague, J. J. Dietrich, W. E. Hempel, J., and Rix, P. (1988). Metal enrichment in bauxites by deposition of chemically mature aeolian dust. Nature 333 , 819–824.Google Scholar
Brimhall, G. H. Chadwick, O. A. Lewis, C. J. Compston, W. Williams, I. S. Danti, K. J. Dietrick, W. E. Power, M. E. Hendricks, D., and Bratt, J. (1991). Deformational mass transport and invasive processes in soil evolution. Science 255 , 695–702.Google Scholar
Burbank, D. W., and Jijun, L. (1985). Age and paleoclimatic significance of the loess of Lanzhou, North China. Nature 316 , 429–431.Google Scholar
Fahu, C. et al. (1991). Loess stratigraphy of the Lanzhou profile and its comparison to the deep sea sediment and ice core record. GeoJournal 24 , 201–209.Google Scholar
Heller, F., and Liu, T. S. (1982). Magnetostratigraphical dating of loess deposits in China. Nature 300 , 431–433.Google Scholar
Heller, F. Liu, X. M. Liu, T. S., and Xu, T. C. (1991). Magnetic susceptibility of loess in China. Earth and Planetary Science Letters 103 , 301–310.Google Scholar
Heller, F. Shen, C. D. Beer, J. Liu, X. M. Liu, T. S. Bronger, A. Suter, M., and Bonani, G. (1993). Quantitative estimates of pedogenic ferromagnetic mineral formation in Chinese loess and paleoclimatic implications. Earth and Planetary Science Letters 114 , 385–390.Google Scholar
Hovan, S. A. Rea, D. K. Pisias, N. G., and Shackleton, N. J. (1989). A direct link between the China loess and marine 180 records: Aeolian flux to the north Pacific. Nature 340 , 296–298.Google Scholar
Hus, J. J., and Han, J. (1992). The contribution of loess magnetism in China to the retrieval of past global changes—some problems. Physics of the Earth and Planetary Interiors 70 , 154–168.Google Scholar
Imbrie, J., et al. (1984). The orbital theory of Pleistocene climate: Support from a revised chronology of the marine delta 18O record. In “Milancovich and Climate: Part I” (Berger, A. L. et al., Eds.) pp. 169–185. Reidel, Dordrecht.Google Scholar
Kukla, G. Heller, F. Liu, X. M. Xu, T. C. Liu, T. S., and An, Z. S. (1988). Pleistocene climates in China dated by magnetic susceptibility. Geology 16 , 811–814.Google Scholar
Liu, T. S. et al. (1985). “Loess and the Environment,” pp. 162–163. China Ocean Press, Beijing.Google Scholar
Liu, X. Shaw, J. Liu, T. Heller, F., and Yuan, B. (1992). Magnetic mineralogy of Chinese loess and its significance. Geophysical Journal International 108 , 308–310.Google Scholar
Liu, X. Rolph, T. Bloemendal, J. Shaw, J., and Liu, T. (1994). Remanence characteristics of different magnetic grain size categories at Xifeng, central Chinese Loess Plateau. Quaternary Research 42 , 162–165.Google Scholar
Maher, B. A., and Thompson, R. (1991). Mineral magnetic record of the Chinese loess and paleosols. Geology 19 , 3–6.Google Scholar
Maher, B. A., and Thompson, R. (1992). Paleoclimatic significance of the mineral magnetic record of the Chinese loess and paleosols. Quaternary Research 37 , 155–170.Google Scholar
Maher, B. A., and Thompson, R. (1994). Spatial and temporal reconstruction of changes in the Asian palaemonsoon: A new mineral magnetic approach. Earth and Planetary Sciences Letters 125 , 461–471.Google Scholar
Maher, B. A., and Thompson, R. (in press). Paleo-rainfall reconstructions from pedogenic magnetic susceptibility variations in the Chinese loess and paleosols. Quaternary Research .Google Scholar
Nakai, S. Halliday, A. N., and Rea, D. K. (1993). Provenance of dust in the Pacific Ocean. Earth and Planetary Science Letters 119 , 143–157.Google Scholar
Porter, S. C., and An, Z. S. (1995). Correlation between climate events in the North Atlantic and China during the last glaciation. Nature 375 , 305–308.Google Scholar
Pye, K. (1987). “Aeolian Dust and Dust Deposits.” London, Academic Press.Google Scholar
Rea, D. K. (1994). The paleoclimatic record provided by eolian deposition in the deep sea: The geologic record of wind. Reviews of Geophysics 32 , 159–195.Google Scholar
Rea, D. K., and Leinen, M. (1988). Asian aridity and the zonal westerlies: Late Pleistocene and Holocene record of eolian deposition in the northwest Pacific Ocean. Palaeogeography, Palaeoclimatology, Palaeoecology 66 , 1–8.Google Scholar
Rousseau Denis-Didier, , and Kukla, G. (1994). Late Pleistocene climate record in the Eustis Loess section, Nebraska, based on land snail assemblages and magnetic susceptibility. Quaternary Research 42 , 176–187.Google Scholar
TenPas, J. Verosub, K. L. Shumway, R. H., and Singer, M. J. (1995). Evidence for abrupt climate change from the magnetic susceptibility record of a new loess/paleosol section in China. In “Proceedings, International INQUA Congress, Berlin, Germany. August 1995,” p. 272.Google Scholar
Verosub, K. L. Fine, P. Singer, M. J., and TenPas, J. (1994). Pedogenesis and paleoclimate: Interpretation of the magnetic susceptibility record of Chinese loess–paleosol sequences. Geology 21 , 1011–1014.Google Scholar
Verosub, K. L. Fine, P. Singer, M. J., and TenPas, J. (1994). Pedogenesis and paleoclimate: Interpretation of the magnetic susceptibility record of Chinese loess–paleosol sequences. (Reply to comments) Geology 22 , 857–859.Google Scholar
Xiao, J. Porter, S. C. An, Z. Kumai, H., and Yoshikawa, S. (1995). Grain size of quartz as an indicator of winter monsoon strength on the Loess Plateau of central China during the last 130,000 yr. Quaternary Research 43 , 22–29.Google Scholar
Zhou, L. P. Oldfield, F. Wintle, A. G. Robinson, S. G., and Wang, J. T. (1990). Partly pedogenic origin of magnetic mineral variations in Chinese loess. Nature 346 , 737–739. Google Scholar