Hostname: page-component-8448b6f56d-xtgtn Total loading time: 0 Render date: 2024-04-19T22:29:09.648Z Has data issue: false hasContentIssue false

Origin of illite in the loess from the Luochuan area, Loess Plateau, Central China

Published online by Cambridge University Press:  09 July 2018

Junfeng Ji
Affiliation:
Department of Earth Sciences, State Key Laboratory of Mineral Deposit Research, Nanjing University, Nanjing 210093, China
Jun Chen
Affiliation:
Department of Earth Sciences, State Key Laboratory of Mineral Deposit Research, Nanjing University, Nanjing 210093, China
Huayu Lu
Affiliation:
Xi'an Laboratory of Loess and Quaternary Geology, Academia Sinica, Xi'an, 710061, China

Abstract

Illite, the predominant component of the clay fraction of the Chinese loess, has been studied by X-ray diffraction (XRD) in 33 samples taken from the Holocene palaeosol (S0), the last glacial loess (L1) and the last interglacial palaeosol (S1) in the Louchuan loess section of the Loess Plateau in China. The XRD investigations indicate that it is mainly a 2M1 dioctahedral mineral with crystallinity values ranging from 0.23 to 0.36°Δ2θ (CIS Index). The 2M1 polytype illites with low IC values preclude a pedogenic formation of illites in the surface horizons of aridic and semi-aridic soils or deserts, and thus the clay mineral composition was largely determined by provenance. The illites are considered to be of detrital origin derived from pre-existing sediments and very low- to low-grade metamorphic rocks, eroded from the northern part of the Tibetan Plateau. The clay content of the loess and palaeosols was largely controlled by the strength of the winter monsoon, rather than by effects of in situ pedogenetic processes.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1999

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

An, Z.S. & Porter, S.C. (1997) Millennial-scale climate oscillations during the last interglaciation in central China. Geology, 25, 603606.Google Scholar
An, Z.S., Kukla, G.J., Porter, S.C. & Xiao, J.L. (1991) Magnetic suscptibility evidence of monsoon variation on the Loess Plateau of central China during the last 130 000 years. Quat. Res. 36, 2936.Google Scholar
An, Z.S., Liu, T.S., Lu, Y.C., Kukla, G., Wu, X.H. & Hua, Y.M. (1990) The long-term paleomonsoon variation recorded by the loess-paleosol sequence in central China. Quat. Int. 7/8, 9195.Google Scholar
Bronger, A. & Heinkele, T. (1990) Mineralogical and clay mineralogical aspects of loess research. Quat. Int. 7/8, 3752.Google Scholar
Brown, G. & Brindley, G.W. (1980) X-ray diffraction procedures for clay mineral identification. Pp. 305—360 in: Crystal Structures of Clay Minerals and their X-ray Identification (Brindley, G.W. & Brown, G., editors). Mineralogical Society, London.Google Scholar
Forman, S.L. (1991) Late Pleistocene chronology of loess deposition near Luochuan, China. Quat. Res. 36, 1928.Google Scholar
Ji, J.F., Chen, I. & Lu, H.Y. (1999) Origin of illite in the Luochuan loess section: evidence from TEM study. Chin. Sci. Bull. 44, 372375.Google Scholar
Jia, C.Z., editor (1997) Tectonic Characteristics and Petroleum, Tarim Basin, China. Pp. 81 — 106. Petroleum Industry Press, Beijing.Google Scholar
Kisch, H.J. (1991) Illite crystallinity: recommendations on sample preparation, X-ray diffraction settings, and interlaboratory samples. J. metam. Geol. 9, 665670.Google Scholar
Kukla, G. & An, Z.S. (1989) Loess stratigraphy in central China. Palaeogeog. Palaeoclim. Palaeoecol. 72, 203225.Google Scholar
Levinson, A.A. (1955) Studies in the mica group: polymorphism among illites and hydrous micas. Am. Miner. 40, 4149.Google Scholar
Liu, C.Q., Masuda, A., Okada, A., Yabuki, S. & Fan, Z.L. (1994) Isotope geochemistry of Quaternary deposits from the arids lands in northern China. Earth Planet. Sci. Lett. 127, 2538.CrossRefGoogle Scholar
Liu, T.S. and 30 others (1985) Loess and the Environment. China Ocean Press, Beijing.Google Scholar
Martinson, D.G., Pisias, N.G., Hays, J.D., Imbrie, J., Moore, T.C. Jr. & Shackleton, N.J. (1987) Age dating and the orbital theory of the ice ages: development of a high-resolution 0 to 300,000-year chronostratigraphy. Quat. Res. 27, 129.Google Scholar
Maxwell, D.T. & Hower, J. (1967) High-grade diagenesis and low-grade metamorphism of illite in the Precambrian Belt series. Am. Miner. 52, 843857.Google Scholar
Moore, D.M. & Reynolds, R.C. Jr. (1989) X-ray Diffraction and the Identification and Analysis of Clay Minerals. Oxford Univ. Press, Oxford.Google Scholar
Reynolds, R.C. Jr. (1963) Potassium-rubidium ratios and polymorphism in illites and microclines from the clay size fractions of Proterozoic carbonate rocks. Geochim. Cosmochim. Ada, 27, 10971112.Google Scholar
Singer, A. (1988) Illite in aridic soils, desert dusts and desert loess. Sedim. Geol. 59, 251259.Google Scholar
Singer, A. (1989) Illite in the hot-aridic soil environment. Soil Sci. 147, 126133.Google Scholar
Środoń, J. & Eberl, D.D. (1984) Illite. Pp. 495-544 in: Micas (Bailey, S.W., editor). Reviews in Mineralogy, 13, Mineralogical Society of America, Washington D.C.Google Scholar
Velde, B. (1965) Experimental determination of muscovite polymorphs stabilities. Am. Miner. 50, 436449.Google Scholar
Wang, H. (1986) The tectonic framework and the geotectonic units. Pp. 237—255 in: The Geology of China (Yang, Z., Cheng, Y. & Wang, H., editors). Clarendon, Oxford.Google Scholar
Warr, L.N. & Rice, A.H.N. (1994) Interlaboratory standardization and calibration of clay mineral crystallinity and crystallite size data. J. metam. Geol. 12, 141152.Google Scholar
Weaver, C.E. & Broekstra, B.R. (1984) Illite-mica. Pp. 67—199 in: Shale Slate Metamorphism in Southern Appalachians. Weaver, C.E. & Associates, Elsevier, Amsterdam.Google Scholar
Yoder, H.S. & Eugster, H.P. (1955) Synthetic and natural muscovites. Geochim. Cosmochim. Ada, 8, 225280.Google Scholar
Yoder, H.S. (1959) Experimental studies on micas: a synthesis. Clays Clay Miner. 6, 4260.Google Scholar