Hostname: page-component-78c5997874-4rdpn Total loading time: 0 Render date: 2024-11-02T16:07:32.076Z Has data issue: false hasContentIssue false
  • English
  • Français

The ratio of mechanical to chemical denudation in alluvial systems, derived from geochemical mass balance

Published online by Cambridge University Press:  03 November 2011

A. D. Stewart
A. D. Stewart
Affiliation:
A. D. Stewart, Postgraduate Research Institute for Sedimentology, University of Reading, Reading RG62AB
Get access Rights & Permissions [Opens in a new window]

Abstract

Mass balance equations are derived which link the ratios Ts/ (suspended load/dissolved load from chemical weathering) and Tb/Ts (bed load/suspended load), with any two geochemical components present in the source rock and the alluvial system. If the dissolved load is unknown the ratios can be estimated from the relatively insoluble silica and alumina. The ratio Ts/, which for large river basins depends on climate and relief, can thus potentially be determined from ancient alluvial sequences.

The equations help define the source composition of a group of 13 modern rivers for which Ts, and alluvial geochemistry are known. These rivers together drain 27% of the continental surface. For a source area with the average continental sandstone to shale ratio of 0·6 the observed average value of Ts/ is obtained when limestone, sandstone and shale are present in the proportions 6·7:21·6:35·7. The figure of 64% sediment in the source area is very similar to the 66% determined by Blatt and Jones (1975) from geological maps of the continents. The equations also show that average bed load transport rate into these 13 basins is about 27% of total transport, and into the Amazon basin about 37%. Bed load transport rates out of the basins, into the sea, are relatively very small.

Keywords

Chemical denudationpalaeoclimatealluvial geochemistryalluvial bed load transport rate
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 84 , Issue 1 , 1993 , pp. 73 - 78
Copyright
Copyright © Royal Society of Edinburgh 1993

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

Alekin, O. A. & Brazhnikova, L. V. 1964. Relation between dissolved and suspended loads of streams. DOKL AKAD NAUK SSSR 146, 170–172 (in translation).Google Scholar
Allen, J. R. L. 1985. Principles of physical sedimentology, 1–272. London: Allen & Unwin.Google Scholar
Blatt, H. & Jones, R. L., 1975. Proportions of exposed igneous, metamorphic, and sedimentary rocks. BULL GEOL SOC AM 86, 1085–88.2.0.CO;2>CrossRefGoogle Scholar
Brotzen, O. 1966. The average igneous rock and the geochemical balance. GEOCHIM COSMOCHIM ACTA 30, 863–8.CrossRefGoogle Scholar
Clarke, F. W. 1924. The data of geochemistry. BULL US GEOL SURV 770, 1–841.Google Scholar
Franzinelli, E. & Potter, P. E. 1983. Petrology, chemistry and texture of modern river sands, Amazon river system. J GEOL 91, 23–39.CrossRefGoogle Scholar
Holland, H. D. 1984. The chemical evolution of the atmosphere and oceans, 1–582. Princeton: Princeton Univ. Press.Google Scholar
Martin, J. M. & Meybeck, M. 1979. Elemental mass-balance of material carried by world major rivers. MARINE CHEM 7, 173–206.CrossRefGoogle Scholar
Meybeck, M. 1977. Dissolved and suspended matter carried by rivers: composition, time and space variations, and world balance. In Golterman, H. L. (ed.) Interactions between sediments and fresh waters, 25–32. The Hague: Junk.Google Scholar
Meybeck, M. 1979. Concentrations des eaux fluviales en éléments majeurs et apports en solution aux océans. REV GEOL DYNAM GEOG PHYS 21, 215–46.Google Scholar
Meybeck, M. 1981. Pathways of major elements from land to ocean through rivers. In Martin, J. M., Burton, J. D. & Eisma, D. (eds) River input to the ocean system, 18–30. UNEP/UNESCO.Google Scholar
Meybeck, M. 1988. How to establish and use world budgets of riverine materials. In Lerman, A. & Meybeck, M. (eds) Physical and chemical weathering in geochemical cycles, 247–72. Dordrecht: Kluwer.CrossRefGoogle Scholar
Pettijohn, F. J. 1975. Sedimentary rocks. 3rd edn, 1–628. New York: Harper & Row.Google Scholar
Pettijohn, F. J., Potter, P. E. & Siever, R. 1987. Sand and sandstone. 2nd edn, 1–553. New York: Springer Verlag.CrossRefGoogle Scholar
Potter, P. E. 1978. Petrology and chemistry of modern big river sands. J GEOL 86, 423–49.CrossRefGoogle Scholar
Ronov, A. B. 1964. Common tendencies in the chemical evolution of the Earth's crust, ocean and atmosphere. GEOCHEM INT 4, 713–37.Google Scholar
Ronov, A. B. & Migdisov, A. A. 1971. Geochemical history of the crystalline basement and the sedimentary cover of the Russian and North American platforms. SEDIMENTOLOGY 16, 137–185.CrossRefGoogle Scholar
Ronov, A. B., Mikhailovskaya, M. S. & Solodkova, I. I. 1966. Evolution of the chemical and mineralogical composition of arenaceous rocks. In Vinogradov, A. P. (ed.) Chemistry of the Earth's crust, Vol. 1, 212–66. Jerusalem: Israel Program for scientific translations.Google Scholar
Shaw, D. M., Reilly, G. A., Muysson, J. R., Pattenden, G. E. & Campbell, F. E. 1967. An estimate of the chemical composition of the Canadian Precambrian shield. CAN J EARTH SCI 4, 829–53.CrossRefGoogle Scholar
Stallard, R. F. & Edmond, J. M. 1981. Geochemstry of the Amazon, 1. Precipitation chemistry and the marine contribution to the dissolved load at the time of peak discharge. J GEOPHYS RES 86, 9844–58.CrossRefGoogle Scholar
Stallard, R. F. & Edmond, J. M. 1983. Geochemistry of the Amazon, 2. The influence of geology and weathering environment on the dissolved load. J GEOPHYS RES 88, 9671–88.CrossRefGoogle Scholar
Suttner, L. J. & Dutta, P. K. 1986. Alluvial sandstone composition and paleoclimate, I. Framework mineralogy. J SEDIMENT PETROL 56, 329–45.Google Scholar
Veizer, J. 1988. The evolving exogenic cycle. In Gregor, C. B., Garrels, R. M., MacKenzie, F. T. & Maynard, J. B. (eds) Chemical cycles in the evolution of the Earth, 175–220. New York: Wiley.Google Scholar
Veizer, J. & Jansen, S. L. 1985. Basement and sedimentary recycling, 2. Time dimension to global tectonics. J GEOL 93, 625–43.CrossRefGoogle Scholar
Walling, D. E. & Webb, B. W. 1983a. The dissolved loads of rivers; a global overview. PUBL INT ASSOC HYDROL SCI 141, 3–20.Google Scholar
Walling, D. E. & Webb, B. W. 1983b. Patterns of sediment yield. In Gregory, K. J. (ed.) Background to palaeohydrology, 69–100. Chichester: Wiley.Google Scholar