On the relationship between αAl indices and the ratios of a number of trace elements – indicators of rock composition in paleo-catchments (on the example of the Riphean and Vendian clay rocks of the Southern and Middle Urals and the Shkapovo-Shikhan depression).
https://doi.org/10.24930/2500-302X-2025-25-5-1023-1040
Abstract
Research subject. Clay rocks (clay siltstones, shales and mudstones) of a number of Riphean stratigraphic units of the Bashkir megaanticlinorium, as well as the Vendian Shkapovo-Shikhan depression and the Kvarkush-Kamennogorsk megaanticlinorium. Methods. Calculation of α Al values based on the data on the bulk chemical composition of clay rocks and the analysis of their correlation links with the ratios (e.g., Th/Sc, (La/Yb)N, etc.) of a number of trace elements that are indicators of rock composition in paleo-catchments. In this case, any statistically significant correlation between the alpha index values and the indicator ratios was considered to be a consequence of the control of the α index values by the rock composition in paleo-catchments, and vice versa. Results. For both relatively small (7–8 analyses) and medium (22 or more analyses) analytical datasets, quite different relationships were established between the α Al indices and the ratios of the elements – indicators of the composition of rocks that make up the paleo-catchments. Conclusions. Similar to many other exospheric lithogeochemical indicators, the use of α indices without analyzing the influence of various factors thereon does not provide correct information on the intensity of weathering
Keywords
Riphean,
Vendian,
Southern Urals,
Middle Urals,
Shkapovo-Shikhan depression,
clay rocks,
α Al E indices,
geochemical indicators of the composition of rock complexes eroded in paleo-catchments
Supporting agencies: The research was supported by the State Contract No. 123011800013-6 of the Institute of Geology and Geochemistry, Ural Branch of RAS
About the Author
A. V. Maslov
A.N. Zavaritsky Institute of Geology and Geochemistry, UB RAS
Russian Federation
Russian Federation
Andrey V. Maslov
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Review
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Maslov A.V. On the relationship between αAl indices and the ratios of a number of trace elements – indicators of rock composition in paleo-catchments (on the example of the Riphean and Vendian clay rocks of the Southern and Middle Urals and the Shkapovo-Shikhan depression). LITHOSPHERE (Russia). 2025;25(5):1023-1040. (In Russ.) https://doi.org/10.24930/2500-302X-2025-25-5-1023-1040
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