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The Scientific World Journal
Volume 2014, Article ID 742950, 13 pages
Research Article

Geochemical Mass Balance and Elemental Transport during the Weathering of the Black Shale of Shuijingtuo Formation in Northeast Chongqing, China

1Department of Geological Engineering, Southwest Jiaotong University, Chengdu 611756, China
2Moe Key Laboratory of High-Speed Railway Engineering, Southwest Jiaotong University, Chengdu 610031, China
3School of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China

Received 22 February 2014; Revised 15 July 2014; Accepted 17 July 2014; Published 13 August 2014

Academic Editor: Sandow M. Yidana

Copyright © 2014 Sixiang Ling et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


An understanding of the processes that control the behavior of major elements with respect to weathering profile is essential to calculate the mobility, redistribution, and mass fluxes of elements. Hence, this study aims to determine the geochemical mass balance, strain, elemental correlation, and transport in weathering profiles. We constructed three weathering profiles for the black shale of Shujingtuo formation. As per the principal component analysis of major elements, density, and pH values, the first component represents the “elemental factor” and the second denotes the “external factor.” The “depletion” pattern is a mass transportation pattern, and Na, K, and Mg are depleted along transect relative to the composition of fresh rock. Fe is redeposited at the bottom half of the saprock zone, whereas Al is accumulated at the regolith zone. The Fe and Al patterns are attributed to the “depletion–addition” and “addition” patterns, respectively. The strain in profiles A and B demonstrates the expansion at the regolith zone and part of the saprock zone. In profile C, however, these zones collapsed at all depths. In chemical weathering, Na, K, Ca, Mg, and Si are depleted in the following order: valley (C) > near mountaintop (B) > ridge (A).