title: Geochemical mass balance and elemental transport during the weathering of the black shale of Shuijingtuo formation in Northeast Chongqing, China.
abstract: 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).
authors.affiliation: Department of Geological Engineering, Southwest Jiaotong University, Chengdu 611756, China.
authors.forename: Sixiang
authors.initials: S
authors.lastname: Ling
authors.affiliation: Department of Geological Engineering, Southwest Jiaotong University, Chengdu 611756, China ; Moe Key Laboratory of High-Speed Railway Engineering, Southwest Jiaotong University, Chengdu 610031, China.
authors.forename: Xiyong
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Geological Engineering, Southwest Jiaotong University, Chengdu 611756, China.
authors.forename: Siyuan
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Department of Geological Engineering, Southwest Jiaotong University, Chengdu 611756, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Liao
authors.affiliation: Department of Geological Engineering, Southwest Jiaotong University, Chengdu 611756, China.
authors.forename: Yong
authors.identifier: 0000-0003-4713-5458
authors.initials: Y
authors.lastname: Ren
authors.affiliation: School of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China.
authors.forename: Baolong
authors.initials: B
authors.lastname: Zhu
mesh_terms: D000535:Aluminum / Q000032:analysis; D002681:China; D019015:Geologic Sediments / Q000737:chemistry*; D005844:Geology; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000032:analysis; D008274:Magnesium / Q000032:analysis; D011188:Potassium / Q000032:analysis; D025341:Principal Component Analysis; D012964:Sodium / Q000032:analysis; D013052:Spectrometry, X-Ray Emission; D014872:Water Movements; D014961:X-Ray Diffraction
chemical_list: D012964:Sodium; D000535:Aluminum; D007501:Iron; D008274:Magnesium; D011188:Potassium