| Title | Human-induced changes in sediment properties and amplified endmember differences: Possible geological time markers in the future |
| |
| Author | Yang, Y ; Jia, J;
Zhou, L; Gao, W; Shi, B; Li, Z; Wang, Y P; Gao, S |
| Source | Science of the Total Environment vol. 661, 2019 p. 63-74, https://doi.org/10.1016/j.scitotenv.2019.01.115 |
| Year | 2019 |
| Alt Series | Natural Resources Canada, Contribution Series 20180385 |
| Publisher | Elsevier BV |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf (Adobe® Reader®); html; docx (Microsoft® Word®) |
| Area | Huanghe River; Changjiang River; China |
| Lat/Long WENS | 117.0000 131.0000 40.0000 26.0000 |
| Subjects | hydrogeology; surficial geology/geomorphology; environmental geology; engineering geology; geochemistry; sedimentology; surface waters; rivers; stream sediment samples; dams; sediment properties;
sediment dispersal; grain size analyses; grain size distribution; muds; magnetic properties; stream sediment geochemistry; sediment tracer techniques; marine environments; provenance; currents; Shandong Coastal Current; Northern Jiangsu Coastal
Current; Changjiang Diluted Water; Zhejiang Fujian Coastal Current; Huanghe SeaWarm Current; alluvial sediments; Methodology |
| Illustrations | bar graphs; location maps; tables; plots |
| Released | 2019 01 14 |
| Abstract | Many rivers are facing human-induced system regime shifts that have great environmental, ecological and social implications, necessitating an increasing need to quantify the human influence on sediment
properties and their impacts on the source-to-sink system of marginal seas. The Huanghe and Changjiang Rivers have experienced a dramatic reduction in sediment flux in recent decades, typifying the human influence on sediment properties of global
large rivers. Sediment samples from the two rivers were analyzed to obtain grain size, magnetic and geochemical data. The results show a large difference in sediment properties between pre- and post-dam periods. We applied a discrepancy factor to
re-examine the magnetic and geochemical tracers that were previously used in the two rivers. The discrepancy factors of most magnetic and geochemical tracers in the mud-sized sediments of the two rivers increased by an average of about 109% after dam
construction. This suggests that human-induced changes in sediment properties have greatly improved the discriminatory ability between the sediments from the two rivers. The results also raise the uncertainty of using previous tracers to distinguish
between sediments from the two rivers after damming. Furthermore, significant changes in sediment properties that happened in a relatively short time may provide future geological time markers for sedimentary records with a temporal resolution of
100-101 years. For marine environments, an approach for identifying sediment sources based on multiple independent optimum tracers is also proposed, with composite magnetic (SIRM vs. HIRM) and geochemical (Na2O vs. Zn) tracers being considered. The
results of this work can advance our knowledge of how human activities alter river systems, and identify a sustainable development model under system regime shifts for areas of high-intensity human activity. |
| GEOSCAN ID | 313588 |
|
|