Rare Earth Element Patterns in the Karst Terrains of Guizhou Province, China: Implication for Water/Particle Interaction

Abstract

The authors determine the concentrations of dissolved (\0.22 lm) rare earth elements (REE) and suspended particulate matter (SPM) of typical karst rivers in Guizhou Province, China during the high-flow period. The concentrations of acid-soluble REE extracted from SPM using diluted hydrochloric acid are also obtained to investigate water/ particle interaction in the river water. The dissolved REE contents in the river water are extremely low in the rivers of the study. The dissolved REE distribution patterns normalized by the Post Archean Australia Shale (PAAS) in the karst rivers are not flat, show slight enrichment of heavy REE to light REE, and also have significant negative Ce and Eu anomalies. The acid-soluble REE appears to have similar distribution patterns as characterized by MREE enrichment and slight LREE depletion, with unremarkable Ce and Eu anomalies. The PAAS-normalized REE distribution patterns of SPM are flat with negative Eu anomalies. The contents and distribution patterns of REE in the SPM are closely related to the lithological character of the source rocks. The SPM contains almost all the REE produced in the process of surficial weathering. This demonstrates that particle-hosted REE are the most important form of REE occurrence. REE fractionation, which takes place during weathering and transport, leads to an obvious HREE enrichment in the dissolved loads relative to the SPM. Y/Ho ratio can be used to shed light on REE behaviors during water/particle interaction.

Geochemistry of rare earth elements in soils under different land uses in a typical karst area, Guizhou Province, Southwest China

“…Regarding REE migration, some studies have shown that REE are immobile during surface processes (Szczepanski and Ilnicki, 2014). However, some researchers have found that the mobility of REE was controlled by pH values (Han et al, 2009;Pazand and Javanshir, 2014) and REE was generally believed to be mobile at a lower pH value (Han and Liu, 2007;Migaszewski et al, 2014). However, there is In karst regions of the Southwest (SW) China, the degradation of ecosystems has led to many ecological problems, such as Karst Rocky Desertification.…”

Organic Matter Impact on Distribution of Rare Earth Elements in Soil Under Different Land Uses

“…Due to their special electron configuration in the outer shell, Ce and Eu occur as Ce 4+ and Eu 2+ ; the Eu anomaly, that is its deviation from the neighboring elements, is the petrogenesis of rocks in the drainage basin, and that of Ce is due to Ce (III) being oxidized to Ce (IV) during weathering. The two anomalies (Ce and Eu) are defined as follows: where Ce*, La*, Pr*, Eu*, Sm*, and Gd* represent the concentrations of the respective REE in the PAAS. The Ce anomaly and the Eu anomaly represent the deviation of Ce and Eu concentrations from those expected from a linear interpolation of the concentrations of La and Pr and of Sm and Gd, respectively, in the PAAS‐normalized REE patterns of the samples.…”

“…Due to their special electron configuration in the outer shell, Ce and Eu occur as Ce 4þ and Eu 2þ ; the Eu anomaly, that is its deviation from the neighboring elements, is the petrogenesis of rocks in the drainage basin, and that of Ce is due to Ce (III) being oxidized to Ce (IV) during weathering. The two anomalies (Ce and Eu) [31][32][33] are defined as follows:…”

Effects of Soil Properties on K Factor in the Granite and Limestone Regions of China

“…Secondary forest land and shrub land: 45%; agricultural land: 50% Note: MAT, mean annual temperature; MAP, mean annual precipitation. Data were cited from [30][31][32][33][34].…”