The paleoenvironmental significance of spatial distributions of grain size in groundwater‐recharged lakes: A case study in the hinterland of the Badain Jaran Desert, northwest China

Abstract

For lakes in desert hinterlands that are not recharged by river runoff, sediment input solely comes from wind transport. While the processes of sediment transport and deposition in these lakes differ significantly from those with river discharge, the spatial distribution of sediment grain size in these groundwater‐recharged lakes remains largely unknown. Moreover, whether the grain size distribution in these lake sediments can be used as a proxy in the study of past climatic change and environmental evolution studies is unclear. In this study, five lakes with a range of surface areas that had no runoff recharge were selected from the hinterland of the Badain Jaran Desert of north‐western China, and a total of 108 samples of lake surface sediments were collected to examine the spatial distribution of grain size. Moreover, an end‐member‐modeling algorithm was used to calculate end members from all grain size measurements. Our results showed that both the median and mean grain sizes in the lake sediments decreased from the nearshore to the offshore, deep‐water zone. However, the lowest median and mean grain sizes were not found in the center of the lakes, in contrast to lakes recharged by surface runoff. The median grain size of sediment in the lake center was negatively correlated with lake level, and thus could help reveal lake evolution at low resolutions. Moreover, EM1 and EM2 were interpreted as wind transported sediment, and sediment perturbed by lake waves after wind transport, respectively. The modal grain size of EM1 varied slightly between lakes, while changes in the modal grain size of EM2 were related to lake area. Given the positive relationship found between EM2 content and lake level, changes in the EM2 content (%) can serve as a rough indicator of lake level fluctuations at low temporal resolutions. Copyright © 2017 John Wiley & Sons, Ltd.

Total organic carbon and its environmental significance for the surface sediments in groundwater recharged lakes from the Badain Jaran Desert, northwest China

“…Thus, it is an ideal region for studying changes in climate at different time scales (Yang and Scuderi, 2010;Li et al, 2016c;Wang et al, 2016). however, for lakes in the hinterland of deserts, which are not recharged by river runoff, sediment is only transported by the wind (Li et al, 2018). Thus, allochthonous organic matter (oM) transport and deposition processes differ from those in lakes with river discharge.…”

Environmental Significance of the Chemical Composition of Sediments in Groundwater‐Recharged Lakes of the Badain Jaran Desert, NW China

“…Previous studies indicated that there was no surface flow supply to the lakes (Dong et al, ; Ma et al, ). Ning et al () suggested that the median size of the surface eolian sand was quite stable, with a mean value of 270 μm in this region, and the surface eolian sand can be transported to the lake by saltation at the present wind velocities (Z. Li et al, ). Furthermore, the median grain size of the sediment ranges between 111 and 189 μm in the five lakes, and more than 70% of these lake sediments are composed of sand, which have frequency curves of the grain‐size distribution similar to that of the eolian sand (Z. Li et al, ).…”

“…Previous studies suggested that the lake sediment chemistry not only reveals the characteristics of the bedrock but also is affected by climate and weathering in the watershed when detrital material is transported by runoff into lakes in arid regions (Sahoo et al, ; Zhong et al, , ). Moreover, sediment transported and deposited into a lake is influenced by runoff, wind forces (N. Wang et al, ), hydrodynamic forces, and hydrochemistry (Bogen et al, ; Dietze et al, ; Z. Li et al, ). Thus, spatial and temporal variations in the lake sediment chemistry result from multiple processes and can have complicated environmental significance (Jin et al, ; Margalef et al, ; Xu et al, ).…”

“…For lakes in the hinterlands of hyperarid desert regions, which are not recharged by river runoff, sediment is transported only by wind (Dong et al, ; Z. Li et al, ). Thus, the sediment transport and deposition processes in such water bodies differ from those in lakes with surface runoff; it remains uncertain whether the sediment chemistry of such desert lakes is affected by multiple processes, such as the sediment source, eolian transport, weathering, and the physical and chemical characteristics of the lake itself.…”

“…Thus, the sediment transport and deposition processes in such water bodies differ from those in lakes with surface runoff; it remains uncertain whether the sediment chemistry of such desert lakes is affected by multiple processes, such as the sediment source, eolian transport, weathering, and the physical and chemical characteristics of the lake itself. Previous studies discussed the paleoenvironmental significance of the spatial distributions of grain size and total organic carbon (Dong et al, ; Z. Li et al, ). Compared to lakes with surface runoff, the mechanisms controlling the spatial variability of sediment chemistry in closed‐basin desert lakes remain unclear.…”