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<p>Climate warming and increased precipitation across the Qinghai-Xizang Plateau (QXP) have caused lake expansion, posing a threat to the safety of local infrastructure and ecosystems. Grain size in lake sediments is a reliable proxy for elucidating hydrological variations in these lakes. However, diverse sources of clastic fractions in lake sediments complicate the interpretation of hydrological changes based on grain-size records. We analyzed 94 surface-sediment samples from Hurleg and Toson lakes, the largest lake system of the Qaidam Basin, northeastern QXP, and explored the grain-size spatial distribution and its hydrological significance. Results demonstrate that fine silt (4–16 µm) is predominant in both lakes, followed by medium to coarse silt (16–63 µm), and clay (&lt;4 µm), while sand (&gt;63 µm) fraction was the least abundant. Using the end-member analysis (EMA), we identified three end-members in Hurleg Lake (HEM1–HEM3) and four in Toson Lake (TEM1–TEM4). In Hurleg Lake, HEM1 and HEM2 mainly come from fluvial deposits from the Bayin River. HEM3 mainly comes from surface runoff and shoreline erosion. In Toson Lake, TEM1 represents typical lacustrine sediments, and TEM2 represents fine-grained terrestrial residual and gully input components. TEM3 originates mainly from aeolian transport and terrestrial residual. TEM4 is a dominant component of the subaqueous alluvial fan. Single-specimen unmixing suggested a differentiation between aeolian inputs and hydrodynamically sensitive components. Fine silt components (mode size 4.0–14.5 µm) are likely related to lake-level variations, whereas coarser silt components (mode size 18.7–51.8 µm) indicate regional dust activity. Notably, in Toson Lake, the fluvial sand components (mode size 66.9–111.5 µm) that were likely derived from western gully runoff, may represent a potential indicator of extreme hydrological events in the Qaidam Basin. These findings provide robust constraints on modern sedimentary processes for reconstructing the history of hydroclimatic changes using grain-size records in the northeastern QXP.</p>

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Hydrology and sediment supply in the largest lake system of Qaidam Basin, northeastern Qinghai-Xizang Plateau: insights from surface-sediment grain size

  • 期刊论文

  • 发表日期：

    2026年4月8日

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  • Hongyu Li,
  • Haicheng Wei,
  • Aiying Cheng,
  • Chunliang Gao,
  • Chenyu Wang,
  • Ronglei Duan,
  • Shun Wang,
  • Hongpan Xue

摘要

Climate warming and increased precipitation across the Qinghai-Xizang Plateau (QXP) have caused lake expansion, posing a threat to the safety of local infrastructure and ecosystems. Grain size in lake sediments is a reliable proxy for elucidating hydrological variations in these lakes. However, diverse sources of clastic fractions in lake sediments complicate the interpretation of hydrological changes based on grain-size records. We analyzed 94 surface-sediment samples from Hurleg and Toson lakes, the largest lake system of the Qaidam Basin, northeastern QXP, and explored the grain-size spatial distribution and its hydrological significance. Results demonstrate that fine silt (4–16 µm) is predominant in both lakes, followed by medium to coarse silt (16–63 µm), and clay (<4 µm), while sand (>63 µm) fraction was the least abundant. Using the end-member analysis (EMA), we identified three end-members in Hurleg Lake (HEM1–HEM3) and four in Toson Lake (TEM1–TEM4). In Hurleg Lake, HEM1 and HEM2 mainly come from fluvial deposits from the Bayin River. HEM3 mainly comes from surface runoff and shoreline erosion. In Toson Lake, TEM1 represents typical lacustrine sediments, and TEM2 represents fine-grained terrestrial residual and gully input components. TEM3 originates mainly from aeolian transport and terrestrial residual. TEM4 is a dominant component of the subaqueous alluvial fan. Single-specimen unmixing suggested a differentiation between aeolian inputs and hydrodynamically sensitive components. Fine silt components (mode size 4.0–14.5 µm) are likely related to lake-level variations, whereas coarser silt components (mode size 18.7–51.8 µm) indicate regional dust activity. Notably, in Toson Lake, the fluvial sand components (mode size 66.9–111.5 µm) that were likely derived from western gully runoff, may represent a potential indicator of extreme hydrological events in the Qaidam Basin. These findings provide robust constraints on modern sedimentary processes for reconstructing the history of hydroclimatic changes using grain-size records in the northeastern QXP.