n-Alkanes and compound carbon isotope records from Lake Yiheshariwusu in the Hulun Buir sandy land, northeastern China

Abstract

The Hulun Buir sandy land in northern China is located at the northern limit region of the East Asian summer monsoon (EASM) and is therefore sensitive to the extension of the front of the rainfall belt. Here we report an n-alkane and compound-specific carbon isotope record from the Holocene sediments of Lake Yiheshariwusu in the middle of the Hulun Buir sandy land. The sediments contain a suite of n-alkanes with a strong odd over even carbon number predominance, with the maximum contribution from nC31, which is a typical distribution in grassland regions. The low temperatures in this cold region greatly limit the growth of C4 plants and thus the long-chain n-alkanes in lake sediments are mainly derived from leaf wax lipids of C3 plants growing within the sandy land. In this C3-vegetation-dominated region, the δ13C27–33 value (weighted carbon isotope values of nC27– nC33) are regulated mainly by the physiological and biochemical responses of plants to water stress and are therefore interpreted as a proxy of effective precipitation or humidity. The δ13C27–33 time series shows a trend of gradually decreasing values that suggests an increase in effective precipitation since 8.5 ka (1 ka = 1000 cal yr BP). Relative droughts occurred during the intervals of 6.3–5.5, 4.1–3.6 ka, and during the last 200 years. In addition, the δ13C27–33 time series and comparable paleoenvironmental records from neighboring sites suggest opposite trends of summer monsoon rainfall between northeastern and southeastern China. We suggest that a coupled process between low and high latitudes (the western Pacific Subtropical High and the Okhotsk High) may have played a fundamental role in regulating the shift of the frontal rainfall belt and monsoon rainfall distribution in eastern China during the Holocene.

Meltwater Contribution to Lake Water Budget in Mid‐Latitude Asia During the Deglaciation and Early Holocene

“… (a) Conventional 14 C dates and (b) age models of sediment cores from mid‐latitude Asia. SRM: Lake Sayram (Jiang et al., 2022); QL: Qilian Section (Y. Li et al., 2020); MY: Lake Maloye Yarovoye (Rudaya et al., 2020); EB: Lake Ebeyty (Zhilich et al., 2018); YH: Lake Yihesariwusu (Xie et al., 2020); LGC: Linggo Co (J. Hou et al., 2017); QH: Lake Qinghai (An et al., 2012); YHZ: Lake Yanhaizi (C. T. A. Chen et al., 2003, this study); and DLH: Lake Dalianhai (Wu et al., 2020). Dots indicate normal 14 C ages and triangles indicate anomalously old 14 C ages.…”

“…We here further summarize sediment cores with anomalously old 14 C ages from mid‐latitude Asia (conventional 14 C ages in Figure 3a, and calibrated 14 C ages with reservoir effect considered in Figure 3b), including cores from Qilian Mountain, Lake Dalianhai, and Yihesariwusu in the marginal monsoon region (Y. Li et al., 2020; Wu et al., 2020; Xie et al., 2020), Linggo Co on the central Tibetan Plateau (J. Hou et al., 2017), Lake Maloye Yarovoye and Ebeyty in Western Siberia (Rudaya et al., 2020; Zhilich et al., 2018). All anomalously old 14 C ages from these lakes occur during the deglaciation and early Holocene (Figure 3b), essentially the same as Lake Sayram, Yanhaizi, and Qinghai in this study.…”

“…SRM: Lake Sayram (Jiang et al, 2022); QL: Qilian Section (Y. Li et al, 2020); MY: Lake Maloye Yarovoye (Rudaya et al, 2020); EB: Lake Ebeyty (Zhilich et al, 2018); YH: Lake Yihesariwusu (Xie et al, 2020); LGC: Linggo Co (J. Hou et al, 2017); QH: Lake Qinghai (An et al, 2012); YHZ: Lake Yanhaizi (C. T. A.…”

Spatial patterns of Holocene temperature changes over mid-latitude Eurasia

“…Lake Yihesariwusu (48.13°N, 118.63°E) is a hydrologically closed saline lake located in the center of Hulun Buir dune field, China. The lake is mainly recharged by meteoric precipitation, with an area of ~5 km 2 and a maximum water depth of ~4.0 m 63 . The lake catchment is surrounded by semi-fixed and mobile dunes to the north and sandy land to the south.…”

Leaf wax biomarkers of a high-mountain lake area in western iberia—Implications for environmental reconstructions

“…The relatively high contribution of mid-chain compounds of some shrubs, such as Cytisus sp., (Figure 3; Table 1), highlights that caution is needed when applying distributions n-alkane, such as P aq , to infer past aquatic inputs or lake levels in downcore paleoreconstructions (Xie et al, 2020). However, the relative deviation in the n-alkane distribution of Cytisus sp.…”