DOI: 10.1016/j.quascirev.2015.05.015
Scopus记录号: 2-s2.0-84930932715
论文题名: Lake Qinghai sediment geochemistry linked to hydroclimate variability since the last glacial
作者: Jin Z. ; An Z. ; Yu J. ; Li F. ; Zhang F.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2015
卷: 122 起始页码: 63
结束页码: 73
语种: 英语
英文关键词: Asian dust
; Ca2+-limited lake water
; Hydroclimate
; Lacustrine precipitate
; Lake Qinghai
; Sediment geochemistry
Scopus关键词: Animals
; Arid regions
; Calcium
; Carbonate minerals
; Dust
; Geochemistry
; Glacial geology
; Lakes
; Minerals
; Precipitates
; Rubidium
; Sedimentology
; Asian dust
; Hydroclimate
; Lake Qinghai
; Lake waters
; Sediment geochemistries
; Sediments
; aragonite
; calcium carbonate
; chemical composition
; climate variation
; eolian process
; lacustrine deposit
; Last Glacial
; Northern Hemisphere
; ostracod
; paleoclimate
; sediment chemistry
; semiarid region
; shell
; China
; Qinghai
; Qinghai Lake
; Ostracoda
英文摘要: Geochemistry of basin sediments from semi-arid regions is valuable to understand past hydroclimatic changes. Here, we investigate the links of sedimentary geochemistry (Rb, Sr, Ca/Zr, TOC, and %CaCO3 ), carbonate mineralogy and ostracod shell δ18O of Lake Qinghai, a basin proximal to major dust production centers at mid-latitudes of the Northern Hemisphere, to changes in depositional conditions and hydroclimate during the past 32ka. Surface lacustrine sediments are characterized by low-Rb, high-Sr, low-Rb/Sr, high-%CaCO3 and high-Ca/Zr values, in contrast to the chemical compositions of eolian loess (high-Rb, low-Sr, high-Rb/Sr, low-%CaCO3 , and low-Ca/Zr). A direct comparison of soluble Ca and Sr in two short cores with instrumental water discharge data suggests that lacustrine precipitates in Lake Qinghai are dominated by authigenic aragonite formed under Ca2+-limited water conditions, and that the accumulation rate of aragonite dominantly depends on solute fluxes into the lake during the rainy seasons (late May to September). Our high-resolution down-core records show that sediments during the last glacial (~32-19.8ka) had high-Rb, low-Sr, low-%CaCO3 , and low-Ca/Zr, indicating eolian dust (loess) accumulation in a desiccated basin under dry glacial conditions, further supported by grain size and pollen results. This type of sedimentation was maintained during the last deglacial (~19.8-11.5ka), but interrupted by episodic lacustrine precipitates with high-Sr, high-%CaCO3 , high-Ca/Zr, and low-Rb. At ~11.5ka, sedimentary Rb/Sr, Ca/Zr, %CaCO3 and TOC show dramatic and permanent changes, implying an abrupt shift in the atmospheric circulation at the onset of the Holocene in the Lake Qinghai region. Lacustrine precipitates have persisted throughout the Holocene with a maximum during the early to mid-Holocene (~10.5-8.0ka). Since ~8.0ka, the gradual and significant decreases in aragonite and Sr accumulations in tandem with increasing dust deposit and more positive ostracod δ18O may be linked to a weakening of Asian summer monsoons during the mid-to-late Holocene. Overall, our records appear to show a high sensitivity of sediment development and geochemistry in Lake Qinghai to the regional hydroclimate changes since the last glacial. © 2015 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59890
Appears in Collections: 过去全球变化的重建
There are no files associated with this item.
作者单位: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China; Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an, China; Research School of Earth Sciences, The Australian National University, Canberra, ACT, Australia; College Resources and Environmental Science, Nanjing Agricultural University, Nanjing, China
Recommended Citation:
Jin Z.,An Z.,Yu J.,et al. Lake Qinghai sediment geochemistry linked to hydroclimate variability since the last glacial[J]. Quaternary Science Reviews,2015-01-01,122