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Letters
Geology
July 2010 Vol.55 No.20: 2118–2121
doi: 10.1007/s11434-010-3226-0
SPECIAL TOPICS:
High-resolution climate change in mid-late Holocene on Tianchi
Lake, Liupan Mountain in the Loess Plateau in central China and
its significance
ZHOU AiFeng, SUN HuiLing, CHEN FaHu*, ZHAO Yan, AN ChengBang, DONG GuangHui,
WANG ZongLi & CHEN JianHui
Center for Arid Environment and Paleoclimate Research, Key Laboratory of Western China’s Environmental System (Ministry of Education),
Lanzhou 730000, China
Received June 15, 2009; accepted October 30, 2009
According to a core from Tianchi Lake, Liupan Mountain in Loess Plateau sediment, fossil pollen assemblages, magnetic susceptibility (MS) and color scale were measured based on reliable Abies leaf macrofossils radiocarbon chronology. We recovered a
very good high-resolution mid-late Holocene climate change achieve for the transition area of the East Asia monsoon region and
northwest arid region. The results show that the basic climate background was in agreement with the records from cave records in
monsoon regions in eastern China. Besides, it shows more detailed records in abrupt climate change.
high resolution, mid-late Holocene, Tianchi Lake
Citation:
Zhou A F, Sun H L, Chen F H, et al. High-resolution climate change in mid-late Holocene on Tianchi Lake, Liupan Mountain in the Loess Plateau in
central China and its significance. Chinese Sci Bull, 2010, 55: 2118−2121, doi: 10.1007/s11434-010-3226-0
The central-west Chinese Loess Plateau, located in the transition area of the East Asia monsoon region and northwest
arid region, is an ideal region for study on the Holocene
climatic changes, considering its ecological frangibility and
sensitive environmental responses. Asian monsoon variations during the Holocene have been well-documented by
precisely dated cave deposits [1–5]. The general climate
change trend follows changes in summer insolation at low
latitudes of the Northern Hemisphere. Holocene climate
patterns in arid central Asia, controlled mostly by westerly
circulation, show an out-of-phase relationship with Asian
monsoon history [6], which may mainly controlled by North
Atlantic sea-surface temperatures (SSTs), high-latitude air
temperatures that affect the availability, amount and transport
of water vapor and also, topography of the Tibetan Plateau
and adjacent Asian highlands. However, many palaeoclimatic
records available from the Loess Plateau, a conjunction region between westerly and monsoon regions, show great
*Corresponding author (email: [email protected])
© Science China Press and Springer-Verlag Berlin Heidelberg 2010
complications of climate system from their achievement
[7–9]. Concerning about the loess-paleosoil achieves, they
always yielded chronology problems due to lack of material
or being unclear about component for radiocarbon dating.
Low sample temporal resolution (centennial-millennial)
caused by deposit/erosion process is another problem.
Therefore the loess-paleosoil record could not set up a reliable chronology for abrupt climate change. Chinese Loess
Plateau is one of the original of Chinese civilization. Many
researches show the culture evolution in Neolithic always
accompanied with environmental change, especially hazards
or abrupt climate changes [10,11]. Therefore, it is very important to reconstruct high-resolution Holocene paleoclimate change in Loess Plateau especially abrupt climate
change. This will help to understanding the climate change
in the margin of the Loess Plateau as well as to giving the
climate background for culture evolution.
The Tianchi Lake (Guanshan Tianchi Lake or Chaonaqiu
Lake), nearly at the top of Liupan Mountain, is located on
the western Loess Plateau (Figure 1), Zhuanglang County,
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ZHOU AiFeng, et al.
Figure 1
Chinese Sci Bull
July (2010) Vol.55 No.20
2119
Location of Tianchi Lake (a), vegetation (b), Abies leaves remains in sediment (c), and partial lamination structure of core (d).
Gansu Province. Field investigation shows that the lake is a
small intermittent discharge dammed lake, with 2430 m
altitude and nearly 200000 square meter catchment area.
Tianchi Lake is 250 m long in north-south and 150 m wide
in west-east, thus covering an area of about 20000 m2. The
lake is approximately up to 8.2 m deep and has comparatively steep slopes by in situ sonar detection. The lake water
is mainly fed by rainfall. The average MAP and MAT at
Tianchi Lake is about 677 mm and 3.4°C based on the data
from two nearest stations(Liupan Mountain station, at 2845
m a.s.l.; Zhuanglang station, at 1615 m a.s.l.). The natural
forest has been mostly destroyed since the 1950s due to
human deforestation. At present, the vegetation on the
mountains surrounding Tianchi Lake is dominated by
shrubs and steppe. The lake is the original of Hulu River,
tributary of Weihe River, no more than 50 km from Dadiwan, a famous Neolithic archaeological site in China.
Two 11-m-long parallel sediment cores were taken at
Tianchi Lake in September 2007 using a Piston Corer with
platform UWITEC at the water depth of 8.2 m. The lithology of the almost whole core is consisted of silty lacustrine
sediments with 1–2 mm thickness distinctive organicdetritus lamination (Figure 1(c)). Many terrestrial leaves
and twigs were found during the subsampling, affording
good terrestrial material for the radiocarbon dating, which
can avoid the reservoir effect occurred in many lake sedi-
ment in the west part of China [12,13]. In January 2008,
another long core was taken by using deep corer, which
drilled through the sediment to bedrock.
Abies leaf macrofossils were picked out and graphite
synthesis was taken in chronology laboratory, Key Laboratory of Western China’s Environmental System, Lanzhou
University. Radiocarbon measured by using accelerator
mass spectrometry (AMS) at the AMS Dating Laboratory at
Peking University (Beijing, China). All dates were calibrated to calendar years before present with the program
OXCAL4.1 [14] using IntCal04 calibration data set [15]. A
6200 Cal a BP age-depth model was established (Figure 2a)
with the same accumulation about 1.85 mm/a, which was
also confirmed by varve counting.
Fossil pollen assemblages, magnetic susceptibility (MS)
and color scale were measured (Figure 2). We take pollen
analysis with 16 cm interval (with ca. 80–90-year resolution)
and 1cm interval in magnetic susceptibility as well as color
scale (with ca. 5–6-year resolution). In general, the records
in Tianchi Lake in the Loess Plateau show the same trend
with cave deposits stable isotope records in monsoon region
[2,3] in climate change. Monsoon declined during the middle Holocene indicated by decrease of deciduous tree. The
vegetation changed from deciduous-conifer mixed forest
dominated by Betula Quercus, Picea and Pinus at 6200–
2900 Cal a BP; through steppe forest co-dominated by tree
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ZHOU AiFeng, et al.
Chinese Sci Bull
July (2010) Vol.55 No.20
Figure 2 The AMS results of core GSA in Tianchi Lake (a) and deciduous pollen percentage (b), magnetic susceptibility (c), redness (d) and cave deposit
oxygen isotope results of Shanbao cave (e), Dongge cave (f).
(Betula, Picea and Pinus) and herb (Artemisia) at 2850–
1150 Cal a BP, to open vegetation dominated by steppe
herbs after 1150 Cal a BP. The overall pattern of vegetation
change shows a drying climate trend over the last 6200
years, which is likely in response to weakening summer
monsoon as documented by other independent climate records. Modern magnetic susceptibility derived from surface
soil in the Tianchi Lake catchment indicated the MS value
was contributed by the aeolian input, which was also proved
in Lake Huguangyan, a Maar Lake in Guangdong Province
[16]. MS at the Tianchi Lake shows a relatively stable state
before 2700 Cal a BP, then increasing gradually. It shows
significant increase after 1100 Cal a BP. The increasing of
MS may influenced by the aeolian input induced by anthropogenic impact or winter monsoon winds. On the contrary, the strong summer monsoon may cause the decreasing
of MS. For example, low values of MS at 1900, 2700, 4400
and 5200 Cal a BP correspond with increased summer
monsoon indicated by Shanbao and Dongge cave deposits
[2,3]. Sediment redness in color scales, which is related to
the material supply of lake sediment, could indicate paleoclimatic changes in the core [17]. The Tianchi Lake sediment mainly supplied by eroded verrucano which was
transported by fluvial means into the lake. Thus, redness
increases at times of increased precipitation, that is, as
monsoon strength increases [18]. Redness recorded 13 times
abrupt fluctuated precipitations at 500, 950, 1250, 1700,
2250, 2600, 3100, 3600, 4100, 4850, 5200, 5850 and 6150
Cal a BP. But in the east monsoon region, cave deposit records did not show so many events. It may be caused by the
complication on the Loess Plateau.
Sediments from the Tianchi Lake afford very good highresolution mid-late Holocene climate change achieve for the
Loess Plateau. The preliminary result shows that the basic
ZHOU AiFeng, et al.
Chinese Sci Bull
climate background was in agreement with the records from
cave records in monsoon region in eastern China. Besides, it
shows more detail record in abrupt climate change. This
high-resolution record provides the background of climate
change for the Neolithic culture evolution in the western
Loess Plateau, such as Dadiwan culture. Further research
will focus on the lamination of Tianchi Lake sediment. Reliable annual chronology will be taken from well-preserved
organic-detritus laminations. Hopefully we could obtain
nice records on ENSO events, flood, winter monsoon researches as well as temperature record during mid-Holocene.
The records would also discover the relation between human revolutions, human activities and climatic, environmental changes in the western Loess Plateau, China.
We would like to thank Zhuanglang Prefectural Forestry Bureau and Han
Dong, head of Taomushan forestry centre, for fieldwork assistance, Cao
Jixiu, Zheng Tongming, Liu Jiao, Lü Yanbin, Xue Qian, Li Zhifei for helping in the field and laboratory assistance. This work was supported by the
National Natural Science Foundation of China (40801074, 40601094,
40971056 and 40761029), NSFC Innovation Team Project (40721061) and
the “111” project #B06026.
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