Quantitative reconstruction of summer precipitation using a mid-Holocene <i>δ</i><sup>13</sup>C common millet record from Guanzhong Basin, northern China
To quantitatively reconstruct Holocene precipitation for particular geographical areas, suitable proxies and faithful dating controls are required. The fossilized seeds of common millet (<i>Panicum miliaceum</i>) are found throughout the sedimentary strata of northern China and are suite...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-12-01
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| Series: | Climate of the Past |
| Online Access: | http://www.clim-past.net/12/2229/2016/cp-12-2229-2016.pdf |
| Summary: | To quantitatively reconstruct Holocene precipitation for
particular geographical areas, suitable proxies and faithful dating controls
are required. The fossilized seeds of common millet (<i>Panicum
miliaceum</i>) are found throughout the sedimentary strata of northern China and
are suited to the production of quantitative Holocene precipitation
reconstructions: their isotopic carbon composition (<i>δ</i><sup>13</sup>C) gives a
measure of the precipitation required during the growing season of summer
(here the interval from mid-June to September) and allows these seeds to be
dated. We therefore used a regression function, as part of a systematic study
of the <i>δ</i><sup>13</sup>C of common millet, to produce a quantitative
reconstruction of mid-Holocene summer precipitation in the Guanzhong Basin
(107°40′–107°49′ E,
33°39′–34°45′ N). Our results showed that mean summer
precipitation at 7.7–3.4 ka BP was 353 mm, ∼ 50 mm or 17 %
higher than present levels, and the variability increased, especially after
5.2 ka BP. Maximum mean summer precipitation peaked at 414 mm during the
period 6.1–5.5 ka BP, ∼ 109 mm (or 36 %) higher than today,
indicating that the East Asian summer monsoon (EASM) peaked at this time.
This work can provide a new proxy for further research into continuous
paleoprecipitation sequences and the variability of summer precipitation,
which will promote the further research into the relation between early human
activity and environmental change. |
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| ISSN: | 1814-9324 1814-9332 |