Here we present, to date, the highest‐resolved (~5 years) and most precisely dated Holocene monsoon climate reconstruction for the western Chinese Loess Plateau based on five replicated stalagmite δ18O records from Wuya Cave, eastern Gansu, China. Our record suggests the wettest period occurred between 10,500 and 6,600 a BP in this region. After this period, the amplitude of Asian summer monsoon decadal‐scale variability progressively increased likely in response to increasing ENSO frequency since the middle Holocene. Our study reveals similar asymmetric centennial‐scale double‐plunging structures of the 8.2, 5.5, and 2.8 ka events in the western Chinese Loess Plateau, suggesting a possible role of solar activity whose impact was amplified around 8.2 ka BP by the meltwater flood. In contrast, the 4.2 ka event exhibit gradually declining monsoon rainfall with centennial‐ to decadal‐scale fluctuations.
- Award ID(s):
- 1702816
- NSF-PAR ID:
- 10292187
- Date Published:
- Journal Name:
- The Holocene
- ISSN:
- 0959-6836
- Page Range / eLocation ID:
- 095968362110332
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract The 8.2 ka event is the most significant global climate anomaly of the Holocene epoch, but a lack of records from Mainland Southeast Asia (MSEA) currently limits our understanding of the spatial and temporal extent of the climate response. A newly developed speleothem record from Tham Doun Mai Cave, Northern Laos provides the first high‐resolution record of this event in MSEA. Our multiproxy record (δ18O, δ13C, Mg/Ca, Sr/Ca, and petrographic data), anchored in time by 9 U‐Th ages, reveals a significant reduction in local rainfall amount and weakening of the monsoon at the event onset at ∼8.29 ± 0.03 ka BP. This response lasts for a minimum of ∼170 years, similar to event length estimates from other speleothem δ18O monsoon records. Interestingly, however, our δ13C and Mg/Ca data, proxies for local hydrology, show that abrupt changes to local rainfall amounts began decades earlier (∼70 years) than registered in the δ18O. Moreover, the δ13C and Mg/Ca also show that reductions in rainfall continued for at least ∼200 years longer than the weakening of the monsoon inferred from the δ18O. Our interpretations suggest that drier conditions brought on by the 8.2 ka event in MSEA were felt beyond the temporal boundaries defined by δ18O‐inferred monsoon intensity, and an initial wet period (or precursor event) may have preceded the local drying. Most existing Asian Monsoon proxy records of the 8.2 ka event may lack the resolution and/or multiproxy information necessary to establish local and regional hydrological sensitivity to abrupt climate change.
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1177/09596836211033218
