East Asian monsoon changes early in the last deglaciation and insights into the interpretation of oxygen isotope changes in the Chinese stalagmite record
Introduction
The last deglaciation (21–11 ka) was punctuated by many climate perturbations (Clark et al., 2012; Ng et al., 2018). Changes in the ice sheets and sea level (Denton et al., 2010; Lambeck et al., 2014), ocean circulation (McManus et al., 2004; Ng et al., 2018), the atmospheric-oceanic carbon cycle (Marcott et al., 2014; Bauska et al., 2016) and low-latitude hydroclimate (Wang et al., 2001; Weijers et al., 2007; Deplazes et al., 2013) are closely associated with millennial-scale events (e.g. Heinrich Stadial 1 (HS1) and Bølling-Allerød (BA)). HS1, one of the most prominent Heinrich stadials of the last ice age, features massive freshwater and iceberg discharge from the Northern Hemisphere ice sheets into the North Atlantic (Heinrich, 1988). Following HS1, the BA period is characterized by warm temperatures in the Northern Hemisphere (Marcott et al., 2014; WAIS Divide Project Members, 2015).
Whereas there have been considerable efforts on providing perspective on the orbital- and millennial-scale climate changes during the last deglacial period (Denton et al., 2010), higher resolution paleoclimate records extend investigations to the centennial-scale and can potentially provide a more precise understanding of processes during the deglaciation sequence (Marcott et al., 2014; Chen et al., 2015; Bauska et al., 2016). For example, three abrupt centennial-scale increases in atmospheric CO2 (each of 10–15 ppmv) superimposed on the millennial-scale changes in the last deglaciation, and have been closely linked to CH4 changes and Northern Hemisphere climate (Marcott et al., 2014). Two of these increases at around 14.8 ka and 11.7 ka were synchronous with the rapid intensification of the Asian monsoon and the abrupt recovery of the Atlantic Meridional Overturning Circulation (AMOC) (Chen et al., 2015). Heinrich events are believed to be associated with strong perturbations on the AMOC and global climate; however, with high-resolution records emerging, HS1 is found not to be one monotonous event and exhibit a two-phase structure (Bard et al., 2000; Broecker et al., 2009; Broecker and Putman., 2012; Huang et al., 2019), along with many other high frequency features (Brendryen et al., 2020). Chinese cave records have also documented a generally weak Asian Monsoon during HS1 (e.g. Wang et al., 2001), but some of the detailed characteristics and forcing mechanisms within this event are still not well understood. With our new record and the previously published Hulu record (Wang et al., 2001; Wu et al., 2009), we now have an opportunity to assess ideas with regard to submillennial-scale changes during the last deglaciation.
Studies about the interpretation of δ18O in Asian caves have often stated that this is a controversial topic (e.g. Chiang et al., 2020). A clear reading of the literature shows that this is not now and has not historically been the case. Indeed, the literature shows that the essence of the interpretations put forth in the original papers on the subject (Wang et al., 2001; Yuan et al., 2004; Johnson and Ingram, 2004; Cheng et al., 2009) have been verified by subsequent empirical and theoretical studies (Liu et al., 2014; Orland et al., 2015; Cheng et al., 2012, 2016). This is not to say that there were not significant unknowns at the time of the early publications. A number of those unknowns have since been elucidated and others still remain. The literature, thus shows that the original publications, laid a solid foundation upon which subsequent publications built, with more work yet to come, in this ongoing, vibrant area of research. Here we use our new data along with published data to test some of the ideas regarding the interpretation of oxygen isotopes in Chinese caves. We then present our conclusions and assessment of the current state of this field.
Here we report a new 230Th/U-dated, high-resolution stalagmite δ18O record spanning much of the early portion of the last deglaciation, from Shima Cave, Hunan Province, central China. This record covers about 4900 years, with an average oxygen isotope resolution of better than 7 years. The stalagmite grew continuously for 1900 years at the end of the last glacial maximum (LGM, 19.7--17.8 ka), then after a 1500-year hiatus, for another 3000 years, covering the last half of HS1, on into the BA (16.3–13.3 ka). We analyze this record in the context of other Asian cave records and other correlative records from around the world. Within this context, we examine the suite of records with the notion that HS1 is characterized by two stages as well as high-frequency features. In addition, we use our record and the now large number of published cave records across Asia to test ideas about the interpretation of the δ18O of Chinese cave deposits. Since these records span a large geographic range, we can now use them to test models that hindcast shifts in δ18O as a function of location.
Section snippets
Materials and methods
Stalagmite sample SM7 was collected from Shima Cave (Fig. 1, 29°35′N, 109°31′E), in Hunan Province of central China, ∼930 km southwest of Hulu Cave (32°30′N, 119°10′E). The cave is at an elevation of ∼650 m and is developed in Permian limestone, with a narrow entrance facing to the southwest. The cave site is strongly influenced by the East Asian Monsoon climate. Modern observational data from the nearest Enshi station (∼80 km north of Shima Cave) shows that the mean annual temperature in this
Chronology
The U and Th isotopic compositions are presented in Table 1. Measured 238U concentrations are low, ranging from 131.4 to 281.3 ppb. However, most of the samples have 232Th concentrations less than 1000 ppt and relatively high 230Th/232Th activity ratios so that corrections for initial 230Th are small. The length of time represented by the hiatus was determined to be ∼1.5 ka, based upon extrapolation to 464 mm of the bounding ages drilled at 460 mm and 470 mm. Three dates at the lower part of
Controlling factors of Chinese stalagmite δ18O
The publication of the original Hulu Cave record (Wang et al., 2001) stimulated a long, fruitful, and ongoing debate on the interpretation of δ18O values recorded in South and East Asian caves. With our new record and the now many records from across Asia, we have an opportunity to assess these ideas with regard to millennial-scale changes. Two mechanisms were proposed in the early studies, the Wang-Cheng Mechanism (Wang et al., 2001; Cheng et al., 2009) and the Yuan Mechanism (Yuan et al., 2004
Conclusions
A new 230Th/U dated, ∼7-year-resolution stalagmite δ18O record from Shima Cave, Hunan Province, provides us with new evidence into the interpretation of speleothem δ18O and the millennial-to sub-decadal-scale monsoon variations during the early portion of the last deglaciation. Our sample SM7 grew in time periods from 19.7 to 13.3 ka, with a ∼1500-year hiatus (from 17.8 to 16.3 ka). The record resembles other Chinese cave records and features the abrupt shift to the highest δ18O values in the
Author statement
Yijia Liang: Conceptualization, Formal analysis, Funding acquisition, Investigation, Writing - original draft. Kan Zhao: Writing- Reviewing and Editing, Project administration, Funding acquisition. R. Lawrence Edwards: Conceptualization, Funding acquisition, Writing- Reviewing and Editing. Yongjin Wang: Writing- Reviewing and Editing, Funding acquisition. Qingfeng Shao: Formal analysis, Investigation. Zhenqiu Zhang: Investigation, Resources. Bin Zhao: Investigation, Resources. Quan Wang: Formal
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgement
We thank Editor Dr. Miryam Bar-Matthews and two anonymous reviewers for their constructive comments. This work was supported by National Natural Science Foundation of China (Grants 42071105, 41931178, 41572151, 41571102, 41672164), the U.S. National Science Foundation (Grant 1702816), the Postgraduate Research & Practice Innovation Program of Jiangsu Province (Grant KYCX19_0789), the 111 Program of China (Grant D19002), the Science and Technology Research Program of Chongqing Municipal
References (86)
- et al.
A Great Basin-wide dry episode during the first half of the Mystery Interval?
Quat. Sci. Rev.
(2009) - et al.
How did the hydrologic cycle respond to the two-phase mystery interval?
Quat. Sci. Rev.
(2012) - et al.
The variation of summer monsoon precipitation in central China since the last deglaciation
Earth Planet Sci. Lett.
(2010) - et al.
Improvements in 230Th dating, 230Th and 234U half-life values, and U-Th isotopic measurements by multicollector inductively coupled plasma mass spectrometry
Earth Planet Sci. Lett.
(2013) - et al.
Role of seasonal transitions and westerly jets in East Asian paleoclimate
Quat. Sci. Rev.
(2015) - et al.
Lessons learned from oxygen isotopes in modern precipitation applied to interpretation of speleothem records of paleoclimate from eastern Asia
Earth Planet Sci. Lett.
(2010) - et al.
Decoupling of monsoon activity across the northern and southern Indo-Pacific during the Late Glacial
Quat. Sci. Rev.
(2017) - et al.
The role of seasonality in abrupt climate change
Quat. Sci. Rev.
(2005) - et al.
Evidence from the Northeastern Atlantic basin for variability in the rate of the meridional overturning circulation through the last deglaciation
Earth Planet Sci. Lett.
(2005) - et al.
The deglaciation over Laurentian Fan: history of diatoms, IRD, ice and fresh water
Quat. Sci. Rev.
(2015)
Origin and consequences of cyclic ice rafting in the Northeast Atlantic Ocean during the past 130,000 years
Quat. Res.
The isotopic geochemistry of speleothems-I. The calculation of the effects of different modes of formation on the isotopic composition of speleothems and their applicability as palaeoclimatic indicators Geochim
Cosmochim. Acta
MOD-AGE: an age-depth model construction algorithm
Quat. Geochronol.
Quantification of Holocene Asian monsoon rainfall from spatially separated cave records
Earth Planet Sci. Lett.
Two-phase structure of tropical hydroclimate during Heinrich Stadial 1 and its global implications
Quat. Sci. Rev.
Decoupling of the East Asian summer monsoon and Indian summer monsoon between 20 and 17 ka
Quat. Res.
Spatial and temporal variability in the stable isotope systematics of modern precipitation in China: implications for paleoclimate reconstructions
Earth Planet Sci. Lett.
Chinese cave records and the East Asia summer monsoon
Quat. Sci. Rev.
Millennial-scale oscillations of the westerly jet path during the last glacial period
J. Asian Earth Sci.
A novel application of triple oxygen isotope ratios of speleothems
Geochim. Cosmochim. Acta
A high-resolution, absolute-dated deglacial speleothem record of Indian Ocean climate from Socotra Island, Yemen
Earth Planet Sci. Lett.
Interactive programs of MC-ICPMS data processing for 230Th/U geochronology
Quat. Geochronol.
High-precision and high-resolution carbonate 230Th dating by MC-ICP-MS with SEM protocols
Geochem. Cosmochim. Acta
Millennial-scale fluctuations of the European Ice Sheet at the end of the last glacial, and their potential impact on global climate
Quat. Sci. Rev.
High resolution secondary ionisation mass spectrometry (SIMS) δ18O analyses of Hulu Cave speleothem at the time of Heinrich Event 1
Chem. Geol.
Speleothem calcite farmed in situ: modern calibration of δ18O and δ13C paleoclimate proxies in a continuously-monitored natural cave system
Geochem. Cosmochim. Acta
Distinct climate change synchronous with Heinrich event one, recorded by stable oxygen and carbon isotopic compositions in stalagmites from China
Quat. Res.
Hydrological impact of Heinrich events in the subtropical northeast Atlantic
Science
Carbon isotopes characterize rapid changes in atmospheric carbon dioxide during the last deglaciation
Proc. Natl. Acad. Sci. Unit. States Am.
A 550,000-year record of East Asian monsoon rainfall from 10Be in loess
Science
Strong and deep Atlantic meridional overturning circulation during the last glacial cycle
Nature
Eurasian Ice Sheet collapse was a major source of Meltwater Pulse 1A 14,600 years ago
Nat. Geosci.
Variability of stalagmite-inferred Indian monsoon precipitation over the past 252,000 y
Proc. Natl. Acad. Sci. Unit. States Am.
Synchronous centennial abrupt events in the ocean and atmosphere during the last deglaciation
Science
Ice age terminations
Science
The Global paleomonsoon as seen through speleothem records from Asia and the Americas
Clim. Dynam.
The Asian monsoon over the past 640,000 years and ice age terminations
Nature
Extratropical cooling, interhemispheric thermal gradients, and tropical climate change
Annu. Rev. Earth Planet Sci.
Enriched East Asian oxygen isotope of precipitation indicates reduced summer seasonality in regional climate and westerlies
Proc. Natl. Acad. Sci. Unit. States Am.
Global climate evolution during the last deglaciation
Proc. Natl. Acad. Sci. Unit. States Am.
Characteristics of the Heinrich 1 abrupt climate event inferred from a speleothem record from Xianyun Cave, Fujian Province
Sci. Bull.
The last glacial termination
Science
Links between tropical rainfall and North Atlantic climate during the last glacial period
Nat. Geosci.
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