Stalagmite Inferred High Resolution Climatic Changes through Pleistocene-Holocene Transition in Northwest Indian Himalaya

Abstract

Investigated for d 18 O and d 13 C isotopes, mineralogy and growth rate, a 20 cm long and 230Th-dated calcite stalagmite from Kalakot (Jammu and Kashmir Himalaya), has recorded high resolution precipitation variability during the Pleistocene-Holocene transition. At present, the study area is influenced by both the Indian Summer Monsoon (ISM) and Westerlies. The StalAge model indicates that the stalagmite grew between 16.3 ka to 9.5 ka BP under the ideal isotopic equilibrium conditions as revealed by the Hendy test results. The d18 O and d 13 C values range from -5.41 to -8.82% and -7.09 to -10.84% respectively. Although the U/Th chronology is poor due to low Uranium content in the samples resulting in relatively large errors, the first stalagmite inferred precipitation variability reconstructed from NW Indian Himalaya makes this study significant. The near footprints of three global events, e.g., Older Dryas (OD), Allerød period and Younger Drays (YD) can be noticed at ~14.3-13.9, 13.9-12.7 and 12.7-12.2 ka BP. The precipitation strength was weaker during the OD and YD, but was stronger during the Allerød interstadial. By the termination of YD interval, the climate seems fluctuating in the NW Himalaya. There seems variation in commencement, duration and termination of the above mentioned events in different parts of the globe due to latitude location and response time.

The Indian Summer Monsoon from a Speleothem d¹⁸O Perspective – a Review

“…Nearly all stadials in the 240 ka Bittoo cave record [13] are characterised by more positive δ 18 O values compared to interstadials, consistent with the modeling results given by Pausata et al [102]. Unlike the LIA, this pattern of more positive δ 18 O is replicated by other shorter records from north and northeast India [15][16][17]44] (Figure 3). The Bittoo and Mawmluh cave records suggest that Heinrich stadials are responsible for higher amplitude changes in the ISM than the YD stadial in north and northeast India ( Figure 5).…”

“…Records from peninsular Valmiki cave covers the later phase of Heinrich event 1 [50] and the last deglaciation [49]. Bittoo [13], Kalakot [44] and Timta [15] caves from north India and Mawmluh [16,17,46] cave from northeast India cover the Bølling-Allerød (BA) and Younger Dryas (YD) periods. Sahiya [10,12] cave from north India, Mawmluh [45] and Umsynrang [61] caves from northeast India and Kotumsar [57] cave from peninsular India encompass significant periods of the Holocene.…”

“…Examination of such events requires tight age control and high confidence in the climatic influence on the δ 18 O record. The Bittoo [13], Kalakot [44], Timta [15] and Mawmluh [16,17] cave records provide measurements of δ 18 O covering the BA and YD periods. The Bittoo and Timta cave stalagmites from north India provide better age control ( Figure 5) than the Kalakot record.…”

“…However, the transition into and out of the Heinrich stadials is not as distinct as the transition into the YD. The transition to the YD occurs abruptly (within ~100 years) at 12.7 ka in the north Indian Bittoo [13], Timta [15] and Kalakot [44] records ( Figure 5 Younger Dryas (YD) and Heinrich events 1 and 2 [103] are indicated by yellow bars. Bölling-Allerød (BA), is indicated by a grey bar.…”

“…The BA-YD transition is marked at 12.8 ka BP in the figure (GISP2 [104]). Bittoo [13], Kalakot [44], Timta [15] and Mawmluh [16,17] records are shown along with their U-Th age errors.…”