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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
2013
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| Online Access: | https://doi.org/10.1594/PANGAEA.820875 |
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| _version_ | 1867170963782631424 |
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| author | Kessarkar, Pratima Mohan Rao, V Purnachadra Naqvi, Syed Wajih Ahmad Karapurkar, Supriya G |
| author_facet | Kessarkar, Pratima Mohan Rao, V Purnachadra Naqvi, Syed Wajih Ahmad Karapurkar, Supriya G |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Variations in the Indian summer monsoon (ISM) intensity during the last 16.7 ka have been studied using organic carbon (Corg), d15N of sedimentary organic matter, CaCO3, sediment texture, d18OC, and Mg/Ca-derived sea surface temperature, d18O of sea water and sea surface salinity, in a 14C-dated sediment core from the eastern Arabian Sea. The d18O in water and planktonic foraminifera shells off the central west coast of India may be controlled by the ISM intensity as this area receives high precipitation and land runoff. Also, the Corg and CaCO3 contents of sediments and d15N of sedimentary organic matter may be linked to ISM-induced productivity and denitrification. The results of the present study reveal that between 16 and 15.2 ka BP, the ISM was weak with minor fluctuations and started intensifying around 15.2 ka BP, at the onset of the Bølling-Ållerød (B-A) event. The B-A event is characterized by higher water column denitrification rates comparable to the present day. The ISM signatures observed in the d18OC record of B-A event compare well with those from Timta cave of the western Himalayas and also the Asian summer monsoon signatures from the Hulu caves in China and warming signatures in Greenland Ice Sheet Project 2 (GISP2) suggesting atmospheric teleconnections through Intertropical Convergence Zone. The boundary between the Younger Dryas and the Holocene is discernible with small episodes of abrupt events of increased ISM intensity. This decrease in d18OC values at ~11.8 ka BP is contemporary with June solar insolation maximum at 30° north and the increase in methane in the GISP2 ice core supporting episodes of warmer climate and increase in ISM intensity. The ISM seems to have been most stable between 7 and 5.6 ka BP. The core exhibits periodicity of 500 years that is comparable to the Atlantic water formation and the Chinese monsoon. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_820875 |
| institution | PANGAEA |
| language | en |
| publishDate | 2013 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | (Table 1) Age determination of sediment core AAS-62/2 Kessarkar, Pratima Mohan Rao, V Purnachadra Naqvi, Syed Wajih Ahmad Karapurkar, Supriya G AAS-62/2; Age, 14C AMS; Age, 14C calibrated, CALIB 5.0.2 (Stuiver et al., 2005); Age, dated; Age, dated, standard deviation; Arabian Sea; Calendar age; Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; GC; Gravity corer; Laboratory number Variations in the Indian summer monsoon (ISM) intensity during the last 16.7 ka have been studied using organic carbon (Corg), d15N of sedimentary organic matter, CaCO3, sediment texture, d18OC, and Mg/Ca-derived sea surface temperature, d18O of sea water and sea surface salinity, in a 14C-dated sediment core from the eastern Arabian Sea. The d18O in water and planktonic foraminifera shells off the central west coast of India may be controlled by the ISM intensity as this area receives high precipitation and land runoff. Also, the Corg and CaCO3 contents of sediments and d15N of sedimentary organic matter may be linked to ISM-induced productivity and denitrification. The results of the present study reveal that between 16 and 15.2 ka BP, the ISM was weak with minor fluctuations and started intensifying around 15.2 ka BP, at the onset of the Bølling-Ållerød (B-A) event. The B-A event is characterized by higher water column denitrification rates comparable to the present day. The ISM signatures observed in the d18OC record of B-A event compare well with those from Timta cave of the western Himalayas and also the Asian summer monsoon signatures from the Hulu caves in China and warming signatures in Greenland Ice Sheet Project 2 (GISP2) suggesting atmospheric teleconnections through Intertropical Convergence Zone. The boundary between the Younger Dryas and the Holocene is discernible with small episodes of abrupt events of increased ISM intensity. This decrease in d18OC values at ~11.8 ka BP is contemporary with June solar insolation maximum at 30° north and the increase in methane in the GISP2 ice core supporting episodes of warmer climate and increase in ISM intensity. The ISM seems to have been most stable between 7 and 5.6 ka BP. The core exhibits periodicity of 500 years that is comparable to the Atlantic water formation and the Chinese monsoon. |
| title | (Table 1) Age determination of sediment core AAS-62/2 |
| topic | AAS-62/2; Age, 14C AMS; Age, 14C calibrated, CALIB 5.0.2 (Stuiver et al., 2005); Age, dated; Age, dated, standard deviation; Arabian Sea; Calendar age; Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; GC; Gravity corer; Laboratory number |
| url | https://doi.org/10.1594/PANGAEA.820875 |