<p> Millennial-scale variability in the Indian monsoon was temporally linked to changes in global ocean circulation during the last glacial period, as evidenced by planktic-benthic foraminiferal stable isotope and trace element results from an intermediate depth sediment core from the northwestern Bay of Bengal (Core NGHP-01-19B; 18°58'N, 85°39'E; 1,422 m). Paired planktic foraminiferal Mg/Ca and δ<sup>18</sup>O<sub>c</sub> of <i> G. ruber</i> constrain sea surface temperatures and isolate millennial-scale variations in the δ<sup>18</sup>O of surface waters (δ<sup> 18</sup>O<sub>sw</sub>) which resulted from changes in river runoff in the northwestern Bay. Concurrently with low δ<sup>18</sup>O<sub>sw</sub> events, benthic foraminiferal δ<sup>13</sup>C of <i>Cibicidoides </i> spp. decreased, suggesting an increased influence of an aged water mass at this intermediate depth site during the low salinity events. Benthic foraminiferal Cd/Ca of <i>H. elegans</i> supports the identification of this water mass as aged Glacial Antarctic Intermediate Water (GAAIW). Lagged correlation analysis (r= 0.41) indicates that changes in subsurface properties led changes in surface properties by an average of 380 years. The implication is that Southern Hemisphere climate exerted a controlling influence on the Indian monsoon during the last glacial period.</p>
| Identifer | oai:union.ndltd.org:PROQUEST/oai:pqdtoai.proquest.com:1591709 |
| Date | 23 July 2015 |
| Creators | DeLong, Kimberly |
| Publisher | University of New Hampshire |
| Source Sets | ProQuest.com |
| Language | English |
| Detected Language | English |
| Type | thesis |
Page generated in 0.0017 seconds