The study of impact of Antarctic ice melting event since Last Glacial Maximum for global environmental change

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We have measured the radiocarbon and hydrogen isotope contents of individual, solvent-extractable, short-chain (C14, C16, and C18) fatty acids isolated from Ross Sea surface sediments. The corresponding 14C ages are equivalent to that of the post-bomb dissolved inorganic carbon (DIC) reservoir. Moreover, molecular 14C variations in surficial (upper 15 cm) sediments indicate that these compounds may prove useful for reconstructing chronologies of Antarctic margin sediments containing uncertain(and potentially variable) quantities of relict organic carbon. A preliminary molecular 14C chronology suggests that the accumulation rate of relict organic matter has not changed during the last 500 14C yr. The focus of this study is to determine the validity of compound-specific 14C and hydrogen isotope analysis as a technique for reconstructing chronologies of Antarctic ice melting events.Furthermore, we studied 3 sediment cores recovered from off Antarctic Peninsula to reconstruct the melting h … More istory of the Antarctic Ice sheet during the last 24 kyrs. Rafted Debris (IRD) and terriginous material from the Antarctic Continent were investigated throughout the cores to obtain the timing and the magnitude of the melting events.- We employed the proxy to understand the origin of the sediments using the relative abundances of K2O and Na2O. -Surface sediments K2O/Na2O ratio correlated with the the degree of the influence from 3 surface currents in the region and hence the ratio can constrain the source area of the sediments. Chronologies of these cores were constructed based on both radiocarbon dating of sedimentary organic carbon and the relative abundance of radiolaria Cycladophora davisiana. Analyzing IRD, K2O/Na2O ratio, 14C and radiolaria in the cores showed temporal variations of IRD flux as well as the source regions of the sediment supply during the LGM to the present. IRD maxima were observed in 25-17 and 15-12 ka that show the considerable expansion of the ice sheet during the, LGM and rapid melting of the ice sheet at the time of the global melt water pulse la event respectively. Less