| Summary: | 碩士 === 國立臺灣海洋大學 === 應用地球科學研究所 === 105 === In this study, I used oxygen isotopes measured from benthic foraminiferal shells of Cibicides wuellerstorfi to establish an oxygen isotope stratigraphy for the past 720,000 years from a Banda Sea core MD012380 (5°45’S, 126°54’E). The benthic δ18O values in this core vary between 4.88 ‰ to 1.12 ‰ with obvious glacial and interglacial changes. For establishing our MD012380 benthic isotope stratigraphy, we tuned the oxygen isotope curve to a global benthic LR04 stack by the MATCH Program. The age tuning is also constrained by the last appearance datum of pink Globigerinoides ruber (~130ka) and the position of Brunhes/Matuyama magnetic reversal observed from the core. Cross-spectral analyses were conducted by using MD012380 benthic δ18O values and LR04 stack to reach near-zero phases at three major orbital frequency bands (100kyr-1, 41kyr-1, and 23kyr-1) that verify the validity of the age model. I also found that the planktic isotopes lag behind benthic at the eccentricity frequency band. I also substracted the planktic isotope values from the benthic, and the residuals δ18Obenthic-planktonic are mainly driven of local surface temperature and salinity changes. The results indicate that surface water in the Banda Sea has been characterized by low temperature and high salinity in glacials and high temperature and low salinity in interglacials. I also tested my data by removing the ice volume effect from the benthic δ18O variations of core MD012380 (δ18Obenthic-ice sheet), which reflect mainly local temperature and salinity effects of deep water. The δ18Obenthic-ice sheet curve and the benthic isotope share a similar pattern, though the amplitude of the δ18Obenthic-ice sheet is relatively smaller than the benthic isotope, indicating that the global ice volume effect on the isotope composition changes of water mass is much stronger than the water mass property changes in the deep water.
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