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theses

I present high-resolution (10-15 kyr) δ18O and δ13C from the Kerguelen Plateau Ocean Drilling Program (ODP) Sites 751 and 747 from 15 – 20 Ma. The fidelity of initial age models developed using magneto-biostratigraphy are tested using the stability of the Earth’s 405 kyr eccentricity cycle. The revised age model for Site 751 is astronomically tuned to the 405 kyr eccentricity cycle and the paleomagnetic data are re-interpreted with the aid of the δ18O time series (Mi events) and Wade and Palike’s (2004) nomenclature for eccentricity minima. Astronomical tuning to higher frequencies (obliquity) was not performed in this work due to sample resolution (~10kyr). A comparison of spectral estimates of the untuned record with the tuned counterpart, as well as coherency with Laskar et al. (2004)’s eccentricity solution, indicate that the tuning procedure improved the age model without drastically changing spectral estimates with the addition of tie points. The δ18O and δ13C show strong amplitudes for the long and short (405 and 125 kyr, respectively) eccentricity cycles; however, there is only a weak signal associated with the 40 kyr obliquity cycle which may be attributed to the low temporal resolution at Site 751. Time-frequency analysis shows a decrease in the spectral density of the short eccentricity cycle and an apparent increase in the higher frequency power (possibly the 40 kyr obliquity cycle) around 17 Ma. However, I cannot resolve at this time whether this is an artifact related to a strong dissolution pulse around 17 Ma or if represents a change in the dominant climatic forcing. Overall, Site 751 shows promise for future studies concerning orbitally-paced climate during a period of time when many other deep-sea records are severely affected by dissolution.

ETD_5113

M.S.

Includes bibliographical references

Includes vita

by Ronidell Baluyot

doi:10.7282/T3BV7DNZ

ETD graduate

The author owns the copyright to this work.