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No description available.

No description available.

Graduation date: 1968

In this thesis, the interpretation and reduction of ocean heat flow measurements are discussed on the basis of theoretical models. The instrument effect x heat flow measurements is investigated for the case of long period measurements by studying the heat conduction along the measurement probe for both steady and unsteady state bottom temperatures. This effect is found to be unimportant. Measurement errors due to recent bottom temperature transients are studied and the possible magnitude of such errors is estimated. Moreover, effects of climatic variation on the ocean floor temperature are estimated on the basis of diffusion models. It is shown that climatic variations with periods longer than one thousand years will be unattenuated and will affect the entire ocean floor. The perturbation method is used to study the effects of an irregular topography and a variable thickness of ocean floor sediments on the heat flow. Some special examples are given to provide a comparison between the perturbation solutions and exact solutions of similar problems. The perturbation method is also applied to a buried body with different thermal conductivity from its surroundings and the reliability of the perturbation solution is examined. Heat flow anomalies due to heat transport by magma intruded into crustal layers is studied by solving the heat conduction equation. It is shown that magmatic intrusions can lead to very large surface heat flow anomalies. Finally, the possibility of deriving the ocean floor thermal gradient on the basis of on-ship measurements performed on sediment cores is investigated. The results appear positive. The temperature variations in flowing wells and the temperature variation in a cylindrical sediment core influenced by the movement of water along the axis of the core are also studied. / Graduation date: 1968

Magnetic, gravity and bathymetry data were collected on an extended cruise of the R/V Yaquina in 1969. The last set of data was obtained from those track lines leaving the Panama Basin. The area covered is mainly the Cocos plate (Molnar and Sykes, 1969). The data is analyzed and compared with results of previous workers and the geophysical implications considered. Generally speaking, from the magnetic part of the data, both direct and indirect methods show support of Vine and Matthew's (1963) hypothesis of sea-floor spreading and the subsequent principles of new global tectonics. The most northern magnetic anomaly profile across the East Pacific rise (at 18.3°N) shows a spreading rate about 3 cm/yr. and the most southern one (at 12.8°N) shows a rate about 5.2 cm/yr. The Cocos plate has been assumed to move in a northeast-southwest direction (N30°E to N45°E), and rotate with respect to the Pacific plate about a pole at 40°N, 110°W with an angular velocity of 19.6x10⁻⁷ deg./yr. (Larson and Chase, 1970). New material comes up from the west boundary - the East Pacific rise, and the south boundary - the Galapogos rift, causing the Cocos plate to underthrust the Americans plate at the middle American arc. Some of the points of new global tectonics can not be detected from this set of data; further detailed study of more track lines and sea bottom core samples are needed. The results of both analytical methods for determining the magnitude of induced and remanent magnetization in the second layer shows some consistence with the work of Schaeffer and Schwarz (1970), and Irving et al. (1970) at the Mid-Atlantic ridge near 45°N, in which a thinner magnetization layer at the ridge and the attenuation of magnetization intensity away from the ridge axis are suggested. Free-air gravity anomaly profiles have been employed to determine the crustal structure of two sections1 a ridge section at 12.8°N and a trench section at 14°N. For the ridge section, if the anomalous mantle was converted from normal mantle, the extension of anomalous mantle into the normal mantle requires some uplift and/or lateral expansion in the rise crest area. The tensional configuration suggested in the trench crustal section agrees with the model proposed by Elsasser (1968) for the differential movement between two lithospheric blocks. This work gives some speculations that evidence which supports the present new global tectonics theory is limited to a certain degree of accuracy. Further study of the theory based upon physics, its mechanism, and measurement techniques that would give more reliable evidence have to be developed before it can be ascertained what really happens beneath this wild, wild world. / Graduation date: 1971

Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1983. / Includes bibliographical notes.

Thesis--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution. / "WHOI-73-58." "Prepared for the Office of Naval Research under contract N00014-66-CO241 ; NR 083-004." Vita. Includes bibliographical references (leaves 201-210).

Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1983. / Grant provided by NASA under Grant NAG 6-9. Includes bibliographical references (p. 187-193).

Thesis (Ph. D.)--University of Hong Kong, 1967. / 8 fold. charts in pocket. Mimeographed.