Graduation date: 1973

Detailed bathymetric survey data were collected along the Peruvian continental margin and were compiled by the author and other investigators to construct a new bathymetric map for the area between 6° to 18°S latitude. Based on this map and individual bathymetric profiles, the continental shelf topography is essentially flat. Four different physiographic provinces (A-D) are defined on the continental slope. Each province apparently reflects the structural and tectonic settings in a given area. The trench is separated into three provinces on the basis of regional depth differences. Three sedimentary basins, Sechura, Salaverry, and Pisco, are recognized on the Peruvian continental shelf between 6° to 15°S. The landward migration on the axis of deposition within these basins is interpreted to be the sedimentary response to tectonism (uplift) taking place along the outer edge of the continental margin. Prominent sedimentary basins also occur on the upper continental slope; these basins have been named with respect to their geographic position as the Lima and Arequipa Basins. Landward and seaward migration of the axis of maximum deposition in these basins is interpreted to be the result of variable rates of uplift along the outer margin. Uplift along the seaward edge of these basins suggests that the accretion of trench and oceanic plate deposits is taking place along the lower and middle continental slope. Seismic reflection profiles, extrapolation of regional structural trends onshore to offshore along the Peruvian margin, and positive free-air gravity anomalies off southern Peru (Whitsett, 1975), show that an outer continental shelf high is present off northern and central Peru. This high is believed to be composed of Paleozoic rocks with a possible Precambrian core. The high is linked with the Amotape Mountains in northern Peru and the Coastal Ranges in southern Peru. It is an important element in the development of the Peruvian continental margin. Using all of the data available, a four stage model is proposed for the Mesozoic-Cenozoic evolution of the Peruvian continental margin. Stage I describes conditions prior to the formation of the subduction zone during Triassic time. Plate collision is postulated at the beginning of Stage II with the formation of a Benioff Zone about 180 m.y. ago (Triassic-Jurassic boundary). Accretion of trench and oceanic plate deposits occurs as a result of the initiation of under-thrusting of the South America Block by the Nazca Plate. Stage III describes the continuous seaward growth of the continental slope during middle to late Cretaceous time. During late middle (Turonian) and middle late Cretaceous (Santonian) time diastrophism in southern Peru restricted the marine conditions to central and northern Peru. During late Cenozoic time (Stage IV) the Peruvian margin attained its present configuration through continuous seaward growth of the continental slope and buildup of the sedimentary sequences found in the Sechura, Salaverry, and Pisco Basins, in central and northern Peru. Late Cenozoic volcanism in southern Peru is apparently associated with the large amount of sediments that reached the southern Peru Trench since late Cretaceous time. The Nazca Ridge apparently approached the Peruvian continental margin during Cenozoic time, and locally changed the morphology of the continental slope. The proposed model shows that the Peruvian continental margin is growing seaward and that continental erosion of the crystalline continental block is not necessary along the Peruvian continental margin. The model explains and justifies the presence of the outer continental shelf high off northern and central Peru. / Graduation date: 1976

The thesis examines the principal air-sea properties at Ocean Station Vessel N (30N 140W). In a descriptive section, meteorological and oceanographic data for N are analyzed over 20 years (1951-1970) and 7 years (1964-1970), respectively. A rainfall estimate is constructed for the 20 year period. The yearly average rainfall is 22 centimeters, far less than current estimates. Daily and seasonal variations are presented. Heat budgets of the surface show that the two decades are distinctly different. Anomalies of the 20 years of all meteorological variables are calculated. The pressure anomaly appears to be loosely correlated with anomalous large scale events in the equatorial dry zone. Time series cross-sections are shown of the mixed layer depth, bottle temperature and salinity. The near surface density appears to be largely controlled by temperature. Surface wind speed, air pressure, sea temperature, air temperature and dew point spectra for a 10-year period (1961-1970) are shown in a spectral section. Spectra are computed separately for the 4 seasons. Rotary spectra for the wind are also calculated. In a discussion of mixed layer dynamics, theoretical calculations indicate that salinity is not a significant factor in the Eastern subtropics. In a final section, Denman's mixed layer model is applied to two cases of data from N. It is found that Denman's model describes the local mixed layer changes in the one case where advective effects could be resolved. It is suggested that mixed layer extinction lengths for sunlight are shorter than previously believed--about 5 meters. Denman's mixed layer model appears applicable to local changes in the Eastern subtropics. / Graduation date: 1974

Graduation date: 1984

Thesis (M.S.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 99-106). / xi, 106 leaves, bound ill. (some col.), col. maps 29 cm

A description is presented of some of the oceanographic features of the northern Chilean waters as indicated by a study of the distribution of properties and of direct current measurements during the Marchile II Expedition, 1962. A narrow band of cold, low salinity water of low oxygen content close to the coast; an oxygen minimum layer from 50 to 400 m and the permanence of the Peru - Chile undercurrent are the outstanding features of the area. The process of upwelling is suggested as the main cause of the distribution of properties near the coast. However this process of upwelling was probably in a quiescent state during the Marchile II Expedition, being much less intense than during other expeditions in the same area, and than in other similar upwelling regions of the world. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Several series of measurements of the hydrography, currents, and winds during the past ten years are used as a basis for an overview of the physical oceanography and meteorology during the upwelling season near Newport, Oregon. Data are described using elementary statistics, progressive vector diagrams, coordinate system independent spectra, and complex demodulation. The resulting description strengthens and extends the conceptual model of coastal upwelling. Averages of various series of data are calculated with the aim of making the collected information more readily available and giving perspective to specific data. The time series analysis indicates which bands of frequencies contain important portions of the coherent energy. Complex demodulation is used to show how the energy in selected frequency bands is distributed as a function of time. It is concluded that the long-term seasonal average of the winds and the hydrography behaves smoothly, but the short-term fluctuations around the average are important. The relationships between the short-term variations in the current and hydrography are as yet unclear, but directions are indicated for further analysis and experimentation. / Graduation date: 1972

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND LINDGREN / Bibliography: leaves 269-280. / by Marjorie Styrt Goldfarb. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1979. / Microfiche copy available in Archives and Science. / Bibliography: leaves 68-71. / by Sarah S. Huested. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1980. / Microfiche copy available in Archives and Science. / Bibliography: leaves 79-80. / by Andrew G. Hudson. / M.S.