Thesis (Ph. D.)--University of Oregon, 2004. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 171-180). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (M.S.)--University of Tennessee, Knoxville, 2010. / Title from title page screen (viewed on July 20, 2010). Thesis advisor: Robert D. Hatcher, Jr. Vita. Includes bibliographical references.

Thesis (M.S.) University of Wisconsin--Madison, 1960. / Typescript. Nine folded leaves in pocket. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves ).

Thesis (Ph. D.)--University of Tennessee, Knoxville, 2009. / Title from title page screen (viewed on Mar. 26, 2010). Thesis advisor: Robert D. Hatcher, Jr. Vita. Includes bibliographical references.

A free-air gravity anomaly map of the area between 10°-17°N and 90°-101°W shows distinctive positive and negative anomalies which parallel the Tehuatepec Ridge. The positive anomaly approximately overlies the topographic expression of the ridge. On the wide continental shelf southeast of the Gulf of Tehuantepec a positive gravity anomaly with an amplitude in excess of +100 mgal parallels the coast for most of its length and turns abruptly inland at its northern end. A crustal and subcrustal cross section constrained by gravity, magnetic, seismic reflection and seismic refraction data and oriented normal to the Guatemala continental margin indicates the positive shelf anomaly is primarily the result of a relatively shallow 2.62 g/cm³ density block which may be continuous with and genetically similar to the rocks of the Nicoya Complex on the Nicoya Peninsula, Costa Rica. A crustal and subcrustal cross section normal to the continental margin off southern Mexico northwest of the Tehuantepec Ridge shows a shelf structure which is very different from the continental margin off Guatemala. This suggests different tectonic interactions at the convergent plate boundaries on opposite sides of the ridge. The Tehuantepec Ridge, in a crustal and subcrustal cross section oriented normal to its trend, is shown to occur at the juncture of two oceanic crusts of different structure and age. Southeast of the ridge in the Guatemala Basin the crust is about 9.5 km thick and northwest of the ridge the crust is about 12 km thick. Hence the Tehuantepec Ridge is essentially a fracture zone, but because its orientation is oblique to present plate motions and it is aseismic, it is concluded to be a relic fracture zone. / Graduation date: 1976

Gravity and seismic data obtained by the geophysical group at Oregon State University on the R/V YAQUINA during 1969, 1971, and 1973 plus other available data over the area just west of Nicaragua and Costa Rica indicate the tectonic complexity of the region. Gravity measurements show negative free-air anomalies over the Middle America Trench and the continental shelf of Nicaragua with values as low as -120 mgal and -90 mgal respectively. An outer shell gravity high of +35 mgal occurs between the lows. A large positive anomaly attaining values as high as +110 mgal is associated with the Nicoya Complex, a late Mesozoic assemblage, on the Nicoya Peninsula, Costa Rica. Continuous seismic reflection records acquired along the continental shelf of Nicaragua and Costa Rica indicate a large sediment-filled basin off the coast of Nicaragua coincident with the large negative gravity anomaly on the shelf. Free-air gravity anomalies and seismic reflection profiles suggest an offshore continuation of the Nicoya Complex. Two crustal and subcrustal cross sections of the continental margin of Nicaragua show a large anticlinal structure near the surface of the outer shelf. This structure and an underlying layer are postulated to be marine sediments and basalts similar to those of the Nicoya Complex. The cross sections suggest a ruptured oceanic layer beneath the trench. Imbricate thrusting of oceanic crust along the continental slope is postulated as the mechanism of formation of the continental slope and shelf, and hence the Nicoya Complex of Costa Rica. This model has to be modified for southern Costa Rica where the Cocos Ridge terminates the Middle America Trench. The present elevation of the Nicoya Complex onshore may be attributed to imbricate thrusting and concurrent uplift of the shelf by the Cocos Ridge during subduction. / Graduation date: 1976

Thesis--Massachusetts Institute of Technology. / Vita.

Thesis (M.S.)--Oregon State University, 2003. / Includes maps in pocket. Typescript (photocopy). Includes bibliographical references (leaves 57-63). Also available via the World Wide Web.

Thesis (B.Sc.(Hons))--University of Adelaide, Department of Economic Geology,1960.

Thesis (B.Sc.(Hons.)) --University of Adelaide, 1980.