Magnetic and gravity interpretation of Yaloc-69 data from the Cocos plate area Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/c247dw58r

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • 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.
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome) using ScandAll PRO 1.8.1 on a Fi-6670 in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces
Additional Information
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2012-05-08T16:15:45Z (GMT) No. of bitstreams: 1 LuRichardShih-Ming1971.pdf: 886464 bytes, checksum: c0cd7b75d5789136317fccf66cd8e672 (MD5)
  • description.provenance : Submitted by Sergio Trujillo (jstscanner@gmail.com) on 2012-04-24T00:15:05Z No. of bitstreams: 1 LuRichardShih-Ming1971.pdf: 886464 bytes, checksum: c0cd7b75d5789136317fccf66cd8e672 (MD5)
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2012-05-07T17:10:19Z (GMT) No. of bitstreams: 1 LuRichardShih-Ming1971.pdf: 886464 bytes, checksum: c0cd7b75d5789136317fccf66cd8e672 (MD5)
  • description.provenance : Made available in DSpace on 2012-05-08T16:15:45Z (GMT). No. of bitstreams: 1 LuRichardShih-Ming1971.pdf: 886464 bytes, checksum: c0cd7b75d5789136317fccf66cd8e672 (MD5) Previous issue date: 1971-04-21

Relationships

Parents:

This work has no parents.

Last modified

Downloadable Content

Download PDF

Items