Origin and evolution of selected plate boundaries. Part I: Tectonic and thermal history of Australia's southern margin. Part II: Development of the Caroline plate region (passive) [microform]
- Bib ID:
- 3287564
- Format:
- Book and Microform
- Author:
- Hegarty, Kerry Anne
- Description:
- 265 p.
- Summary:
-
The origin and evolution of convergent and divergent plate boundaries are investigated at two marine locations where the earliest stages of boundary development can be examined. At divergent plate boundaries, subsidence histories calculated from structural, thermal and/or stratigraphic data place important constraints on models of the sub-crustal processes that control margin formation. Studies of stratigraphic and seismic reflection data from Australia's southern margin indicate that there is a distinct two-part subsidence history of the margin that can be modelled as lithospheric stretching (rapid subsidence) followed by thermal cooling and contraction (slow subsidence). The temperature history predicted from the same lithospheric stretching model is consistent with that inferred from the analysis of fission track lengths within the margin's sediments.
Furthermore, subsidence analyses and marine magnetic data independently detect a probable west-to-east propagation of the initial emplacement of oceanic crust along the southern margin. The origin and evolution of a convergent plate boundary is investigated at the easternmost portion of the Caroline plate where it abuts the Pacific plate. The Caroline-Pacific plate boundary consists in part of the Mussau Trench and the Sorol Trough. Gravity modelling and regional plate relationships suggests that convergence at the Caroline-Pacific plate boundary may be as young as only a few million years. A new model for the complex tectonic evolution of the Caroline plate suggests that it formed by Oligocene back-arc spreading behind a once-active arc that is now located in New Guinea. Back-arc spreading was associated with northward-dipping subduction and convergence between the Indo-Australian and Pacific plates.
Presently however, southward-dipping subduction is occurring along northern New Guinea at the New Guinea Trench, implying, a "flip" in subduction polarity that probably occurred within the past 10 m.a.
- Notes:
-
- (UnM)AAI8523173
- Source: Dissertation Abstracts International, Volume: 46-08, Section: B, page: 2601.
- Thesis (Ph.D.)--Columbia University, 1985.
- Reproduction:
- Microfiche. Ann Arbor, Mich.: University Microfilms International.
- Subject:
- Geophysics
- Other authors/contributors:
- Columbia University
- Copyright:
-
In Copyright
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Copyright status was determined using the following information:
- Material type:
- Literary Dramatic Musical
- Published status:
- Unpublished
- Creation date:
- 1985
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