| Autor: |
Stefan Hussenoeder |
| Rok vydání: |
1998 |
| Předmět: |
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| Zdroj: |
Seismic and magnetic constraints on the structure of upper oceanic crust at fast and slow spreading ridges |
| DOI: |
10.1575/1912/4780 |
| Popis: |
The upper ocean crust contains a comprehensive record of the shallow geological processes active along the world's mid-ocean ridge system. This thesis examines the magnetic and seismic structure of the upper crust at two contrasting ridges-the fast spreading East Pacific Rise (EPR) and the slow spreading Mid-Atlantic Ridge (MAR)-to build a more complete understanding about the roles of volcanic emplacement, tectonic disruption and hydrothermal alteration in the near-ridge environment. A technique that inverts potential field measurements. directly from an uneven observation track is developed and applied to near-bottom magnetic data from the spreading segments north of the Kane transform on the MAR. It is concluded that the central anomaly magnetization high marks the locus of focused volcanic emplacement. A cyclic faulting model is proposed to explain the oscillatory magnetization pattern associated with discrete blocks of crust being transported out of the rift valley between intensely altered fault zones. Seismic waveform and amplitude analyses of the magma sill along the EPR reveal it to be a thin ( |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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