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Magmatism and rifting at the South Atlantic margin: Magma transport and emplacement mechanisms of mafic dykes from magnetic studies

Wiegand, Miriam

Abstract:

The Henties Bay Outjo Dyke swarm (HOD) in NW Namibia is part of the early Cretaceous Paraná-Etendeka Large Igneous Province, which originated during the early Cretaceous breakup of western Gondwana into Africa and South America. The basaltic dykes consist dominantly of dolerites, which are compositionally equivalent to the erupted lava series and thus the HOD provides a look at the feeder systems of a flood basalt province. The dyke orientations are subvertical and most have NE-SW and minor NW-SE oriented strike directions parallel or perpendicular to the Neoproterozoic Damara Belt in which they intruded.
A petrofabric study is presented for 41 HOD dykes using the anisotropy of low-field magnetic susceptibility (AMS) with the aim to derive magma flow directions and thus better constrain emplacement mechanisms within the dyke swarm. Additionally, the anisotropy of the anhysteretic remanent magnetization (AARM) is applied to a subset of theses samples in order to detect disturbances by grain size effects on the magnetic fabric due to single-domain titanomagnetite. For individual samples also the shape-preferred orientation of plagioclase was determined for comparison with the magnetic fabric. ... mehr


Volltext §
DOI: 10.5445/IR/1000068870
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Geowissenschaften (AGW)
KIT-Zentrum Klima und Umwelt (ZKU)
Publikationstyp Hochschulschrift
Publikationsjahr 2016
Sprache Englisch
Identifikator urn:nbn:de:swb:90-688706
KITopen-ID: 1000068870
Verlag Karlsruher Institut für Technologie (KIT)
Umfang XI, 134 S.
Art der Arbeit Dissertation
Fakultät Fakultät für Bauingenieur-, Geo- und Umweltwissenschaften (BGU)
Institut Institut für Angewandte Geowissenschaften (AGW)
Prüfungsdatum 22.12.2016
Schlagwörter dykes, anisotropy of magnetic susceptibility, magma flow
Referent/Betreuer Greiling, R.
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