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| Titel |
Geometrical constraints of rift fissures on the formation of isolated micro continental blocks during transition from continental rifting to oceanic spreading based on analogue modelling |
| VerfasserIn |
Anna Makushkina, Evgeny Dubinin, Andrey Grokholsky |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250086689
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| Publikation (Nr.) |
 EGU/EGU2014-600.pdf |
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| Zusammenfassung |
| From global ocean bathymetric data, we can observe many intraplate features such us
submerged and non-submerged plateaus below sea level, islands, ridges, banks etc. All these
features can be divided in three main groups: (1) blocks with oceanic crust; (2) blocks with
continental crust; (3) complex features. There are many hypotheses that try to describe their
origin. Hypotheses, which we carried on: (1) features with continental crust formed by ridge
jumping into a continental margin; (2) features with igneous composition formed by
eruption of huge volumes of volcanic rocks; (3) complex features with jigsaw crust
composition.
We present preliminary results of our experimental modeling that show geometrical
constraints for the formation of isolated blocks in oceanic crust due to the evolution of
overlapping spreading centers. These can lead to the formation of an isolated continental
block if all following conditions are met: (1) the angle between extension direction and
pre-existing fractures are between 45° to 60°; (2) the length of two pre-existing
fractures located on opposite sides of model plate is equal; (3) the offset between two
pre-existing fractures located on opposite sides of model plate vary from 1.5 cm to 3 cm.
Extension rates in the model vary from V = 1.67 *10-5 m/sec to V = 2.15x10-5
m/sec which correlate with slow spreading rates. The model plate size was 12x25
cm.
These experiments provide us with a probable mechanism of isolated continental block
formation. In addition, the experiments allow us to distinguish major geometrical
parameters of continental break up modelling. These results are preliminary and
we will study other experimental settings such us influence of hotspot activity,
interaction between propagating ridge and weakened zones and zones with more stable
properties.
For example, we consider the conditions of formation Elan Bank in Kerguelen Plateau
structure. |
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