Morphology of lava tumuli from Mendoza (Argentina), Patagonia (Argentina), and Al-Haruj (Libya)
The studied volcanic fields are associated with compound flows near the vents that are characterised by a tube network, sky lights, ephemeral vents and tumuli. During discontinuous activity discrete, channel-fed aa flow units in near-vent position often form fanshaped flow fields that resemble vents...
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| Autores principales: | , , , , |
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| Formato: | JOUR |
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_03728854_v52_n2_p181_Nemeth |
| Aporte de: |
| Sumario: | The studied volcanic fields are associated with compound flows near the vents that are characterised by a tube network, sky lights, ephemeral vents and tumuli. During discontinuous activity discrete, channel-fed aa flow units in near-vent position often form fanshaped flow fields that resemble vents effused by spatter-fed or clastogenic lava. These flows resulted from (a) reconstitution of fountain-generated spatter around vents by syn-depositional agglutination and coalescence, and (b) syn-eruptive collapse of rapidly grown spatter and scoria. In the studied lava shields three types of tumuli have been identified: (1) lava-coated tumuli, (2) upper-slope tumuli in near-source regions (both dominated in Libya), and (3) flowlobe tumuli in the distal areas (in all studied areas). The widespread flow-lobe tumuli in the studied fields confirm the general agreement of low lava-supply rates. Flow-lobe tumuli are interpreted to have been supplied with magma from tubes that originate in overflow from and through flank fissures connected with the lava lake of shield volcanoes. © 2008 Gebrüder Borntraeger. |
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