caa a22 4500 477062210 CHVBK 20180405111404.0 cr unu---uuuuu 170330e19960401xx s 000 0 eng 10.1007/BF00304439 doi (NATIONALLICENCE)springer-10.1007/BF00304439 Deformation patterns in a high-viscosity lava flow inferred from the crystal preferred orientation and imbrication structures: an example from Salina (Aeolian Islands, southern Tyrrhenian Sea, Italy) [Elektronische Daten] [G. Ventura, R. De Rosa, E. Colletta, R. Mazzuoli] Shape-preferred orientation and imbrication structures of crystals have been measured on samples representative of the base, centre and top of a highly viscous lava flow on Salina (Aeolian Islands, southern Tyrrhenian Sea). The data allow zones with different deformation patterns to be identified. In the base and top of the flow, deformation leads to the development of discrete preferred orientation and imbrication of the elongate crystals. The sense of shear is right-lateral at the base and left-lateral at the top of the flow. Shear strain can be estimated by the analysis of crystal preferred orientation. Deformation increases from the flow centre to the outer, more viscous boundary layers. Random orientation of crystals in the inner zone supports the presence of plug flow in a pseudoplastic lava. The textural features of the studied lava may be related to different mechanisms (i.e. lateral expansion). We conclude that the observed crystal alignments and imbrication structures may be related to a plug flow moving between two non-deforming walls. The walls are represented by the solidified, broken upper and basal crust of the flow. The low shear strain values calculated in the outer margins of the flow are indicative of the last deformation event. Crystal preferred orientation and imbrication structures may be related to the occurrence of velocity gradients existing between the inner zone of the flow and its solidus or near-solidus outer margins. Springer-Verlag, 1996 Lava flow nationallicence Crystal preferred orientation Deformation nationallicence Simple shear nationallicence Bingham/viscoplastic flows nationallicence Ventura G. Osservatorio Vesuviano, Via Osservatorio, I-80056, Ercolano (NA), Italy aut De Rosa R. Dipartimento Geomineralogico, Università di Bari, Via Orabona, Campus Universitario, I-70121, Bari, Italy aut Colletta E. Dipartimento Scienze della Terra, Università della Calabria, I-87036, Areavacata di Rende (CS), Italy aut Mazzuoli R. Dipartimento Scienze della Terra, Università di Pisa, Via S. Maria 53, I-56100, Pisa, Italy aut Bulletin of Volcanology Springer-Verlag 57/7(1996-04-01), 555-562 0258-8900 57:7<555 1996 57 445 https://doi.org/10.1007/BF00304439 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00304439 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ventura G. Osservatorio Vesuviano, Via Osservatorio, I-80056, Ercolano (NA), Italy aut NATIONALLICENCE 700 1- De Rosa R. Dipartimento Geomineralogico, Università di Bari, Via Orabona, Campus Universitario, I-70121, Bari, Italy aut NATIONALLICENCE 700 1- Colletta E. Dipartimento Scienze della Terra, Università della Calabria, I-87036, Areavacata di Rende (CS), Italy aut NATIONALLICENCE 700 1- Mazzuoli R. Dipartimento Scienze della Terra, Università di Pisa, Via S. Maria 53, I-56100, Pisa, Italy aut NATIONALLICENCE 773 0- Bulletin of Volcanology Springer-Verlag 57/7(1996-04-01), 555-562 0258-8900 57:7<555 1996 57 445 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer