caa a22 4500 477062288 CHVBK 20180405111404.0 cr unu---uuuuu 170330e19960401xx s 000 0 eng 10.1007/BF00304437 doi (NATIONALLICENCE)springer-10.1007/BF00304437 Rossi M. Nordic Volcanological Institute, Geoscience Building, University of Iceland, IS-101, Reykjavik, Iceland aut Morphology and mechanism of eruption of postglacial shield volcanoes in Iceland [Elektronische Daten] [M. Rossi] Postglacial Icelandic shield volcanoes were formed in monogenetic eruptions mainly in the early Holocene epoch. Shield volcanoes vary in their cone morphology and in the areal extent of the associated lava flows. This paper presents the results of a study of 24 olivine tholeiite and 7 picrite basaltic shield volcanoes. For the olivine tholeiitic shields the median slope is 2.7°, the median height 60 m, the median diameter 3.6 km, the median aspect ratio (height against diameter) 0.019, and the median cone volume 0.2 km3. The picritic shield volcanoes are considerably steeper and smaller. A shield-volcano cone forms from successive lava lake overflows which are of shelly-type pahoehoe. A widespread apron surrounding the cone forms from tube-fed P-type pahoehoe. The slopes of the cones have (a) a planar or slightly convex form, (b) a concave form, or (c) a convex-concave form. A successive stage of a shield volcano is determined on the basis of cone morphology and lava assemblages. A shield-producing eruption has alternating episodes of lava lake overflows and tube-fed delivery to the distal parts of the flow field. In the late stages of eruption, the cone volume increases in response to the increased amount of rootless outpouring on the cone flanks. Normally, only a small percentage of the total erupted volume of a shield volcano, sometimes as little as 1-3%, is in the shield volcano cone itself, the main volume being in the apron of the shield. Springer-Verlag, 1996 Shield volcanoes nationallicence Lava flows nationallicence Lava tubes nationallicence Craters nationallicence Morphology nationallicence Basalt nationallicence Iceland nationallicence Bulletin of Volcanology Springer-Verlag 57/7(1996-04-01), 530-540 0258-8900 57:7<530 1996 57 445 https://doi.org/10.1007/BF00304437 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00304437 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Rossi M. Nordic Volcanological Institute, Geoscience Building, University of Iceland, IS-101, Reykjavik, Iceland aut NATIONALLICENCE 773 0- Bulletin of Volcanology Springer-Verlag 57/7(1996-04-01), 530-540 0258-8900 57:7<530 1996 57 445 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer