Morphometry of glaciovolcanic edifices from Iceland: types and evolution

PEDERSEN, GRO B.M.; GROSSE, PABLO; GUDMUNDSSON, MAGNÚS T.

Nueva Orleans

Congreso; American Geophysical Union 2021 Fall Meeting; 2021

The morphology of glaciovolcanoes is considered one of the distinctive characteristics of their ice-confining eruption environment. Based on semi-automatic geomorphometric mapping and a 20 m resolution digital elevation model, we present a morphometric database of 155 glaciovolcanic edifices within the Icelandic neovolcanic zones.Using three planimetric measurements (basal length, average basal width and average summit plateau width) and their ratios, three main morphometric groups can be distinguished in a ternary diagram: 1) conical edifices with no or small summit plateaus, 2) linear ridges and 3) flat-topped edifices. All three groups contain edifices with and without lava caps. These groups fit the commonly accepted terminology for cone/mound, tindar and tuya, but since lava caps occur in all morphometric groups, a classification based on its existence is not practical.The glaciovolcanic edifice volumes range from 0.15 · 10−2 km3 to 32 km3. Conical edifices are the smallest (1 km3). Three morphological evolutions can be considered: (A) an initial eruptive fissure concentrates into one vent generating an equidimensional edifice, either conical or flat-topped; (B) the fissure is dominant during the eruption and a summit plateau develops, generating an elongated flat-topped edifice; and (C) the fissure remains active or lengthens during the eruption and a plateau-building stage does not occur, producing elongated ridges, often in the form of a row of peaks.