Summary
Acid rocks make up about 10% of the whole Tertiary volcanic pile in eastern Iceland, or some 800 km1 of rocks between sea level and the summit level. Approximately half are extrusive flows, which range in form from steep-sided domes to tabular flows and have individual volumes of up to 2.5 km1. Most of the other half consists of acid pyroclastic rocks, in which ignimbrites (pyroclastic flow deposits) and air-fall tuffs or agglomerates are equally abundant. Composite lavas and mix-lavas, in which basic and acid magmas were erupted together, are common and so are the corresponding minor intrusions and pyroclastic rocks.
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Paper read at the IAV International Symposium on Volcanology (New Zealand), scientific session of Nov. 27, 1965.
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Walker, G.P.L. Acid volcanic rocks in Iceland. Bull Volcanol 29, 375–402 (1966). https://doi.org/10.1007/BF02597164
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DOI: https://doi.org/10.1007/BF02597164