Because of extensive volcanic production in Iceland during Holocene, many of the early postglacial large-volume fissure lavas cannot be traced easily to their eruptive crater solely by observations in the field.
Vegna tíðra eldgosa á Nútíma þá reynist oft erfitt að rekja stórar hraunbreiður til upptaka sinna aðeins út frá athugunum í mörkinni.