Viking Age Iceland: Dating the Settlement: Volcanic Ash Layers

A picture of Leif Eirksson's statue in Reykjavík, Iceland

This 61 of our ongoing series about Viking Age Iceland. For centuries, this island country, unique in Medieval Europe, operated with no king, no great lords, no foreign policy, and no defense forces but which developed legal and judicial systems to limit the violence of bloodfeud and protect the rights of freemen. Far out in the North Atlantic, Iceland was where the famous sagas developed. To explore Iceland’s place in the medieval world, we present selections from Jesse Byock’s Viking Age Iceland that investigate the history, archaeology, culture, systems of feud, and sagas of this magical place.

Iceland’s settlement is traditionally dated to around 870. This dating originally relied solely on the written sources, especially the twelfth-century Book of the Icelanders. Today it is reinforced by archaeological finds whose dates are often successfully established by stratigraphic comparisons with volcanic tephra (ash) layers.[i] Tephra, a generic term for solid particles thrown out from a volcanic eruption, includes ash, rock fragments, pumice and large stones. Because tephra layers are widely dispersed by winds, similar layers can be compared in different areas. Often they can be referenced to historical records and serve as a reliable means of establishing chronology. The layers striate the soil, and tephra is often easily seen in soil profiles on the sides of simple trenches dug during archaeological or geological work. Because the various tephras are composed of different elements, coming from different volcanic systems, including Hekla, Katla, and the Vatnaöldur fissure, they have identifiable trace-element signatures. Icelandic geologists have correlated the most widely distributed layers found in soil profiles throughout Iceland into a comprehensive system useful for dating over a wide area of the North Atlantic, wherever Icelandic volcanic ash was carried by the wind.

A tephra layer which is especially important for Viking Age excavations is that known as the landnám tephra. Through comparisons of trace elements found in ice-core samples drilled from the Greenlandic ice pack, the landnám tephra layer is dated to 871 ± 2 and effectively marks the start of Iceland’s settlement.[ii] There is no evidence of human impact on the landscape in the soil below the landnám tephra. When trenches are dug in boggy ground[IS1] , it’s often easy to see[IS2]  the difference between the rich undisturbed organic landscapes immediately below the landnám tephra layer [IS3] and the far more sterile soils (often the result [IS4] of erosion and the effects of human habitation) immediately above,[iii] as in the marshy valley bottom at Mosfell. Two other tephra layers, the Katla R tephra of c. 920 and the Eldgjá tephra of about 935, mark the end of the settlement period in about 930. Remains from the later Free State period are also frequently datable by what is known as the medieval tephra layer of about 1226, which is thought to have resulted from an eruption off Iceland’s south-western coast.

Although the geological evidence agrees with archaeological finds about the dating of the major migration, it is also reasonable to assume that at least a few people, aside from the previously mentioned Irish monks seeking solitude, would have washed up on the shores of such a big island before the 870s. In any event, our understanding of the basic process of colonization beginning in the ninth-century Viking Age does not depend on an exact date.

[i] Sigurður Thórarinsson 1981; Guðrún Larsen 1996; Dugmore and Simpson 1999.

[ii] Grönvold 1994; Grönvold et al. 1995; Guðrún Larsen 1996.

[iii] Buckland et al. 1995; Dugmore and Simpson 1999.

 [IS1]MS had ‘into swampy lands’

 [IS2]MS had ‘one often easily sees’

 [IS3]Added in VAI 2001

 [IS4]MS had ‘product’

— Jesse Byock, Viking Age Iceland

Published by Jules William Press

Jules William Press is a small press devoted to publishing the best about the Viking Age, Old Norse, and the Atlantic and Northern European regions. Jules William Press was founded in 2013 to address the needs of modern students, teachers, and self-learners for accessible and affordable Old Norse texts. JWP began by publishing our Viking Language Series, which provides a modern course in Old Norse, with exercises and grammar that anyone can understand. This spirit motivates all of our publications, as we expand our catalogue to include Viking archaeology and history, as well as Scandinavian historical fiction and our Saga Series.

%d bloggers like this: