• Corpus ID: 55008106

The Skagafjörður Volcanic Zone - An ephemeral Rift Zone

@inproceedings{Hjartarson2003TheSV,
  title={The Skagafj{\"o}rður Volcanic Zone - An ephemeral Rift Zone},
  author={{\'A}rni Hjartarson},
  year={2003}
}

• Á. Hjartarson
• Published 2003
• Geology

In the Skagafjorður district, North Iceland, an unconformity with a sedimentary layer divides the strata pile into Neogene and Pleistocene volcanic successions. Neogene volcanism faded out 4-5 Ma when the area drifted out of the volcanic zone near the diverging boundaries of the North American and Eurasian crustal plates, after which erosion took over for about a million years. Volcanism started again at the beginning of the Pleistocene. Lava flows covered the eroded Neogene landscape and an unconformity was formed. It is proposed that the Pleistocene volcanic rocks above the unconformity all belong to a short-lived axial rift zone, the Skagafjorður zone. Eruptive sites belonging to this zone can be found dispersed in the area between the Hofsjokull central volcano and the mouth of Skagafjorður. The oldest volcanic formations of the Pleistocene rock series are from about 1.7 Ma, when rifting in the area started. The activity culminated in the early Pleistocene but declined in the late Pleistocene, and in the Holocene the activity seems to have been restricted entirely to the Hofsjokull central volcano. A prominent fault and fissure system belongs to the Skagafjorður zone. The tectonics indicate extension. It is suggested that a decline in the activity of the Iceland Mantle Plume, 2-3 million years ago, caused a rift jump away from the hot spot below Vatnajokull and formation of a temporary rift zone, the Skagafjorður zone, which for a while bridged the shortest way between the Reykjanes-Langjokull zone and Kolbeinsey ridge.