The progression of volcanism in the Samoan linear volcanic chain
Natland JH. 1980. The progression of volcanism in the Samoan linear volcanic chain. American Journal of Science. 280-A:709-735
The Samoan Islands are unique among the linear volcanic chains of the Pacific in that they are traversed by a single Pleistocene to historic volcanic rift zone for at least 300km across extinct, deeply eroded older shield volcanoes of the Samoan Ridge. Petrology criteria are established for distinguishing basalts of shiled volcanoes from post-erosional alkali olivine basalts, basanites, and olivine nephelinites and used to document the districtuion of post-erosional lavas along the chain. This distribution, the extent of erosion of shield volcanoes, the distribution of reefs, and paleomagnetic data all indicate that both the shield volcanoes and the post-erosional rift zone have propagated to the east; but post-erosional lavas are most voluminous at the western end of the island chain, giving islands there an anomalously youthful appearance.
- Type
- Journal Article
- Authors
- Natland, James
- Units
- NPSA , PACN
- Keywords
- American Samoa, Geology, Rift Zone, Volcanic Chain, Volcanology