May 4, 2009 Easter Island (aka Rapa Nui) is fascinating due to its remote location in the South Pacific Ocean and its cultural achievement, yielding hundreds of giant stone monoliths. Easter Island also stands out among intra-oceanic volcanic islands for certain remarkable geologic characteristics, such as its location close to the super-fast-spreading East Pacific Rise and above the Easter mantle plume.
Vezzoli and Acocella provide an overview of the geological and volcanotectonic evolution of Easter Island and discuss some general conceptual models of the formation and evolution of hot-spot oceanic islands.
Easter Island developed, in the past 0.7 million years, in two main stages. The first stage consisted of the build-up of three overlapping shield volcanoes, culminating in the formation of summit calderas.
The second stage was characterized by widespread fissural activity along the slopes of the shields. The reconstructed geologic features and volcanic evolution suggest that Easter Island is the expression of an end-member type of hot spot, characterized by low magmatic productivity, immature rift zones and scarce sector collapses, the opposite of what is found in the Hawaiian Islands.
This research was published by Luigina Vezzoli and Valerio Acocella (Universita degli Studi dell'Insubria, Dipartimento di Scienze Chimiche e Ambientali, via Valleggioin) the May-June issue of GSA Bulletin.
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- Luigina Vezzoli and Valerio Acocella. Easter Island, SE Pacific: An end-member type of hotspot volcanism. Geological Society of America Bulletin, 2009; 121 (5-6): 869 DOI: 10.1130/B26470.1
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