Evidence for a differentiated ignimbritic activity ending the building-stage of Tahiti-Nui (French Polynesia) |
| |
Authors: | Anthony Hildenbrand Pierre-Yves Gillot |
| |
Institution: | Géochronologie multi-techniques, UMR 8148 IDES, bât. 504, Sciences de la Terre, université Paris-Sud, 91405 Orsay, France |
| |
Abstract: | A thick columnar-jointed ignimbrite-like formation occupies the upper part of the Orohena Massif on Tahiti-Nui. Differentiated products related to the ignimbrite were sampled at the base of the Orohena cliff and have been dated using the unspiked K/Ar Cassignol technique at . These pyroclastic volcanic rocks show chemical similarities with Ne-syenitic rocks from a shallow magma reservoir presently exposed farther south because of the dissection of the island by deep erosion. The presence of less-evolved magma blebs in the ignimbrite products suggests an incomplete magma mixing process. This likely indicates a late injection of a more basic magma into the reservoir, probably triggering the ignimbritic eruption, unique in the generally non-explosive eruptive history of Tahiti-Nui. To cite this article: A. Hildenbrand, P.-Y. Gillot, C. R. Geoscience 338 (2006). |
| |
Keywords: | Tahiti-Nui Ignimbrite Differentiation Basic re-injection Tahiti-Nui Ignimbrite Différenciation Réinjection basique |
本文献已被 ScienceDirect 等数据库收录! |
|