Botanical and geological significance of potassium-argon dates from the Juan Fernández Islands
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Abstract
Potassium-argon dating of five basalts from the three main islands of the Juan Fernández (or Robinson Crusoe) Islands of Chile in the southeastern Pacific gives ages of 1.01 ± 0.12 and 2.44 ± 0.14 million years for Masafuera, 3.79 ± 0.20 and 4.23 ± 0.16 for Masatierra, and 5.8 ± 2.1 for Santa Clara. These ages are much younger than that of the underlying oceanic plate and are consistent with the origin of the island-seamount chain from a mantle hot spot beneath the eastward moving Nazca plate. The young age for the archipelago suggests that speciation within endemic genera has occurred within the past 4 to 5 million years. Endemic genera of apparently more ancient origins, such as Lactoris and Thyrsopteris, have apparently dispersed to the islands and survive refugially.
Publication type | Article |
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Publication Subtype | Journal Article |
Title | Botanical and geological significance of potassium-argon dates from the Juan Fernández Islands |
Series title | Science |
DOI | 10.1126/science.225.4657.49 |
Volume | 225 |
Issue | 4657 |
Year Published | 1984 |
Language | English |
Publisher | AAS |
Description | 3 p. |
First page | 49 |
Last page | 51 |
Online Only (Y/N) | N |
Additional Online Files (Y/N) | N |
Google Analytic Metrics | Metrics page |