thumbnail

Botanical and geological significance of potassium-argon dates from the Juan Fernández Islands

Science

By:
, , , , and
DOI: 10.1126/science.225.4657.49

Links

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.

Additional Publication Details

Publication type:
Article
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