A Tale of Two Planets
- Creators
- Anderson, Don L.
Abstract
Most of Earth's volcanism occurs at plate boundaries—mid-ocean ridges and island arcs. Most of the ^3He and other noble gases also are expelled from the interior at these locations. A small amount, compared to the global budget, of magma (<10%) and ^3He («1%) escapes at mid-plate volcanoes, the so-called "hotspots." Locations of hotspots are controlled by stresses and cracks, not by deep, narrow mantle upwellings. Most, or all, of Earth's volatile inventory appears to have been brought in by a late veneer. The high ^3He content and high He/Ne and He/Ar ratios of mid-ocean ridge basalts, plus the excess ^(129)Xe and ^(136)Xe, suggest that the ridge basalt reservoir is relatively undegassed and that there is no primordial undegassed reservoir. The two prevailing views of the origin of Earth are summarized in the context of this information.
Additional Information
© 1999 by V. H. Winston & Son. Inc. Version of record first published: 06 Jul 2010.Additional details
- Eprint ID
- 34822
- DOI
- 10.1080/00206819909465190
- Resolver ID
- CaltechAUTHORS:20121010-112755565
- Created
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2012-10-10Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field