Abstract
A plot of Ce/Yb vs. Ba/Ce, for locality averages, effectively separates mid-ocean ridge basalts (MORB) (Ce/Yb 10, Ba/Ce 4.2). The conventional interpretation is that these three types of volcanic environments involve oceanic rift-related, large-volume partial melts (˜20-30%) of a depleted source (MORB), small volume melts (˜5% for alkalic volcanics) of enriched sources related to plumes (OIV), and melts of hydrous-enriched sources during subduction, especially for Ba (IAV). Three OIV sites, however, have average ratios that fall in the MORB field (e.g., Krafla Volcano, Iceland), and these localities also tend to have other geochemical data similar to MORB. Average ratios of Hawaiian tholeiitic shield basalts of Mauna Kea and Koolau volcanoes occupy a restricted field on a plot of Ce/Yb vs. Ba/Ce of 10-18 for Ce/Yb and 2.8-3.1 for Ba/Ce, a field toward which ...
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