thumbnail

Petrology of ultramafic xenoliths from Loihi Seamount, Hawaii

Journal of Petrology

By:

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time
  • Download citation as: RIS

Abstract

Ultramafic xenoliths were recovered in four alkalic lava flows from Loihi Seamount at depths between 2200 and 1400 m. No xenolith bearing flows were sampled near the summit despite a concentrated dredge program. The flows, three of alkalic basalt and one of basanite, contain common olivine megacrysts and small xenoliths of dunite, rarer harzburgite, and a single wehrlite. Olivine megacrysts as large as 8 mm are Fo84-88.6 and contain magnesiochromite inclusions with 1.1-3.5 wt.% TiO2. Dunite contains Fo83.5-88.5 olivine, meganesiochromite with 1.5-6.9 wt.% TiO2 (avg. 3.2 wt.), and extremely rare chrome-rich diopside. The wehrlite contains euhedral Fo85.9 olivine and magnesiochromite with 1.9-4.7 wt.% TiO2, poikilitically enclosed in chrome-rich diposide (Wo45.4En48.0s6.6). Most of the olivine megacrysts, dunite, and the wehrlite are cumulates of Loihi alkalic lavas that accumulated in a magma storage zone located at least 16 km below sea level. The rarity of dunite related to tholeiitic magmas supports the interpretation that the alkalic lavas at Loihi generally predate the tholeiitic lavas. -from Author

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Petrology of ultramafic xenoliths from Loihi Seamount, Hawaii
Series title:
Journal of Petrology
Volume
29
Issue:
6
Year Published:
1988
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Petrology
First page:
1161
Last page:
1186
Number of Pages:
26