Article
 

The Cobb-Eickelberg seamount chain : hotspot volcanism with mid-oean ridge basalt affinity

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/articles/4x51hk59f

Descriptions

Attribute NameValues
Creator
Abstract
  • Cobb hotspot, currently located beneath Axial seamount on the Juan de Fuca ridge, has the temporal but not the isotopic characteristics usually attributed to a mantle plume. The earlier volcanic products of the hotspot, from eight volcanoes in the Cobb-Eickelberg seamount (CES) chain, show a westward age progression away from the hotspot and a westward increase in the age difference between the seamounts and the crust on which they formed. These results are consistent with movement of the Pacific plate over a fixed Cobb hotspot and eventual encroachment by the westwardly migrating Juan de Fuca ridge. CES lavas are slightly enriched in alkalies and incompatible elements relative to those of the Juan de Fuca ridge but they have Sr. Nd, and Pb isotopic compositions virtually identical to those found along the ridge. Therefore, Cobb hotspot is a stationary, upper mantle melting anomaly whose volcanic products show strong mid-ocean ridge basalt (MORB) affinity. These observations can be explained by low degrees of partial melting of entrained heterogeneous upper mantle MORB source material within a thermally driven lower mantle diapir or by an intrinsic MORB-like composition of the deeper mantle source region from which northeast Pacific plumes rise.
  • Keywords: Cobb-Eickelberg Seamount Chain, Hotspot volcanism
Resource Type
DOI
Date Available
Date Issued
Citation
  • Desonie, D. L., and Duncan, R. A., (1990). The Cobb-Eickelberg seamount chain: hotspot volcanism with mid-ocean ridge basalt affinity. J. Geophys. Res., 95, B8, 12,697-12,711.
Journal Title
Journal Volume
  • 95
Rights Statement
Publisher
Language
Replaces

Relationships

Parents:

This work has no parents.

Items

Thumbnail Title Date Uploaded Visibility Actions
file details Desonie_and_Duncan_JGR_1990.pdf 2017-07-24 Public Download