New 40Ar/39Ar age and geochemical data from seamounts in the Canary and Madeira volcanic provinces; support for the mantle plume hypothesis

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doi: 10.1016/j.epsl.2005.04.037
Authors:Geldmacher, J.; Hoernle, K.; van den Bogaard, P.; Duggen, S.; Werner, R.
Author Affiliations:Primary:
IFM-GEOMAR Leibniz-Institut für Meereswissenschaften, Dynamics of the Ocean Floor, Kiel, Federal Republic of Germany
Other:
University of Copenhagen, Denmark
TETHYS Geoconsulting Gmbh, Federal Republic of Germany
Volume Title:Earth and Planetary Science Letters
Source:Earth and Planetary Science Letters, 237(1-2), p.85-101. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X
Publication Date:2005
Note:In English. 67 refs.; illus., incl. 2 tables, geol. sketch maps
Summary:The role of mantle plumes in the formation of intraplate volcanic islands and seamount chains is being increasingly questioned. Particular examples are the abundant and somewhat irregularly distributed island and seamount volcanoes off the coast of northwest Africa. New 40Ar/39Ar ages and Sr-Nd-Pb isotope geochemistry of volcanic rocks from seamounts northeast of the Madeira Islands (Seine and Unicorn) and northeast of the Canary Islands (Dacia and Anika), however, provide support for the plume hypothesis. The oldest ages of shield stage volcanism from Canary and Madeira volcanic provinces confirm progressions of increasing age to the northeast. Average volcanic age progression of ∼1.2 cm/a is consistent with rotation of the African plate at an angular velocity of ∼0.20°EPM0.05 /Ma around a common Euler pole at approximately 56°N, 45°W computed for the period of 0-35 Ma. A Euler pole at 35°N, 45°W is calculated for the time interval of 35-64 Ma. The isotope geochemistry further confirms that the Madeira and Canary provinces are derived from different sources, consistent with distinct plumes having formed each volcanic group. Conventional hotspot models, however, cannot easily explain the up to 40 m.y. long volcanic history at single volcanic centers, long gaps in volcanic activity, and the irregular distribution of islands and seamounts in the Canary province. A possible explanation could involve interaction of the Canary mantle plume with small-scale upper mantle processes such as edge-driven convection. Juxtaposition of plume and non-plume volcanism could also account for observed inconsistencies of the classical hotspot concept in other volcanic areas. Abstract Copyright (2005) Elsevier, B.V.
Sections:Age determination; Geochemistry
Subsections:Igneous rocks
Subjects:Absolute age; African Plate; Alkaline earth metals; Ar/Ar; Basalts; Cenozoic; Convection; Dates; Fracture zones; Hot spots; Igneous rocks; Intraplate processes; Islands; Isotopes; Lead; Mantle; Mantle plumes; Metals; Models; Neodymium; Ocean-island basalts; Paleogene; Plate rotation; Rare earths; Seamounts; Strontium; Tertiary; Upwelling; Volcanic rocks; Volcanism; Atlantic Ocean; Atlantic Ocean Islands; Canary Islands; East Atlantic; Madeira; Anika Seamount; Dacia Seamount; Seine Seamount; Unicorn Seamount
Coordinates:N344725 N344725 W0143500 W0143500
N335204 N335204 W0142208 W0142208
N311718 N311718 W0134437 W0134437
N311337 N311337 W0134503 W0134503
N313427 N313427 W0125904 W0125904
Abstract Numbers:05M/3633
Record ID:2006039026
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands
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