skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Geology and petrogeneses of the lavas of Floreana and Santa Cruz Islands: Galapagos Archipelago

Abstract

Floreana is a mature shield volcano situated on the southern boundary scarp of the Galapagos Platform. On the basis of petrographic and geochemical criteria, Floreana lavas are divisible into two distinct volcanic series: Main Series: Fine-grained, alkalic basanitoids constitute the majority of shield-building flows. Flank Series: Isolated parasitic shields on the southeastern flank of the central volcano erupted olivine and plagioclase phyric, alkali-poor basanitoid lavas during the waning stages of volcanism. A spectrum of theoretical models was applied to the Floreana suite in an attempt to account for observed major and trace element variations. The complex tectonic history and chemical diversity of volcanism on Santa Cruz contrasts with the relative brevity and compositional uniformity of volcanism on Floreana. Two major time-stratigraphic units are defined for Santa Cruz lavas. Platform Series: Lavas are dominantly olivine tholeiites and ferrobasalts with little compositional diversity; subsidiary low-K/sub 2/O ridge type basalts and basanitoid lavas have affinities with younger, Shield Series rocks. Lavas associated with this most recent phase of Santa Cruz volcanism include basanitoids (alkali-olivine basalts), hawaiites, low-K/sub 2/O basalts, and flows with compositions intermediate between basanitoid and low-K/sub 2/O types. The results of petrogenetic modeling for Floreana and Santa Cruz imply significant lateralmore » variations in mantle trace element abundances, depth, and extent of partial melting and volcanic plumbing systems. These patterns are reflected to varying extents by other volcano-tectonic provinces and may be consequences of the thermal evolution of mantle melting anomalies.« less

Authors:
Publication Date:
Research Org.:
Oregon Univ., Eugene (USA)
OSTI Identifier:
5473189
Alternate Identifier(s):
OSTI ID: 5473189
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; LAVA; GEOLOGY; PETROGENESIS; ANORTHOSITES; BASALT; CHROMIUM; EARTH CRUST; EARTH MANTLE; ELEMENTS; NICKEL; OLIVINE; ORIGIN; POTASSIUM OXIDES; RARE EARTH COMPOUNDS; STRATIGRAPHY; TECTONICS; TRACE AMOUNTS; VOLCANOES; ALKALI METAL COMPOUNDS; ALKALINE EARTH METAL COMPOUNDS; CHALCOGENIDES; GABBROS; IGNEOUS ROCKS; IRON COMPOUNDS; IRON SILICATES; MAGNESIUM COMPOUNDS; MAGNESIUM SILICATES; METALS; MINERALS; OXIDES; OXYGEN COMPOUNDS; PLUTONIC ROCKS; POTASSIUM COMPOUNDS; ROCKS; SILICATE MINERALS; SILICATES; SILICON COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; TRANSITION ELEMENTS; VOLCANIC ROCKS 580202* -- Geophysics-- Volcanology-- (1980-1989)

Citation Formats

Bow, C.S. Geology and petrogeneses of the lavas of Floreana and Santa Cruz Islands: Galapagos Archipelago. United States: N. p., 1979. Web.
Bow, C.S. Geology and petrogeneses of the lavas of Floreana and Santa Cruz Islands: Galapagos Archipelago. United States.
Bow, C.S. Mon . "Geology and petrogeneses of the lavas of Floreana and Santa Cruz Islands: Galapagos Archipelago". United States.
@article{osti_5473189,
title = {Geology and petrogeneses of the lavas of Floreana and Santa Cruz Islands: Galapagos Archipelago},
author = {Bow, C.S.},
abstractNote = {Floreana is a mature shield volcano situated on the southern boundary scarp of the Galapagos Platform. On the basis of petrographic and geochemical criteria, Floreana lavas are divisible into two distinct volcanic series: Main Series: Fine-grained, alkalic basanitoids constitute the majority of shield-building flows. Flank Series: Isolated parasitic shields on the southeastern flank of the central volcano erupted olivine and plagioclase phyric, alkali-poor basanitoid lavas during the waning stages of volcanism. A spectrum of theoretical models was applied to the Floreana suite in an attempt to account for observed major and trace element variations. The complex tectonic history and chemical diversity of volcanism on Santa Cruz contrasts with the relative brevity and compositional uniformity of volcanism on Floreana. Two major time-stratigraphic units are defined for Santa Cruz lavas. Platform Series: Lavas are dominantly olivine tholeiites and ferrobasalts with little compositional diversity; subsidiary low-K/sub 2/O ridge type basalts and basanitoid lavas have affinities with younger, Shield Series rocks. Lavas associated with this most recent phase of Santa Cruz volcanism include basanitoids (alkali-olivine basalts), hawaiites, low-K/sub 2/O basalts, and flows with compositions intermediate between basanitoid and low-K/sub 2/O types. The results of petrogenetic modeling for Floreana and Santa Cruz imply significant lateral variations in mantle trace element abundances, depth, and extent of partial melting and volcanic plumbing systems. These patterns are reflected to varying extents by other volcano-tectonic provinces and may be consequences of the thermal evolution of mantle melting anomalies.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1979},
month = {1}
}

Thesis/Dissertation:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this thesis or dissertation.

Save / Share: