|
|||||
|
|
Resolving Sediment Subduction and Crustal Contamination in the Lesser Antilles Island Arc: a Combined He-O-Sr Isotope Approach |
|
| Authors: | VAN SOEST MATTHIJS C; HILTON DAVID R; MACPHERSON COLIN G; MATTEY DAVID P |
| Institution: | 1DEPARTMENT OF EARTH SCIENCES, VRIJE UNIVERSITEIT AMSTERDAM, DE BOELELAAN 1085, 1081 HV AMSTERDAM, THE NETHERLANDS 2GEOSCIENCES RESEARCH DIVISION, SCRIPPS INSTITUTION OF OCEANOGRAPHY, LA JOLLA, CA 92093-0244, USA 3DEPARTMENT OF GEOLOGICAL SCIENCES, UNIVERSITY OF DURHAM, SOUTH ROAD, DURHAM DH1 3LE, UK 4DEPARTMENT OF GEOLOGY, ROYAL HOLLOWAY, UNIVERSITY OF LONDON, EGHAM HILL, EGHAM TW20 0EX, UK |
| Abstract: | We report an extensive helium isotope survey of basaltic toandesitic lavas from the Lesser Antilles island arc—anarc system with well-documented evidence of crustal contamination.Given the sensitivity of helium isotopes as a tracer of theeffects of crustal additions, our aim is to evaluate the relationshipof 3He/4He ratios to other indices of contamination processessuch as oxygen and strontium isotopes. To this end, we havecarried out 53 3He/4He analyses on separated minerals (olivinesand pyroxenes) from throughout the arc, which we compare withwhole-rock strontium and phenocryst oxygen isotope measurements.We show that the three isotopic tracers show coherent patternsthroughout the Lesser Antilles, indicating a regional controlon crustal contamination. The southern section of the arc (Grenadato Martinique) shows clear evidence for major crustal contaminationin all three isotopic systems with results for our samples inthe range 3He/4He(olivine) 3·6–7·6RA, |
| Keywords: | |
| 本文献已被 Oxford 等数据库收录！ | |