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San Jacinto Intrusive Complex: 3. Constraints on crustal magma chamber processes from strontium isotope heterogeneity

Hill, R. I. and Silver, L. T. (1988) San Jacinto Intrusive Complex: 3. Constraints on crustal magma chamber processes from strontium isotope heterogeneity. Journal of Geophysical Research B, 93 (B9). pp. 10373-10388. ISSN 0148-0227. http://resolver.caltech.edu/CaltechAUTHORS:20131031-103755851

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Abstract

Strontium isotope data from three large plutons interpreted as derived from dynamic magma chambers (Hill, this issue; Hill et al., this issue) show the existence of pronounced isotopic heterogeneity within each unit. Ranges of calculated initial ^(87)Sr/^(86)Sr are unit I, 0.7060–0.7076; unit II, 0.7060–0.7074; unit III, 0.7058–0.7073. A limited sample of mafic inclusions and dyke rocks, interpreted as samples of liquid added to the various chambers during inflation, have initial ^(87)Sr/^(86)Sr of 0.7068–0.7084. These variations are regular at the kilometer scale within each pluton and show no identified correlation with any other observed geochemical or petrological parameter. Slightly older small intrusions that span the compositional range olivine gabbro to granite show a systematic increase in initial ^(87)Sr/^(86)Sr from 0.7057 in the southwest to 0.7077 in the northeast, expressing the pattern previously reported for the northern 600 km of the Peninsular Ranges batholith. The Sr isotope data indicate that melt production, aggregation, transport, and crystallization processes were far from capable of completely homogenizing initial variations in initial ^(87)Sr/^(86)Sr within the liquids from which these rocks crystallized. Whole chamber convection is apparently ruled out by these data; more complex patterns, including double-diffusively induced horizontal stratification, are permitted.


Item Type:Article
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http://dx.doi.org/10.1029/JB093iB09p10373 DOIArticle
http://onlinelibrary.wiley.com/doi/10.1029/JB093iB09p10373/abstractPublisherArticle
Additional Information:© 1988 by the American Geophysical Union. Received November 26, 1984; revised October 23, 1986; accepted February 27, 1987. Financial support was provided by National Science Foundation grants EAR 76-23153 and EAR 77-23507 to L.T.S., by Department of Energy contract DE-AC13-76 GJO 1664, Bendix Field Engineering Corp. subcontract 79- 384-E to L.T.S, and by a Conoco Fellowship and the Division of Geological and Planetary Sciences, California Institute of Technology for R.I.H. Discussions with Steve Sparks have materially assisted in the writing of this report, as have detailed reviews, and comments from Mike Dungan and Wes Hildreth. Contribution 4162 of the Division of Geological and Planetary Sciences, California Institute of Technology.
Funders:
Funding AgencyGrant Number
NSFEAR 76-23153
NSFEAR 77-23507
Department of Energy (DOE)DE-AC13-76 GJO 1664
Bendix Field Engineering Corp.79-384-E
Conoco FellowshipUNSPECIFIED
Caltech Division of Geological and Planetary SciencesUNSPECIFIED
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Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences4162
Record Number:CaltechAUTHORS:20131031-103755851
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20131031-103755851
Official Citation:Hill, R. I., and L. T. Silver (1988), San Jacinto Intrusive Complex: 3. Constraints on crustal magma chamber processes from strontium isotope heterogeneity, J. Geophys. Res., 93(B9), 10373–10388, doi:10.1029/JB093iB09p10373
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42153
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:31 Oct 2013 21:45
Last Modified:31 Oct 2013 21:45

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