Imperial College London

Dr Craig Smalley

Faculty of EngineeringDepartment of Earth Science & Engineering

Visiting Professor
 
 
 
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Contact

 

c.smalley

 
 
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Location

 

Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Smalley:1983:10.1016/S0009-2541(83)80024-2,
author = {Smalley, PC and Field, D and Råheim, A},
doi = {10.1016/S0009-2541(83)80024-2},
journal = {Chemical Geology},
pages = {269--282},
title = {Resetting of Rb−Sr whole-rock isochrons during Sveconorwegian low-grade events in the Gjerstad augen gneiss, Telemark, southern Norway},
url = {http://dx.doi.org/10.1016/S0009-2541(83)80024-2},
volume = {41},
year = {1983}
}

RIS format (EndNote, RefMan)

TY  - JOUR
AB - The Gjerstad augen gneiss comprises a single igneous body that shows intrusive relationships to the surrounding older Telemark gneisses. The formation of the gneissic structure and augen texture was due to mylonitic deformation along a major shear zone, the Porsgrunn—Kristiansand fault zone. The augen gneiss can be divided petro-graphically into green, grey (both pyroxene-bearing) and pink types. Samples from three locations were analysed isotopically. Two distinct (at 2σ level) groups of ages were obtained which are interpreted as: (a) (~ 1250 Ma) cooling after high-temperature deformation and formation of retrogressive corona structures; (b) (~ 1080 Ma) resetting of whole-rock systems during low-grade mineral alteration by hydrous fluids. At ~ 900 Ma, there was further isotopic disturbance during low-grade alteration related to the intrusion of pegmatite veins. The significant age differences are not related to colour (= grade) of samples, and significantly different ages have been found in the same rock body within a single locality. As the Gjerstad augen gneiss was intruded before ~ 1250 Ma into a previously existing gneissic terrain, the gneiss-forming event and associated upper amphibolite facies metamorphism in the Gjerstad region is constrained to be pre ~ 1250 Ma, i.e. Pre-Sveco-norwegian. © 1983, Elsevier Science Publishers B.V.. All rights reserved.
AU - Smalley,PC
AU - Field,D
AU - Råheim,A
DO - 10.1016/S0009-2541(83)80024-2
EP - 282
PY - 1983///
SN - 0009-2541
SP - 269
TI - Resetting of Rb−Sr whole-rock isochrons during Sveconorwegian low-grade events in the Gjerstad augen gneiss, Telemark, southern Norway
T2 - Chemical Geology
UR - http://dx.doi.org/10.1016/S0009-2541(83)80024-2
VL - 41
ER -