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Conditions for emerald formation at Davdar, China: fluid inclusion, trace element and stable isotope studies

Published online by Cambridge University Press:  05 July 2018

D. Marshall ,
V. Pardieu ,
L. Loughrey ,
P. Jones  and
G. Xue
D. Marshall*
Affiliation:
Earth Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
V. Pardieu
Affiliation:
GIA Laboratory, 10th Floor, 968 Rama IV Rd., Silom Bangrak, Bangkok 10500, Thailand
L. Loughrey
Affiliation:
Earth Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
P. Jones
Affiliation:
Earth Sciences, Carleton University, Ottawa, Ontario K1S 5B6, Canada
G. Xue
Affiliation:
Earth Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
*
*E-mail: [email protected]
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Abstract

Preliminary geological work on samples from Davdar in China indicate that emerald occurs in quartz veins hosted within upper greenschist grade Permian metasedimentary rocks including quartzite, marble, phyllite and schist. Fluid inclusion studies indicate highly saline fluids ranging from approximately 34 to 41 wt.% NaCl equivalent, with minimal amounts of CO2 estimated at a mole fraction of 0.003. Fluid inclusion, stable isotope and petrographic studies indicate the Davdar emeralds crystallized from highly saline brines in greenschist facies conditions at a temperature of ∼350°C and a pressure of up to 160 MPa. The highly saline fluid inclusions in the emeralds, the trace-element chemistry and stable isotope signatures indicate that the Davdar emeralds have some similarities to the Khaltaro and Swat Valley emerald deposits in Pakistan, but they show the greatest similarity to neighbouring deposits at Panjshir in Afghanistan.

Keywords

berylChinaDavdaremeraldfluid inclusion studiesgreenschist faciesstable isotope geochemistry
Type
Research Article
Information
Mineralogical Magazine , Volume 76 , Issue 1 , February 2012 , pp. 213 - 226
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2012

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