Image 5:
Images on this page were acquired using the UMass Dept. of Geosciences'
Cameca SX-50 electron microprobe.
Caption:
The subject is a garnet and surrounding matrix from a manganiferous supraophiolitic
quartzose schist from ultrahighpressure Lago di Cignana locality, Valtournenche,
Italy. ( Pmax >25 kbar, Tmax ca. 600 deg.C. : Reinecke, T. (1991) Very-high
pressure metamorphism and uplift of coesite-bearing metasediments from
the Zermatt-Saas zone, Western Alps. Eur. J. Mineral., 3, 7-17.))
The matrix assemblage includes quartz (after coesite), phengite (Si
ca. 3.4 pfu), Mn-rich phlogopite, piemontite and Mn-rich calcite. Inclusions
in this garnet are piemontite and quartz.
Note particularly the compositional angular unconformity between
core and overgrowth.
For more information about this image contact: Michael
L. Williams