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Recent Mineralogy Graphs With Photos of Site
Click Graph For a Larger View
 Figure 1: Cr-spinel plot – several grains plot inside of the compostional field of chromite inclusions in diamond. Most grains are interpreted as having been derived from peridotitic source rocks, mostly likely spinel +/- garnet-bearing dunite, harzburgite, lherzolite and various pyroxenites as indicated by the distribution of data on Figure 2. |
 Figure 2: Cr-spinel plot indicating that most spinel grains likely were derived from garnet-spinel-bearing peridotites including dunite, harzburgite, lherzolite and various pyroxenites. Several grains plot well inside of the compositional field of chromite inclusions in diamond. |
 Figure 3: Olivine plot indicating a peridotitic paragenesis for most olivine grains. None are compositionally similar to komatiitic or picritic olivine. It is not possible, due to extensive compositional overlap, to distiguish between Mg-rich crustal olivine and relatively Mg-poor peridotitic olivine. |
 Figure 4: Olivine plot indicating a likely peridotitic origin for most olivine. The somewhat Fe-rich nature of the grains suggests, but does not prove, that the grains were derived from spinel-bearing peridotite. |
 Figure 5: Clinopyroxene plot indicating that most grains likely were derived from spinel lherzolite although two grains clearly are not and are interpreted as having been derived from garnet lherzolite. |
 Figure 6: Clinopyroxene geotherm calculated from electron microprobe analyses of single clinopyroxene grains. Solid diamonds are for clinopyroxene grains derived from garnet-perioditite and provide the only valid data points. Data from open triangle points can be projected onto the 50 mW/m2 geotherm to provide greater definition of it at lower pressures and temperatures than pressures and temperatures calculated from clinopyroxene grains derived from garnet-perioditite. |
Click to Enlarge Images
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 View of Creek Frontage |
 Creek frontage below exposed high crater facies of diatreme |
Contact Elinor O'Rourke -
530-532-7805
lynngems111@comcast.net
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