Zoned Grains in Moss CO3.6

The outer portion of some olivine grains in the Moss meteorites have levels of iron elevated above those in the center of the grains. This difference can be seen in some grains that have been thin sectioned. These photos are all of one rather small sample. All photos are in cross-polarized transmitted light.

This 3mm wide view shows may porphyritic chondrules and individual grains. The large blue euhedral crystal has a red center, that is, it is zoned. The oval chondrule below and right of center contains two similar though much smaller grains. The photo below is a closer view of the chondrule.

Porphyritic olivine chondrule containing two zoned grains. Field of view = 0.4mm wide.

Four zoned olivine grains. FOV=0.3mm wide.

Zoned olivine grain. FOV=0.4mm wide.

This grain appears to have been altered before it was broken and separated. FOV=0.3mm wide.

About the Author

John Kashuba
John is a natural history enthusiast living in Oregon.
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