Bowring's earlier analysis
of the zircons indicated they might have grown in two or more widely - spaced time periods, obscuring their exact age.
Not exact matches
The carbon contained in the
zircon has a characteristic signature — a specific ratio
of carbon - 12 to carbon - 13 — that
indicates the presence
of photosynthetic life.
I've used per tonne prices
of $ 18 for ilmenite, $ 100 for rutile, $ 133 for
zircon, a 50 % haircut for probable reserves, and 75 % for measured &
indicated resources.