Table T2. Results of repeated opal measurements in regard to the analytical precision of the method.

Core, section,
interval (cm)
Numbers
Mean
(wt% SiO2)
Standard
deviation
(wt% SiO2)
Coefficient
of variation
(%)
178-1095B-4H-5, 74-75 12 19.8 2.7 3.9
178-1096A-8H-7, 16-18 15 1.8 0.2 2.3
178-1096B-9H-2, 10-12 14 2.9 0.5 4.4