Chert: Modern Inorganic Deposition in a Carbonate-Precipitating Locality.
Chert is precipitating as gelatinous opal-cristobalite in lakes associated with the Coorong Lagoon of South Australia. Dolomite, magnesite, and magnesian calcite are also being deposited. High pH (9.5 to 10.2) causes dissolution of detrital silicates; lowering of pH (7.0 to 6.5) and drying of the lakes cause precipitation of chert. time.
Peterson
M N
MN
Von Der Borch
C C
CC