N. Allison, GEOCHEMICAL ANOMALIES IN CORAL SKELETONS AND THEIR POSSIBLE IMPLICATIONS FOR PALEOENVIRONMENTAL ANALYSES, Marine chemistry, 55(3-4), 1996, pp. 367-379
Different features are visible when thin sections and fragments of cor
al aragonite are examined by transmitted light and scanning electron m
icroscopy. The geochemistry of these areas was investigated by ion mic
roprobe analysis. Microborings and centres of calcification (the origi
ns of crystal growth) contained significantly higher concentrations of
Ba and of Ba, Sr and Mg, respectively, than the surrounding crystal a
reas. Geochemical anomalies in microborings may be associated with an
amorphous lining observed in several of the boreholes. Centres of calc
ification are more porous than the surrounding material and may contai
n increased concentrations of the coral organic matrix which is enrich
ed in many metals compared to the skeleton. Geochemical anomalies in t
hese areas may significantly increase estimates of the Ba skeletal con
tent and may effectively overwrite palaeoenvironmental signals. Mg and
Sr anomalies would not significantly effect bulk determinations of th
ese metals.