Abstract: Evaluation of Mechanisms of Calcite Growth Inhibition and Morphology Control

Richard Lahann

Crystallographic considerations of the mechanics of ion incorporation into a crystal indicate that although certain mechanisms of Mg⁺² interaction with calcite may be responsible for inhibiting crystal growth, they may be inadequate to explain morphologic variation. Experimental evidence on the kinetics of calcite crystal growth indicates that dewatering of surface adsorbed Ca⁺² ions may be the rate-determining step in calcite growth, thus supporting, by analogy, the heat of hydration mechanism for Mg⁺² poisoning of calcite growth. Surface charge and colloid chemical considerations indicate that differential-charge development on crystal faces is responsible for morphologic variation in calcite. The surface-charge model for morphology cont ol successfully predicts the approximate Ca⁺²/CO₃^-2 ratio of water yielding equant calcite crystals and the morphology of aragonite crystals precipitated from seawater.

AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC