Experimental hydrothermal studies on both synthetic and natural phases in a portion of the system MgO-Al2O3-SiO2-H2O reveal the polymorphic relationship between 7 Å sheet trioctahedral phases and true 14 Å-chlorites. Each polymorphic type allows continuous extensive isomorphous replacement of 2 Al3+ for Si4++Mg2+ terminating at the amesite composition. The equilibrium maximum stability temperature for the chlorites appears to reach a maximum at the composition of clinochlore (710° C. at 20,000 psi) and to decrease slightly (∼20° C.) towards both penninite and amesite. The nomenclature and relations among the various chlorites is discussed in the light of this information.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.