SOME COMMENTS ON INCLUSION RELATIONSHIPS

Evaluation of two commonly used microstructural criteria for determining the origin of inclusions, namely the existence of a host-inclusion orientation relationship and continuity between inclusions and matrix, using two specific examples of inclusions of tschermakite in actinolitic hornblende, shows that these criteria can be difficult to implement and if not applied carefully will give contradictory results. Consequently, it may be difficult to establish the origins of inclusions; petrographic studies should therefore clearly state the criteria used for interpretation of host-inclusion relationships and how these criteria were implemented.