Granite suites: a problematic concept?

Abstract

In Australian stratigraphic nomenclature, the concept of granitic rock suites has been in formal use for over a decade. The basis for this suite classification of granitic rocks is inconsistent and, in eastern Australian usage, unsound on several levels. We also note that the approach used in Western Australia is different. Granitic intrusions are probably not truly amenable to any strict, comprehensive, lithostratigraphic classification. If these rocks are integrated into such a scheme, group- and supergroup-level units (i.e. formal suites and supersuites) should not be incorporated. For the present, mappable units should be recognised at the levels of formation and member. The use of granite suites and supersuites in formal stratigraphic hierarchies is not recommended. Instead, granitic bodies could be grouped into individual plutons, which may or may not form parts of larger batholiths.KEY POINTSThe suite-based classification of granitic bodies, as currently used in the Australian Stratigraphic Units Database, is based on unsound principles, and is not employed in a consistent manner.Granitic intrusive rocks probably cannot be grouped using lithostratigraphic principles that are consistent with either the local or international codes.Granitic bodies can be grouped into batholiths, plutons and members, but the names of these units should, for the moment, remain informal.