Australian Journal of Earth Sciences (2001) 48, 515–530 INTRODUCTION: WHY ASSIGN GRANITES TO SUITES? According to the American Geological Institute glossary, the term suite can be used for ‘a set of apparently comag- matic igneous rocks’ (Bates & Jackson 1987). For at least 60 years the term has been applied to rocks resulting from the crystallisation of related magmas. Alling (1936) referred to the Pacific, Atlantic and Mediterranean suites to stress that the magmas giving rise to the volcanic rocks in each of those regions are different. During the last few decades the enormous increase in field, petrographic and chemical data on granites has necessitated subdivision of these abundant data into groups to produce systematic trends in otherwise scattered data. In our usage, a suite is a group of igneous rocks (granitic rocks are mainly discussed here) with common textural, mineralogical and compositional characteristics, or a sequence of such characteristics, based initially on field, then on petrographic, and finally on compositional data. Granites, which might be grouped into suites except for small compositional differences that preclude such a precise grouping, are placed in supersuites. Here we define simple suites as those in which the abun- dances of elements are strongly correlated (linear varia- tions), and in which the chemical variations within different mappable units commonly overlap and supple- ment each other. Intricate suites are those in which the variations of at least some elements are not linearly related and such suites vary in their complexity.We refer to examples of different types of suites and supersuites mainly from the Lachlan Fold Belt, but also from the New Granite suites and supersuites of eastern Australia A. J. R. WHITE, 1 * C. M. ALLEN, 2 S. D. BEAMS, 3 P. F. CARR, 4 D. C. CHAMPION, 5 B. W. CHAPPELL, 6 D. WYBORN 7 AND L. A. I. WYBORN 5 1 Victorian Institute of Earth and Planetary Sciences, School of Earth Sciences, University of Melbourne, Vic. 3010, Australia. 2 Research School of Earth Sciences, Australian National University, ACT 0200, Australia. 3 Terra Search Pty Ltd, PO Box 981, Castletown, Qld 4812, Australia. 4 School of Geosciences, University of Wollongong, NSW 2522, Australia. 5 Australian Geological Survey Organisation, GPO Box 378, Canberra, ACT 2601, Australia. 6 ARC Key Centre for the Geochemistry and Metallogeny of the Continents (GEMOC), Department of Earth and Planetary Sciences, Macquarie University, NSW 2109, Australia. 7 ARC Key Centre for the Geochemistry and Metallogeny of the Continents (GEMOC), Department of Geology, Australian National University, ACT 0200, Australia. Separate granite plutons in southeastern Australia can commonly be grouped into suites on the basis of shared similarities in field, petrographic and compositional data. Granites in different plutons of the same suite share common properties or exhibit a sequence of such features. Rocks of the same suite are cogenetic, but the details of their genesis need not be known or agreed on, to group granite units in such a way. These rocks are cogenetic in the sense that they shared a similar petro- genesis and were derived from source materials of essentially the same composition, whereas differences between suites reflect analogous differences in their source rocks. The term suite is lithologic or lithodemic in a stratigraphic sense and is closely analogous to the lithostratigraphic term group. As such, the plutons within a suite need not be of the same age, and age is not a factor in recognising a suite. However, the fact that the petrogenesis of the components of a suite resulted in such similar products means that their ages are likely to be similar. Granite plutons that share many similar features, but which also show distinct differences and which may be assigned to more than one suite, may be grouped into supersuites. The allocation of granites to suites is fundamental to understanding their petrogenesis. Suites vary in the complexity of their compositional variation. Simple suites show variations in element abundances that are highly correlated and the dispersion of composition within such suites is considered to result from varying degrees of fractionation of entrained restite from a melt. Intricate suites vary in composition in more complex ways and their variation is considered to be a consequence of processes such as fractional crystallisation. Any mineralisation is generally associated with intricate suites, and the occurrence of mineralisation and its precise character is generally specific to particular suites. KEY WORDS: granite, Lachlan Fold Belt, lithodeme, mineralisation, petrogenesis, pluton, source rocks, suite, supersuite. *Corresponding author: allanite@earthsci.unimelb.edu.au