SILICIC CUMULATES: FACT OR FICTION?

The existence of silicic cumulates in the mid- to upper-crust has become a topic of intense debate within the igneous petrology community. One of the primary approaches to determining the existence of these rock types in the geologic record has been focused on identifying geochemical indicators based on incompatible and/or compatible trace elements. In particular, recent studies have utilized large geochemical databases to determine the abundance of these rocks globally. However, without the spatial, petrological, and textural context of each rock our interpretation of this geochemical data can be significantly handicapped; therefore, leading to erroneous interpretations. Here we review a number of different geochemical and textural characteristics of silicic rocks from several case studies that integrate disparate datasets. We demonstrate that it is essential to evaluate geochemical data in the context of textures. Specifically, the nature of silicic cumulate textures are likely much more subtle than those found in mafic cumulates and, therefore, require careful and detailed quantitative analysis to definitively detect their existence.