- journal_title：The Canadian Mineralogist
- Contributor：Olga García-Moreno ; L. Guillermo Corretgé ; Antonio Castro
- Publisher：Mineralogical Association of Canada
- Date：2007-
- Format：text/html
- Language：en
- Identifier：10.2113/gscanmin.45.1.71
- journal_abbrev：Can Mineral
- issn：0008-4476
- volume：45
- issue：1
- firstpage：71
- section：Articles
Cordierite monzogranites of the Hercynian Iberian massif have geochemical and textural characteristics that are different from those of the two main recognized families of granitic rocks in the Iberian massif: the peraluminous leucogranites, generally associated with high-grade anatectic zones, and the granodiorites, usually peraluminous and mostly emplaced later. The features of the cordierite monzogranites indicate links to these families. They contain a cordierite-group mineral as the main ferromagnesian phase, have alkali feldspar megacrysts, and commonly show complexly zoned plagioclase. The existence of this intermediate and transitional group of granites constitutes a major problem in granite petrogenesis. A crustal origin has been inferred from previous studies on their genesis; however, a more complex process is invoked to explain their geochemical features, as the major-element composition of these monzogranites does not match the composition of melts obtained experimentally from pelitic metasediments. In addition, the isotopic signatures (Sr–Nd) of these granites do not match those of any known source in the crust where these granites are emplaced. The presence of cordierite as the most characteristic ferromagnesian phase has also to be explained. In this paper, we propose a two-component process of assimilation to explain the origin of this type of granite. After the genesis of peraluminous melts related to an anatectic process, a two-component process of assimilation, involving both country rocks and more mafic mantle-derived material, is proposed in a general model that is based on geochemistry, textures and field relations of cordierite monzogranites, together with isotopic and experimental constraints.