Origin of high-potassium, talc-alkaline, I-type granitoids

Sources of post-orogenic calcalkaline magmas: The Arrochar and Garabal Hill–Glen Fyne complexes, Scotland

“…As pointed out by Roberts and Clemens (1993) magmas differentiating by crystal fractionation tend to produce rock series that plot on the SiO 2 -K 2 O diagram without crossing the boundaries between the different series, except where the magmas are initially transitional in chemistry. This is similar to the normal behaviour in the SiO 2 -MALI plot.…”

“…There has been debate about the origins of such magmas, in particular the high-K series. Proposed models involve processes such as partial melting of K-rich meta-andesites (e.g., Roberts and Clemens, 1993), reactive assimilation of metapelites by high-alumina basaltic magmas (e.g., Patiño Douce, 1995), simple mixing of felsic metasediment-derived and basaltic magmas (e.g., Davis and Hawkesworth, 1993) and melting of enriched mantle, accompanied by assimilation of crustal rocks and fractional crystallisation (e.g., Schaltegger and Corfu, 1992). Here, we present geochemical and isotope (Sr and Nd) data for a group of spatially and temporally associated mainly medium-to high-K plutonic rocks that range in composition from gabbros to granites.…”

Petrogenesis of the early Cretaceous Funiushan granites on the southern margin of the North China Craton: Implications for the Mesozoic geological evolution

“…(a) Roberts and Clemens, 1993;Sylvester, 1998;Zhao et al, 2013a). Xu et al (2009b) pointed out that the partial melting of crust can be triggered by thermal transmission between crust and mantle and relay on the underplating of mantle-derived magmas.…”

Lower Pliensbachian caldera volcanism in high-obliquity rift systems in the western North Patagonian Massif, Argentina

“…This feature is interpreted as evidence of subduction components. However, such a consideration is valid for those rocks in which the subduction environment can be set independently (Roberts and Clemens, 1993). …”