The Camagüey province of central Cuba plays host to four granitoid formations of a Cretaceous volcanic arc. One of these four, the Sienitic Formation of the Sibanicú- Las Tunas massif, is host to an alkaline syenite. The main facies consists of a potassic, coarse-grained biotite-hornblende syenite with minerals including orthoclase (75-80%) oligoclase (8-10%), hornblende and biotite (7-15%), and accessory magnetite, sphene, apatite, zircon, baddeleyite, and molybdenite (2-3%). Arfvedsonite is found as a rim around primary hornblende, and euhedral baddeleyite is believed to have formed subsequent to zircon suggesting a late stage subsaturation of silica in the magma. Baddeleyite analysis and whole rock major element data can be found in González et al. (2013).