Petrography, Mineralogy, and Origin of the Syenite Pegmatitic Segregation Veins From La Peña Alkaline Complex, Mendoza, Argentina

The syenite pegmatitic segregation veins (SPSV) of the Early Miocene La Pena alkaline complex (LPC), Mendoza, Argentina, are emplaced in a malignite body. They occur as veins, parallel layers, and small elliptical bodies 1 to 6 cm wide and 0.2 to 1 m in length. The veins with a pegmatitic to micropegmatitic texture have a thin dark border composed of andradite, potassic-hastingsite, and dark micas and a thicker internal zone of poikilitic...