ORGIN OF LARGE TRAPEZOHETRA OF ANALCIME AND PUMPELLYITE AGHIDA AREA, CENTRAL IRAN

Large (Up to 3 cm in diameter), euhedral , cubic trapezohedra composed of single crystals analcime or aggregates of pumpellyite occur in three stratigphically adjacent tephriphonolite laves from the Aghda region. Large pumpellyite crystals are restricted to the lower flow and anallcime is restricted to the middle and upper flows. The trapezohedra contain concentrically arranged inclusions of plagioclase , pyroxene, titanomagnetite and apaite. In contrast to the albitised plagioclase inclusions in the pumpellyite trapezohedra, feldspar inculusions in anlcime are fresh with very minor normal zoning and range between An 56.0 and An 69.3 in composition.