GEOCHEMICAL-PECULIARITIES OF THE ASTHENOS PHERE BENEATH THE ARABIAN PLATE - EVIDENCE FROM MANTLE XENOLITHS OF THE QUATERNARY TELL-DANUN VOLCANO (SYRIAN-JORDAN PLATEAU, SOUTHERN SYRIA)

Basaltic pyroclastics of the Tell-Danun volcano host three groups of d epth-derived inclusions: (1) spinel peridotites (dominantly spinel lhe rzolites), (2) green garnet-spinel and spinel websterites, and (3) hor nblendites and hornblende pyroxenites, megacrysts of kaersutite and il menite, and kaersutite intergrown with Al-Ti augite (''black series'') . All these are believed to be fragments of a subcontinental asthenosp heric mantle: the spinel peridotites originally made up its matrix, th e green websterites composed conduits for new-formed basaltic melts en route to the surface, and the ''black series'' rocks made up conduits by which high-density mantle fluids migrated. Garnet-clinopyroxene-or thopyroxene thermobarometry for the garnet-spinel websterites suggests that these rocks precipitated at depths of 24-30 lan or even at 35-54 lan which defines the depth to the top of the upper mantle beneath th e Arabian plate.