In the eastern part of an ophiolitic complex in Sulabest area (in south east of Birjand) has exposed a metamorphic series including eclogite, blueschist, garnet bearing blueschist, amphibolite, epidote amphibolite, greenschist and micaschist. In addition to basaltic pillow lavas and cherts which have changed to eclogite and blueschist, were also metamorphosed most of gabbroic cumulate series to overlaying sheeted diabasic dykes. This metamorphism is within the limit of prehnite-actinolite(sub greenschist) to greenschist facieses. Presence of orbitoides microfossil within micritic limestones in ophiolitic complex, indicates Maastrichtian age of emplacement for ophiolitic complex. Thermobarometry results of eclogites showing that peak temperature of eclogites from Sulabest varies from 496 to 592°C and their peak pressures ranging from 22.0 to 26.4 Kbars. Epidote amphibolite retrograde metamorphism of these eclogites has been done in a temperature of 549 to 592°C and a pressure of 6.7 to 7.4 Kbars. Textural evidences and analyses results showing that, the second stage of metmorphism were taken place during ascending root of these rocks on to the surface. Coexisting of eclogites in studied area with blueschists, amphibolites and garnet amphibolites in the eastern part of an ophiolitic complex and combination of field observations and laboratory works, indicates that a subduction activity with a late Cretaceous age were responsible for the studied area and consequently for east of Iran, which were followed by an thrusting process during colliding of Afghan(Helmand) and Lut-Block plates.

The mafic and ultramafic igneous rocks of the ophiolitic complex in eastern Birjand) between Sulabest in southern part to north of Gazik in northern part) Have been studied.According to plot of data on diagrams and the result of mineralogy and geochemistry, gabbros and some peridotites belong to cummulate series of spreading sea floor magma (MORB) where some peridotites are of metamorphic (tectonics) types. Magmatic series of igneous rocks are tholeiitic. Trace elemental patterns similarities on spider diagrams also confirming the relations of these rocks to Mg-rich basaltic magma of MORB type. Geothermobarometry results of some rocks, based on different calibrations, show temperatures of 944LC for gabbros to 1294LC for peridotites. Temperature pressure calculations based on Holland and Powell thermocalc method, indicate, rocks crystallization conditions of 748LC and 17.46 Kb for gabbros to 1282LC and 24.7 -33.6Kb for peridotites. Most obtained temperatures, particularly the thermocalc ones, for crystallization conditions of these rocks from an initial Mg-rich magma, MORB type, in spreading sea floor seems to be reasonable.