Diamondiferous kimberlites are closely associated with stable Archean cratons, whereas diamond=bearing olivine lamproites are intruded into adjacent mobile belts. However, a newly discovered diamond field in NW Syria differs from both these settings. Clusters of rift-induced diamond-bearing eruptives into Jurassic dolomites of the western block of the Syria Graben are dated at 110-115 m.y., similar in age to the Mesozoic reuptive event in southern, west and east Africa, brazil, North America, and Siberia. Diamond host rocks in syria are neither kimberlites nor lamproites, but some approach the composition of essexite or basanite. Samples of unweathered drill cores are exotic polymict volcanoclastic breccias with serpeintine, glass and mineral fragments set in a carbonate matrix. Upper mantle-derived xenoliths are garnet lherzolite, dunite and discrete megacrysts of ilmenite, diopside, and garnet. Crustal xenoliths are garnet granulites, gabbros, and amphibolites. The N-S Syria Graben is an extension of the East African, Ethiopian, Afar, Red Sea and Dead Sea Rift systems, parts of which have been continuously active since at least the Jurassic. Rift-induced alkali magmatic sampling of paleo-kimberlites or lamproites in pre-existing conduits is one possible model for the generation of the non-trrditional diamond host rocks in the Arabian Plate of NW Syria. This unusual tectonic setting and the exotic nature of the hybrid diamond host rocks is the focus of this proposal. Bulk and mineral chemical and stable isotope techniques will be applied to test the hybridization model, or alternatively to establish that these are indeed primary upper mantle melt products from within the diamond stability field.
