May Diamondiferous Associations Occur In The Central Negev (israel)?

Larson (1995) put forward a hypothesis on the extremely high development of diamond-bearing kimberlites in the Mid-Cretaceous period. In Israel, the Cretaceous magmatic activity is well known in the central Negev. The first microdiamond in Is- rael was found in the Negev (Flexer et al., 1988) in the Maastrichtian below the K/T boundary (the mentioned authors associated its origin with an extraterrestrial event). An integrated analysis of several geological and geophysical factors allowed to re- vealing for detailed investigations the Makhtesh Ramon area situated near the town of Mizpe-Ramon (central Negev). Within the area about 90 kg of samples for the subse- quent mineralogical-geochemical analyses have been selected. The following minerals of the anticipating diamondiferrous association in the selected samples were revealed: (first group) - chrome-diopside, orange garnet, bright-crimson pyrope, picroilmenite, black spinel, olivine, anatase and tourmaline. Chrome-diopside as an indicator mineral may be found only in the neighboring zone of basic pipe occurrence. Orange garnet, bright-crimson pyrope and tourmaline also are essential indicators of the presence of diamondiferrous association in the studied district. These minerals do not rolled that is additional evidence of the neighboring occurrence of the indigenous rocks. Data of electronic microscopy (Surkov et al., 2002) show that the grains of (1) picroilmenite and (2) pyrope contain, respectively: (1) cobalt, chrome, magnesium and nickel and (2) chrome, magnesium and aluminum. These data indicate that both picroilmenite and pyrope have the hyper-abyssal origin that also is an indicator of the possible occurring of diamondiferous pipes. Besides above mentioned minerals, list of determined min- erals in the samples (second group) includes: hexagonal quartz, feldspars, pyroxenes (black, green, dark-green, gray-green, brown-green), magnetite, hematite, ilmenite, galenite, pyrite, limonite, small magnetic spheres (quant. matter), mica, hydro-mica, chromite, leucoxene, zircon, rutile, secondary minerals of cuprum (green and blue), calcite, etc. These minerals (by their considering with the first group) are also indica- tors of the diamond-bearing of the studied area. It should be noted that the amount of

1 these minerals is extremely high: in 50 kg of investigated samples (selected from the loose deposits and conglomerate) till the present time (January 05, 2002) altogether al- most 1,800 grains (first group only) of the proposed diamondiferrous association have been detected. Thus, we could suggest that the Makhtesh Ramon area is perspective for discovering both basic diamondiferrous rocks (kimberlite and lamproite pipes) as well as diamond crystals in loose deposits.

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