Makhtesh Ramon: A unique natural-resource complex of strategic, multi-component mineral raw materials in Southern Israel

An integrated analysis of regional geological and geophysical factors led to selecting the Makhtesh Ramon area (northern Negev, Israel) to search for diamondiferous associations.The most important regional factor is the Middle Cretaceous maximum in upper-mantle hot-spot development, which appears prominently in this area.Analysis of magnetic (paleomagnetic), self-potential, and ion-selective data unambiguously indicates the presence of some bodies possibly having kimberlite (lamproite) origin occurring at small depths (8-50 m) in the western Makhtesh Ramon.Repeated erosion in the area removed most of the sedimentary associations and significantly simplified mineral sampling and rock collection for geochemical and petrological analyses.Comprehensive mineralogical analyses enabled the detection of the following minerals-satellites of diamond associations: chrome-diopside, orange garnet, bright-crimson pyrope, picroilmenite, moissanite, corundum, black spinel, olivine, anatase, and tourmaline (including black samples).These minerals are not rolled or oxidized, providing additional evidence of their association with the indigenous rocks.Data from electron microscopy show that the grains of (1) picroilmenite and (2) pyrope contain, respectively: (1) cobalt, chrome, magnesium, and nickel and (2) chrome, magnesium, and aluminum.This indicates that both picroilmenite and pyrope have a hyper-abyssal origin, which also indicates the possible occurrence of diamondiferous pipes.Secondaryimportance satellite minerals include feldspars, pyroxenes, magnetite, hematite, ilmenite, galena, pyrite, limonite, mica, chromite, leucoxene, zircon, rutile, etc.These minerals (compared with the first group) also indicate diamond-bearing mineralization in the studied area.Small gold and silver plates, along with considerable traces of La, Ce, Th, Nb, and Ta (Rare earth elements), may also be associated with the nearest kimberlite rock occurrence.The total number of recognized microdiamonds exceeds 300; five diamonds (> 1 mm) were identified (the largest crystals are 1.2 and 1.35 mm).Thus, based on a set of geological-geophysical factors and the identification of the mentioned minerals, we estimate that the Makhtesh Ramon area is promising for discovering diamondiferous rocks (kimberlite or lamproite pipes) as well as diamond crystals in loose deposits.The discovered silver-, gold-, and REE-bearing signatures may be important on their own.