Contribution to the Petrography, Geochemistry, and Petrogenesis of Zarqa-Ma?in Pleistocene Alkali Olivine Basalt Flow of Central Jordan
The Zarqa-Ma?in basalt (MB) occurs near a plateau basalt (wadi fills) covering about 15 km2 of
Makawir, Ataruz, and Hammat um Hasana cone areas in central Jordan. The tectonic evolution
occurred through intraplate volcanism and erupted through fissure systems along the Dead Sea,
transforming the fault during Miocene to Pleistocene period. Three stages of eruption of MB have
been recorded during Pleistocene from 6 to 0.6 Ma. The petrographic analyses data show that the
MB rocks are composed of plagioclase, olivine, pyroxene, and magnetite, including secondary
minerals calcite, iddingsite, serpentine, and zeolite. Furthermore, the MB rocks have narrow
ranges of major and trace element concentrations, and are of under saturated silica type and belong
to sodic alkaline magma series. The geochemical characteristics of MB indicate that MB was
derived from a slightly fractionated magma as reflected by its high MgO (6.3 - 11.7 ppm) concentration
with Mg number from 0.41 to 0.61, low silica content (40.83 - 47.55 wt%), and high Cr and
Ni concentrations (115 - 475 and 105 - 553 ppm, respectively). This basalt exhibited low degree of
partial melting (10%) for garnet peridotite mantle source. The model mineral fractionation
showed that the MB could be fractionated to clinopyroxene, orthopyroxene, olivine, and plagioclase