TITLE:
Contribution to the Petrography, Geochemistry, and Petrogenesis of Zarqa-Ma’in Pleistocene Alkali Olivine Basalt Flow of Central Jordan
AUTHORS:
Ibrahim Ahmad Ali Bany Yaseen
KEYWORDS:
Alkali-Olivine Basalt, Fractionation, Batch Melting, Zarqa-Ma’in, Jordan
JOURNAL NAME:
International Journal of Geosciences,
Vol.5 No.6,
May
23,
2014
ABSTRACT: 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.