Petrography, Geochemistry and Petrogensis of Pleistocene Basaltic Flow from Northwest Atarous Area, Central Jordan
Fifteen basaltic rock samples were collected from central Jordan at the Atarous
volcanism basaltic flow area. The samples cover about 8 km2 from the
Atarous Basalt flow (AB). The AB flow was introduced in the Miocene to
Pleistocene periods. The samples analyze major and trace elements by using
XRF. Petrography, Geochemistry and Petrogensis have investigation to carried
out for the AB. The petrography analyses of the AB rocks show they are
composed of plagioclase (labradorite and bytownite), pyroxene (augite), and
olivine (forsterite); accessory minerals include apatite and secondary minerals
magnetite, ilmenite, spinel and iddingsite. The AB is classified within alkaline to
sub-alkaline and tholeiitic to Calc-Alkaline basalt. The Mg# range between
0.39 and 0.49 of basalt samples exhibits different degrees of fractionation with
a low degree of melting < 15% as indicated from the varying concentration of
incompatible trace elements Ba, Rb, Sr. Trace elements of primary magna
show low variable abundances of compatible and incompatible elements,
which reflecs a homogenous source. Geochemical parameters such as Mg#
and high Ti contents indicate that the corresponding magmas are of primary
origin. The tectonic setting of AB is explained by using discrimination diagrams,
Ti-Zr-Sr and Nb-Zr-Y and Ti-Zr-Y, the AB plotted within the plate
basalt, alkali basalt and Calk alkaline basalt field, respectively. The spider diagram
shows the samples AB enrichment of the Ba, K, Nb and Ce, depletion of
Nb and Y. The AB exhibited positive Nb, Ce and Ti anomalies, and negative
anomalies of Ba, Sr, and P. It is attributed to the fractionation of feldspar for
Ba and Sr and apatite for P depletion. The spider diagram showed a positive
Nb peak, which conforms to the tertiary and to recent continental alkali basalt
provinces and indicates that the AB is the product of lithosphere from
upwelling asthenosphere mantle.