Petrology and Origin of Ultramfic Xenoliths from North Eastern Jordan Volcanoes

Abstract

The distribution of major, minor and trace elements in the Cenozoic alkali basalt from north-eastern Jordan indicates a homogeneous lava flow from a mantle source. These basaltic rocks contain abundant upper mantle xenoliths (spinal lherzolite, harzburgile and olivine- websterite). Theses xenoliths contain olivine, orthopyroxne, clinoporoxene and a few amounts of spinal. Their mineral assemblages, chemistry, texture and major elements abundances indicate they were derived and equilibrated under upper mantle conditions within temperature range for 970-1090°C. Pressure estimates based on the spinal lherzolite stability field restrict the xenoliths source depth to around 65 km. The concentrations of incompatible trace elements (Ba, Rb and Sr.) imply a derivation from ultramafic predictive source from the upper mantle with low degree of melting (<20%). Low concentration of Lithium and Rubidium in the basalt is used as an argument against the contamination of the basaltic magma during its journey to the surface

Contribution to the Petrography, Geochemistry, and Petrogenesis of Zarqa-Ma’in Pleistocene Alkali Olivine Basalt Flow of Central Jordan

“…The low content of SiO 2 (40.83 -47.55 ppm) and high content of MgO (6.3 -11.7 wt%) and total FeO (7.36 -15.42 wt%) indicated the natural fractionation of the MB. Furthermore, the high concentration of Cr (115 -324 ppm) is consistent with the earlier findings reported for primary magma (e.g., 257.6 ppm [5], 313.6 ppm [14], 241 ppm [31], and 125.3 ppm [43]). The high Mg≠ (average of 0.52) observed for MB in the present study is similar to that reported earlier for rocks affected by fractionation or accumulation of plagioclase, clinopyroxene, orthopyroxene, and olivine [35].…”

Petrography, Geochemistry and Petrogensis of Basal Flow from Ar-Rabba Area, Central Jordan

“…The high concentration of Cr (18 to 385 ppm) with average 246.87 ppm is consistent with findings reported for primary magma |(e.g., 241 ppm [30], 257.6 ppm [11], 313.6 ppm [19], 125.3 ppm [46], 95 ppm [42]. The high Mg# (average 55.66) for RB is similar to that reported for rock affected by fractionation or accumulation of clinopyroxene, orthopyroxene, and olivine and plagioclase [34].…”

Characterization of Mineralogy, Petrography, Geochemistry and Petrogensis of Basaltic Outcrops in Jurf Ed Darawish Area, Central Jordan

“…The ternary diagrams for Ti-Zr-Sr and Ti-Zr-Y diagrams (Figure 7(b) and Figure 7(c)) after [32], shows all the JDB Rock samples plotted within the calcalkaline basalt field. The MgO-FeO(tot)-Al 2 O 3 diagram after [38], shows the JDB rock samples were plotted within continental basaltic field (Figure 7(d) [39]. The high Mg# (average 46) for JDB is similar to that reported for rock affected by fractionation or accumulation of clinopyroxene, orthopyroxene, as well as olivine and plagioclase [40].…”