Pearce Element Ratios Applied to Model Basic Rock Members of Phenai Mata Igneous Complex, Baroda District, Gujarat

Pearce element ratio (PER) diagrams were constructed for tholentic gabbro, alkali gabbro, dolerite and tholentic basalt of Phenal Mata Igneous complex (PMIC) Identifying potassium as a conserved element particularly during the course of basic magma(s) differentiation senes The observed variations among the tholentic basalts, dolentes, tholentic and alkali gabbros of PMIC on PER diagrams appear to be commonly controlled by the fractional crystallhzation of plagioclase, chnopyroxene and olivine in variable proportion Tholentic basalts and tholentic gabbros of PMIC could be derived from the same parental magma but proportion of crystallizing phases and even assemblages differ as reflected by their different slopes on PER diagrams The different intercepts with a common slope for tholentic gabbros and dolerites however strongly suggest their similarly involved differentiation mechanism but d1fferent parentage probably formed by slight contamiation of episodic tholentic magma by an alkaline one, which subsequently experienced the same differentation mechanism.