Makran Cretaceous ophiolitic basalts (SE Iran)

What is it about?

In this paper, we present new major and trace element data as well as isotopic compositions of mafic volcanic blocks from the Makran ophiolitic mélange complex (OMC). These volcanic blocks are composed mainly of basalts with minor trachytes and occasionally with tuff layers. Zircons from these tuffs give U-Pb ages of 95 Ma. Makran basalts can be geochemically subdivided into 4 groups; normal to transitional MORB, enriched-MORB, Plume-type MORB and alkaline (-OIB-like) basalts. The OIB-like pillow lavas are represented by high values of Th/Tb (6.3-7.4) which are higher than other basalts (group 1= 0.3-0.8; groups 2=0.7-1.6; group 3=1.58-1.36). 143Nd/144 Nd(t) ratios for basalts range from 0.51247 to 0.51292, whereas 87Sr/86Sr(t) isotopic composition of the OMC lavas varies from 0.704433-0.709466. The Pb isotopic composition of the lavas are quite high, ranging from 15.49-15.66 for 207Pb/204Pb(t), 18.09-19.12 for 206Pb/204Pb(t) and 37.80-39.23 for 208Pb/204Pb(t). The chemistry of these rocks suggests that they were formed most likely in an oceanic setting with clear plume-ridge interaction.

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Why is it important?

this paper will help to find out about the geodynamic processes in Makran zone, SE Iran.

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