Geochemistry and tectonic setting of Gadani-Phuari Segment of Bela Ophiolites, Balochistan, Pakistan

Abstract EN

The volcanic rocks exposed at Gadani-Phuari area.

District Las-bela, Balochistan, mark part of the southernmost, onshore remnant of the Bela Ophiolites.

In Lasbela region, there are two prominent groups of Cretaceous igneous rocks.

The first are Bela ophiolitic rocks which are allochthonous in nature and are unrelated to the second group, i.e.

the Porali Intrusion which is equivalent to Deccan Trap and represent younger within-plate basalts (WPB).

The southern most exposure of Bela Ophiolites are present in small and scattered outcrops in Gadani-Phuan area west of Karachi.

Major and trace element analyses of 20 selected samples have been used for evaluating these rocks.

The variation of total .alkali with silica (TAS) of the volcanic rocks suggests that they are mostly alkaline basalts and trachy-basalts.

Whereas the trends of the other major and trace elements indicate that they are low K tho-leiites derived from a source similar to that of E-Type Mid Oceanic Ridge Basalt (MORB).

These ophiolitic rocks were emplaced onto the western margin of the Indian plate during Maastrichtian to Lower Eocene time.