Balochistan Basin

The Balochistan Basin shows distinct segments; c.g. the Arc Trench system of Chagai
including the Chagai Eruptive Zone, where a volcanic arc developed with chain of volcanoes, in the
Koh-i-Sultan, Koh-i-Taftan and Koh-i-Bazman. Tentatively included in it is the Raskoh Range with
Cretaceous volcanic flows, pyroclastic rocks, some sedimentary rocks with granodiorites. This is
called the Chagai-Raskoh Province.
The above-mentioned Chagai-Raskoh Province is suggestive of an Andean type arc-trench
system developed on the southern margin of the Iran-Afghanistan micro-continental plates. In this
area, rapid northward subduction during Late Cretaceous gave rise to profuseandesitic volcanism on
the sub-parallel ENE trending arc massifs of the Chagai hills. Searle (1991) stated that the Raskoh
represents an uplifted slice of the basement rocks; comprising mantle derived material, Cretaceous
volcanic, post-Middle Eocene igneous intrusions, Paleocene sedimentary rocks and younger
conglomerates.
South of Raskoh, a crescent shaped plain of wind-blown sand is present including Hamun-cMashkhcl and Jaz Murian regional depressions noted by Farhoudi and Karig (1977) as Fore Arc
Basin. The region may have reservoirs of groundwater and hydrocarbon s(Searle, 1991).
Southern part of the Balochistan Basin, the Makran Province, has been interpreted as a large
sedimentary prism accreted during Cainozoic and has been compared with the modem arc-trench
gap (Farhoudi and Karig, 1977).About 200 km in the south, occurs the Gulf of Oman abyssal plain.
It is more than 3000 m deep and marks the location of the subduction of oceanic emst dipping
northwards(Searle,1991).
Balochistan Basin, in fact, represents Lut-Afghan micro-continent of the Asian Massand it is
not a part of the Indo-Pak plate. This basin is equated, with “Central Basin platform zone II' in the
regional tectonic framework by Shahand Quennell (1980).