Tectonic implications of the geochemical data from the Makran igneous rocks in Iran

Abstract

AbstractMakran is one of the largest accretionary prisms on Earth, formed by the closure of the Neotethys ocean which is now represented by its remnant, the Gulf of Oman. Tectonic evolution of the Makran island‐arc system is explored within the context of a north dipping subduction zone, with temporal variations in slab dip arrangement. In a Middle Jurassic–Early Paleocene steep slab dip arrangement, the Mesozoic magmatic arc and the Proto‐Jaz Murian depression, which was an intra‐arc extensional basin, were developed. This was associated with development of outer‐arc ophiolitic mélange and oceanward migration of the Bajgan–Durkan continental sliver, which is the continuation of the Sanandaj–Sirjan zone of the Zagros orogenic belt into the Makran region. In a Late Paleocene to Late Pliocene moderate to shallow slab dip arrangement, compression and tectonic inversion of the Proto‐Jaz Murian extensional basin into the Jaz Murian compressive basin was associated with the uplift of the southern part of the Jaz Murian Depression along the South Jaz Murian Fault, and emplacement of the Paleogene–Neogene magmatic arc, behind the Jaz Murian compressive basin. A shallow slab dip arrangement in the Quaternary led to the emplacement of a third magmatic arc inland, over the southern part of the Yazd–Tabas–Lut micro‐continental block. It is envisioned that the Makran island‐arc system will pass through similar tectonic events in the future, as the Zagros island‐arc system did in the past. However, a future remnant and/or residual basin similar to the present Gulf of Oman will continue to survive to the east.