Petrogenesis of Syenitic Magmatism in the Neo-Tethyan Zagros Suture Zone, Bulfat Complex, Kurdistan Region of NE Iraq: Insights into Tectonic Setting and Crustal Contamination

Fatima Fariq; Ahmed Aqrawi

Article Details

Petrogenesis of Syenitic Magmatism in the Neo-Tethyan Zagros Suture Zone, Bulfat Complex, Kurdistan Region of NE Iraq: Insights into Tectonic Setting and Crustal Contamination

Authors:

Fatima Fariq | Ahmed Aqrawi

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.59 Issue 1A, pp.71-97

Document Type:

Article

Publication Date:

1/2026

Document Language:

English

Document ID (Org No.):

2001836961

pISSN:

2663-8754

Keywords:

Abstract:

 Quartz syenite and nepheline syenite occur as massive bodies and dikes within the Bulfat complex in the Zagros Suture Zone, located in the Kurdistan region of northeastern Iraq, within the Penjween-Walash Subzone. This study examines the petrogenesis, geochemistry, and tectonic implications of these rocks. Petrographic analysis identified two intrusions: quartz syenite, which is silica-saturated, dominated by alkali feldspar, plagioclase, quartz, and garnet, with inequigranular, porphyritic, poikilitic, myrmekitic, and perthitic intergrowth textures. Nepheline syenite is silica-undersaturated, containing a significant amount of feldspar and feldspathoid, and mafic minerals such as amphibole, biotite, and aegirine-augite. It displays holocrystalline, inequigranular, poikilitic, and perthitic intergrowth textures, with alterations including cancrinite pseudomorphs, albitization, and sericitization. Whole-rock geochemistry classifies both as alkaline, characterized by higher SiO2 content in quartz syenite (64.2 to 68 wt.%) compared to nepheline syenite (57 to 59.3 wt.%), and elevated alkalis. Both show enrichment in Light Rare Earth Elements relative to Heavy Rare Earth Elements, but quartz syenite has a higher total ∑REE =106.6–383 ppm than nepheline syenite, 7.7–145.3 ppm. Negative Eu anomalies indicate plagioclase fractionation and limit crustal contamination, while two nepheline syenite samples show positive Eu anomalies, indicating plagioclase accumulation. High Rb/Sr ratios suggest that the crust was contaminated from pelitic and psammitic sources. Tectonic discriminant diagrams reveal a volcanic arc field, characterized by enrichment in large ion lithophile elements, reflecting mantle-derived magmas modified by subduction during the closure of the Neo-Tethys. The elevated Zr/Y ratio further supports a continental arc setting, reflecting partial melting and magmatic differentiation. This study highlights the roles of magmatic fractionation, crustal assimilation, and subduction-related processes in the formation of nepheline syenite and quartz syenite.

Article Details

Petrogenesis of Syenitic Magmatism in the Neo-Tethyan Zagros Suture Zone, Bulfat Complex, Kurdistan Region of NE Iraq: Insights into Tectonic Setting and Crustal Contamination

Authors:

Fatima Fariq | Ahmed Aqrawi

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.59 Issue 1A, pp.71-97

Document Type:

Article

Publication Date:

1/2026

Document Language:

English

Document ID (Org No.):

2001836961

pISSN:

2663-8754

Quartz syenite

Nepheline syenite

Bulfat complex

NE Iraq

Zagros Suture Zone

Continental arc

Issues

Article Details

Petrogenesis of Syenitic Magmatism in the Neo-Tethyan Zagros Suture Zone, Bulfat Complex, Kurdistan Region of NE Iraq: Insights into Tectonic Setting and Crustal Contamination

Authors: Fatima Fariq | Ahmed Aqrawi

Publisher: Iraqi Geologists Union (Union of Iraqi Geologists)

Journal: The Iraqi Geological Journal Vol.59 Issue 1A, pp.71-97

Document Type: Article

Publication Date: 1/2026

Document Language: English

Document ID (Org No.): 2001836961

pISSN: 2663-8754

Quartz syenite

Nepheline syenite

Bulfat complex

NE Iraq

Zagros Suture Zone

Continental arc

Issues

Authors:

Fatima Fariq | Ahmed Aqrawi

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.59 Issue 1A, pp.71-97

Document Type:

Article

Publication Date:

1/2026

Document Language:

English

Document ID (Org No.):

2001836961

pISSN:

2663-8754