Depositional Model of the Sehkaniyan Formation (Early Jurassic) in Selected Sections from Northeastern Iraq

Enas Y.  Alzebari; Mohamed Ahmed Mohamed Alhaj

Article Details

Depositional Model of the Sehkaniyan Formation (Early Jurassic) in Selected Sections from Northeastern Iraq

Authors:

Enas Y. Alzebari | Mohamed Ahmed Mohamed Alhaj

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.58 Issue 2E, pp.190-209

Document Type:

Article

Publication Date:

11/2025

Document Language:

English

Document ID (Org No.):

2001836927

pISSN:

2663-8754

Keywords:

Abstract:

 The succession of the Sehkaniyan Formation (Toarcian) was studied in two surface sections from northeastern Iraq. The first section is located in the Sulaymaniyah Governorate, while the second is in the Erbil Governorate, Kurdistan Region of Iraq. The distance between the two sections is 86 km. The formation was divided in the field into three lithostratigraphic units. Petrographic study revealed that mollusks (gastropods and pelecypods), ostracods, echinoderms, and benthic foraminifera, as well as intra-clasts and fecal pellets, are the most important grain components within a micritic matrix. The studied rocks were also affected by several diagenetic processes, such as dolomitization, recrystallization, cementation, dedolomitization, and silicification. The facies analysis identified five lithofacies: the limestone lithofacies, dolomitic limestone lithofacies, marly limestone lithofacies, brecciated dolomitic limestone lithofacies, and laminated stromatolite lithofacies; and four main microfacies, which were subdivided into nine submicrofacies: non-fossiliferous lime mudstone submicrofacies, fossiliferous lime mudstone submicrofacies, intraclastic lime wackestone submicrofacies, ostracod lime wackestone submicrofacies, bioclast lime wackestone submicrofacies, benthic foraminiferal lime wackestone submicrofacies, bioclast lime packstone submicrofacies, Peloidal Lime packstone Submicrofacies and bindstone lime submicrofacies. These facies reflect the deposition of the formation within a ramp setting, where two parts of the ramp were distinguished: the inner ramp, which represents the peritidal and lagoon environments, and the middle ramp, which is represented by the shoal and open marine environments. The suggested ramp model is consistent with the paleogeographic situation of the study area during the Early Jurassic, when shallow and restricted basins dominated by carbonate sediments prevailed.

Article Details

Depositional Model of the Sehkaniyan Formation (Early Jurassic) in Selected Sections from Northeastern Iraq

Authors:

Enas Y. Alzebari | Mohamed Ahmed Mohamed Alhaj

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.58 Issue 2E, pp.190-209

Document Type:

Article

Publication Date:

11/2025

Document Language:

English

Document ID (Org No.):

2001836927

pISSN:

2663-8754

Sehkaniyan

Early Jurassic

Lithofacies

Depositional model

Ramp

Issues

Article Details

Depositional Model of the Sehkaniyan Formation (Early Jurassic) in Selected Sections from Northeastern Iraq

Authors: Enas Y. Alzebari | Mohamed Ahmed Mohamed Alhaj

Publisher: Iraqi Geologists Union (Union of Iraqi Geologists)

Journal: The Iraqi Geological Journal Vol.58 Issue 2E, pp.190-209

Document Type: Article

Publication Date: 11/2025

Document Language: English

Document ID (Org No.): 2001836927

pISSN: 2663-8754

Sehkaniyan

Early Jurassic

Lithofacies

Depositional model

Ramp

Issues

Authors:

Enas Y. Alzebari | Mohamed Ahmed Mohamed Alhaj

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.58 Issue 2E, pp.190-209

Document Type:

Article

Publication Date:

11/2025

Document Language:

English

Document ID (Org No.):

2001836927

pISSN:

2663-8754