Identification of Coarse-Grain (Lowe), Medium-Grain (Bouma), and Fine-Grain (Stow) Turbidite Sequences in the Amiran Formation (Lurestan Sedimentary Basin, Zagros, Iran)

Nasiri, Yaghub; Taghdisi Nikbakht, Samira; Sedaghatnia, Mostafa

doi:10.22084/psj.2026.31784.1484

Identification of Coarse-Grain (Lowe), Medium-Grain (Bouma), and Fine-Grain (Stow) Turbidite Sequences in the Amiran Formation (Lurestan Sedimentary Basin, Zagros, Iran)

Articles in Press

Authors

Yaghub Nasiri ¹

Samira Taghdisi Nikbakht ¹

Mostafa Sedaghatnia ²

¹ Assist. Prof., Department of Geology, Faculty of Sciences, University of Gonabad, Gonabad, Iran

² PhD Graduate, Central Laboratory Expert of Lorestan University, Khorramabad, Iran

10.22084/psj.2026.31784.1484

Abstract

In this research, four stratigraphic sections of the Amiran Flysch Formation in the Lorestan sedimentary basin were studied and examined. The thickness of the Amiran Formation in the Lorestan sedimentary basin reaches over 800 meters, and lithologically, it includes conglomerate, sandstone, shale, and, to a lesser extent, limestone. The Lowe sequence is observed in the coarse-grained facies of this formation, the Bouma sequence in the medium-grained facies, and the Stow sequence in the fine-grained facies, all indicating a submarine fan depositional environment. The Lowe sequence in these deposits includes six parts: R1 (traction bedload), R2 (traction sheet), R3 (traction sheet), S1 (traction bedload), S2 (traction sheet), and S3 (suspended load and water). The Bouma sequence includes five parts: A (sand and gravel with gradual grading), B (sand with parallel lamination), C (rippled sand), D (laminated silt), and E (mud with bioturbation at the top). The Stow sequence in these deposits includes nine parts: T0 (tabular planar lamination), T1 (contorted lamination), T2 (lenticular-wavy lamination), T3 (regular and thin lamination), T4 (indistinct lamination), T5 (grouped silt lamination), T6 (gradually graded silty-muddy lenses), T7 (mud with gradual grading), and T8 (mud with fine bioturbations). In these sequences, the S3 part of the Lowe sequence is equivalent to the A part of the Bouma sequence, and the C part of the Bouma sequence is equivalent to the T0 part of the Stow sequence.

Keywords

Amiran Formation

Turbidite

Lurestan

Zagros