The Lignite Beds of Tabriz are among the Neogene formations in the northwest region of Iran that were formed as individual basins in the margin of the Tabriz fault and the suburbs of Tabriz City during the Late Miocene. These beds have many similarities in terms of facies and lithology. In this study, two stratigraphic sections of the main Lignite Beds unit, with a total thickness of 203 m, were measured and sampled. Fine- and medium-grained siliciclastics, limestones, lignite, tuff, and calcrete sedimentary facies were identified. The new fossils identified in this study include gastropods (Borysthenia naticina, Hydrobia sp., Lymnaea cf. longiscata, Planorbarius cf. comeus, Lymnaea cf. peregra and Zagrabica sp.) and diatoms (Coscinodiscus cf. gigas). The living environment of all fossils identified in this study was investigated. The sedimentary environment of the Lignite Beds is lacustrine and includes subenvironments of deep lake (offshore), shallow beach (shoreface), marginal swamps, prodelta, and interdelta distributary channels. The presence of fresh and brackish water forms along with euryhaline-marine taxa indicates that it was a lake basin near the Paratethys Sea. In a tectonic context, the Lignite Beds of the Tabriz sedimentary basin and its related basins were formed in pull-apart basins along the strike-slip North Tabriz Fault (NTF). The Lignite Beds were progressively transported along the NTF and migrated into the restraining bend of the NTF.

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