Boletín de la Sociedad Geológica Mexicana / 73 (1) / A140920/ 2021 / 1 Sedimentary environment and provenance of sandstones from the Qadir member in the Nayband Formation, Tabas block, east-central Iran Ambiente sedimentario y procedencia de las areniscas del miembro Qadir de la Formación Nayband, bloque de Tabas, centro-este de Irán 1 1,* 1 1 Ehsan Zamaniyan , Mohammad Khanehbad , Reza Moussavi-Harami ,Asadollah Mahboubi ABSTRACT 1 Department of Geology, Faculty of Sci- ABSTRACT RESUMEN ence, Ferdowsi University of Mashhad, Azadi Square, Mashhad, Iran. Qadir Member of Nayband Formation, El miembro Qadir de la Formación Nayband, * Corresponding author: (M. Khanehbad) located in East of Central Iran, has ubicada en el este del centro de Irán, se ha [email protected] developed to a great extent. Investigation desarrollado en gran medida. La investigación of the lithofacies and sedimentary de la litofacies y el medio sedimentario resultó environment, resulted in identification en la identificación de los depósitos deltaicos of the deltaic and marine deposits. y marinos. Basado en evidencia de campo y Based on field evidence and facies fea- características de facies, Qadir Member consta tures, Qadir Member consists of two de dos litofacies, incluidas facies de carbonato lithofacies, including carbonate and y siliciclástico. Se identificó que las facies siliciclastic facies. The siliciclastic facies siliciclásticas tenían cuatro facies de arenisca, were identified as having four sandstone incluidas Sr, Sh, Sp, St, tres litofacies de grano facies including Sr, Sh, Sp, St, three fine- fino, incluidas FI, Fm, Fl (Sr) / Sr (FI) y una grained lithofacies, including FI, Fm, Fl facies de carbón. Además, con respecto al campo, (Sr) / Sr (FI) and one coal facies. Also, los estudios de laboratorio y la identificación de regarding the field, laboratory studies, litofacies, se identificaron la llanura costera, and identification of lithofacies, the deltaica (incluida la llanura deltaica, frente coastal plain, deltaic (including deltaic deltaico proximal, frente delta distal y prodelta) plain, proximal delta front, distal delta y ambientes marinos abiertos para el Miembro front, and prodelta) and open marine Qadir que se encuentra bajo el impacto. de las environments were identified for Qadir corrientes de marea. El índice de meteorización Member which is is under the impact química (71%) indicó condiciones semiáridas a of tidal currents. The chemical weath- semihúmedas y el trazado de los datos geoquími- How to cite this article: ering index (71%) indicated semi-arid cos mostró la procedencia del reciclaje y el mar- Zamaniyan, E., Khanehbad, M., Moussavi- to semi-humid conditions and plotting gen continental activo y, debido al índice químico Harami, R., Mahboubi, A., 2021, Sedimentary the geochemical data showed the prov- de alteración, la tasa de meteorización resultó ser environment and provenance of sandstones enance of re-cycling and active conti- bastante media. en lo alto. Los diagramas geo- from the Qadir member in the Nayband nental margin and because of Chemical químicos también mostraron una fuente probable Formation, Tabas block, east-central Iran: Index of Alteration, the weathering rate de rocas ígneas y sedimentarias intermedias. Las Boletín de la Sociedad Geológica Mexicana, was found to be rather medium to high. condiciones del margen continental activo para 73 (1), A140920. http://dx.doi.org/10.18268/ The geochemical diagrams also showed este depósito podrían sugerir la subducción de BSGM2021v73n1a140920 a probable source of the intermediate Neotethys bajo la placa de Irán y la actividad igneous and sedimentary rocks. The volcánica al final del Triásico, que coincidió active continental margin conditions for con la orogenia cimeria temprana en Alborz y el Manuscript received: March 16,2020 this deposit could suggest the Neotethys microcontinente iraní centro-este. Corrected manuscript received: August 25, 2020 Manuscript accepted: September 14, 2020 subduction under Iran’s plate and volca- nic activity at the end of Triassic, which Palabras clave: Formación coincided with the early Cimmerian Nayband, Triásico, Bloque Peer Reviewing under the responsibility of orogeny in Alborz and Central East Tabas, Ambiente sedimentario, Universidad Nacional Autónoma de México. Iranian Microcontinent. Procedencia. This is an open access article under the CC BY-NC-SA Keywords: Nayband Formation, license(https://creativecommons.org/licenses/by-nc-sa/4.0/) Triassic, Tabas Block, Sedimentary environment, Provenance. Sedimentary environment and provenance of sandstones from the Qadir member in Nayband Formation http://dx.doi.org/10.18268/BSGM2021v73n1a140920 2 / Boletín de la Sociedad Geológica Mexicana // 7373 (1)(1) // A140920/A140920 / 2021 2021 1. Introduction facies analyses, investigation of provenance (tec- tonic setting, source region, and paleoweathering Examination of sedimentary facies is one of the of the original region) has always been the center most important tools in identifying sedimentary of attention. Nowadays, the geochemical studies and the implementation of discriminant diagrams INTRODUCTION / GEOLOGICAL SETTING environments and interpreting sedimentation pro- cesses in different areas. Investigation of sedimen- have been used as an effective tool to identify the tary facies is a very good basis for sedimentology siliciclastic rocks. This study aims to investigate studies to interpret global sea-level changes (Geel, and interpret the sedimentary environment and 2000). One of the most important ways to identify provenance of siliciclastic deposits of the Qadir and determine facies and interpret the sedimentary Member of the Nayband Formation in the east of environment is the use of lithology data including Central Iran (Tabas Block) through the field stud- field studies, petrography, or geochemical analyses ies, petrography and modal analysis along with (Flugel, 2010). Accordingly, facies analysis iden- geochemical methods. Our results can be used for tifies sedimentological features that include grain reconstruction of the paleogeography of eastern size, texture, and sedimentary structures, while part of Central Iran during Late Triassic. facies associations characterize the alteration of sedimentation processes in the sedimentary envi- ronment (Aboumaria et al., 2009). Since lithofa- 2. Geological Setting cies are controlled and formed by sedimentation processes in sedimentary environments, the study The study area is located in the central part of and identification of lithofacies are a great help in Central East Iranian Microcontinent (CEIM). the interpretation of syn-sedimentation processes Tabas Basin is an intra-continental depression (Catuneanu, 2003). and a part of the CEIM witch has experienced Also, the relation of tectonic setting, prove- a complex structural history (Aghanabati, 2006). nance, and composition of siliciclastic rocks has The tectonic movements of Early Cimmerian at been investigated by many researchers (Dickin- the end of the Middle to Late Triassic time played son and Suczek, 1979; Bhatia and Crook, 1986; an important role in forming Iran’s geology in the Quanren et al., 2002; Tijani et al., 2010; Ozkan and Late Triassic and Jurassic. At this time, the shallow Ayaz‐Bozdag, 2011; Mishra and Sen, 2012; Zhang coastal-continental basins, in addition to siliciclas- et al., 2014; Fleming et al., 2016, Fathy et al., 2018; tic rocks, caused the coal-bearing sequences to be Sabbagh Bajestani et al., 2018; Iqbal et al., 2019; formed between the two tectonic occurrences of Zamaniyan et al., 2019), because the interpreta- Early Cimmerian to Middle Cimmerian orogeny tion of provenance could be used to identify the (Wilmsen et al., 2009a). After the occurrence of pre-sedimentary history and reconstruction as well Early Cimmerian orogeny, because of the sea as interpretation of initial erosion of the source level rise, Nayband Formation (Late Triassic) with rock up to the final deposition and burial history of the thickness of 3000 m was deposited in Cen- rocks (Weltje, 2002; Weltje and Von Eynatten, 2004; tral Iran’s sedimentary structural zone and the Khanehbad et al., 2012a, 2012b). Clastic modal type section has been measured and introduced analysis of sandstones is employed to identify the in south of the Nayband Mountain (the West of tectonic settings and the relationships of sandstone Nayband village; Aghanabati, 2006). The Late compositions and their provenance (Dickinson Triassic (Norian-Rhaetian) Nayband Formation is and Suczek, 1979; Dickinson et al., 1983; Dick- distributed over a large area in central and eastern inson, 1985; Critelli, 1993). The tectonic setting part of Iran (Seyed-Emami, 2003). Five members is considered to be one of the major controlling have been recognized at the type section of the factors for sedimentary compositions (Dickinson, formation (Bronifman et al., 1971; Kluyver et al., 1985). Accordingly, in addition to petrography and 1983; Aghanabati, 2006), which are from the Sedimentary environment and provenance of sandstones from the Qadir member in Nayband Formation http://dx.doi.org/10.18268/BSGM2021v73n1a140920 Boletín de la Sociedad Geológica Mexicana / 73 (1) / A140920/ 2021 / 3 base to the top: 1- Gelkan Member, 2- Bidestan fault in the west. The Qadir Member of the Nay- Member, 3- Howz-e-Sheikh Member, 4- Howz- band Formation in Parvadeh Coal Mine section e-Khan Member, and 5- Qadir Member. The (33° 00’ 21”N and 56° 48’ 40”E) is located about Nayband