Original Article Journal of Science and Applicative Technology vol. 5 (1), 2021, pp. 43-46 | 43 OGARA., Journal of Science and Applicative Technology vol. 5 (1), 2021, pp. 43-46 e-ISSN: 2581-0545 - https://journal.itera.ac.id/index.php/jsat/ Copyright © 2021 Journal of Science and Applicative Technology. Content from this work may be used under the terms of the Creative Commons Attribution-NonCommercial 4.0 International Licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by Journal of Science and Aplicative Technology (JSAT). Received 27th January 2021 Accepted 20th February 2021 Published 11th March 2021 Sedimentary Facies of Seblat Formation Semaka Districts, Lampung, Indonesia Evan Rosyadi Ogara *a a Geological Engineering Department of Institute Teknologi Sumatera * Corresponding E-mail: evan.ogaral@gl.itera.ac.id Abstract: Seblat Formation had been exposed in Sedayu village, Lampung. Stratigraphic measurements and detailed descriptions at several outcrops were performed on Seblat Formation. Seblat formation based on sedimentological study can be divided into two facies: classical turbidites and slump. Classical turbidites in the study area characterized by monotonous sandstone intercalated with mudstone and slump facies consist of mudstone and fine-grained sandstone with total thickness around 5 meters and the thickness of each layer from 3-13 centimeters. Based on two sedimentary facies, the mid fan (smooth- channeled) and the inner fan is proposed for Seblat Formation. Keywords: Seblat Formation, Sedayu village, Facies. Introduction This research aims to determine the facies of the Seblat Formation. The research area is located in Lampung. Lampung is located in the southern part of Sumatra island lies within the active tectonic plate of the India-Australia Plate and Eurasian Plate. There are two basins in Lampung, South Sumatra Basin as back-arc basin and Bengkulu Basin as a fore-arc basin. Seblat Formation is one of the formations in the Bengkulu Basin. Seblat Formation of Oligocene to Miocene age which is composed of interbedded claystone and sandstone, tuffaceous sandstone, shale, siltstone, and thin layer or nodules of limestone [1] Figure 1. Map of research area in Lampung province (unscaled) The research area's location is the administrative area of Tanggamus district, Semaka sub-district, Sedayu village (Fig.1). The outcrops at the west part of Tanggamus in Sedayu village will be used as the study area (Fig.2). Figure 2. Geology regional map of Kotaagung (modified from Amin et al., 1993) Bengkulu basin is located in the south-west part of Sumatera island. Two rock units occupy in Bengkulu area, namely Bengkulu zone and Barisan zone [2]. Barisan zone consist of Hulusimpang Formation, Bal Formation, Ranau Formation, Lakitan Formation and some intrusive rocks. Bengkulu zone consist of Seblat Formation, Lemau Formation, Simpangaur Open Access DOI: ϭϬϯϱϰϳϮũƐĂƚǀϱŝϭϰϬϭ