Geology of the Laya area and its surroundings, Baturaja Barat sub-district, Ogan Komering Ulu Regency, South Sumatra Province

Vinsensia Purwaningtyas

Vinsensia Purwaningtyas Program Studi Teknik Geologi, Fakultas Teknologi Nasional Yogyakarta, Institut Teknologi Nasional Yogyakarta

Abstract

The research area is located in the Laya area and its surroundings, West Baturaja sub-district, Ogan Komering Ulu Regency, South Sumatra Province. Physiographically, the research area is included in the Physiography of the Low Hills and Undulating Plains Zone. In the Laya area and its surroundings, the research area is composed of rocks from Tertiary to Quaternary. The purpose of this study is to determine the geological conditions of the research area including stratigraphy, geomorphology, geological structure, geological history and aspects of the environmental geology in the research area. The method used in this study is surface geological mapping, this method includes observation, description and direct measurement in the field in the form of rock outcrop data, geological structure, geomorphology, sources and natural disasters. The Laya area and its surroundings are divided into 3 Geomorphological Units, namely the topographic geomorphological unit of hills and denudational slopes (D2), the geomorphological unit of denudational plains with gentle - undulating morphology (D5) and the river body unit (F1). The Laya area and its surroundings are composed of 5 rock units from old to young, namely the Kikim tuff unit, the Baturaja calcarenite unit, the Gumai carbonate sandstone unit, the Kasai sandstone unit, and sand. The geological structure that developed in this research area is controlled by tectonic activity which is characterized by the presence of fractures and folds in the form of Pusar anticlines, Pusar synclines, and Laya synclines. The Laya area and its surroundings have abundant natural resources and are used as plantations, baths, and mining. However, on the other hand, the research area has the potential for natural disasters, namely landslides or mass movements.

Keyword : Laya Area, Sedimentation, Geomorphological Units, Rock Units.

References

Dunham. Clasification of Carbonate Rock According Depositional Texture, AAPG. 1962.

Fleuty M. J. The Description of Folds. London: Proceedings of the Geologists Association. 1964; 75: p. 461-492.

Gafoer S, Amin Tc, Pardede R. Peta Geologi Lembar Baturaja, Sumatera, Sekala 1 : 250.000, Pusat Penelitian

dan Pengembangan Geologi, Bandung. 1993.

Grabau AW. On The Classification of Sedimentary Rocks. American Geologist. 1904; v.33, p.228-247.

Haldar SK, Tisljar J. Introduction to Mineralogy and Petrology. Elsevier Inc. United States of America. 2014.

Katili JA. Vulcanism and Plate Tectinics ini the Indonesian Island Arcs, Tectonophysics. 1974; 26: hal. 165-188.

Lobeck AK. Geomorphology an Introduction to the Study of Landscapes. New York: Mc. Graw-Hill Book

company, Inc. 1939.

Pulunggono A, Cameron, NR. Sumatran Microplates, Their Characteristics and Their Role in Evalution Of the

Central and South Sumatera Basin, Proceedings PIT XII IAGI, IAGI, Jakarta. 1984.

Pettijohn FJ. Sedimentary Rocks. Harper and Row Limited. New York. 1975.

Pulunnggono AH. Pre-Tertiary and Tertiary Fault System As a Frameework of the South Sumatera Basin; A

Study of SAR-MAPS, Proceeding Indonesian Petroleum Association (IPA 92-11.32). 1992.

Schimd R. Descriptive Nomenclature and Classification of Pyroclastic Deposits and Fragments:

Recommendations of the IUGS Subcommission on the Systematics of Igneous Rocks. Geology. 9(1),

-43.

Thornbury WD. Principles of geomorphology, John Wiley and Sons Inc., New York, U.S.A. 1954.

Thornbury WD. Principles of Geomorphology. Second Edition. John Wiley & Sons, Enschede. 1969.

Van Zuidam, R. A., & van Zuidam, F-I-Cancelado F. I. Terrain Analysis and Classification Using Aerial

Photographs. ITC, Netherlands. 1979.

Wentworth CK. A Scale of Grade and Class Terms for Clastic Sediments, Journal of Geology 30, 377-394. 1922.