Karst imaging of Mangkalihat in East Kalimantan; insight from Landsat OLI 8, DEMNAS and field investigation

Abstract

Karst is one of the typical of landscape which is formed by soluble rock and mineral formation such as limestones, dolomites, gypsum, anhydrites and others types that have the same chacateristic. Based on Permen ESDM 17/2012, Karst Landform Area has two main function; conservation and development area. Mangkalihat Karst has some critical issues both on conservation and sustainable utilisation of its resources. We aim to delineate karst landform and other limestones formation in the area. Using DEMNAS-based combined with the multispectral imagery from Landsat OLI 8, we were able to delineate the karst area according to visual interpretation on karst morphology. Mangkalihat Karst presents as half-circular morphology consists of Tendehantu Hills in the west and Mangkalihat Hills in the east. The stratification of limestones formation has been clearly visible on image structured parallel strike with the arc. The slope is very steep (more than 45%) and it is densely vegetated areas. To the north, karst morphology formed undulated karst hills as slope average ranging from very steep to moderate. Scattered conical hills were identified as a result of surface karstification. However, drainage pattern had not clearly formed in karst landscape, they were formed subsurface. Tendehantu Formation (Tmt) is the main rock formation in the Mangkalihat Karst. Field investigation indicated that Tendehantu Formation (Tmt) is composed by coral limestones, white to light yellowish in color, well bedded and depsited during Middle Miocene in shallow marine (neritic zone). Caves and subsurface rivers had been identified in the area as a manifestation of endogenic and exogenic karst. The result can be approched for resource sustainability in Mangkalihat Karst Area.