Tectonics and Geological Factors Controlling Cleat Development in the Barito Basin, Indonesia

Abstract

Abstract. Cleats are natural fractures within coal seams. This paper presents the results of regional cleat mapping and characterization in relation to coalbed methane (CBM) exploration and development in the Barito Basin, South Kalimantan, Indonesia involving two major coal layers, namely the Late Eocene Tanjung Formation and Early to Middle Miocene Warukin Formation with thicknesses ranging from 2 to 50 m. The coal is classified as lignite to subbituminous with calorific values ranging from 6000-8000 Cal/gr with ash content 0.68-17.42%. We applied two methods of cleat measurement, i.e. scanline and window sampling using a 100 x 100 cm grid. More than 20,000 cleats were measured from 65 scanline and 37 window sampling locations. The results revealed that face and butt cleats are predominantly oriented in the WNW-ESE and NNE-SSW directions, respectively. The results showed that cleat density increases related to structural position such as fold hinge and fault zone. The formation of the cleats may be influenced by several geological processes, where the cleats, which form during coalification, are superimposed by later processes such as fluid pressure and tectonic stresses and are seemingly also affected by the composition of the coal.

Organic geochemistry and petrography of Miocene ombrotrophic coals in the tropical Asem-Asem Basin (Kalimantan, Indonesia): Comparison to coeval subtropical coals in the Eastern Alps

“…The Tanjung Formation is overlain by shallow marine carbonates (Berai Formation) in the Asem-Asem Basin and the southern Barito Basin, and by fluvio-deltaic strata in the northern Barito Basin (Montalat Formation). The regressive Warukin Formation comprises marginal marine rocks with thin coal seams (typically <2 m; Sapiie and Rifiyanto, 2017) in its lower part (Barabai Member of Witts et al, 2012). The overlying Tapin Member (Witts et al, 2012) represents (south-)eastward prograding fluvio-deltaic sedimentary rocks with thick coal seams (Satyana et al, 1999;Witts et al, 2012).…”

“…In contrast, paleocurrent directions in the Asem-Asem Basin remained southeastward (Witts et al, 2014). Regression and basin inversion continued during deposition of the Dahor Formation (Witts et al, 2014), which consists mainly of alluvial to shallow marine reddish sandstone, polymict conglomerate, and siltstone (Sapiie and Rifiyanto, 2017). In the Asem-Asem Basin, coal seams are locally present in the lower part of the Dahor Formation (Arutmin, 2015).…”

Geology and the effect of compaction on base material disposal for the stability of coal disposal slopes in South Kalimantan, Indonesia

“…To the north, the Adang Flexure separates the Barito Basin from the Kutai Basin. Meanwhile, in the southern part, the boundary becomes a little more vague or appears to narrow towards the south to the Java Sea due to the absence of any observable appearance of structures or changes in lithofacies [6].…”

The Evolution of Geotech - 25 Years of Innovation

“…The Dahor Formation is tectonic mollase which was deposited in Barito Basin during the Early Miocene -Pleistocene Meratus Uplift (Satyana et. al., 1994in Sapiie & Rifiyanto, 2017Witts et. al., 2014).…”