In the Barito Basin of Borneo, there are extensive coal seams in the Miocene Warukin Formation. The net thickness of subbituminous C coal exceeds 100 m in the Tutupan mine. Three coal seams (from bottom to top: T110, T210, T300) were studied to explore the paleo-peat type and the factors controlling paleo-peat accumulation. The study is based on 93 coal and 7 non-coal samples, each representing a stratigraphic interval of 1 m. The samples were analyzed for ash yield, moisture, carbon and sulphur contents. All samples were analyzed using the Rock-Eval method and maceral analysis. Every second coal sample was used for detailed organic geochemical analysis.

The coal in the T110 (46 m thick) and T210 (24 m) seams are very low in ash and sulphur, suggesting peat formation in an ombrotrophic mire. Accumulation of seam T300 (24 m), which contains a higher amount of detrital minerals, is interpreted to have occurred in rheotrophic and ombrotrophic settings. n-Alkane and biomarker ratios indicate that accumulation of seam T110 began in a mire with a relatively high contribution of grassland vegetation. Apart from this early stage, angiosperms (including dipterocarps) dominated the forest swamp vegetation. The presence of gymnosperms, albeit at lesser extent, indicates that coal formation occurred in a kerapah (watershed) type peat. The geochemical data reveal a cyclic structure in the T110 and T210 seams, possibly controlled by climatic fluctuations. Five cycles were recognized in the T110 seam and three cycles in the T210 seam, each 6 to 13 m thick. Using accumulation rates of tropical peat in SE Asia and the compaction of low-rank coal, the duration of a single cycle was estimated to be 10.8 kyr (P10) to 61.1 kyr (P90), with a 50% probability that the true value is 22.7 kyr. A causal relationship between the climatic variability and the precession index (17–24 kyr) is suspected.

The maceral composition of the Tutupan coals is characterized by moderately high tissue preservation and low gelification, which is typical for tropical ombrotrophic mires. Huminite is the most important maceral group. Liptinite macerals (including resinite, cutinite, fluorinite and suberinite) are abundant, while inertinite macerals are rare. Funginite is one of the main inertinite macerals.

在婆罗洲的 Barito 盆地，中新世 Warukin 组有广泛的煤层。Tutupan 矿次烟煤净厚度超过 100 m。研究了三个煤层（自下而上：T110、T210、T300），探索古泥炭类型及控制古泥炭成藏的因素。该研究基于 93 个煤和 7 个非煤样品，每个样品代表 1 m 的地层间隔。分析样品的灰分产量、水分、碳和硫含量。使用 Rock-Eval 方法和局部分析对所有样品进行分析。每隔一个煤样就被用于详细的有机地球化学分析。

T110（46 m 厚）和 T210（24 m）煤层中的煤灰分和硫含量非常低，这表明泥炭层是在营养性沼泽中形成的。T300 煤层 (24 m) 的堆积，其中含有较多的碎屑矿物，被解释为发生在流变和 ombrotrophic 环境中。n-烷烃和生物标志物的比率表明，T110 煤层的积累始于具有较高草地植被贡献的泥潭。除了这个早期阶段，被子植物（包括龙脑香）在森林沼泽植被中占主导地位。裸子植物的存在，尽管程度较小，表明煤的形成发生在 kerapah（分水岭）型泥炭中。地球化学数据揭示了 T110 和 T210 煤层的循环结构，可能受气候波动的控制。T110 煤层有 5 个旋回，T210 煤层有 3 个旋回，每个旋回厚度为 6 至 13 m。使用东南亚热带泥炭的堆积速率和低阶煤的压实度，估计单个循环的持续时间为 10.8 kyr (P10) 至 61.1 kyr (P90)，真实值为 50% 的概率为22.7 基尔。

Tutupan 煤的主要成分的特点是组织保存程度适中，凝胶化程度低，这是热带营养沼泽的典型特征。腐殖质是最重要的矿物组。Liptinite macerals (包括resinite、cutinite、fluorinite和suberinite)是丰富的，而inertinite macerals是罕见的。Funginite 是主要的惰性物质之一。