Abstract
We surveyed the distribution and the chemical properties of peat in the Lahei district, northeast of Palangka Raya, Central Kalimantan, Indonesia. Along a transect line parallel to the Mangkutup River, peat was deposited only in a deep valley, which had a mineral surface ca. 10 m below the surrounding area. Along a transect line perpendicular to the river, the maximum thickness of the peat was 773 cm, 150 m from the river. The peat contained several clayey or carbonized layers, which suggested frequent flooding and drawdown during peat formation. We also studied the vertical profile of the chemical properties of the peat pore water. The properties changed at a depth of ca. 500 cm. pH and electrical conductivity were greater below this depth than above 500 cm. Major ions in the peat pore water reached maximum values below 500 cm. The redox potential reached minimum values at around 200 cm depth, remaining oxidative. These chemical properties suggest the presence of an under-ground water flow that supplies minerals and oxygen to the peat layer.
