Inorganic geochemistry of domed peat in Indonesia and its implication for the origin of mineral matter in coal

A drowned lycopsid forest above the Mahoning coal (Conemaugh Group, Upper Pennsylvanian) in eastern Ohio, U.S.A.

“…The relatively low ash yields, and low sulfur contents of the lower part of the main coal bench are consistent with a domed, ombrogenous interpretation; domed peats are characteristically low in ash (< 5%) and sulfur (< 1%) (Neuzil et al, 1993).…”

A regional review and new insights into SE Asian Cenozoic coal-bearing sediments: Why does Indonesia have such extensive coal deposits?

“…The point is that for tropical peats only the everwet climate is really conducive to peat formation. Because most extensive peat mires are ombrotrophic (Anderson, 1964;Bruenig, 1970Bruenig, , 1990, they rely on a consistent prolonged rainfall to maintain their perched water table (Moore, 1987(Moore, , 1995, which is why the only extensive, well documented peat deposits in SE Asia occur mostly within 5 o north and south of the equator (Cameron et al, 1990;Dommain et al, 2011;Esterle and Ferm, 1994;Esterle et al, 1987;Moore and Hilbert, 1992;Neuzil et al, 1993). However, some peat mires within this ever-wet climate today are thin, with limited areal extent and are generally inorganic-rich (Phillips and Bustin (1998) and Wüst et al (2001)).…”

A Comparison of Maceral and Microlithotype Indices for Interpretation of Coals in the Samarinda Area, Lower Kutai Basin, Indonesia

“…In general, peat deposits in Indonesia are situated in a zone of annual rainfall exceeding 2.5 m. Even minimum rainfall usually exceeds evapotranspiration in the peatlands leading to ever wet conditions. Only during exceptional long, drought periods that the peat may dry out and sometimes becomes inflammable [61,62].…”