Burial and preservation of a fossil forest on an early Permian (Asselian) volcano (Merangin River, Sumatra, Indonesia)

The Early Permian (Asselian) Mengkarang Formation of the western Jambi Province, Sumatra, is well exposed in the valley of the Merangin River. No consensus regarding the depositional environment of this section had been reached hitherto. This section preserves abundant evidence of a Permian forest, named the Merangin Fossil Forest herein, which grew at the foot of an active volcano, where pyroclastic flows often made way and destroyed the vegetation and where epiclastic reworked pyroclastics rapidly entombed the vegetation. The present assessment is based on a detailed study of three localities using multiple lines of evidence, including petrography, silica typing including hot cathodoluminescence microscopy and spectroscopy, and palynofacies analysis. In situ Agathoxylon was near enough to the volcanic slope to be buried rapidly, shallow enough to avoid extreme crystallization in the lumina, and far enough from the metamorphic centre not to get recrystallized. All these combined contingencies make this a most unique find that provides significant insights into a rarely studied palaeoecological setting from the Early Permian.