Physical Volcanology of Pyroclastic Tephra Deposit at Batoke Mt. Cameroon, West Africa: An Over View.

Abstract

In this contribution, we report an overview of the physical attributes of pyroclastic deposit at the foot of Mt. Cameroon, West Africa. In the deposit three facies types; which are the lava flow, the lapilli and ash are common. The ash is the dominant facies and occurs irregularly in alternation with the lapilli. The most common types of depositional features include cm-dm planar beds and impact sags. We infer from field observations of facies types, clasts types and depositional features that this deposit is a phreatomagmatic fall deposit which resulted from an interaction between lava flow and surface water. The occurrence in the deposit of accretionary lapilli, impact sags, fragments of country-rock and juvenile clasts is ambiguous evidence in support of phreatomagmatic activity. The presence of a lava flow flanked by the tephra pile, the lack of accidental clasts, and the scarcity of bombs are evidence in support of a surface water-lava flow interaction.

KEY WORDS: Pyroclastic Deposit, Batoke, Mt. Cameroon,