Deposits of Peat in Costa Rica

Abstract

Peat deposits of Costa Rica developed in major alluvial plains of the Atlantic coast (back arc basin) and in the mountains in small depressions of the magmatic arc.

The peat swamps of the Caribbean coastal plain display both elongate morphology typical of a back-barrier environment, or irregular forms associated with inundated plains of meandering rivers. The peat deposits range in thickness from 0.5 m to 15 m. Calorific values vary between 2975 and 4695 Kcal/kg (dry base) and display low sulfur values. The organic content is mainly fragments of Yolillo (Raphia), a palm which is common in peat bogs in the Caribbean zone. The inorganic components were derived from the magmatic-arc mountains located to the south, which provided sediments principally of volcanic origin.

The peats in the intermontane depressions are found in the higher zones of Costa Rica (magmatic-arc of the Cordillera de Talamanca). These types of peat are poorly developed and have irregular shapes. The cold climate, high precipitation, poor drainage, and the lack of inorganic sedimentation produce a peat low in sulfur with a relatively high calorific value. The most important organic components here are sphagnum, grasses, ferns, and sedges.