We present a radiolarian biostratigraphic study of the metacherts of the
El Tambor Group ophiolites (South Motagua Unit), Guatemala. The
ophiolite sequence comprises MOR pillow metabasalts, massive
metabasalts, metacherts and micaschists. The age of the studied
metacherts is referable to the Late Jurassic (Oxfordian-Kimmeridgian).
The radiolarian assemblage described in this paper is the first Jurassic
finding in the ophiolitic MOR succession of the Motagua zone and
represents a valuable tool to constrain the geodynamic evolution of the
Caribbean area.
A review of the ages of Jurassic rocks associated with the ophiolites
from the Caribbean area is also reported.