Geological History

VIEW FULL IMAGE

Oligocene

During the Oligocene (some 34 to 23 million years ago), the coral reefs were buried under thick sediments originated by volcanic activity, and eventually emerged as a series of islets in what today is Costa Rica.  These sediments drifted, transported not only in suspension by fluvial and ocean currents, but also during major events caused by ocean floor torrents, forming high-speed torrents (turbidity currents).  Currently the deposits generated by these events exist as consolidated rocks; they are noticeable in the outcrops and cuts along the southern Inter-American highway (in the localities of Lagarto and Zapote), and were named Térraba Formation.  These rocks are sandstones and shales.

VIEW GLOSSARY

» Eocene

» Miocene

» Pliocene

» Quaternary