Research Station Carmabi
On Curaçao four major geological formations can be found:
(1) The Lava Formation consists of basalt and represents the oldest geological feature on the island. This formation was formed below sealevel during the Cretaceous Period (~87Ma). The basalt is locally at least 5km thick suggesting the island’s origin started that deep below the ocean surface and is geologically “younger” towards the West of the island.
(2) The Knip Formation that consist mostly of old Radiolaria that bloomed in the warm water springs after the main eruptions that created Curaçao’s vulcanic core ended.
Their skeletons sank to the bottom during periods of low food availability and formed a layer consisting of silicium (SiO2) rather limestone (CaCO3). Subsequent diagenesis hardened these layers into Silex formations (~75Ma) of which the Christoffel Mountain, the largest mountain on the island, is the best example.
(3) The Mid Curaçao Formation originated through a reorganization of the geological features that were formed thusfar (~65Ma). A series of endogenous forces, likely earthquakes, but also the slow rising of the island (0.25-0.50mm yr-1) associated with tectonic movements, resulted in sequential sand and rock deposits in trenches or valleys on the island or on the slopes of the island below the ocean’s surface. These formations are generally referred to as “turbidites”.
(4) Limestone Formations consisting of the Ser’i Domi Formation and the limestone Terraces that were only formed ~5Ma. Except for sporadic rock formation in the Eocene, no significant rock formation occured on Curaçao between the formation of the Mid Curaçao Formation and the recent Limestone Formations. Five million years ago, the rising of Curaçao resulted in the birth of two islands ‘Banda’bou’ and ‘Banda’riba‘, representing the West and East side of present day Curaçao respectively. Coral reef formation occured in the shallow waters around these islands. These oldest reef formations are still visible as the sloping limestone mountains along the Leeward shore (i.e. The Ser’i Domi Formation). The Limestone Terraces then arose as coral growth tracked the variable sealevels associated with glacial- and interglacial cycles. The oldest (or “highest”) terrace was formed ~2Ma.
The subsequent glacial period caused sealevels to drop resulting in a “lower” reef terrace (~1Ma) on which the town Tera Kora is built. Two younger terraces were formed 0.5Ma and 0.03Ma ago, the latter now forming the Hato Plain. The most recent glacial period occured 0.02Ma ago and a reef was formed that during the subsequent interglacial period (~0.01Ma) “drowned” and can now be found underwater at depths >60-80m and is commonly referred to as the “second drop-off”.