The Origin of Guanacaste
According to the remains and geological formations found so far, for about 80 million years, there was a period called the Upper Cretaceous (96-65 million years ago) What we know today as Costa Rica at this time confined to a small island that limited with what we know today as Tempate, near Cabo Velas on the Nicoya Peninsula, Guanacaste. At this time the location was in the west compared to the place today. The sea at the northeast was not deep.
Plants and mammals were beginning to have a great diversity but still unknown which organisms arrived because the nearest coast was South America, which makes them very few. It is said that there was a small fauna of leaf miners caterpillars, grasshoppers, aphids, ants and termites.
In the period known as the Lower Tertiary Eocene (53-34 million years ago) a large part of the Nicoya Peninsula, known today as Santa Cruz in the south was a sea where the island had grown and occupied from Cabo Velas up to Playa Samara and from Nicoya up to Ostional Beach.
By this time many plants and animal pollinators where already being naturally distributed. Guanacaste, was an island, that had little interaction until the island joined the rest of the continent. The weather was cold and dry in some parts of the planet but always dominated the tropical forest with seasonal regions. It Was the beginning of the butterflies flying in the day and at night you may see some relatively large mammals because that had reach the island.
In the Middle Miocene (16-11 million years ago) Guanacaste had two islands. The smallest was the entire Peninsula of Santa Elena that carries 85 million years of being emerged. The greater was the Nicoya Peninsula, still under the sea where the regions of Cabo Blanco, and the triangle of what we know today as Jicaral, Bajo Negro and Curú.
The weather here was cold cycles of dry and humid heat. The vegetation was poor and often deciduous domain could therefore have dry sections in the islands, where the climate favored birds and larger mammals.
Meanwhile much of North America was covered with ice, Guanacaste began sinking with the rest of the isthmus built by Costa Rica and Panama. The isthmus hill has 3 million years. It became common several types of rodents and predatory mammals. When the isthmus was closed by the binding of Costa Rica to North and South America a variety of microorganisms such as fungi, plants and animals had not been able to pass the barriers, then crossed the sea to the north. Other successful cases were hairless foxes, the agouti, monkeys and horses.
In the Pleistocene (1.65-0.01 million years ago) there was a big chill in the weather. Areas of medium heights were from Santa Cruz to La Guaria and had a temperature of 20 º C while the rest of the Peninsula reached 23 º C.
Temperatures were even lower in the highlands of Guanacaste and reached 15 ºC. Today the climate is obtained in the Rincon de la Vieja Volcano zone. For this reason, global glaciations caused a lot of freeze water at the poles and get to a sea level down to 80 m. With that, the Gulf of Nicoya is exposed and formed in what is known today as the Valley of Nicoya.
Probably in the heights of the Guanacaste Mountain Range, the highly active volcanic cones began to form a relief that would be occupied by simple plants such as bryophytes and lichens then going to be more complex plants. It is important to remember that the cones at Rincon de la Vieja, Orosi and Cacao are more recent.
The Rincon de la Vieja is the most active volcano of Guanacaste and its current form has some 50,000 years. His solid occupies 250 km, including six active sites and 3 inactive volcanic emissions. In the Pleistocene period had violent eruptions. It is believed that in a large explosion of this volcano formed the Santa Rosa Plateau that extends into Liberia. He currently has a gas outlet, hot water and water mixed with soil, it produces what is known as pots and lahars or mud flows. This represents a danger to people living on the Caribbean side of the volcano. Recently there have been efforts with blasts of steam, gases and ash fall in the year 1983, 1991 and 1995.
In Santa Rosa Plateau had opened areas that experts said the lower areas must raise to savanna with trees of various generations. In the dry hills nearby we found varieties of cactus, agaves and several species more.
When the volcanic mountain chain rises, climate and vegetation were similar to the current back. Large mammals that inhabited Guanacaste at that time included the family of elephants, horses, edentates as glyptodon, the megatherium and mylodon.