GEOROUTE 5 – ANCÓN JUNCTION- ANCÓN VALLEY
Panoramic view of the Mountains and Gap of Ancón, spring of the Abra River, and violet limestones of the Ancón Formation.
Itinerary through the Ancón Valley, with views of the Ancón Mountains and the gap that cuts the mountains in two. The entrance to the spring cave of the Abra River is visited. This underground river is the outlet of the Palmarito River, which on the other side of the Viñales Mountains, more than 1.5 km away, goes underground at the sinkhole also called Palmarito.
GEOSITES
1. Loma del Mango
Slaty rocks
San Cayetano Formation
Karst evolution of the valley
2. Ancón Gap
Narrow valley separating two mountains
Karst canyon
Karst evolution of Viñales Valley
3. Palmarito Spring - Gap
River emerging from a cave
Resurgence
Karst
4. Paleocene Limestones
Violet-colored limestones
Limestones of the Ancón Formation
The stratigraphic column
CURIOSITIES
THE KARST SYSTEM OF PALMARITO-NOVILLO: THE LARGEST CAVE IN CUBA
The special morphology of the Viñales area owes its origin to karst processes. Water dissolves the limestones, forming caves, sinkholes, underground rivers, canyons, etc. But this process in a tropical climate gives rise to more extreme forms than in colder climates, resulting in the emblematic figures of the mogotes and gaps. It is worth highlighting this as a very important karst process found in few karst areas of the world. It involves the existence of rivers that have sections flowing on the surface and others underground. In this area, there are several cases, such as Zacarías (itineraries 2 and 4), which goes underground and resurfaces in the Indio Cave, the Santo Tomás karst complex (itinerary 8), and the Palmarito and Novillo rivers, which after flowing on the surface for several kilometers, cross the Viñales Mountains underground to emerge in the Ancón Valley, forming the Abra River.
But what we see today is the result of millions of years in which the underground rivers descended to the current height. This implies the formation of kilometers of underground galleries that have been abandoned and are now dry. Over decades, speleologists have explored both these dry galleries and those through which the underground river flows, with the spectacular result that the Palmarito-Novillo cave system has more than 59 km of passage. In 1954, Dr. Antonio Núñez Jiménez first cited the existence of the Palmarito underground river, saying: "It is curious that all these valleys communicate with each other through underground riverbeds: from Viñales, one can pass to the Ancón Valley, located to the north, through the cave that serves as the bed of the river of the same name (Palmarito). Starting in 1968, speleological explorations began by Cuban groups and mixed groups with Spaniards and English, which have continued to the present. During these explorations, a topographic map has been drawn up that allows knowing the route of the galleries. The data from the last expedition in 2019 show that, with the current route of 59 km, it is the longest cave in all of Cuba. The explorations in 2000 of a siphon in the spring of Palmarito by the group of the Spanish television program "Al Filo de lo Imposible" (At the edge of the impossible) stand out.
