Cockpit Country: A unique Jamaican karst environment

While writing about my tour of Appleton Rum Estate (St. Elizabeth, Jamaica), I noticed a karst geologic area called Cockpit Country to the north of Appleton's home location in Nassau Valley. As I had studied karst environments during my visit to Corso (Friuli, Italy), I decided to take a deeper look at the Jamaican instance.

Karst Background
Between Trieste and Collio Goriziano, and running from the Gulf of Trieste over the border into Slovenia, lies a rocky strip of land called the Karst (German; Carso in Italian and Kras in Slovenian) Plateau, an area whose name, according to Gams (Origin of the term "karst," and the transformation of the classical karst (Kras), Environmental Geology 21(3), pp. 110-114), derives from a pre-Indo-European word "karra" which means stony.  And stony it is.

A karst landscape forms when water interacts with soluble bedrock, such as limestone or dolostone, to create an environment that is riven with unique landscape shapes and underground rivers and caverns. This condition arises when falling rain picks up carbon dioxide (either from the atmosphere or ground) and forms carbonic acid.  This mildly acidic solution dissolves the surface of the soluble bedrock and, over time, creates distinct surface shapes and underground cavities and drainage systems.

Karst environment. Source: sourcerocks.blogspot.com

The characteristics of a karst landscape are :

• Absence of a surface water web
• Partial or total lack of soil
• Irregular plateau
• Closed depressions
• Rocky, stony surface which reflects a higher degree of the sun's radiation than say a gneiss surface
• Limited vegetation cover due to a lack of soil and surface water

Karst landscapes exist in many parts of the world but the area in the Slovene-Italian region was the first to be subjected to rigorous scientific study and, as a result, is called Classical Karst.

Cockpit Country
The map below shows Cockpit Country shaded in the darker green (A number of explanations have been advanced for the origin of the name Cockpit Country but they are confusing and unaligned. I will not present them in this post.).

The geology of Cockpit Country is shown in the map below. The underlying Igneous rocks were formed about 45 million years ago and was overlain by an older yellow limestone which was, in turn, overlain by a white limestone. This structure was revealed approximately 15 million years ago when Jamaica emerged from the sea.

Geology of Cockpit Country.
Source: https://cockpitcountry.com/geology.html

The limestone plateau rose to a height of about 2000 feet before erosion formed the regular array of round-topped, conical hills and sinks that is typical of cockpit karst.

Source: cockpitcountry.com

There are two competing theories as to the formative elements of cockpit karst: (i) solution and (ii) collapse. The solution theory proposes that heavy tropical rainfall on the limestone plateau over million of years dissolved and eroded the fissures and flushed the debris through sinkholes that connected to the sea. The collapse theory proposes the collapse of cave systems as the source of the cockpit formations.

The typical cockpit has five sides but there are documented cases of six or more sides. Other examples of Cockpit karst can be found in Cuba, Dominican Republic, and Puerto Rico.

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