Bonaire National Marine Park

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Chapter 3. SITE DESCRIPTION

a - General features of the site

Terrestrial surface under sovereignty, excluding wetlands:

60 sq. km

Wetland surface:

170 ha

Marine surface:

27 sq. km

b - Physical features

Brief description of the main physical characteristics in the area:

See below

Geology:

Bonaire lies on a conservative plate boundary, where the South American and Caribbean Tectonic Plates meet and slide past one another. Along with its sister island of Curacao and the oceanic islands off Venezuela’s north coast, it has been travelling eastward at a slow but steady rate having originated in the Pacific in the vicinity of the current day Galapagos Islands.

The geology of Bonaire is complex, with the core of the island consisting of strongly folded and faulted rocks of volcanic origin, silica rich sediments and turbidites (debris deposited from an underwater landslide) formed during the Cretaceous era some 120 million years before present (Beets, 1972a; Beets, 1972b)). Overlying this are later fossil reef and reefgenerated calcareous (calcium rich) deposits. It is these limestone formations which make up the coastline in the form of coral-rubble beaches (coral shingle and calcareous sand) or iron shore, except in the north where low limestone cliffs are found (see Image 1) (Zonneveld, Buisonje & Herweijer, 1972) Klein Bonaire consists entirely of limestone formations (Buisonje, 1974) which are the remains of emergent reefs. Substantial changes in sea level have left up to four stranded terraces above the present mean sea level on Bonaire, and one below. These terraces can generally be distinguished by "solution notches" (undercutting caused by chemical erosion, physical erosion and in some cases biological erosion (see Image 2) in the elevated seaward facing limestone cliffs.

Sand dunes:

Length of sandy beaches: 1.8 Km

Others:

FRESHWATER INPUTS

Mean annual precipitation (in mm)

Average rainfall is just 490.5 mm/year. Rainfall is unequally distributed geographically, with approximately four times as much rain falling in the northern portion of the island as in the south. The rainy season begins at the end of October and lasts until around the beginning of January; a second, shorter rainy season occurs in June/July.