Glover’s Reef Marine Reserve

Note: The data were entered in the language of the country of origin (English, French or Spanish) and there is no translation available yet.

Chapter 3. SITE DESCRIPTION

a - General features of the site

Terrestrial surface under sovereignty, excluding wetlands:

0 sq. km

Wetland surface:

0 ha

Marine surface:

200 sq. km

b - Physical features

Brief description of the main physical characteristics in the area:

See details below.

Geology:

The main Barrier Reef sits on top of a prominent northeast-southwest fault, running parallel to the coast of Belize. A series of tilted submarine escarpments (major fault blocks caused as a result of the eastward subsidence of the Bartlett Trough during the Pliocene, about seven million years ago (Schafersman 1972) (Figure 12)), have resulted in the development of three offshore atolls – two of these (Lighthouse Reef and Glover’s Reef) being located on the third, most easterly escarpment furthest from the mainland. Glover’s Reef Atoll is the most southerly of the three atolls of Belize, covering approximately 200km², being 35km long and up to 7.5km wide. The Atoll sits on metamorphic rock, which has been identified at a depth of between 777 m and 959 m below Glover’s Reef. This base rock is overlain with about 250 m of calcareous siltstone of Late Cretaceous age (100 million years ago), and 560 m of Tertiary (64 million years ago to the present) reef accumulation. It is thought to have been formed in areas where limestone build-up has been at a rate equal to or greater than the subsidence caused by the movement on the faults, resulting in the formation of carbonate platforms surrounded by water that gets progressively deeper to the east, reaching 4000m. The reef platform is probably a wave-cut reef of last interglacial age on which the overall physiography of the atoll, including the rim, lagoon, patch reefs, and channels, have developed following rising sea levels.

Sediments from reef and fore reef are comprised of fragments of coral, red algae and Halimeda. In contrast, sediments of the back reef area contain more mollusk fragments and have lower percentages of Halimeda (Gischler 1994).

Sediments associated with the patch reefs are poorly sorted coarse-grained carbonates, composed primarily of Halimeda, coral, coralline algae, mollusc and other skeletal particles. The lagoon floor is muddy, composed of fine-grained carbonate sand, with the sand fraction rich in Halimeda, mollusc and foraminifer grains (James & Ginsburg 1979).

Sand dunes:

Long Caye North (Lomont Caye) This small shingle caye or islet originally had an area of 0.5ha but was heavily impacted and eroded by Hurrican Mitch in 1998. It now has very little sand and has the characteristic of a sandbore.

Others:

Mean annual precipitation (in mm) 1750mm.