Coral zonation and diagenesis of an emergent Pleistocene patch reef, Belize, Central America
Transect mapping and petrologic studies reveal a new depositional model and limited diagenesis of a well-exposed Pleistocene reef outcrop at Ambergris Cay, northern Belize. This emergent shelf-edge reef forms a rocky wave-washed headland at the northern terminus of the present-day 250 km long flourishing Belize Barrier Reef. Previously, the Belize reef outcrop was thought to extend southward in the subsurface beneath the modern barrier reef as a Pleistocene equivalent. The authors study indicate that this outcrop is a large, coral patch reef and not part of a barrier reef trend. Sixteen transects 12.5 m apart described in continuous cm increments from fore reef to back reef identified: extensive deposits of broken Acropora cervicornis; small thickets of A. palmata with small, oriented branches; and muddy skeletal sediments with few corals or reef rubble. Thin section and SEM studies show three phases of early submarine cementation: syntaxial and rosette aragonite; Mg-calcite rim cement and peloids; and colloidal Mg-calcite geopetal fill. Subaerial exposure in semi-arid northern Belize caused only minor skeletal dissolution, some precipitation of vadose whisker calcite, and no meteoric phreatic diagenesis. Facies geometry, coral assemblages, lack of rubble deposits, coralline algal encrustations and Millepora framework, and recognition of common but discrete submarine cements, all indicate that this Pleistocene reef was an isolated, coral-fringed sediment buildup similar to may large patch reefs existing today in moderate-energy shelf environments behind the modern barrier reef in central and southern Belize.
- Research Organization:
- Texas A and M Univ., College Station (USA)
- OSTI ID:
- 6195720
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BELIZE
CARBONATE ROCKS
REEFS
DIAGENESIS
MAPPING
MINERALOGY
PETROLOGY
ARAGONITE
CALCITE
CEMENTING
CEMENTS
DEPOSITION
DISSOLUTION
GEOLOGIC MODELS
PETROGRAPHY
PLEISTOCENE EPOCH
ALKALINE EARTH METAL COMPOUNDS
BUILDING MATERIALS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CENOZOIC ERA
CENTRAL AMERICA
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
LATIN AMERICA
MATERIALS
MINERALS
OXYGEN COMPOUNDS
QUATERNARY PERIOD
ROCKS
SEDIMENTARY ROCKS
580300* - Mineralogy
Petrology
& Rock Mechanics- (-1989)