Publication Date

1984

Document Type

Dissertation/Thesis

First Advisor

Weiss, Malcolm P. (Malcolm Pickett), 1921-

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Geology

LCSH

Foraminifera--Antigua; Coral reef animals--Antigua; Sediment control--Antigua

Abstract

The main objectives of this study are to define the foraminiferal fauna, determine the faunal assemblages, and the sedimentological controls on assemblage boundaries as they occur in the shallow coral reef environment around Antigua, B.W.I. A very narrow environmental scope, patch, fringing and barrier reef complexes less than 10m depth, was studied to gain higher resolution knowledge of Antiguan coral reef foraminiferal assemblages. Forty-six sediment samples were collected in January of 1979 sampling a fringing, patch and barrier reef normal to their trends. Using aerial photographs and a Sketch-master, high resolution ecozone maps were constructed of these reef tracts. The sediment samples were wet sieved into 5 grain-size fractions. Biogenic provenance of the reef sediments was ascertained by point count identifications of 52,200 carbonate grains in thin section with a petrographic microscope. A total of 900 foraminiferal specimens were identified from each sample location. The resulting foraminiferal assemblages were then based on 41,400 species identifications. The foraminiferal faunal diversity was quantified using the Fisher Alpha Index, and the biogenic boundaries of the foraminiferal faunas were established using Q-mode factor analysis. The study concludes first that from the specimens examined, a total of 49 genera and 93 species were recognized. Secondly, the study successfully delineates foraminiferal assemblage boundaries in a coral reef environment using Q-mode factor analysis. Biogenic provenance studies of reef sediments showed that foraminiferal abundance is: (1) inversely proportional to the abundance of coral fragments and coralline algae, and (2) directly proportional to the abundance of calcareous algae. The diversity of the established foraminiferal assemblage is: (1) strongly controlled by the percentage of fine sediment (<250u) in the samples, and (2) strongly controlled by and inversely proportional to the degree of sorting of the reef sediments.

Comments

Bibliography: pages 127-135.

Extent

vi, 142 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

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Text

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