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A re-evaluation of facies on Great Bahama Bank I: new facies maps
of western Great Bahama Bank
JOHN J.G. REIJMER
*†1
, PETER K. SWART
2
, THORSTEN BAUCH
*3
, ROBERT OTTO
2
,
LARS REUNING
*4
, SVEN ROTH
*5
and SUSANNE ZECHEL
*6
*
IFM-GEOMAR, Leibniz-Institut für Meereswissenschaften, Dienstgebäude Ostufer, Wischhofstr. 1-3,
D-24148 Kiel, Germany
†
Centre de Sédimentologie-Paléontologie, Laboratoire (EA 4229) 'Géologie des Systèmes et des Réservoirs Carbonatés',
Université de Provence (Aix-Marseille I), 3, place Victor Hugo, Case 67, F-13331 Marseille Cédex 3, France
ABSTRACT
A re-evaluation of the sediment distribution patterns on western Great Bahama Bank
shows a facies distribution with two end-members. Coarse-grained sediments in the
north, west and south of the bank surround a mud-dominated realm located on the
western leeward side of Andros Island. This facies distribution is comparable to earlier
maps, but shows considerably more detail and a complex distribution from grainstones
to mud-rich wackestones. As in other carbonate platforms, sediment distribution
appears to be infl uenced by (1) tidal currents, (2) prevailing wind direction, and (3)
the interaction of the rate of Holocene sea-level rise with the pre-existing Pleistocene
topography. The grain-size distribution very precisely refl ects current-infl uenced and
protected areas on the platform. The correlation between the distribution of pellets and
the 63-125 μm grain-size fraction most probably refl ects the predominantly biological
origin of this grain size. Aragonite dominates the mineralogy on the platform, low-
magnesium calcite and high-magnesium calcite occurs in higher quantities only in a
few environments on the platform.
Keywords
Facies distribution, grain-size, mineralogy, Great Bahama Bank, Holocene.
INTRODUCTION
spatial distribution of sediments on Great Bahama
Bank (GBB) is based on the work of Illing (1954),
Ginsburg
et al
. (1958), Newell
et al
. (1959) and
Purdy (1963a,b). Valuable as these early descrip-
tions are, it is the aim of this study to re-evaluate
the distribution of the surface sediments on GBB
using samples collected from precisely located
points (Fig. 1b; established using GPS) and to
quantify not only the types of sediments pres-
ent, but also the mineralogy, grain-size distribu-
tion and skeletal and non-skeletal content. This
paper together with a companion paper (Swart
et al
., 2009) takes a new look at the surface
facies and geochemistry of sediments from Great
Bahama Bank.
Various maps show sedimentary facies on
GBB or in the Bahamas in general (Ginsburg
et al
., 1958; Newell
et al
., 1959; Purdy, 1963a,b;
Ball, 1967; Enos, 1974). In all these studies sedi-
ments were classifi ed using distinct facies types
with comparable subdivisions. All maps show
that skeletal sediments occur mainly on the
margin of the bank whereas non-skeletal grains
The Great Bahama Bank (Fig. 1a) has served as
an inspiration for geologists in understanding
modern processes of carbonate sedimenta-
tion since the pioneering work of Field (1931)
and Illing (1954). Most of our knowledge of the
1
Present address: VU University, Faculty of Earth and
Life Sciences (FALW), De Boelelaan 1085, 1081 HV
Amsterdam, The Netherlands (Corresponding author:
E-mail: John.Reijmer@falw.vu.nl).
2
Marine Geology and Geophysics, Rosenstiel School of
Marine and Atmospheric Science, 4600 Rickenbacker
Causeway, Miami, FL 33149, USA.
3
Present address: Schlumberger Oilfi eld Services D&M,
Hamrasletta 15, 4056 Tananger, Norway.
4
Present address: RWTH Aachen University, Wüllnerstr. 2,
D-52062 Aachen, Germany.
5
Present address: Nummerical Rocks, Stiklestadveien 1,
7041 Trondheim, Norway.
6
Present address: TU Bergakademie Freiberg, Institut für
Geologie und Paläontologie, Bernhardtvon-Cotta Straße 2,
09596 Freiberg, Germany.
