14
Reef Lime Constructions
A
L
Fl :8~fh'~'18u, Fr
Fs
Dour , , , I '
.J
Ct
([I' I'll
fJ
1,s
,
,
,
,
C
/"s
ell
.J
ma
Fl
mo
o ~~------~~~~~~
SZ
v vvvv··~~~L.J
v" •••••• v .••
y"y"y.
vvYYyyy
70 ••• y Y
20~O--------------~o.~,5~----------~l~,5~--------------~3K~
Fig. 1.6A-E. Schemes of zonal structure of some modern reefs. A,B windward reefs of
Pacific atolls from Marshall and Lau groups; C windward flat of Indo-oceanic atoll
Kargados-Karahos; D platform reef of Western Atlantic ; E barrier reef off Jamaica;
Zones and elements of reef structure: I island; rc reef crest; rna microatolls; pr patch
reefs; pi pinnacles; irf inner reef flat; Is lagoonal slope; L lagoon; CL coastal lagoon
("boat channel"); for designations of other zones see text. Facies (biotopes): I living
corals; 2 rubble; 3 consolidated reefogenic rock; 4 coralline algae and other macrophytes;
5 sand; 6 microatoll; 7 thickets of seagrass ; 8 ancient reef base
b) Fs - Reef zone, depth 80-40m. This zone is formed by the steep
slope of the ancient reef platform on which the coral growth also started.
Corals, calcareous sponges, sedentary polychaetes and coralline algae,
which inhabit this lower boundary zone of depth distribution of
hermatypic organisms, produce here lime constructions over the ancient
reef base. This often results in the formation of steep precipices and
impending peaks at depths of 80-50 m.
c) Fs - Reef zone, depth 20-40m. This zone is also situated at the
steep slope of the ancient platform . But through receiving more light it is