Page 79 - Carbonate Facies in Geologic History

66 Outline of Carbonate Petrography

~ CALCISPHERES, CHARA REEFY OR ALGAL
INDETERMINATE

~ DASYCLADACEAN ALGAE ~ BRACHIOPODS

~ SPICULES ~ CRINOIDS
~
~ PLATY-PHYLLOID ALGAE I" "I ANGULAR BIOCLASTS
1'"\"

I~ I STROMATOLITIC ALGAE r:-:l PELOIDS
L:....:..J
OOIDS & PISOIDS
~ TUBIPHYTES ~
®
~
~
I~I ONKOID-ALGAL BALLS MOLLUSKS-BIVALVES
GASTROPODS
~ ~
TUBULAR FORAMS
GENERAL FORAMS & [2J OSTRACODS
W MILlOLlDS
LARGE FORAMS (INCLUDING RUDISTS, CAPRINIDS &
REQUIENIDS
1001 FUSULINIDS ~
MASSIVE SUBSPHERICAL CORALSI(~ I
~ OYSTERS

MASSIVE, SUBSPHERICAL HORN CORALS
101 STROMATOPOROIDS ~
DENDROID, FASCICULATE SPONGES
[B CORALS ~
DENDROID, FASCICULATE [I1] ANHYDRITE, GYPSUM
IS(" I STROMATOPORO IDS /\1\
1fA\1 AMPHIPORA ~
HALITE

Fig. III-I. General legend for particle and fossil types and for standard microfacies. The brick
limestone pattern always indicates a micrite matrix and a large arc above a fossil symbol
means boundstone or "reefy" tendency
SMF-13 Onkoid biosparite grainstone (Fliigel, 1972) (Plate IX B)
Algally coated particles formed in a moderately high energy, very shallow water
environment.
SMF -14 Lag (plate IX C)
Coated and worn particles, in places mixed with ooids and peloids which are
blackened and iron-stained,with phosphate. Allochthonous lithoclasts may be pre-
sent. These lags are characteristically thin deposits, representing slow accumulation
of coarse material in zone of winnowing.
SMF -15 Oolite (Fliigel, 1972), ooid grainstone (Plate X)
Well-sorted, well-formed, multiple-coated ooids ranging commonly from 0.5 to
1.5 mm in diameter; commonly the fabric is overpacked. The sediment is always
crossbedded. It originates through water movement on oolite shoals, beaches, and
tidal bars. The best-formed ooids are typically produced on tidal bars.