Page 143 - Carbonate Sedimentology and Sequence Stratigraphy

134 WOLFGANG SCHLAGER

situation bank-top production is high but accommoda- ➤ Diagenesis seems to accentuate sequence boundaries
tion small such that most excess sediment is shed down because exposure and flooding of the platform during
the leeward slope. Slope sediment is mud-rich and low sea-level cycles change the composition and amount
in sandy turbidites. Most turbidity currents probably of sediment on the slope (Fig. 7.38). During high-
bypass the slope and deposit their material on the basin stands, sediment flux from platform to slope is high and
floor, similar to the situation in other Bahamian basins the slope sediment therefore contains large amounts
(Schlager and Chermak, 1979; Mullins et al. 1984; Har- of metastable aragonite. During lowstands, sediment
wood and Towers, 1988). flux is reduced and the slope sediment is low in arago-

WSW Santaren Channel Site 1004 Clino Great Bahama Bank ENE
Site 1006 Site 1007 Site 1003 Site 1005 Unda
0

0.5
(ms) Pleistocene - Holocene

1.0
TWTT Pliocene
1.5
Miocene
Base of Neogene
Line 106 Western Line
10 km
Fig. 7.34.— Interpretive line drawing of seismic profile of southwestern Great Bahama Bank showing platform-to-basin correlation of
17 Neogene sequence boundaries. After Eberli et al. (2002), modified.

CLINO UNDA
Western Great Bahama Bank Fig. 7.35.— Time lines of
mbmp mbmp
0 0 magnetic reversals vs. se-
b
platform 50 Brunhes - Matuyama (0.73 My) a SB-B 50 platform quence boundaries. Time
lines and sequence bound-
c
Top Olduvai (1.66 My) reef aries diverge and converge
100 Base Olduvai (1.88 My) SB-C 100 margin but never cross. After
reef Eberli et al. (2001), modi-
150 SB-D 150 fieds.
margin 200 d 200 deep shelf

slope 250 Reunion event (2.14 My) 250
platform derived e SB-E

upper 300 Top Gauss (2.48 My) [erosional?] f SB-F g 300 reef
350 350
SB-G margin
pelagic 400 Base Gauss (3.40 My) top C3An (5.35 My) h 400
pelagic 450 450 shelf platform

slope C2Ar/C3n (3.88 My) SB-H
pelagic 500 Base Messininan disconformity 2 kilometers

lower 550 sequence boundary
chronostratigraphic datum
600
Base C4n (mid-Tortonian)
lower slope
650