Page 96 - Carbonate Sedimentology and Sequence Stratigraphy

CHAPTER 6: FUNDAMENTALS OF SEQUENCE STRATIGRAPHY 87

A)

FST

30 rate of fall =
1.25 m/ky
thickness relative SL (m) 0

-30
0 100 200
time (kyr)
distance

B)

trace of FST

30
relative SL (m) 0 rate of fall = 10 m/ky

thickness -30

100
0
time (kyr) 200
distance

C)

thickness rate of fall = 2.5 m/ky
rate of erosion = 0.25 m/ky

distance

Fig. 6.4.— Modelling runs with CARBONATE 3D (appendix B) illustrating the difficulty of avoiding formation of a falling-stage systems
tract in a system that resembles the standard model of Fig. 6.3. Forcing with symmetrical sea-level waves invariably produces a FST.
Even an asymmetric fluctuation with rapid fall of 1.25 m/ky is insufficient to suppress FST. A record resembling the standard model
requires a rate of fall of 10 m/ky as in B). The FST can also be eliminated if slower sea-level fall is coupled with subaerial erosion as in
C). However, this setup severely truncates the preceding HST.