Geology Reference
In-Depth Information
A
A
B
C
D
E
Qu
a
rry
DS E
400
DS C
375
SB C
350
DS E
DS D
DS C
Rhodolith banks
325
DS B
Terracing
DS A
A
B
B
Growth Fold
C
D
E
Quarry
DS E
FST
400
375
DS C
DS E
350
DS D
DS C
Rhodolith banks
325
DS B
DS A
Growth Fold
200 m
Coralline
packstones
White fine
pack/wackestones
of DS D
Fossiliferous
packstones
White fine
pack/wackestones
Yellow
packstones
Yellow
wackestones
Reef core
Reef talus
Sequence boundary (SB)
SB inferred
Fault
Interbed. conglom.
& wackestones
Bioclastic
pack/wackestones
Marl &
sandstones
DS A
Growth fold
Bedding
Fig. 11.
Nijar Ridge - bedding, lithology and depositional sequences. Number 400 in top left corner of both profi les
indicates elevation in metres. Letters A-E denote hills used as topographic reference points. After Warrlich
et al
. (2005),
modifi ed.
Simulated toplap surface
Present topography
#
Simulation
&
Field observation
100 m
Fig. 12.
Nijar Ridge - fi eld observa-
tions and computer simulation of FST.
After Warrlich (2001). Important mod-
elling settings: platform margin pro-
duction 4500
Simulated facies
Mapped facies
Platform margin
Coarse-grained, redeposited
Pelagics and fine-grained redeposited
Porites
reefs
m yr
1
, marine erosion
Proximal slope (skeletal packstone)
m yr
1
, mean rate of sea-level
1500
Distal slope (fine pack/wackestone)
m yr
1
.
fall 74
(5)
(after Pomar, 1991, 2000): a hierarchy
of prograding sigmoids and sigmoid bundles
was recognized and tentatively correlated with
orbital cycles. Plotted are rates for co-sets of
sigmoids, interpreted as expression of the
100 kyr eccentricity cycle. Range of sea-level
fall in the co-sets is estimated as 60-70 m
based on Pomar (2000). Assuming the FST
represents half of a 100-kyr cycle, the range of
rates of fall is 1200-1400
Mallorca
168-177 m. This yields rates of fall of about
630-665
m yr
1
.
Figure 16 shows that all FST case studies con-
sidered actually plot in the stability domain of the
FST predicted by modelling, even if one assumes
that their production rates were only 500
m yr
1
.
m yr
1
.
DISCUSSION
(6)
(after Warrlich
et al
., 2005): the FST of
depositional sequence E is well constrained
by fi eld data and a good match with model-
ling runs. Duration of the FST interval is esti-
mated as 0.266 Myr and the range of fall as
Nijar
The modelling runs provide a reasonably clear
picture about the conditions required for develop-
ing a FST or the continuous unconformity of the
standard model during sea-level fall. The key
