Page 51 - Carbonate Platforms Facies, Sequences, and Evolution

a
b
46
NE
SW
The
high
were
i":" :
which
tation
· .
energy,
shelf
rate
were
micritic
degree
parallel
-
reworked
was
of
margin
coating
20 m
from
bedded
•
well-reworked
· . . ·.·.· . . · . ..... ·
•
and
parts
fully
parallel
micritization
of
·
Marine
pore
They were produced by erosion
·
probably low as
-
li mestones
the
subaerially exposed or
and
shelf interior
marine
bedded
· . ·.·.:.· · . .. ·.··.· . . .
R.L.
shoal
bridging
.
Cemented
: .
suggested by
from shoal
abundance
li mestones
-
se-
are also interpreted as having been deposited orig­
cemented layers on the seafloor. Type B intraclasts
inally in a high energy, fully marine environment.
environment.
of
textures
complex
are interpreted as a pedogenic texture formed in a
calcrete profile. This indicates that these intraclasts
and reworking of
the
peloids. Type A intraclasts were derived from a high
Horizon
top
shelf interior
.
top
· ·· ·· . ...•
of
::': ·�: : . . · . : .·
of
·• ·· . . . . .
Gawthorpe and P.
0 No
face
.
face
within
shelf
stacked
Data
diagenetic
the
-
radialfibrous
[21 Microfacies
[ill] Microfacies
margin
shells,
Gutteridge
2
shoal
origin
a
in sedimentation.
. · . . . . . . :: . : . . .. ·:
·
-
·
cement
· . .
: . .
10m
:
high
is
and its
-
·
: . .
.
complex.
: :
Covered
degree
·
. .
The
of
[J Microfacies
lii§] Microfacies
20m
onlapping sub-sequences (see Figs 4 and 6 for the location of sequence and sub-sequence boundaries).
interpreted
3
4
occurrence
local
Section
as
in
a
.
.
the
.
winnowing.
the occurrence of wackestones in parallel bedded carbonates above and below the shoal sequence boundaries and in
.
-
. ·. ·. ::- · :-�-:- :: · -:-:.<_- .
syndepo­
Works Quarry (SK159820). Note the dominance of grainstones and packstones (microfacies 1 and 2) in the clinoforms and
Fig. 9. Examples of microfacies distributions in shoal sequences. (a) Pin Dale (SK159822). (b) Sequence 3, Hope Cement
sitional marine phreatic cement because of its early
The
bedload processes or, in the case of layers of highly
layers on the seafloor is attributed to periodic pauses
grainstone intraclasts. The occurrence of cemented
sorted
microfacies 4 which was deposited in sheltered areas
quence boundaries. Type C intraclasts are similar to
preferential
sw
alignment of allochems is attributed to deposition by
NE