Page 319 - Carbonate Platforms Facies, Sequences, and Evolution

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296
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lmlE
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-....r
f''''"''!i
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lctd
or
or
mega
widespread
redeposited
Fine
Large
KEY TO
Slump
ill
Current
IJ
Vertical
in this succession.
Stylolites
breccia
Limestone,
Radiolarite
Fold
Marlstone or
marker
Thin-bedded
Graded
Ripples,
Horizontal
calcarenite
bed
forms
Channeling
SYMBOLS
Tc
Shale and siltstone
Cross-Statification,
in
Plane Lamination, Tb
a
plane lamination,
or
Burrow/Trace
Trace
limestone
Tc
Thin-bedded limestone,
Horizontal Trace Fossil
limestone,
Bedding,
Td
which
USED
Thickly bedded to massive
with
scour
Ta
Fossil
section
Fossil
Siliceous radiolarian mudstone
can
Scott, Amoco written comm., 1983).
(J)
<(
0
0
w
w
m
w
::I
z
::::;
::I
0
(terrigenous)
Intraformational truncation surface
conglomerate/breccia,
calcilutite
be
calcarenite
AS
K.F.
cs
Ox
MS
Val
Tur
Alb
Cen
Con
Tith
thick (23-37 m)
calcirudite
between the eastern and the western nappes (Figs 8
and
& 9). It contains huge blocks of thin-bedded slope
HR-1 (Robert
limestone (up to 1 km across) and rounded boulders
correlated
Albian
argillaceous interbeds
calcarenite and calcisiltite
Turonian
Tithonian
Coniacian
Oxfordian
Valanginian
Cenomanian
Clast-support
and
Amalgamation
Watts and C.D.
unit
Matrix-support
upper
Fabric
IN STRATIGRAPHIC COLUMNS
Fabric
Blome
Surface
part,
consists
consists of megabreccia, other calciclastic sediments and minor radiolarian chert.
of
a
intraformational
calcirudite
thick
Formation (q) forms the rubble-covered slope along the axis of the south-plunging syncline.
and 15.
is
sequence
of
calcirudite (Fig.
interbedded
and the upper A Member (a). The A Member lies stratigraphically below the distinctive dark-coloured chert
8).
bedded calcilutite of the upper A Member.
(C) The upper part of section Fy-1 is exposed along the axis of the major syncline at Jebel Fayad. Thin-bedded
with
(A) In the eastern nappe, section HR-1 (dashed line) shows a complete but overturned sequence of the Mayhah
In
Fig. 4. Key to symbols used in
(b) which is followed by light-coloured limestone the D Member (d) of Mayhah Formation. Chert of the Qumayrah
over the Qumayrah Formation (q). The Mayhah Formation consists of thin-bedded lime mudstone of the lower oolite
stratigraphic columns in Figs 3, 8
equivalent ('lg'), the shaly interval with megabreccias (sh), the lower Mayhah Formation (Mhl), and the upper Mayhah
of coralline limestone. The upper calcarenite sub­
Formation and its conformable contact with the stratigraphically higher Qumayrah facies. The A Member of the Mayhah
thin­
Fig. 5. [Opposite] Outcrop photographs of sections HR-1 and Fy-1, the stratotypes for the eastern nappe and western nappe.
bedded calcilutite and passes gradationally into thin­
Formation is further subdivided into the lower oolite (1g), the shaly interval with megabreccias (sh), upper calcarenite (ug),
limestones of the upper Mayhah Formation (Mhu) are unconformably overlain by the Qumayrah Formation ( q) which here
(B)Section Fy-1 is the most complete sequence of Mayhah Formation limestones in the western nappe. The base of the
section is cut by an out-of-sequence thrust fault which truncates synclinally folded lower Mayhah Formation which is thrust
Formation (Mhu). The upper part of the section is shown in Fig. SC (below); note the lack of the B Member chert interval
bedded, channellized, redeposited oolitic calcarenite
lenticularly
the