Page 266 - Carbonate Platforms Facies, Sequences, and Evolution

250
and
and
0
front
The
outline
the
to
also
BASIN
=
>¢00(
l::_·:::.:.')}j
the
t
100
Middle
Llano
MAJOR FAULT
ALBIAN REEFS
encircles
north
uplift
the
SIERRA MADRE FRONT
major structural
and
MEXICO
200 KM
LOWER CRETACEOUS REEFS
Cretaceous
the
blocks.
intra-shelf
(Kirschberg
progradation and more aggradation.
.;.· . .
... ;:-:
Maverick
Gypsum)
Stuart City shelf margin to the south (Fig. 8).
•t
ALBIAN :�EF� t
encircles the Sabinas Basin, trending down the south­
Basin,
Albian-Cenomanian
facies borders the Coahuila block on the east and
which lies between the buried Ouachita-Marathon
Albian-Cenomanian
trends of reefal carbonate with large abundant rudists
west flank of the Burro-Salado high (Smith, 1981)
The belt of rudist
both
strata; and Middle Cretaceous rocks show less lateral
The top of the Coahuila block (Acatita Formation)
J.L. Wilson
grew
area,
so
platform
OF
GULF
MEXICO
by
The Valles
rapidly
Carrasco-V,
that
platform
its
1977).
Carrasco-V.
Mexico -
developed sabkha and salinas
relief
The
McKnight Formations of Texas).
was
(1971)
extent in Albian-Cenomanian time.
developed to its
narrow
was
1000 m
. framework of northeastern
narrowed by thrusting during Laramide time.
Fig. 8. Early Jurassic tectonic
and
of Lower and Middle Cretaceous
with sulphate evap­
orites during Albian time. The East Texas embay­
The platform
its
There is a disjuncture in the platform trend where
steep sides (up to 43°) furnished coarse debris (Xilitla
its control on distribution
southern
ment and the Maverick Basin also filled with gypsum
although at slightly different times (Ferry Lake and
further
maximum
extension of the Valles platform, termed the Actopan
facies. From Wilson (1986, fig. 18).