Page 307 - Carbonate Facies in Geologic History

294 Shoaling upward Shelf Cycles and Shelf Dolomitization

TEXAS CO. *1 EDENS
NAVARRO Co. TEXAS
BASAL BUCKNER 8 UPPER SMACKOVER
JURASSIC OF EAST TEXAS

.
gray onhy. 8697'- > Evaporite Phose
/ " /
" /
It. brn. / " L /0
0
o /0 "/ . pelleted Clearwater
•
/"
0
/ / Shoaling Phose
1/ . .
/
/ .
. . . Oolite Subphase
8 7~
.". grainstone ( pyr )
I. gy. L IL mudstone
I. gy. ~\I X' ~10 pelleted
r.-
-SI""\-
_-.01 __ dolomitic mud
orgill. mud
"
L brn. I J dense 8 805'· Normal
gray -I - mudstone Marille
-
-
Phose
-
-
----r -- orgill. muds!.
-
-
I-r I" dolomitic
gry. -1-
--
brnish. 1---. "b mudstone
to
gray /"\1/"\
wi
I=- I-=- orgill.
stringers
I
-::.I"~ I" pelleted
----I ~
1 ,I orgill. muds!.
I
I-=-~I
I Beginning
1 1- Clastic
Phose
1 C@J Ooid_
I-I laminated ~ Crinoid_
mudstone
-~I----
-
---- orgill. 8 996'- 1:1"'1 0 1 Pellets and shelly bioclasts _
Fig.X-11. Smackover (Upper Jurassic) facies in east Texas well in a typical shoaling upward
cycle with about 30 m (100 feet) of upper oolite and dolomitized peloidal grainy sediment and
an evaporite cap. Lower 60 m is dark brown argillaceous bioclastic wackestone with brachio-
pods and crinoids. Depths on log are marked in feet
The very thick lower dark lime mudstone or wackestone of the gulfward
Smackover much resembles the Diyab-Darb of Arabia. It contains the pelagic
crinoid, Saccocoma, Favreina fecal pellets, and miscellaneous crinoid fragments.
This dark limestone with the upper Smackover oolitic pellet grainstone and
overlying tidal flat dolomitic mudstone and anhydrite (Buckner Formation)