Page 195 - Carbonate Facies in Geologic History

182 Pennsylvanian-Lower Permian Shelf Margin Facies

sw NE

More micrite and bioclosts in center
(fusulinids. brachiopods. algol plates)

leached 'Forom ' -edge facies
and coated
bioclosts .

Core ~ "

Undisturbed algol plates
with peloid micritic lensu

Fig. VI-9. Aneth buildup facies, Desert Creek zone. After Peterson and Ohlen (1963, Fig. 11).
See isopach map, Fig. VI-8. The low mound is as much as 70 m thick and 25 km across.
Vertical exaggeration is X 135. Steep side of mass facies into basin to northeast; slope is
between 1/2- 1/3 degree. Illustration courtesy of Four Corners Geological Society

WEST EAST

capping bed

10m

Fig. VI-tO. Sequence offacies in Late Pennsylvanian mound. Interpretation offacies in Yucca
mound, basal Holder Formation just north of Cloudcroft-Alamogordo highway, front of
northern Sacramento Mountains, New Mexico. See map of area, Fig.VI-It. For legend see
Fig.II1-l. Note flank facies on lee side composed of peloid detritus with fusulinids and
tubular foraminifera

(Fig.VI-13). Such beds are not seen in most shelf margin buildups; they must
represent a development on unusually steep regional slopes.
Normally on shelf margins this sedimentation of cores and attendant flank
beds, constituting the mound complex, was rapid enough to construct a platform
or ramp by lateral accretion. In the Sacrament os, basinward of this shelf margin,