Geology Reference
In-Depth Information
Fig. 16.4
Fluvial to estuarine facies in rhythmites from southern
Illinois. (
a
) Low angle planar forsets in medium-grained sandstone.
Foresets are delineated by sand- and silt-sized accumulations
of coalified plant debris. Sample from immediately above
Murphysboro Coal in southwestern Illinois. (
b
) conglomerate
within lower part of IVF sequence consisted of locally derived
clasts of limestone (
light colored
), poorly cemented sandstone,
sideretic chips. From lower IVF in Tonganoxie Sandstone,
east-central Kansas. (
c
) Outcrop in southern Illinois of Abbott
Formation exhibiting mostly planar forests delineated by iron-
cemented zone (originally mud drapes). Cyclicity within this
outcrop has been described by Kvale and Archer (
1991
) and
Archer (
1996a
)
