Chapter GB

BIOSTRATIGRAPHY, EASTERN ROCK SPRINGS

UPLIFT, GREATER GREEN RIVER BASIN

By D.J. Nichols

in U.S. Geological Survey Professional Paper 1625-A

U.S. Geological Survey
GB-ii

Contents

Biostratigraphy....................................................................................................GB-1

References ..........................................................................................................GB-2

Figures

GB-1. Biostratigraphic reference sections in the eastern part of the Greater

Green River Basin.

GB-2. Occurrences of Momipites and Caryapollenites pollen and the

definition of palynostratigraphic zones P1-P6.

GB-3. Palynostratigraphic zones of the Fort Union Formation in the Greater

Green River Basin.
GB-1

BIOSTRATIGRAPHY

• The most common fossils in coal and coal-bearing rocks are pollen grains

and spores. Thus, biostratigraphy based on pollen and spores

(palynostratigraphy) has been used to determine the age of coal-bearing

rocks in the Greater Green River Basin.

• Palynostratigraphy in the Greater Green River Basin is based on

previously conducted palynological studies of outcrop sections in the

region, which established the biostratigraphic framework.

• The ages of individual coal beds or zones were determined by analyses of

samples collected more recently from reference sections in coal mines

(fig. GB-1) in the eastern part of the basin, on the eastern flank of the

Rock Springs uplift.

• Five of the six palynostratigraphic zones (fig. GB-2) within the

Paleocene are present in the eastern part of the Greater Green River

Basin. On the Rock Springs uplift, the principal Paleocene coal zone is

the Deadman zone, which lies in Zone P3, in the middle part of the

Paleocene (fig. GB-3).
GB-2

REFERENCES

Hettinger, R.D., Honey, J.G., and Nichols, D.J., 1991, Chart showing

correlations of Upper Cretaceous Fox Hills Sandstone and Lance

Formation, and lower Tertiary Fort Union, Wasatch, and Green River

Formations, from the eastern flank of the Washakie basin to the

southeastern part of the Great Divide basin, Wyoming: U.S.

Geological Survey Miscellaneous Field Investigations Map I-2151, 1

chart.

Nichols, D.J., and Ott, H.L., 1978, Biostratigraphy and evolution of the

Momipites-Caryapollenites lineage in the early Tertiary in the Wind

River Basin, Wyoming: Palynology, v. 2, p. 93-112.
Figure GB-1. Biostratigraphic reference sections in the 

eastern part of the Greater Green River Basin.

Biostratigraphic age determinations 

of Paleocene coal beds in the Great 

Divide Basin part of the Greater Green 

River Basin is based on palynologic 

analyses of samples from mines in the 

Point of Rocks-Black Butte coalfield, on 

the eastern flank of the Rock Springs 

uplift. The locations of these mines 

WYOMING are shown by the red dots on the map.

COLORADO

Great

Divide

Basin

Washakie

Basin

Rock

Springs

uplift
Figure GB-2. Occurrences of Momipites and Caryapollenites 

pollen and the definition of palynostratigraphic zones P1-P6. 

L, M, and U designate lower, middle, and upper Paleocene.

P1

P2

P3

P4

P5

P6

U

M

L

M. inaequalis

M. leffingwellii

M. waltmanensis

M. wyomingensis

M. actinus

M. anellus

M. triorbicularis

M. ventifluminis

C. wodehousei

C. veripites
The palynostratigraphic zonation 

for the Greater Green River Basin 

is based on palynological data from 

reference samples collected from 

scattered outcrops in the eastern part 

of the basin. This biostratigraphic 

framework permits age determination 

and correlation of important coal beds 

such as those of the Deadman coal zone 

(dark bands at left).

Figure GB-3. Palynostratigraphic zones of the Fort Union Formation 

in the Greater Green River Basin.

P2

P3

P4

P5

P6

Fort Union

Formation

100 m

(upper part)

(lower part)