united states department of the interior ...k74-13-1 lowermost fort union formation, at top of a...

UNITED STATES DEPARTMENT OF THE INTERIOR

GEOLOGICAL SURVEY

STRATIGRAPHIC AND PALEOENVIRONMENT DATA FOR THE URANIUM-BEARING

LANCE AND FOX HILLS FORMATIONS, CROOK AND NORTHERN

WESTON COUNTIES, NORTHEASTERN WYOMING

By

Harry W. Dodge, Jr., and J. Dan Powell

With an Appendix on

Palynological Evaluation of some Fort Union and Lance Formation samples

from Crook and Weston Counties, Wyoming, by Bernadine D. Tschudy

Open-file report 75-502

1975

This report is preliminary and has not been edited or reviewed for conformity with U.S. Geological Survey standards and nomenclature.

Contents

Page

Introduction 1

Stratigraphy 3

Paleoenvironments- - 4

Reference 23

Appendix, by Bernadine D. Tschudy 24

Tables

Table 1. Localities where data were collected in Oshoto

15-minute quadrangle, Crook County, Wyoming,

and in northern Weston County, Wyoming 5

2. Locations of drill holes shown on electrical-log

cross section (figs. 1 and 2) in Campbell

County, Wyoming 8

3. Petrographic data from 46 thin sections of sandstones

in the Lance Formation, northeastern Wyoming 22

4. Sieve anlaysis data Sandstones in the Lance

Formation, Crook County, Wyoming - 23

List of illustration

Page

Figure 1. Index and location map-- 2-

2. Electrical log cross-section showing Lance, Fox

Hills and upper Pierre Formations in Campbell

County, Wyoming -. 9

3. Structures and textures of Lance channel sandstone

loc. K74-5-6, Crook County, Wyoming 11

4. Structures and textures of Lance channel sandstone,

loc. K74-10, Crook County, Wyoming 12

5. Structures and textures of Lance channel sandstone,

loc. K74-5-1, Crook County, Wyoming-- 13

6. . Diagram showing paleoflow directions in Lance

Formation, northern Crook County, Wyoming 14

7. Diagram showing paleoflow directions in Lance







Formation, northern Crook County, Wyoming-- 18




Formation, southern Crook County, Wyoming 20


Formation, southern Crook County, Wyoming 21ii

Plates

Page

Plate 1.--Composite stratigraphic section of Lance Formation,

Crook County, Wyoming--- In pocket

m

STRATIGRAPHIC AND PALEOENVIRONMENT DATA FOR THE URANIUM-BEARING

LANCE AND FOX HILLS FORMATIONS, CROOK AND NORTHERN

WESTON COUNTIES, NORTHEASTERN WYOMING

By Harry W. Dodge, Jr., and J. Dan Powell

Introduction

The Lance and Fox Hills Formations of latest Cretaceous (Maestrichtian)

age in Crook County, Wyoming (fig. 1), are the subjects of increasing uranium exploration activity in the eastern Powder River Basin. At this time no mining is underway, and no major discoveries of uraniun-ore concentrations have been announced. Our surface radiometric reconnaissance

showed small, low-intensity anomalies in the Lance Formation. Surface exposures show little indication of the alteration that typically accompanies roll-front uranium deposits. There is a strong indication that local

structural features and underlying petroleum deposits play a part in uranium localization.

We are studying the Lance and Fox Hills Formations in the Powder River Basin in order to determine uranium host-rock properties and their paleoenvironments. The purpose of this open-file report is to make basic data available to the public as fast as possible. Ultimately, details of

stratigraphy, sedimentology, origin, and paleoenvironments of the Lance and Fox Hills will be published as aids to uranium exploration and develop ment by private enterprise.

Geographic descriptions for all numbered localities are shown on table 1, and locations of drill holes shown on figure 2 are described in table 2. Table 3 includes petrographic data from thin section studies,

and table 4 shows weight percent of sand derived from sieve analyses.Figures 3-5 show typical stratigraphic sections of small Lance

sandstone channel, and key sedimentary parameters used in interpreting paleoenvironments. Figures 6-13 are rose diagrams depicting the strong unimodel southeast and south paleoflow directions in Lance fluvial channels. Figures 6-11 are from the northern part of the study area; figures 12-13

are from the southern part of the area.1

44°30(

MEW HAVEIM

TOWER OSHOTO

T57N

T55N

T53N

T5(N

IT49N

!05°30' R70W R66W

Figure 1.-- Index map showing Fcx Hills and Lance Formations outcrop and location ofmeasured sections and electrical log cross-sections, Crook, Weston,

and Campbell Counties, Wyoming.

Plate 1 is a composite stratigraphic section of the Lance Formation; it shows lithologic sequence and the precise stratigraphic locations of

those samples listed in tables 3 and 4, which were collected along the measured section. Data for this composite were collected by standard descriptive field techniques and were tied together by alidade and plane

table surveys. All other sample localities are listed in table 1.

Stratigraphy

Along the western flank of the Black Hills in Crook County, Wyoming (fig. 1), the last major regression of the interior Cretaceous sea is

recorded in the upward transition from Pierre Shale to Fox Hills Formation

to Lance Formation. Pierre Shale grades upward into progressively more sandy transitional strata and, finally, into light-yellowish-brown, very fine-grained slabby sandstone and silty gray shale of the Fox Hills Formation. The Fox Hills ranges in thickness from 10 to 30 m.

The youngest marine beds are Fox Hills. The Fox Hills-Lance boundary is rarely exposed, but the marine beds of the Fox Hills are

directly overlain by fluviodeltaic sandstone and mudstone of the Lance Formation. Robinson, Mapel, and Bergendahl (1964, p. 98) have used the lowest, brown carbonaceous or swelling-clay shale as the Fox Hills-Lance

contact.North and south of Crook County, the upper sandstone of the Fox

Hills is widely recognized by Robinson, Mapel, and Bergendahl (1964, p. 96)

In Crook County this upper sandstone is absent.

The Lance Formation consists of fluvial channel sandstone and interchannel mudstone and sandstone. The channel sandstones are pale-yellowish- or greenish-brown, fine-grained to very fine-grained elongate sand bodies, ranging from less than a metre to over 50 m in thickness. The interchannel sequence is composed of medium- to dark-gray, sandy clay that swells when wet, and pale-reddish-brown to gray, tuffaceous mudstones. The mudstones

commonly contain much degraded plant debris, but coal and coaly shale are conspicuously absent. Thin interchannel muddy sandstones are interlayered with the thicker mudstone units.

The Lance Formation is overlain by the Fort Union Formation of Paleocene age. The Fort Union is a sequence of fluvial sandstone and flood-plain mudstones containing coal and coaly shale. The boundary between the Lance and Fort Union Formations was picked at a conspicuous topographic break approximately 3 m below the lowest coal bed in the

Fort Union Formation.Paleoenvironments

Interpretations of field observations and the data presented in

tables 1 and 2 suggest that the Fox Hills and Lance Formations record a rapid change from nearshore marine conditions to fluviodeltaic conditions. The Fox Hills contains marine fossils at numerous localities along its

outcrop. The Lance Formation contains numerous disarticulated bones of dinosaurs and other terrestrial reptiles. In addition, a freshwater environment for all Lance rocks is strongly indicated by the palynologic

data contained in the Appendix to this report.Sedimentary structures and textural data (figs. 3, 4, and 5) indicate

a high constructive delta or coastal-plain paleoenvironment for Lance

sediments. Streams, both large and small, flowed from northwest to southeast across the western coastal plain of the interior seaway (figs. 6-13)

Our petrographic studies (table 3) suggest that Lance sediments were transported to their present location by streams flowing from uplifts in western Montana and adjacent areas to the south and southwest. Alteration of silicate minerals from primary source rocks in Montana evidently occurred mostly during transport across a coastal plain, in situ alteration of feldspars and other relatively unstable silicates in Lance rocks is not a prominent diagenetic feature.

Table 1.--Localities where data were collected in Oshoto 15-minute quadrangle, Crook County, Wyoming, and

in northern Western County, Wyoming

Loc. No. Description of locality

K74-1 Lower Lance Formation along Alkali Creek 9.7 km N. of

Oshoto, 1.6 km E. of Jewel! Oil Field, SE 1/4 sec. 7,T. 54 N., R. 67 VI., Fowler Ranch.

K74-2 Lower Lance Formation, above that of K74-1, and in same

area along east-flowing tributaries to Alkali Creekin the SW 1/4 sec. 7, T. 54 N., R. 67 W., Fowler Ranch.

K74-3 Upper part of Pierre Shale, lower Fox Hill Formation,

lowermost Lance Formation, 200 m E. of road from Oshototo New Haven (= "D" Road), in SW 1/4 NW 1/4 sec. 9,T. 54 N., R. 67 W., Fowler Ranch.

K74-4 Lower Lance Formation along Alkali Creek (downstreamfrom K74-1), 150 m south of Fowler Ranch House, incenter of NW 1/4 sec. 8, T. 54 N., R. 67 W.

K74-5 Lower Lance Formation, along Terry Draw, beginning N. ofFowler Ranch House, in NE 1/4 SE 1/4 sec. 6, T. 54 N.,R. 67 W., continuing upstream into the E 1/2, NW 1/4sec. 13, T. 54 N., R. 68 W., McKean Ranch.

K74-6 Upper part of the lower Lance Formation, along CorralCreek, in the NE 1/4 sec. 35, T. 55 N., R. 68 W.,McKean Ranch.

K74-7 Lower Lance Formation, in the upper end of Corral Creek,

in the SW 1/4 NE 1/4 sec. 14, T. 54 N., R. 68 W. McKeanRanch.

K74-8 Upper part of lower Lance Formation, along Corral Creek,in the NW 1/4 NW 1/4 sec. 11, T. 54 N., R. 68 W., McKeanRanch.

K74-9 Lower Lance Formation, north of Fowler Ranch House, inNW 1/4 sec. 5, T. 54 N., R. 67 W., north side of TerryDraw.

5

Table 1 .--Localities where data were collected continued


K74-10 Lower Lance Formation, north of Fowler Ranch House,along Terry Draw, 200 m upstream from locality K74-9,in the W 1/2 NW 1/4 sec. 5, T. 54 N., R. 67 W.

K74-11 Lower Lance Formation, in road ditch along west side ofBuffalo Creek road, about 6.4 km from its junctionwith U.S. Highway 16, in the NE 1/4 sec. 3, T. 48 N.,

R. 67 W., Weston County, Wyoming. K74-12-1 Lower Lance Formation, along Miller Creek on west side of

dirt road along the south boundary of the NW 1/4 NW 1/4

sec. 13, T. 15 N., R. 68 W. K74-12-2 Lower Lance Formation, 1.6 km N. of K74-12-1, on small

hill 80 m E. of dirt road in the SE 1/4 NE 1/4 sec. 11,T. 51 N., R. 68 W.

K74-12-3 Upper Fox Hills Formation, west side of ridge in NW 1/4NW 1/4 sec. 6, T. 51 N., R. 67 W., 150 m east of "D" road

K74-12-5 Lower Lance Formation, on south side of east-west dirtroad in SE 1/4 SW 1/4 sec. 35, T. 52 N., R. 68 W.

K74-12-7 Lower Lance Formation, along Al Creek, at stock pond atthe center of the E. line of NE 1/4 sec. 35, T. 52 N.,R. 68 W.

K74-12-8 Upper Lance Formation, S. of the Miller Creek road, very

near the extreme SE corner sec. 28, T. 52 N., R. 68 W. K74-13-1 Lowermost Fort Union Formation, at top of a small ridge

in the center of N 1/2 NE 1/4 sec. 15, T. 52 N., R. 68 W. K74-13-2 Uppermost Lance Formation, on Cabin Creek, at the center

of NE 1/4 SW 1/4 sec. 11, T. 52 N., R. 68 W. K74-13-3 Upper Lance Formation in slope south of the Little Missouri

River, in the SW 1/4 NW 1/4 sec. 26, T. 53 N., R. 68 W. K74-13-5 Lower part of upper Lance Formation, along the southwestern

end of Oshoto Reservoir, along Little Missouri River,NW 1/4 SW 1/4 sec. 18, T. 53 N., R. 67 W.

Table 1 .--Localities where data were collected continued


K74-13-7 Lower part of upper Lance Formation in N. bank of DeadmanCreek in center W 1/2 sec. 13, T. 53 N., R. 68 W.

K74-13-8 Lower part of lower Lance Formation, just N. of PrairieCreek, in SE 1/4 SE 1/4 sec. 23, T. 55 N., R. 68 W.

K74-14 Series of samples from lower part of Upper Lance Formation,in SW face of hill in center E 1/2 sec. 34, T. 55 N.,R. 68 W.

K74-15 Lowermost Lance Formation, 2 samples from 3.5 km airline,E. of Stromer, in the extreme NE corner sec. 15, T. 55 N.,R. 68 W.

K74-16-1 Lower part of Upper Lance Formation, at top of smallconical hill, in SW 1/4 NW 1/4 SE 1/4 sec. 34, T. 55 N.,R. 68 W; about 400 m SW of locality K74-14.

Table 2.--Locations of drill holes shown on electrical-log cross section (figs. 1 and 2) in Campbell County, Wyoming

1. United Western Oil & Gas Co., #12-1 Gov't.; center NE 1/4 NE 1/4,

sec. 12, T. 54 N., R. 70 W.2.--Jerry Enkich & Associates, Enkich-Gov't. #1 Norfolk; SE 1/4 NW 1/4,

sec. 11, T. 54 N., R. 71 W.

3.--Powder River Oil Co., T. G. Dorough #1 Federal; SE 1/4 SW 1/4, sec. 19, T. 54 N., R. 70 W.

4. Belco Petroleum Corp., Norfolk #1-23; NE 1/4 SW 1/4, sec. 23, T. 53 N., R. 71 W.

5. Amerada Petroleum Corp., Amerada State "G" #1; NE 1/4 NW 1/4, sec. 36, T. 53 N., R. 71 W.

6. True Oil Co., Sullivan #1-A; SW 1/4NW1/4, sec. 10, T. 52 N., R. 71 W.

7. Davis Oil Co., Johnson Federal #1; NW 1/4 NE 1/4, sec. 23, T. 52 N., R. 71 W.

8. Shell Oil Co., Gov't. #31-35; NW 1/4 NE 1/4, sec. 35, T. 52 N., R. 70 W.

9. True Oil Co., McPherson #1; SE 1/4 SE 1/4, sec. 20, T. 51 N., R. 70 W.

SOOTH

6 2.3 MILES 7 6.2 MILES 8 5 MILES 9

-400''

-20

L-JO

LANCE FORMATION

PIERRE SHALE

Figure 2. Electrical log cross section showing Lance, Fox Hills, and upper Pierre Formations in Campbell County, Wyoming. Datum is base of the Fox Hills Formation. For locations of drill holes, see figure 1.

NORTH

ro

MOO'

h-200 1

L300'

7 MILES 2 3*ILES 3 6.5 MILES

FOX HILLS

LANCE FORMATION

FORMATION

2 MILES 5

PIERRE SHALE

Figure 2.(can't.)

10

STRUCTURESAVERAGE STANDARD

GRAIN SIZE DEVIATIONTRUNCATION

SKEWnESS POINT (%)

METRES

12-

Ih

10-

9-

8

7^

-35

-30

-25

6-

5-

4-

3-

2-

-20

-15

-10

-5

(H-0

l^-rriJ^ current ripples

laminated'Interchannelmudstone

cuspate and

climbing ripples

small trough

and cuspate ripples

\

large-

scale

troughs

(festoons)

slump and channel lag,clay galls

and plant debris

Interchannel

carbonaceous

mudstone

V.V. .5 l.OY I I 1 I

\

.6 60 70 80 90

Figure 3.--Structures and textures of Lance channel sandstone, loc. K74-5-6

Crook County, Wyoming.11

STRUCTURES

METRES FEET

I-

(H-o

-25

7-

6-

5-

H5

4-

-10

-5

channel fill small troughs

nodules

*T\7 1 arge troughs

current r 1 ppl es

large

scale

troughs

(festoons)

AVERAGE STANDARDGRAIN SIZE DEVIATION

OB)' ' C0)3.0 4.0 . .5 1.0

I I I I i i i <

TRUNCATION SKEWNESS POINT

.1 0,2 .4. 70 80 90I i i i i i I

Figure 4.--Structures and textures of Lance channel sandstone, loc. K74-10,

Crook County, Wyoming.

12

STRU

CTUR

ES

MET

RES

FEET

AVERAGE

STAN

DARD

GR

AIN

SIZE

DEVIATION

3.0

4.0

0

5- -1

5

4- 3--IO

2-

0

c

-g-z

rl

Inte

rcha

nnel

E

zrrll

i-riE

lX c

arb.

m

udst

.

curr

en

t ripple

s

V

large-

scale

troughs

(festoons)

TRU

NC

ATIO

N

SKEW

NESS

PO

INT

.1

0 .2

.4

90

95i

i i

i

Figu

re 5

.--S

truc

ture

s an

d te

xtur

es of L

ance

channel sa

ndst

one,

lo

c. K7

4-5-

1,

Crook

Coun

ty,

Wyom

ing.

30 30°

60'

60 60'

303O'

LOWER LOWER LANCE N.Figure 6.--Diagram showing paleoflow directions in Lance Formation,

northern Crook County, Wyoming. Number of measurements shown in center.

14

30

60

60

3O

30°

60'

30'

MIDDLE LOWER LANCE N.Figure 7.--Diagram showing paleoflow directions in Lance Formation,

northern Crook County, Wyoming. Number of measurements shown

in center.15

30' 30°

60'

6060'

3030'

UPPER LOWER LANCE N.Figure 8, Diagram showing paleoflowdirections in Lance Formation,


in center.16

30 3O<

60

30 30'

60'

60<

LOWER UPPER LANCE N.Figure 9. Diagram showing paleoflow directions in Lance Formation,

northern Crook County, Wyoming. Number of measurements shown in center.

17

30

60

30

30°

30'

60'

6O'

MIDDLE UPPER LANCE N.

Figure 10. Diagram showing paleoflow directions in Lance Formation,


in center.

18

30

60

3O

30°

30'

60"

UPPER UPPER LANCE

Figure 11 .--Diagram showing paleoflow directions in Lance Formation, northern Crook County, Wyoming. Number of measurements shown in center.

19

30

60

30

30<

30'

LOWER LANCE S.

60'

Figure 12.--Diagram showing paleoflow directions in Lance Formation, southern Crook County, Wyoming. Number of measurements shown

in center.

20

30

60

30

30'

30'

60'

UPPER LANCE S.

Figure 13. Diagram showing paleoflow directions in Lance Formation, southern Crook County, Wyoming. Number of measurements shown in center.

21

Table 3.-Fietro9raph1c data from 46 thin sections of tandstoncs In the Lance Formation, northeastern Wyoming.

(Compositional values are expressed as percentage!. SRF - sedimentary rock fragments; «RF « netamorphtc rock fragments; VRF volcanic

rock fragments; PRF Plutonic rock fragments; leaders(-) Indicate no Information]

Loc. No. K-74-

1-3

Z-Z

4

5-1

$-3

5-6a

$-6d

5-8

7-4d

7-6

7-7-2

7-12

8

8-lc

8-2b

8-)a

8-5

8r6c

8-7e

8-BS

9e

lOe

109

lib

111

1Z-1

12-2

1Z-3

12-5

-

12-7

12-8

13-Z

13-J

13-S

13-7

13-8

14-1

14-2

14-38

14-4

14-5

14-6

14-7

15-18

15-2A

16-1

Quartz

56

37

62

54

48

49

51

52

56

57

54

58

22

32

33

25

10

26

33

40

54

60

50

61

40

60

48

58

54

70

56

40

64

51

55

40

46

64

48

56

60

51

58

55

52

70

Plaglo

Altered

3

-

2

--

-

~

»

2

3

1

4

7

2

5

1

2

-

«

-

-

«

4

~

4

--.'

-

-

6

3

2

.--

«

-

«

-

-

-

2

clase

Fresh

4

2

2

-

-

4

4

8

5

2

2

2

1

2

4

8

4

2

1

2

-

3

2

4

2

2

6

-

2

2

3

2

4

4

4

2

6

2

2

2

2

2

2

«

K-Fel

Altered

2

11

2

7

6

6

7

4

11

9

7

12

18

12

9

18

14

18

20

12

7

11

18

12

11

14

14

14

10

16

12

8

12

10

6

20

14

16

12

6

16

12

11

8

14

dspar

Fresh

3

2

1

4

6

-

-

--

"

1

2

1

2

6

6

-

4

4

6

5

2

-

6

4

3

2

2

2

-

2

4

S

«

-

6

2

2

2

2

2

4

4

Chert

11

7

7

5

5

8

3

6

4

7

7

6

6

8

11

10

2

4

4

4

8

3

«

8

2

6

-

7

4

4

2

5

4

2

8

6

2

4

4

-

6

6

*

2

4

Rock fMeta-

quartztte

3

8

1

-

6

3

5

5

2

1

2

4

3

8

9

15

4 .

2

10

6

4

~

~

-

5

4

2

-

-

2

8 .

-

2

6

8

4

4

2

8

6

8

6

4

4

2

[ I"!

SRF

14

25

17

25

13

17

21

16

12

13

14

8

26

20

17

15

5

24

22

10

8

8

14

8

20

10

6

10

12

4

10

12

12

10

3

2

6

2

8

6

14

8

8

7

12

2

pnts

HRF

-

1

5

2

10

10

4

4

3

7

7

3

6

5

2

12

4

8

4

8

4

2

4

4

2

6

2

--

2

12

6

4

4

6

3

-

6

~

6

2

4

2

2

"

VRF

-

3

-

-

4

2

1

-

"

2

5

6

4

2

-

2

-

-

-

~

2

"

-

2

-

«

-

-

-

-

-

2

6

--

~

--

-

«

2

-

6

8

"

f>RF

-

3

-

-

-

1

1

1

"

1

2

3

2

2

-

2

-

4

4

-

2

-

6

2

6

--

10

8

6

6

2

4

8

14

6

8.

6

10

3

2

2

6

8

2

Ml

Muscovite

-

1

1

-

--

-

2

--

1

2

2

2

-

1

1

2

~

-

-

2

2

-

-

1

1

-

«

-

-

3

~

~

«

2

2

«

1

--

1

-

--

1

-

-

as

Biottte

1

-

-

2

2

~

-

-

1

3

1

2

2

1

1

4

3

3

3

2

6

-

2

2

1

~

1

-

-

-

ri2

2

-

1

-

-

1

--

--

-

"

Average maximum grain size ( »)

.....

0.145

0.170

.....

0.195

0.118

0.155

0.112

0.175

0.190

0.270

0.300

0.380

.....

0.137

0.182

0.130

0.130

0.138

0.125

0.081

0.177

.....

0.160

0.100

0.140

0.130

0.170

0.142 .

0.140

0.163

0.147

0.177

0.188

0.133

0.167

0.140

0.142

0.124

0.096

0.121

0.153

0.073

Sorting

"I*

._..

0.467

0.511

.....

0.592

0.656

0.744

0.579

0.711

0.587

0.820

0.567

1.004

.....

0.802

0.873

0.987

0.554

0.539

0.529

0.883

0.411

.....

0.910

0.600

0.480

0.410

0.765

0.444

0.520

0.364

0.470

0.340

0.540

0.550

0.780

0.540

0.770

0.800

1.080

0.445

0.780

1.11

Remarks

+3 percent interstitial clay.

Trace fresh hornblende.

4 percent authtgentc chlortte in

cement.

1 percent heavy minerals.

Chlortttzed rock fragments.

Plagtoclase very large (0.4 mi).

1 percent hornblende, plagtoclase

very fresh.

1 percent organic grains;

dumorttertte.

1 percent FeO grains; altered btotfte.

1 percent heavy ntnerals.

Heavy outcrop weathering.

Possibly freshwater algal structures.

6 percent.

Trace fresh hornblende; saussertttzed

feldspar.

Sausserlttzed feldspars.

FeO * calclte-cemented nodule (algalT).

Carbonate nodule (algal?).

Biottte altered to Itrontte.

Zoned feldspar. Chlortttzed volca'ntc

rock fragments; hornblende 2 percett

Btotlte altered to llmontte, weathered

Biottte altered to llnonlte. weathered

Biottte altered to Itirontte. weathered

Btotlte altered to llmonlte, weathered

Terrt9. clay In matrix (5 percent).

2 percent hematite grains.

Much composite stained quartz. "

Rounded feldspar.

Minor chalcedonlc cement.

Plutonic rock fragments altered;

20 percent elongate quirt/.

20 percent elongate quartz.

Much angular quartz.

Ntnor clay Mtrix.

Minor clay Mtrix..

Angular and round feldspars.

Fresh, angular mtcrocUne.

1 percent fresh hornblende.

1 percent heavy ntnerals.

Mtnor clay natrtx.

Large twinned Kspar; pcrtMte.

Mtnor clay Mtrix.

Large, elongate chert.

5 percent clay Mtrix..

Fresh plutontc rock fragments.

porphyry.

Fresh plutonlc rock fragments and

hornblende.

Very fine grained, no clay.

Table4 .--Sieve analysis data Sandstones In the lance Fonnatlon.

Crook County, Wyoming

Sample No. -0.5

K74-2a

K74-2b

K74-2C 0.02

K74-2d

K74-2-1

K74-3

K74-5-la

K74-5-lb

K74-5-1C

K74-5-3a

K74-5-3b

K74-5-5b

K74-5-6a

K74-5-6b

K74-5-6C

K74-5-6d

K74-5-6e

K74-5-7

K74-7-5

K74-7-7-1

K74-7-8

K74-8-7b

K74-8-83

K74-9a

K74-9b

K74-9c

K74-9d

K74-103

K74-10b

K74-10C

K74-10d

K74-11

K74-lld

K74-lle

K74-llf

K74-llh

K74-F

Weight -percent

0 0.5 1.

0.

0.01 0.01 0.

0.06 0.05 0.

0.01 0.

0.02 0.03 ,0.

0.

0.01 0.

0.

0.

0.

0.03 0.

0.01 0.

0.02 0.

0.03 0.

0.01 0.

0.01 0.

0.

0.

0.

0.01 0.

0.01 0.01 0.

0.

0.

0.

0.

0.

0.

0.08 0.04 0.

o.0.04 0.

0.05 0.

0.01 0.

0.02 0.

0.01 0.

0

04

02

09

03

04

20

03

01

01

01

11

07

04

10

02

02

01

06

11

07

08

01

02

01

04

02

01

03

01

91

73

01

08

02

1.5

0.3

0.4

1.1

0.28

1.1

0.04

1.81

0.08

0.11

0.01

0.14

0.48

0.53

0.41

0.49

0.10

0.24

0.03

0.28

0.58

3.05

1.79

0.08

0.51

0.08

0.03

0.06

0.08

0.03

0.04

1.15

7.2'3

4.13

4.90

0.08

0.11

sand held on sieve size ($)

2.0

2.0

15.1

26.9

4.95

27.9

0.01

0.45

5.67

0.29

1.27

0.08

12.52

5.53

4.55 .

4.02

1.32

1.00

6.68

0.37

7.22

2.12

36.00

21.38

2.50

7.31

1.82

0.62

3.44

4.08

1.25

1.35

1.66

11.96

6.69

6.82

4.63

0.54

2.5

13.2

41.0

40.9

30.90

46.7

0'.22

9.93

10.94

6.38

24.18

2.45

60.68

30.49

26.17

34.93

9.63

1.55

26.61

11.29

18.76

7.78

41.72

40.72

25.97

24.81

25.10

10.99

19.66

31.19

9.76

9.41

15.91

27.90

23.68

20.67

4.83

1.84

3.

59.

33.

24.

48.

18.

3.

55.

43.

39.

43.

28.

12.

44.

49.

40.

37.

3.

30.

55.

49.

21.

12.

26.

50.

50.

49.

42.

51.

52.

26.

19.

38.

28.

32.

44.

8.

9.

0

6

8

2

24

6

36

79

3

80

68

56

33

92

43

93

94

93

57

09

36

92

61

49

30

56

82

70

19

23

11

02

57

74

54

45

93

27

3.5

20.1

6.6

4.4

12.07

3.7

37.31

25.18

30.22

34.98

22.39

40.2

5.57

13.17

15.19

14.89

33.54

20.67

22.76

26.59

18.28

39.78

3.11

4.01

14.23

11.83

16.43

33.13

17.28

7.66

37.19

35.00

26.64

11.15

13.82

15.84

37.73

64.77

4.0

2.0

1.1

0.1

1.72

0.8

36.00

4.68

5.20

9.09

3.33

11.37

2.59

2.04

1.91

2.19

7.73

33.16

6.16

4.21

6.60

15.58

0.84

0.95

2.83

2.18

3.15

8.12

3.28

1.81

10.76

14.65

5.61

3.80

4.92

2.39

20.55

9.64

4.5- 8.0

2.08

1.18

0.87

1.35

0.80

19.93

2.46

2.15

7.45

2.82

11.19

3.58

2.28

1.61

1.73

6.20

35.48

5.23

1.75

2.12

9.53

0.86

2.47

2.09

1.87

2.77

2.98

3.92

2.12

11.21

16.80

6.37

4.15

7.71

3.18

17.69

8.33

>8.0

0.52

0.67

0.43

0.43

0.39

3.15

0.87

0.49

0.69

2.19

6.14

2.59

0.96

0.55

0.84

3.02

4.09

1.71

0.65

1.32

2.60

1.69

2.08

1.18

0.91

0.82

1.42

1.13

0.80

3.68

3.57

4.09

4.12

5.72

1.72

5.47

5.48

23

ReferenceRobinson, C. S., Mapel, W. J., and Bergendahl. M. H., 1964, Stratigraphy

and structure of the northern and western flanks of the Black Hills uplift, Wyoming, Montana, and South Dakota: U.S. Geol. Survey Prof. Paper 404, 134 p.

24

Appendix

Palynological evaluation of some Fort Union and Lance Formation samples from Crook and Weston Counties, Wyoming

By

Bernadine D. Tschudy

Seven samples were submitted for palynological evaluation. All were

productive and were given USGS paleobotany locality numbers as follows:

Sample No.

K74-1

K74-2

K74-5a

K74-7-16

K74-10f

K74-10H

K74-llg

Locality

SE 1/4 sec. 7, T. 54 N., R. 67 W., Crook County, Wyo.SW 1/4 sec. 7, T. 54 N., R. 67 W. D5191 Crook County, Wyo.SE 1/4 sec. 1, T. 54 N., R. 68 W., D5192 Crook County, Wyo.NW 1/4 sec. 16, T. 54 N., R. 68 W., D5193 Crook County, Wyo.NW 1/4 sec. 5, T. 54 N., R. 67 W., Crook County, Wyo.NW 1/4 sec. 5, T. 54 N., R. 67 W., Crook County, Wyo.

USGS paleobotany loc. no.______

D5190

C sec. 3, T. 48 N., R. 67 W., Weston County, Wyo.

D5194-A

D5194-B

D5195

25

The

spec

imen

s identified f

rom

thes

e seven

samples

are

show

n be

low:

PO en

Formation

Sample N

o.USGS p

aleo

loc.

no

.Ta

xa:

Deltoi

Cyat

hidi

tes

Laevigatos

cf.

0-p2

6Sl-sm

6Li

liac

idit

esArecipites

Ovoi

dite

s L

Schi

zosp

ori

Kurt

zipi

tes

Tric

olpi

tes

Tricolp

ites

Ang

ulol

C3

syn-

sm

Fort

U

nion

. K

74-7

-16

obot

any D

5193

pora

X

es

X

sporite

s X

6 X X

tes

X

s C

olum

ellu

s X

Lign

eolu

s X

ris

Par

vus

X

es

X

es

Hia

ns

X

es

X

umin

osus

i X

ite

s

X

Subtr

iangula

X

L.u

wcr

uuw

cr

i_u

wcr

L.

UW

CI

L.U

WC

I L.

UW

CI

Lanc

e La

nce

Lanc

e La

nce

Lanc

e La

nce

K74

-1

K74

-2

K74

-5a

K7

4-1

0f

K74

-10h

K

74-llg

D

5190

D

5191

D

5192

D

5194

-A

D51

94-IB

D

5195

XX

X

X

X X

. X

X X

X X

X

XX

X

X

XX

X

XX

X

X X

XX

X

The

specimens

identified f

rom

thes

e seven

samples

are

show

n below:--Continued

ro

Formation Lower

Fort

Union

Sample N

o. K74-7-16

USGS pa

leob

otan

y

D

5193

loc. no.

Taxa

:P3-sm

P3-r

t plus P3-r

Alni

poll

enit

esUlmipollenites

cf L

ecaniella

cf N

eves

ispo

rite

sOs

mund

acid

ites

Lept

olep

idit

esSt

erei

spor

ites

Glei

chen

iidi

tes

Poly

cing

ulat

ispo

rite

sBa

lmei

sppr

ites

TT -

sm

TC-sm

& TO-sm

Low

er

Lanc

e

K74

-1

D51

90

Low

er

Lanc

e

K74

-2

D51

91

Low

er

Lanc

e

K74

-5a

D51

92

Low

er

Lanc

e

K74-1

0f

D51

94-A

Low

er

Lanc

e

K74

-10h

D

5194

-B

Low

er

Lanc

e

K7

4-llg

D

5195

X X X

X X X

X X

X X X

The

specimens

identified f

rom

thes

e se

ven

samp

les

are

show

n be

low:--Continued

ro 00

Formation Lower

Fort

Un

ion

Samp

le No. K74-7-16

USGS pa

leob

otan

y D5193

Toe. no.

Taxa

:Li

liac

idit

es dividuus

Sl-s

mAbietineapollenites

Aquilapollenites

Quadri

lobus

Aquilapollenites

Attenu

atus

cf A

quilapollenites

Argutus

Aquilapo

llen

ites

Delica

tus

Prot

eaci

dite

s Er

dtma

nipo

llis

cf Z

livi

spor

is

Kuylisporites

TO-r

t &

TT-P

Lili

acid

ites

complexus

Lower

Lance

K74-

1 D5

190

X X X X X X X X X

Lower

Lance

K74-2

D5191

X X X X X X X

Lowe

r Lance

K74-5a

D5192

X X X X X X X X X

Lower

Lowe

r Lance

Lanc

e

K74-

10f

K74-

10h

D519

4-A

D519

4-B

X

X X

X X

X X X

X X

X

Lower

Lanc

e

K74-

llg

D5195 X X X X X X X X

The

specimen

s identified f

rom

these

seven

samp

les

are

shown

belo

w: C

onti

nued

Formation ---

Samp

le No.

USGS p

aleobotany

loc. no.

Taxa:

Inaperturotetradi tes

cf I.

Sc

abra

tus

Tricolpites

reti

cula

tus

Cran

well

ia

[g

Wode

hous

eia

Taxodi aceaepol1eni te

s Aquilapollen

ites

reticulatus

Aquilapollen

ites

Cate

nireticula

tus

cf

C3P

-13

cf P

ulch

erip

olle

nite

s Azolla m

assu

la

Undulatispor

ites

Hann

ispo

ris

TO-sm

29

cf L

ycopodiumsporites

Facetus

Lower

Fort

Unio

n K

74-7

-16

Lowe

r Lance

K74-

1

Lower

Lance

K74-2

Lowe

r Lance

K74-5a

X X X X X X X X X

X X X X X X X X X X

Lower

Lance

K74-

10f

Lowe

r Lance

K74-10h

Lowe

r La

nce

K74-

llg

The

spec

imen

s identified f

rom

these

seve

n sa

mple

s ar

e shown

belo

w:--

Cont

inue

d

CO o

Formation- Lower

Fort

Unio

nSample No. K74-7-16

USGS p

aleo

bota

ny

D5193

loc.

no.

Taxa

:TC

-sm

4Aquilapollenites senonicus

Aqui

1apo

l1en

ites

be

rti1

1oni

tes

Aqui

lapo

llen

ites

reductus

Aqui

lapo

llen

ites

con

atus

Low

er

Low

er

Lanc

e La

nce

K74

-1

K74

-2

D51

90

D51

91

Low

er

Lanc

e

K74

-5a

D51

92 X X X X X

Low

er

Low

er

Low

er

Lanc

e La

nce

'Lan

ce

K74-1

0f

K74

-10h

K

74

-llg

D

5194

-A

D51

94-B

D

5195

X

united states department of the interior ...k74-13-1 lowermost fort union formation, at top of a...

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