COW CANYON

EASTERN ARIZONA

Since the original survey of this source in the mid-1980s, I've re-visited the primary domes and surveyed to the west toward Eagle Creek, and the east toward the Blue River multiple times.  As noted below, the primary highly eroded dome complex at the upper end of Cow Canyon is on a divide where some of the source obsidian erodes west into Eagle Creek and then into the Gila River, and some erodes east toward the Blue River, on into the San Francisco River, and then the Gila River (see map here; Shackley 2016).  The text below describes the evolution of the knowledge of the source from the mid-1980s until 2016.  The source was first noticed by Glen Rice (Arizona State University) while engaged in his Ph.D. dissertation fieldwork in the Blue River region.

From Shackley (1988, 1989). Sections 2 and 3 R29E, T2S, USGS Pipestem Mtn 7.5' Quad, Apache National Forest, central Greenlee County, Arizona. This is a relatively small source along and east of Arizona Hwy 666 [now 191] located in a Neogene rhyolite body. There is some suggestion that this too is a Tertiary rhyolite body remnant surrounded by the Quaternary basalt, but this was difficult to determine for this study. The nodules are found within an eroded rhyolite/ash unit that appears to be a remnant dome structure. Perlite or vitrophyre was not evident. The nodules are common in a rhyolite regolith on top of the dome as well as the rhyolite/ash alluvium at the base of the slopes. Nodules up to 5 cm in diameter are available, but most of the nodules are near or less than 4 cm. The density of nodules is fairly high in places, up to 5 per m2. Cortex is mainly a thin gray-black often with a velvet-like character. The interior glass is aphyric and the color is as variable as many of the mid-Tertiary marekanite sources. The most common color/opacity is a near transparent brown-green sometimes with thin banding. A few specimens exhibit a nearly opaque aphyric gray-green banded megascopic character.  The nodules are eroding and funneled into the Cow Canyon Creek/Turkey Creek system possibly reaching the Blue River 15 km east. Reduced nodules and flakes occur everywhere on the regolith and in the alluvium. The pattern of reduction is similar to Vulture with sporadic bipolar reduction throughout the source area. Overall the rejected core/flake density is less than 1 per 5m2. There are no published sources on this locality other than the county geology map (Wilson and Moore 1958).

[updated 1995] It appears that the secondary depositional extent of this source is much greater than originally mapped (Shackley 1988). This Tertiary source is eroding east into the Blue River, south into the San Francisco River and west into the Gila River as originally noted, but also erodes in much higher density west into Eagle Creek west of the Blue River, and on south into the Gila River and up to 20 km south into the San Simon River Valley. A number of “pockets” of Cow Canyon glass have been located in the San Simon River Valley in Pliocene/Pleistocene sediments the result of considerably higher sedimentation rates in these periods than currently. The density of nodules at Eagle Creek approximately 15 km west of the primary contexts at Cow Canyon is up to 1 per 10m2, and less than 100 times lower in the Gila River (Shackley 1995). Again, these nodules are mixed with the Mule Creek marekanites in the alluvium.

The 111 Ranch Formation.  In the mid-1990s while conducting field schools in the San Simon River Valley, Pat Gilman (University of Oklahoma) identified some marekanites up to 50 mm in diameter eroding out of the 111 Ranch Formation, a Pliocene lacustrine sedimentary formation in the San Simon Valley (see map here).  These lacustrine sediments dating between 2.17 and 2.67 Ma were formed when the ancestral Gila River was dammed downstream and created a shallow lake in the basin, most recently mapped by Houser et al. (1985).  The sediments are often gypsiferous and marekanites often exhibit calcium carbonate on the exterior (see images here).  What is unique in the 111 Ranch Formation is that while the elemental concentrations overlap the Cow Canyon primary source and secondary deposits above Eagle Creek on Robinson Mesa upstream, the Sr and Ba concentrations are often a bit lower, and the nodule sizes are larger, up to 50 mm not seen in the Cow Canyon secondary deposit nodules in San Francisco and Gila River alluvium, although up to that size at the Cow Canyon dome complex (see images and map here).  It does appear that the "source" for the 111 Ranch marekanites is in the Robinson Mesa area above Eagle Creek upstream, and the event that created the lake in the basin was likely a very large fluvial event (see elemental analysis discussion below).  At the Murray Springs Clovis levels, all the obsidian artifacts including two Clovis points were produced from the higher Sr Cow Canyon obsidian, so the raw material was likely procured near or at the primary domes, although this is impossible to verify (Shackley 2008, see also Shackley 1989).

 

Compositional XRF Analysis, 2016.  In order to better understand the relationship between the Cow Canyon Dome Complex obsidian and that recovered from the 111 Ranch Formation the original mid-1980s samples, samples collected in the 1990s, and the 111 Ranch Formation samples collected in the 1990s were analyzed or re-analyzed (see accompanying tables and plots).  As mentioned above, while the 111 Ranch Formation obsidian generally exhibits lower Sr and Ba concentrations, there is considerable overlap between 111 Ranch and the primary domes and particularly the secondary deposit obsidian on Robinson Mesa and along Eagle Creek, west of the primary domes (see data and plots here).  Given this, I suggest that the source(s) be called Cow Canyon or Cow Canyon/111 Ranch, the former would be most correct since it does appear that the origin is upstream somewhere in the Cow Canyon to Robinson Mesa area.

Digital elevation model of the location of the collection localities analyzed including the Cow Canyon Dome Complex and the 111 Ranch Formation.

 

Mean and central tendency for the Cow Canyon source standard elemental concentrations.

Elemental concentrations for the source standards by locality and USGS RGM-1 rhyolite standard.

Sample

Source Loc.

Ti

Mn

Fe

Zn

Rb

Sr

Y

Zr

Nb

Ba

Pb

Th

111-4

111 Ranch Form.

1075

400

8266

45

143

86

22

87

13

1062

22

15

111-5

111 Ranch Form.

1061

424

8269

37

149

86

25

87

20

985

21

18

111-14

111 Ranch Form.

1048

423

8224

59

141

82

24

90

19

1196

22

21

111-2

111 Ranch Form.

1144

420

8733

60

142

87

27

89

19

1230

20

14

111-10

111 Ranch Form.

1074

459

8550

52

153

89

23

93

25

1180

25

20

111-3

111 Ranch Form.

1133

452

8298

46

153

90

23

88

13

1107

18

18

111-12

111 Ranch Form.

1343

578

10037

61

174

101

24

97

18

1210

27

6

111-1

111 Ranch Form.

1070

457

8380

44

152

89

25

90

18

1128

21

13

111-6

111 Ranch Form.

1021

389

7918

150

136

80

24

82

20

986

20

10

111-13

111 Ranch Form.

1153

466

8667

46

157

86

24

101

18

1114

20

14

111-7

111 Ranch Form.

1106

445

8707

54

142

84

27

91

16

1222

20

6

111-8

111 Ranch Form.

1170

461

9274

60

134

113

31

138

24

949

18

14

SV-9

111 Ranch Form.

1065

418

8208

93

143

88

23

91

20

1208

18

15

SV-1

111 Ranch Form.

1124

421

8515

72

142

87

25

85

15

1114

22

15

SV-2

111 Ranch Form.

1061

442

8304

53

152

91

22

86

18

1261

23

17

SV-3

111 Ranch Form.

1130

432

8875

57

125

104

24

130

19

956

16

4

SV-6

111 Ranch Form.

1119

419

8374

95

144

85

22

87

18

1134

23

11

SV-4

111 Ranch Form.

1069

400

8380

88

147

86

21

87

21

1164

18

13

SV-5

111 Ranch Form.

1206

405

8532

63

147

86

22

86

16

1172

20

17

SV-6-1

111 Ranch Form.

1286

486

9599

83

138

110

25

140

19

1006

24

9

SV-8

111 Ranch Form.

1090

426

8249

75

147

79

19

89

18

1141

18

17

SV-7

111 Ranch Form.

1002

443

8380

54

149

79

22

88

15

1124

23

11

060494-1-A

Cow Canyon Prim.

1211

496

9684

52

142

112

22

142

21

996

24

5

060494-1-B

Cow Canyon Prim.

1285

511

10001

57

145

114

25

145

22

970

20

17

060494-1-C

Cow Canyon Prim.

1332

526

9965

53

154

120

23

151

17

1130

21

12

CC-18

Cow Canyon Prim.

1196

447

9421

51

136

112

26

136

24

965

18

17

CC-17

Cow Canyon Prim.

1289

488

9968

56

148

117

25

142

22

965

22

15

CC-8

Cow Canyon Prim.

1258

490

9881

56

149

117

21

141

19

942

18

20

CC-4

Cow Canyon Prim.

1221

510

9710

56

152

103

26

131

15

987

20

18

CC-20

Cow Canyon Prim.

1243

457

9620

54

136

110

26

138

17

937

16

4

CC-21

Cow Canyon Prim.

1192

460

9642

55

136

113

27

136

16

776

19

8

CC-1

Cow Canyon Prim.

1105

432

8288

45

148

87

25

94

20

965

18

16

CC-5

Cow Canyon Prim.

1217

473

9474

45

138

112

22

131

17

853

23

9

CC-19

Cow Canyon Prim.

1249

470

9627

55

136

113

23

136

26

899

19

12

CC-7

Cow Canyon Prim.

1282

544

10041

62

147

115

25

138

17

911

19

23

CC-11

Cow Canyon Prim.

1344

509

10006

54

148

120

25

143

26

1015

17

12

CC-16

Cow Canyon Prim.

1147

506

9815

54

142

116

26

137

19

1026

20

15

CC-10

Cow Canyon Prim.

1152

472

9340

46

132

112

27

133

15

925

19

13

CC-3

Cow Canyon Prim.

1313

508

9807

52

146

120

24

140

17

1040

20

24

CC-9

Cow Canyon Prim.

1218

476

9376

47

135

108

26

128

18

874

16

22

CC-6

Cow Canyon Prim.

1146

489

9451

52

141

111

27

135

18

972

24

9

CC-14

Cow Canyon Prim.

1318

552

10504

56

151

120

25

147

19

1036

26

17

CC-13

Cow Canyon Prim.

1370

599

10934

69

164

121

28

147

22

1049

22

13

CC-12

Cow Canyon Prim.

1179

477

9664

52

142

116

24

134

20

830

24

16

061016-2-1

Cow Canyon Prim.

1114

485

9211

81

163

36

27

95

20

322

21

17

060494-1-D

Cow Canyon Prim.

1321

517

9874

59

146

122

24

137

23

899

20

20

060494-1-E

Cow Canyon Prim.

1330

476

9880

56

135

111

28

135

23

911

16

13

060494-1-F

Cow Canyon Prim.

1158

393

9092

46

134

127

20

127

10

1459

18

9

060494-1-24

Cow Canyon Prim.

1272

454

9550

71

141

106

26

131

15

975

20

4

060494-1-11

Cow Canyon Prim.

1229

448

9352

58

136

110

25

137

19

1061

17

16

060494-1-10

Cow Canyon Prim.

1240

460

9471

57

138

118

25

137

16

1061

19

21

060494-1-12

Cow Canyon Prim.

1249

503

9644

71

143

116

27

135

21

923

21

23

060494-1-14

Cow Canyon Prim.

1176

455

9270

53

141

116

25

136

20

1039

19

12

060494-1-22

Cow Canyon Prim.

1214

468

9354

64

140

105

27

131

24

957

23

4

060494-1-15

Cow Canyon Prim.

1174

493

9611

66

143

112

27

137

19

1043

18

16

060494-1-13

Cow Canyon Prim.

1236

485

9393

58

144

108

23

136

15

1014

17

11

060494-1-17

Cow Canyon Prim.

1186

492

9615

51

138

115

23

137

18

1028

20

10

060494-1-20

Cow Canyon Prim.

1153

477

9474

58

140

114

24

130

16

1010

19

16

060494-1-21

Cow Canyon Prim.

1191

483

9390

60

146

109

22

129

22

876

21

19

060494-1-19

Cow Canyon Prim.

1140

457

9290

50

142

116

22

134

15

979

21

5

060494-1-23

Cow Canyon Prim.

1269

463

9564

64

137

115

25

138

24

924

19

14

060494-1-16

Cow Canyon Prim.

1311

507

9741

80

145

107

24

130

19

881

21

16

060494-1-18

Cow Canyon Prim.

1203

531

9520

65

134

113

25

135

19

1042

15

10

061093-1-9

Eagle Cr/Bee Can. Quad

1139

510

9570

54

137

105

24

134

22

978

22

10

061093-1-6

Eagle Cr/Bee Can. Quad

1233

485

9852

53

149

112

25

134

18

861

18

6

061093-1-10

Eagle Cr/Bee Can. Quad

915

583

7919

55

209

12

35

79

33

0

25

14

061093-1-2

Eagle Cr/Bee Can. Quad

1227

509

9484

54

138

117

26

137

17

949

22

21

061093-1-4

Eagle Cr/Bee Can. Quad

1237

454

9300

49

157

118

23

110

16

1439

24

22

061093-1-11

Eagle Cr/Bee Can. Quad

1102

431

8451

39

144

107

25

101

16

1221

18

10

061093-1-8

Eagle Cr/Bee Can. Quad

1256

420

9100

50

154

114

21

100

20

1214

21

18

061093-1-12

Eagle Cr/Bee Can. Quad

1140

444

9065

52

137

111

22

125

18

966

19

10

061093-1-1

Eagle Cr/Bee Can. Quad

1157

433

8805

49

136

104

21

101

18

1271

20

23

060394-1-1

Eagle Cr/Robinson Mesa

1176

394

8873

44

143

103

19

98

17

1326

19

16

060394-1-2

Eagle Cr/Robinson Mesa

1285

492

9706

59

145

114

26

138

14

980

27

15

060394-1-3

Eagle Cr/Robinson Mesa

1186

486

9704

76

140

105

22

129

23

959

23

9

060494-1-8

Eagle Cr/Robinson Mesa

1097

404

8794

69

139

104

22

96

13

1273

14

9

RGM1-S4

USGS standard

1523

296

13251

41

151

109

24

217

13

811

21

14

 

            

 

Sr, Rb, Zr three-dimensional plot of source standards from the localities (left), and Ba, Zr bivariate plot of the same samples.  Note generally lower Sr and Ba in the 111 Ranch samples, but elemental overlap between all localities.

 

References Cited 

Houser, B.B., D.H. Richter, and M. Shafiqullah, 1985, Geologic map of the Safford Quadrangle, Graham County, Arizona.  USGS Miscellaneous Investigation Series Map 1-1617.   

Shackley, M.S., 1988, Sources of archaeological obsidian in the Southwest: an archaeological, petrological, and geochemical Study.  American Antiquity 53:752-772. 

Shackley, M.S., 1989, Early hunter-gatherer procurement ranges in the Southwest: evidence from obsidian geochemistry and lithic technology. Ph.D. dissertation, Department of Anthropology, Arizona State University. 

Shackley, M.S., 1995, Sources of archaeological obsidian in the greater American Southwest: an update and quantitative analysis.  American Antiquity 60:531-551. 

Shackley, M.S., 2008, Source provenance of obsidian artifacts from the Murray Springs Clovis     Site, southern Arizona.  Report prepared for C. Vance Haynes, Department of Anthropology, University of Arizona. 

Wilson, E.D., and R.T. Moore, 1958  Geologic map of Graham and Greenlee Counties, Arizona. Arizona Bureau of Mines, University of Arizona.

This page maintained by Steve Shackley (shackley@berkeley.edu).
Copyright 2016 M. Steven Shackley. All rights reserved.
Revised: 04 July 2016

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