Element Concentrations in Surface Soils of the Coconino 

Plateau, Grand Canyon Region, Coconino County, Arizona

By Bradley S. Van Gosen

Open-File Report 2016–1160

U.S. Department of the Interior

U.S. Geological Survey
ii

U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Director

U.S. Geological Survey, Reston, Virginia: 2016 

For more information on the USGS—the Federal source for science about the Earth,

its natural and living resources, natural hazards, and the environment—visit 

http://www.usgs.gov or call 1–888–ASK–USGS (1-888-275-8747).

For an overview of USGS information products, including maps, imagery, and publications,

visit http://store.usgs.gov.

Any use of trade, firm, or product names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.

Although this information product, for the most part, is in the public domain, it also may 

contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items 

must be secured from the copyright owner.

Suggested citation: 

Van Gosen, B.S., 2016, Element concentrations in surface soils of the Coconino Plateau, Grand Canyon region, 

Coconino County, Arizona: U.S. Geological Survey Open-File Report 2016–1160, 9 p. 

http://dx.doi.org/10.3133/ofr20161160. 

ISSN 2331-1258 (online) 
iii

Contents

Acknowledgments ......................................................................................................................................... v

Abstract ......................................................................................................................................................... 1

Introduction.................................................................................................................................................... 1

Background................................................................................................................................................ 2

Sample Collection.......................................................................................................................................... 5 

Sample Preparation ................................................................................................................................... 5 

Analytical Techniques ................................................................................................................................ 5

Summary of Results ...................................................................................................................................... 5

References Cited........................................................................................................................................... 7

Appendix 1. Geochemical Analyses of Soils Collected on the Surface of the Coconino Plateau

Grand Canyon Region, Northern Arizona...................................................................................................... 9

Figures

1. Index map for background soil samples collected from the surface of Coconino Plateau ................ 3

2. Aerial view of the SBF breccia pipe showing the locations of background soil samples collected 

at this feature in 1985 ....................................................................................................................... 4 

Table

1. Summary statistics of geochemical analyses of soils collected on the surface of the 

Coconino Plateau ............................................................................................................................. 6 
iv

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

Mass

pound, avoirdupois (lb) 0.4536 kilogram (kg)

Horizontal coordinate information is referenced to the North American Datum of 1927 (NAD 1927).
v

Acknowledgments

The 1984–1986 soil sampling survey was conducted by the U.S. Geological Survey as part of a larger project funded 

by the Bureau of Indian Affairs in cooperation with the Hualapai Indian tribe. Karen Wenrich, U.S. Geological Survey

Research Geologist, was the project lead for the large encompassing research project that evaluated the potential for 

uranium-bearing breccia pipe deposits in the Hualapai Indian Reservation and northern Arizona in general. Joseph 

Mascarenas, Betsi Esposito, Nancy Parduhn, and Mary Hendricks assisted in the collection of the soil samples. 

William L. Thoen assisted in the computer retrieval, manipulation, and organization of the analytical data. The 

geochemical data were determined by the following analysts at the U.S. Geological Survey laboratory: Paul H. Briggs, 

James R. Budahn, Jeff Cornell, James G. Crock, David E. Detra, David Fey, D. Brooke Hatfield, Susan D. 

Hollingsworth, Kay Kennedy, Larry R. Layman, Fred E. Lichte, Johnny McDade, David M. McKown, Vie Merrit, James 

L. Seeley, Kathleen Stewart, Josepth E. Taggart, Robert B. Vaughn, and Stephen A.Wilson.
Element Concentrations in Surface Soils of the Coconino 

Plateau, Grand Canyon Region, Coconino County, Arizona

By Bradley S. Van Gosen

Abstract

This report provides the geochemical analyses of a large set of background soils collected from

the surface of the Coconino Plateau in northern Arizona. More than 700 soil samples were collected at 

46 widespread areas, sampled from sites that appear unaffected by mineralization and (or) 

anthropogenic contamination. The soils were analyzed for 47 elements, thereby providing data on metal 

concentrations in soils representative of the plateau. These background concentrations can be used, for 

instance, for comparison to metal concentrations found in soils potentially affected by natural and 

anthropogenic influences on the Coconino Plateau in the Grand Canyon region of Arizona. 

The soil sampling survey revealed low concentrations for the metals most commonly of 

environmental concern, such as arsenic, cobalt, chromium, copper, mercury, manganese, molybdenum, 

lead, uranium, vanadium, and zinc. For example, the median concentrations of the metals in soils of the 

Coconino Plateau were found to be comparable to the mean values previously reported for soils of the 

western United States.

Introduction

This report provides geochemical analyses of more than 700 background soil samples collected 

in 1984, 1985, and 1986 by the U.S. Geological Survey (USGS) at 46 widely separated areas on the 

surface of the Coconino Plateau, south of the Grand Canyon in northern Arizona. Analytical results for 

47 elements in these soils are provided in the accompanying spreadsheet “Geochemical Analyses of 

Soils Collected on the Surface of the Coconino Plateau, Grand Canyon Region, Northern Arizona” (see 

appendix 1). A statistical summary of the analytical results is provided to represent the chemistry of 

soils at the surface of the Coconino Plateau, specifically, a large set of representative soils that appear 

unaffected by mineralization and (or) anthropogenic contamination. 

The accompanying dataset can be used to represent the elemental concentrations typical of soils 

of the Coconino Plateau (“background values” 1) for comparison to other soils that may have been 

altered by anthropogenic activities or natural influences. For example, the geochemistry of background 

soils provided in this report can be compared to the concentrations in soils near uranium mining 

operations in this region (Alpine, 2010; Bills and others, 2011; Bureau of Land Management, 2011; 

Naftz and Walton-Day, 2016). 

 

1

In this context, geochemical “background” is used to describe “a relative measure to distinguish 

between natural element or compound concentrations and anthropogenically-influenced concentrations 

in real sample collectives,” as discussed by Matschllat and others (2000, p. 991). 
2

Background

In 1984, 1985, and 1986, the USGS conducted a soil sampling survey across numerous solutioncollapse features exposed on the surface of the Coconino Plateau, south of the Grand Canyon in 

northern Arizona (Van Gosen and Wenrich, 1991). These features were selected for the soil survey 

because they were thought to typify the outcrop manifestation of sedimentary solution-collapse features 

in the Grand Canyon region, which can include 

• deeply rooted, solution-collapse breccia pipes that sometimes contain significant deposits of 

uranium and base metals (Wenrich, 1985, 1986; Chenoweth, 1986, 1988; Wenrich and others, 

1989b; Alpine, 2010; Ross and Moreton, 2012); 

• shallow collapse features formed by dissolution of underlying beds of gypsum (“gypsum 

collapses”); and

• shallow sinkholes. 

The soil surveys were conducted across the surface of the following types of features exposed on 

the surface of the Coconino Plateau (fig. 1): (a) 3 solution-collapse breccia pipes known to contain 

substantial uranium and base-metal mineralization at depth—the Canyon, “SBF,” and Mohawk Canyon 

breccia pipes; (b) 1 feature interpreted to overlie a “gypsum collapse”; (c) 1 feature interpreted to be a 

sinkhole; (d) 37 circular features that may overlie breccia pipes, which were identified and mapped by 

Wenrich and others (1997) and Billingsley and others (2000) but that remain of unknown origin because 

they have not been drilled or further explored as of mid-2016; and (e) 4 near-surface, stratabound 

copper deposits, which are perhaps related to breccia pipes but, as of mid-2016, their origin is 

undetermined. 

The unusual solution-collapse breccia pipes of northern Arizona, some of which host high-grade 

uranium orebodies, are commonly expressed on plateau surfaces as shallow topographic depressions 

enclosed by a roughly circular, raised rim of sedimentary rocks (Wenrich and Sutphin, 1988; Wenrich, 

1992). The features sampled by the 1984–1986 survey were identified and mapped as collapse features 

that possibly overlie breccia pipes as part of a study of potential for uranium-bearing breccia pipes 

within the Hualapai Indian Reservation (Billingsley and others, 2000; Wenrich and others, 1989a, 1992, 

1997). The 37 circular features included in this report were selected for the soil survey primarily based 

on their appearance; that is, they are topographic depressions surrounded by a circular rim of rock 

exposed on the surface of the Coconino Plateau (fig. 2). 

All soil samples were collected on the weathered surface of the Kaibab Formation, which is 

capped primarily by fossiliferous sandy limestone. The Kaibab Formation forms the cap rock unit for 

the vast majority of the Coconino Plateau (Billingsley, 2000; Billingsley and Wellmeyer, 2003; 

Billingsley and others, 2006a, 2006b). 

In the soil sampling surveys of 1984, 1985, and 1986, several samples were collected 50–150 

meters outside of each collapse feature to provide background samples for comparison to the samples 

collected inside the collapse features, as shown in figure 2. In general, an equal (or nearly equal) number 

of soil samples were collected inside and outside (background areas) the collapse feature. The latitude 

and longitude information listed in the spreadsheet “Geochemical Analyses of Soils Collected on the 

Surface of the Coconino Plateau, Grand Canyon Region, Northern Arizona” (appendix 1) refers to the 

location at the center of the collapse feature. Refer to Van Gosen and Wenrich (1991) for detailed maps 

of sample locations at each feature. Only the geochemical analyses of the background soils are the 

data provided in this report. Analytical results of soil samples that were collected inside the collapse 

features are available in Van Gosen and Wenrich (1991). 
3

Figure 1. Background soil samples were collected from the surface of Coconino Plateau near the collapse 

features shown on the map, which are located in the Grand Canyon region of northern Arizona. 

The principal goal of the 1984–1986 soil sampling program was to determine if soils could 

provide a relatively inexpensive method of distinguishing collapse structures that lack mineralization 

from those that overlie breccia pipes with mineralization at depth (Wenrich and Aumente-Modreski, 

1994). However, the geochemical results of the 1984–1986 sampling survey and a recent soil study at 

the Canyon breccia pipe (Naftz and Walton-Day, 2016) indicate that soils cannot be used to distinguish 

breccia pipes with mineralization at depth from other collapse features. That is, soils at the surface of 

the collapse feature do not display a distinct geochemical contrast from nearby background soils. The 

results of the soil surveys across three uranium-bearing breccia pipes (fig. 1) found no evidence of 
4

mineralization on the surface of the collapse feature, including the soils above the Canyon pipe (Naftz 

and Walton-Day, 2016), the Mohawk Canyon pipe (Wenrich and others, 1988; Van Gosen and Wenrich, 

1991); and the SBF pipe (Van Gosen and Wenrich, 1991). Also, no additional mineralized breccia pipes 

were discovered by this soil survey. 

Figure 2. Aerial view of the “SBF” breccia pipe (fig. 1) showing the locations of background soil samples 

collected at this feature in 1985. This is an example of the radial sampling pattern employed for the background soil 

sites, with most background samples collected 50 and 150 meters beyond the outer rim of the collapse feature. The 

background soils at this site are samples 0562-AG-SC5 to 0562-BJ-SC5, rows 183 to 198, in the accompanying 

spreadsheet “Geochemical Analyses of Soils Collected on the Surface of the Coconino Plateau, Grand Canyon 

Region, Northern Arizona” (appendix 1). The center of the SBF breccia pipe is located at latitude 35.79659 North

and longitude 112.88774 West (datum of WGS84). 
5

Sample Collection

The soil samples of the Van Gosen and Wenrich (1991) study were consistently collected at 3–4 

inches (in.) of depth and just below from holes dug by a hand trowel. Sampling was done at these depths 

rather than at the surface to avoid organic matter and other extraneous surface materials, such as 

windblown material. An individual sampled weighed about 4 pounds. 

A pilot sampling study during 1984 compared the analytical results from 3–4 in. depth samples 

with 7–8 in. depth samples; the pilot study found no discernible difference in metal concentrations 

between horizons. Thus, the 3–4 in. depth was used in the subsequent larger soil sampling programs of 

1985 and 1986. A statistical summary of the analytical results is shown in table 1. 

Sample Preparation

All of the soil samples were sieved through an 80 mesh screen opening (equal to 0.0067 in.). 

The <80 mesh material was then pulverized to <100 mesh, and this <100 mesh material was submitted 

for geochemical analyses. 

Analytical Techniques

The geochemical analyses of the <80 mesh fraction of the soil samples were performed by the 

USGS Analytical Laboratory, Denver, Colorado, and Geochemical Services, Inc., Sparks, Nevada. The 

analytical methods applied to these samples by the USGS laboratory included inductively coupled 

plasma-atomic emission spectroscopy, atomic absorption, and delayed neutron activation; refer to 

Taggart (2002) for analytical processing procedures. Geochemical Services, Inc., analyzed the soil 

samples by digesting 5.0 grams of each sample (procedures are proprietary) and analyzing the dissolved 

sample by inductively coupled plasma-atomic emission spectroscopy.

Summary of Results

This report summarizes the basic statistical results of the geochemical analyses of the soil 

samples collected on the surface of the Coconino Plateau. The background soils did not exhibit elevated 

concentrations for the metals that are most commonly of environmental concern, including arsenic, 

cobalt, chromium, copper, mercury, manganese, molybdenum, lead, uranium, vanadium, and zinc. For 

example, the median concentrations of these elements are comparable to the mean values found in soils 

of the western United States as previously reported in another study. 

Soil surveys conducted over the collapse features of the Coconino Plateau have not proven 

successful in identifying breccia pipes that contain uranium deposits. That is, based on the chemistry of 

soils collected on the surface of collapse features, breccia pipes with known uranium deposits at depth 

could not be identified or distinguished from the other types of unmineralized collapse features that are 

typical of the region. 
6

Table 1. Summary statistics of geochemical analyses of soils collected on the surface of the Coconino Plateau, 

Grand Canyon region, northern Arizona.

[ppm, parts per million; DN, delayed neutron activation analyses; wt. %, weight percent; ICP, inductively coupled plasmaatomic emission spectroscopy analyses; AA, atomic absorption analyses; nr, not reported. The “Number” column provides 

the number of samples analyzed for that element. Values in the “West U.S.” column are mean concentrations in samples of 

soils in the western United States, as reported by Shacklette and Boerngen (1984)]

Element Symbol Unit Method Median Maximum Number West U.S. 

Thorium Th ppm DN 10.1 17.8 366 9.1

Uranium U ppm DN 3.5 8.8 366 2.5

Aluminum Al wt. % ICP 4.9 8.0 366 5.8

Calcium Ca wt. % ICP 2.0 14 366 1.8

Iron Fe wt. % ICP 2.3 4.1 366 2.1

Potassium K wt. % ICP 1.6 2.7 366 1.8

Magnesium Mg wt. % ICP 0.97 4.8 366 0.74

Sodium Na wt. % ICP 0.47 0.91 366 0.97

Phosphorus P wt. % ICP 0.1 0.9 366 0.03

Titanium Ti wt. % ICP 0.26 0.46 366 0.22

Silver Ag ppm AA, ICP 0.08 <2 717 nr

Arsenic As ppm AA, ICP <10 70 717 5.5

Gold Au ppm ICP <8 <8 717 nr

Barium Ba ppm ICP 430 700 366 580

Beryllium Be ppm ICP 1 2 366 0.68

Bismuth Bi ppm ICP <0.5 <10 717 nr

Cadmium Cd ppm ICP <0.5 18 717 nr

Cerium Ce ppm ICP 57 83 366 65

Cobalt Co ppm ICP 10 20 366 7.1

Chromium Cr ppm ICP 64 220 366 41

Copper Cu ppm ICP 22 390 717 21

Europium Eu ppm ICP <2 <2 366 nr

Gallium Ga ppm ICP 4.5 20 717 16

Mercury Hg ppm ICP <0.5 0.83 410 0.05

Holmium Ho ppm ICP <4 <4 366 nr

Lanthanum La ppm ICP 34 51 366 30

Lithium Li ppm ICP 28 60 366 22

Manganese Mn ppm ICP 510 1100 366 380

Molybdenum Mo ppm ICP <2 11 717 0.85

Niobium Nb ppm ICP 8 15 31 8.7

Neodymium Nd ppm ICP 30 42 366 36

Nickel Ni ppm ICP 25 62 366 15

Palladium Pd ppm ICP <0.25 <0.25 410 nr

Lead Pb ppm ICP 13 170 717 17

Platinum Pt ppm ICP <0.5 <0.5 410 nr

Antimony Sb ppm ICP <0.25 4.1 410 0.47

Scandium Sc ppm ICP 7 14 366 8.2

Selenium Se ppm ICP <1 5.8 410 0.23

Tin Sn ppm ICP <0.5 2.5 717 0.90

Strontium Sr ppm ICP 140 560 366 100

Tantalum Ta ppm ICP <40 <40 366 nr

Tellurium Te ppm ICP <0.5 1 410 nr

Thallium Tl ppm ICP <0.5 1.95 410 nr

Vanadium V ppm ICP 52 100 366 70

Yttrium Y ppm ICP 22 49 366 22

Ytterbium Yb ppm ICP 2 3 366 2.6

Zinc Zn ppm ICP 57 330 717 55
7

References Cited

Alpine, Andrea E., ed., 2010, Hydrological, geological, and biological site characterization of breccia 

pipe uranium deposits in northern Arizona: U.S. Geological Survey Scientific Investigations Report 

2010–5025, 353 p., 1 pl., scale 1:375,000, accessed August 30, 2016 at

http://pubs.usgs.gov/sir/2010/5025/. 

Billingsley, G.H., 2000, Geologic map of the Grand Canyon 30' x 60' quadrangle, Coconino and 

Mohave Counties, northwestern Arizona: U.S. Geological Survey Geologic Investigations Series I–

2688, Version 1.0, scale 1:100,000, accessed August 30, 2016, at http://pubs.usgs.gov/imap/i-2688/. 

Billingsley, G.H., Block, D.L., and Dyer, H.C., 2006a, Geologic map of the Peach Springs 30' x 60' 

quadrangle, Mohave and Coconino Counties, northwestern Arizona: U.S. Geological Survey 

Scientific Investigations Map 2900, Version 1.0 scale 1:100,000, accessed August 30, 2016, at 

http://pubs.usgs.gov/sim/2006/2900/. 

Billingsley, G.H., Felger, T.J., and Priest, S.S., 2006b, Geologic map of the Valle 30' x 60' quadrangle, 

Coconino County, northern Arizona: U.S. Geological Survey Scientific Investigations Map 2895, 

Version 1.0, scale 1:100,000, accessed August 30, 2016, at http://pubs.usgs.gov/sim/2006/2895/. 

Billingsley, G.H., and Wellmeyer, J.L., 2003, Geologic map of the Mount Trumbull 30' X 60' 

quadrangle, Mohave and Coconino Counties, northwestern Arizona: U.S. Geological Survey Geologic 

Investigations Series I-2766, Version 1.0, scale 1:100,000, accessed August 30, 2016, at 

http://pubs.usgs.gov/imap/i2766/. 

Billingsley, G.H., Wenrich, K.J., and Huntoon, P.W., 2000, Breccia-pipe and geologic map of the 

southeastern part of the Hualapai Indian Reservation and vicinity, Arizona: U.S. Geological Survey 

Geologic Investigations Series Map I-2643, 2 sheets, scale 1:48,000, includes 18-page pamphlet, 

accessed August 30, 2016, at https://pubs.er.usgs.gov/publication/i2643. 

Bills, D.J., Brown, K.M., Alpine, A.E., Otton, J.K., Van Gosen, B.S., Hinck, J.E., and Tillman, F.D., 

2011, Breccia-pipe uranium mining in northern Arizona—Estimate of resources and assessment of 

historical effects: U.S. Geological Survey Fact Sheet 2010–3050, 4 p., accessed August 30, 2016, at

http://pubs.usgs.gov/fs/2010/3050/. 

Bureau of Land Management, 2011, Northern Arizona mineral withdrawal—Final environmental 

impact statement: Bureau of Land Management, BLM/AZ/PL-11/002, accessed August 30, 2016, at

http://www.blm.gov/az/st/en/info/nepa/environmental_library/eis/naz-withdraw.html

Chenoweth, W.L., 1986, The Orphan Lode Mine, Grand Canyon, Arizona—A case history of a 

mineralized, collapse-breccia pipe: U.S. Geological Survey Open-File Report 86–510, 91 p., with 35 

p. appendix. 

Chenoweth, W.L., 1988, The production history and geology of the Hacks, Ridenour, Riverview and 

Chapel breccia pipes, northwestern Arizona: U.S. Geological Survey Open-File Report 88–648, 60 p. 

Matschullat, J., Ottenstein, R., and Reimann, C., 2000, Geochemical background—Can we calculate it?: 

Environmental Geology, v. 39, no. 9, p. 990–1000. 

Naftz, D., and Walton-Day, K., 2016, Establishing a pre-mining geochemical baseline at a uranium 

mine near Grand Canyon National Park, USA: Geoderma Regional, v. 7, no. 1, p. 76–92, accessed

August 30, 2016, at https://pubs.er.usgs.gov/publication/70168806. 

Ross, D.A., and Moreton, Christopher, 2012, Technical report on the EZ1 and EZ2 breccia pipes, 

Arizona Strip district, U.S.A.: Toronto, Canada, Roscoe Postle Associates Inc., prepared for Energy 

Fuels Inc., NI 43-101, 92 p., accessed August 30, 2016, at http://www.energyfuels.com/wpcontent/uploads/2016/04/EZ1-EZ2_Technical_Report_June_27_2012.pdf . 

Shacklette, H.T., and Boerngen, J.G., 1984, Element concentrations in soils and other surficial materials 

of the conterminous United States: U.S. Geological Survey Professional Paper 1270, 105 p., accessed 

August 30, 2016, at http://pubs.usgs.gov/pp/1270/pdf/PP1270_508.pdf. 
8

Taggart, J.E., Jr., ed., 2002, Analytical methods for chemical analysis of geologic and other materials, 

U.S. Geological Survey: U.S. Geological Survey Open-File Report 02-223, 20 p., accessed August 30, 

2016, at http://pubs.usgs.gov/of/ofr-02-0223/

Van Gosen, B.S., and Wenrich, K.J., 1991, Geochemistry of soil samples from 50 solution-collapse 

features on the Coconino Plateau, northern Arizona: U.S. Geological Survey Open-File Report 

91-0594, 281 p., accessed August 30, 2016, at http://pubs.usgs.gov/of/1991/0594a/report.pdf. 

Wenrich, K.J., 1985, Mineralization of breccia pipes in northern Arizona: Economic Geology, v. 80, 

p. 1722–1735. 

Wenrich, K.J., 1986, Geochemical exploration for mineralized breccia pipes in northern Arizona, 

U.S.A.: Applied Geochemistry, v. 1, no. 4, p. 469–485. 

Wenrich, K.J., 1992, Breccia pipes in the Red Butte area of Kaibab National Forest, Arizona: U.S. 

Geological Survey Open-File Report 92–219, 13 p.

Wenrich, K.J., and Aumente-Modreski, R.M., 1994, Geochemical soil sampling for deeply buried 

mineralized breccia pipes, northwestern Arizona: Applied Geochemistry, v. 9, p. 431–454. 

Wenrich, K.J., Billingsley, G.H., and Huntoon, P.W., 1997, Breccia-pipe and geologic map of the 

northeastern part of the Hualapai Indian Reservation and vicinity, Arizona: U.S. Geological Survey 

Miscellaneous Investigations Series Map I–2440, 2 sheets, scale 1:48,000, includes 19-page pamphlet, 

accessed August 30, 2016, at https://pubs.er.usgs.gov/publication/i2440. 

Wenrich, K.J., Billingsley, G.H., and Van Gosen, B.S., 1989a, The potential of breccia pipes in the 

National Tank area, Hualapai Indian Reservation, Arizona: U.S. Geological Survey Bulletin 1683–B, 

34 p. 

Wenrich, K.J., Billingsley, G.H., and Van Gosen, B.S., 1992, The potential of breccia pipes in the 

Mohawk Canyon area, Hualapai Indian Reservation, Arizona: U.S. Geological Survey Bulletin 

1683–D, 39 p. 

Wenrich, K.J., Chenoweth, W.L., Finch, W.I., and Scarborough, R.B., 1989b, Uranium in Arizona, in

Jenney, J.P., and Reynolds, S.J., eds., Geologic evolution of Arizona: Arizona Geological Society 

Digest 17, p. 759–794. 

Wenrich, K.J., and Sutphin, H.B., 1988, Recognition of breccia pipes in northern Arizona, in

VandenDolder, E.M., ed., Fieldnotes: Tucson, Ariz., Arizona Bureau of Geology and Mineral 

Technology, v. 18, no. 1, p. 1–5 and 11. 

Wenrich, K.J., Van Gosen, B.S., Balcer, R.A., Scott, J.H., Mascarenas, J.F., Bedinger, G.M., and 

Burmaster, Betsi, 1988, A mineralized breccia pipe in Mohawk Canyon—Lithologic and geophysical 

logs: U.S. Geological Survey Bulletin 1683–A, 66 p. 
9

Appendix 1. Geochemical Analyses of Soils Collected on the Surface of the 

Coconino Plateau, Grand Canyon Region, Northern Arizona

The Excel spreadsheet Appendix-1.xls provides geochemical analyses of soils collected on the 

surface of the Coconino Plateau, Grand Canyon region, northern Arizona. 

ISSN 2331-1258 (online)

http://dx.doi.org/10.3133/ofr20161160