VALLE DEL AZUFRE

BAJA CALIFORNIA SUR

ABSTRACT

From:

Shackley, M. Steven, Justin R. Hyland, and María de la Luz Gutiérrez M. (1996). Mass production and procurement at Valle del Azufre: a unique archaeological obsidian source in Baja California Sur. American Antiquity 61(4):718-731.

Valle del Azufre is a newly discovered source of high quality obsidian in central Baja California which exhibits the most intensive exploitation of any known source in the greater US Southwest/Northwest Mexico. Over 15 subsurface trenches and at least one adit occur at the source. Evidence for the prehistoric distribution of Valle del Azufre obsidian is presented based on EDXRF characterization of the source material and artifacts from the Baja California peninsula. Despite the intensity of exploitation at the source, the distribution of Valle del Azufre glass appears to be largely restricted to the central part of the peninsula.

Valle del Azufre es un recién descubierto yacimiento de obsidiana de alta calidad. Este yacimiento exhibe una explotación intensiva, mayor de cualquier otro yacimiento en el suroeste de los Estados Unidos/noroeste de México. Hay más de 15 minas en el yacimiento. Se presenta evidencia acerca de la distribución prehistórica de obsidiana de Valle del Azufre basado en la caracterización química de la materia prima y artefactos que proceden de diversas partes de la península de Baja California. A pesar de la intensidad de la explotación en el yacimiento, aparentemente la distribución del vidrio volcánico de Valle del Azufre se restringe principalmente en el área central de la península.
 


Location of Valle del Azufre and important archaeological and geological features of the region. Click on the Laguna San Ignacio region or this thumbnail

to view a NASA satellite image of the region.

 

Vdazuf2.jpg (56764 bytes)

Prehistorically excavated tailings at Valle del Azufre, Baja California Sur (Sea of Cortez in background).

 

Total station map of the two domes and relevant geological and archaeological features. Datum in SE (lower right) corner.

 

Vdazuf1.jpg (81584 bytes)

One of the trenches found at Valle del Azufre, Baja California Sur. Over 95% of the obsidian in the foreground is culturally altered. 

 

Vdaztunl.jpg (47802 bytes)

Bidirectionally excavated tunnel at Valle del Azufre, Baja California Sur. Note large lenticular nodules embedded in the tuff, undoubtedly the goal of prehistoric procurement. 


Table 1. Elemental concentrations for Valle del Azufre source standards. All measurements in parts per million (ppm). Sample #s correspond to collection localities (D1=Dome 1; D2=Dome 2; TV=Tres Virgenes).

 

SAMPLE

Ti

Mn

Fe

Rb

Sr

Y

Zr

Nb

Ba

La

Ce

D1-1 869.81 286.71 11083.98 105.44 82.68 21.77 138.98 4.72 995.67 30.15 58.13
D1-10 862.23 305.80 11469.47 107.34 83.82 25.82 141.88 8.09 1066.60 32.98 61.40
D1-2 967.73 322.97 12623.83 113.57 86.48 25.36 144.93 5.48 927.16 32.05 56.50
D1-3 710.61 278.32 10319.50 97.74 77.86 24.48 128.36 7.66 1087.15 31.23 64.60
D1-4 874.39 291.04 10981.00 102.70 83.44 25.61 140.01 7.63 936.34 30.40 49.18
D1-5 700.71 272.94 10352.88 98.01 75.72 19.74 127.92 6.13 1032.63 27.85 62.54
D1-6 905.47 311.06 11771.69 109.54 90.72 27.71 140.61 7.50 957.02 25.31 57.54
D1-7 882.80 318.92 11531.17 106.26 85.01 26.05 141.96 6.86 1091.53 32.36 70.50
D1-8 624.63 231.09 9149.05 94.16 73.37 20.12 127.66 3.06 919.75 25.98 55.87
D1-9 933.17 297.67 11813.64 113.00 91.32 21.73 145.71 3.02 930.68 26.80 54.70
D2-1 884.50 285.56 11450.81 109.88 88.11 23.00 142.00 6.86 917.32 21.78 59.92
D2-10 902.83 297.10 10310.66 100.25 82.69 24.64 133.93 3.92 794.72 24.59 47.54
D2-11 1066.11 286.69 11308.41 107.19 85.49 24.94 141.62 1.87 812.02 29.80 47.54
D2-13 1118.99 328.11 11757.72 111.61 89.38 26.27 151.07 4.89 785.84 29.03 51.74
D2-14 960.61 317.60 11976.16 113.20 85.37 22.08 141.29 4.13 931.13 26.25 63.99
D2-2 947.01 312.48 11672.78 107.70 90.87 22.96 143.17 4.26 943.03 31.85 57.51
D2-3 996.23 357.31 13001.86 111.79 91.22 24.94 149.32 6.04 936.95 28.36 57.63
D2-4 856.92 278.53 11256.19 104.57 83.20 21.38 141.55 6.97 910.71 31.38 53.20
D2-5 984.50 304.24 11845.12 111.94 88.03 24.53 143.78 9.83 989.42 31.43 63.57
D2-6 783.25 319.69 10997.05 101.91 78.84 25.38 135.82 4.66 990.08 36.70 58.13
D2-7 922.33 334.22 12432.37 116.22 89.90 21.95 146.40 8.72 967.27 29.61 63.28
D2-8 808.27 287.93 11061.92 102.38 81.86 24.52 133.77 6.26 879.95 25.05 56.56
D2-9 806.73 311.79 10790.50 97.16 79.22 25.12 134.91 8.24 1014.13 29.25 61.81
TV1 840.11 250.24 11180.00 95.42 82.98 23.00 144.19 9.38      
TV2 854.89 220.03 11140.00 96.75 85.17 21.87 142.82 5.73      
TV3 828.39 216.31 10980.00 94.81 80.56 20.29 142.60 4.91      
TV4 889.05 175.61 10390.00 91.91 71.53 20.22 124.59 6.44      
TV5 809.73 176.68 10277.00 85.37 72.07 20.85 135.03 2.85      
TV6 788.30 166.53 9972.00 86.26 75.02 19.98 128.78 6.57      
TV7 729.62 168.06 10581.00 90.76 83.05 21.28 131.96 10.62      
TVMD1 830.20 248.76 10269.51 100.37 81.50 24.51 132.13 5.12 832.45 22.00 54.42
TVMD2 985.57 294.05 11316.68 107.59 89.37 25.18 142.70 8.63 827.82 19.16 56.26
TVR1 921.68 292.90 11383.53 105.34 83.84 26.08 138.65 8.90 863.79 23.61 45.12
TVR2 823.23 247.28 10551.66 96.09 78.64 22.41 133.47 7.19 997.62 28.04 64.25
TVR3 905.02 244.25 10558.27 102.13 82.14 22.95 131.37 9.21 856.01 22.48 55.67
TVR4 917.11 231.76 9296.93 88.09 75.25 23.64 126.05 6.20 837.82 20.12 53.05
TVR5 788.09 216.82 9399.71 93.23 72.74 20.84 125.26 10.16 1056.99 27.46 66.74
TVR6 1067.90 377.38 12833.42 117.69 89.52 29.81 143.24 6.12 797.50 21.12 54.15

For more information about the geology and chemistry of the sources of archaeological obsidian in the Baja California region, contact:

M. Steven Shackley (shackley@berkeley.edu)

This page maintained by Steve Shackley
Copyright © 2015 M. Steven Shackley. All rights reserved.
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