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  870 287 11084 105 83 22 139 5 996 30 58
D1-10  862 306 11469 107 84 26 142 8 1067 33 61
D1-2  968 323 12624 114 86 25 145 5 927 32 57
D1-3  711 278 10320 98 78 24 128 8 1087 31 65
D1-4  874 291 10981 103 83 26 140 8 936 30 49
D1-5  701 273 10353 98 76 20 128 6 1033 28 63
D1-6  905 311 11772 110 91 28 141 8 957 25 58
D1-7  883 319 11531 106 85 26 142 7 1092 32 71
D1-8  625 231 9149 94 73 20 128 3 920 26 56
D1-9  933 298 11814 113 91 22 146 3 931 27 55
D2-1  885 286 11451 110 88 23 142 7 917 22 60
D2-10 903 297 10311 100 83 25 134 4 795 25 48
D2-11 1066 287 11308 107 85 25 142 2 812 30 48
D2-13 1119 328 11758 112 89 26 151 5 786 29 52
D2-14 961 318 11976 113 85 22 141 4 931 26 64
D2-2  947 312 11673 108 91 23 143 4 943 32 58
D2-3  996 357 13002 112 91 25 149 6 937 28 58
D2-4  857 279 11256 105 83 21 142 7 911 31 53
D2-5  985 304 11845 112 88 25 144 10 989 31 64
D2-6  783 320 10997 102 79 25 136 5 990 37 58
D2-7  922 334 12432 116 90 22 146 9 967 30 63
D2-8  808 288 11062 102 82 25 134 6 880 25 57
D2-9  807 312 10791 97 79 25 135 8 1014 29 62
TV1  840 250 11180 95 83 23 144 9      
TV2  855 220 11140 97 85 22 143 6      
TV3  828 216 10980 95 81 20 143 5      
TV4  889 176 10390 92 72 20 125 6      
TV5  810 177 10277 85 72 21 135 3      
TV6  788 167 9972 86 75 20 129 7      
TV7  730 168 10581 91 83 21 132 11      
TVMD1 830 249 10270 100 82 25 132 5 832 22 54
TVMD2 986 294 11317 108 89 25 143 9 828 19 56
TVR1  922 293 11384 105 84 26 139 9 864 24 45
TVR2  823 247 10552 96 79 22 133 7 998 28 64
TVR3  905 244 10558 102 82 23 131 9 856 22 56
TVR4  917 232 9297 88 75 24 126 6 838 20 53
TVR5  788 217 9400 93 73 21 125 10 1057 27 67
TVR6  1068 377 12833 118 90 30 143 6 798 21 54
 

Mean and central tendency for the data in above table.  All measurements in ppm

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)

and the recent references below:

Laylander, D. 2006, Obsidian studies and Baja California's Prehistory.  Memorias Balances y Perspectivas 2005: IV Encuentro Binacional-La Antropología e Historia de Baja California (CD ROM).  Centro INAH Baja California, Mexicali.

Panich, L.M., A. Porcayo M., M.S. Shackley, 2012, Obsidian sources of Northern Baja California.  California Archaeology 4:183-200.

Panich, L.M., É. Morachel M., and A. Porcayo M., 2015, Exploring patterns of obsidian conveyance in Baja California, Mexico.  Journal of California and Great Basin Anthropology 35:257-274.

Panich, L. M., M.S. Shackley, and A. Porcayo M., 2017, A reassessment of archaeological obsidian from southern Alta California, and northern Baja California.  California Archaeology 9:53-77.

Shackley, M.S., J.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 61:718-731.

Sosa, A.D., 2014, Obsidian exchange in prehistoric Baja California: an initial look at regional exchange networks in the peninsula.  Master's thesis, Department of Anthropology, California State University, Northridge.

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