TANK MOUNTAINS

WESTERN ARIZONA

This is source is the farthest western source in Arizona. The source is located on the Yuma Proving Grounds in the central Tank Mountains UTM Zone 11 809360m Easting by 3673520m Northing, Department of Defense Palomas Mountain Quad 1:50,000 scale, north central Yuma County. The first samples were recovered by John R. Cook during a helicopter archaeological reconnaissance of the proving grounds in 1988. The nodules were within the Quaternary alluvium and embedded within a silicic ash flow. The five nodules analyzed are all less than three centimeters in diameter, but appear to be excellent media for tool production (since this time an additional ten samples have been analyzed some 5 cm in diameter; see Shackley 1991).

The source area was recorded by Rogers as A-111 (SDMOM) as a San Dieguito (Paleoindian) through Amargosa (Archaic) period site (1966:177). Rogers notes that the environment would be sufficient for late period occupation, but he recorded no late material, nor the obsidian nodules. Cook recovered a late period triangular concave based point produced from the Tank Mountain material at White Tanks. A photograph of the tanks in Rogers (1966:70) shows the ash flow tuff environment. The tanks have been eroded into the tuff sediments. Presumably the material has eroded into the local washes, but recent archaeological survey in the area has failed to locate any geological obsidian in surrounding alluvium (Jerome Schaefer: personal communication 1989). The source was published in Kiva (Shackley 1991).

Raw elemental concentrations for Tank Mountain source standards. All measurements in parts per million (ppm).

SAMPLE

Ti

Mn

Fe

Rb

Sr

Y

Zr

Nb

Ba

WT1 607.604 389.147 10255.978 160.387 147.003 27.74 122.227 23.691 945.9
WT2 564.247 387.385 10255.555 158.667 145.466 26.938 125.538 19.367 938.424
WT3 559.681 438.559 10642.889 166.752 146.885 22.629 123.873 15.083 865.58
WT4 1249.691 435.068 10993.534 171.99 157.43 21.452 118.491 21.723 711.549
WT5 734.715 418.082 10302.078 159.726 141.694 21.818 120.813 17.22 870.06
WT6 646.617 474.744 11117.079 166.721 148.786 26.069 126.134 21.888 812.678
WT7 582.081 472.779 11372.252 177.872 156.969 26.195 129.047 21.968 1028.056
WT8 784.837 512.193 11915.143 180.572 160.139 25.055 128.913 19.001 936.897
WT9 639.119 442.217 10687.309 158.932 148.037 24.483 122.922 20.445 946.11
WT10 563.253 410.423 10489.811 162.554 148.616 25.004 118.546 20.211 930.482
WT12 549.042 402.987 10587.647 161.439 145.023 24.433 123.758 18.091 934.255
LOC 3 660.877 407.293 10835.227 164.894 146.795 23.487 124.152 18.411 930.328
LOC 2-1 668.097 448.422 11046.384 170.026 150.563 23.874 127.035 20.393 801.995
LOC 2-2 617.894 427.981 10519.548 168.395 148.639 25.192 130.192 20.995 905.384
WT11 527.029 381.869 10327.606 152.275 141.913 23.812 119.753 26.399 760.38

This page maintained by Steve Shackley (shackley@berkeley.edu).
Copyright 2002 M. Steven Shackley. All rights reserved.
Revised: 19 August 2015

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