LAGO BARREAL

Secondary Deposits

EAST-CENTRAL CHIHUAHUA

These samples were collected by Philip LeTourneau (University of New Mexico) and submitted to this lab for analysis. The samples were recovered from alluvium around the lake and appear to be mildly peralkaline (high Fe and Zr). These samples have occurred in surface collections of Archaic period cruciforms in northern Chihuahua, and a few sites in the Big Bend region of Texas. The nodules are typical of Tertiary marekenites in the Basin and Range Province. None display the green cast often associated with peralkaline glasses. Most are smoky gray to brown.

Elemental concentrations for Lago Barreal, Chihuahua source standards collected by LeTourneau. All measurements in parts per million (ppm).

Sample Ti Mn Fe Zn Rb Sr Y Zr Nb Ba Ce Pb Th
1 1573 761 19233 209 265 12 79 668 45 36 66 33 32
2 1518 702 18129 166 254 9 71 646 43 1 111 31 38
3 1536 681 17696 201 238 11 73 597 39 0 57 31 30
4 1616 759 19087 201 257 11 74 642 42 12 74 34 25
6 1481 717 17841 205 243 13 75 611 39 32 86 33 34
7 1579 736 18524 231 239 12 69 597 39 0 108 33 38
8 1532 729 18551 201 244 11 70 627 34 39 100 35 24

Mean and central tendency for the data above

  N Minimum Maximum Mean Std. Deviation
Ti 7 1481 1616 1548 44.9
Mn 7 681 761 726 29.2
Fe 7 17696 19233 18437 588.2
Zn 7 166 231 202 19.3
Rb 7 238 265 249 10.2
Sr 7 9 13 11 1.0
Y 7 69 79 73 3.6
Zr 7 597 668 627 27.0
Nb 7 34 45 40 3.6
Ba 7 0 39 17 17.7
Ce 7 57 111 86 21.2
Pb 7 31 35 33 1.5
Th 7 24 38 31 5.8

 

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Copyright © 2021 M. Steven Shackley. All rights reserved.
Revised: 06 June 2021

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