RED HILL

WESTERN NEW MEXICO

Collections from Sections 4 through 11,14,15,17 R19W, T2S USGS Red Hill 7.5' Quad, northwest Catron County, New Mexico.

Red Hill is, perhaps, one of the most petrologically unique obsidians in the Southwest. The nodules are found within a conglomerate that consists mainly of basalt cobbles, some quartzite and very little rhyolite (see also Findlow and Bolognese 1982:56). Findlow and Bolognese state that the obsidian extends "over much of Catron County" (1982:56). While the context is a Quaternary basalt, the obsidian is apparently related to earlier Tertiary silicic eruptions of the Mogollon-Datil Formation in the area (Elston et al. 1976; Willard and Weber 1958). Nodule densities are very low, usually less than 5 per 25 m2. The largest nodule recovered was 8 cm in diameter, but most of nodules were 5 cm or less. Nodules up to 25 cm are reported by Findlow and Bolognese (1982:56; in 1995 after recent grading we recovered a number of nodules over 8 cm in diameter). Cortical material varies from a thin gray or brown to glassy. The aphyric glass ranges from a nearly transparent brown (like Superior) to a cloudy or banded light gray. The knapping quality is excellent, equal to any in the Southwest. In August 2012 collected one nodule over 10 cm in the same locality.

Bipolar reduction stations and isolated flakes commonly occur, but in very low densities commensurate with the low geologic density. A few biface preform fragments were recorded, all less than 5 cm in length. References are those noted above.

Raw elemental concentrations for Red Hill source standards. All measurements in parts per million (ppm). RH samples collected in 1986 and 1995.  082912 prefixes collected in August 2012.

SAMPLE Ti Mn Fe Rb Sr Y Zr Nb Ba1
RH1  399 682 7335 183 14 41 72 48  
RH2  353 804 7682 222 6 49 74 58  
RH3  302 590 6522 164 12 34 67 48  
RH4  417 820 8240 186 14 37 71 52  
RH5  275 524 6020 174 5 41 67 59  
RH6  397 595 6803 166 12 36 65 50  
RH7  379 597 7010 176 12 40 68 48  
RH8  365 445 5986 138 12 32 61 40  
RH9  390 596 6709 171 12 37 68 51  
RH10  391 614 7050 167 11 37 71 48  
RH11  373 582 7023 163 12 35 68 47  
RH12  340 609 6780 171 15 35 67 46  
RHD  294 792 7443 216 9 46 74 66  
RHE  377 587 6989 170 11 36 67 46  
082912-1-1 795 544 7985 164 17 33 65 50  
082912-1-2 914 669 9371 206 11 47 69 63 0
082912-13 824 502 7840 159 15 36 60 51 21
082912-1-4 886 716 9239 193 18 39 69 53 0
082912-1-5 791 571 8065 168 15 36 64 47 21
082912-1-6 805 491 7624 153 14 38 59 48 0
082912-1-7 808 504 7861 159 17 36 61 49 4
082912-1-8 952 578 8709 170 17 34 62 48 35
082912-1-9 1099 627 10040 176 20 39 65 50 9
082912-1-10 791 655 9265 203 12 47 74 58 12
082912-1-12 854 716 9032 204 9 52 68 61 42
082912-1-13 878 666 9149 208 12 47 68 61 9
082912-1-14 980 546 8889 166 19 36 64 49 8
082912-1-15 837 543 8141 164 15 40 62 49 0
082912-1-16 799 492 7686 152 14 35 65 50 33
082912-1-17 775 596 8309 197 12 48 66 65 9
082912-1-18 855 606 8756 177 17 41 65 51 34
082912-1-19 944 494 8618 155 17 33 68 52 4

                                                                        1 Many of the samples Ba concentrations are below the detection limits.

RED HILL, NM, MEAN AND CENTRAL TENDENCY 

 

N

Minimum

Maximum

Mean

Std. Deviation

Ti

32

275

1099

645

263.7

Mn

32

445

820

605

92.8

Fe

32

5986

10040

7880

1036.0

Rb

32

138

222

176

20.2

Sr

32

5

20

13

3.5

Y

32

32

52

39

5.3

Zr

32

59

74

67

3.9

Nb

32

40

66

52

6.1

Ba

17

0

42

14

14.1

 

 MAJOR OXIDE DATA FOR VULTURE AND ANALYSIS OF RGM-1 USGS SOURCE STANDARD

Sample

SiO2

Al2O3

CaO

Fe2O3

K2O

MgO

MnO

Na2O

TiO2

082912-1-5

78.159

12.051

0.698

0.786

4.507

<.001

0.117

3.498

0.062

RGM1-S4

75.680

12.477

1.3024

1.806

4.550

<.001

0.0379

3.77

0.196

This page maintained by Steve Shackley (shackley@berkeley.edu).
Copyright 2013 M. Steven Shackley. All rights reserved.
Revised: 19 August 2015

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