MP3260602

MP3260601

2TMP01

96TMP04

96TMP03

96TMP18

96TMP27

3MRG–1

96TMP19

04TMP24

96TMP17

3MRG–8

05TMP01

6RTCD10

MP3270601

96TMP20

96TMP38

3MRG–2

96TMP24

2MRG–5

4MRG–17

97TMP50

96TMP36

96TMP35

4TMP22

2MRG–11 4TMP21

02TMP02

96TMP09

96TMP22a

96TMP22b

04TMP23

96TMP08

96TMP07

96TMP14

2MRG–2

96TMP15

20

30

30

25

25

25

20

35

30

5

12

U.S Forest Service

Twelve Hundred Well

TD 1,200 

COCHITI

FAULT

COCHITI

FAULT

CERRO

CERRO MICHO

COLORADO

FAULT

FAULT

TWIN

HILLS

FAULT

CERRO

PORTILLO

FAULT

CERRO

PORTILLO

FAULT

Tcm

Tcm

Tcmc

Tcmc

Tcmc

Tcm

Tcm

Tbc

Tbcc

Tcmc

Tcmc

Tcmc

Tcmc

Qc

Qc

Qac

Qec

Qec

Qec

Qac

Qfd

Qsw

Qsw

Qsw Qsw

Qac

Qac

Qac

Qac

Qsw

Qbxc

Tayc

Tbclc

Tbcl

Tbsc Tbs

Qc

Qc

Tbta

Tbcl

Tayc

Tayc

Tay

Tay

Qbxc

Qbx

Qg

Qbx

Qbx

Qbx

Qsw

Qsw

Qsw

Tb

Qsw

Qsw

Qsw

af

Qsw

Qsw

Qfd

Qfd

Qfd

Qfd

Qac

Qac

Qac Qac

Qac

Qsw

Qsw

Qsw

Qsw

Qsw

Qsw

Qsw

Qc

Qc

Qoc Qo

Qo

Qbu

Qbu

Qbu

Qto

Qto

Qto

Qbuc

Qba

Qba

Qbu

Qbuc

Qbu

Qbu

Qc

Qec

Qc

Qc

Qc

Qc

Qcu

Qcu

Qc

Qc

Qsw

Qsw

Qsw

Qsw

Qcb

Qcb

Qcb

Qcb

Qcb

Qsw

Qsw

Qsw

Qsw

Qsw

Qsw

QswQcl

Qtd

Qtd

Qaec

Qaec

Qcb

Qcb

Qcb

Qcb

Qbt

Tat

Qbt

Qcbc

Qaec

Qaec

Qtdc

Qsw

Tca

Tca

Tca

Tca

Tcac

Tca

Tcp

Tcp

Tcp

Tcp

Tcp

Tcp

Tcpc

Tca

Tca

Tca

Qae

Qae

Qsw

Qec

Qsw

Qac

Qac

Qac

Qac

Qac

Qac

Qcu

Qac

Qac

Qac

Qac

Qac

Qac

Qc

Qc

Qec

Tm

Tm

Tm

Tm

Tmc

Tm

Qsw

Qsw

Qsw

Qbz

Qbz

Qbz

Qsw

Qsw

Qsw

Qtd

Qtdc

Qtd

Qbzc

Qbzc

Qfd

Qto

Qto

Qto

Qto

Qtoc

Qtoc

Qfd

Qfd

Qfd

Qsw

Qsw

Ttx

Ttx

Ttx

Qc

Qsw

Qsw

Qsw

Qsw

Qsw

Qsw

Qac

Qac

Qac

Qac

Qc

Qc

Qc

Qc

Qfd

Qfd

Qfd

Qba

Qfd

Qc

Qc

Qc

Qc

Qc

Qc

Qc

Qc

Qac

Qc

Qg

Qg

Qc

Table 2. Whole rock major oxide and trace element analyses of representative Cerros del Rio volcanic field samples

[LOI, loss on ignition]

Quadrangle Tetilla 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Tetilla 

Peak

Turqoise

Hill

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Montoso 

Peak

Cochiti 

Dam

Cochiti

Dam

Cochiti 

Dam

Cochiti

Dam

Montoso 

Peak

Cochiti

Dam

Eruption series 11111111 2 1111 111111112222 22222222222 2222333 3

Map unit Tat Tcm Tcm Tbc Tbcc Tbs Tbs Tayc Tay Tcac Tca Tca Tcp Tcp Tcp Tm Tm Tbcl Tbcl Tbcl Ttx Qbu Qbu Qbx Qbx Qae Qae Qbt Qbt Qcb Qcb Qto Qto Qo Qo Qtd Qtd Qtdc Qb Qb Qcl Qcl Qcu Qcu

Sample no. 96TTP01 04TMP23 6RTCD10 3MRG–1 96TMP18 96DTP04 96TTH02A 02TMP02 2MRG–11 96TMP38 96TMP20 96TMP24 MP3260601 96TMP04 96TMP36 96TMP08 96TMP07 96TMP35 04TMP21 04TMP22 96TMP27 2MRG–2 96TMP15 4MRG–17 96TMP09 MP3270601 05TMP01 96TMP22a 96TMP22b 2MRG–5 3MRG–2 MP3260602 96TMP03 96TMP17 96TMP14 3MRG–8 96TMP19 04TMP24 96DCD01 96TCD01 6RTCD4 DN–96–28b 97TMP50 3MRG–4

major elements wt% oxides

SiO2 62.19 59.00 60.00 52.70 52.40 50.20 50.70 48.90 48.90 56.09 59.48 60.70 57.70 60.60 60.03 50.00 51.00 54.70 54.70 52.90 52.79 52.10 51.65 46.80 47.30 56.70 55.30 50.00 49.71 50.10 50.20 52.90 50.10 60.60 59.10 50.60 55.90 51.10 46.69 50.43 58.30 56.19 60.10 59.20

TiO2 0.62 0.79 0.73 1.35 1.45 1.51 1.42 1.81 1.79 0.93 0.78 0.66 1 0.87 0.86 1.59 1.47 1.57 1.64 1.42 1.44 1.47 1.46 1.75 1.88 1.1 1.18 1.54 1.53 1.55 1.52 1.24 1.44 0.85 0.98 1.43 1.11 1.56 1.52 1.45 1.06 1.22 0.95 1.03

Al2

O3 14.89 15.8 15.7 14.6 15.2 15.4 15.1 15.4 15.3 15.7 16.09 15.6 16.1 15.8 15.89 16.4 16.2 15.5 15.5 15.5 17.91 17.5 17.3 15.1 15.6 17.5 17.1 17.5 17.49 17.9 17.5 15.7 16 16.2 16.87 15.6 17.0 17.8 15.27 15.47 15.8 15.99 16.1 15.8

Fe2

O3 4.54 5.84 5.44 7.99 8.33 9.02 8.82 10.8 10.7 6.7 5.74 5.49 6.44 5.46 5.67 10.4 9.88 9.60 9.83 10.1 8.09 8.66 8.55 10.4 11.2 7.06 7.50 9.53 9.73 9.64 9.41 8.4 9.41 5.56 6 9.11 6.85 8.76 12.35 9.72 7.42 8.11 6.83 7.07

MnO 0.09 0.10 0.1 0.13 0.14 0.15 0.15 0.17 0.17 0.11 0.1 0.1 0.1 0.09 0.09 0.16 0.15 0.14 0.14 0.14 0.13 0.14 0.14 0.17 0.18 0.11 0.12 0.15 0.15 0.16 0.15 0.13 0.14 0.09 0.09 0.15 0.11 0.14 0.17 0.15 0.11 0.12 0.1 0.11

MgO 2.69 3.90 3.09 7.10 6.74 6.91 7.1 7.57 7.47 4.3 3.47 3.82 3.15 2.45 3.06 6.1 5.82 3.87 4.21 6.12 4.04 4.67 4.42 7.74 7.37 3.22 4.09 4.99 4.07 5.03 5.16 6.32 6.85 2.68 2.78 7.11 3.17 4.28 8.03 6.68 3.75 4.68 3.2 3.70

CaO 5.12 5.92 5.54 8.25 8.03 7.81 7.46 8.97 9.01 6.88 5.63 5.52 5.78 4.8 5.3 9.22 8.73 6.84 6.99 7.91 6.82 7.65 7.83 9.18 9.08 6.2 6.88 8.48 8.49 8.75 8.39 8.11 8.47 5.17 5.49 8.52 6.41 7.16 10.03 8.45 6.43 6.78 5.73 5.99

Na2

O 4 4.12 4.41 3.68 3.31 3.94 3.5 3.67 3.49 4.38 4.04 4.05 4.44 3.97 4.12 3.74 3.7 3.77 3.72 3.49 4.75 4.3 4.35 3.67 3.75 4.52 4.26 4.07 4.14 3.79 4.10 4.09 4.09 4.21 4.39 3.72 4.20 4.68 3.27 3.55 4.22 3.70 4.11 3.90

K2

O 2.91 2.46 2.63 2.06 2.12 2.18 2.14 1.95 1.93 2.22 2.32 2.44 2.65 3.31 2.73 1.4 1.54 1.82 1.67 1.35 2.14 2.06 2.04 1.25 1.85 2.13 1.90 1.85 1.81 1.78 1.82 1.82 1.75 2.57 2.33 1.66 2.29 2.05 0.76 1.58 2.18 1.94 2.18 2.07

P2

O5 0.51 0.56 0.51 0.70 0.68 0.89 0.81 0.89 0.87 1.01 0.54 0.42 0.9 0.71 0.7 0.53 0.51 0.62 0.66 0.41 0.95 0.92 0.97 1.00 0.94 0.66 0.61 0.91 0.94 0.94 0.92 0.74 0.96 0.48 0.59 0.77 0.66 0.95 0.6 0.58 0.38 0.46 0.43 0.40

LOI 1.9 0.75 1.19 1.26 0.94 1.44 1.64 0.1 0.38 0.84 1.42 0.83 1.34 1.36 0.97 0 0.17 0.81 0.39 0.26 0.2 0.39 0.75 2.39 0.06 1.1 0.06 0.41 0.48 0.58 0.14 0.35 0.15 0.99 0.92 0.48 1.30 0.06 1.32 1.83 0.42 0.34 0.42 0.25

Total 99.46 99.24 99.34 99.82 99.34 99.45 98.84 100.23 100.01 99.16 99.61 99.63 99.60 99.42 99.42 99.54 99.17 99.24 99.45 99.60 99.26 99.86 99.46 99.45 99.21 100.30 99.00 99.43 98.54 100.22 99.31 99.80 99.36 99.40 99.54 99.15 99.00 98.54 100.01 99.89 100.07 99.53 100.15 99.52

trace elements (ppm)

Cr 40.8 77.10 70 218.00 218.00 194 195 174.00 169.00 26.7 61.5 105.00 10.10 19.7 31.4 153 157 82.20 77.60 198.00 6.13 59.80 56 185.00 174 5.99 17.60 158.00 35.9 30.10 38.10 209.00 140.00 19.00 8.58 223.00 7.31 3.09 266 205 70 98 56.80 63.30

Ni 35.2 69.60 58 173.00 174.00 129 134 120.00 136.00 62.7 49.4 63.80 31.70 28.4 40.11 67.3 65.9 39.20 43.40 82.00 25.4 51.90 56.4 144.00 128 20.50 44.90 72.40 39.3 43.90 49.10 106.00 121.00 28.80 20 139.00 22.40 24.10 155 139 46 71 42.60 45.00

Ba 1420 1340 1540 1070 928 1310 1270 1130 1070 1840 1330 1260 1990 1680 1570 763 865 1000 972 758 1820 1340 1590 1170 1090 1360 1060 947 1200 1360 1550 1220 1140 1340 1670 1190 1470 1350 460 808 1180 978 1200 1220

Rb 53.4 38.10 43.9 39.80 37.20 37.8 38.8 35.70 33.70 33.2 35.5 37.3 42.8 51.6 45.2 22.2 23.9 29.70 23.90 21.50 24.8 28.70 28.8 14.10 31 27.7 26.10 29.30 31.5 29.30 35.10 30.4 28.2 35.00 33.4 21.90 27.20 31.80 14.8 26.9 32.3 30 37.6 30.10

Th 10.7 9.91 10.8 8.08 7.59 10.7 10.8 7.32 6.85 11 8.7 8.3 10.4 11.1 8.54 4.97 5.64 6.91 6.72 4.81 11.8 11.40 10.4 9.43 8.47 10.6 8.18 5.63 9.3 9.51 10.10 10 11.2 8.88 8.73 9.42 9.94 11.40 3.96 5.33 4.8 4.69 6.8 5.07

Ta 2.51 2.15 1.9 2.64 2.49 3.15 3.04 2.90 2.67 2.98 1.98 1.4 2.7 3.24 2.62 1.95 2.02 1.68 1.64 1.35 3.12 3.10 3.07 2.97 3.2 1.7 1.74 2.02 2.71 2.71 2.74 2.2 2.2 1.71 1.94 2.41 1.98 3.20 1.37 1.93 1 1.25 1.1 1.15

La 53.9 58.30 61.4 48.60 46.50 64.6 64.2 58.60 56.70 93.1 57 49 79.6 67.8 63.9 37.1 37.9 54.60 52.70 36.90 77.9 78.60 76.8 71.30 69.5 69.4 51.90 39.40 69.2 71.60 74.80 67.5 79 54.10 58.5 66.60 64.20 77.60 33.3 36.4 43.1 37.90 45.1 41.30

Ce 92 95.00 101 86.60 81.50 120 116 113.00 107.00 155 94.8 78 128 119 110 66.8 68.2 90.70 88.70 63.90 132 132.00 126 125.00 123 107 85.60 70.80 121 126.00 129.00 106 123 89.10 98.8 110.00 106.00 134.00 64.4 63.7 77.1 66.30 74.4 71.20

Sr 907 1010 998 796 764 1080 1100 1240 1180 1720 994 820 1570 1240 1160 752 704 557 580 526 1420 1420 1280 1330 1280 1140 946 704 1180 1310 1180 1280 1330 820 996 1180 1060 1390 779 663 778 792 797 685

Sm 5.78 5.89 5.9 7.17 6.37 8.65 8.28 10.10 9.76 8.81 6.2 4.8 7.4 7.52 7.36 6.59 6.19 6.35 6.25 4.98 8.92 9.45 8.9 9.24 10.6 6.8 6.04 6.23 8.67 9.33 9.42 7.4 8.4 5.89 6.89 7.77 7.06 8.95 6.31 5.51 5.6 5.76 5.3 5.89

Zr 191 182 141 186 187 214 204 230 232 226 179 162 229 198 205 159 167 201 198 150 266 264 248 237 237 217 199 176 233 266 286 159 207 218 230 224 224 251 173 161 143 148 171 184

Hf 4.44 4.33 4 4.21 3.97 4.41 4.26 5.05 4.82 4.9 4.4 4 5 4.96 4.98 3.52 3.62 4.55 4.40 3.55 5.47 5.46 5.23 5.06 4.95 5 4.22 3.79 4.59 4.76 4.94 4 4 5.08 5.21 4.64 5.26 5.38 2.99 3.29 4 3.91 4 4.48

Tb 0.604 0.64 0.71 0.75 0.74 0.889 0.832 1.00 0.95 0.81 0.644 0.65 0.95 0.696 0.701 0.771 0.727 0.81 0.80 0.73 0.916 0.93 0.903 1.04 1.3 0.94 0.73 0.81 0.97 0.95 0.99 0.94 1.01 0.67 0.704 0.91 0.82 0.97 0.785 0.701 0.71 0.65 0.75 0.66

Yb 1.78 1.74 1.8 2.09 2.06 2.36 2.08 2.54 2.39 2.09 1.87 1.7 1.9 1.87 1.94 2.14 2.13 2.20 2.19 2.09 2.39 2.57 2.33 2.64 2.45 2.3 1.98 2.24 2.42 2.54 2.51 2.2 2.2 1.89 1.94 2.36 2.12 2.59 2.19 2.04 1.8 1.85 1.8 1.95

Table 1. Map units, eruption ages, and volcanic rock names for the Cerros del Rio volcanic field

Map unit

name

Map unit

symbol

Eruptive

series

Eruption age1

(Ma)

Volcanic rock name2

Upper andesite of Cochiti Volcano

Lower andesite of Cochiti Volcano

Basalt of Hill 7033

Andesite of Ortiz Mountain

Basaltic andesite of Twin Hills

Basalt of Hill 7065

Basalt of Tetilla Hole

Basalt of Colorado Peak

Basaltic andesite of Arroyo Eighteen

Basalt of Hill 6929

Basalt of Canada Ancha, upper unit

Basalt of Montoso Peak

Andesite of Colorado Peak

Basalt of La Bajada Rim

Basaltic andesite of Thirty-One Draw

Andesite of Cerrita Portillo

Basalt of Caja del Rio

Basalt of Arroyo Calabasas, lower unit

Basalt of Tsinat Mesa

Basaltic andesite of Cerro Micho

Andesite of Cerro Micho

Andesite of Tetilla Peak

Qcu

Qcl

Qbx

Qo

Qto

Qtd

Qbt

Qcb

Qae

Qbz

Qbu

Tm

Tca

Tb

Ttx

Tcp

Tay

Tbcl

Tbs

Tbc

Tcm

Tat

3

3

2

2

2

2

2

2

2

2

2

1

1

1

1

1

1

1

1

1

1

1

1.51

1.7–1.5

2.03

2.32

2.53

2.55

2.49

2.53

2.56

2.58>Qbz>2.46

2.4>Qbu>2.32

2.59

2.6

>2.6

>2.59

2.61

2.61–2.59

>2.59

2.68

2.73

2.76

3.04

Andesite/trachyandesite

Andesite/basaltic andesite

Basalt

Trachyandesite/trachyte

Basaltic trachyandesite

Basaltic trachyandesite/trachybasalt

Trachybasalt

Trachybasalt

Basaltic trachyandesite

Trachybasalt

Basaltic trachyandesite

Basalt/trachybasalt

Trachyandesite

Basalt/basaltic andesite

Basaltic trachyandesite

Trachyandesite

Trachybasalt

Trachybasalt/tranchyandesite

Trachybasalt/basaltic trachyandesite

Basalt/basaltic trachyandesite

Trachyandesite

Trachyandesite/andesite

1Approximate eruption ages are based on one or more ages where determined for the map area or estimated based on stratigraphic postion. 40Ar/39Ar ages 

for select samples from each map unit are reported in the text. 2Modified root names based on IUGS rock classification (LeBas and Streckeisen, 1991).

Index map showing map area in yellow, and adjacent 7.5-minute 

quadrangles. For U.S. Geological Survey publications the 

publication number, author(s), and year of publication are shown. 

For non-USGS publications the State agency, author, and 

publication year are shown. 

36°52’30”

106°22’30” 106°15’00” 106°07’30” 106°00’00”

36°45’00”

36°37’30”

36°30’00”

FRIJOLES WHITE ROCK HORCADO RANCH

COCHITI DAM MONTOSO PEAK AGUA FRIA

SANTO DOMINGO

PUEBLO

TETILLA PEAK TURQUOISE HILL

GM 73

New Mex. Bureau

of Mines

(Dethier, 1997)

SIM 3179

(Thompson and

others, 2011)

SIM 2896

(Shroba and

others, 2006)

MF 2352

(Sawyer and

others, 2002)

LIST OF MAP UNITS

[Due to the addition of a shaded relief base, colors on the List of Map Units and

Correlation of Map Units may not exactly match unit colors on the map]

SURFICIAL DEPOSITS

Artifical fill deposits

Artificial fill (latest Holocene)

Alluvial deposits

Gravelly alluvium (Holocene? and late Pleistocene)

Sheetwash deposits (Holocene to middle? Pleistocene)

Alluvial and colluvial deposits

Alluvium and colluvium, undivided (Holocene and late Pleistocene?)

Fan alluvium and debris-flow deposits, undivided (Holocene to middle? 

Pleistocene)

Colluvial deposits

Colluvium, undivided (Holocene to middle? Pleistocene)

LAVA FLOWS AND RELATED DEPOSITS OF THE

CERROS DEL RIO VOLCANIC FIELD

El Cajete Member of the Valles Rhyolite (late Pleistocene)

Basaltic alluvium (early? to middle? Pleistocene)

Andesite of Cochiti Volcano (early Pleistocene)

Lower unit

Basalt of Hill 7033 (early Pleistocene)

Andesite of Ortiz Mountain (early Pleistocene)

Basaltic andesite of Twin Hills (early Pleistocene)

Basalt of Hill 7065 (early Pleistocene)

Basalt of Tetilla Hole (early Pleistocene)

Basalt of Colorado Peak (early Pleistocene)

Basaltic andesite of Arroyo Eighteen (early Pleistocene)

Basalt of Hill 6929 (early Pleistocene)

Basalt of Cañada Ancha (early Plesistocene)

Basalt of Montoso Peak (Pliocene)

Andesite of Colorado Peak (Pliocene)

Basaltic andesite of Thirty-One Draw (Pliocene)

Andesite of Cerrita Portillo (Pliocene)

Basalt of Caja del Rio (Pliocene)

Basalt of La Bajada Rim (Pliocene)

Basaltic andesite of Arroyo Calabasas (Pliocene)

Basalt of Tsinat Mesa (Pliocene)

Basaltic tephra and Ancha Formation, undivided (Pliocene)

Basaltic andesite of Cerro Micho (Pliocene)

Andesite of Cerro Micho (Pliocene)

Andesite of Tetilla Peak (Pliocene)

af

Qsw

Qg

Qac

Qba

Qfd

Qc

Qec

Qcu

Qcl

Qbx

Qbt

Qcb

Qto

Qae

Qtd

Qo

Qbz

Qbu

Tm

Ttx

Tca

Tay

Tbcl

Tbs

Tbta

Tcp

Tb

Tbc

Tcm

Tat

af

Qac

Qba

Qsw

? ?

Qfd

?

Qc

?

?

?

Qg Qec

?

Qcuc

Qcl

SURFICIAL DEPOSITS

Artificial-fill

deposits

Alluvial

deposits

Alluvial and

colluvial deposits

Colluvial

deposits

LAVA FLOWS AND RELATED DEPOSITS OF THE CERROS DEL RIO VOLCANIC FIELD

Qcu

R

R

R

Qbxc Qbx

R R

R

R R

R

R

R

2.03 Ma

Tayc Tay N N N N

2.61–2.59 Ma

>2.59 Ma

2.53 Ma

2.58–2.46 Ma

2.4–2.32 Ma

Tbclc Tbcl

N N

Tbsc Tbs

N N Tbta

?

Qtoc Qto

Qbu Qbuc

Tcpc Tcp

Qbzc Qbz

R

R

Qoc Qo 2.32 Ma

R

2.56 Ma Qaec Qae

R R

Qtd Qtdc

Qcbc Qcb

2.55 Ma R R

R

Qbtc Qbt

2.53 Ma

2.49 Ma

N

Ttxc Ttx

2.61 Ma

N

Tcac Tca 2.60 Ma

>2.60 Ma

>2.59 Ma

2.73 Ma

2.76 Ma

3.04 Ma

N N

Tmc Tm

2.59 Ma

Tb

Tbcc Tbc

N N

Tcmc Tcm N N

Tat

N

2.59 Ma

MATUYAMA

Reverse polarity chron

GAUSS

Normal polarity chron

White and black characters represent aeromagnetic polarity signature and paleomagnetic signature respectively. N, normal; R, Reverse.

Approximate eruption ages from table 1.

11.7 ka

132 ka

788 ka

2.59 Ma

late

middle

early

Holocene

Pleistocene

Pliocene TERTIARY

QUATERNARY

CORRELATION OF MAP UNITS

1.7–1.5 Ma

2.68 Ma

1.51 Ma

SCALE 1: 24 000

1 1/ 2 0 1 MILE

1000 1000 0 2000 3000 4000 5000 6000 7000 FEET

1 0 .5 1 KILOMETER

CONTOUR INTERVAL 20 FEET

NATIONAL GEODETIC VERTICAL DATAUM OF 1929 

The geology was mapped from 1997 to 1999 and modified in 2004 to 2008. The primary 

mapping responsibilities were as follows: R. Thompson and M.L. Hudson mapped the 

volcanic deposits and faults and prepared the digital compilation of the geologic map, 

R.R. Shroba mapped the surficial deposits, M.L. Hudson and S.A. Minor mapped surface 

exposures of faults. M.L. Hudson conducted paleomagnetic studies for stratigraphic 

correlations, and D.A. Sawyer assisted with unit correlations with exposures on the APPROXIMATE MEAN adjoining Tetilla Peak quadrangle to the south. DECLINATION, 2010 TRUE NORTH

MAGNETIC NORTH

9°

NEW MEXICO

QUADRANGLE LOCATION

Base from U.S. Geological Survey Montoso Peak, New Mex., 1952, revised 1993

Shaded relief base generated from 10-m Digital Elevation Model (DEM) from the U.S. 

Geological Survey National Elevation Dataset available at http://ned.usgs.gov/.

North American Datum of 1927 (NAD 27)

Projection and 10,000-foot ticks: Universal Transverse Mercator

New Mexico coordinate system, central zone

1,000-meter ticks, Universal Transverse Mercator, zone 13

For more information concerning this publication, contact:

Center Director, USGS Geology and Environmental Change Science Center

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Edit and digital layout by L.J. Binder

Manuscript approved for publication August 31, 2011

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This report is available at:

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CONVERSION FACTORS

Multiply By To obtain

millimeters 0.03937 inches (in.)

centimeters (cm) 0.3937 inches (in.)

meters (m) 3.281 feet (ft)

kilometers (km) 0.6214 miles (mi)

Period or

subperiod

Epoch Age

Quaternary Holocene

Pleistocene

late

middle

early

0–11.7 ka

11.7–132 ka

132–788 ka

788–2.59 Ma

Neogene Pliocene

Miocene

2.59–5.33 Ma

5.33–23.0 Ma

DIVISION OF QUATERNARY AND NEOGENE TIME

USED IN THIS REPORT1

1Ages of time boundaries are those of the U.S. Geological Survey Geologic Names Committee (2010) 

except those for the late-middle Pleistocene and middle-early Pleistocene boundaries, which are 

those of Richmond and Fullerton (1986). Ages are expressed in ka for kilo-annum (thousand years) 

and Ma for mega-annum (million years).

Geologic Map of the Montoso Peak Quadrangle, Santa Fe and Sandoval Counties, New Mexico

By

Ren A. Thompson, Mark R. Hudson, Ralph R. Shroba, Scott A. Minor, and David A. Sawyer

2011

Suggested citation:

Thompson, R.A., Hudson, M.A., Shroba, R.R., Minor, S.A., and Sawyer, D.A., 2011, 

Geologic map of the Montoso Peak quadrangle, Santa Fe and Sandoval Counties, New 

Mexico: U.S. Geological Survey Scientific Investigations Map 3179, 20 p. pamphlet, 1 

sheet, scale 1:24,000. 

Prepared in cooperation with the

National Park Service

Scientific Investigations Map 3179

Pamphlet accompanies Map

U.S. Department of the Interior

U.S. Geological Survey

EXPLANATION

Contact

Normal fault—Dashed where inferred from aerial photographs, dotted where 

concealed; bar and ball on apparent downthrown side

Lineament—Located using aerial photographs and reduced to pole

aeromagnetic map; coincides with zones of minor fracturing and faulting

Cinder deposits—Indicated by a “c” at the end of the unit label

Lava flow direction—Inferred lava flow direction for select volcanic rock 

units

Dike

Inclined bedding—Showing strike and dip

Water well—Approximately located. Showing name and total depth (TD) in 

feet

Sample location—With sample number

30

3MRG–1

U.S. Forest Service

Twelve Hundred Well

TD 1,200