Distribution and stratigraphy of Upper rocks in the Tijeras Canyon area, central 1Bruce D. Allen, 2Spencer G. Lucas, 3Karl Krainer, 4Filiberto Gomez, 4Mauro Torres, and 4Chris Turren

1New Mexico Bureau of Geology and Mineral Resources, NM Tech, 2New Mexico Museum of Natural History, 3Institute of Geology, University of Innsbruck, Austria, 4GCC Rio Grande Inc., Tijeras, NM

"And all...will readily acknowledge the regularity of the strata from whence our building materials are collected; and masons, miners and quarrymen can identify particular beds of stone dug many miles apart.” —William Smith, collected writings from the period 1796-1799 (Cox, 1942, p. 84). Stratigraphic studies of the Pennsylvanian System in New Mexico and geologic mapping in the Manzanita and included, in 2018, examination of an area south of the village of Tijeras that has produced Portland cement since the late 1950s. Maps of the area were examined and compiled and a complete section of the Pennsylvanian System was measured across the prominent NE-SW trending ridge (“Tijeras hogback”) that extends to the east of I-40 for approximately 5 km south of Seven Springs. Results are summarized in the following illustrations and bulleted text.

Ps Pa Pb Pa Xq C R 38 B 83 Sd B K Ys Kn 40 Pa Cg C RB LK

K Sd R Marcou’s wall Xt Kn

d disturbed B Qac 9 C LK section 28 C K R m unit Informal Units Xc Qac alluvium/colluvium Sd d Pa Kn B ~ Moya top C R RB Cg Kn LK 155 33 12 19 RB Sd Moya Pb 11 RB LK Lime Kiln mbr. C Mbr. Kn Tijeras fault K LK LK RB Pa Abo Fm Kn Qac K LK 230 141 31 Kn Kn Pb A RB Kn 21 Sd Pb R LK B K Pb C R Pa LK LK LK Bursum Fm RB 19 C Kn d RB Qa LK RB 140 Pa B RB K Kn R 13 Kn R Pa Atrasado Fm R RB LK 220 Pb R Kn LK RB Xt Cg RB Kn RB K LK RB Kn R Sd Red Bed mbr. C A C Pg Gray Mesa Fm RB Route 66 K R LK 138 R K Kn B C C Knobby Del Sd Kn 137 Marl Kn LK Seven 12 B LK A 21 Pennsylvanian Ps Sandia Fm* Qa Cuerto Qa B Sd 210 K R Springs Ps R 134 R C Mbr. 16 K A B R K *includes (?) strata Sd R 132 Tijeras Qa LK east of the Tijeras fault zone C RB Kn Kn 131 14 B R K Kn LK Knobby mbr. 23 Sd B MW section Cg 200 130 B Sd R RB RB B R RB Qac Ys Sandia Granite Kn Kn RB K Kn R Kn Cg C RB Kn Qa K R Kn LK A LK R LK R A K Qa RB LK R RB LK K 129 C K R Kn R RB LK RB Kn B Sd Cg RB Qac Xc Cibola Gneiss B RB R Sd C Pg 21 R Cg Kn 127 19 R Kn LK K LK 32 K Kn RB 190 Qa RB Story LK R 125 RB Kn Raindrop mbr. Xq quartzite Kn SD K 14 B R RB R 124 Mbr. K Kn R Kn Kn K RB RB B Sd Tijeras Canyon 29 Xt Tijeras Greenstone LK 26 K 337 C LK Kn R Eon Proterozoic K

R R R 6 B Cg Kn 180 B Sd 119 Xm metasediment Cg Cg Kn Kn LK 25 K Ps B Tijeras hogback R Cg K RB R R R C Kn 117 B Sd Kn Kn S7 section K R 170 B

K C Sd R Xm Kn Kn LIME KILN MEMBER (LK) 113 R L I T H O L O G Y Cg B B Pa Cg R R ALLUVIUM (Qa) S6 section C Kn B Sd RB Kn ABO (A) 22 B R R 160 24 K 111 Ps LIME KILN MEMBER (LK) 15 K Sd 109 17 Cg Kn RED BED MEMBER (RB) Cg B C 19 Kn 23 C KNOBBY MEMBER (Kn) 107 K Burrego Cg Cg KNOBBY MEMBER REMOVED (Kn) Khaki mbr. B R B 105 Mbr. Sd Sd RAINDROP MEMBER (R) B 150 K KHAKI MEMBER (K) 104 C Kn CARBON MEMBER (C)

K Sd Kn 102 R SANDSTONE MEMBER (Sd) Pa Pg B K Corral Canyon Sd K BRACK MEMBER (B) C B 100 C Cg B CONGLOMERATE MEMBER (Cg) Sd Sd Sd 140 B 97 4 drain fault 96 B B Cg 95 contour interval 2 m 94 11 cement plant map 92 130 Cedro Canyon Pg 90 3878 88 FIGURE 3. Historical geologic map of the area fusulinids 86 7 1000 m grid, UTM NAD83 120 84 Syringopora, fusulinids 3 Ps 3 80 71 74 outlined in Figure 2, depicting the distribution of Council Carbon mbr. 77 Spring Mbr. informal lithostratigraphic units utilized by cement 110 76 UTM 1 km grid 74 plant geologists (archival AutoCAD file). fusulinids 70 100 dolomitic mudstone 68 FIGURE 2. Geology of the area shown in Figure 1, calcarenite/crinoidal packstone 66 FIGURE 1. Historical aerial photograph interbedded shale- based on ongoing mapping in the Manzanita and Szabo 6 section mixed siliciclastic- 90 carbonate sandstone 64 of the area south of Tijeras, NM. m unit nodular limestone Sandstone ~ Gray Mesa top Tinajas 140 62 Sandia Mountains. 107 cherty limestone Mbr. (Summit) mbr. 60 limestone 80 103 58 fusulinids (Triticites) pebbly sandstone 55 lithostratigraphic unit Stage 130 The Pennsylvanian section in central NM is assigned to the (ascending) Sandia, Gray Mesa 95 sandstone 54 94 52 and Atrasado formations (e.g., Lucas et al., 2014; Fig. 5), and is approximately 356 meters Bursum Formation Wolfcampian sandy mudstone 70 shale/mudstone Moya Mbr. 87 50 thick (Sandia- 56 m, Gray Mesa- 68 m, Atrasado- 232 m) along the Tijeras hogback (Fig. 4). Virgilian 120 sample 86 Del Cuerto Mbr. 48 fusulinids 60 Story Mbr. 85 (Wedekindellina) 43 Amado As first noted by Szabo (1953), ~20 m of Mississippian (?) redbed siliciclastics and dolomitic 110 80 42 Brack mbr. Burrego Mbr. 79 40 Mbr. 77 Gray Mesa Fm. 50 38 mudstone lie between the and Proterozoic basement along the western 37 Council Spring Mbr. Missourian 73 side of the hogback (Figs. 4, 6). The age of these strata remains speculative—conodonts 100 33 Tinajas Mbr. 68 were not recovered from the dolomite samples that were examined. Hand specimen 40 31 with fossil seed fern 63 30 impressions, from quarry in Amado Mbr. 29 lower Amado (”Brack”) interval 90 The is overlain by the Pennsylvanian-Permian Bursum Formation, which 59

Atrasado Formation (Desmoinesian) of the Atrasado Formation. consists of marine and terrestrial siliciclastic and carbonate facies. Bursum strata are exposed Bartolo Mbr. 30 26 24 52 23 in the vicinity of the village of Tijeras (Fig. 2). Des- Szabo 7 section 80 50 Bartolo Gray Mesa moinesian m unit Conglomerate mbr. 48 20 Mbr. Formation 47 13 34 Gray Mesa Fm. 33 70 11 The Atrasado Formation consists of alternating intervals dominated by slope-forming silici- 70 44 plant stems 31 10 clastics and cliff-forming marine carbonates—these strata are readily assignable to the eight 5 Sandia Formation Atokan 30 29 40 Coyote lithostratigraphic members of the Atrasado presently recognized across central NM (Figs. 4, 5). 60 28 60 3 SS Bed 27 Atrasado Fm. FIGURE 5. Pennsylvanian FIGURE 6. Mississippian? dolomite 32 0 1 Gray Mesa Fm. 26 lithostratigraphic units and below the Sandia Formation, sec- 28 Chaetetes Because the Atrasado provides the raw material for the production of Portland cement, 50 50 26 rugose geologists at the cement plant in Tijeras have long had a practical incentive to characterize approximate ages in the tion Szabo 6 (S6; Fig. 1) on western 24 25 FIGURE 4. Measured sections Sandia Fm. 23 Tijeras area. side of the Tijeras hogback. 22 22 Sandia Fm. and delineate the distribution of Atrasado lithofacies in the area (Figs. 3, 4). The informal sub- 40 40 21 20 of strata along the Tijeras hog- divisions developed by industry geologists are similar to the formal, eight-member subdivisions 17 19 16 18 of the Atrasado Formation shown in Figure 5, thus demonstrating (and echoing the words of 17 back (Sandia, Gray Mesa and 30 30 William Smith quoted above) the ready recognition and utility of these subdivisions in regional 14 15 Atrasado formations). Section stratigraphy, mapping and economic geology. 13 12 20 20 traverses are shown in Figure 1. 10 11 9 Formal and informal divisions 10 9 Mississippian? 10 8 7 Mississippian? 6 of the Atrasado Formation are 3 2 0 0 1 basement 1 basement indicated on the right column.

References

Cox, L.R., 1942, New light on William Smith and his work: Yorkshire Geol. Soc. Proc., v. 25, pt 1, p. 1-99.

Lucas, S.G., Krainer, K., Allen, B.D., and Vachard, D., 2014, The Pennsylvanian section at Cedro Peak: a reference section in the Manzanita Mountains, central New Mexico: New Mexico Geology, v. 36, p. 3-24.

Trough cross-bedded quartz sandstone in the upper part of the Sandia View northward along the western side of the Tijeras hogback, showing cherty Coyote Sandstone Bed (Fig. 4) at the base of Field check of formal vs. informal Moya Member at the top of the Atrasado Formation Formation, measured section S6 (Figs. 1, 4). limestone beds in the Gray Mesa Formation. I-40 is visible in the background. the Bartolo Member of the Atrasado Formation, lithostratigraphic schemes for in abandoned quarry cut. The Moya (a.k.a. “Lime Szabo, E., 1953, Stratigraphy and paleontology of the rocks of the Cedro Canyon area, Manzanita The Gray Mesa Formation is comparatively thin (~68 m) in this area. along the section MW traverse (Fig. 1). Atrasado Formation strata. Kiln” member) has historically been used to produce Portland cement at the plant in Tijeras, NM. Mountains, Bernalillo County, New Mexico [M.S. thesis]: Albuquerque, University of New Mexico, 68 p.