sign in sign up
<<
Home , Yeso Group

NEW MEXICO BUREAU OF GEOLOGY AND MINERAL RESOURCES A DIVISION OF INSTITUTE OF MINING AND TECHNOLOGY NMBGMR Open-file Geologic Map 233 Last Modified August 2013

CORRELATION OF MAP UNITS Santa Fe

106°45'00"W 340000 341000 342000 42'30" 344000 345000 346000 40'00" 347000 348000 349000 350000 106°37'30"W 34°22'30"N 34°22'30"N Mass Alluvium Fans from Los Pinos — Gravels contain abundant Pyaa Qay Qay Qsx Qac QTsps Qac Qsfp Qac wastage Mountains Qsx Qsx composition from the subangular, locally derived clasts of the distal Palo Duro fan facies. The most distinctive clasts are Qay Qsfp QTsps Qay Qac Qfm Tib Qsfp Qay Qsfp Qat obsidians from Rabbit Mountain (Jemez Mountains; 1.4 Ma) and Grants (East Grants Ridge, 3 Ma). The unit is poorly Qsfp exposed. Unit is 0-4 m thick. Qac Qfm Qfp Qsx Qao Qac Qay Qsfl Qfi Holocene Fe Group, lower ) — Pale gray (10YR 7/1 to 8/1) poorly consolidated, uncemented, poorly sorted proximal to Qac Qao Qsfp Qsfp Qsfp deposits to west. Clasts are all limestone and 3804000 QTsps Qac Qfm chert from the . Pedogenic carbonate horizon reaches Stage II. Fan is deeply incised by drainage to Qay Qam Palo Duro Canyon on the southwest side, and is moderately incised by drainages to the northeast. Includes more than one 000 Qsfp Qsfp 3804 surface level in proximal part of fan and base is on gray limestone of cuesta. Distal parts of fan are largely eolian sand with Qac Qfp QTsps Qsfp clasts of limestone. Thickness reaches 10 m exposed in canyon. Qay Qsfp Qao Sierra Ladrones Formation, coarse-grained fan deposits spread by ancestral Palo Duro drainage (upper , Qsfp lower Pleistocene) — Pink to reddish-yellow (7.5YR 6/6-7/3), poorly consolidated, uncemented to locally well cemented, Tlp Qfp Qao poorly to moderately sorted conglomerate and pebbly sand. Bedding follows planar, west and northwestward sloping Ttr af upper surfaces with extensive desert pavement; clasts include subangular to subrounded pebbles to boulders of rocks

Quaternary Qto Qsfp QTsps Qsfpo Qfm QTsps Qac Qsfp 000 Qay 3803 leistocene et al. 1986) range in Qac P diameter to more than 1 m. Map unit is inset below older fan deposits (Tsfp and Qsfpo), and locally exhibits terrace-like 000 3803 af Qsx Qsfpo 10 m. QTsps af

QTsps Xglp? Qsfp af Qsfpo CENOZOIC Qac QTsps QTsps Qac Qac Qay Photo 3. Pyaa); view to southwest

liocene from Cibola Canyon drainage (341905E 3791576N). Note that dikes are resistant to erosion at stream level but Qsfp QTsps P Tsfp weather more than enclosing higher on slopes. 3802000 Igneous Qac

Qfm Tp Rocks 3802000 QTsps Qsfp

Qay Qsfpo Spears Formation (upper ) — Light gray and light brownish gray volcaniclastic conglomerates, sandstones, siltstones Qfp Tlp Tsp Qsfp and reddish mudstones derived from intermediate-composition volcanic highlands, primarily to southwest of Joyita Hills, with auxiliary local sources. Subrounded to subangular dacite and andestite porphyry clasts range from boulders Qac Ttr to pebbles; they are common in lenticular to tabular 1-3m thick conglomeratic beds. Dacitic clasts are characterized by Qac Sedimentary sparse to abundant phenocrysts of plagioclase, hornblende and biotite; andesitic clasts are typically plagioclase-pyroxene QTsps Qfi Rocks Tim Tib aleogene

Qay P Tsp Tspa Tspa particularly where they overlie San Andres outcrops on the La Joya quadrangle to the west (de Moor et al., 2005). 3801000 Eocene Andesitic lava within Spears Formation — Medium gray and purplish gray andesite exposed in small area within Tsp. Tsfp Tspa 3801000 af Ku Qsfp Cret. MESOZOIC Jm Qay A Tsfp Qsfp Qfp Qsfp ^c Qac Tsfp MESOZOIC 20'00" Qsfp 20'00" Cretaceous (undivided) (Upper Cretaceous) — Because of the small size of surface exposures in the map area and possible ^m Ku structural complications, Cretaceous rocks are not subdivided on the map. The Cretaceous rocks were deposited within and 3800000 Photo 1. Exposure of Sierra Ladrones Formation, Palo Duro fan deposits (Qsfp) along northern edge of Palo in proximity to the Western Interior Seaway of North America during three major transgressive-regressive cycles (see Hook, QTsps Qac Qac stage III soil, and stage III-IV calcic soil horizon at the surface. Shovel on upper left surface is 1 m long for 1983; Hook et al., 2012, for summary papers). Strata include fossiliferous marine , shale and minor limestone, as 3800000 39 1 Pat Qac Pg Pylv well as non-marine clastic deposits. Shale units are poorly exposed in the Becker SW quadrangle; sandstones are generally 15 ^m scale. View is to north-northeast from 341162E 3799990N (all UTM coordinates are NAD27 13S). Qac Qac Ku D U Tsfp 34 QTsps Psa Qay Ku Ku Pylv Pylv 9 Sierra Ladrones Formation, elevated remnants of coarse-grained fan deposits spread by ancestral Palo Duro drainage System in the area includes, in ascending order, the main body of the Dakota Sandstone (~20 m thick just to the south of the Qto 8 Tsp Qac Qao Qsfpo Qat 33 Tsfp (upper Santa Fe Group, lower Pleistocene) — Pink to reddish-yellow (7.5YR 6/6-7/3), poorly consolidated, uncemented to quadrangle; see also Hook and Cobban, 2007), lower part of the (~ 160 m), Tres Hermanos Formation (~ 73 Pylv Qfi 26 Qac Psa Pg m), D-Cross Tongue of the Mancos Shale (~ 61 m), Gallup Sandstone (~ 42 m), and the Crevasse Canyon Formation (~ 28 m) Qao Pg Qao Tsfp locally well cemented, poorly to moderately sorted conglomerate and pebbly sand. Surfaces exhibit degraded and brecciated Qao 3 Qsfp Qsfp Qay Pg Qac petrocalcic blocks with local desert pavement; clasts include subangular to subrounded pebbles to boulders of rocks from (thickness of units are from a composite section for Sevilleta National Wildlife Refuge by Hook et al., 2012, Fig. 6). Thus, the Pg Pylv 3 Qao Qao Cretaceous System in the area is on the order of 403 m thick. The small exposures of Cretaceous sandstone that are present 23 5 Pylv Pylv Tsp 13 Qac Qay12 8 ermian Pg 000 3799 P of the Mancos Formation, which together bracket the three major transgressive-regressive eustatic cycles Qay 8 3 Qac Pylv Pyaa is not exposed. Map unit is inset below older fan deposits (Tsfp). Thickness estimated from elevations above surrounding Qao U D in the region. 24 Qsfp Pg 8 10 Qsfp on the order of a few meters. Tspa Qac 8 Qao 000 Qay 2 *gm 3799 Ku 34 18 Pylv Pa Sierra Ladrones Formation, sandstone- and mudstone-dominated piedmont deposits (upper Santa Fe Group, lower Ku Psa Qsfp U Pg Pylv Qao Qac 8 Pylv D Qsfp QTsps Qfp Pleistocene to ) — Reddish-yellow (5YR 6/6), unconsolidated to poorly consolidated, uncemented to cemented, Qac Qac Pylv Qac ALEOZOIC Qac Qsfp Pylv Jurassic Qao Xglp P Qsfp 47 23 Qao ^c conglomeratic sandstone lenses exposed along Palo Duro Canyon west of “Five Points.” Beds commonly form upward- Qay ^c *b Qao ^c Qsfp 33 15 Pylv Qac Qac 24 ^m Pylv 19 Ku Pylv thin rhizoconcretionary beds, and cemented tufa-like spring-groundwater-precipitated deposits. Sandstone beds tend to (Upper Jurassic) — Fine- to medium-grained litharenite and intercalated greenish mudstone to *a Jm sandy siltstone. Sandstones (some multi-story) generally weather dark brown to yellowish brown in blocky ledges, are 42 Qsfp Pg 10 anian comprise less than 30% of the unit. Thickness ranges from 0 to more than 20 m. 54 23 Qac 12 4 16 ^m 6 ^m Tsfp l v 6 *gm Sierra Ladrones Formation, elevated remnants of coarse-grained fan deposits spread by ancestral Palo Duro drainage wood. Conglomerates locally contain an abundance of limestone clasts. Mudstone intervals are typically greenish-gray Pylv 21 ^m 000 Tsfp ^c Qsfp 9 17 3798 — Pink to reddish-yellow (7.5YR 6/6-7/3), poorly consolidated, locally well Pylv Qao ^c Pat 11 41 Xglp (upper Santa Fe Group, lower Pliocene) and covered. Hayden et al. (1990) suggested that the Morrison Formation is probably present in the map area; based on 19 Qsfp ^m Pat 12 9 cemented, poorly to moderately sorted conglomerate and pebbly sand. Surfaces exhibit degraded but thick brecciated 15 enns y the lithology, stratigraphic position, and overall appearance of the deposits in comparison with other Morrison outcrops 000 Qsfp Qac 6 *s Igneous and

3798 Qac P 3 Qam Pat in central New Mexico, assignment to the Morrison Formation for these rocks is reasonable. Exposures in cuestas south of ^m 7 Metamorphic (2011); clasts include subangular to subrounded pebbles to boulders of rocks from the southern Los Pinos Mountains, 9 U Pg Pat Qay Gibbs Place suggest thicknesses of at least 60 m. ^c ^m ^m Psa D 20 ^c Qsfp Rocks Qsfp Qsfp ^c 2 Qac NO basalt, basaltic andesite, or rhyolite. The lack of 3.51-Ma basalt clasts and the stage V-VI petrocalcic horizon at the surface D Pat 7 ^m ^m U 33 Tim Qat suggest that this deposit is older than 3.5 Ma. Basal contact with underlying older bedrock is exposed along the north side of 34 ^m 17^m Qay Qay Xglp 23 5 Triassic Qac ^c Pat Qsfp Qao Xglp Palo Duro Canyon near “Five Points” where the thickness estimated to be approximately 10 m. Small exposures of Miocene ^m 5 ^c Qac Ku Qac 22 Pat Qsfp Qao 23 D U 27 Psa 12 PROTERO. Qsfp Qsfp Pat 20 Qsfp U D Qao ^m aleo-

P Canyons are lumped into this unit. Qac 43 ^m 29 Qac Psa ^c ^c 20 Chinle Group (undivided; Upper Triassic) — Upper Triassic rocks in the region include the basal Shinarump and the ^m Qao 20 ^c Qac 13 ^c 24 23 Qac Pat 24 000 ^c 54 20 ^c 16 3797 overlying San Pedro Arroyo formations of the Chinle Group (see Lucas [1991] for a summary of Triassic stratigraphy in Qac ^c U ^c Tp ^c Qao ^c D 12 Qfp Fe Group, Miocene) Qac Qao ^m ^c Jm Pat Pg 23 south-central New Mexico). Only two small outcrops of probable Shinarump strata, less than 2 m thick, were encountered 31 ^c 13 ^c Qac 20 3797000 ^m 10 Tim 23 DESCRIPTION OF MAP UNITS andesite, granite, and Paleozoic-Mesozoic sandstones and limestones. Upper surface exhibits degraded but thick brecciated during mapping; therefore, the Chinle Group is not subdivided on the map. The small outcrops of Shinarump that were 36 ^m Qao 24 Qsfp 19 Qac 18 Qao ^c ^c Pat Qay 22 petrocalcic blocks with partially dissolved boulders and cobbles of limestone. West side of paleovalley is cut through 15 Qao D 12 12 17 Tim ^c 19 ^c Jm ^m 27 U Qay ^c 29 ^m13 6 Pylv Qao Qao Qsfp Xglp 33 21 Qac source not from the southern Los Pinos Mountains, but perhaps from outliers similar to Turututu to the north. The thickness Qao Qao 25 Pg Qac reddish-brown to purplish-gray and greenish mudstone and shale (with some bentonitic layers), lesser siltstone, limestone, ^c ^m 17 CENOZOIC 32 Qac 23 11 Qac Qac estimated to be approximately 15 m. Tim 25 17 Tp 16 Qac 10 and minor reddish-brown sandstone. Pebble-conglomerate sands containing an abundance of limestone clasts were Qac ^c ^c ^m 42 Qac 23 U Qao 2 observed in a few small outcrops. The distinctive Ojo Huelos Member of the San Pedro Arroyo Formation, characterized ^c Jm Psa Qac D and Neogene Qay Qsfp Xglp by a vertical succession of brown weathering limestone beds up to a few meters thick, and intervening meter-scale intervals D Qao 20 Qfi Qfi Qay Qao U Pat ^c ^c Qac Pyaa of siliciclastic muds that are commonly yellowish to greenish in color, is well represented in the map area. Finer-grained Qao ^c ^m Qay 22 7 siliciclastic muds in the San Pedro Arroyo formation are generally poorly exposed, whereas limestone beds in the Ojo ^m Pg Qac 17 Qac Alluvium 15 ^m 5 3796000 Qao Qat 28Qac21 Qay Qac Qao Pylv Pyaa af Qao 6 14 Pat on the quadrangle, the Chinle Group (except for the limestone beds) is poorly exposed and pervasively folded and faulted, Jm 29 Tim 23 17 3796000 Qay 35 ^c ^m 12 37 10 Modern channel deposits in thalwegs of large drainages (historic) — Poorly to moderately sorted, unconsolidated coarse-grained Qay Qao Pat Qao *s Qat 19 Pat ^m 24 sand with local accumulations of cobbles and small boulders in channels, and silt and clay in backwaters and low point bars and Jm Tp that the Morrison Formation is present within a few meters of the top of the highest limestone bed in the Chinle. In other 25 ^c Psa 21 14 19 Qao B 13 19 Qac D 22 14 areas it seems possible that a greater thickness of Chinle muds may be present above the Ojo Huelos member. Lucas (1991) Qao 25 20 U Qac 18 19 24 4 Qac 39 Qao 20 23 ^m 17'30" 20 25 Jm 15 Qay 25 17'30" streams; channels are inset against low terrace (Qay) and abandoned slightly higher deposits under plains in southwest part of measured a total Chinle thickness of about 37 m on the Becker SW quadrangle, but indicates that the top of the section is a Qao^m Qac *gm 20 ^m Pat 29 22 33 22 ^c 18 21 17 quadrangle (Qam). Includes active alluvium of Palo Duro (a.k.a., Agua Torres and Salas) Arroyo and Cibola Canyons. Deposits fault contact. At the type locality of the San Pedro Arroyo Formation approximately 40 km to the south of the map area, the 26 18 23 Tim 17 15 ^m ^c U 26 Psa 46 D Pylv Qao 20 are generally ephemeral and thin, ranging from less than 1 m to more than 2 m thick. Channel position based on 2005 aerial Qay 9 *gm 18 formation is approximately 120 m thick (Lucas, 1991; Spielmann and Lucas, 2009). Pat Pat Pat Qac Qac 13 Qac 28 Qac 11 *gm photographs. Includes unmapped exposures of bedrock in scoured reaches and adjacent, very low overbank areas. 18 21 Qao 21 Pat Qac 46 51 35 () 20 20 Pyaa ^m 23 31 21 Qsfp 22 22 13 — Poorly to moderately sorted, poorly consolidated pebble- et Qao D 22 ^c Qao 37 Qay Qam U 39 Pat Qac 37 12 40 D U Pylv 3795000 al. (1990) measured approximately 60 m of sandstone exposed on the Becker SW quadrangle. 32 Qay Pylv Qac Qao Qac 16 U D 13 Qac 17 Qay Qac 3795000 29 Mapped adjacent to incised active channels (Qat) and in unincised valleys. Deposits range from at least 1.5 m to more than 7 m Pylv ^m Qsfp Qao thick. 15 Qao Qay A' 52 Qfi PALEOZOIC Qac Qao 15 16 Pat 13 47 Pylv *s 5 Alluvium, undivided deposits at low-intermediate valley-border levels (Holocene to upper Pleistocene) — Poorly consolidated 63 19 15 Qam Qao Pylv 27 sand and gravel adjacent to and beyond modern drainages. These less active, slightly higher deposits are primarily under plains Psa 24 8 Pylv Permian Qat Qac Qao Qao 73 66 in the southwest part of quadrangle. Inset against older alluvium; younger alluvium is inset against Qam. At least two levels noted 31 Psa Qat *gm 8 Qac Qac *a Pg 11 5 adjacent to some drainages, but not mapped separately. Exposed thicknesses less than 10 m. Psa Qay ^m 25 *gm 26 21 Qao 20 75 14 Pyaa Qsfl Psa 33 Artesia Group (Middle Permian) Pat Pylv Qay 13 Qac Alluvium, undivided older deposits (upper to middle Pleistocene) — Moderately consolidated and unconsolidated sand and Pylv 12 Pat 31 Qac Qao sandstone, and yellowish brown dolomite. Sandstone beds commonly exhibit ripple-laminated and planar-laminated Qay 7 Qac Qac gravel associated with sloping valley borders. Gravels are subangular to subrounded pebbles and cobbles of locally derived Pylv 10 4 5 Pylv 000 bedforms. Estimated thickness is 10 to 25 m. 20 Qac 3794 limestone and sandstone, along with granitic, metamorphic, and sparse volcanic rock types derived from reworked deposits from 19 4 25 Qac Pylv U Los Pinos Mountain headwaters. Includes elevated local piedmont-alluvial areas capped by gypsum crust and incised by more 18 D Qay Qac Qay 5 Qac *a San Andres Limestone (Lower Permian) — The bulk of the San Andres is light-gray, brown-gray to pale orange limestone, 23 23 Pylv Qac Psa 3794000 16 15 14 af recent drainages north of Gibbs Place. Also includes higher aggraded medial-distal fans elevated above valley alluvium (Qay and Photo 2. Stratigraphic sequence of lower Permian San Andres Formation (Psa) and Artesia Group (Pat), overlain Qay 14 Qac 4 *a Qac Qac Qac Qac 53 Qam). by Triassic Moenkopi Formation (^m). West of a fault buried in the valley, the lower part of the Triassic brown siltstone near middle. Upper beds are cyclic gypsum and thin black limestone beds approximately 40 m thick. Unit 74 22 (^c) overlies the Moenkopi Formation, and is overlain by sandstones and mudstones of Qay Qac Psa Pg Pylv Qao Pylv Qsfp 7 Alluvium, undivided older terrace deposits (middle Pleistocene) — Moderately consolidated sand and gravel associated with thickness ranges from 70 to 160 m according to Myers et al. (1986). Qac Qac Qac Qto the Morrison Formation (Jm Qac 13 Qac Qat Tib Pylv Qac stream terraces along valley borders. Gravels are subangular to subrounded pebbles and cobbles of limestone, sandstone, granitic, (Lower Permian) Qay ^c ^c 83 16 Tp). The upper surface of the Popotosa Pyaa 78 Qac Pg 13 Tib 18 Pylv *a metamorphic, and sparse volcanic rock types indicating derivation from Los Pinos Mountain headwaters. Inset against the Sierra Ku Qam Pg 19 Formation developed a thick petrocalcic horizon with deeply corroded limestone cobbles and boulders. View 7 Jm ^c 26 14 Pylv Tib ^m D U Qac Pylv 18 Tim Pylv Qac *gm Qac Qac 15 Pylv Qac to west-northwest from 342975E 3796392N. (Lower Permian) — Ledge-forming orange sandstone and siltstone; white gypsum; and yellowish-gray 8 Pg Pylv 21 *a 23 Qao 23 7 14 Py Tib Qay 23 Qac Pylv 17 9 Pylv dolomite, limestone and gypsiferous sandstone. Subdivided into two formations after Lucas et al. (2005). Ku ^c 33 Qac Qat Pyaa 36 3 *a 23 15 2 Pylv Tim Qac Pylv Qay Qao 13 Qac Pg Qac 24 Pylv 5 Colluvial deposits Jm ^m Qac D 3793000 Los Vallos Formation (combines Joyita, Cañas, and Torres Members) — Interbedded dolomite, gypsiferous siltstone, Ku Qay Qac Pylv Qay Pylv af Tim Pyaa 15 37 U 5 Qac 21 Pg Qay Qac Pylv Qac Colluvium and alluvium, undivided (Holocene to upper Pleistocene) Qay 16 4 Paleogene Psa Tim Tim 16 10 14 29 Qac Canyon (Wilpolt et al., 1946). 000 Tim Pylv 13 Tim to coarse-grained, clast- and matrix-supported deposits derived from a variety of mass-movement hill-slope processes, including 3793 ^c Tim Tim Qac 16 Pyaa D 6 Pyaa U Qac Qay Pylv Qac 6 *a Arroyo de Alamillo Formation ( equivalent to Meseta Blanca Member) — Pinkish red, to pale orange and yellowish Qao Qay Qac Qto Pyaa Qac Qay *a 6 Clasts are typically rounded to subangular pebbles and cobbles reworked from bedrock and older Quaternary units. Colluvium is C Qac Tim Pylv La Jara Peak Basaltic Andesite, (probably tongue 5, upper Oligocene) — Mostly medium gray to purplish gray, massive Qac 21 U 16 *a Tlp U DKu Ku Tim Tim Qat Pyaa D Tib common on hillslopes and grades downslope to alluvium; both are dissected; thickness ranges from less than 1 m to 5 m. massive) is much less common, and there are a few beds of dolomite and gypsum present. Gradationally overlies the Abo Qac 21 Pg Pylv Qay 10 18 Pylv af 10 Psa Pylv Qac Qac 9 14 10 Formation. Unit is approximately 65 m thick on the quadrangle (Wilpolt et al., 1946). Qay 16 7 Pa Qsfp 13 ^m Qao Qac 19 13 25 D Qao Tim Qay 9 Qat *a U (3-6 m) commonly exhibit vesicular tops and reddish basal breccia zones. Tlp Qac Qac Pyaa Pyaa Qac Qac Pa Tib (Lower Permian) Pylv 15 17 *b Alluvial aprons and fans from the Los Pinos Mountains Pa Ku Qay Pylv 15 Tib Tim Pylv Pa 15 Pg Qac U 14 13 *b 24 Ku Tim Qac D *b 18 Tim 1978). Maximum thickness is 13 m. Pylv D Alluvium deposited on fans debouching from the Los Pinos Mountains, undivided (upper Holocene to upper Pleistocene) — Pylv U Pyaa *b *a Qfp 6 Pylv Pyaa 12 37 Qac B' 23 Tib 23 17 Qto *a — Poorly exposed beneath Tlp 32 4 Qac 3792000 12 U D Qay Qac Qac *b *a Ttr Ku 22 14 19 Qac Qay 26 9 *b of cobbles and small boulders in longitudinal bars, and silt and clay in longitudinal areas of low slope. Includes both active Qac 13 14 on the Cerro Montoso quadrangle just the east of the map area (Myers et al.,1986). Pyaa U 12 8 40 39 Tim Qay D Jm Qac broad shallow channels and interchannel areas. Also includes “whalebacks” of elevated alluvium of older fan remnants. Historic 12 m) (28.4, 28.7, and 32 Ma Ar/ Ar ages respectively; Chapin et al. 000 21 8 *a Qac 3792 Ku ^c Tim Pylv Pylv 14 Qac Qao Qay Pa 14 light brownish gray and light gray, phenocryst poor, pumiceous, rhyolite ignimbrite. Pervasive well developed compaction Tim 8 11 Ku Qac 5 Qac Pylv Qao Tim 7 18 Qac horizons. Deposits range from at least 1.5 m to more than 7 m thick and may be hundreds of meters thick in the subsurface. ^c Tim Pyaa Pyaa Pyaa 27 Qac The large fans of Sepultura and Bootleg Canyons are delineated separately to illustrate their elongate shapes extending into the 7 Pylv Qac 29 Qsfp ^c Pylv 6 Tib Qac Jm 26 Psa Tib 7 Qac southern Albuquerque basin. Qao ^c Qao Jm Qac Pylv Tib 32 D *a Pa *a Qam Qac 21 3 42 ^c D Qay 6 32 67 27 12 Pyaa U C' U Interfan small alluvial aprons from small drainages along the Los Pinos Mountain front (upper Holocene to upper Pleistocene) Qac Qay 12 32 70 Bursum Formation (Upper Pennsylvanian to Lower Permian) Jm D U Pylv Qac Qac *b 29 41 Qao 8 Qac 4 mudstone and shale, reddish- to yellowish-brown sandstone, gray limestone, and minor intraformational (limestone- ^m Pg 5 Qac Qac Pa *a 25 14 Jm Qto Qac ^c 27 Pylv of cobbles and small boulders in longitudinal bars, and silt and clay in longitudinal areas of low slope. Includes both active broad clast) conglomerate beds. Unit represents the transition from dominantly marine (Atrasado Fm.) to terrestrial (Abo Fm.) Qac 18 Qao Pylv 10 *b 1 Psa 16 12 Qao Ku Pylv Pylv Qat Qay 6 U D Pa shallow channels and interchannel areas. Also includes “whalebacks” of elevated older Pleistocene alluvium of older fan remnants Tib ^c 11 64 Qac 6 Basaltic andesite dikes (Oligocene) — Medium to dark gray, olive gray, or dusky yellow basaltic andesite dikes; commonly depositional environments. Limestone beds are commonly fossiliferous, and locally contain an abundance of fusulinid Tim Qac Qac 000 Tim Qac Pg 31 Tib Pyaa Qac Qat 3791 Qfp. Psa 19 Pylv Qao Qsfp Qac Qsfp Qat Qay aphyric (lack phenocrysts) or contain sparse (2-5%) micro-phenocrysts (< 1mm) of greenish olivine. Olivine is often altered e.g., crinoid stems and bivalves). Allen et al. (2013) measured Qao 32 Jm Qac Qac Qay Qao Pa Qac 8 Pa Qat *a *a Qao Psa Pa Pa approximately 40 m of Bursum Formation just south of the map area. 34°15'00"N Pylv Pg Tim Pyaa 34°15'00"N Elevated alluvium and eolian sand and silt previously deposited on medial to distal fan positions debouching from the Los 000 342000 343000 344000 345000 346000 347000 348000 349000 350000 Qfm 106°45'00"W 340 341000 42'30" 40'00" 106°37'30"W Pinos Mountains, undivided (upper Pleistocene) — Poorly to moderately sorted, unconsolidated pebble to cobble alluvium and (Upper Pennsylvanian) Tim *a limestone and intervening intervals dominated by slope-forming greenish gray to reddish brown siliciclastic mudstone, Base map compiled from US Topo, U.S. Geological Survey, 2010. areas of low slope. Includes low-gradient, broad shallow swales and inter-swale uplands. Also includes “whalebacks” of elevated thickness from 1 m to 100 m. siltstone, and calcareous shale. Crossbedded and planar laminated silty sandstone to conglomeratic sandstone including 1983 North American datum reprojected to 1927 North American datum. UTM projection -- zone 13. 1000-meter UTM grid shown in blue. least 1.5 m to more than 7 m thick and may be hundreds of meters thick in the subsurface. yellowish-brown dolomitized limestone beds are present. Ongoing work on the Atrasado in central New Mexico by Lucas 1:24,000 and others (e.g., Lucas et al. MAP SYMBOLS MN 1 0.5 0 1 MILE upper part of the unit locally make the distinction between the upper two limestone-dominated members (Story and Moya members) less certain in the map area. About 240 m thick in the southeastern part of the quadrangle. A A' Location of geologic cross section. GEOLOGIC CROSS SECTIONS BLACK ABEYTAS BECKER BUTTE Gray Mesa Formation (Middle Pennsylvanian) 1000 0 1000 2000 3000 4000 5000 6000 7000 FEET Geologic contact, solid where exposed or known. *gm with minor siliciclastic (calcareous shale and sandstone) interbeds. About 50 m thick on the east edge of the map area, which D ! ! ! A Palo Duro A' is relatively thin compared with exposures to the north in the southern Manzano Mountains (Nelson et al., 2013) where the U NEW MEXICO “D”on downthrown side; “U” on upthrown side. Solid Northwest Canyon Southeast unit is approximately 190 m thick. 1 0.5 0 1 KILOMETER where exposed or known, dashed where inferred, and Salas 6,000 6,000 Sandia Formation (Middle Pennsylvanian) — Ledges of gray, reddish brown to greenish gray, and yellowish brown planar LA JOYA CERRO Arroyo BECKER SW feet ASL Pyaa Qsfp feet ASL *s MONTOSO Psa Jm Pat Psa Qsfp/QTsps Pg Pg Tim laminated and crossbedded sandstone to pebble conglomerate and minor fossiliferous gray to brownish-gray-weathering Low-angle normal fault, half-circles on upper block. ^m Psa Pg Psa limestone, and intervening covered slopes of greenish gray, reddish brown, and yellowish mudstone to silty sandy shale. ^m ^c Pylv CONTOUR INTERVAL 20 FEET Ku ^m Pg 5,000 Jm Pat Psa Pg 5,000 Some sandstone beds contain abundant hematitic woody debris. The deposits are of mixed terrestrial, marginal Tib Pylv Psa Pat Pyaa ^c NORTH AMERICAN VERTICAL DATUM OF 1988 Basaltic dike, unit Tib. ^m Pg marine, and marine origin. About 140 m are exposed on the east edge of the map area at the mouth of Sepultura Canyon, Pyaa *b Pa SIERRA Magnetic Declination Pat Pg MESA DEL SIERRA DE Psa which may be close to the maximum thickness of the Sandia Formation in the area. LARGA *b YESO LA CRUZ July, 2011 Pg Pylv *b Pylv NORTH Rockslide. Pa 09º 08' East 4,000 4,000 Pyaa At Map Center Pyaa *a New Mexico Bureau of Geology and Mineral Resources 4 *b Strike and dip of inclined bedding. Pa *a Pa *b *gm PROTEROZOIC \ 1 Photo location and number. *gm Open-file Geologic Map 233 3,000 Pa *b *gm *s 3,000 QUADRANGLE LOCATION *a *s *a Los Pinos Granite (Paleo-proterozoic) Xglp 2,000 *gm *gm 2,000 Mapping of this quadrangle was funded by a matching-funds grant from the STATEMAP program *s *s Pinos Mountains and in western outlier (Xglp? - unkown if derived from same pluton). Simple pegmatite dikes of similar of the National Cooperative Geologic Mapping Act, administered by the U. S. Geological Survey, *s X composition are common, but pale aplite dikes are uncommon. The south end of the outlier in the NW corner of the and by the New Mexico Bureau of Geology and Mineral Resources, (L. Greer Price, Director X COMMENTS TO MAP USERS X quadrangle consists of breccia of granite, granite gneiss, and amphibolite in blocks up to one meter in diameter. Present top and State Geologist, Dr. J. Michael Timmons, Assoc. Director for Mapping Programs). 1,000 X 1,000 of this exposure contains “cupolas” 3-25 m across and up to 6 m high of intensely metasomatized red granite and pegmatite. X New Mexico Bureau of Geology and Mineral Resources A geologic map displays information on the distribution, nature, orientation, and age relationships of rock and deposits and the occurrence of structural features. Geologic and fault contacts are New Mexico Tech 0 0 radiometric ages of 1653 to 1658 million years (Karlstrom et al., 2004). irregular surfaces that form boundaries between different types or ages of units. Data depicted 801 Leroy Place on this geologic quadrangle map may be based on any of the following: reconnaissance field Socorro, New Mexico geologic mapping, compilation of published and unpublished work, and photogeologic interpretation. 87801-4796 Geologic map of the Becker SW quadrangle, B Salas B' C C' Locations of contacts are not surveyed, but are plo ed by interpretation of the position of a given West Arroyo East West East contact onto a topographic base map; therefore, the accuracy of contact locations depends on the Numerous intra-formational folds and faults 6,000 occur in the gypsiferous Los Vallos Fm. here Tib 6,000 6,000 Cibola 6,000 [575] 835-5490 scale of mapping and the interpretation of the geologist(s). Any enlargement of this map could cause Qsfp Qsfp Canyon Socorro County, New Mexico feet ASL *a feet ASL feet ASL Tib feet ASL Psa ^m Pat Tim misunderstanding in the detail of mapping and may result in erroneous interpretations. Site-specific Pat ^m K ^c Pat ^c Psa Pylv *a ^c ^c Pyaa *gm Psa Pylv Pat ^m Pa *b conditions should be verified by detailed surface mapping or subsurface exploration. Topographic ^m Psa Pylv Pg Pyaa *b ^m Jm Pylv 5,000 *s 5,000 5000 Pat ^c Pyaa 5000 and cultural changes associated with recent development may not be shown. Pg Pa Psa Psa Pylv *s Pg ^m Pa Pyaa *b Pg This and other STATEMAP quadrangles are available June, 2013 Psa Pat *a Pylv *b *a Pylv Pg Pylv for free download in both PDF and ArcGIS formats at: Cross sections are constructed based upon the interpretations of the author made from geologic Pyaa Pa 4,000 Pyaa *b 4,000 4000 *a *gm 4000 mapping, and available geophysical, and subsurface (drillhole) data. Cross-sections should be used as Pyaa Pylv Pyaa Pa *a *gm *b *s an aid to understanding the general geologic framework of the map area, and not be the sole source *a *s Pa Pyaa Pa Pa h p://geoinfo.nmt.edu of information for use in locating or designing wells, buildings, roads, or other man-made structures. *b *gm *s 3,000 3,000 3000 *b 3000 *a *s *b by *a *a *s X The map has not been reviewed according to New Mexico Bureau of Geology and Mineral Resources *gm *gm standards. The contents of the report and map should not be considered final and complete until *gm 2,000 *s 2,000 2000 *gm X 2000 Bruce D. Allen, David W. Love, David J. McCraw, and Alex J. Rinehart reviewed and published by the New Mexico Bureau of Geology and Mineral Resources. The views and X *s *s conclusions contained in this document are those of the authors and should not be interpreted as *s X necessarily representing the official policies, either expressed or implied, of the State of New Mexico, or X 1,000 1,000 1000 1000 New Mexico Bureau of Geology and Mineral Resources, 801 Leroy Place, Socorro, NM 87801 the U.S. Government. X X

0 0 0 0