NEW MEXICO BUREAU OF GEOLOGY AND MINERAL RESOURCES A DIVISION OF NEW MEXICO INSTITUTE OF MINING AND TECHNOLOGY Unit Descriptions for the Arroyo del Agua 7.5' quadrangle Cretaceous NMBGMR Open-file Map Series OFGM-124 Cretaceous stratigraphy on the Arroyo del Agua quadrangle follows that of Landis and Last Modified 05 March 2014 Quaternary Dane (1967), Saucier (1974) and Owen et al. (2005). The intertongued Dakota-Mancos Jt Todilto Formation (Middle Jurassic). The Todilto Formation consists of a Qrf Rock Fall (Holocene). Building-sized blocks of Poleo Formation that have succession is referred to here as the Dakota Formation for mapping purposes, because lower, limestone-dominated interval (Luciano Mesa Member, Jt (ls)) overlain locally by broken away from the edge of the sandstone cliff in the recent past (0358913 N 4003825 a gypsum interval (Tonque Arroyo Member; (Jtg) (Lucas et al., 1985, 1995; Kirkland et Py Yeso Group (Early Permian). Orange-red medium-grained, moderately to well- 106°42'30"W 106°40'0"W most of the Dakota members and all of the Mancos members are generally too thin to sorted sandstone with large-scale (eolian) crossbeds, or more rarely, laminated sand sheet 343000 344000 345000 346000 347000 348000 349000 350000 351000 352000 353000 E, NAD 27); the Ponderosa pine trees affected by the fall are dead, but the wood decay al., 1995). The Luciano Mesa Member is 2 to 8 m thick and consists mostly of thinly map separately. Furthermore, the Mancos member that is present (Clay Mesa member) is bedding. These strata are equivalent to the De Chelly Sandstone of the Yeso Group Qal Kd Kbc process is not very advanced. laminated, dark gray or yellowish gray, kerogenic limestone. Beds near the base of the Kbc Kbc 4 7 Qal 5 6 very sandy, so it is treated as a member of the Dakota Formation. Qal Ql 1 Qc 10 Qal Qc (Baars, 1962; Krainer et al. 2005) (Meseta Blanca Member of the Yeso Formation of 2 Qal 8 Qc 7 Qsly Young landslide deposit (Holocene). Unconsolidated, hummocky deposit of member are usually sandy, and microfolding of the thin limestone laminae is common. Kbc Kbc Kbc Kd Kd Dakota Sandstone (Late Cretaceous). (includes Clay Mesa Member of Mancos Northrop and Wood, 1946 ). The eolian sandstone gradationally overlies or is 4 Kbc Kbc Kbc Trassic Salitral Formation shale that slumped downslope in the recent past (350084 N The overlying Tonque Arroyo Member is up to 30 m of white to light gray gypsum Qc Kbc 2 14 Qal Qal Shale, of the intertongued Dakota-Mancos succession). Tan to yellow-brown quartzose interbedded with the arkosic fluvial deposits of the Arroyo del Agua Formation and is 5 Qc Kbc Qc 17 Kd interbedded with carbonate. A thin limestone bed (0.5 to 2.0 m) is deposited on the Qc 4002658 E, NAD 27); vegetation on the deposit is not fully reestablished and Poleo sandstone, dark gray and brown carbonaceous shale, and minor greenish gray mudstone overlain with prominent unconformity by basal strata of the Chinle Group. The unit thins Kd Qc 14 7 Creek is downcutting through the deposit. gypsum of the Tonque Arroyo Member in many places along the Mesa Alta escarpment.. Qc 6 Jm 5 Kbc to the northeast; the line of termination for the unit trends northwest. Along the 3 Kbc Qc Qc and bentonite. Members include, from lowest to highest (oldest to youngest): Encinal Total Todilto Formation thickness is up to 38 m. 6 Kd 2 Qc Qal Alluvium (Holocene). Unconsolidated clay, silt, sand, and gravel deposited in termination, the Yeso Group sand deposits are discontinuous and range in thickness from 3 Kd Kd Kbc 4012000 Canyon, Oak Canyon, Cubero, and Paguate members. The Encinal Canyon Member is Three lithologic relationships are associated with the Tonque Arroyo Member in the Kbc major modern drainages and tributaries; up to 5 m thick. 4 2 Kbc 6 zero to 3 to 5 m, suggesting a facies change to a more fluvial environment toward the Kbc Qc highly variable in thickness, ranging from 0 to 18 m and averaging 2 to 4 m. This tan Arroyo del Agua area: (1) gypsum interbedded with carbonate is preserved (classic 2 Qc Qal Kbc Qes Eolian and alluvial deposits (Holocene). Unconsolidated windblown tan-to- northeast. Up to 20 m thick. 4012000 cross-bedded quartz sandstone, with thin to medium bedding, commonly has woody plant 3 Kbc 7 Qc Kbc Tonque Arroyo Member); (2) a limestone microbreccia left by dissolution the gypsum of Kbc Qal 4 14 brown silt and clay deposited in low-elevation spots and on pediment surfaces. Fluvially 4 impressions at the upper contact. Bioturbation is not common in the Encinal Canyon Qc reworked; contains lenses of gravel. Usually 1 to 3 m thick, but can be 10 m thick. the Tonque Arroyo Member is present; or (3) the Tonque Arroyo member is interbedded Kbc IP-PC Cutler Group (Pennsylvanian-Permian) Qal Kd Sandstone. The fine- to medium-sized sand grains are subangular to subround and well- with a green to red medium-grained quartz sandstone in two places along the escarpment 6 Kbc Kbc Qc Colluvium (Holocene). Hillslope colluvial deposits composed of pebble to We assign the oldest siliciclastic red beds in the Chama Basin to the Cutler Group. Lucas Jm Kbc boulder size, unconsolidated debris derived from local volcanic and sedimentary rocks. sorted. The Oak Canyon Member is a black, muddy siltstone interbedded with thin (<1 (344730 4009647, 347100 4009590). Thus, the Todilto Formation in the vicinity of and Krainer (2005) divided Cutler strata into two, mappable lithostratigraphic units, the Qt 5 Qc Kbc 2 Qal Kbc Kbc 2 Jm m) beds of ledgy and often lenticular, white to orange, cross-bedded, bioturbated Kd Kbc Kbc Kbc Qcbt designates colluvium composed mainly of Bandelier Tuff. Qc refers to colluvium Arroyo del Agua contains a record of places where gypsum was deposited and is still El Cobre Canyon and Arroyo del Agua formations. Several lithologic criteria allow the Jm 5 1 Qc 4 Js made up of a variety of lithologies. Up to 35 m thick. sandstone. The Cubero Member is a white, massive, thick-bedded, bioturbated preserved, areas where the gypsum was deposited, but has since dissolved away, and two formations to be distinguished: Jm Ql Kbc Kbc Kbc Kbc Qls Jtg sandstone that is 7-8 m thick. The Clay Mesa Member (of the Mancos Shale) is black places where the gypsum is interbedded with clastic shoreline deposits. A chaotic breccia Contrasting features of the El Cobre Canyon and Arroyo del Agua formations. Qc Kd 2 3 Qtn Terrace deposits (middle Pleistocene to Holocene). Alluvial silt, sand, cobble, Kbc 4 Jm 000 Kbc 2 70 4011 and boulder deposits of rounded to subrounded local Mesozoic sandstone and well- sandy shale to shale with thin (2-3 cm) beds of ripple-laminated sandstone that is 1-3 m that contains angular blocks up to 1 m across is often preserved along the contact Qc Kbc 6 Pca Arroyo del Agua Formation (Early Permian) -- Orange siltstone, 7 Jm Qc thick. The Paguate Member is orange to tan, with fine-to medium- grained, subangular, between the limestone microbreccia and overlying basal Summerville sandstone. The 4011000 Jm 5 Qal rounded Proterozoic quartzite recycled out of older (Permian Cutler Group or Miocene arkosic sandstone and minor intraformational and extraformational conglomerate. The Kbc Qal Qal Qc Kbc 5 ^cu Abiquiu Formation) deposits. The two highest terraces contain 10 to 20% Pedernal Chert well-sorted sand grains. The Paguate Sandstone is often intensely bioturbated, but in breccia can contain blocks of: (1) basal Summerville sandstone only; (2) blocks of Kd 6 siltstones are thick, slope-forming units with abundant calcrete nodules between thin Qal Qc Kbc Js Summerville sandstone and limestone mircrobreccia; or (3) blocks of Summerville Kd Qc derived from the Miocene Abiquiu Formation. At least three terrace levels (1= oldest, 3 = places remnant cross-bedding, ripple marks, and thin to thick bedding is preserved. It sandstone sheets that are arkosic and trough crossbedded. Up to 130 m thick. 11 Jm youngest) are present along the Rio Puerco and Salitral Creek, one at 49 m, one at 36 m, forms a bold cliff along exposed escarpments of Mesa Alta and is 25-30 m thick. The sandstone and the gypsum-capping limestone. The timing of brecciation post-dates the IPPce El Cobre Canyon Formation (Late Pennsylvanian-Early Permian). Qls 6 Qc Kbc and one at 12 m above modern grade. 1 to 3 m thick. Dakota Sandstone is 40 to 56 m thick. lithification of both the limestone and the sandstone, as well as the microbreccia-forming Brown siltstone, sandstone and extraformational conglomerate that overlies Proterozoic Kd Jm Kd ^cu Jm Jm 5 dissolution event. basement in the subsurface and is conformably overlain by the Arroyo del Agua 6 Qc Qpn Pediment gravels (middle Pleistocene to Holocene). Unconsolidated deposits 4 4 Jm Qe Kd Jm 2 Jm Formation. Siltstone beds of the El Cobre Canyon Formation contain numerous rhizoliths Kbc 64 Kbc of angular to subangular pebbles to boulders of Mesozoic sandstone, limestone and Kbc Burro Canyon Formation (Early Cretaceous). White, light yellow, orange, and 6 Jm Kbc Kbc Qls gypsum resting on surfaces graded to the level of the highest terraces (1= oldest, 3 = and comprise relatively thin, slope-forming units between multistoried sandstone beds Qc Jm Jm Js 4010000 buff, conglomeratic sandstone with thin lenses of pale green and pink mudstone (Saucier, Kd Kbc Jm 2 Jm 3 youngest. The largest surface, covering several km , is on Poleo Mesa, which is cut on Je Entrada Sandstone (Middle Jurassic).