... composed of volcanic rock. This sand is less common southwest, toward the area where the volcanic member of the Bidahochi is present. Therefore this sand could have been derived only from the volcanic area that lies farther northeast, in the northern part of the Defiance Plateau and Chuska Mountains...

...Figure 2. (A) Digital elevation model for the Chuska Mountains area. Flat top of the southern Chuska Mountains is defined by silica-cemented zones within the Chuska Sandstone that formed during early, phreatic diagenesis (see text). Note the eastern boundary structure of the Laramide Defiance...

... to 1,635 feet; Fruitland formation (coal-bearing), 194 to 292 feet; Pictured Cliffs sandstone, 49 to 275 feet; Lewis shale, 76 to 425 feet; and Mesaverde formation, 1,980 feet. 6 J. W. Harshbarger and C. A. Repenning, “Water Resources of the Chuska Mountains Area, Arizona and New Mexico, “ U. S...

...H. E. WRIGHT, JR.; ANNE M. BENT; BARBARA SPROSS HANSEN; L. J. MAHER, JR. Abstract The Chuska Mountains, with an elevation of 2,700 m above sea level, are covered with a forest of ponderosa pine punctuated by openings around small lakes. Spruce, fir, Douglas-fir, and aspen are found on the north...

... a small dike, (9) south flank of East Sonsela Butte, and (10) southwest corner of Palisades volcanic center. The basal conglomerate is thus distributed over an area at least 45 miles from south to north, and the basal unconformity over the entire extent of the Chuska Mountains. The basal conglomerate...

... derived from basement rocks exposed in the Needle Mountain area of the San Juan Mountains, as is the case with clasts of that age in the Crooked Ridge river alluvium, so this by itself is not unequivocal evidence against derivation of at least some Chuska material from the San Juan Mountains, as pointed...

... components and probably had similar sources, so no material in the Chuska Sandstone was derived from the San Juan Mountains…” This is incorrect as shown by paleocurrent data from the Chuska Sandstone type section in the southeastern Chuska Mountains, where approximately the upper two-thirds of the fluvial...

... beds formerly called the Allison barren member. 4. Despite the impossibility of direct tracing under the cover of younger rocks in the Chuska Mountains, the essential equivalence of the upper part of the Hosta sandstone member in the southern area and of the Point Lookout sandstone in the northern...

... the Defiance monocline ( Fig. 2 ). The Chuska syncline bounds the Toadlena anticline on the southwest and separates it from the Defiance uplift. The Defiance complex defines the San Juan basin on the southwest. Fig. 2. —Regional structure and igneous outcrops in the Dineh-bi-Keyah field area. After...

..., are presented in Figure 3 along with the writers’ correlations. These previous correlations were based on reconnaissance studies which did not permit the detailed tracing of the changes which occur particularly in the area of poor exposures under the Tertiary cap of the Chuska Mountains. The Defiance...

... that Bidahochi streams draining toward the Bidahochi lacustrine tract were working headward into the flank of the Chuska erg, which reached a maximum thickness of >500 m ( Cather et al., 2008 ). Areally restricted exposures of Chuska Sandstone capping the present Chuska Mountains are a surviving erosional...

... Rocky Mountains. For ages different than 10 Ma, elevations are adjusted to 10 Ma using approximate erosion rates or are considered equivalent to 10 Ma elevations if they are in a region where 12–8 Ma denudation was slow or minimal. Figure 2. Topographic image of the study area showing state...

... for quantifying rapid post–2 Ma regional denudation of the Grand Canyon region. Figure 1. Study area in the eastern Grand Canyon region of the southwest Colorado Plateau, northeastern Arizona. Mtn—mountain; Plt.—plateau; Res—reservoir. TABLE 1. KEY LOCALITIES MENTIONED IN THE TEXT TABLE...

... Mesozoic eolianites. The scarcity of eolian sand suggests that the Oligocene Chuska erg of Cather et al. (2008) either was never present in the area traversed by Crooked Ridge River, or was eroded by the time the river was active. At The Gap ( Figs. 2 , 3 , and 4 ), the valley crosses the Echo...

... for typing. © 1968 American Association of Petroleum Geologists. All rights reserved 1968 American Association of Petroleum Geologists The regions within the Four Corners-Intermountain area where exploratory work was concentrated during 1967 included the north flank of the Uinta Mountains...