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C.M. Menges

Publications and source records attributed to C.M. Menges.

10 recordsLinked to original sources
USGS2008

Multistage late Cenozoic evolution of the Amargosa River drainage, southwestern Nevada and eastern California Society of America. All rights reserved

Stratigraphic and geomorphic analyses reveal that the regional drainage basin of the modern Amargosa River formed via multistage linkage of formerly isolated basins in a diachronous series of integration events between late Miocene and latest Pleistocene-Holocene time. The 275-km-long Amargosa River system drains generally southward across a large (15,540 km<sup> 2</sup> ) watershed in southwestern Nevada and eastern California to its terminus in central Death Valley. This drainage basin is divided into four major subbasins along the main channel and several minor subbasins on tributaries; these subbasins contain features, including central valley lowlands surrounded by highlands that form external divides or internal paleodivides, which suggest relict individual physiographic-hydrologic basins. From north to south, the main subbasins along the main channel are: (1) an upper headwaters subbasin, which is deeply incised into mostly Tertiary sediments and volcanic rocks; (2) an unincised low-gradient section within the Amargosa Desert; (3) a mostly incised section centered on Tecopa Valley and tributary drainages; and (4) a west- to northwest-oriented mostly aggrading lower section along the axis of southern Death Valley. Adjoining subbasins are hydro-logically linked by interconnecting narrows or canyon reaches that are variably incised into formerly continuous paleodivides. The most important linkages along the main channel include: (1) the Beatty narrows, which developed across a Tertiary bedrock paleodivide between the upper and Amargosa Desert subbasins during a latest Miocene-early Pliocene to middle Pleistocene interval (ca. 4-0.5 Ma); (2) the Eagle Mountain narrows, which cut into a mostly alluvial paleodivide between the Amar-gosa Desert and Tecopa subbasins in middle to late Pleistocene (ca. 150-100 ka) time; and (3) the Amargosa Canyon, which formed in late middle Pleistocene (ca. 200140 ka) time through a breached, actively uplifting paleodivide between the Tecopa and southern Death Valley subbasins. Collectively, the interconnecting reaches represent discrete integration events that incrementally produced the modern drainage basin starting near Beatty sometime after 4 Ma and ending in the Salt Creek tributary in the latest Pleistocene to Holocene (post-30 ka). Potential mechanisms for drainage integration across paleodivides include basin overtopping from sedimentary infilling above paleodivide elevations, paleolake spillover, groundwater sapping, and (or) headward erosion of dissecting channels in lower-altitude subbasins. These processes are complexly influenced by fluvial responses to factors such as climatic change, local base-level differences across divides, and (or) tectonic activity (the latter only recognized in Amargosa Canyon). ?? 2008 The Geological Society of America.

Conference Paper↗
USGS2007

Late Quaternary stratigraphy and luminescence geochronology of the northeastern Mojave Desert

The chronology of the Holocene and late Pleistocene deposits of the northeastern Mojave Desert have been largely obtained using radiocarbon ages. Our study refines and extends this framework using optically stimulated luminescence (OSL) to date deposits from Valjean Valley, Silurian Lake Playa, Red Pass, and California Valley. Of particular interest are eolian fine silts incorporated in ground-water discharge (GWD) deposits bracketed at 185-140 and 20-50 ka. Alluvial fan deposits proved amenable for OSL by dating both eolian sand lenses and reworked eolian sand in a matrix of gravel that occurs within the fan stratigraphy. Lacustrine sand in spits and bars also yielded acceptable OSL ages. These OSL ages fill gaps in the geochronology of desert deposits, which can provide data relevant to understanding the responses of several depositional systems to regional changes in climate. This study identifies the most promising deposits for future luminescence dating and suggests that for several regions of the Mojave Desert, sediments from previously undated landforms can be more accurately placed within correct geologic map units.

Quaternary International↗
USGS2005

Digital method for regional mapping of surficial basin deposits in arid regions, example from central Death Valley, Inyo County, California

Derivative maps generated from DEM's and panchromatic remote sensing data (TM Landsat 7 or SPOT) can be used to characterize surficial basin deposits in arid regions dominated by basin and range topography. Results indicate the technique is useful for rapid digital mapping of surficial deposits where a first order, systematic subdivision of bedrock, alluvial fan units, and playas is unavailable at regional scales. Digital mapping can provide information about relative age and material properties of units that in part can be derived from the position of units within the basin. This automated mapping, implemented in a GIS system, involves an iterative process applied to a combination of digital elevation models (DEM) and satellite image data, such as SPOT or the high-resolution panchromatic Band 8 of Landsat 7 scenes. The method first discriminates the region into first-order terrains consisting of bedrock mountain highlands, basin piedmonts, and playa-basin interiors based on user-defined slope cutoffs applied to DEM data. The basin areas are subsequently classified into surficial map units such as active channels, ground-water discharge zones, and multiple age alluvial-fan piedmont units based on reflective properties of the associated surfaces in the satellite imagery. The surficial units are differentiated through systematic classification based on specific user-defined ranges of spectral values for each unit. The spectral ranges used in the classification are largely dependent on the composite effects of surface characteristics and material properties, including depositional morphology and texture, pavement development, degree of surface clast varnishing, and (or) properties of exposed soils of the alluvial fan units. We have used the slope-curvature properties derived from the DEM data to discriminate the bajada areas that exhibit non-unique spectral characteristics. Slope curvature is particularly effective at differentiating young undissected surfaces from older dissected piedmont units. Available geologic maps and field observations may be used both to iteratively calibrate the spectral classification scheme and to provide additional verification of the digital map output. Digital mapping combined with detailed field studies in selected areas provides useful regional maps of surficial units until time and funding is available for more field intensive studies. In addition, anomalous areas on the thematic maps indicate where more detailed field or air photo work is warranted. The technique successfully distinguishes between bedrock, alluvial fans (generally multiple fan units), active washes, playas, playa rimming marshes and seeps and other active and inactive discharge zones in arid basin and mountain regions. Limitations occur in the subdivision of some fan units where the dominant detrital clast lithologies are not susceptible to varnish development.

California↗
USGS1991

Application of uphole data from petroleum seismic surveys to groundwater investigations, Abu Dhabi (United Arab Emirates)

Velocity data from uphole surveys were used to map the water table and the contact at the base dune sand/top alluvium as part of a joint National Drilling Company-United States Geological Survey Ground Water Research Project in the Emirate of Abu Dhabi. During 1981–1983, a reconnaissance seismic survey was conducted for petroleum exploration in the eastern region of Abu Dhabi. Approximately 2800 kilometers of seismic data, consisting of 92 lines, were acquired in the 2500 km 2 concession area near Al Ain. Uphole surveys were conducted about 2 km apart along each seismic line, and were used to calculate weathering corrections required to further process in the seismic data. Approximately 1300 uphole surveys were completed in the concession area between March 1981 and June 1983. Reinterpretation of the velocity profiles derived from the uphole surveys provided data for determining the following subsurface layers, listed in descending order: (1) a surficial, unconsolidated weathering layer with a velocity from 300 to 450 m/s; (2) surficial dune sand, from 750 to 900 m/s; (3) unsaturated, unconsolidated alluvium, from 1000 to 1300 m/s; and (4) saturated, unconsolidated alluvium, from 1900 to 2200 m/s. Two interfaces—the water table and the base dune sand/top alluvium — were identified and mapped from boundaries between these velocity layers. Although the regional water table can fluctuate naturally as much as 3 m per year in this area and the water-table determinations from the uphole data span a 27-month period, an extremely consistent and interpretable water-table map was derived from the uphole data throughout the entire concession area. In the northern part of the area, unconfined groundwater moves northward and northwestward toward the Arabian Gulf; and in the central and southern parts of the area, groundwater moves westward away from the Oman Mountains. In the extreme southern area east of Jabal Hafit, groundwater moves southward into Oman. The map of the base dune sand/top alluvium suggests a buried paleodrainage network trending westward to southwestward away from the Oman Mountains. These paleodrainages, now buried by dune sand, probably contain alluvial fill and are logical targets for groundwater exploration.

Geoexploration↗