Holocene landscape evolution and geoarcheology of low-order streams in the Rio Grande basin, San Juan Mountains, Colorado, USA

2014 ◽  
Vol 82 (2) ◽  
pp. 331-341 ◽  
Author(s):  
Daniel P. Carver ◽  
Jared M. Beeton
Keyword(s):  
Landscape Evolution ◽  
Research Area ◽  
Alluvial Fan ◽  
San Juan ◽  
Drainage Basins ◽  
Alluvial Deposits ◽  
Geomorphic Mapping ◽  
San Juan Mountains ◽  
Rio Grande Basin ◽  
Alluvial Terraces

AbstractThis geoarcheological study investigates soil stratigraphy and geochronology of alluvial deposits to determine Holocene landscape evolution within the Hot Creek, La Jara Creek, and Alamosa River drainage basins in the San Juan Mountains of Colorado. Geomorphic mapping and radiocarbon dating indicate synchronicity in patterns of erosion, deposition, and stability between drainage basins. In all three basins, the maximum age of mapped alluvial terraces and fans is ~ 3300 cal yr BP. A depositional period seen at both Hot Creek and the Alamosa River begins ~ 3300 to 3200 cal yr BP. Based on soil development, short periods of stability followed by alluvial fan aggradation occur in the Alamosa River basin ~ 2200 cal yr BP. A period of landscape stability at Hot Creek before ~ 1100 cal yr BP is followed by a period of rapid aggradation within all three drainages between ~ 1100 and 850 cal yr BP. A final aggradation event occurred between ~ 630 and 520 cal yr BP at La Jara Creek. These patterns of landscape evolution over the past ~ 3300 yr provide the framework for an archeological model that predicts the potential for buried and surficial cultural materials in the research area.

SOILS AND GEOARCHAEOLOGY OF THE UPPER RIO GRANDE BASIN, SAN JUAN MOUNTAINS, COLORADO

2016 ◽  
Author(s):  
Kelley Jane Ivers ◽  
◽  
Jared M. Beeton ◽  
Jacqueline A. Smith ◽  
Bradley G. Johnson
Keyword(s):  
Rio Grande ◽  
San Juan ◽  
San Juan Mountains ◽  
Rio Grande Basin ◽  
Upper Rio Grande

Timing and distribution of alluvial fan sedimentation in response to strengthening of late Holocene ENSO variability in the Sonoran Desert, Southwestern Arizona, USA

2010 ◽  
Vol 73 (3) ◽  
pp. 425-438 ◽  
Author(s):  
Steven N. Bacon ◽  
Eric V. McDonald ◽  
Todd G. Caldwell ◽  
Graham K. Dalldorf
Keyword(s):  
Sonoran Desert ◽  
Late Holocene ◽  
Southern Oscillation ◽  
Climatic Variability ◽  
Alluvial Plain ◽  
Alluvial Fan ◽  
Alluvial Deposits ◽  
Geomorphic Mapping ◽  
Precipitation Record ◽  
Precipitation Records

The integration of geomorphic mapping, soil stratigraphy, and radiocarbon dating of alluvial deposits offers insight to the timing, magnitude, and paleoclimatic context of Holocene fan sedimentation near Yuma, Arizona. Mapping of 3400 km2 indicates about 10% of the area aggraded in the late Holocene and formed regionally extensive alluvial fan and alluvial plain cut-and-fill terraces. Fan deposits have weakly developed gravelly soils and yielded a date of 3200–2950 cal yr BP from carbonized wood. Alluvial plain deposits have weakly developed buried sandy soils and provided a date of 2460–2300 cal yr BP from a terrestrial snail shell. Precipitation records were analyzed to form historical analogues to the late Holocene aggradation and to consider the role of climatic variability and extreme hydrologic events as drivers of the sedimentation. The historical precipitation record indicates numerous above-average events correlated to the Southern Oscillation Index (SOI) in the region, but lacks any significant reactivation of alluvial fan surfaces. The timing of aggradation from 3200 to 2300 cal yr BP correlates well with other paleoclimatic proxy records in the southwestern U.S. and eastern Pacific region, which indicate an intensification of the El Niño-Southern Oscillation (ENSO) climatic pattern and rapid climate change during this period.

GEOMORPHOLOGY OF TERRACES AND MORAINES IN THE UPPER RIO GRANDE BASIN, SAN JUAN MOUNTAINS, COLORADO, USA

2016 ◽  
Author(s):  
Clifton Simmons ◽  
◽  
Cory Ott ◽  
Jared M. Beeton ◽  
Bradley G. Johnson ◽  
...  
Keyword(s):  
Rio Grande ◽  
San Juan ◽  
San Juan Mountains ◽  
Rio Grande Basin ◽  
Upper Rio Grande

The Northern Rio Grande Basin

1995 ◽  
Author(s):  
William L. Graf
Keyword(s):  
New Mexico ◽  
Stream Flow ◽  
Drainage Basin ◽  
Rio Grande ◽  
San Juan ◽  
San Juan Mountains ◽  
Rio Grande Basin ◽  
Main River ◽  
Generate Surface ◽  
Northern Rio Grande

In northern New Mexico, the environmental plutonium bound to sedimentary particles is the most mobile in river systems, particularly the Rio Grande. This chapter describes the physical characteristics of the drainage basin into which Los Alamos National Laboratory has released plutonium. I review those characteristics of the basin that most strongly influence the movement of sediment and its associated plutonium: landforms, geology and soils, climate, vegetation, and precipitation. Precipitation and elevation provide the energy that is the primary driving force behind river processes in the Northern Rio Grande Basin. The geographic variation in stream flow and the temporal characteristics of its magnitude and frequency explain how water, sediment, and contaminants such as plutonium move through the system. An accurate accounting of stream flow is therefore essential to the development of a basinwide budget for water, sediment, and contaminants. Calculations for the mechanics of sediment transport (and the transport of associated contaminants) thus depend on measurements of stream flow from a variety of places within the system. In this chapter I examine the basic data for stream flow in the basin and then define and explain the temporal and geographical variation in the system’s river flows. The result is a regional stream-flow budget. The portion of the Northern Rio Grande emphasized in this book consists of the watershed upstream from the U.S. Geological Survey stream gage on the Rio Grande at San Marcial, at the headwaters of Elephant Butte Reservoir. The drainage network in this 71,700-sq-km area is the principal mechanism for the surface transport and storage of plutonium. The Rio Grande begins as a trickle of meltwater from a semipermenant snowbank at Stoney Pass in the San Juan Mountains in southwestern Colorado. Steep mountain tributaries are the primary sources of water, joining the main stem as it trends southeastward to the San Luis Valley and the Alamosa, Colorado, area. Additional mountain waters from the Rio Conejos, which drains the southern San Juan Mountains in southern Colorado, join the main stream as it flows southward into New Mexico. The northern Sangre de Cristo Mountains in Colorado generate surface runoff, but relatively little reaches the main river.

Post-glacial landscape response to climate variability in the southeastern San Juan Mountains of Colorado, USA

2011 ◽  
Vol 76 (3) ◽  
pp. 352-362 ◽  
Author(s):  
Bradley G. Johnson ◽  
Martha Cary Eppes ◽  
John A. Diemer ◽  
Gonzalo Jiménez-Moreno ◽  
Anthony L. Layzell
Keyword(s):  
Late Holocene ◽  
San Juan ◽  
Geomorphic Mapping ◽  
San Juan Mountains ◽  
Rapid Changes ◽  
Landscape Response ◽  
Headwater Basins ◽  
Second Period ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractGeomorphic mapping in the upper Conejos River Valley of the San Juan Mountains has shown that three distinct periods of aggradation have occurred since the end of the last glacial maximum (LGM). The first occurred during the Pleistocene–Holocene transition (~ 12.5–9.5 ka) and is interpreted as paraglacial landscape response to deglaciation after the LGM. Evidence of the second period of aggradation is limited but indicates a small pulse of sedimentation at ~ 5.5 ka. A third, more broadly identifiable period of sedimentation occurred in the late Holocene (~ 2.2–1 ka). The latest two periods of aggradation are concurrent with increases in the frequency of climate change in the region suggesting that Holocene alpine and sub-alpine landscapes respond more to rapid changes in climate than to large singular climatic swings. Soil development and radiocarbon dating indicate that hillslopes were stable during the Holocene even while aggradation was occurring in valley bottoms. Thus, we can conclude that erosion does not occur equally throughout the landscape but is focused upslope of headwater streams, along tributary channels, or on ridge tops. This is in contrast to some models which assume equal erosion in headwater basins.

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