Relict slope rings and talus flatirons in the Colorado Piedmont: Origin, chronology and paleoenvironmental implications

Gutiérrez, Francisco; Morgan, Matthew L.; Matthews, Vincent; Gutiérrez, Mateo; Jiménez‐Moreno, Gonzalo

doi:10.1016/j.geomorph.2014.11.024

Cited by 15 publications

(18 citation statements)

References 47 publications

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“…Changeover from cold/wet to warm/dry conditions probably facilitated the switch from depositional to erosional conditions below the cuesta, consistent with the findings of previous talus flatiron studies (Gutierrez et al . , ). Apron incision rates (1.1–2.5 mm yr ‐1 at the northern site and >2.8 mm yr ‐1 at the southern site) were partially controlled by local base level as transverse stream incision rates accelerated.…”

Section: Discussionmentioning

confidence: 99%

“…Although very few chronologies have been assembled at present, many suggest a strong temporal correlation between talus flatiron formation and late Quaternary climate changes. Apron deposition is generally favored during cold and wet periods, while incision and abandonment occur during warm and dry intervals (Gutierrez et al ., , ).…”

Section: Previous Workmentioning

confidence: 97%

“…A path to quantitative evaluation of cuesta evolution emerged from the debris aprons and their associated landforms. Talus flatirons, triangular slope facets whose upper reaches have been disconnected from the cuesta, have long been recognized on several continents (Koons, 1955;Ahnert, 1960;Schmidt, 1980;Gerson, 1982;Gutiérrez-Elorza and Martinez, 2001;Boroda et al, 2011;Gutiérrez-Elorza et al, 2013;Gutiérrez et al, 2015). Each flatiron has two stratigraphic components: an underlying bedrock foundation and a thin overlying mantle of apron colluvium.…”

Section: Previous Workmentioning

confidence: 99%

“…While some aprons are active depositional settings, others have been dissected by gullies and disconnected from the escarpment, quarantining them from sediment sources and creating relict surfaces called talus flatirons. These landforms have been recognized since the mid‐20th century (Koons, ; Ahnert, ), and yet only in recent years have a small number of flatiron sequences been quantitatively dated (Gutiérrez et al ., , ; Gutiérrez‐Elorza and Martinez, ; Boroda et al ., , ; Gutiérrez‐Elorza et al ., ; Roque et al ., ). Though they are few in number, some available datasets reveal a link between talus flatiron formation and global climate (Gutiérrez et al ., , ), demonstrating that numerically dated flatirons can be used both to quantify rates of cuesta evolution and interpret the driving mechanisms.…”

Section: Introductionmentioning

confidence: 99%

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Late Pleistocene talus flatiron formation below the Coal Cliffs cuesta, Utah, USA

Sheehan

Ward

2018

Earth Surf Processes Landf

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Cuesta escarpment retreat is a principal mode of exhumation in regions of layered sedimentary rock. On the Colorado Plateau, this process acts as a mechanism for maintaining high‐relief topography and facilitating drainage divide migration. Quantitative estimates of cuesta evolution are difficult to evaluate over glacial‐interglacial timescales, and thus rates of geomorphic change along individual escarpments have mostly been constrained over millions of years. Several studies have addressed this problem by dating colluvium‐mantled talus flatirons. However, this technique has not been applied systematically on the Colorado Plateau. This study quantifies geomorphic change along a single Colorado Plateau cuesta using 36Cl surface exposure dating. We present 33 ages from a single generation of talus flatirons below the Coal Cliffs of central Utah. Landscape evolution is further constrained using 14 ages from in‐situ bedrock, 3 ages from boulders on gully interfluves, and two ages from terrace alluvium. Results suggest a colluvial apron was deposited below the cuesta beginning as early as Marine Isotope Stage 3, and the latest depositional phase occurred near the Last Glacial Maximum. A switch from apron deposition to incision initiated flatiron formation sometime between 19.7 ± 2.5 and 11.8 ± 1.6 ka, broadly coincident with the transition from glacial to interglacial conditions. Our results have several important implications. Climatic changes during the end of the last glacial period appear to have shifted the balance between deposition and erosion below the Coal Cliffs, emptying the sediment reservoir at their base and increasing their height via bedrock incision. The climatic forcing could be imparted by several mechanisms, including local controls on debris generation / mobilization and base level changes exerted by transverse streams. Similar processes may have occurred during previous glacial‐interglacial transitions, implying that the escarpment retreat processes may be partially modulated by orbitally‐controlled variations in Earth's climate over larger timescales. Copyright © 2018 John Wiley & Sons, Ltd.

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Section: Discussionmentioning

confidence: 99%

Section: Previous Workmentioning

confidence: 97%

Section: Previous Workmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Late Pleistocene talus flatiron formation below the Coal Cliffs cuesta, Utah, USA

Sheehan

Ward

2018

Earth Surf Processes Landf

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“…Gully and rill incision on cuesta slopes help facilitate this process and track orbitally paced climate changes (Gutiérrez et al, , ). This climatic relationship may reflect variations in the balance between sediment production, deposition, and erosion on cuesta slopes, and numerical age data sets from talus flatiron deposits support this interpretation (Boroda et al, ; Elorza & Martínez, ; Gerson, ; Gutiérrez et al, ; Gutiérrez‐Elorza et al, ; Schmidt, ).…”

Section: Introductionmentioning

confidence: 89%

Migrating Transverse Escarpments in Strike Valleys on the Colorado Plateau

Sheehan

Ward

2020

JGR Earth Surface

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Erosion in strike valleys separating parallel cuesta escarpments controls the evolution of staircase‐like landscapes developed in layered rocks. We explore an important erosional process in strike valleys developed in the Mancos Formation of central Utah, USA. These shale‐floored valleys are segmented by transverse (strike‐perpendicular) scarps, which we call migrating transverse escarpments (MTEs). The MTEs separate axial stream networks that join larger transverse rivers from gullies that drain across adjacent sandstone layers. The MTEs mark a state of transience within the strike valleys as the axial stream networks expand along strike and adjust the gullies to a new base level at the transverse rivers. Here, we describe MTE morphology, consider the geomorphic processes that control their evolution, discuss their impacts on regional landscape evolution using field relationships, and explore how variable geologic parameters may affect their behavior using numerical simulations. Our simulation results suggest that fluvial pour points through the adjacent hard layers serve as internal base levels that modulate MTE evolution. Once a stable axial stream network forms, new MTEs cannot form until the channel network reroutes through the hard layers. This likely occurs over glacial‐interglacial timescales as debris deposition reroutes channel networks and variable hydrologic conditions accelerate transverse river incision. However, our results also suggest that MTEs can form autogenically as downdip strike valley retreat causes the lower hard layer to migrate underneath the axial stream. Our findings highlight the influence of lithologically controlled base levels on landscape evolution, particularly in regions of variable layered rocks.

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Geochronological and paleoenvironmental reconstruction of colluvial deposits in a cuesta landscape in south‐eastern Brazil

Pinton

Lupinacci

2021

J Quaternary Science

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The classic models of cuesta evolution in south‐eastern Brazil have temporal gaps in their denudation chronology. Here, we analyzed the colluvial deposits located on the rim of the Serra Geral escarpments in the Paraná Basin to propose a model with an absolute age range of minor landform evolution within this cuesta morphology. Correlation of the optically stimulated luminescence ages with the regional paleoclimatic conditions demonstrates that the successive phases of colluviation reflect either short‐term intervals of variability in moisture availability or dry periods in the Holocene. The potential effects of other contributing factors (vegetation changes, local geomorphic settings and human activity) add complexity to the denudation responsible for the development of the investigated geomorphic chronosequences. The proposed model consists of five stages of hillslope sediment remobilization that were responsible for further remodeling of the minor vertical steps during the following chronological distribution: (i) 9.13 ± 1.2–7.09 ± 0.96 ka; (ii) 5.66 ± 0.86–4.5 ± 0.75 ka; (iii) 3.94 ± 0.605–3.45 ± 0.6 ka; (iv) 2.66 ± 0.315–2.3 ± 0.4 ka; and (v) after 1960 to the present day.

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Relict slope rings and talus flatirons in the Colorado Piedmont: Origin, chronology and paleoenvironmental implications

Cited by 15 publications

References 47 publications

Late Pleistocene talus flatiron formation below the Coal Cliffs cuesta, Utah, USA

Late Pleistocene talus flatiron formation below the Coal Cliffs cuesta, Utah, USA

Migrating Transverse Escarpments in Strike Valleys on the Colorado Plateau

Geochronological and paleoenvironmental reconstruction of colluvial deposits in a cuesta landscape in south‐eastern Brazil

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