Weathering under coastal hyperaridity – Late Quaternary development of spectral, textural, and gravelometric alluvial fan surface characteristics

Abstract The Rio Grande rift hosts a remarkable record of Quaternary river incision preserved in an alluvial terrace sequence that has been studied for more than a century. However, our understanding of Rio Grande incision history in central New Mexico since the end of basin filling ca. 0.78 Ma remains hampered by poor age control. Robust correlations among Rio Grande terrace sequences in central and southern New Mexico are lacking, making it difficult to address important process-related questions about terrace formation in continental-scale river systems. We present new age controls using a combination of 40Ar/39Ar, 36Cl surface-exposure, and 14C dating techniques from alluvial deposits in the central New Mexico Socorro area to document the late Quaternary incision history of the Rio Grande. These new age controls (1) provide constraints to establish a firm foundation for Socorro basin terrace stratigraphy, (2) allow terrace correlations within the rift basin, and (3) enable testing of alternative models of terrace formation. We identified and mapped a high geomorphic surface interpreted to represent the end of basin filling in the Socorro area and five distinct, post–Santa Fe Group (ca. 0.78 Ma) alloformations and associated geomorphic surfaces using photogrammetric methods, soil characterization, and stratigraphic descriptions. Terrace deposits exhibit tread heights up to 70 m above the valley floor and are 5 to >30 m thick. Their fills generally have pebble-to-cobble bases overlain by fine-to-pebbly sand and local thin silt and clay tops. Alluvial-fan terraces and associated geomorphic surfaces grade to former valley levels defined by axial terrace treads. Carbon-14 ages from detrital charcoal above and below a buried tributary terrace tread show that the most recent aggradation event persisted until ca. 3 ka during the transition from glacial to modern climate conditions. Drill-log data show widespread valley fill ∼30 m thick that began aggrading after glacial retreat in northern New Mexico and southern Colorado (ca. 14 ka). Aggradation during this transition was likely due to hillslope destabilization, increased sediment yield, decreased runoff, and reduced stream competence. Chlorine-36 ages imply similar controls on earlier terraces that have surface ages of ca. 27–29, 64–70, and 135 ka, and suggest net incision during glacial expansions when increased runoff favored down-cutting and bedload mobilization. Our terrace chronology supports existing climate-response models of arid environments and links tributary responses to the axial Rio Grande system throughout the central Rio Grande rift. The terrace chronology also reflects a transition from modest (60 m/m.y.) to rapid (300 m/m.y.) incision between 610 and 135 ka, similar to patterns observed throughout the Rio Grande rift and the western United States in general.

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Late Quaternary rapid talus dissection and debris flow deposition on an alluvial fan in Syria

CATENA ◽

10.1016/s0341-8162(03)00112-7 ◽

2004 ◽

Vol 55 (2) ◽

pp. 125-140 ◽

Cited By ~ 10

Author(s):

Takashi Oguchi ◽

Chiaki T. Oguchi

Keyword(s):

Debris Flow ◽

Late Quaternary ◽

Alluvial Fan

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Mid-Wisconsinan eolian deposits of the Kittigazuit Formation, Tuktoyaktuk Coastlands, Northwest Territories, Canada

Canadian Journal of Earth Sciences ◽

10.1139/e17-116 ◽

1997 ◽

Vol 34 (11) ◽

pp. 1421-1441 ◽

Cited By ~ 24

Author(s):

Scott R. Dallimore ◽

Stephen A. Wolfe ◽

John V. Matthews Jr. ◽

Jean-Serge Vincent

Keyword(s):

Mass Spectrometry ◽

Late Quaternary ◽

Surface Characteristics ◽

Radiocarbon Dates ◽

Glacial Ice ◽

Alluvial Sediments ◽

Summer Climate ◽

Eolian Deposits ◽

Glaciogenic Sediments ◽

Grain Surface

The Kittigazuit Formation is a late Quaternary sand unit commonly observed throughout the Tuktoyaktuk Coastlands and in subbottom sediments of the southern Beaufort Shelf. Stratigraphic and sedimentology data, including sedimentary structures, grain-surface characteristics, and heavy and light mineralogy, assist in characterizing the deposit and indicate that it is eolian in origin. Plant and arthropod macrofossils suggest that, although the summer climate during deposition was as warm or slightly warmer than today, conditions were likely more arid. Permafrost is interpreted as being widespread during deposition. Accelerator mass spectrometry radiocarbon dates indicate that the Kittigazuit Formation was deposited between 37 and 33 ka BP. The unit is therefore interpreted as a Mid-Wisconsinan eolian dune deposit, formed by reworking of underlying alluvial sediments of the Kidluit Formation under nonglacial conditions. Glaciogenic sediments overlying the Kittigazuit Formation indicate that glacial ice covered the Tuktoyaktuk Peninsula, Richards Island, and parts of the Beaufort Shelf sometime after 33 ka BP, whereas several terrestrial dates indicate that the area may have been ice free by about 20 ka BP.

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The linkage between hillslope vegetation changes and late-Quaternary fluvial-system aggradation in the Mojave Desert revisited

Earth Surface Dynamics Discussions ◽

10.5194/esurfd-2-181-2014 ◽

2014 ◽

Vol 2 (1) ◽

pp. 181-213

Author(s):

J. D. Pelletier

Keyword(s):

Vegetation Cover ◽

Mojave Desert ◽

Process Model ◽

Late Quaternary ◽

Drainage Density ◽

Alluvial Fan ◽

System Response ◽

Vegetation Changes ◽

Fluvial System ◽

Extreme Storm

Abstract. Valley-floor-channel and alluvial-fan deposits and terraces in the southwestern US record multiple episodes of late Quaternary fluvial aggradation and incision. Perhaps the most well constrained of these episodes took place from the latest Pleistocene to the present in the Mojave Desert. One hypothesis for this episode, i.e. the paleo-vegetation change hypothesis (PVCH), posits that a reduction in hillslope vegetation cover associated with the transition from Pleistocene woodlands to Holocene desert scrub generated a pulse of sediment that triggered a primary phase of aggradation downstream, followed by channel incision, terrace abandonment, and initiation of a secondary phase of aggradation further downstream. A second hypothesis, i.e. the extreme-storm hypothesis, attributes episodes of aggradation and incision to changes in the frequency and/or intensity of extreme storms. In the past decade a growing number of studies has advocated the extreme-storm hypothesis and challenged the PVCH on the basis of inconsistencies in both timing and process. Here I show that in eight out of nine sites where the timing of fluvial-system aggradation in the Mojave Desert is reasonably well constrained, measured ages of primary aggradation and/or incision are consistent with the predictions of the PVCH if the time-transgressive nature of paleo-vegetation changes with elevation is fully taken into account. I also present an alternative process model for PVCH that is more consistent with available data and produces sediment pulses primarily via an increase in drainage density (i.e. a transformation of hillslopes into low-order channels) rather than solely via an increase in sediment yield from hillslopes. This paper further documents the likely important role of changes in upland vegetation cover and drainage density in driving fluvial-system response during semiarid-to-arid climatic changes.

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Distinct phases of eustatism and tectonics control the late Quaternary landscape evolution at the southern coastline of Crete

10.5194/esurf-2016-62 ◽

2016 ◽

Author(s):

Vasiliki Mouslopoulou ◽

John Begg ◽

Alexander Fülling ◽

Daniel Moraetis ◽

Panagiotis Partsinevelos ◽

...

Keyword(s):

Landscape Evolution ◽

Late Quaternary ◽

Eastern Mediterranean ◽

Vertical Movement ◽

Tectonic Uplift ◽

Alluvial Fan ◽

Contributing Factors ◽

River Incision ◽

Coastal Landscapes ◽

Uplift Rates

Abstract. The extent to which climate, eustacy and tectonics interact to shape the late Quaternary landscape is poorly known. Alluvial fans often provide useful indexes that allow decoding the information recorded on complex coastal landscapes, such as those of Eastern Mediterranean. In this paper we analyse and date (using optically stimulated luminescence – OSL) a double alluvial-fan system in Crete, an island straddling the forearc of the Hellenic subduction margin, in order to constrain the timing of, and quantify the contributing factors to, its landscape evolution. The studied alluvial system is unique because each of its two juxtaposed fans records individual phases of alluvial and marine incision, providing, thus, unprecedented resolution in the formation and evolution of its landscape. Specifically, our analysis shows that the fan sequence at Domata developed during the last glaciation (Marine Isotope Stage 3; 57–29 kyr) due to five distinct stages of marine transgressions and regressions and associated river incision, as a response to climatic changes and tectonic uplift at rates of ~ 2.2 mm/yr. Comparison of our results with published tectonic uplift rates from Crete shows, however, that vertical movement on Crete was minimal during 20–50 kyr BP and mot uplift was accrued during the last 20 kyr. This implies that eustacy and tectonism impacted on the landscape at Domata over mainly distinct time-intervals (e.g. sequentially and not synchronously), forming and preserving the coastal landforms, respectively.

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Luminescence dating Hajar Mountain alluvial fan systems, northern Oman

10.5194/egusphere-egu21-2325 ◽

2021 ◽

Author(s):

Sam Woor ◽

Julie Durcan ◽

Ash Parton ◽

David Thomas

Keyword(s):

Late Quaternary ◽

Alluvial Fan ◽

Luminescence Dating ◽

Modern Humans ◽

Temporal Complexity ◽

Human Dispersal ◽

Palaeoenvironmental Change ◽

Anatomically Modern Humans ◽

Out Of Africa ◽

Scale Data

The alluvial/fluvial fan systems of northern Oman act as sensitive geoproxy records of Late Quaternary palaeohydrology and past landscape evolution, offering records of palaeoenvironmental change which cannot be reconstructed from nearby speleothem records alone (Parton et al., 2013). These systems also provide evidence for the important link between the changing abundance of freshwater in the Arabian interior and the dispersal of anatomically modern humans (AMHs) out of Africa (Rosenberg et al., 2012). Limited previous luminescence dating analyses have reported fan activation west of the Hajar during insolation maxima and monsoon intensification throughout the Late Quaternary (Parton et al., 2015). However, there are currently no studies to date which present chronologies for the fan systems to the east of the Hajar Mountains.We present the first luminescence based chronology for the fan systems to the east of the Hajar Mountains, providing landform scale data on fan behaviour, including spatial-temporal complexity and variability. This facilitates comparison of the temporal response of fans east and west of the mountains, including differential responses to external forcing. Ages will also be compared with regional palaeoenvironmental and palaeoclimatic records, to inform landscape reconstructions in northern Oman during the late Quaternary.ReferencesRosenberg, T.M., Preusser, F., Blechschmidt, I., Fleitmann, D., Jagher, R. and Matter, A., 2012. Late Pleistocene palaeolake in the interior of Oman: a potential key area for the dispersal of anatomically modern humans out&#8208;of&#8208;Africa?.&#160;Journal of Quaternary Science,&#160;27(1), pp.13-16.Parton, A., Farrant, A.R., Leng, M.J., Schwenninger, J.L., Rose, J.I., Uerpmann, H.P. and Parker, A.G., 2013. An early MIS 3 pluvial phase in Southeast Arabia: climatic and archaeological implications.&#160;Quaternary International,&#160;300, pp.62-74.Parton, A., Farrant, A.R., Leng, M.J., Telfer, M.W., Groucutt, H.S., Petraglia, M.D. and Parker, A.G., 2015. Alluvial fan records from southeast Arabia reveal multiple windows for human dispersal.&#160;Geology,&#160;43(4), pp.295-298.&#160;

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Relict sheetflood bed forms on late Quaternary alluvial-fan surfaces in the southwestern United States

Geology ◽

10.1130/0091-7613(1985)13<512:rsbfol>2.0.co;2 ◽

1985 ◽

Vol 13 (7) ◽

pp. 512 ◽

Cited By ~ 37

Author(s):

Stephen G. Wells ◽

John C. Dohrenwend

Keyword(s):

United States ◽

Late Quaternary ◽

Alluvial Fan ◽

Southwestern United States ◽

Bed Forms

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Quaternary paleoenvironmental change preserved in alluvial fans systems in semiarid to arid mountain areas: Examples from western Mongolia, western USA, and the Chilean Andes

10.5194/egusphere-egu2020-3893 ◽

2020 ◽

Author(s):

Frank Lehmkuhl ◽

Veit Nottebaum ◽

Janek Walk ◽

Georg Stauch

Keyword(s):

Late Quaternary ◽

Alluvial Fan ◽

Sediment Supply ◽

Latitudinal Gradients ◽

Alluvial Fans ◽

Mountain Areas ◽

Mountain Ranges ◽

Western Mongolia ◽

Semi Arid ◽

Chilean Andes

Alluvial fans represent complex landforms with the potential to record past environmental conditions. However, their decryption is difficult as their formation depends on a broad set of influences (catchment properties, climate, accommodation space, base level change). A comparison of alluvial fans in three (semi)arid regions aims to illuminate dominant controls on alluvial fan evolution.Large scale alluvial fans in the semiarid to arid mountain areas of western Mongolia, southwestern USA, and the northern part of the Chilean Andes are controlled by different sediment supply. Geomorphological processes in these mountain ranges vary along altitudinal and latitudinal gradients and, additionally, due to climatic change during the late Quaternary. Alluvial fans in Mongolia (Gobi Altai and Mongolian Altai) are mainly formed during the Pleistocene. Higher terraces and alluvial fan generations can be dated to the penultimate glacial cycle. Sheet flow dominated as alluvial fan constructing process during the last Glacial. Since the late Glacial, debris flow accumulation and Holocene incision occurred (Lehmkuhl et al. 2018). Quaternary alluvial fans in mountain areas of the southwestern United States develop in three major settings related to the availability and nature of sediment transport. These include alluvial fans that develop in: i) glaciofluvial settings, ii) areas of tectonic uplift, and iii) regions dominated by periglacial processes. There is evidence for Pleistocene periglacial activity throughout the mountain ranges of the American Southwest in different elevations (L&#246;hrer, 2008). Frost weathering in periods of higher moisture produces debris in the catchment areas and, thus, primarily governs the sediment supply of alluvial fans during the Pleistocene. In the semiarid Andes of northern Chile, alluvial fans form in similar glaciofluvial as well as fluvial settings in elevations above ~4000 m asl.A comparison between these three (semi)arid systems shows that the main fluvial activity occurred during cold and semihumid phases of the Pleistocene resulting in an altitudinal lowering of periglacial processes, thus leading to a higher sediment supply. In addition, in all these regions higher lake levels occurred during the transition from glacial to interglacial periods, e.g. from the Pleistocene to the Holocene. Moister conditions during the transitions control the interplay between lake level variations and the fluvial activity.Lehmkuhl, F., Nottebaum, V., H&#252;lle, D. (2018): Aspects of late Quaternary geomorphological development in the Khangai Mountains and the Gobi Altai Mountains (Mongolia). Geomorphology 312:24-39. https://doi.org/10.1016/j.geomorph.2018.03.029L&#246;hrer, R. (2008): Reliefanalyse an Schwemmf&#228;chern und Fu&#223;fl&#228;chen S&#252;dwesten der USA. Dissertation an der Fakult&#228;t f&#252;r Georessourcen und Materialtechnik der RWTH Aachen, September 2008. Online Ver&#246;ffentlichung der RWTH Aachen: http://darwin.bth.rwth-aachen.de/opus3/volltexte/2008/2504/

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OSL dating of the late Quaternary slip rate on the Gyaring co Fault in central Tibet

Geochronometria ◽

10.1515/geochr-2015-0040 ◽

2016 ◽

Vol 43 (1) ◽

pp. 162-173 ◽

Cited By ~ 1

Author(s):

Duo Wang ◽

Gong-Ming Yin ◽

Xu-Long Wang ◽

Chun-Ru Liu ◽

Fei Han ◽

...

Keyword(s):

Tibetan Plateau ◽

Late Quaternary ◽

Slip Rate ◽

Strike Slip ◽

Alluvial Fan ◽

Osl Dating ◽

The Tibetan Plateau ◽

Slip Rates ◽

Absolute Age ◽

Central Tibet

Abstract The Gyaring Co Fault (GCF) is an active right-lateral strike-slip fault in central Tibet that accommodates convergence between India and Asia in the interior of the Tibetan Plateau. The average long-term slip rate of the fault remains controversial, given the absence of absolute age data of faulted geomorphic features. We have applied optically stimulated luminescence (OSL) dating to the northern segment of the GCF, revealing that the GCF has displaced alluvial fans at Aerqingsang by 500 ± 100 m since their deposition at ~109 ka, yielding a slip rate of 4.6 ± 1.0 mm/yr. A slip rate of 3.4 ± 0.4 mm/yr is inferred from analysis of an alluvial fan with an offset of 65 ± 5 m (~19 ka) at Quba site 1. The Holocene slip rate is estimated to be 1.9 ± 0.3 mm/yr, as inferred from the basal age (~8.3 ka) of terrace T1 that has a gully displacement of 16 ± 2 m at Quba site 2. These slip rates are generally lower early estimates (10–20 mm/yr), but are consistent with more recent results (2.2–4.5 mm/yr) and GPS data for other strike-slip faults in this region, indicating that deformation may be distributed across the entire Tibetan Plateau. Moreover, we suggest that the slip rate along the GCF may have decreased slightly during the late Quaternary.

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