Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-11-23T23:00:12.043Z Has data issue: false hasContentIssue false
  • English
  • Français

Lateral accretion of modern unvegetated rivers: remotely sensed fluvial–aeolian morphodynamics and perspectives on the Precambrian rock record

Published online by Cambridge University Press:  12 May 2016

ALESSANDRO IELPI
ALESSANDRO IELPI*
Affiliation:
Department of Earth Sciences, Laurentian University, Sudbury, ON, P3E 2C6, Canada
*
*E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Modern unvegetated rivers flowing through aeolian-dune fields demonstrate potential as analogues for pre-vegetation fluvial landscapes. A prominent example is contained in the Lençóis Maranhenses of Brazil, a coastal aeolian system hosting the semi-perennial Rio Negro. Remotely sensed images covering c. 45 years display the rhythmic expansion and wind-driven shift of single-threaded and sinuous fluvial trunks alternating with wider braided plains. Sinuous tracts feature mid-channel and bank-attached bars, including expansional point bars with subdued relief. The morphology, accretion and sediment transport of unvegetated point bars in the Rio Negro are compared to the morphodynamics of vegetated meandering rivers. Unvegetated point bars are composed of large coalescent unit bars, lack apparent scroll topography and are preferentially attached to channel banks located on the windward side of the river course. Unvegetated meanders have expansional behaviour related to downwind channel trailing. Point bars maintain an expansional planform despite spatial confinement induced by aeolian dunes. Channel-flow impingement onto cohesion-less banks favours scouring of deep pools along the bar tails, which host bank-collapse deposits subsequently reworked into new bars. Analogies to Precambrian rivers suggest that ancient unvegetated fluvial landscapes were not unequivocally featured by low sinuosity, especially if characterized by a low gradient and stable discharge. This inference is supported by ongoing studies on Proterozoic fluvial–aeolian systems in the Canadian Shield. Lack of scroll topography introduces overlap with low-sinuosity fluvial facies models, underscoring the value of observing ancient fluvial deposits in planform, or along 3D sections where the palaeodrainage of channel bodies and attached bars can be compared.

Keywords

meanderpoint barProterozoicpre-vegetationdesertremote sensingBrazil
Type
Original Articles
Information
Geological Magazine , Volume 154 , Issue 3 , May 2017 , pp. 609 - 624
Copyright
Copyright © Cambridge University Press 2016 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Al-Masrahy, M. A. & Mountney, N. P. 2015. A classification scheme for fluvial–aeolian system interaction in desert-margin settings. Aeolian Research 17, 67–88.CrossRefGoogle Scholar
Allen, J. R. L. 1982. Sedimentary Structures: Their Character and Physical Basis. Developments in Sedimentology vol. 30. Amsterdam: Elsevier, 593 pp.Google Scholar
Andrews, E. D. 1984. Bed material entrainment and the hydraulic geometry of gravel-bed rivers in Colorado. Geological Society of America Bulletin 95, 371–8.2.0.CO;2>CrossRefGoogle Scholar
Bartholdy, J. & Billi, P. 2002. Morphodynamics of a pseudomeandering gravel bar reach. Geomorphology 42, 293–310.CrossRefGoogle Scholar
Bhattacharya, J. P., Payenberg, T. H. D., Lang, S. C. & Bourke, M. 2005. Dynamic river channels suggest a long-lived Noachian crater lake on Mars. Geophysical Research Letters 32, L10201.CrossRefGoogle Scholar
Bluck, B. J. 1974. Structure and directional properties of some valley sandur deposits in southern Iceland. Sedimentology 21, 533–54.CrossRefGoogle Scholar
Bridge, J. S. 1993. Description and interpretation of fluvial deposits: a critical perspective. Sedimentology 40, 801–10.CrossRefGoogle Scholar
Buck, S. G. 1983. The Saaiplaas Quartzite Member: a braided system of gold- and uranium-bearing channel placers within the Proterozoic Witwatersrand Supergroup of South Africa. In Modern and Ancient Fluvial Systems (eds Collinson, J. D. & Lewin, J.), pp. 549–62. International Association of Sedimentologists, Special Publication 6.CrossRefGoogle Scholar
Bullard, J. E. & McTanish, G. H. 2003. Aeolian–fluvial interactions in dryland environments: examples, concepts and Australia case study. Progress in Physical Geography 27, 471–501.CrossRefGoogle Scholar
Burge, L. M. & Smith, D. G. 1999. Confined meandering river eddy accretions: sedimentology, channel geometry and depositional processes. In Fluvial Sedimentology VI (eds Smith, N. D. & Rogers, J.), pp. 113–30. International Association of Sedimentologists, Special Publication 28.CrossRefGoogle Scholar
Cant, D. J. & Walker, R. G. 1978a. Fluvial processes and facies sequences in the sandy braided South Saskatchewan River, Canada. Sedimentology 25, 625–48.CrossRefGoogle Scholar
Cant, D. J. & Walker, R. G. 1978b. Development of a braided-fluvial facies model for the Devonian Battery Point Sandstone, Québec. Canadian Journal of Earth Sciences 13, 102–19.CrossRefGoogle Scholar
Castro, A. C. L. & Piorski, N. M. 2002. Plano de Manejo do Parque Nacional dos Lençóis Maranhenses, Contexto Regional. Instituto Chico Mendes de Conservação da Biodiversidade, 40 pp.Google Scholar
Church, M. 2002. Geomorphic thresholds in riverine landscapes. Freshwater Biology 47, 541–57.CrossRefGoogle Scholar
Cotter, E. 1978. The evolution of fluvial style, with special reference to the central Appalachians Paleozoic. In Fluvial Sedimentology (ed. Miall, A. D.), pp. 361–84. Canadian Society of Petroleum Geologists, Memoir 5.Google Scholar
Davies, N. S. & Gibling, M. R. 2010. Cambrian to Devonian evolution of alluvial systems: the sedimentological impact of the earliest land plants. Earth-Science Reviews 98, 171–200.CrossRefGoogle Scholar
Eaton, B. C. & Giles, T. R. 2009. Assessing the effect of vegetation-related bank strength on channel morphology and stability in gravel-bed streams using numerical models. Earth Surface Processes and Landforms 34, 712–24.CrossRefGoogle Scholar
Eriksson, P. G., Bumby, A. J., Brümer, J. J. & van der Neut, M. 2006. Precambrian fluvial deposits: enigmatic palaeohydrological data from the c. 2–1.9 Ga Waterberg Group, South Africa. Sedimentary Geology 190, 25–46.CrossRefGoogle Scholar
Eriksson, P. G., Condie, K.C., Tirsgaard, H., Mueller, W. U., Altermann, W., Miall, A. D., Aspler, L. B., Catuneanu, O. & Chiarenzelli, J. R. 1998. Precambrian clastic sedimentation systems. Sedimentary Geology 120, 5–53.CrossRefGoogle Scholar
Ethridge, F. G., Tyler, N. & Burns, L. K. 1984. Sedimentology of a Precambrian quartz pebble conglomerate, southwest Colorado. In Sedimentology of Gravels and Conglomerate (eds Koster, E. H. & Steel, R. J.), pp. 165–74. Canadian Society of Petroleum Geologists, Memoir 10.Google Scholar
Fairén, A. G., Stokes, C., Davies, N. S., Schulze-Makuch, D., Rodríguez, J. A. P., Davila, A. F., Uceda, E. R., Dohm, J. M., Baker, V. R., Clifford, S. M., McKay, C. P. & Squyres, S. W. 2014. A cold hydrological system in Gale Crater, Mars. Planetary and Space Science 93–94, 101–18.CrossRefGoogle Scholar
Fernández-Remolar, D. C., Morris, R. V., Gruener, J. E., Amils, R. & Knoll, A. H. 2005. The Río Tinto Basin, Spain: mineralogy, sedimentary geobiology, and implications for interpretation of outcrop rocks at Meridiani Planum, Mars. Earth and Planetary Science Letters 240, 149–67.CrossRefGoogle Scholar
Fralick, & Zaniewski, K. 2012. Sedimentology of a wet, pre-vegetation floodplain assemblage. Sedimentology 59, 1030–49.CrossRefGoogle Scholar
Fuller, A. O. 1985. A contribution to the conceptual modeling of pre-Devonian fluvial systems. Transactions of the Geological Society of South Africa 88, 189–94.Google Scholar
Gay, G. R., Gay, H. H., Gay, W. H., Martinson, H. A., Meade, R. H. & Moody, J. A. 1998. Evolution of cutoffs across meander necks in Powder River, Montana, USA. Earth Surface Processes and Landforms 23, 651–62.3.0.CO;2-V>CrossRefGoogle Scholar
Ghinassi, M. 2011. Chute channels in the Holocene high-sinuosity river deposits of the Firenze Plain, Tuscany, Italy. Sedimentology 58, 618–42.CrossRefGoogle Scholar
Ghinassi, M. & Ielpi, A. 2015. Stratal architecture and morphodynamics of downstream-migrating fluvial point bars (Jurassic Scalby Formation, UK). Journal of Sedimentary Research 85, 1123–37.CrossRefGoogle Scholar
Gibling, M. R. 2006. Width and thickness of fluvial channel bodies and valley fills in the geological record: a literature compilation and classification. Journal of Sedimentary Research 76, 731–70.CrossRefGoogle Scholar
Gran, K. & Paola, C. 2001. Riparian vegetation controls on braided stream dynamics. Water Resources Research 37, 3275–83.CrossRefGoogle Scholar
Hadlari, T., Rainbird, R. H. & Donaldson, J. A. 2006. Alluvial, eolian and lacustrine sedimentology of a Paleoproterozoic half-graben, Baker Lake Basin, Nunavut, Canada. Sedimentary Geology 190, 47–70.CrossRefGoogle Scholar
Hilbert, N. N., Guedes, C. C. F. & Giannini, P. C. F. 2016. Morphologic and sedimentologic patterns of active aeolian dune-fields on the east coast of Maranhão, northeast Brazil. Earth Surface Processes and Landforms 41, 87–97.CrossRefGoogle Scholar
Hjellbakk, A. 1997. Facies and fluvial architecture of a high-energy braided river: the upper Proterozoic Seglodden Member, Varanger Peninsula, northern Norway. Sedimentary Geology 114, 131–61.CrossRefGoogle Scholar
Hooke, J. M. 1986. The significance of mid-channel bars in an active meandering river. Sedimentology 33, 839–50.CrossRefGoogle Scholar
Hooke, J. M. 2007. Complexity, self-organization and variation in behaviour in meandering rivers. Geomorphology 91, 236–58.CrossRefGoogle Scholar
Ielpi, A. & Ghinassi, M. 2014. Planform architecture, stratigraphic signature and morphodynamics of an exhumed Jurassic meander plain (Scalby Formation, Yorkshire, UK). Sedimentology 61, 1923–60.CrossRefGoogle Scholar
Ielpi, A. & Ghinassi, M. 2015. Planview style and palaeodrainage of Torridonian channel belts: Applecross Formation, Stoer Peninsula, Scotland. Sedimentary Geology 325, 1–16.CrossRefGoogle Scholar
Ielpi, A. & Rainbird, R. H. 2015. Architecture and morphodynamics of a 1.6 Ga fluvial sandstone: Ellice Formation of Elu Basin, Arctic Canada. Sedimentology 62, 1950–77.CrossRefGoogle Scholar
Ielpi, A. & Rainbird, R. H. 2016. Highly variable Precambrian fluvial style recorded in the Nelson Head Formation of Brock Inlier (Northwest Territories, Canada). Journal of Sedimentary Research 86, 199–216.CrossRefGoogle Scholar
Jackson, R. G., II. 1976. Depositional model of point bars in the lower Wabash River. Journal of Sedimentary Petrology 46, 579–94.Google Scholar
Jefferson, C. W., Thomas, D. J., Gandhi, S. S., Ramaekers, P., Delaney, G., Brisbin, D., Cutts, C., Portella, P. & Olson, R. A. 2007. Unconformity-associated uranium deposits of the Athabasca Basin, Saskatchewan and Alberta. In EXTECH IV: Geology and Uranium EXploration TECHnology of the Proterozoic Athabasca Basin, Saskatchewan and Alberta (eds Jefferson, C. W. & Delaney, G. D.), pp. 23–67. Geological Survey of Canada, Bulletin 588.Google Scholar
Langford, R. P. 1989. Fluvial-aeolian interactions: part I, modern systems. Sedimentology 36, 1023–35.CrossRefGoogle Scholar
Lazarus, E. D. & Constantine, J. D. 2013. Generic theory for channel sinuosity. Proceedings of the National Academy of Science 110, 8447–52.CrossRefGoogle ScholarPubMed
Levin, N., Tsoar, H., Maia, L. P., Sales, V. C. & Herrmann, H. 2006. Dune whitening and inter-dune freshwater ponds in NE Brazil. Catena 70, 1–15.CrossRefGoogle Scholar
Liu, B. & Coulthard, T. J. 2015. Mapping the interactions between rivers and sand dunes: implications for fluvial and aeolian geomorphology. Geomorphology 231, 246–57.CrossRefGoogle Scholar
Long, D. F. G. 2006. Architecture of pre-vegetation sandy-braided perennial and ephemeral river deposits the Paleoproterozoic Athabasca Group, northern Saskatchewan, Canada as indicators of Precambrian fluvial style. Sedimentary Geology 190, 71–95.CrossRefGoogle Scholar
Long, D. F. G. 2011. Architecture and depositional style of fluvial systems before land plants: a comparison of Precambrian, early Paleozoic and modern river deposits. In From River to Rock Record: The Preservation of Fluvial Sediments and their Subsequent Interpretation (eds Davidson, S., Leleu, S. & North, C. P.), pp. 37–61. SEPM Special Publication 97.Google Scholar
Luna, M. C. de, M., Parteli, E. J. R., Durán, O. & Herrmann, H. J. 2011. Model for the genesis of coastal dune fields with vegetation. Geomorphology 129, 215–24.CrossRefGoogle Scholar
Miranda, J. P., Costa, J. C. L. & Rocha, C. F. D. 2012. Reptiles from Lençóis Maranhenses National Park, Maranhão, northeastern Brazil. ZooKeys 246, 51–68.CrossRefGoogle Scholar
Nicoll, T. J. & Hickin, E. J. 2010. Planform geometry and channel migration of confined meandering rivers on the Canadian prairies. Geomorphology 116, 37–47.CrossRefGoogle Scholar
Prave, A. R. 2002. Life on land in the Proterozoic: evidence from the Torridonian rocks of northwest Scotland. Geology 30, 811–4.2.0.CO;2>CrossRefGoogle Scholar
Pulvertaft, T. C. R. 1985. Aeolian dune and wet interdune sedimentation in the middle Proterozoic Dala Sandstone, Sweden. Sedimentary Geology 44, 93–111.CrossRefGoogle Scholar
Rainbird, R. H. 1992. Anatomy of a large-scale braid-plain quartzarenite from the Neoproterozoic Shaler Group, Victoria Island, Northwest Territories, Canada. Canadian Journal of Earth Sciences 29, 2537–50.CrossRefGoogle Scholar
Rhoads, B. L. & Welford, M. R. 1991. Initiation of river meandering. Progress in Physical Geography 15, 127–56.CrossRefGoogle Scholar
Rust, B. R. 1981. Sedimentation in an arid-zone anastomosing fluvial system: Cooper's Creek, Central Australia. Journal of Sedimentary Petrology 51, 745–55.Google Scholar
Santos, M. G. M., Almeida, R. P., Godinho, L. P. S., Marconato, A. & Mountney, N. P. 2014. Distinct styles of fluvial deposition in a Cambrian rift basin. Sedimentology 61, 881–914.CrossRefGoogle Scholar
Santos, M. G. M. & Owen, G. 2016. Heterolithic meandering-channel deposits from the Neoproterozoic of NW Scotland: implications for palaeogeographic reconstructions of Precambrian sedimentary environments. Precambrian Research 272, 226–43.CrossRefGoogle Scholar
Schumm, S. A. 1981. Evolution and response to the fluvial system, sedimentologic implications. In Recent and Ancient Nonmarine Environments: Models for Exploration (eds Ethridge, F. G. & Flores, R. M.), pp. 19–29. SEPM Special Publication 31.CrossRefGoogle Scholar
Schwartz, D. E. 1978. Hydrology and current orientation analysis of a braided-to-meandering transition: the Red River in Oklahoma and Texas, U.S.A. In Fluvial Sedimentology (ed. Miall, A. D.), pp. 313–42. Canadian Society of Petroleum Geologists, Memoir 5.Google Scholar
Seminara, G. 2006. Meanders. Journal of Fluid Mechanics 554, 271–97.CrossRefGoogle Scholar
Smith, N. D. 1977. Some comments on terminology for bars in shallow rivers. In Fluvial Sedimentology (ed. Miall, A. D.), pp. 85–88. Canadian Society of Petroleum Geologists, Memoir 5.Google Scholar
Smith, C. E. 1998. Modeling high sinuosity meanders in a small flume. Geomorphology 25, 19–30.CrossRefGoogle Scholar
Smith, D. G., Hubbard, S. M., Leckie, D. & Fustic, M. 2009. Counter point bar deposits: lithofacies and reservoir significance in the meandering modern Peace River and ancient McMurray Formation, Alberta, Canada. Sedimentology 56, 1655–69.CrossRefGoogle Scholar
Smith, N. D. & Smith, D. G. 1984. William River: an outstanding example of channel widening and braiding caused by bed-load addiction. Geology 12, 78–82.2.0.CO;2>CrossRefGoogle Scholar
Stølum, H.-H. 1996. River meandering as a self-organization process. Science 271, 1710–3.CrossRefGoogle Scholar
Tal, M. & Paola, C. 2007. Dynamic single-thread channels maintained by the interaction of flow and vegetation. Geology 35, 347–50.CrossRefGoogle Scholar
Thomas, R. G., Williams, B. P. J., Morrissey, L. B., Barclay, W. J. & Allen, K. C. 2006. Enigma variations: the stratigraphy, provenance, palaeoseismicity and depositional history of the Lower Old Red Sandstone Cosheston Group, south Pembrokeshire, Wales. Geological Journal 41, 481–536.CrossRefGoogle Scholar
Tirsgaard, H. & Øxnevad, I. E. I. 1998. Preservation of pre-vegetational mixed fluvio-aeolian deposits in a humid climatic setting: an example from the Middle Proterozoic Eriksfjord Formation, Southwest Greenland. Sedimentary Geology 120, 295–317.CrossRefGoogle Scholar
Todd, S. P. & Went, D. J. 1991. Lateral migration of sand-bed rivers: examples from the Devonian Glashabeg Formation, SW Ireland and the Cambrian Alderney Sandstone Formation, Channel Islands. Sedimentology 38, 997–1020.CrossRefGoogle Scholar
Tubino, M., Repetto, R. & Zolezzi, G. 1999. Free bars in rivers. Journal of Hydraulic Research 37, 759–75.CrossRefGoogle Scholar
Williams, M. 2015. Interactions between fluvial and eolian geomorphic systems and processes: examples from the Sahara and Australia. Catena 134, 4–13.CrossRefGoogle Scholar
Wood, L. J. 2006. Quantitative geomorphology of the Mars Eberswalde delta. Geological Society of America Bulletin 118, 557–66.CrossRefGoogle Scholar
Zimmerman, R. C., Goodlett, J. C. & Comer, G. H. 1967. The influence of vegetation on channel form of small streams. International Association of Hydrological Sciences, Publication 75, 255–75.Google Scholar