Stratigraphic architecture of alluvial terraces in the Yunganza river
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Abstract
The study of fluvial sedimentation patterns (FSP) allow us to analyze tectonic and climatic behavior in a specific region, and, understand how rivers modify the relief. FSP can be studied from the analysis of the stratigraphic record of their deposits. In the northern Andes, FSP interact with erosion rates and detritus available for sedimentation rates. In the south of the sub-Andean zone, the Yunganza river basin corresponds to a confined fluvial basin and feeder of the Santiago river, and offers the opportunity to study this region FSP. The aim of this research is to present the stratigraphic record analysis of: ancient alluvial terraces (TA-1 and TA-2) and alluvial deposits (DA) in the Yunganza river basin, in the vicinity of El Rosario in order to define PSF. Our research is supported by documentation of the lithological record, sedimentary structures, stratigraphic architecture, thickness and paleo-currents measurement. Seven facies are described: LT-1 and LT-2 describe conglomerates associated with distal debris flows, whilst, LT-3 describes conglomerates and breccias associated with proximal debris flows. LT-4, and LT-5, and LT-6 describe sandstones genetically linked to bars and fluvial channel macro-forms, last, LT-7 describes siltstones associated with flood plains. Paleocurrent data indicate that: TA-1 presents flow direction to NE-E, whereas, TA-2 indicates a sediment transport direction to N. The TA-1 modal composition indicates a detrital provenance of a sedimentary block rich in quarts, while the TA-2 modal composition indicates a recycling period of TA-1. The thickness measurement in TA-1 and TA-2 indicates an intensely erosive period in TA-1. Finally, fluvial sedimentation patterns in the Yunganza river are genetically linked to periods of exhumation on the west side of the river.
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Aspden, J. A. and Litherland, M. (1992) The geology and Mesozoic collisional history of the Cordillera Real, Ecuador. Tectonophysics, 205(1-3), 187-204. doi:10.1016/0040-1951(92)90426-7
Baby, P., Rivadeneira, M., Barragán, R. and Christophoul, F. (2013) Thick-skinned tectonics in the Oriente foreland basin of Ecuador. Geological Society, London, Special Publications, 377(1), 59-76. doi: 10.1144/SP377.1
Benito, G., Gutiérrez, F., Pérez-González, A. and Machado, M. J. (2000) Geomorphological and sedimentological features in Quaternary fluvial systems affected by solution- induced subsidence (Ebro Basin, ne-Spain). Geomorphology, 33(3-4), 209-224. doi:10.1016/S0169-555X(99)00124-5
Brierley, G. J., Liu, K. and Crook, K. A. (1993) Sedimentology of coarse-grained alluvial fans in the Markham Valley, Papua New Guinea. Sedimentary Geology, 86(3-4), 297- 324. Doi:10.1016/0037-0738(93)90027-3
Bull, W.B. (1977) The alluvial fan environments. Prog. Phys. Geogr., 1, 222e270
Delcaillau, B., Laville, E., Amhrar, M., Namous, M., Dugué, O. and Pedoja, K. (2010) Quaternary evolution of the Marrakech High Atlas and morphotectonic evidence of activity along the Tizi N’Test Fault, Morocco. Geomorphology, 118(3-4), 262-279. Doi:10.1016/j.geomorph.2010.01.006
Fontán, A., Alcántara-Carrió, J., Poveda, J. M., & Peña, M. A. (2007) Aplicación de técnicas de GPS diferencial, fotogrametría y geofísica a la cuantificación de procesos erosivos y balances sedimentarios en playas y dunas costeras. Teledetección-Herramienta para la gestión sostenible. Proc XII Congr Asociación Española de Teledetección, 19-21. ISBN: 975-987-543-127-0
Fontana, A., Mozzi, P. and Marchetti, M. (2014) Alluvial fans and megafans along the southern side of the Alps. Sedimentary Geology, 301, 150-171. Doi: 10.1016/j.sedgeo.2013.09.003
IIGE (2019) Memoria Técnica de la HG-Mendez, esc.1:100.000. Informe no publicado.
James, N.P. and Dalrymple R., W. (2010) Facies Models 4, GEotext 6. Geological Association of Canada.
Jolley, E. J., Turner, P., Williams, G. D., Hartley, A. J. and Flint, S. (1990) Sedimentological response of an alluvial system to Neogene thrust tectonics, Atacama Desert, northern Chile. Journal of the Geological Society, 147(5), 769-784. Doi: 10.1144/gsjgs.147.5.0769
Latrubesse, E. M. (2015) Large rivers, megafans and other Quaternary avulsive fluvial systems: A potential «who’s who» in the geological record. Earth-Science Reviews, 146, 1-30.
Lewin, J., Macklin, M. G. and Johnstone, E. (2005) Interpreting alluvial archives: sedimentological factors in the British Holocene fluvial record. Quaternary Science Reviews, 24(16-17), 1873-1889. Doi:10.1016/j.quascirev.2005.01.009
Litherland, M. (1994) The metamorphic belts of Ecuador. British Geological Survey, Overseas Memoir, 11.
Miall, A. D. (1988) Facies architecture in clastic sedimentary basins. In New perspectives in basin analysis, 67-81. Springer, New York, NY. Doi:10.1007/978-1-4612-3788-4_4
Miall, A. D. (2010) Alluvial deposits, Facies Models, 4. Geological Association of Canada, 105-137, St. John’s, Newfoundland.
Platt, N. H. and Keller, B. (1992) Distal alluvial deposits in a foreland basin setting-the Lower Freshwater Miocene, Switzerland: sedimentology, architecture and palaeosols. Sedimentology, 39(4), 545-565. Doi:10.1111/j.1365-3091.1992.tb02136.x
Pratt, W. T., Duque, P. and Ponce, M. (2005) An autochthonous geological model for the eastern Andes of Ecuador. Tectonophysics, 399(1-4), 251-278. Doi:10.1016/j.tecto.2004.12.025
Reitz, M. D. and Jerolmack, D. J. (2012) Experimental alluvial fan evolution: Channel dynamics, slope controls, and shoreline growth. Journal of Geophysical Research: Earth Surface, 117(F2). Doi:10.1029/2011JF002261
Riel, N., Guillot, S., Jaillard, E., Martelat, J. E., Paquette, J. L., Schwartz, S., Goncalves P., Ducaux, N., Thebaud N., Lanari P., Janots E. and Yuquilema J. (2013) Metamorphic and geochronogical study of the Triassic El Oro metamorphic complex, Ecuador: Implications for high-temperature metamorphism in a forearc zone. Lithos, 156, 41-68. Doi:10.1016/j.lithos.2012.10.005
Sage, F., Collot, J. Y. and Ranero, C. R. (2006) Interplate patchiness and subduction-erosion mechanisms: Evidence from depth-migrated seismic images at the central Ecuador convergent margin. Geology, 34(12), 997-1000. Doi:10.1130/G22790A.1
Sass, O. and Krautblatter, M. (2007) Debris flow-dominated and rockfall-dominated talus slopes: Genetic models derived from gpr measurements. Geomorphology, 86(1-2), 176-192. Doi:10.1016/j.geomorph.2006.08.012
Tedesco, A., Ciccioli, P., Suriano, J. and Limarino, C. O. (2010) Changes in the architecture of fluvial deposits in the Paganzo Basin (Upper Paleozoic of San Juan province): an example of sea level and climatic controls on the development of coastal fluvial environments. Geologica acta, 8(4), 463-482. Doi: 10.1344/105.000001583
Tucker, M. E. (Ed.) (2009) Sedimentary petrology: an introduction to the origin of sedimentary rocks. John Wiley & Sons.
Ventra, D. and Clarke, L. E. (2018) Geology and geomorphology of alluvial and fluvial fans: current progress and research perspectives. Geological Society, London, Special Publications, 440(1), 1-21. Doi:10.1144/SP440.16
Walker, R. G. (1990) Facies modeling and sequence stratigraphy. Journal of Sedimentary Research, 60(5), 777-786.
Weissmann, G. S., Hartley, A. J., Nichols, G. J., Scuderi, L. A., Olson, M., Buehler, H. and Banteah, R. (2010) Fluvial form in modern continental sedimentary basins: distributive fluvial systems. Geology, 38(1), 39-42. Doi: 10.1130/G30242.1