Colluvial sedimentation in a hyperarid setting (Atacama Desert, northern Chile): Geomorphic controls and stratigraphic facies variability

Sedimentology - Tập 60 Số 5 - Trang 1257-1290 - 2013
Dario Ventra1, Guillermo Chong Dı́az2, Poppe L. de Boer1
1Faculty of Geosciences Utrecht University Budapestlaan 4 3584CD Utrecht The Netherlands
2Departamento de Ciencias Geológicas, Universidad Católica del Norte, Avenida Angamos, 0610 Antofagasta, Chile

Tóm tắt

AbstractResearch on colluvial depositional systems has recently emphasized periglacial and high‐altitude settings, and the relations between Quaternary slope stratigraphy and climate change. This article examines the role of variable slope morphology, surface hydrology and microclimate in controlling colluvial sedimentation along a coastal tract of the hyperarid Atacama Desert in northern Chile. Direct accessibility of active surfaces is accompanied by uninterrupted stratigraphic exposures along the base of slopes, allowing direct comparisons between surface processes and the resulting sedimentary record. Four slope sectors are identified, based on differences in morphology and processes over active surfaces. Colluvial sedimentation is controlled by complex interactions of slope gradients and profiles, exposure to dominant winds, and potential runoff pathways, which vary considerably between different sectors. Major differences are evident between these hyperarid deposits and slope sedimentation in periglacial and temperate settings, including the complete absence of pedogenic activity and clay minerals; the volume of aeolian deposits and their role in controlling processes which redistribute sediment downslope, extending colluvial aprons; and the occurrence of runoff processes only where favoured by particular topographic configurations. Depositional surfaces range from steep talus cones, to debris‐flow‐dominated and aeolian‐dominated colluvial aprons, to an aeolian ramp subject to reworking by mass flows and flash floods. Consequently, facies associations and architectures at outcrop are highly variable and highlight the importance of spatial variations in slope morphology and processes in producing distinct, coeval colluvial stratigraphies within a single environmental context. Discrepancies between active processes and the corresponding stratigraphic signatures are also evident in some sectors; for example, preservation of alluvial and aeolian facies in stratigraphic sections does not always reflect the dominant processes over active slopes. Together with the spatial variability in processes and deposits along these slopes, this suggests that caution is required when extracting palaeoenvironmental information from analyses of colluvial successions.

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Tài liệu tham khảo

10.1016/0012-821X(90)90087-E

Arnott R.W.C., 1989, Bedforms, primary structures and grain fabric in the presence of suspended sediment rain, J. Sed. Petrol., 59, 1062

10.1098/rspa.1954.0186

10.1002/(SICI)1096-9837(199807)23:7<625::AID-ESP874>3.0.CO;2-F

10.1111/j.1365-3091.1997.tb00421.x

Blair T.C., 1987, Sedimentary processes, vertical stratification sequences, and geomorphology of the Roaring River alluvial fan, Rocky Mountain National Park, Colorado, J. Sed. Petrol., 57, 1

Blair T.C., 2002, Int. Assoc. Sedimentol. Spec. Publ., 32, 113

10.1130/0-8137-2370-1.105

Blair T.C., 1994, Alluvial fans and their natural distinction from rivers based on morphology, hydraulic processes, sedimentary processes, and facies assemblages, J. Sed. Res., 64, 450

10.2110/jsr.68.800

10.2110/jsr.69.6

10.1046/j.1365-3091.1998.00200.x

Boric R. Díaz F.andMaksaev V.(1990)Geología y yacimientos metalíferos de la Región de Antofagasta. Bol. Serv. Nacional de Geología y Minería de Chile 40.

10.1016/0031-0182(86)90109-4

10.1002/esp.3290130606

10.1046/j.1365-3091.1999.00263.x

10.1146/annurev.fl.22.010190.000421

10.1017/S0022112086002495

10.1144/GOCH.3

10.1016/j.geomorph.2005.06.008

Clemmensen L.B., 1986, Storm‐generated eolian sand‐shadows and their sedimentary structures, Veyers Strand, Denmark, J. Sed. Petrol., 56, 520

10.1007/978-94-011-0731-0_4

10.1016/0040-1951(92)90414-2

10.1016/S0169-555X(03)00226-5

10.1007/BF01182546

Dijkmans J.W.A., 1991, Modern periglacial and eolian deposits and landforms in the Søndre Strømfjord area, West Greenland and their palaeoenvironmental implications, Medd. Grønl. Geosci., 25, 39

Doe T.W., 1980, Genetic significance of deformed cross bedding – with examples from the Navajo and Weber Sandstones of Utah, J. Sed. Petrol., 50, 793

Dunai T.J., 2005, Preservation of (Early) Miocene landscapes in the Atacama Desert, northern Chile, Geochim. Cosmochim. Acta, 69, A161

Ferraris B.F., 1978, Explanatory Notes Sheet N.30 (1:250,000), Hoja Antofagasta, Carta Geologica de Chile, 48

10.1002/ppp.3430010107

10.1016/S0169-555X(00)00045-3

10.1306/212F782E-2B24-11D7-8648000102C1865D

Gardner J.S., 1980, Thresholds in Geomorphology, 267

Gerson R., 1982, Talus relicts in deserts: a key to major climatic fluctuations, Israel J. Earth Sci., 31, 123

GHCN (Global Historical Climatology Network)(2008)Data from weather station 85442 SCFA Antofagasta (23.43°S‐70.40°W). Available at:http://www.worldclimate.com/cgi-bin/data.pl?ref=S23W070&#x00A0;+&#x00A0;1102&#x00A0;+&#x00A0;85442W(last visited July 2012).

Harms J.C. Southard J.B. Spearing D.R.andWalker R.G.(1975)Depositional Environments as Interpreted from Primary Sedimentary Structures and Stratification Sequences. Short Course Lecture Notes 2 Society of Economic Paleontologists and Mineralogists Tulsa (OK).

10.1144/0016-764902-083

10.1144/gsjgs.152.1.0051

10.1144/GSL.SP.2005.251.01.08

10.1144/0016-764904-071

Hesp P.A., 1981, The formation of shadow dunes, J. Sed. Petrol., 51, 101, 10.1306/212F7C1B-2B24-11D7-8648000102C1865D

10.1002/ppp.3430060211

10.1016/S0169-555X(99)00103-8

Hewitt K., 1972, Mountain Geomorphology, 17

Hilton‐Johnson W., 1982, Binghamton Symposia in Geomorphology Int. Series, 12, 219

10.1177/0959683608101396

10.1002/(SICI)1096-9837(199806)23:6<545::AID-ESP876>3.0.CO;2-E

10.1002/hyp.5926

10.1111/j.1365-3091.1977.tb00128.x

10.1111/j.1365-3121.2008.00817.x

10.1029/97RG00426

Iverson R.M., 2003, Encyclopedia of Sediments and Sedimentary Rocks, 347

10.1029/2009JF001514

10.1016/S0169-555X(00)00035-0

10.1016/S0031-0182(03)00271-2

10.1016/0037-0738(95)00029-8

10.1016/j.cretres.2008.05.016

10.1086/628097

Kocurek G., 1986, Bingham Symp. Geomorph., Int. Ser., 7, 177

Kocurek G., 1981, Distinctions and uses of stratification types in the interpretation of eolian sand, J. Sed. Petrol., 51, 579

10.1016/0169-555X(95)00101-A

Lea P.D., 1990, Pleistocene periglacial eolian deposits in southwestern Alaska: sedimentary facies and depositional processes, J. Sed. Petrol., 60, 582

10.1086/314377

10.1111/j.1365-3121.1992.tb00449.x

10.1002/esp.3290010309

10.1111/j.1365-3091.2006.00829.x

10.1016/0037-0738(93)90090-R

10.1130/0016-7606(1999)111<1424:DFDEOP>2.3.CO;2

Marchant M., 2007, The Geology of Chile, 289, 10.1144/GOCH.11

10.1016/S0169-555X(98)00116-0

Maul G., 2005, Encyclopedia of Coastal Science, 1049

10.1130/0016-7606(1971)82[359:DOLLIE]2.0.CO;2

Middleton G.V., 1970, Geol. Soc. Can. Spec. Pap., 7, 253

Miller A., 1976, Climates of Central and South America, 113

Mortimer C., 1972, Landform evolution in the coastal region of Tarapaca Province, Rev. Géomorphol. Dynam., 21, 162

10.1002/9781444304299.ch9

Muñoz J.F., 2007, The Geology of Chile, 215, 10.1144/GOCH.8

Nelson A.R., 1992, Lithofacies analysis of colluvial sediments – an aid in interpreting the recent history of Quaternary normal faults in the Basin and Range province, western United States, J. Sed. Petrol., 62, 607

10.1002/9781444303858.ch3

10.1046/j.1365-3091.1999.00210.x

Nemec W., 1982, Volcaniclastic alluvial aprons in the Tertiary Sofia District (Bulgaria), Ann. Soc. Geol. Pol., 52, 239

Neuendorf K.K.E., 2005, Glossary of Geology

10.1144/GSL.SP.1987.029.01.02

10.1016/j.geomorph.2005.07.010

10.1130/0091-7613(2000)028<0027:AHDMLI>2.0.CO;2

10.1130/0016-7606(2001)113<0305:CTMQAN>2.0.CO;2

10.1111/j.1365-3091.1987.tb00793.x

10.1086/627343

Ritter D.F., 1995, Process Geomorphology

10.1086/628568

10.1016/j.sedgeo.2010.05.002

10.1007/s10347-008-0175-z

10.1016/j.geomorph.2006.08.012

10.1017/S002211208800103X

10.1016/0191-8141(90)90008-M

10.2475/ajs.263.2.110

Selby M.J., 1993, Hillslope Material and Processes, Ch. 15, 320

10.1080/00288306.1973.10421580

10.2110/pec.91.45.0059

10.1111/j.1365-3091.1993.tb01359.x

Sohn Y.K., 1997, Characteristics and depositional processes of large‐scale gravelly Gilbert‐type foresets in the Miocene Doumsan fan delta, Phang Basin, SE Korea, J. Sed. Res., 67, 130

10.1002/esp.3290010106

Statham I., 1986, Hillslope Processes, 245

Steidtmann J.R., 1973, Mechanism for large‐scale deformation in eolian dunes, AAPG Bull., 57, 806

Suwa H., 1988, Focusing mechanism of large boulders to a debris‐flow front, Trans. Jpn Geomorphol. Union, 9, 151

Tanner L.H., 1991, Basalt breccias and conglomerates of the Lower Jurassic McCoy Brook Formation, Fundy Basin, Nova Scotia: differentiation of talus and debris‐flow deposits, J. Sed. Petrol., 61, 15

10.1002/jqs.752

10.1006/qres.1997.1923

Tomczak M., 1994, Regional Oceanography: An Introduction

Turner A.K., 1996, Landslides – Investigation and Mitigation, 525

10.1046/j.1365-3091.2002.00497.x

10.1002/ppp.3430060210

10.1191/0309133302pp352ra

Vargas G., 2000, Aluviones históricos en Antofagasta y su relación con eventos El Niño/Oscilación del Sur, Rev. Geol. Chile, 27, 157

Wilson P., 2009, Geol. Soc. London, Spec. Publ., 320, 133, 10.1144/SP320.9

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Sedimentology

Tập 60 Số 5

1257-1290

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