colluvium versus alluvium - usda

Colluvium Versus Alluvium:Preliminary Survey Results

Bradley Miller Jérôme Juilleret

http://www.list.lu/

http://www.list.lu/

Survey Goals

• Identify if variation exists in definitions used by practicing scientists

• If variation exists, ‘map’ the different definitions to assist translation and understanding

• Look for common ground or potential paths forward

The Purpose of Classification

• Improve understanding• Improve communication

Demographics

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

High School B.S. M.S. Ph.D. Ph.D. +

Level of Education

14.4%

19.2%

63.5%

3.0%

Work Sector

Private Government Academia None of the above

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

High School B.S. M.S. Ph.D. Ph.D. +

Level of Education

12.6%

16.2%

66.7%

4.5%

Work Sector

Private Government Academia None of the above

USA (111 respondents) Europe (110 respondents)

Primary Research Discipline

16%

48%8%

19%

9%

USA

Geology Geomorphology Physical Geography Soil Science Other

12%

31%

11%

36%

10%

Europe

Geology Geomorphology Physical Geography Soil Science Other

Field CriteriaDo the definitions for colluvium and alluvium need to be based exclusively on field identifiable criteria?

USA Europe

49.8% 50.2%

Yes No

55.9%44.1%

Yes No

Colluvium Transport Processes: USA

83.0%

8.1%8.9%

Rapid Mass Movement

Yes No Maybe

85.6%

6.3%8.1%

Slow Mass Movement

Yes No Maybe

49.8%26.0%

24.2%

Sheet or Overland Flow

Yes No Maybe

22.6%

45.9%

31.5%

Rills and Ephemeral Gullies

Yes No Maybe

15.5%

63.5%

21.0%

Permanent Gulliesand Ravines

Yes No Maybe

35.1%

37.3%

27.7%

Debris or Mud Flow

Yes No Maybe

5.6%

85.2%

9.3%

Floodplains, Terraces, and Wadi

Yes No Maybe

3.7%

92.3%

4.1%

Permanent Running Water

Yes No Maybe

Colluvium Transport Processes: Europe

72.1%14.4%

13.5%

Rapid Mass Movement

Yes No Maybe

79.3%

9.0%

11.7%

Slow Mass Movement

Yes No Maybe

58.6%21.6%

19.8%

Sheet orOverland Flow

Yes No Maybe

31.5%

36.0%

32.4%


Yes No Maybe

20.7%

52.3%

27.0%


Yes No Maybe

38.7%

31.5%

29.7%

Debris or Mud Flow

Yes No Maybe

7.3%

80.0%

12.7%


Yes No Maybe

3.6%

91.9%

4.5%


Yes No Maybe

Alluvium Transport Processes: USA

5.6%

91.1%

3.3%

Rapid Mass Movement

Yes No Maybe

5.9%

86.7%

7.4%

Slow Mass Movement

Yes No Maybe

37.9%

37.5%

24.5%


Yes No Maybe

51.7%21.6%

26.8%


Yes No Maybe

70.7%14.4%

14.8%


Yes No Maybe

48.9%24.1%

27.0%

Debris or Mud Flow

Yes No Maybe

92.9%

3.3% 3.7%


Yes No Maybe

92.2%

6.3% 1.5%


Yes No Maybe

Alluvium Transport Processes: Europe

1.8%

93.7%

4.5%

Rapid Mass Movement

Yes No Maybe

2.7%

91.0%

6.3%

Slow Mass Movement

Yes No Maybe

27.0%

52.3%

20.7%


Yes No Maybe

41.4%

36.0%

22.5%


Yes No Maybe

61.3%24.3%

14.4%


Yes No Maybe

43.2%

28.8%

27.9%

Debris or Mud Flow

Yes No Maybe

92.7%

3.6% 3.6%


Yes No Maybe

91.9%

7.2% 0.9%


Yes No Maybe

Differentiating Deposit MaterialsPlease rank the importance of the following diagnostic criteria that you would use to differentiate these two deposits/parent materials.

• Distance Traveled (COLLUVIUM = short distance, ALLUVIUM = long distance)

• Connection to Stream (COLLUVIUM = Strahler Order 1, ALLUVIUM = Strahler Order 2 or greater)

• Landscape Position (COLLUVIUM = hillslopes, ALLUVIUM = river valleys)

• Degree of Sorting (COLLUVIUM = poorly sorted, ALLUVIUM = well sorted)

• Shaping of Particles (COLLUVIUM = angular, ALLUVIUM = rounded)

• Stratification (i.e. layering)(COLLUVIUM = rare and chaotic, ALLUVIUM = common and clear)

• Lithology (COLLUVIUM = matches upslope material, ALLUVIUM = differs from upslope material)

Criteria for Differentiating: USAPlease rank the importance of the following diagnostic criteria that you would use to differentiate these two deposits/parent materials.

0

50

100

150

1 2 3 4 5 6 7

Distance Traveled

0

50

100

150

1 2 3 4 5 6 7

Connection to Stream

0

50

100

150

1 2 3 4 5 6 7

Landscape Position

0

50

100

150

1 2 3 4 5 6 7

Degree of Sorting

0

50

100

150

1 2 3 4 5 6 7

Shaping of Particles

0

50

100

150

1 2 3 4 5 6 7

Stratification

0

50

100

150

1 2 3 4 5 6 7

Lithology

47% 60% 93%

79% 69% 69% 53%

Criteria for Differentiating: EuropePlease rank the importance of the following diagnostic criteria that you would use to differentiate these two deposits/parent materials.

0

20

40

60

80

1 2 3 4 5 6 7

Distance Traveled

0

20

40

60

80

1 2 3 4 5 6 7

Connection to Stream

0

20

40

60

80

1 2 3 4 5 6 7

Landscape Position

0

20

40

60

80

1 2 3 4 5 6 7

Degree of Sorting

0

20

40

60

80

1 2 3 4 5 6 7

Shaping of Particles

0

20

40

60

80

1 2 3 4 5 6 7

Stratification

0

20

40

60

80

1 2 3 4 5 6 7

Lithology

56% 54% 92%

76% 72% 60% 64%

Which material is MOST represented in this picture?

78.4%

1.8%

2.7%17.1%

Image: Randy Schaetzl

USA

Europe

84.0%

0.7%2.6%

12.6%


Image: Jérôme Juilleret

63.1%9.9%

7.2%

19.8%

USA

Europe

64.3%10.4%

6.7%

18.6%


Image: Randy Schaetzl

0.9%

57.7%

11.7%

29.7%

USA

Europe1.5%

68.0%

8.2%

22.3%



7.2%

63.1%

5.4%

24.3%

USA

Europe

11.6%

53.6%3.7%

31.1%


Image: Lee Burras

26.9%

31.5%

17.6%

24.1%

USA

Europe

35.5%

21.9%

12.5%

30.2%


Image: Lee Burras

50.0%

15.5%

10.9%

23.6%

USA

Europe

62.5%11.2%

7.8%

18.6%

Feedback from Survey

“I like to see the final results of the survey, it is always a "hot" topic among geomorphologists. I had fun take part in the survey.”

“bravo pour l'enquête”

“Good idea this survey, and very good diffusion in a large community. Could help with other terms.”

“a majority cannot claim a mandate”

“Doing this is a great idea!”

Feedback from SurveyAdded complications/opportunities:• Russians have:

• Alluvium - Sediments deposited by permanent water flows in river valleys

• Deluvium - Deposits resulting from the accumulation of sediments eroded from the slopes by rain and snowmelt

• Proluvium - Deposits of sediments by temporary water streams

• Colluvium - Weathering products shifted down the slope under the influence of gravity

Literature Contains a Variety of Definitions• Colluvium is poorly sorted debris that has accumulated at the base of

slopes, in depressions, or along small streams through gravity, soil creep, and local wash. It consists largely of material that has rolled, slid or fallen down the slope under the influence of gravity. Accumulations of rock fragments are called talus. The rock fragments in colluvium are usually angular, in contrast to the rounded, water-worn cobbles and stones in alluvium and glacial outwash. (USA Soil Survey Staff, 1993)

• Alluvium - Sediments deposited by running water of streams and rivers. It may occur on terraces well above present streams, on the present flood plains or deltas, or as a fan at the base of a slope. (Soil Science Society of America, 2008)

Your Feedback?

Next Steps

• A lot of sorting and analysis to absorb the information

• Round 2• Identify potential strategies for

addressing/consolidating different perspectives and needs

• Share results with survey participants• Use a follow-up survey to gauge community

interest in any of the unifying strategies

Literature Contains a Variety of Definitions• Colluvium

• Unconsolidated material at the bottom of a cliff or slope, generally moved by gravity alone. It lacks stratification and is usually unsorted: its composition depends upon its rock source, and its fragments range greatly in size. Such deposits include debris and talus. (Lapidus, 1990)

• Detritus, transported by various processes, that is still adjacent to or on its source hillslope. (Pederson, 2000)

• Sediments deposited due to anthropogenic induced soil erosion, caused by settling, clearing, mining, grazing, and/or farming. (Leopold, 2003)

• (from Latin: co-, with, and alluvium). Footslope deposit. Relatively thin and made of elements which have undergone low transportation compared to alluvium. (Foucault et al, 2014)

Literature Contains a Variety of Definitions• Alluvium

• Alluvium or Alluvion (from Latin, “an inundation”) is a term which in the English language, has no very definite meaning. Some authors use it to designate all rocks which have been formed by causes now acting on the surface of the earth, including those of volcanic origin; while others, adhering to the literal meaning of the original term, confine its application to deposits, whatever be their character, that have resulted from inundation… The term has been badly selected, but is used in its proper application to designate all those deposits recently formed, or now forming, by the agency of water, whether from an interrupted and constant stream, or from casual inundation. (Cuthbert, 1842)

Literature Contains a Variety of Definitions• Alluvium

• The general term for detrital made by rivers or streams or found on alluvial fans, flood plains, etc. Alluvium consists of gravel, sand, silt, and clay and often contains organic matter that makes it a fertile soil. It does not include the subaqueous sediments of lakes and seas. (Lapidus, 1990)

• Materials deposited on the land surface from transport by flowing water confined to a channel or valley floor (Eggleton, 2001)

• Alluvium deposited by unconcentrated surface runoff or sheet erosion, usually at the base of a slope (Neuendorf, 2005)

• (from Latin: alluvio, overflow). Sediments of rivers and lakes composed, according to the regions crossed and the strength of the current, of pebbles, gravels, sand, silt and clay and usually found in lenticular (channel) deposits. (Foucault et al, 2014)

Which material is MOST represented within the blue outline?


0.9%

80.2%

4.5%

14.4%

USA

Europe1.5%

85.2%

2.6%10.7%



71.8%

5.5%

8.2%

14.5%

USA

Europe

81.8%

4.1%4.8%9.3%



35.5%

19.1%8.2%

37.3%

USA

Europe

46.5%

14.9%4.8%

33.8%



80.9%

2.7%2.7%13.6%

USA

Europe

88.5%

1.1%3.3%

7.1%



2.7%

45.9%

22.5%

28.8%

USA

Europe

3.3%

50.7%18.9%

27.0%



12.8%

25.7%

19.3%

42.2%

USA

Europe

15.3%

28.7%

10.1%

45.9%


Image: Lee Burras

4.6%

25.9%

10.2%

59.3%

USA

Europe

2.2%

32.2%

13.1%

52.4%


Image: Lee Burras

24.3%

16.2%

10.8%

48.6%

USA

Europe

25.6%

10.0%

12.2%

52.2%


Image: Lee Burras

22.5%

4.5%

9.0%64.0%

USA

Europe

29.3%

3.0%9.6%

58.1%


Image: Lee Burras

2.7%

39.1%

10.0%

48.2%

USA

Europe

1.9%

46.1%12.0%

40.1%

Feedback from SurveyAdded complications/opportunities:• Glacis – hillslope sediments transported by gravity-

driven processes (France, Spain, Romania)• Diluvium (not deluvium) –slopewash sediments,

including gullies (Poland)• Eluvium• Many (but not all) Germans have a narrow

definition of Kolluvium as derived only from anthropogenic soil erosion

• “Alluvial fans are not made from alluvium, they are made from colluvium.”

colluvium versus alluvium - usda

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