Quantifying hillslope erosion rates and processes for a coastal California landscape over varying timescales

Colin R. O'Farrell, Arjun Heimsath, James M. Kaste

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

The Earth's surface erodes by processes that occur over different spatial and temporal scales. Both continuous, low-magnitude processes as well as infrequent, high-magnitude events drive erosion of hilly soil-mantled landscapes. To determine the potential variability of erosion rates we applied three independent, field-based methods to a well-studied catchment in the Marin Headlands of northern California. We present short-term, basin-wide erosion rates determined by measuring pond sediment volume (40 years) and measured activities of the fallout nuclides 137Cs and 210Pb (40-50 years) for comparison with long-term (>10 ka) rates previously determined from in situ-produced cosmogenic 10Be and 26Al analyses. In addition to determining basin-averaged rates, 137Cs and 210Pb enable us to calculate point-specific erosion rates and use these rates to infer dominant erosion processes across the landscape. When examined in the context of established geomorphic transport laws, the correlations between point rates of soil loss from 137Cs and 210Pb inventories and landscape morphometry (i.e. topographic curvature and upslope drainage area) demonstrate that slope-driven processes dominate on convex areas while overland flow processes dominate in concave hollows and channels. We show a good agreement in erosion rates determined by three independent methods: equivalent denudation rates of 143 ± 41 m Ma-1 from pond sediment volume, 136 ± 36 m Ma-1 from the combination of 137Cs and 210Pb, and 102 ± 25 m Ma-1 from 10Be and 26Al. Such agreement suggests that erosion of this landscape is not dominated by extreme events; rather, the rates and processes observed today are indicative of those operating for at least the past 10 000 years.

Original languageEnglish (US)
Pages (from-to)544-560
Number of pages17
JournalEarth Surface Processes and Landforms
Volume32
Issue number4
DOIs
StatePublished - Apr 15 2007
Externally publishedYes

Fingerprint

erosion rate
hillslope
erosion
timescale
pond
morphometry
overland flow
extreme event
denudation
fallout
event
basin
sediment
curvature
rate
soil
catchment
drainage
Law
present

Keywords

  • Cs
  • Pb
  • Cosmogenic nuclides
  • Geomorphology
  • Landscape evolution

ASJC Scopus subject areas

  • Earth and Planetary Sciences (miscellaneous)
  • Earth-Surface Processes
  • Geography, Planning and Development

Cite this

Quantifying hillslope erosion rates and processes for a coastal California landscape over varying timescales. / O'Farrell, Colin R.; Heimsath, Arjun; Kaste, James M.

In: Earth Surface Processes and Landforms, Vol. 32, No. 4, 15.04.2007, p. 544-560.

Research output: Contribution to journalArticle

@article{41523f3238df426eb585d949952bdea7,
title = "Quantifying hillslope erosion rates and processes for a coastal California landscape over varying timescales",
abstract = "The Earth's surface erodes by processes that occur over different spatial and temporal scales. Both continuous, low-magnitude processes as well as infrequent, high-magnitude events drive erosion of hilly soil-mantled landscapes. To determine the potential variability of erosion rates we applied three independent, field-based methods to a well-studied catchment in the Marin Headlands of northern California. We present short-term, basin-wide erosion rates determined by measuring pond sediment volume (40 years) and measured activities of the fallout nuclides 137Cs and 210Pb (40-50 years) for comparison with long-term (>10 ka) rates previously determined from in situ-produced cosmogenic 10Be and 26Al analyses. In addition to determining basin-averaged rates, 137Cs and 210Pb enable us to calculate point-specific erosion rates and use these rates to infer dominant erosion processes across the landscape. When examined in the context of established geomorphic transport laws, the correlations between point rates of soil loss from 137Cs and 210Pb inventories and landscape morphometry (i.e. topographic curvature and upslope drainage area) demonstrate that slope-driven processes dominate on convex areas while overland flow processes dominate in concave hollows and channels. We show a good agreement in erosion rates determined by three independent methods: equivalent denudation rates of 143 ± 41 m Ma-1 from pond sediment volume, 136 ± 36 m Ma-1 from the combination of 137Cs and 210Pb, and 102 ± 25 m Ma-1 from 10Be and 26Al. Such agreement suggests that erosion of this landscape is not dominated by extreme events; rather, the rates and processes observed today are indicative of those operating for at least the past 10 000 years.",
keywords = "Cs, Pb, Cosmogenic nuclides, Geomorphology, Landscape evolution",
author = "O'Farrell, {Colin R.} and Arjun Heimsath and Kaste, {James M.}",
year = "2007",
month = "4",
day = "15",
doi = "10.1002/esp.1407",
language = "English (US)",
volume = "32",
pages = "544--560",
journal = "Earth Surface Processes and Landforms",
issn = "0197-9337",
publisher = "John Wiley and Sons Ltd",
number = "4",

}

TY - JOUR

T1 - Quantifying hillslope erosion rates and processes for a coastal California landscape over varying timescales

AU - O'Farrell, Colin R.

AU - Heimsath, Arjun

AU - Kaste, James M.

PY - 2007/4/15

Y1 - 2007/4/15

N2 - The Earth's surface erodes by processes that occur over different spatial and temporal scales. Both continuous, low-magnitude processes as well as infrequent, high-magnitude events drive erosion of hilly soil-mantled landscapes. To determine the potential variability of erosion rates we applied three independent, field-based methods to a well-studied catchment in the Marin Headlands of northern California. We present short-term, basin-wide erosion rates determined by measuring pond sediment volume (40 years) and measured activities of the fallout nuclides 137Cs and 210Pb (40-50 years) for comparison with long-term (>10 ka) rates previously determined from in situ-produced cosmogenic 10Be and 26Al analyses. In addition to determining basin-averaged rates, 137Cs and 210Pb enable us to calculate point-specific erosion rates and use these rates to infer dominant erosion processes across the landscape. When examined in the context of established geomorphic transport laws, the correlations between point rates of soil loss from 137Cs and 210Pb inventories and landscape morphometry (i.e. topographic curvature and upslope drainage area) demonstrate that slope-driven processes dominate on convex areas while overland flow processes dominate in concave hollows and channels. We show a good agreement in erosion rates determined by three independent methods: equivalent denudation rates of 143 ± 41 m Ma-1 from pond sediment volume, 136 ± 36 m Ma-1 from the combination of 137Cs and 210Pb, and 102 ± 25 m Ma-1 from 10Be and 26Al. Such agreement suggests that erosion of this landscape is not dominated by extreme events; rather, the rates and processes observed today are indicative of those operating for at least the past 10 000 years.

AB - The Earth's surface erodes by processes that occur over different spatial and temporal scales. Both continuous, low-magnitude processes as well as infrequent, high-magnitude events drive erosion of hilly soil-mantled landscapes. To determine the potential variability of erosion rates we applied three independent, field-based methods to a well-studied catchment in the Marin Headlands of northern California. We present short-term, basin-wide erosion rates determined by measuring pond sediment volume (40 years) and measured activities of the fallout nuclides 137Cs and 210Pb (40-50 years) for comparison with long-term (>10 ka) rates previously determined from in situ-produced cosmogenic 10Be and 26Al analyses. In addition to determining basin-averaged rates, 137Cs and 210Pb enable us to calculate point-specific erosion rates and use these rates to infer dominant erosion processes across the landscape. When examined in the context of established geomorphic transport laws, the correlations between point rates of soil loss from 137Cs and 210Pb inventories and landscape morphometry (i.e. topographic curvature and upslope drainage area) demonstrate that slope-driven processes dominate on convex areas while overland flow processes dominate in concave hollows and channels. We show a good agreement in erosion rates determined by three independent methods: equivalent denudation rates of 143 ± 41 m Ma-1 from pond sediment volume, 136 ± 36 m Ma-1 from the combination of 137Cs and 210Pb, and 102 ± 25 m Ma-1 from 10Be and 26Al. Such agreement suggests that erosion of this landscape is not dominated by extreme events; rather, the rates and processes observed today are indicative of those operating for at least the past 10 000 years.

KW - Cs

KW - Pb

KW - Cosmogenic nuclides

KW - Geomorphology

KW - Landscape evolution

UR - http://www.scopus.com/inward/record.url?scp=34247200027&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=34247200027&partnerID=8YFLogxK

U2 - 10.1002/esp.1407

DO - 10.1002/esp.1407

M3 - Article

AN - SCOPUS:34247200027

VL - 32

SP - 544

EP - 560

JO - Earth Surface Processes and Landforms

JF - Earth Surface Processes and Landforms

SN - 0197-9337

IS - 4

ER -