The Formation of Clay-Enriched Horizons by Lessivage
Abstract
©2018. American Geophysical Union. All Rights Reserved. Soils with argillic horizons
comprise more than 25% of the Earth's surface. Although their origin is still debated,
lessivage is often invoked to explain them, but the long timescales involved hinder
its direct experimental verification. We present a parsimonious model of clay transport,
formulated for long timescales over which lessivage is modeled stochastically, complemented
by detailed field observations. This probabilistic description allows us to predict
the clay profile, the depth of the Bt horizon from the surface, and the mean clay
residence time. The results are tested with field measurements at different locations
in the Calhoun Critical Zone Observatory. Dimensional analysis unveils two dimensionless
parameters governing lessivage dynamics, leading to a classification based on erosion
rates and lessivage characteristics. We identify static and eluviated regimes, in
which erosion or eluviation prevails, and an illuviated regime, in which the balance
between lessivage and erosion brings about the formation of a Bt horizon.
Type
Journal articleSubject
Science & TechnologyPhysical Sciences
Geosciences, Multidisciplinary
Geology
formation of clay-enriched horizons
lessivage model
clay profiles classification
Bt horizon
clay translocation
UNDISTURBED SOIL COLUMNS
COLLOID MOBILIZATION
GENESIS
ILLUVIATION
EVOLUTION
TRANSPORT
MODEL
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https://hdl.handle.net/10161/21231Published Version (Please cite this version)
10.1029/2018GL078778Publication Info
Calabrese, S; Richter, DD; & Porporato, A (2018). The Formation of Clay-Enriched Horizons by Lessivage. Geophysical Research Letters, 45(15). pp. 7588-7595. 10.1029/2018GL078778. Retrieved from https://hdl.handle.net/10161/21231.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Amilcare Porporato
Adjunct Professor in the Department of Civil and Environmental Engineering
Amilcare Porporato earned a Master Degree in Civil Engineering (summa cum laude) in
1992 and his Ph.D. in 1996 from Polytechnic of Turin. He was appointed Assistant Professor
in the Department of Hydraulics of the Polytechnic of Turin, and he moved to Duke
University in 2003, where he is now Full Professor in the Department of Civil and
Environmental Engineering with a secondary appointment with the Nicholas School of
the Environment.
In June 1996, Porporato received the Arturo Parisatti
Daniel D. Richter
Professor in the Division of Earth and Climate Science
Richter’s research and teaching links soils with ecosystems and the wider environment,
most recently Earth scientists’ Critical Zone. He focuses on how humanity is transforming
Earth’s soils from natural to human-natural systems, specifically how land-uses alter
soil processes and properties on time scales of decades, centuries, and millennia.
Richter's book, Understanding Soil Change (Cambridge University Press), co-authored
with his former PhD
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