Glacial-interglacial climate changes recorded by debris flow fan deposits, Owens Valley, California
File(s)
Accepted version
Author(s)
D'Arcy, Mitch
Roda-Boluda, Duna C
Whittaker, Alexander C
Type
Journal Article
Abstract
It is hotly debated whether and how climate changes are recorded by terrestrial stratigraphy. Basin sediments produced by catchment-alluvial fan systems may record past climate over a variety of timescales, and could offer unique information about how climate controls sedimentation. Unfortunately, there are fundamental uncertainties about how climatic variables such as rainfall and temperature translate into sedimentological signals. Here, we examine 35 debris flow fan surfaces in Owens Valley, California, that record deposition throughout the past 125,000 years, during which climate has varied significantly. We show that the last full glacial-interglacial cycle is recorded with high fidelity by the grain size distributions of the debris flow deposits. These flows transported finer sediment during the cooler glacial climate, and became systematically coarser-grained as the climate warmed and dried. We explore the physical mechanisms that might explain this signal, and rule out changes in sediment supply through time. Instead, we propose that grain size records past changes in storm intensity, which is responsible for debris flow initiation in this area and is decoupled from average rainfall rates. This is supported by an exponential Clausius-Clapeyron-style scaling between grain size and temperature, and also reconciles with climate dynamics and the initiation of debris flows. The fact that these alluvial fans exhibit a strong, sustained sensitivity to orbital climate changes sheds new light on how eroding landscapes and their sedimentary products respond to climatic forcing. Finally, our findings highlight the importance of threshold-controlled events, such as storms and debris flows, in driving erosion and sedimentation at the Earth's surface in response to climate change.
Date Issued
2017-08-01
Date Acceptance
2017-07-10
Citation
Quaternary Science Reviews, 2017, 169, pp.288-311
ISSN
0277-3791
Publisher
Elsevier
Start Page
288
End Page
311
Journal / Book Title
Quaternary Science Reviews
Volume
169
Copyright Statement
© 2017, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Subjects
Science & Technology
Physical Sciences
Geography, Physical
Geosciences, Multidisciplinary
Physical Geography
Geology
HOURLY PRECIPITATION EXTREMES
SOUTHWESTERN NORTH-AMERICA
FISH SPRINGS FAULT
FREE-SURFACE FLOWS
SIERRA-NEVADA
ALLUVIAL FANS
LANDSCAPE RESPONSE
WHITE MOUNTAINS
GRAIN-SIZE
SOUTHERN CALIFORNIA
Publication Status
Published