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Measuring the time and scale-dependency of subaerial rock weathering rates over geologic time scales with ground-based lidar

Amit Mushkin, Amir Sagy, Eran Trabelci, Rivka Amit and Naomi Porat
Measuring the time and scale-dependency of subaerial rock weathering rates over geologic time scales with ground-based lidar
Geology (Boulder) (October 2014) 42 (12): 1063-1066

Abstract

The evolution of roughness as a function of surface age was used to quantify weathering rates on rocky desert surfaces. Surface topography on eight late Quaternary alluvial terraces, which record the weathering of Holocene (5 + or - 1 ka) boulder-strewn deposits into mature (87 + or - 2 ka) desert pavements in the Negev desert of Israel, was measured with ground-based lidar. Roughness on each terrace was characterized with power spectral density (PSD) analysis, and changes in PSD as a function of length scale (lambda approximately 0.04-1.50 m) and surface age were used to estimate diminution/weathering rates of the surface rocks. We found PSD values that systematically increase as a power-law function of lambda (roughness exponent of approximately 2.0) and decrease as an inverse power-law function of surface age. This PSD evolution indicates a fragmentation rock weathering process driven by salt shattering throughout the 87 k.y. period examined. PSD analysis of the lidar data also revealed weathering rates that increase with rock size and decrease as an inverse power-law function of time, from initial values >20 mm/k.y. to <1 mm/k.y. within approximately 60 k.y.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 42
Serial Issue: 12
Title: Measuring the time and scale-dependency of subaerial rock weathering rates over geologic time scales with ground-based lidar
Affiliation: Geological Survey of Israel, Jerusalem, Israel
Pages: 1063-1066
Published: 20141017
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 30
Accession Number: 2014-102338
Categories: Geomorphology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2014366
Illustration Description: illus. incl. 1 table, sketch map
N30°00'00" - N31°00'00", E34°49'60" - E35°10'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201451
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