Geochemical Evidence for Airborne Dust Additions to Soils in Channel Islands National Park, California

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln USGS Staff -- Published Research US Geological Survey 2008 Geochemical evidence for airborne dust additions to soils in Channel Islands National Park, California Daniel R. Muhs U.S. Geological Survey, [email protected] James R. Budahn U.S. Geological Survey Donald L. Johnson University of Illinois Marith Reheis U.S. Geological Survey Jossh Beann U.S. Geological Survey See next page for additional authors Follow this and additional works at: https://digitalcommons.unl.edu/usgsstaffpub Part of the Earth Sciences Commons Muhs, Daniel R.; Budahn, James R.; Johnson, Donald L.; Reheis, Marith; Beann, Jossh; Skipp, Gary; Fischer, Eric; and Jones, Julia A., "Geochemical evidence for airborne dust additions to soils in Channel Islands National Park, California" (2008). USGS Staff -- Published Research. 160. https://digitalcommons.unl.edu/usgsstaffpub/160 This Article is brought to you for free and open access by the US Geological Survey at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USGS Staff -- Published Research by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Authors Daniel R. Muhs, James R. Budahn, Donald L. Johnson, Marith Reheis, Jossh Beann, Gary Skipp, Eric Fischer, and Julia A. Jones This article is available at DigitalCommons@University of Nebraska - Lincoln: https://digitalcommons.unl.edu/ usgsstaffpub/160 Geochemical evidence for airborne dust additions to soils in Channel Islands National Park, California Daniel R. Muhs James R. Budahn U.S. Geological Survey, M.S. 980, Box 25046, Federal Center, Denver, Colorado 80225, USA Donald L. Johnson Department of Geography, University of Illinois, Urbana, Illinois 61801, USA Marith Reheis Jossh Beann Gary Skipp Eric Fisher U.S. Geological Survey, M.S. 980, Box 25046, Federal Center, Denver, Colorado 80225, USA Julia A. Jones Department of Geosciences, 104 Wilkinson Hall, Oregon State University, Corvallis, Oregon 97331-5506, USA ABSTRACT are from the northwest in coastal California, Reynolds et al., 2001, 2006; Muhs and Bene- easterly winds occur numerous times of the dict, 2006). There is an increasing awareness that dust year when “Santa Ana” conditions prevail, Dust can form the parent material for soils plays important roles in climate change, bio- caused by a high-pressure cell centered over or can infl uence soils that have developed from geochemical cycles, nutrient supply to ecosys- the Great Basin. The eolian silt mantles con- other parent materials (see Birkeland, 1999, tems, and soil formation. In Channel Islands stitute an important medium of plant growth for many examples). Yaalon and Ganor (1973) National Park, California, soils are clay-rich and provide evidence that abundant eolian present a useful conceptual model of the Vertisols or Alfi sols and Mollisols with vertic silt and clay may be delivered to the eastern importance of dust to soils, based on fi eld cri- properties. The soils are overlain by silt-rich Pacifi c Ocean from inland desert sources. teria. They recognize four broad members in a mantles that contrast sharply with the under- continuum of varying eolian infl uence. At one lying clay-rich horizons. Silt mantles contain Keywords: Silt mantles, dust, eolian, soils, ma- extreme, soils develop completely from fi ne- minerals that are rare or absent in the volca- rine terraces, volcanic rocks, California, Chan- grained eolian sediment, such as loess. With a nic rocks that dominate these islands. Immo- nel Islands National Park, Santa Cruz Island, decreasing eolian infl uence, soils have devel- bile trace elements (Sc-Th-La and Ta-Nd-Cr) Santa Barbara Island, Anacapa Island, mineral- oped in part from some other parent material, and rare-earth elements show that the basalt ogy, geochemistry, trace elements, rare earths, but such soils still have a substantial dust input. and andesite on the islands have a composi- Santa Ana winds. In fact, in this member of the continuum, eolian tion intermediate between upper-continental dust inputs are signifi cant enough that not only crust and oceanic crust. In contrast, the silt INTRODUCTION have fi ne-grained eolian particles been added fractions and, to a lesser extent, clay fractions to the matrix of the original parent material, but of the silt mantle have compositions closer Dust plays important roles in many aspects also an eolian mantle is found in the upper part to average upper-continental crust and very of Earth’s physical systems (Mahowald et al., of the solum. Still less eolian infl uence can be similar to Mojave Desert dust. Island shelves, 1999, 2006; Harrison et al., 2001; Kohfeld and seen frequently with soils that have received exposed during the last glacial period, could Harrison, 2001). Because dust can travel inter- abundant fi ne-grained eolian inputs and have have provided a source of eolian sediment for continental distances (Rea, 1994; Prospero et developed substantially from them, but these the silt mantles, but this is not supported by al., 2002; Prospero and Lamb, 2003), it can soils lack a purely eolian mantle in their upper mineralogical data. We hypothesize that a infl uence radiative transfers in the atmosphere parts. Finally, there are some soils that have more likely source for the silt-rich mantles is and affect climate (Tegen, 2003). Iron-rich dust evidence of eolian inputs that can be detected airborne dust from mainland California and can fertilize the ocean’s primary producers, only by detailed mineralogical or geochemi- Baja California, either from the Mojave Des- such as phytoplankton (Jickells et al., 2005) cal studies, because the eolian infl uence is not ert or from the continental shelf during gla- and, consequently, can affect the global carbon apparent in the fi eld. Yaalon and Ganor (1973) cial low stands of sea. Although average winds cycle (Falkowski et al., 1998). Furthermore, refer to such a condition as “eolian contamina- dust may be important for plant communities in tion,” implying that while the eolian input can *[email protected] nutrient-limited ecosystems (Swap et al., 1992; be identifi ed and measured, it is secondary to GSA Bulletin; January/February 2008; v. 120; no. 1/2; p. 106–126; doi: 10.1130/B26218.1; 18 fi gures; Data Repository Item 2007261. 106 For permission to copy, contact [email protected] © 2007 Geological Society of America Dust in Channel Islands soils another parent material with regard to impor- Coudé-Gaussen, 1987), and thicker paleosol rocks, sediments, and soils are very useful tance for pedogenesis. sequences on these islands may have similar ori- for provenance studies. We chose two suites Soil and Quaternary stratigraphic studies over gins (Zöller et al., 2003, 2004). In many parts of relatively immobile elements, Sc-Th-La the past few decades have identifi ed good exam- of the Mojave Desert in California, there are and Ta-Nd-Cr. These elements, when arrayed ples of the extreme end members of the dust- numerous occurrences of silt-rich eolian mantles on ternary plots, show clearly separated com- soil continuum of Yaalon and Ganor (1973). on basaltic volcanic fl ows or alluvial fan depos- positional fi elds for oceanic crust and upper Thick loess deposits of China, Europe, New its of variable lithologies (Wells et al., 1985; continental crust (e.g., Taylor and McLennan, Zealand, South America, and North America McFadden et al., 1986, 1998; Reheis et al., 1995; 1985, p. 29). If the particles in the silt mantles are obvious examples of parent material for Anderson et al., 2002). The Mojave Desert silt are locally derived, they should plot within the soils developed entirely from a fi ne-grained mantles commonly have numerous vesicles and basalt or andesite fi elds of the local bedrock. eolian sediment. At the other extreme, there are are often referred to as “vesicular horizons” or If the mantles are dominantly dust particles also good examples of “eolian contamination” “Av” horizons. Along with clay-rich Australian derived from an external source, the silt par- of soils, from both short-range and long-range loess, or “parna” (Hesse and McTainsh, 2003), ticles will likely have a composition that falls transportation. Basalt-hosted soils of Victoria, the silt mantles of the Canaries and the Mojave on or close to that of upper-continental crust. Australia, contain quartz, which must be derived may be some of the best examples of what has The rare-earth elements (REE), La through from an external source (Jackson et al., 1972). been called “desert loess,” or eolian silt that does Lu, also can be valuable as provenance indica- Long-range eolian transport of exotic particles, not have a glaciogenic origin. tors. The upper-continental crust (UCC) has a such as Asian quartz in basalt-derived soils of Several of the Channel Islands, off the coast distinctive composition with regard to REE Hawaii, is well documented (Rex et al., 1969). of California (Fig. 1), have soils developed on (Taylor et al., 1983; McLennan 1989; Taylor There are fewer examples of the intermedi- volcanic substrates, mainly Miocene andesite and McLennan, 1985, 1995). On chondrite- ate members of the Yaalon and Ganor (1973) and basalt. Muhs (1983) reported silt mantles, normalized REE plots, sediments from the dust-soil continuum. Exceptions to this include interpreted to be of eolian origin, on marine ter- UCC are characterized by enriched light REE, the rapidly accumulating evidence that much races cut into andesite on San Clemente Island. a negative Eu anomaly, and depleted heavy REE of the carbonate and clay in desert soils may A recent reexamination of these features on San (expressed on plots as a “fl at” curve). Loesses be of eolian origin, despite the absence of an Clemente Island confi rms that they are likely from a variety of regions worldwide have a obvious eolian mantle.

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