Holocene loess deposition and soil formation as competing processes, Matanuska Valley, Southern Alaska

Muhs, Daniel R.; McGeehin, John P.; Beann, Jossh; Fisher, Erich C.

doi:10.1016/j.yqres.2004.02.003

Cited by 86 publications

(66 citation statements)

References 30 publications

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“…Overall, the particle size distribution is similar to, or slightly coarser than loess in the Matanuska Valley of southern Alaska (Fig. 2) where it is found $3 to 7 km from its probable sources (Muhs et al, 2004). This is consistent with an interpretation that the nearby Copper River and its tributaries were the immediate sources of aeolian sediment at Chitina.…”

Section: Wrangell Mountainssupporting

confidence: 82%

“…Stratigraphy, radiocarbon ages, and coarse silt, fine silt, and clay contents in the Chitina loess section. Shown for comparison (gray bands) are the ranges of silt and clay in loess $3 to $7 km away from sources in the Matanuska River valley, southern Alaska (Matanuska data from Muhs et al, 2004). and the fraction of the mineral matter that is capable of long-range transport (<20 lm).…”

Section: Wrangell Mountainsmentioning

confidence: 99%

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Loess origin, transport, and deposition over the past 10,000years, Wrangell-St. Elias National Park, Alaska

et al. 2013

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a b s t r a c tContemporary glaciogenic dust has not received much attention, because most research has been on glaciogenic dust of the last glacial period or non-glaciogenic dust of the present interglacial period. Nevertheless, dust from modern glaciogenic sources may be important for Fe inputs to primary producers in the ocean. Adjacent to the subarctic Pacific Ocean, we studied a loess section near Chitina, Alaska along the Copper River in Wrangell-St. Elias National Park, where dust has been accumulating over the past $10,000 years. Mass accumulation rates for the fine-grained (<20 lm) fraction of this loess section are among the highest reported for the Holocene of high-latitude regions of the Northern Hemisphere. Based on mineralogy and geochemistry, loess at Chitina is derived from glacial sources in the Wrangell Mountains, the Chugach Mountains, and probably the Alaska Range. Concentrations of Fe in the silt-plus-clay fraction of the loess at Chitina are much higher than in all other loess bodies in North America and higher than most loess bodies on other continents. The very fine-grained (<2 lm) portion of this sediment, capable of long-range transport, is dominated by Fe-rich chlorite, which can yield Fe readily to primary producers in the ocean. Examination of satellite imagery shows that dust from the Copper River is transported by wind on a regular basis to the North Pacific Ocean. This Alaskan example shows that high-latitude glaciogenic dust needs to be considered as a significant Fe source to primary producers in the open ocean.Published by Elsevier B.V. IntroductionDust is an integral part of the Earth's environmental systems, including the atmosphere, geosphere, hydrosphere, and biosphere. A number of reviews in the past decade or so have emphasized the importance of dust with its influence on planetary radiation balance, effects on clouds and precipitation, its role in adding nutrients to soils and the biosphere, and the importance of dust as a source of iron to primary producers (such as phytoplankton) in the world's oceans (Kohfeld and Harrison, 2001;Tegen, 2003;Goudie and Middleton, 2006;Mahowald et al., 2005Mahowald et al., , 2006Kohfeld and Tegen, 2007;Maher et al., 2010;Shao et al., 2011;Muhs, 2013a). These reviews also show that the emphasis of dust research has been on either contemporary dust sources, dominantly in low-latitude arid regions, or enhanced dust production at higher latitudes during the last glacial period. There has been a focus on contemporary dust sources at low latitudes because satellite-based global studies show that such regions are unquestionably the most important dust sources at the present time (Prospero et al., 2002). Concentration of studies on mid-latitude and high-latitude dust sources during the last glacial period is also understandable, because dust production globally during this time was much greater than at present, as seen in ice core records (EPICA Community Members, 2004;Ruth et al., 2007), deep-sea core records (Rea, 1994(Rea, , 2007, and loess r...

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Section: Wrangell Mountainssupporting

confidence: 82%

Section: Wrangell Mountainsmentioning

confidence: 99%

Loess origin, transport, and deposition over the past 10,000years, Wrangell-St. Elias National Park, Alaska

et al. 2013

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“…Church (1972) observed aeolian transport of 1600 g m-w month -1 on Baffin Island but 40% of this material was moved in one day. In addition to generating dust storms, aeolian sediments, when deposited, play an important role in proglacial geomorphology, notably as aeolian duneforms (Mountney & Russell, 2009), inputs to soil development and as loess accumulations (Muhs et al 2004). …”

Section: Introductionmentioning

confidence: 99%

Dust generation on a proglacial floodplain, West Greenland

Bullard

Austin

2011

Aeolian Research

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The interplay of glacial dynamics, glaciofluvial and aeolian transport in proglacial landscapes plays an important role in local environmental systems and in the global context by affecting the amount of dust generated and transported at different phases of glacial-interglacial cycles. Glacial outwash plains are a significant source of dust, however the processes involved in dust generation on proglacial floodplains are poorly documented. We report a study of the quantity and characteristics of aeolian suspended sediment transport in Sandflugtdalen, a valley containing a proglacial floodplain and aeolian dunefield in West Greenland. Although the surface sediment of both the floodplain and dunefield contain a considerable amount of sand-sized material, wind speeds recorded were insufficiently strong to mobilise this material; this is probably due to the armouring effect of coarser particles in the surface deposits. Nevertheless, fine (dust-sized) aeolian sediments were transported down valley in suspension and the source of this material was a silt-dominated meltwater deposit up valley from the monitoring sites. Dust transport ranged from 0.0008-0.082 g m-w s-1 over seven days and 0.0035-0.011 g m-w s-1 over a further 57 days during which no additional fluvial sediments were deposited.The reduction in sediment transport rate is attributed to both a depleted sediment supply and a decrease in above threshold winds. The supply of fine sediments to this proglacial region is dependent on meltwater suspended sediment loads which are predicted to increase during glacier retreat; reworking of the floodplain during ice retreat may also make more material available for aeolian transport.

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“…Quaternary deposits of many highmountain areas, such as till, rock glacier deposits, and talus, are often characterized by silt mantles interpreted to be of eolian origin (see review in Muhs and Benedict, 2006). Silt or loess mantles have been described at the margins of, or even outside of the major loess belts of China (Sun, 2002), Europe (Coudé-Gaussen, 1990), New Zealand (Eden and Hammond, 2003), South America (Zárate, 2003), and North America (Muhs et al, 2004a).…”

Section: Introductionmentioning

confidence: 99%

Geochemical evidence for airborne dust additions to soils in Channel Islands National Park, California

Muhs

Budahn

Johnson

et al. 2008

Geological Society of America Bulletin

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There is an increasing awareness that dust plays important roles in climate change, biogeochemical cycles, nutrient supply to ecosystems, and soil formation. In Channel Islands National Park, California, soils are clay-rich Vertisols or Alfi sols and Mollisols with vertic properties. The soils are overlain by silt-rich mantles that contrast sharply with the underlying clay-rich horizons. Silt mantles contain minerals that are rare or absent in the volcanic rocks that dominate these islands. Immobile trace elements (Sc-Th-La and Ta-Nd-Cr) and rare-earth elements show that the basalt and andesite on the islands have a composition intermediate between upper-continental crust and oceanic crust. In contrast, the silt fractions and, to a lesser extent, clay fractions of the silt mantle have compositions closer to average upper-continental crust and very similar to Mojave Desert dust. Island shelves, exposed during the last glacial period, could have provided a source of eolian sediment for the silt mantles, but this is not supported by mineralogical data. We hypothesize that a more likely source for the silt-rich mantles is airborne dust from mainland California and Baja California, either from the Mojave Desert or from the continental shelf during glacial low stands of sea. Although average winds are from the northwest in coastal California, easterly winds occur numerous times of the year when "Santa Ana" conditions prevail, caused by a high-pressure cell centered over the Great Basin. The eolian silt mantles constitute an important medium of plant growth and provide evidence that abundant eolian silt and clay may be delivered to the eastern Pacifi c Ocean from inland desert sources.

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Holocene loess deposition and soil formation as competing processes, Matanuska Valley, Southern Alaska

Cited by 86 publications

References 30 publications

Loess origin, transport, and deposition over the past 10,000years, Wrangell-St. Elias National Park, Alaska

Loess origin, transport, and deposition over the past 10,000years, Wrangell-St. Elias National Park, Alaska

Dust generation on a proglacial floodplain, West Greenland

Geochemical evidence for airborne dust additions to soils in Channel Islands National Park, California

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