ESM captions JOPL 1699R1

ESM1 Topographic maps showing the settings for Marshall and HiddenLakes

ESM2 Activity of 239+240Pu in Becquerels/kg vs. depth for MarshallLake sediment. Errors bars represent the standard deviations of three replicate ICPMS measurements of the individual extract

ESM3 Magnetic property data (organic-matter-free basis) on sediments from Marshall and HiddenLakes

ESM4 Summary of chemical and magnetic property results (organic-matter-free basis) on sediments from Marshall and HiddenLakes

ESM5 Depth plots for organic matter and selected elements (organic-matter-free basis) for sediments in MarshallLake

ESM6 Depth plots for organic matter and selected elements (organic-matter-free basis) for sediments in HiddenLake

ESM7 Summary of particle-size analyses for sediments from Marshall and HiddenLakes

ESM8 Ternary diagram for La-Sc-Th in lake sediments (MarshallLake, circles; HiddenLake, squares); bedrock lithic types; and dust and loess samples. Lake sediment values plot in a tight cluster. Shaded (open) symbols denote bedrock around Marshall (Hidden) Lake (triangles, arkose; inverted triangles, quartzite; diamonds, shale). Open hexagonal symbol represents the average value of modern Mojave Desert dust (Reheis et al. 2002; Reheis, 2006). Hexagonal symbol with cross inside denotes average value from loess in the Mississippi RiverValley (Muhs et al. 2007). Bold cross denotes upper continental crust (UCC) value from McLennan (2001); small plus symbol (+) denotes Saharan dust (Muhs et al. 2007); large X denotes Asian dust (Zdanowicz et al. 2006). Zdanowicz et al. (2006) did not report Th; Th illustrated here was calculated by J. Budahn (2008, written comm.) using Th/U ratios from the UCC data. Data for bedrock, with the exception of a few samples, are distinct from those for tightly grouped lake sediment and show the relative enrichment of Th, and secondarily La, at the expense of Sc, compared with a composition that represents the upper continental crust (UCC from Taylor and McLennan 1985; McLennan 2001). Also shown for comparison are averages for normalized Sc-Th-La data for modern dusts in the Mojave Desert (Reheis et al. 2002; Reheis 2006), Asia (Zdanowicz et al. 2006; see also Jahn et al. 2001), the SaharaDesert (Muhs et al. 2007), and loess of the Mississippi RiverValley (Muhs et al. 2007). The compositions of the other samples of dust and loess are more similar to the lake sediments than to UMG rocks.

ESM9 Plots of U.S. production of rare earth elements (REEs) and molybdenum (Mo) from mining (Kelly and Matos 2008), with age plots (from 210Pb models) of Y and Mo, respectively, in Marshall (closed circles) and Hidden (open squares) Lakes. Trends in lake-sediment concentration for La, Ce, and Y are closely similar at both lakes. Mining for Mo, the mining began and expanded rapidly during the early 1940s. As with other rare earth elements (REEs) Ce and La, Y increased in the lake sediments at times that generally correspond with the onset of REE mining in the U.S. in the 1950s (Haxell et al. 2002)

References in ESM JOPL1699R1

Haxell GB, Hedrick JB, Orris GJ (2002) Rare-earth elements—critical resources for high technology. U.S. Geol Surv Fact Sheet 087-02

Jahn B, Gallet S, Han J (2001) Geochemistry of the Xining, Xifeng, and Jixian sections, Loess Plateau of China: Eolian dust provenance and paleosol evolution during the last 140 ka. Chem Geol 178: 71-94

Kelly TD, Matos GR (2008) Historical Statistics for Mineral and Material Commodities in the United States: U.S. Geol Surv Data Series 140

McLennan SM (2001) Relationships between the trace element composition of sedimentary rocks and upper continental crust. Geochem Geophys Geosystems 2 doi:10.1029/2000GC000109, 2001

Muhs DR, Budahn J, Prospero JM, Carey SN (2007) Geochemical evidence for African dust inputs to soils of western Atlantic islands: Barbados, the Bahamas and Florida. J Geophys Res 112, F02009,doi:10.1029/2005JF000445

Reheis MC (2006) Sixteen-year record of dust deposition in southern Nevada and California, U.S.A. J Arid Envir 67: 487-520

Reheis MC, Budahn JR, Lamothe P (2002) Geochemical evidence for diversity of dust sources in the southwestern United States: Geochim Cosmochim Acta 66: 1569-1587

Taylor SR, McLennan SM (1985) The continental crust: Its composition and evolution. Blackwell, Oxford. 312 pp

Zdanowicz C, Hall G, Vaive J, Amelin Y, Percival J, Girard I, Biscaye P, Bory A (2006) Asian dustfall in the St. Elias Mountains, Yukon, Canada. Geochim Cosmochim Acta 70: 3493-3507