W. Elliott

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Rainfall and the amount of water available to leach ions from soil are among the most important features determining mineral weathering, secondary mineral synthesis and soil chemical properties. Along an arid to humid climosequence on Kohala Mountain, Hawaii, we sampled 16 soil profiles and found that weathering and soil properties change in a nonlinear(More)
There is evidence that complex objects are decomposed by the visual system into features, such as shape and color. Consistent with this theory is the phenomenon of illusory conjunctions, which occur when features are incorrectly combined to form an illusory object. We analyzed the perceived location of illusory conjunctions to study the roles of color and(More)
Female greater wax moths Galleria mellonella display by wing fanning in response to bursts of ultrasonic calls produced by males. The temporal and spectral characteristics of these calls show some similarities with the echolocation calls of bats that emit frequency-modulated (FM) signals. Female G. mellonella therefore need to distinguish between the(More)
Phosphorus K-edge X-ray absorption near-edge structure (XANES) spectroscopy was performed on phosphate mineral specimens including (a) twelve specimens from the apatite group covering a range of compositional variation and crystallinity; (b) six non-apatite calcium-rich phosphate minerals; (c) 15 aluminium-rich phosphate minerals; (d) ten phosphate minerals(More)
Studies have shown that Bed I and Lower Bed II (1.92Ma-1.76Ma) of Paleolake Olduvai at Locality 80 are primarily composed of the authigenic lacustrine clay minerals illite, smectite, and interlayered illite-smectite. X-ray fluorescence analysis and the sedimentation rates of Hay and Kyser (2001) were used to identify four apparent lake cycles beginning and(More)
Motivated by surface x-ray scattering experiments on homoepitaxially grown Ag(001), scattering models for surfaces having submonolayer coverages are discussed in the context of small angle scattering. It is shown that the surface diffuse line shapes can be interpreted in terms of intra-island and inter-island scattering. The connection between these models(More)
The proportion of authigenic to detrital clay minerals in terrestrial sediments is variable. It has previously been hypothesized that pure Mg-silicates in regions such as Amboseli Basin in Kenya occur due to the absence of Al-rich detritus. We tested this by replicating two Mg-silicate synthesis experiments while adding Al-rich smectite. The first study(More)
  • ROBERT E. JARRETT, Robert E. Jarrett, +4 authors Lawrence M. Kiage
  • 2015
Understanding climatic and water-mineral chemistry affecting hominin habitats during the period 1.92 to 1.80 Ma in Paleolake Olduvai basin, Tanzania is of social and scientific interest. Previous Olduvai research reported climate cycles in bulk sample mineral analyses. X-ray diffraction, X-ray fluorescence, and color analyses of Locality 80 Tuff Bed I(More)