| Dust from Owens (dry) Lake (OdL) is characterized by low concentrations of magnetite and the absence of magnetically hard minerals. Decreasing influence of OdL dust is found in all dust from traps up to 40 km south of OdL within Owens Valley, which agrees well with earlier findings by [Reheis, 1997]. Dust from traps outside Owens Valley shows little influence of OdL dust. It is characterized by high concentrations of magnetite and an additional component of hematite or goethite, and most likely derived from local sources other than Owens (dry) lake. Low field susceptibility (Fig. 2a,b) and remanence parameters (Figs. 2c,4,5) are best suited to distinguish between different dust sources and to estimate the influence of OdL dust. In-field measurements, such as hysteresis loops (Fig.6), are poorly suited for this task. During years of high dust generation from OdL (1993) the magnetic signal of all sites is more diverse than during years of low dust generation from Odl (1997). During these years the magnetic pro perties of all dust samples are more similar suggesting the presence of a well mixed background dust component. |
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