Characteristics of modern atmospheric dust deposition in snow on the Penny Ice Cap, Baffin Island, Arctic Canada

We evaluated the concentration, size and distribution of insoluble dust microparticles in snow-pits on the Penny Ice Cap (PIC), Baffin Island, to define (1) the characteristics of modern atmospheric dust deposition at the site (2) the relative contributions of proximal and distal dust sources, and (3) the effects of summer melting on depositional signals in snow. The mean concentration (143 μg/kg -1 ), flux (4.8 μg cm 2 yr -1 ) and diameter (2.3 μm) of dust deposited on the PIC are similar to those observed in remote Arctic sites such as central Greenland, implying that dust is primarily supplied through long-range transport from far-removed source regions (at least 102-103 km distant). There is evidence for two seasonal maxima of dust deposition, one in late winter-early spring and one in late summer-early fall, although seasonal signals can not always be resolved in the snowpack due to some post-depositional particle migration with summer melt. However, ice layers appear to limit the mobility of particles, thereby preserving valuable paleoclimatic information in the PIC ice core dust record at a multi-annual to decadal temporal resolution.