Glacigenic mudflows on the Bear Island Submarine Fan

SeaMARC II sidescan imagery casts new light on glacigenic mass‐wasting on the Bear Island Fan, whose surface geology is evidently much more complex (Figure 1) than the regular bathymetric contours had indicated. The University of Bergen research vessel Håkon Mosby towed a SeaMARC II side‐scan sonar/bathymetric swathmapping system along the Svalbard‐Barents Sea continental margins and across the Mohns‐Knipovich‐Molloy spreading axis [Sundvor et al., 1990] in October and November 1989 and again in September and October 1990. Magnetic, 3.5‐kHz, and gravity data were also collected along parts of the survey area. The plate boundary was the primary campaign target, but significant discoveries were also made on the reconnaissance tracks across and along portions of the margins, mostly below 800‐ to 1000‐m depths (P. Vogt et al., unpublished manuscript, 1993). We summarize our work over the central and northern quadrants of the Bear Island Fan (Figure 2), where the sidescan revealed unusual mass‐wasting in the form of numerous thin (10–20 m), 5‐ to 20‐km‐wide mudflows up to 200 km long (Figures 1,3, and 4).