Massive mud extrusion from numerous mudboils

This is an aerial view from about 70 m altitude of a massive outflow of liquid marine mud which represents coalescing flows from several active mudboils. Ground views of the deposit are shown in images 0096 and 0214. Though this site is north of the tree line, there are scattered stands of spruce in areas with adequate soil moisture, slope stability, and protection from wind, such as along the shores of the lake where this mud burst was observed. Within the continuous boreal forest south of the tree line, mudboils do not form because of the stability of the near-surface soils provided by the trees' root systems. When the trees are sparse, as in these scenes, however, mudboils are common, and in this case quite active. This feature, which I have not seen elsewhere at this scale in this region, clearly confirms that mudboil activity is a thaw-season, or summer, phenomenon. The sediment involved in this outburst is fine-grained marine mud of the post-glacial Tyrrell Sea. The cause of the obviously recent simultaneous outbursts from several mudboils is not evident, but is probably related to abnormal moisture/ground ice conditions during the spring thaw, which have led to liquefaction on this modest slope. The surface of the outburst is corrugated with small ridges reminiscent of congealing or cooling lava flows (see detail in image 0096). See detailed discussion for image 0240.

Updated 05/06/2010 AW