Jack Souther

Jack Gordon Souther (April 25, 1924 – June 1, 2014) was an American-born Canadian geologist, volcanologist, professor and engineer. He contributed significantly to the early understanding of recent volcanic activity in the Canadian Cordillera. Many of his publications continue to be regarded as classics in their field, even now several decades after they were written.

Biography Souther was born in Chicago, Illinois, United States on April 25, 1924. As a young child he moved to the U.S. state of Alabama. In his teenage years, Souther relocated with his family to the Canadian province of Alberta at a cattle ranch near the First Nations settlement of Morley. After his family lost the ranch, Souther moved with his family to the mountain town of Banff. Here, he attended Banff High School. In 1945 at the age of 21, Souther graduated as the class president. He was later accepted into a geological engineering program at the University of British Columbia in Vancouver.

He was offered a full scholarship to Princeton University in Princeton, New Jersey, after excelling to such a degree at the University of British Columbia. Consequently, he enrolled in the Ph.D. program for geology.

Souther had long been in demand as a public speaker because of his ability to communicate scientific ideas to lay audiences. This included his ability to be a principal in media interviews, a participant in radio and television open-line shows and as a main figure in television broadcasts handling with its scientific concentration. After retiring to the position of emeritus scientist in 1992, Souther began his second career as a ski guide/mountain host at the Whistler Blackcomb ski resort. In 1995, he received the Career Achievement Award in volcanology and igneous petrology by the Geological Association of Canada.

During an expedition of the Canadian Arctic in 1963, Jack Souther observed and named two geological formations. The Strand Fiord Formation on west-central Axel Heiberg Island, Nunavut consists mainly of basaltic lava flows and agglomerates. Souther established a type section for this formation near the western tip of the Kanguk Peninsula. The overlying Kanguk Formation was named after its locality. It comprises dark grey shale and siltstone with subordinate sandstone and some local thin bentonitic and tuffaceous beds.

In 1965, Canadian geologist John Oliver Wheeler foresaw the need for a volcanological program in Canada's western Cordillera. Souther was given the job of working on the Mount Edziza complex with the able assistance of Maurice Lambert. By 1970, the two geologists had established that eruptions of alkali basalt, followed by extrusion of silicic peralkaline lavas, had occurred episodically at Edziza for the past 10 million years and that volcanism was accompanied by east-west extension and incipient rifting. However, the regional tectonic context was still unresolved. Edziza remained a significant study area for Souther until his last year of serious field work in 1992. During this year he highlighted the importance and size of the region and proposed that numerous eruptions emplaced lava in a sub-ice or ice-contact environment. This was confirmed by other scientists in 2006. He was surprised by the difference in volcanic style between the Wrangell lavas where an enormous volume of andesite lava had issued without any apparent breaks and was accompanied by profound tectonic uplift and compressive folding, in contrast to the episodic eruption of alkaline basalt and highly fractionated silicic peralkaline rocks at Edziza. The differences in eruptive style and chemistry of the Wrangell lavas led Souther to speculate they were related to a calc-alkaline volcanic arc that formed along a converging plate boundary. Souther conducted the first detailed study of Mount Cayley itself during this period. At least three stages of volcanic activity were identified at the volcano. He also hypothesized that the Ember Ridge domes shared a common magma source. However, significant variations in the percentage of phenocrysts in the six domes prove otherwise.

Jack Souther added several hundred Quaternary aged volcanoes on Canadian maps throughout his career. His work contributed to the closing of Canada's gap in the Pacific Ring of Fire.

The most common rocks, andesite and dacite lavas, were said to have been deposited when volcanic activity created a series of islands and lava flows in the ancient ocean. Once the shale and lavas were deposited, they began to deform, crumple and uplift due to the extreme pressures created by movement of the North American Plate and the tectonic plates under the Pacific Ocean. The large masses of solidified lava that formerly created the volcanic island chain and underwater lava flows yielded by demolishing into massive, mountain-sized blocks while the less dense, thinly layered shale was compressed, folded and crushed between the associated lavas. Souther classified these rocks as part of the Gambier Group, a geologic formation that was created within a shallow underwater basin about 100 million years ago during the Early Cretaceous period.

The green Piccolo Summit consists of lava flows that Souther speculated to have erupted about 100 million years ago.