Rock Products

MAY 2018

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72 • ROCK products • May 2018 www.rockproducts.com LAST CALL Based on modern estimates, an active human will take more than 224,000,000 steps over a lifespan of 65 years based on an average of 9,448 steps per day. Most footprints that result from these steps are ephemeral, poorly defined and disap- pear quickly. In some cases, a distinct cast of the foot is left in soft sediments, preserving a representation of the foot and motion of the individual in solid rock. Although found in many different types of sedimentary contexts worldwide (for example in cave floors and volcanic ash), a high proportion of hominin trackways have been discovered in near- shore settings. When it comes to footprints, coastal settings are unique in some respects in that they are places where exposed soft and semi-saturated sediments abound, and they are linear focal regions for human and animal activity. Calvert Island, near Vancouver, Canada, is situated between two areas of vastly differing sea level history. After 14,500 years ago, sea level dropped rapidly on the mainland and rose rapidly on the outer coast, but remained relatively stable in between these two regions. On Calvert Island sea level was 2 to 3 meters lower than today between 14,000 and 11,000 cal BP. Unexpectedly, a series of human footprints were found while testing depos- its under a beach on Calvert Island. The footprints are more than 13,000 years old, making them the oldest ever found in North America. The footprint measurements correspond to modern-day U.S. shoe sizes of a junior size 8, a junior size 1 or woman's size 3, and a woman's size 8-9, or man's size 7-8, according to the researchers. The field team that found the footprints included several archaeologists, students from the University of Victoria, as well as representatives from the Heiltsuk First Nation and the Wuikinuxv First Nation. A scientific study of the footprints – "Terminal Pleistocene Epoch Human Footprints From The Pacific Coast Of Canada," by Duncan McLaren, Daryl Fedje, Angela Dyck, Quentin Mackie, Alisha Gauvreau and Jenny Cohen – was published on PLoS ONE and can be accessed at http://journals.plos.org/ plosone/article?id=10.1371/journal.pone.0193522. Oldest Footprints in North America Found in Rock "In the practice of archaeology there are multiple levels of evidence indica- tive of past human activity." By Mark S. Kuhar

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