Dr. Robert R. Gaines will present his talk titled:
A remarkable new fossil assemblage from the Burgess Shale and the early history of complex life on Earth
Between approximately 600 and 520 million years ago, Earth experienced a series of radical changes that permanently transformed the planet. These events, driven by evolutionary innovations, were of sufficient magnitude that geologists divide Earth’s entire 4.6 billion year history into two fundamental parts, the Precambrian and Phanerozoic Eons. The “Cambrian Explosion” of life that defines this transition involved the origin and rapid expansion of complex life, the shift from an entirely microbial world to one dominated by multicellular organisms, the origin of animals, and the advent of predation and complex ecosystems.
Our best record of the Cambrian “explosion” comes from a handful of extraordinary fossil deposits that preserve the “soft”, labile tissues of extinct animals in addition to the mineralized shells, teeth, and bones, of which the fossil record is almost exclusively comprised. Best known among these is the Burgess Shale, discovered in 1909, which revolutionized our understanding of the emergence of complex life. In 2012, an extraordinary new soft-bodied fossil assemblage from the Burgess Shale was discovered in Kootenay National Park, some ~40 km SE of the type area at Field, British Columbia. Despite its geographic and temporal proximity to the Walcott Quarry biota, the Marble Canyon assemblage is distinct, and offers new insights into evolution of complex life on Earth during the Cambrian explosion. This talk will provide an overview of the Marble Canyon biota, as well of ongoing work concerning its geographic extent, paleoenvironmental setting, and the development of the Cathedral Escarpment in the Kootenay area.
Robert R. Gaines, Ph.D.
Bob Gaines is an associate professor of Geology at Pomona College in Claremont, CA. His research focuses on the Cambrian Explosion, the flowering of complex life on Earth during the Late Neoproterozoic and Cambrian Periods some 570 to 500 million years ago. Bob works on the Burgess Shale and many other deposits like it that contain an unusually-rich fossil record of this event. He is also interested in microbial-mineral interactions as a link between the geosphere and the biosphere. He studies ancient sedimentary rocks in South China, British Columbia, Morocco, South Australia, and across the USA, especially the Great Basin.
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