BURGESS SHALE Kelly Lekan November 19, 2007 GEO 401

LOCATION British Columbia, Canada Yoho National Park

GEOLOGY Cambrian period –~505 million years ago Once located on the Western edge of Laurentia –Was near the equator –Environment was a warm, shallow marine environment where light could easily penetrate the area.

GEOLOGY Found within the Stephen Formation –Located between Mount Wapta and Mount Field. Two major quarries –Walcott quarry (Named for founder of the Burgess Shale Charles P. Walcott) Contains the Phyllopod Bed Most famous fossil collecting site –Raymond quarry

WALCOTT QUARRY

PRESERVATION Deposited in a deep- water basin adjacent to an algae reef Turbidity flows and mudslides transported and buried the organisms –Anoxic environment –Rapid burial –Killed instantly –Not in life position

PALEONTOLOGY The best record we have of Cambrian animals –Most diverse and well-preserved fossil localities –Soft body preservation

PALEONTOLOGY 60,000 unique fossils have been collected 140 species 119 genera ‘Weird wonders’

PALEONTOLOGY Dominated by arthropods Sponges, worm-like phyla, brachiopods, echinoderms, chordates, and mollusks 13 different genera of trilobites Diversity of life –Benthic (lived in the substrates in the bottom of the ocean) –Active and passive suspension feeders, deposit feeders, scavengers, active predators –Free swimmers and bottom dwellers Bottom dwellers moved by either burrowing or crawling Microfossils –Bacteria, protists, cyanobacteria, and dinoflagellates Macroscopic algae

PALEONTOLOGY Well preserved exoskeletons, limbs, and infillings of the gut Soft tissue and muscles Phyllopod Bed Dark Stains –Radioactive carbon

EVOLUTION Best record of Cambrian animals Cambrian explosion – million years ago –Appearance of many new organisms –Soft bodied organisms ‘Taphonomic Window’ –“Historical snapshot in the diversity of ancient life”

SIGNIFICANCE Best record of Cambrian animals Best record of soft body preservation Evidence of Cambrian explosion Evolution from pre-Cambrian life forms Diversity of life –Modes of life/adaptation –Body plans

REFERENCES AND IMAGES HPVM: Hooper Virtual Paleontological Museum. Burgess Shale: Hidden Treasure in the Canadian Rockies. MacRae, Andrew. Burgess Shale Fossils. Rivera, Alexei A. Fossil Lagerstatten: Burgess Shale. Department of Earth Sciences. University of Bristol. ml. ml Smithsonian: National Museum of Natural History. The Burgess Shale: Strange Creatures – A Burgess Shale Fossil Sampler. Trilobites. Trilobites of the Burgess Shale, Canada. UCMP Berkeley. Localities of the Cambrian: The Burgess Shale.