BURGESS SHALE Kelly Lekan November 19, 2007 GEO 401.
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Transcript of BURGESS SHALE Kelly Lekan November 19, 2007 GEO 401.
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
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– 545-525 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. http://park.org/Canada/Museum/burgessshale/tablen.html
• MacRae, Andrew. Burgess Shale Fossils. http://www.geo.ucalgary.ca/~macrae/Burgess_Shale/
• Rivera, Alexei A. Fossil Lagerstatten: Burgess Shale. Department of Earth Sciences. University of Bristol. http://palaeo.gly.bris.ac.uk/palaeofiles/lagerstatten/Burgess/biota.html.
• Smithsonian: National Museum of Natural History. The Burgess Shale: Strange Creatures – A Burgess Shale Fossil Sampler. http://paleobiology.si.edu/burgess/index.html
• Trilobites. Trilobites of the Burgess Shale, Canada. http://www.trilobites.info/Burgess.htm
• UCMP Berkeley. Localities of the Cambrian: The Burgess Shale. http://www.ucmp.berkeley.edu/cambrian/burgess.html.