tracking ancient life dr liam herringshaw lgh865@hotmail.com
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Tracking Ancient Life
Dr Liam Herringshaw
lgh865@hotmail.com
Key terms
Bioturbation
Ichnology
(ichnos, Greek: footprint, track, trail)
Trace Fossils
1. What are trace fossils?
Sedimentary structures produced by life- Burrows, borings, tracks, trails, roots...
...and dung!
The Lloyds Bank coprolite
Why they matter
• Fossil record of behaviour
• Fossil record of soft-bodied organisms
• Organism-environment interactions
• Ecological niche creation
• Nutrient flux
• Taphonomy
Luminous lugworm
UniformitarianismThe present is the key
to the past
Ichnological principles
1. Same organism; different traces
Arthropod trace fossils
Ichnological principles
2. Different organisms; same traces
Annelid wormsSea anemones
Phoronids
Ichnological principles
3. Same trace; different preservation
2. Traces of Yorkshire
What trace fossils does the museum have?
3. Common trace fossils
(Burrows, trails; mostly marine)
Ichnotaxonomy
N.B. Names are for trace fossil only, not organism that made the structure
Planolites
SkolithosSkolithos
Thalassinoides
Thalassinoides tracemaker?
Chondrites
OphiomorphaOphiomorpha
OphiomorphaOphiomorpha tracemaker? tracemaker?
Rhizocorallium
Rusophycus
Rusophycus tracemaker?
Trace fossil?
Impression of a jellyfish?
Or a sand volcano?
Not trace fossils
Shrinkage cracks
Flute castsFlute casts
Not trace fossilsNot trace fossils
Hand Specimens:What Have You Got?
4. The Fossil Record of Behaviour
Earliest animals?
565 Ma locomotion trails,Newfoundland:
Liu et al. (2010)http://geology.gsapubs.org/content/38/2/123.abstract
Ediacaran-CambrianEdiacaran-Cambrianboundaryboundary
Cambrian complexity
The Cambrian Explosion
Seilacher & Pfluger (1994)
Onshore to offshore
Colonization of landColonization of land
Plant Trace Fossils
Becoming upright
Trackway analysis shows tetrapods become bipedal in early Triassic
Kubo & Benton (2009)
http://onlinelibrary.wiley.com/doi/10.1111/j.1475-4983.2009.00897.x/full
The speed of dinosaurs
5. The speed of dinosaurs?
• Type of footprint?
• Footprint size?
• Animal size?
• Stride length?
• Speed?
• Behaviour?
Calculating trackmaker speed
v = 0.25*g0.5*SL1.67*h-1.17
Or, more simply:
Hip height = 4 x footprint length
Stride length/ hip height = speed
(<2 = walking, >3 = running)
Sheffield Geology Group – dinosaur speed calculator:http://www.sorbygeology.group.shef.ac.uk/DINOC01/dinocal1.html
Useful links
www.fossilhub.org
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