Lecture 5 Fossils

Question 1

fossil

Answer 1

evidence of past life, preserved in materials of the earth’s crust (sediments & volcanic ash deposits)

must be pleistocene or older

Question 2

body fossils

Answer 2

all/part of a preserved organism

Question 3

trace fossils (ichnofossils)

Answer 3

recorded behaviour/activity of an ancient organism

Question 4

6 examples of trace fossils

Answer 4

footprints

skin/feather impressions

tooth marks

eggs/nests

coprolites (poop)

gastroliths (stomach)

Question 5

how is a body fossil made?

Answer 5

1. organism dies, soft tissues rot
2. relatively quick burial to preserve parts(sediment/volcanic ash is key)
3. mineralization of bones & teeth

Question 6

permineralization

Answer 6

when much of the bone/teeth material are replaced molecule by molecule by dissolved ions in ground water

Question 7

strata

Answer 7

layered rocks (eg sedimentary rock, lava flows, volcanic ash deposits)

Question 8

principle of superposition

Answer 8

layers (of rock) closest to the surface are youngest and get older with depth

Question 9

how to tell age of fossils?

Answer 9

using radioisotopic decay methods

eg magma crystalizing forms granite
lava flows form basalt
volcanic ash lithifies into a rock called tuff

calculate by a constant with daughter isotope

bracket age of the rocks surrounding it SQUEEZE THEOREM

Question 10

where is Tumbler Ridge located?

Answer 10

Peace Region, northeastern BC

Question 11

why is Tumbler Ridge so special?

Answer 11

it was a swampy coastal forest which left rare conditions

left behind footprints and bones, as well as an articulated hadrosaur

Question 12

jacketed

Answer 12

when dino fossils are too large and fragile to be removed as one piece

wrapped in plaster instead while surrounding rock is removed