Handling artefact box sponsored by:
Altogether Archaeology
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Fossils = traces of once-living animals and
plants left in sedimentary rock
Images: Creative Commons (see References)
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Igneous rock = cooled lava/magma from
volcanoes
Sedimentary rock = the igneous rock
weathers into little grains like sand, which are
washed away by water and settle in layers at
the bottom
Metamorphic rock = sedimentary rock
changes into metamorphic rock under a lot of
heat or pressure over a long time
What happens in between?
Image: Openclipart.org
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After death, the body is quickly buried under
a layer of “sediment” (mud or sand, perhaps
at the bottom of a lake)
Image: Openclipart.org
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The soft parts of the body decay first, leaving
behind the hard parts (the bones and teeth).
This is a skeleton, but not yet a fossil.
Image: Openclipart.org
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The bones decay and disappear too. The
sediment around them hardens into rock. The
shape of the bones survives as an empty void
or “mould” fossil.
Image: Openclipart.org
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Water flows through the “mould” fossil, and
leaves behind minerals which fill up the mould
and become a “cast” fossil – it is shaped like
the bones, but is made of minerals.
Image: Openclipart.org
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Trace fossils
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Coprolites
Images: Openclipart.org
Images: Creative Commons (see References)
Images: Creative Commons (see References)
Images: Creative Commons (see References)
Today
The past
Images: Creative Commons (see References)
Today
The past
Images: Creative Commons (see References)
THE RULES
1. Layers start out flat
2. Older = deeper, Newer = shallower
3. Layers get thinner to their edges
4. A layer that cuts another layer, is
younger than that layer
This is a RELATIVE chronology – we infer
AGE by the stratigraphic relationships
Image: NNPA
Image: NNPA
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All living things absorb Carbon-14
from the atmosphere while they
live.
Image: Openclipart.org
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When the organism dies, the carbon-14
atoms in its body begin to decay (disappear).
Image: Openclipart.org
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The longer an organism has been dead, the
more Carbon-14 it loses. Archaeologists can
measure how much carbon-14 is left to find
out when the creature died.
Image: Openclipart.org
Creative Commons images
Fossil Fern, Licensed under Public domain via Wikimedia Commons URL:
http://upload.wikimedia.org/wikipedia/commons/c/ca/PSM_V73_D124_Fossil_fer
n_phegopteris_guyottii.png Accessed 18 September 2014
 Fossil Skull: "Homo habilis-KNM ER 1813" by José-Manuel Benito Álvarez
(España) —> Locutus Borg - Own work. Licensed under Public domain via
Wikimedia Commons. URL:
http://commons.wikimedia.org/wiki/File:Homo_habilisKNM_ER_1813.jpg#mediaviewer/File:Homo_habilis-KNM_ER_1813.jpg Accessed
18 September 2014
 Fossil Coprolite (poo): By Linda Spashett Storye book (Own work) [CC-BY-2.5
(http://creativecommons.org/licenses/by/2.5)], via Wikimedia Commons. URL:
http://upload.wikimedia.org/wikipedia/commons/4/48/Lloyds_Bank_coprolite_0
03.jpg Accessed 18 September 2014
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Creative Commons images
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Layered compost bin, by Bruce McAdam from Reykjavik, Iceland (Compost
Uploaded by BruceMcAdam) [CC-BY-SA-2.0
(http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons. URL:
http://upload.wikimedia.org/wikipedia/commons/8/84/Compost_bin_cutaway_b
y_Bruce_McAdam.jpg Accessed 18 September 2014.
Stratigraphy in an excavation trench, Layers visible in a section of an
excavation trench outside the temple of Amun at Karnak, by Hannah Pethen
2011. (c) Hannah Pethen 2011, shared under an Attribution-ShareAlike 2.0
Generic (CC BY-SA 2.0) license, some rights reserved. URL:
https://www.flickr.com/photos/hannahpethen/6822017376/ Accessed 18
September 2014