What You Need and
“Things To Be Aware Of”
There is little room to park at GZ, choose a sensible
location where you can be seen from both directions along the
road. Parking on the north side of the road may be easier but
you'll have to cross it. There is a gateway at roughly S45 55.475
E170 26.065 on the north side of the road but you'll have a wee
walk to get to GZ.
You will need: a camera and a source of acid (a bottle of
vinegar - contains acetic acid should suffice). A ladder and hand
lens aren't essential but could be handy.
Background
The rock that you are looking at is part of a relatively thick
(over 120m) unit that crops out over a 40km coastal extent between
south of Dunedin and Palmerston. This sedimentary rock formed as
the ancient seas slowly receded from the Otago seabed and deposited
the sediment that formed this rock. The quartz here (have a look
with a hand lens) is evidence of Central Otago uplift. This uplift
enhanced the river based erosion of schist, carrying the quartz
here. The amount of quartz ranges from 40-70% at various
depths.
Some sections of this rock yield a rich array of large fossils
but you are more likely to find evidence of smaller fossils such as
foraminifera, ostrocods (shrimp). These appear as white specks in
the rock about the size of a biro nib. Larger fossils can be found
with scrutiny (hence the ladder): bryozoans (eg coral),
brachiopods, pectinids (scallop), oyster, gastropods (snails),
echinoderms (eg starfish). The occasional whale bone has turned up
elsewhere in the formation.
Chert showing foraminiferan fossil
inclusions - Source:
http://users.stlcc.edu/mfuller/petersonclovis.html
A nice sequence of rock formation occurs here: the rock you are
examining is about 17 million years old and behind the road cutting
within the quarry is basalt at about 14 million years in age.
Aerial View - Source:
www.cityofdunedin.govt.nz
Logging
Requirements
0. Preface any email with GC28W5K Fancy Some Fun Fossicking
Fossil Fauna? in the subject line and title and clearly note the
question number and answer. You don't need to wait for a
confirmation email to log but you might be asked for more info if
your answers are slim.
Sedimentary Rock Identification Key.
Source:
http://www.geomore.com/Sedimentary%20Rock%20Chart.htm
1. Use the above key for identifying sedimentary rocks (and your
acid) to find out what type of rock is found at GZ Email the
answer.
2. Use your initiative (and your ladder if necessary) to locate
a fossil in the rock, identify the type of animal as much as you
can. Upload your photo (showing a fossil and your gps and what you
think the fossil is.
2010 Stegan’s
EarthCache Masters Programme
Since it is not very feasible for many NZers to easily get more
than two states for the earthcache.org masters programme and
therefore not get past Bronze I’m running my own one on a
number of Earthcaches that I plan to release this year (all things
being equal) with the following points system:
5 points: First to find
3 points: 2nd to find
1 point: Logging a find
1-5 points: Special bonus questions.
Shared points for joint finds.
At the end of 2010, I’ll issue certificates for 1st, 2nd
and 3rd and the first place getter will be awarded a geocoin. If I
feel richer and/or it looks like this is popular I’ll upgrade
the prizes.
Updated information and Leaderboard at: Stegan’s
Earthcache Programme