The rocks exposed at Newport Landing belong to the Windsor Group,
deposited in the Windsor Sea about 340 to 325 Ma. That was during
the Carboniferous Period. During Windsor ea times, Nova Scotia lay
a few degrees south of the Equator, so the climate was hot. It was
also dry. The dryness was because the area was part of the
supercontinent Pangea and was in a rain shadow. This meant that
rocks such as gypsum formed as the waters of the Windsor Sea
evaporated periodically. If one heats 1 litre of seawater, gypsum
will precipitate after about 800 ml has been evaporated; salt will
only appear after much more of the water has evaporated.
Exposed in the section before you is a reef, which is faulted
against a mass of gypsum. Most reefs today are formed from coral
but this one is a shellbed or coquina; that means it is made of
millions of shells, in this case snails or, to use the fancy name,
gastropods. Other organisms that can make reefs include bryozoans
and algae.
Most reefs are limestone or calcareous rocks and most consist of
two main parts. The first is the base, a layer that can stretch for
many kilometres and is called the biostrome. The upper part where
most of the organisms live and where the shells “float” in a
limestone cement is the bioherm and is akin to the high-rises in a
city. As with high-rises, the popular side of a reef is the seaward
side, for that is where most of the food is found.
At the cords you will see thousands of shells arranged into
three biostromes and three bioherms. Look at the shells carefully
and notice that the insides are hollow. Such cavities or the spaces
between individual mineral grains in rock are its porosity, an
important factor when we are looking for water, oil and natural
gas. Another vital property is permeability. The degree of
permeability controls how quickly fluids or liquids can migrate
through a rock. Rocks, such as reefs, with high porosity and
permeability make ideal reservoir rocks for oil and natural
gas.
A Windsor age biostrome in the Coquina Reef at Newport Landing
shows the thousands of shells touching each other. The darker spots
are the chambers in the snail shells that are not filled in; they
are the porosity of the rock, and are about 30 to 50 % of the
volume.
To claim
the earthcache you must send me the answers to these 4
questions.
1. Why don't reefs grow in the Bay of Fundy now?
2. What was the main food source for the snails?
3. What is the name of a reef that was discovered on the Scotia
Shelf that holds alot of natural gas and oil?
4. What is the total length of the coral reef that is exposed at
this site?
To prove you where at the site please take a picture of your
group & gps with reef in the background.
You do not
need to wait for confirmiation from me before posting online.
However, any logs that do not fulfill ALL requirements will be
deleted.
Since you have to watch for the tides, make sure you go into the
Shipyard Museum and ask the nice folks what the tide times are.
Bring boots because most likely it'll be muddy.