The
above Co-ordinates take you to St. Anthony Head which has one of
the best views across the Falmouth Ria.
The
Fal Estuary is one of the finest natural harbours in the world, and
has served as a refuge for shipping for thousands of years.
A
drowned river, it now consists of a deep tidal basin opening into
Falmouth Bay fed by numerous rivers and creeks. The estuary is
tidal for a distance of 11 miles inland and has a shoreline
totaling about 71 miles in length.
Human
activity around the estuary probably dates back to the Mesolithic (
or Middle Stone Age ), when the sea level in south west England was
an estimated 35 metres lower than today.
The
geology around the Fal Estuary is dominated by Devonian
metasedimentary rocks, the Carnmenellis Granite to the west and the
St Austell Granite to the east. The shoreline around the estuary is
made up of Devonian metasedimentary rocks. During the Devensian
glaciation (the last glacial period, ending 10,000 years ago), the
sea level would have been much lower and the large scale valley
systems such as the Fal would have extended considerably further
away from our present-day shoreline. These valleys would have been
partially infilled by head deposits. It is also likely that large
scale river systems were present at this time. These river
sediments reworked mineral veins exposed at the surface and the
stable resistant tin mineral cassiterite was reworked and locally
concentrated within these sediments forming placer deposits. These
placer deposits formed the tin grounds which were then worked from
the Bronze Age onwards. At the end of the Devensian glaciation, sea
levels rose and the coastal valleys were inundated by the sea.
Evidence that the landscape would have been wooded at this time
comes in part from the presence of submerged fossil forests and
peat beds around the Cornish coastline. Over the Holocene period
(the last 10,000 years) sea levels initially rose quite rapidly at
about 1m per century, drowning the river valleys to form the
estuary. This type of flooded valley system is referred to as a
ria, which is defined as an inlet formed by partial submergence of
unglaciated river valleys, synonymous with a drowned valley mouth
usually with a branching dendritic or tree-like outline.
The
geomorphology of the landscape around the Fal Estuary is
characterised by steep sided valleys separated by gently rounded
interfluves.
To log this Earthcache we would like you
to -
1.
Complete this sentence. The Falmouth ria/estuary is the ........
largest natural harbour in the world.
2.
Estimate the width of the Ria at this point (if it helps the
co-ords for Pendennis point which is the other side of the ria are
N50 08.644 W005 02.525). Answers in metric or imperial.
3.
Picture yourself and/or GPS with the Ria in the background and post
it with your log.
Please
email us the answers to the above questions. Click on our profile
and then the send a message option to email us your answers.
Feel
free to log your visit before you receive confirmation of your
email. However, logs without corresponding email may be
deleted.
As an
additional requirement, please enjoy the stunning views and
investigate the history of St. Anthony Head while you are here.
