Hello, and welcome to the Oceano Dunes
State Vehicular Recreation Area!  My name
is Francesca, and I work for California
State Parks.
Take a look around and notice all of the
sand here in these Coastal Sand Dunes.
The dune habitat is made up of millions
of tiny pieces of sand that pile up to
form hills. Some dunes can be over 50
feet tall. Now you're probably wondering
where exactly does all of this sand come
from? And how are these huge dunes
created? In order to understand how dunes
are formed, we must first figure out
where this sand originates. Many people
think sand comes from the ocean because
after all- these coastal dunes are right
next to the beach.  But would you be
surprised to learn that the sand
actually originates from a location
hundreds of miles away from here? Let's
learn about the rock cycle and the long
journey that the sand has traveled
before settling here at the Oceano Dunes.
Here in California large mountains exist
inland from the coast. These mountain
ranges lay parallel to the Pacific Ocean
and are formed by layers of cooled magma
also known as "igneous rocks."  High up in
these mountain ranges in central
California, granite rocks and sandstone
boulders dominate the landscape. Rivers
and creeks are formed around these large
rocks. When it rains high up in the
mountains,
the strong force of the water flowing
down the rivers causes the rock to erode
into smaller rocks. "Weathering" is when
these rocks get rained on the rain and
the processes up in the creek turn these
large rocks into slightly smaller rocks.
The smaller rocks then turn into smaller
tinier rocks, and eventually as the
process continues and as the creek winds
its way down through the mountains and
out onto the beach, you end up with tiny
rocks known as sand. Now here we have the
Arroyo Grande Creek flowing out in to
the Pacific Ocean and as you know those
rocks were broken up into tiny air
pieces tinier rocks small sand particles.
The sand particles are now washed out
through the creek and in to the ocean.
Those sand particles then settled just
offshore creating what's known as
"sandbars." These sandbars sit in
relatively shallow water and as the surf
comes crashing up over the sandbars, tiny
sand particles make their way back up on
to the beach. Now once that sand is on
the beach, then it's going to take a
journey to up onto the coast to create
the sand dunes. The sand particles
continue to travel in the wind in an
eastward on shore direction. The sand
will continue to travel until it runs in
to an obstacle. The obstacle could be the
shape of an existing sand dune and then
the particle just ends up on it and
keeps accumulating or it could be some
of the vegetation that you see up out
here behind me today!
These vegetated areas are very important
for the structure of these dunes because
it gives it some stability sand is
constantly in motion. "Saltation" is the
name of the process for sand being
transported inland by the force of wind.
While the sand is always in motion and
the dunes are constantly shifting, large
dunes are not created overnight. This
process does take time and can even be
measured on geological timescales! Thank
you for joining me here today at the
Oceano Dunes SVRA to learn about these
amazing coastal sand dunes. To learn more
please follow our Youtube page or check
out our website! Thanks!
