Pelagic Sediment


Montana del Oro is the “Mountain of Gold,” – a wealth of natural beauty and wildlife.  The park’s name, “Mountain of Gold,” comes from the golden wildflowers that bloom in spring.  The size of this State Park is over 8000 acres, including seven miles of shoreline.  This makes Montana del Oro one of the largest state parks in California.  The prevailing rock of the park is Monterey Shale.  Formally ancient sea floor, it is composed of mudstone deposited millions of years ago when the fragments of once-living organisms drifted to the bottom and mixed with silt and sand.  The mud solidified into thick layers of diatomite, clay porcellanite, dolomite, and chert.  The road that you take to the park entrance is extremely curvy.

.3 miles on the left eucalyptus grove.

     The eucalyptus trees were planted in the 1940’s by Alexander S. Hazard to cash in on California’s growing need for timber, unfortunately eucalyptus is unsatisfactory for commercial use.

.7 miles there is a road that grants you access to Sand Split.

     The Sand Split is a long finger of sand that separates the ocean and the Morro Bay Estuary that you can walk for miles on.

1.6 miles there is access to the dunes.
2.5 miles there is access to the beach.
2.7 miles into the park is the Hollow Way Trail.

     As the Hollow Way trail begins you can see cliffs and the beach on the right and a sage field on the left.  The trail continues along the edge of the cliff, but there are wooden rails for your protection.  At the first overlook on the right you can see a nice outcrop of the Monterey Shale covered by a conglomerate marine terrace.  This is an example of an angular unconformity with a tilt of about seventy degrees.  The trail continues along the edge of the cliff.  At the point where the trail starts to veer left away from the cliffs there are eroded channels to the right.  The trail then forks and you make a left down the hill.  As you go down the hill and look to the left you can see an outcrop that is matrix supported made up of angular clasts, possibly the result of a slump.  At the bottom of the stairs turn right and you are on a beach facing the ocean.  When facing the ocean there is a channel at your back.  A channel is a bed where a natural stream of water runs.  The beach is covered with kelp, muscles and chert stones.  As you move further away from the water there is finer sediment possibly a mixture of sediment from the channel and the ocean.  There are also some stones with boring holes in them.  Borings are holes made by animals into hard material, such as wood, shells, rock or hard sediment. Borings are usually circular in cross-section.
Two possible birds that you might see are White Pelicans and the black birds are Cormorants.  Along the trail you will also see a yellow flower Fennel, if you rub this in between your fingers it smells of licorice.  At the beginning of the trail on the left is the Hollow Way Garden a fenced in garden made up of indigenous plants.  The eucalyptus trees that you see are not indigenous to this area.  The fog might be an issue if you arrive in the morning; the rate of visibility is probably much higher in the afternoon.
 
 


Pelagic Sediment in Montana del Oro State Park, California

More Pictures


References:

http://gpc.edu/~pgore/geology/historical_lab/sedstructureslab.php
http://santalucia.sierraclub.org/mntdeoro.html

Back
Home

Created by:  Mollie Laird
Last Updated:  December 2003