Tar Near Pebble Beach and It's Possible Origins

During mid-June, I had the opportunity to spend a couple of days at Asilomar State Beach and Spanish Bay Beach near Monterey, California. The weather was great, the water was beautiful, and there was an abundance of crabs, anemones, and other tidal animals to explore and photograph. However, I was surprised to find tar on both the fine white sand and the jagged granite rising up out of the Pacific. On the beach, there were several small patches scattered along the high-tide line along with the normal kelp and sea grass. I would say that there were approximately 1 – 2 dime sized patches and 2 – 3 smaller patches per yard (about 1 meter). The “tar ball” that I assembled and photographed (see below, right) was made up primarily of the dime-sized patches I found during one walk across the beach.

On the rocks, the sizes of the patches varied significantly and were evenly distributed on the rocks on either side of the beach (see picture below that shows the crescent-shaped beach in between two large clusters of rock). My understanding is that Asilomar State Beach ends at Sunset Drive, which means the sandy beach shown here and the rocks to the south are Spanish Bay Beach. Some of the tar patches were small, similar to the two on the fist-sized chunk of granite shown below. Other patches were approximately the size of a basketball. I found it surprising that tar would be on a beach just a few miles north of some of the most scenic and pristine stretches of the California coast - a stretch that includes both Pebble Beach and Big Sur.

I tried to find any information about recent oil spills in the area and found out that a tug had recently sunk off Point Sur. According to the California Department of Fish and Wildlife (http://www.dfg.ca.gov/ospr/), a tug sank to the south off Point Sur on April 13, 2013. No other information was available, but an environmental assessment of the sunken tug is ongoing. I wondered if the tug, about 25 miles to the south, could have been the source of the tar.

After a little more research, I found a United States Geological Survey (U.S.G.S.) website that indicates that the tar may have originated from natural seeps at the bottom of the ocean somewhere down near Santa Barbara or Santa Maria. A study released in 2007, that contained analysis of tar collected at Asilomar, concluded that the tar likely came from the Miocene Monterey Formation. This formation makes up the majority of the California coastline and contains large amounts of oil and fossils. The U.S.G.S. report can be found at: http://soundwaves.usgs.gov/2007/05/research2.html. Could the tar I collected possibly have made the trip up the coast from Santa Barbara?

As you can see in the pictures, the substance was thick and could easily be picked-up and molded into a ball. However, it did start to get very sticky as it was handled and has been stored in a cool environment since it was collected.

On the 12th, I spent a few hours about 2 miles north looking at the tide pools in Pacific Grove and did not see any tar there. I also spent a few hours at Carmel Beach, about 4 miles south, on the 13th and noticed no patches of tar there either (see photo below, right).

If you have any thoughts about the source of the tar or any photos you would like to share, please post them to the comments section below or email them to me at morrism@memoirstream.com and I will post them here.

By Michael Morris