Hidden Gem: Most Drivers Overlook This Stunning Black Sand Beach in the Bay Area

A Californian shoreline lies at the end of a narrow, one-lane street. Marin Headlands While visitors frequently miss this detail, black sand beaches are commonly linked to locations like Iceland and Hawaii , the Bay Area has one for itself.

You'll need to make your way through a dense layer of San Francisco fog , scale down 391 steps and time a visit to avoid king tides in order to see Black Sands Beach for yourself.

This part of the Golden Gate National Recreation Area is already a haven for hikers, thanks to its proximity to nearby areas. stunning views and secluded hikes However, a geological wonder at the shore happens to be the least visited beach in the Marin Headlands, as stated by recreation area ranger Vassar Terry.

“She mentioned during a recent phone interview with GudangMovies21 that people aren’t truly aware of it.”

Hidden away and scarce, this particular stretch along the Marin coastline stands out as one of just a handful in California designated as a "black sand beach," making it uniquely the sole such site within the Bay Area. The distinction comes from these beaches needing to have an exclusive kind of submerged stone which transforms into jet-black sand through eons of erosion.

What is pillow basalt?

The rocks in the Marin Headlands are known as a geological wonder called the Franciscan Complex. Terry mentioned that geologists come from all over the globe to examine its distinctive formations, sediment layers, and exceptional intricacies.

As noted by Doris Sloin in her work "Geology of the San Francisco Bay Region," the rocks originated hundreds of millions of years ago due to shifts in tectonic plates throughout history. The Franciscan Complex consists primarily of three types of rock: red-brown sedimentary rock known as radiolarian chert, which can also be observed on Twin Peaks; a type of sandstone referred to as graywacke; and pillow basalt, a volcanic rock that contributes to the formation of black sands.

In the Marin Headlands, "outstanding examples" of pillow basalt can be found, according to Sloan. This formation is fundamentally "old ocean floor," made up of basaltic lava flows along with what is known as pillow lava. These formations appear across the Bay Area at locations such as the Nicasio Reservoir and Mount Diablo. The pillow basalts are quite dark in color, whether they remain solidified rocks or weather down into sand over extended periods.

"Much of the California coastline consists of ancient seabed materials," stated Gary Griggs, who is both an author and a professor specializing in earth and planetary sciences. at UC Santa Cruz .

Griggs gathered sand samples from "hundreds" of beaches around the globe and has extensive knowledge about the black sands found in Iceland and Hawaii. Less recognized black-sand shores can be spotted in Humboldt and Mendocino counties; however, their darkness pales compared to those more famous locations.

‘Pretty rare’ in California

"There are few locations where pillow basalt serves as the sole source of sand," Griggs stated.

Although many of the shores within the Marin Headlands contain traces of pillow basalt mixed with their sands, the beach known as Black Sands stands out due to its noticeably darker hue compared to nearby locations such as Kirby Cove or Rodeo Beach.

Joe Street, who manages the Energy, Ocean Resources and Federal Consistency Division at the California Coastal Commission, mentioned that it's uncommon to find a beach along California’s coastline featuring such an extensive presence of pillow basalt.

“It’s quite uncommon in California,” he stated. “If there is any kind of basalt-like sand present, it usually gets mixed with and diluted by other types of sand found along the shore.”

How to get there

Griggs pointed out an additional feature that sets Black Sands Beach apart: It’s only a half-day journey from San Francisco. "There's no need to travel all the way to Iceland," he remarked. "You can experience this right in your own neighborhood."

The brief route to the beach can be discovered just west of the busy viewpoint overlooking the Golden Gate Bridge along Conzelman Road.

Leave Alexander Avenue from Highway 101, proceed through the Baker-Barry Tunnel, and follow the curving path uphill towards the rear section of the Marin Headlands. Afterward, make a right onto Conzelman Road; continue along this route as it narrows down to a single lane until you reach a modest parking area.

Terry remarked, "It's hard to know where this trail leads, which keeps the beach quite secluded. The entire hike consists of steps. This isn't usually everyone's preferred trek when starting from the Marin Headlands."

You certainly fit in your daily cardiovascular exercise by tackling approximately 400 steps each direction, which equates to roughly a quarter-mile trek.

If you fall down, you must climb back up," Terry stated. "However, it’s worthwhile.

Timing and weather are crucial factors. It’s wise to check the tides ahead of visiting.

In the wintertime during king tides, the beach occasionally narrows down to just a thin strip of sand. Although fires and pets aren't permitted here, admission remains free and access is unrestricted at all times. "This spot offers one of the scarce examples of a black sand beach in California," noted Griggs. "And best of all, visiting won't cost you anything."