Natural History of Salt Point State Park

 

Salt Point State Park’s six miles of rugged, rocky coastline includes a diverse scenery of remote inlets, sheltered bays, abrupt sea stacks, and scattered sandy beaches. But the number one attraction of the park are the unique weathered cavities on the orange sandstone rocks called the tafoni, the Italian word for cavern.

How and why tafoni forms remains a geological mystery. It is believed that they were formed millions of years ago about 260 miles to the south by turbulent underwater ocean currents that deposited mud, sand, gravel, cobbles, and boulders during active phases of seismic activity.

Salt Point State Park spans a section of the San Andreas Fault collision zone between the North American and the Pacific tectonic plates which 25 million years ago began to grind sideways past each other. As a result, the oceanic crust to the west of the Pacific plate has moved several hundred miles northward relative to the North American plate on the east side of the San Andreas Fault forming the uplifted marine terrace landscapes that you see today.

Salt Point is named for the cliffs and crevices of the rocky shoreline where salt from ocean water crystallizes in sandstone depressions. The Native Kashia Pomo gathered salt here for centuries. One of the most unusual and beautiful features of the sandstone along these sea cliffs is the honeycomb-like network called tafoni.

A closer look at Salt Point’s tafoni intricate designs would reveal a resemblance of the Martian surface, where tafoni-like formations were identified by NASA missions. Researchers hope that by analyzing environmental conditions leading to the formation of tafoni on Earth, scientists will help explain surface erosion mechanisms on the Red Planet. On Earth, tafoni can be found on a variety of rock formations, from sandstone to granite, and in a variety of environments, from coastal areas to hot deserts, and even in frozen lands of Antarctica.

Salt Point State Park is one of the few places in California where visitors can see well-developed honeycomb tafoni that reflect the complex interaction between the rock structure and the environmental factors.