NPS photo

Coastal rocks at Baker Beach evidence of tectonic activity over millions of years

The Golden Gate National Recreation Area is truly a park on the edge, located on the far end of the North American tectonic plate and flanking the Pacific Ocean. Situated above a large subduction zone where planetary crust is driven underground, destroyed, and recycled into new geologic resources, Golden Gate contains a wide variety of geologic features. From the Franciscan complex, representing tectonic events that took place hundreds of millions of years ago. To the Colma formation which tells of a time hundreds of thousands of years ago when San Francisco was an island and the Central Valley of California was an inland sea. To dune sands only a few thousand years old that migrated from the Sierra Nevada Mountains through the Sacramento River all the way to the coast. Whether scraped from the ocean floor under extreme heat and pressure like serpentenite, or built by millions of microscopic sea creatures under time and pressure like radiolarian chert, the Recreation Area has anything a rock lover could want.

Climatic shifts and geologic processes continue to shape this environment as they have for millennia. More recently, human-caused factors such as air, noise, light, and water pollution, have had a much greater impact on natural resources world-wide. The Recreation Area strives to keep a healthy environment for wildlife and world-weary humans alike.