The geology of Point Lobos as it relates to the development of the modern camera
A treatise by S.R. Hinrichs in completion of a B.S. program (sic)
Five camera club members and two associates showed up for this year’s Point Lobos field trip. As usual, the park delivered another spectacular and rewarding day for our participants (in spite of mostly overcast skies).
On last year’s trip we hiked the north side of the point, through forests of Monterey Cypress and Monterey Pine, enjoying the views from various rocky promontories overlooking the rocky coves. We wound up at scenic Whalers Cove before returning to our cars and driving home quite content with our experience.
This year we took the trails to the south and found the general theme of our hike to be all about the geology and birds of the Monterey coastline. This year’s trip also resulted in profound contentment and a late lunch at a restaurant in Monterey. The food was pretty good, but the smarmy waiter deserved a good thrashing! The highlight of the fare was Ted’s coconut pie.
For those who rose early and came with us to climb over, through and around the huge sandstone sandwiches, lantern-jawed faces gazing down into the green pools, frolicking elephants, kissing seals, Egyptian statues, snowmen and other fantasy formations I’ll recount the gripping and steamy saga of the Point Lobos geology.
There are essentially four types of rock formations at Point Lobos: the igneous Santa Lucia Granodiorite; the sedimentary sand and gravel of the Carmelo Formation; the sedimentary rocks formed on ancient marine terraces when the ocean levels were much higher; and the later deposits of gravel and white sand from recent wave erosion.
The saga begins 100 million years ago, according to an account by Daniel Orange of UC Santa Cruz and Keith Simmons of Hartnell College in Salinas. The two professors begin the saga at the beginning of the “modern” geologic period at the end of the Mesozoic era in the middle of the Jurassic period. This was the time when the large species of dinosaurs roamed the surface of the earth—also the first primitive cranes were evolving. Deep in the earth, miles below the volcanoes that dotted the area, molten rock slowly cooled into the Santa Lucia Granodiorite formation, which slowly rose to the surface over the subsequent 40 million years. This formation formed about a thousand miles to the south, but through the motion of plate tectonics, the continental plates rather quickly (in geologic terms) moved northward toward the present location of Point Lobos. The Granodiorite formation (part of something called the Salinian block) was pushed up and exposed to the forces of wind and water erosion.
Then about 60 million years ago, ocean waters filled the Granodiorite canyons and rivers carried lava rock from distant volcanoes in the form of polished round pebbles and cobblestone-sized rocks. Eventually this rock settled at the bottom of submarine canyons and hardened into a conglomerate called the Carmelo Formation. This is perhaps the most interesting rock at Point Lobos because, being softer than the underlying Salinian formation, it was sculpted by the ocean into coves, crevices, shelves—the formations of which seem to watch you with craggy, unmoving faces and empty eye sockets. This formation was taking shape during the Paleocene epoch at the time of the Great Extinction—the end of the line for the dinosaurs. This period also saw the entrance of “Team Mammal” and, about 60 million years ago, our distant ancestor of rats, mice and squirrels were thriving in the absence of the dinosaurs. Meanwhile herons and storks had also evolved. (We saw several of their type from the cliffs overlooking the coves.) After the giant land mammals became dominant and ruled, ten million later, the primitive monkeys showed their curious faces and began contemplating the concept of the camera obscura.
The next geologic milestone event began about 20 million years ago when the tectonic forces on the continental plates moved the formation containing the Point Lobos area another 250 miles to the north—roughly into its present location. Accompanied by the coming the ice ages, which began about 2 million years ago, these rocks were alternately exposed to the weather and covered by the sea as the big freezes played havoc with sea levels. When the sea stayed at one level for long periods, the marine terraces and sloping cliffs along the shoreline of Point Lobos were formed—these are very evident on the south trail of the point where we were. The most prevalent terraces were formed between 35 and10 thousand years ago. Older terraces were formed at a higher level and are exposed in the area up by Highway 1 and slope down through the central portion of the reserve where forests and grasslands exist today. The lowest and most recent marine terrace deposits emerged about 10,000 years ago and sit at an elevation of about 40 feet above the current sea level. The contours around Whalers Cove delineate this ancient shoreline. At this time, during the Cenozoic era, in the Holocene epoch, the species Homo sapiens sapiens (that’s us, baby!) began to form up into permanent settlements and began to experiment with forming soft metals such as copper into pots, tools and camera bodies.
The last chapter in the Point Lobos geologic soap opera happened about 6,000 years ago as the ocean stabilized at its current level and began chewing away at the shoreline. Waves found the weakest points in the faults and fractures in the hard volcanic Granodiorite rock and carved the coves found on the north shore of the reserve. Headland Cove and Whalers Cove are two fine examples of that relentless wave erosion. On the south end of the reserve, at China Cove and Gibson Beach, the beautiful white sand beach deposits are comprised of mineral grains from the Granodiorite formations surrounding the coves. As these beautiful beaches were forming some six thousand years ago, a writing system was being developed in Sumeria. It was at this time that the advanced cultures of our civilization began working on the basis for compiling the camera manuals that we know and love today.
I hope this has been enlightening.
© 2006 S.R. Hinrichs