Travel Reference
In-Depth Information
Sandstone cliffs tower above the open grasslands and pine-studded meadows of Ventana
Wilderness.
As the denser oceanic plate dove under the lighter continental plate, massive ac-
cumulations of sand, mud, and the skeletons of microscopic sea creatures scraped off
and slipped into a deep undersea trench. The resulting jumble appears along the Big
Sur coast in the Franciscan formation, part of the Nacimiento block, which forms the
underlying rock in the south half of the Santa Lucia Range.
The exposed cliffs at Andrew Molera State Park include excellent examples
of Franciscan rocks. Formed from silica-rich sea creature skeletons, chert features
jagged layering and an erosion-resistant glasslike texture. Sandstone is characterized
by its tan color, rough surfaces, and fine sand grains. Comprising hardened, com-
pressed mud, shale is gray-black in color with microscopic grains.
Serpentine, California's state rock, forms in layers that solidify above molten
rock. These layers are scraped off and jumbled near the surface, where they react with
groundwater to form this slippery green stone. You'll find dramatic serpentine out-
crops in the Silver Peak Wilderness amid the Salmon Creek and San Carpoforo drain-
ages.
Other younger rocks formed in the vicinity of the Santa Lucia Range before a
single peak rose above the surface. A few million years ago, this area was a drainage
basin that collected sediments in the form of sand, silt, and boulders. In time these so-
lidified into sandstone, siltstone, and conglomerate. Conglomerate is least common,
although at Point Lobos it is the dominant sedimentary rock and forms dramatic out-
crops and cobblestone promontories.
While these theories may explain how the rocks formed, they don't explain how
the rocks traveled hundreds of miles and rose to form the Santa Lucia Range. That
story begins along the San Andreas Fault system some 30 million years ago. Once
again, tectonic forces brought oceanic and continental plates together. This time, the
North American plate and the Pacific plate met and began to grind past one another,
marking the San Andreas Fault boundary.
Two massive chunks of Earth's crust, the Nacimiento and Salinian blocks, were
ripped from their moorings along the North American plate and pushed northward
along the numerous major faults associated with the San Andreas system. These faults
generally run northwest-southeast, paralleling the coastline and general trend of the
coastal mountains. A prime example is the Sur-Nacimiento Fault, which separates the
Salinian and Nacimiento blocks, relieving pressure along the San Andreas Fault. As
the tectonic plates collided, compressed, and fractured along these major fault lines,
the land buckled in on itself like folds in a loose carpet, giving rise to the peaks,
ridges, and gorges of the Santa Lucia Range.
