Monterey Days
The foredunes surrounding Asilomar (see below)
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Asilomar and most of the Monterey area coastline is formed by Santa Lucia granodiorite, a rock that is over 100 million years old. Formed from a molten mass deep in the earth, this dense, hard rock is comprised of large rectangular crystals of orthoclase feldspar, gray translucent quartz, creamy plagioclase feldspar, and black biotite mica. It was exposed through massive uplifts and then transported here by the action of plate tectonics. This movement most likely caused the cracks you see in the rocks. The cracks weaken the integrity of the rock, making it more vulnerable to erosion.
Erosion is an ongoing process at the coastline. Severe winter storms generate large waves that sweep the quartz sand from the shoreline and into the ocean where it forms sandbars in the water just off shore. In spring, the gentler waves redeposit this sand onto the beach. In late spring, the winds blow the sand farther inland where it is caught by plants in the first set of dunes called “foredunes.” With a large supply of sand held in the foredunes, a balance between beach erosion and deposition can be maintained over time. To protect the sandy soil from wind erosion and to provide a habitat for plants and animals, the coastal bluffs at Asilomar are planted and maintained by the park staff.
The sandy beaches may seem devoid of life, but underground there is an army of marine organisms. Worms, crabs, and tiny invertebrates dwell in the first six to eight inches. Some are so small that they can live in the tiny spaces between the grains of sand. They are nourished by plankton and dissolved oxygen that the seawater carries in its waves.