Parking in Malibu Creek State Park requires a fee, but will get you
quite a bit closer to the earthcache. Free parking is available on
surrounding streets, but it gets very crowded on weekends.
The Santa Monica Mountains have only been growing for the past
few million years. Prior to that, the Ancient Malibu Creek had
formed meanders across the prehistoric landscape. The Santa Monicas
began growing as a bend formed in the San Andreas Fault. This bend
causes the North American and Pacific Plates to be slightly pressed
together instead of the just the typical strike slip faulting that
the San Andreas is famous for.
As the mountains were pushed up, Ancient Malibu Creek continued
flowing across the top of the incipient mountain range. The rate of
erosion down into the growing mountains exceed the rate that the
mountains grew up. As a result, the ancient creek meanders were
eroded down into the underlying rock cutting through ridges as they
grew on each side of the creek. Where the surrounding rock is
strong, the creek flows through sheer walled canyons, while wider
valleys form where the surrounding rock is weaker.
The coordinates bring you to an overview of where Malibu Creek
cuts through a ridge of Conejo Volcanics, a well-cemented rock.
Notice that the ridge of Conejo Volcanics runs northwest/southeast
and the creek cuts a U-shaped mender through the ridge heading
south then turns around and cuts back to the northeast (the valley
you most likely hiked up).
This cut through the ridge is the geomorphologic feature called
a water gap. There are additional water gaps both upstream and
downstream in Triunfo Canyon.
On a larger scale, the start of Malibu Creek and its many
tributaries are north of the Santa Monica Mountains. Malibu Creek
then cuts through the Santa Monicas roughly perpendicular to the
mountain range to drain into the Pacific Ocean south of the Santa
Monicas. Malibu Creek cuts a water gap through the Santa Monica
Mountains.
Logging requirements:
Send me a note with :
- The text "GC1BFCR Malibu Creek Water Gap" on the first
line
- The number of people in your group.
- Describe the character of the stream flow west of the primary
coordinates and what happens to the water flow as the stream flows
northeast. What would account for that difference?
- Estimate the depth that Malibu Creek has eroded down through
the ridge. You may want to check out
GC1BFCN for a better view, or walk down to the dam.
The above information was compiled from the
following sources:
- Santa Monica Mountains National Recreation Area
Paleontological Survey, Alison L. Koch, Vincent L. Santucci, Ted R.
Weasma; Geologic Resources Division National Park Service Denver,
Colorado NPS/NRGRD/GRDTR-04/01 2004
- SEISMIC HAZARD ZONE REPORT FOR THE MALIBU BEACH
7.5-MINUTE QUADRANGLE, LOS ANGELES COUNTY, CALIFORNIA, SEISMIC
HAZARD ZONE REPORT 050, 2001, DEPARTMENT OF CONSERVATION Division
of Mines and Geology
