Rice Canyon Geology

Rice Canyon bisects the Pico anticline, although there are not too many good exposures of bedrock on the trail. The Modelo Formation is the oldest formation and is exposed in the axis of the anticline. It consists of brown shales and gray-yellow concretions of limestone. Like Wiley Canyon, the axis is considerably crumpled. All wells were drilled in the Modelo Formation. The Towsley Formation and the Pico Formation are also exposed in the canyon.

Geologic map from Winterer and Durham (1962). The red dot is the old end of the Rice Canyon trail at the large oak tree. Now the main trail doesn't head up that way but goes straight for a while and then loops to the left back up the mountain.

Tp, Tpc, Tps = Pico Formation (lower Pliocene)
Tt, Ttc = Towsley Formation (lower Pliocene)
Tm = Modelo Formation (upper Miocene)

This interesting exposure is on the east (left) side of the canyon soon after you begin your hike up the Rice/East Canyon road. (photo taken on 11/9/2008)

Here's a photo of the above feature from 1928 taken by Ralph Arnold. From the Ralph Arnold Papers, "Needham Tract", p. 11, Huntington Library. The photo captain said "No. 8: Looking northeast at the contact between the bluish, massive Pico sandy shale (below) and the lighter-colored gravel and coarse sand layers of the Saugus formation (above) at the junction of Rice and East canyons. This photograph shows in general the differences between the Pico and Saugus formations. Photo by Ralph Arnold, Mar. 17, 1928."

Steep beds of the north flank of the Pico Anticline. This is probably the Towsley Formation. (10/26/2008)

As we hike futher into the Rice Canyon we find these are crumpled north flank beds of the Modelo Formation on the side of the trail. (11/9/2008)

This is a high up view of the north flank of the Pico Anticline in Rice Canyon. (10/26/2008)

Nearly horizontal beds at the axis of the anticline. (11/9/2008)

This seep at the axis is just above the level of the creek bed. It is possible that this is the site of an old spring-pole well dug before PCO (later Standard Oil) owned the site. (11/9/2008)

Looking down to the creek from the seep. (11/9/2008)

A closer look at the seep. (11/9/2008)

Here is a view of the south flank of the Pico Anticline where there are many oil seeps. (11/9/2008)

Here is a south flank seep draining down into the creek. (11/9/2008)

Here is another south flank seep. (11/9/2008)

Oily water. (11/9/2008)