Redlands San Timoteo Canyon EarthCache

1. Find soil around ground zero and offer an opinion of the color and texture. What makes the adobe soil here unique?
2. How many steep gorges you can see from ground zero as you look across south towards Moreno Valley? Could you hike them?
3. At this location, where is the area of most erosion and why do you think it is there?
4. Estimate the distance from here to the canyon floor. How long do you think it would take you to hike to the floor of the canyon from here? What equipment would you need?
5. Why do you think some people call San Timoteo Canyon, "The Badlands?"
6. Bring previous logs with you to the site. Why do you agree or disagree with their answers?

Redlands was the shared dream of Frank E. Brown (civil engineer and Yale graduate) and E. G. Judson (New York stock broker). They met in Southern California during the late 1870's. They named their colony, Redlands, for the color of the adobe soil. The two busily laid out a city, brought water from the mountains to the community, introduced the newly discovered Washington navel orange, and recruited settlers.

Ground zero represents high ground on the northern side for you to view 14-mile long San Timoteo Canyon within the National Geological Survey's Sunnymead quadrangle. The geology here is part of the Peninsular Ranges Province and is underlain by Cretaceous basement rocks, which contain a few scattered pendants of Paleozoic metamorphic rocks. This part of the Peninsular Ranges Province is divided into the Perris block, located west of the San Jacinto fault and the San Jacinto Mountains block to the east. The northeast quarter of the quadrangle is crossed diagonally by the San Jacinto fault zone, a seismicly active major fault of the San Andreas fault system. The San Jacinto fault zone consists of a main trace, which forms a relatively continuous, dissected, west-facing, fault scarp about 1,000 feet above the valley floor, in addition to multiple discontinuous breaks. The area north of the San Jacinto fault zone is termed the San Timoteo Badlands (where you are standing and shaded yellow and red on the map image below).

It is formed in a thick section of Pliocene and Pleistocene continental sedimentary rocks, which are informally referred to as the upper part of the San Timoteo beds of Frick (1921) (Morton, 1999). This unit consists chiefly of coarse-grained sandstone, conglomeratic sandstone, and conglomerate. All clasts within these beds were derived from Transverse Ranges basement rocks found north of the quadrangle (where the town of Redlands is today). The San Timoteo beds have been deformed into a broad anticlinal structure produced by the sedimentary beds being compressed as they are translated around a restraining bend in the San Jacinto fault north of the El Casco quadrangle. A curving, diachronous fault produced by this compression is located in the western part of the badlands just east of the San Jacinto fault zone (near the town of Loma Linda). The area west of the San Jacinto fault zone is underlain by plutonic rocks of the Cretaceous-age Peninsular Ranges batholith with a few small included pendants of schist and gneiss of probable Paleozoic age. Most of the plutonic rocks are biotite-hornblende tonalite, but locally include abundant granodiorite. In the northwestern part of the quadrangle is the eastern part of the Box Springs granitic complex, a basin-shaped complex that appears to be the distal part of a diapiric-shaped structure. Most of the alluviated area west of the San Jacinto fault zone consists of Pleistocene age fluvial deposits, which typically have a degraded upper surface that is preserved in some places near the contact with granitic rocks. Holocene age alluvial fans emanate from the San Timoteo Badlands. The canyon (Badlands) ranges in size from one-quarter to one-half mile wide. Slopes vary in size from 2400 feet at the eastern end of Beaumont to 1200 feet at the western end of Loma Linda. Canyons are formed by river erosion like the seasonal creek that flows through San Timoteo Canyon. Cliffs on either side of a canyon are made of harder rock. The area that has been worn away tends to be of a softer rock that can be weathered easily by water and wind.

Take note of the correlation of map units image above. You are standing on special soil. Soil that named a town, "Redlands" and ancient relative to surrounding areas. The majority of the San Timoteo Canyon soil is part of the Pleistocene and Pliocene eras defined by gray, coarse-grained, moderately indurated sandstone and conglomerate. It contains early Pleistocene Irvingtonian I, Shutt Ranch and El Casco local faunas, about 1.8 Million years old. This soil erodes to form the sharp-ridged badlands topography you see across to the south.

Overall, the canyon consists of about 70 percent sandstone and 30 percent conglomerate. The conglomerate is more abundant where you are standing. It includes numerous reddish-brown stratigraphic intervals consisting of oxidized sandstone, which are not paleosols, and reddishbrown clay-rich intervals, which may be paleosols. This soil erodes to form the sharp-ridged badlands topography. In the eastern part of the geological quadrangle, hogbacks on the south side of San Timoteo Canyon are formed. Included within is highly deformed, fault-bounded sandstone, pebbly sandstone, and conglomerate located along the western part of the badlands adjacent to the Claremont Fault.

Fossils have been found within San Timoteo Canyon by soaking the sediment chipped away from canyon walls and then screening the mud through fine mesh. Thousands of pounds of sandstone are dug up with each large fossil to ensure that all of the animal is collected. The La Brea Tar Pits are well known in Southern California, but experts say the fossils found in San Timoteo Canyon are one million years older than anything found in the Tar Pits. The fossils were not found where you are standing. Imagine if you could excavate here, what you may find. The artifacts would be older than La Brea and older than what was found within the canyon below. The artifacts could be more than 2.5 Million years old. You are in deed standing on special soil.

References:
http://www.world66.com/northamerica/unitedstates/california/inlandempire/redlands
http://en.wikipedia.org/wiki/San_Timoteo_Canyon
Albright, Lynn Barry. Biostratigraphy and vertebrate paleontology of the San Timoteo Badlands?
McKinney, John. California's Parks: A Day Hiker's Guide.
Morton, D. M. (1999) Preliminary digital geologic map of the Santa Ana 30' X 60' quadrangle, southern California: U.S. Geological Survey Open-File Report 99-172, 61p., scale, 1:100,000.