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UCMP's Spring Break 2015 southern California field trip, page 3

Back in the cars, we continued southwest up Fish Creek Wash. Seth pointed out rocks representing some of the first sediments originating from the ancestral Colorado River. This proved to be a big clue to the origin of the next section we'd be looking at. Farther down the wash we stopped at a cliff composed of dozens of layers of nearly equal thickness. Seth and Cindy left the students to study these rocks while they went off to scout the North Fork of Fish Creek Wash to see if it was passable (it was not). Upon their return, Seth explained that these rock layers were from sands deposited by the young Colorado River far out on the river's shallowly sloping delta at the northern end of the Gulf of California embayment.

At the end the day, we hiked a mile up to the Wind Caves, a sandstone exposure full of caves and holes scoured by wind-borne grit. We explored these and climbed the ridge above the caves to watch the setting sun. Back at camp, Camilla and Lucy prepared a nice dinner of penne pasta.

Left: The groups spread out to look at a new section. Photo by Dave Smith. Top middle: Seth and Cindy listen to the students' theories on the origins of these rocks made up of layers of equal thickness. Photo by Dave Smith. Top right: Another blooming cactus. Photo by Dave Smith. Bottom middle: Exploring Wind Caves. Photo by Dave Smith. Bottom right: Caitlin is revealed through one of the scoured openings in the rock. Photo by Dave Smith.

The extent of the Wind Caves, as seen from the ridge to the north
The Mud Hills and Elephant Knees Buttes at sunset
Top: The full extent of the Wind Caves, as seen from the ridge to the north. Photo by Dave Smith. Bottom: The Mud Hills and Elephant Knees Buttes at sunset, as seen from the same ridge (a portion of the Wind Caves is visible at the lower right). Photo by Camilla Souto.

Friday, March 27
In the morning, we packed up our tents, had a quick breakfast, loaded up the vehicles and left Fish Creek Wash behind, but not before passing new groups of second graders on their way in to Split Mountain. Seth thought that we could squeeze in a visit to a locality at the southern end of the park, but it would take too long to get there via paved roads, so we took a short cut — a dirt track paralleling southeast-trending railroad tracks that would take us down to Interstate 8. It was a very sandy track and we made good time for a while, but maybe 15 miles out, it became too sandy — so sandy that there was a good chance a vehicle could get stuck. We could not afford to have that happen, so we cut our losses and turned around to retrace our route, but not before getting out of the cars to admire the fossil bivalves and gastropods that littered the ground. It was hard to believe but apparently there had once been a large lake here in the not too distant past.

Once back on asphalt, we wasted no more time and took State Route 78 east to the Sonny Bono Salton Sea National Wildlife Refuge along the southeastern shore of the Salton Sea. We took a hike along the Rock Hill Trail and went out to the foul-smelling beach, covered with the calcareous plates of dead barnacles, as well as the bones of birds and fish. The trail led us to the top of a low rhyolite dome where we could get a better sense of the enormity of this highly saline and toxic lake. Back at the visitor center, we took advantage of the refuge's shaded picnic area and had a leisurely lunch. We were serenaded by numerous birds that flocked to the island of greenery surrounding the visitor center.

Top left: After nearly getting stuck in the sand, we notice the fossil bivalves and gastropods that litter the ground. Photo by Dave Smith. Middle: A concentration of fossil gastropods on this now dry Pleistocene lakebed. Photo by Camilla Souto. Top right: Well-preserved fossil bivalves. Photo by Dave Smith. Bottom left: The sign welcoming us to the Sonny Bono Salton Sea National Wildlife Refuge. Photo by Camilla Souto. Bottom right: Examing the bones and barnacles on the shore of the Salton Sea. The hill in the background is the rhyolite core of an ancient volcano. Photo by Dave Smith.

Top left: An unpleasant looking section of Salton Sea shoreline. Photo by Dave Smith. Top middle: Looking out at the lake from the rhyolite hill. Photo by Cindy Looy. Top right: Ash contemplates one of the mud volcanoes. Photo by Dave Smith. Bottom left: A bubbling mud volcano. Photo by Cindy Looy. Bottom middle: A mud flow from one of the mud volcanoes. Photo by Dave Smith.Bottom right: The mud volcanoes are in an empty lot next to a geothermal plant. Photo by Cindy Looy.

From the refuge, we had just a short drive to our next destination: mud volcanoes. These were out in a flat, empty lot adjacent to one of the 11 geothermal plants that exist near the lake. The volcanoes were small — the tallest being maybe seven feet — but they were quite entertaining, what with the hissing of escaping gas and the bubbling and plopping of mud within their craters. Then it was on to the small town of Niland, where we made a brief stop to get water and other supplies. We headed north on State Route 111 to the Salton Sea State Recreation Area to pay one last visit to the lake's barnacle-covered beaches before continuing on to our final destination: Painted Canyon in the hills north of Mecca. The Mecca Hills are interesting geologically because of the folding and faulting caused by activity along the San Andreas Fault.

Top left: Checking out the beach at the Salton Sea State Recreation Area at the lake's north end. Photo by Dave Smith. Top middle: Here the beach is still sandy, but that will soon change. Photo by Dave Smith. Right: Closer to the water, Ash Poust picks up a handful of the calcareous plates of dead barnacles that blanket the beach. Photo by Cindy Looy. Bottom left: A beach composed entirely of dead barnacles, with an occasional fish or bird. Photo by Cindy Looy. Bottom middle: A closer look at the barnacles. Photo by Cindy Looy.

Leaving the vehicles at the Painted Canyon trailhead parking area, Seth led us into the high-walled, but broad, canyon. We did not stay in the main canyon for long — Seth veered off into a side slot canyon that had a series of ladders to be negotiated before one emerged at the top of the ridge. Most of the students continued up the trail, planning to return to the trailhead via the main canyon, but Seth, Cindy, Jeff, and Dave retraced their steps so they could get a jump on choosing a campsite and getting dinner started. Seth assisted Cindy in the creation of a Dutch chili with polenta.

Jeff and Cindy on the trail Our camp in Painted Canyon Late afternoon sun in Painted Canyon
Top left: About to set out on our hike in Painted Canyon. Photo by Dave Smith. Top middle: The trail began in a fairly broad canyon. Photo by Camilla Souto. Top right: We entered a slot canyon where several ladders were encountered. Photo by Cindy Looy. Center left: Looking up from the bottom of the slot canyon. Photo by Cindy Looy. Center middle: Cindy on one of the ladders. Photo by Camilla Souto. Center right: Emerging from the slot canyon, one is rewarded with this view to the south. A bit of the Salton Sea is visible. Photo by Dave Smith. Bottom left: Jeff and Cindy on the trail. Photo by Dave Smith. Bottom middle: Our camp in Painted Canyon. Bottom right: Late afternoon sun on the rocks of Painted Canyon. Photo by Camilla Souto.

Saturday, March 28
On our last morning we had one of our fancier breakfasts. Zixiang cooked bacon and Caitlin used the dinner leftovers to make an egg and chili scramble. We packed up and drove out of the canyon just as the sun cleared the cliffs above us. We had two relatively short geology stops to make before we could head back to the Bay Area. During a stop along Box Canyon Road, some final demonstrations of strike and dip measurements were made for students without a geology background. Farther down the road, Seth pointed out deltaic sands deposited by a river entering a lake.

Top left: Before heading home, we made a couple of stops along Box Canyon Road. At one stop we found these rock layers representing deltaic deposits. Photo by Dave Smith. Top middle: The palo verde were in bloom. This is an unusual tree in that it's trunk and branches photosynthesize, not just its leaves. Photo by Dave Smith. Right: Dori demonstrates how to take a strike and dip with a Brunton compass. Photo by Dave Smith. Bottom left: The group (minus Seth) poses by a Joshua tree. Photo by Cindy Looy. Bottom middle: Reflecting on our trip. Photo by Dave Smith.

To get home, we took Interstate 10 to I-15, State Route 58 through Tehachapi Pass, then I-5 up to Interstate 580 and the Bay Area. We made three major stops on the way: one stop was for Natalia — she wanted to get a good look at a Joshua tree. Another stop was for coffee at a Starbuck's in Bakersfield. The final stop was the most anticipated and enjoyable: dinner at an In-N-Out Burger off I-5's Santa Nella Boulevard exit. We all arrived home quite late, but it was safe to say that a good time was had by all.

Future field trips
Seth was thinking about doing a Great Basin (Nevada and Utah) trip next year, but there were some other options presented, such as the Channel Islands. Cindy has field experience in Italy so she was pushing for that as a destination, but the logistics and expense of such a trip would probably be prohibitive. Wherever the destination, one can count on seeing some spectacular geology and coming away with a greater understanding of the processes responsible for that setting.

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