Mono Basin and
Ichthyosaur IState Park


June 18 - 20
By Allan Schoenherr

Imagine the confusion!!! The meeting place for this trip, the rest stop on Highway 395, was closed for repairs. Some last minute e-mails succeeded in communicating a change for the Friday morning meeting to the intersection of Highway 395 and the Mammoth Lakes Scenic Loop (The earthquake escape route). An added frustration appeared on Thursday evening when it was discovered that the proposed campsite at Lower Deadman Campground was closed due to flooding. Undaunted, we selected a scenic spot in the forest along the Mammoth Lakes Scenic Loop.
Friday morning: Five cars left from the appointed meeting spot and traveled to the southernmost of the Mono Craters, which are aptly named Inyo Craters, as they lie in Inyo County, just off the Scenic Loop. Participants included Mignon Slentz, Glenn Shaw, George Gilster, Sally Kinsey, Robert Day, and Steve Miller. A short, but semi-steep hike, through a shady Jeffrey Pine forest, brought us to the two craters. These side-by-side craters, were caused by volcanic steam explosions about 600 years ago. What makes these twin craters especially interesting is that they have lakes in the bottom which are entirely different in color. One lake is a murky green and the other is a clear blue. Some references say the cause of the differentt colors is unknown, but a recent scientific paper explains that different chemistry is responsible for the colors. The clear lake has more of a forest margin which adds organic material to the water. Decomposition of the organic material makes the lake slightly acidic which causes precipitation of suspended material so that the water remains relatively clear and blue. The other lake with all its suspended material remains green and cloudy. Experimental addition of sulphuric acid to the cloudy lake caused it to become temporarily clear.
Next stop was Obsidian Dome, a scenic jumble of huge obsidian boulders. A number of these domes, composed of obsidian or pumice, lie along a fault line that runs from Mammoth Mountain to Mono Lake. They are conspicuous from the air, but can be seen from Highway 395. We talked about how obsidian is formed, how to identify the different kinds of pine trees, and we stopped here for lunch.
After lunch, following a quick stop for fuel at the June Lake junction, we headed toward Mono Lake. Just south of Mono Lake there is a conspicuous row of volcanic hills known as Mono Craters. From an age of 10,000 to 2,000 years, these craters continued to erupt until about 600 years ago, which makes this arc of 27 craters the youngest mountain range in the United States. One of the northernmost of these craters is Panum Crater. This crater originally was formed by a gas explosion similarly to the Inyo Craters. However, a second eruption produced a large plug of picturesque obsidian in its center. A steep trail leads up to the plug and everyone in our group made it to the top in order to marvel at the spectacular views of the eastern Sierra Nevada, Mono Craters, and Mono Lake.
Next, we stopped at South Tufa on the shoreline of Mono Lake. Mono Lake is a very concentrated saline lake, a consequence of its great age. The lake may have continuously held water for 2 million years, during which time the evaporation of water has left behind an accumulation of dissolved minerals. The picturesque tufa towers are pinnacles of calcium carbonate which were produced by precipitation under water, a process caused by the bubbling of fresh water through the brine. In 1942 the Los Angeles Department of Water and Power began diverting the fresh water streams that fed Mono Lake southward into the LA Aqueduct. Ultimately, with reduced fresh water input, the lake level was lowered by 40 feet, exposing the tufa towers. The area is now classified as a National Scenic Area. During the period of lowest water an island in the center of the lake became connected to the shoreline. For thousands of years, this island has been one of the most important nesting areas for the California Gull. The lowered water level enabled coyotes to travel out to the island and prey upon the nests of the gulls, seriously threatening survival of the species. Today, in an attempt to bring back the lake level to a more normal height, the Department of Water and Power is required to allow a portion of the fresh water to continuously flow into the lake. The simple ecosystem of Mono Lake depends on high concentrations of Cyanobacteria (Blue-green Algae) that thrive in the hypersaline water. Brine Shrimp and Brine Flies eat the algae. The Brine Flies, conspicuous at the water’s edge, lay their eggs along the shoreline. The birds eat the Brine Shrimp and the Brine Flies. Indians formerly ate all of them, including a food made from the Brine Fly eggs. During our visit, the wind was blowing the Brine Flies off the shore onto the water. We were able to watch the gulls, positioned into the wind, floating on the water while they gorged on the flies.
Friday night we set up camp in a grove of Pinyon and Jeffrey Pines on the south side of Mono Lake. We had a spectacular view of the lake as we enjoyed our traditional potluck. We were joined at that time by Leonard and Rebecca Friedman, and their daughter Hannah, who entertained us with word games in the evening as we sat around the campfire.
Saturday’s activities began at the Mono Lake Visitor Center. Then our group of six autos traveled by dirt road up scenic Cottonwood Canyon to the famous ghost town of Bodie. We spent the morning looking around and photographing the interesting restored and preserved buildings. We ate lunch in a day-use site just east of the town. After lunch, we ventured into unknown territory as we followed a dirt road eastward along Bodie Creek toward the ghost town of Aurora and ultimately Hawthorne, Nevada. We were warned the road would be rough, and it was, but it did not phase the Desert Explorers. First stop was an old stamp mill, but we stopped many times as we enjoyed the canyon scenery and the wildflowers. We stopped for gas in Hawthorne and then moved on to the scenic campground amongst the Pinyon Pines at Berlin-Ichthyosaur State Park. Park personnel were waiting for us with descriptive pamphlets and signs directing us to our reserved campsite. That evening we enjoyed another fine meal, a campfire, and group comraderie.
The next morning we convinced the park ranger to do an early tour of the Ichthyosaur site (the Nevada state fossil) and were treated to an enthusiastic explanation of the significance of this spectacular fossil site. These ancient extinct reptiles represented a life style now demonstrated by marine mammals such as dolphins and whales. In fact the Ichthyosaurs at this site were among the largest of their kind. Imagine 60-foot-long reptiles with mouths like crocodiles, living a lifestyle like a modern day Moby Dick (Sperm Whale). We had a group photo taken in front of a life-sized mural of an ichthyosaur. Not realizing we had an early tour, Bob and Sally already had left for home and unfortunately missed the photo. After our tour most of us wandered around the restored ghost town of Berlin before traveling for home. Thereafter, some folks went on to other destinations including the nearby ghost town of Ione. Tours of the Berlin mine itself had been temporarily discontinued because of budget cutbacks.