Historical Society learns about the Swell
The Emery County Historical Society met at the San Rafael Museum to learn about the origin of the San Rafael Swell from Mike Ralphs and enjoy the entertainment provided by Val and Bernice Payne.
Vice Chair Lori Ann Larsen wrote in the Historical Society invitation to this meeting, "Eons ago, tremendous geological upheavals formed a giant dome of rock - a "swell" in the earth's surface. This Swell is one of the most ruggedly beautiful pockets of terrain in the world. Our presenter, Mike Ralphs a native of Ferron Utah, will help us discover what makes our area vastly different from other deserts of the Southwest."
Larsen outlined the evenings meeting by first introducing Bernice and Val Payne who were providing the entertainment playing guitars and singing several songs such as "Sentimental Journey" and a few songs written by Val Payne.
Past President Evelyn Huntsman welcomed Mike Ralphs a Rangeland Scientist (retired) and invited him to tell the group about the history of the San Rafael Swell.
"Mike Ralphs was a research scientist with the Agriculture Research Service arm of USDA at the Poisonous Plants Lab in Logan. Mike has an unparalleled knowledge of the poisonous plants we will see from the Desert to the top of the mountain. His areas of research have included the grazing behavior of cattle in respect to poisonous plants, targeted grazing to control poisonous and noxious weeds, herbicide and biological control of poisonous plants, and the environmental influences on toxin concentrations in plants. Mike is a longtime member of the Society for Range Management, and was awarded the "SRM Outstanding Achievement Award for Research" in 2000. Mike now lives at his family ranch in Ferron."
Ralphs began by explaining he considered himself a farm boy whose mother pushed him off to college which opened up a world of opportunities for him to learn many things. Mike had a 35-year career working for the Government looking, working, cataloging and researching the science of plants and soil.
In college, he studied rangeland management. He studied plants and took a geology class. He still remembers the geology class trip to Buckhorn Draw and the study of those rock formations. It was here that he learned when the earth's sediment and rock formations were formed and what they consisted of.
One of the pivotal events in his life that put him in his position as a rangeland scientist was 4H Club while growing up in Ferron. Some of you may remember Bob and Don Swasey it was they who recruited from the local Range Farm a Conservationist for the Forest Service Chuck Bertmeyer to teach a science class. Chuck took the club down to the desert in the springtime and up into the mountains in summer. Then Mike was introduced to a 4H Range Study Project in plant identification. Where Mike and his fellow club members took first place. That was his introduction to range management.
Ralphs program was titled "Natural History of the Colorado Plateau." He said this San Rafael area is unique in that most of the geology is sedentary caused by lakes or salt seas. Mike described briefly the various rock layers from the top of the mountains to the valley floor, and how they were formed. He said the soil we have here is a combination of those rock layers and a direct result of erosion. These soils formed over millions of years and determine where plant communities thrive. He then described the Colorado plateau, which encompasses Western Colorado, North Western New Mexico, Northern Arizona and Eastern Utah.
Ralphs used a large screen image, titled "Generalized Stratigraphic Diagram of Paleozoic and Mesozoic sedimentary rock units exposed in Utah's Plateau Country",,to display the chronological order of rock and sediment layers of the Swell. He described how over the ages the climate of the earth changed dramatically from wet to tropical to dry and back again several times starting about 320 million years ago. When water covering the earth it began to recede to the West. The ancestral Rocky Mountains were lifted up and then eroded away. As this ancient sea receded or went back towards the West the ponds or pools left became salt deposits and gypsum deposits.
Blowing sand dunes formed the sandstone layers. These sandstone layers are some of the earliest formations we have in the San Rafael area. Ralphs went on to explain how each geological layer was formed and the approximate periods of time when they were formed. The coal seams were formed during a tropical period when the vegetation grew in abundance only to be covered over by sand dunes or an ocean of water depositing silt over the vegetation.
Volcanic ash created the reds, browns, tans and purple colored layers of sandstone. This is also the basis for the Petrified Forest and the Painted Desert in Northern Arizona.
During a great dry period of time in the history of the earth some large sized sand dunes formed. There were three major sand seas that were laid down at that time. The first became the Wingate Sandstone that formed the vertical cliffs at the bottom of Buckhorn Draw. Next came the White Sandstone that formed Eagle Canyon and Ghost Rock. Finally the Entrada Sandstone, which is the Red Mesa and is the same formation that is at Goblin Valley. There followed a period of mountain building in the West about 140 million years ago in Western Nevada and Northern Utah forming a large ring of mountains. That laid down the mudstone and shale of the Morrison formation. The dinosaur fossils are found in the Morrison formation. This was a very warm humid time. About that same time the Colorado Plateau was pushed down and a great inland sea formed down to the Gulf of California. Sediment from the West washed into that sea. This was also a time of large coastal tropical vegetation. This tropical vegetation became peat bogs that were later covered with sandstone and became coal seams in Carbon and Emery County. In this great sea the finer particles went further out and the heavier particles were deposited closer to shore. During this time we have the great Mancos shale formed. There were about six or seven lowering and raising of the sea level at that time resulting in shale, sand, gravel, shale, sand and gravel. These are the soils that we have here in the mountains.
About 65 million years ago there was another period of mountain building this time in the East. The Rocky Mountains were pushed up, the rims in Northern Arizona; the Uinta Mountains in the North and the Colorado Plateau was not as high as the surrounding mountains. Erosion from these mountains came into this area. These eroded into the sandstones of the Mesa Verde group. Very hard sandstone and we have the vertical cliffs.
Ralphs displayed an artists conception "Geology of the San Rafael" which illustrated how the rock layers were shoved up to become the San Rafael Swell. He pointed out the layers of rock formations and some familiar landmarks such as Window Blind Peak, Joe and his dog, Coal Wash, the San Rafael Reef and Sinbad Country.
The study and classification of Utah soils and plants has been Ralphs life's work. He explained the earths soil texture is made up of six types. He listed them as stony, gravel, sand, silt, clay and loam (organic matter) and the conditions that limit plant growth are Saline soil, Sodic soil, rocks and gravel or shallow soil.
"An Ecological Site (NRCS) is a specific combination of soil and precipitation that produces a specific assemblage of plant species forming distinctive plant community."
Using a chart titled "Vegetation Type/Precipitation Zone" he illustrated where various plant communities can be found. The Salt Desert Shrub can be found between 4000 and 5800 feet in the Desert and receives about 8 inches of precipitation. Sage Brush 4500 to 6000 feet in Semi Desert with 9-12 inches of precipitation. Juniper and Pinyon 5000 to 8000 feet in the Upland with 13 to 16 inches of precipitation. Mountain Brush 5500 to 8000 feet on the Mountain with 17 to 22 inches of precipitation. Aspen 7000 to 9000 feet on the High Mountain with 23 to 30 inches of precipitation. Spruce and Fir 7500 to 11000 feet Sub Alpine with 31 to 40 inches of precipitation. Alpine is above 11000 feet.
About 23 million years ago the Colorado Plateau began a gradual rise and tilting towards the South. There was a local up lift at that time creating the San Rafael Swell, the Water Pocket Hole, Capitol Reef, Grand Staircase, Kiabab Plateau, and the Colorado National Monument. These are local areas that were raised up by natural geological forces.
Five million years ago the Colorado River broke through to the Pacific Ocean and started massive erosion. If you look at the elevation on the top of the Wasatch Plateau in the West about 11,000 feet to Moab at the bottom about 4000 feet you have 7000 feet of sediment that has been eroded away in a short period of time leaving canyons and plateaus. This erosion formed the canyons and plateaus that make the fantastic scenes we have in this area.
The San Rafael Swell was a geological up lifted dome that was eroded away exposing the different rock formations that we have in this area. There are 37 different layers of rock from the top of the Swell to the top of the mountains that have been eroded down. There is a tremendous variation in these layers of rock. Here in the valley we have Mancos Shale, which is a clay salty soil from the salty sea. On the benches we have sandstone. In the hills we have sandstone mixing with the clays. The clay loam and sandstone loam are some of the most productive soils in Utah if we only had more water to use.
Ralphs displayed several photos of the mountains, canyons and Buckhorn Draw.
At the conclusion Mike explained his plant display on five large tables filled with various plant types and these were identified as follows: salt desert shrub, desert grassland, sage brush/mountain brush, aspen/tall forb and poisonous plants.