Saturday, December 7, 2013

Cripple Creek's District Museum Mineral Collection



Each month, for the past several years, I go twice  a month with two other scientists (Bob Carnein and John Rakowski) to catalog, photograph, and record detailed information on each specimen we work with. We donate our time to this important project. The Cripple Creek & Victor Gold Mining Company provided the funding for the archival materials that includes special paint and ink pens for catalog numbers, an ultrasonic cleaner, and other miscellaneous materials for the project. In addition to standard photographs of the specimens we work with, microphotographs are taken of certain specimens.I have a few microphotographs of selected specimens I would like to share with you.


Sylvanite crystals in quartz.  Sylvanite is a gold
telluride mineral. Photo © by S. W. Veatch
Calavarite gold telluride mineral specimen no. 196
Photo © by S. W. Veatch
Sylvanite crystal. Specimen no. 196.
Photo © by S. W. Veatch

Sylvanite crystal..  Specimen no 229.
Photo © by S. W. Veatch

Large gold blister from roasted gold sample.
Specimen no. 245. Photo © by S. W. Veatch
Roasted gold specimen no. 246.
Photo © by S. W. Veatch
Roasted gold specimen no. 248.
S. W. Veatch photograph




Another view of specimen 248 showing multiple gold blisters from roasting.
Photo © by S. W. Veatch


Cripple Creek gold ore sliced by diamond rock saw.
Gold and fluorite is present.
Photo © by S. W. Veatch


Calavarite specimen no. 81
Photo © by S. W. Veatch


Group of calavarite gold telluride specimens
Photo © by S. W. Veatch


Krennerite (?) gold telluride specimen no. 129
Photo © by S. W. Veatch

Krennerite (?) gold telluride specimen.
Photo by S. Veatch


Twin crystal of sylvanite. Specimen no. 146.Photo © by S. W. Veatch






Sunday, July 28, 2013

Remarkable Trace Fossil Found Near Woodland Park May Hold Clues to an Ancient Sandstone

By Steven Wade Veatch and Zachary Sepulveda

Winding into the mountains, U.S. highway 24 closely follows the Ute Pass fault, a major fault that separates the Rampart Range from the Pikes Peak massif and the rest of the Front Range. Starting southeast of Cheyenne Mountain, the Ute Pass fault can be traced for about 60 miles, and heads north along state highway 67 beyond Woodland Park. The fault zone is relatively wide and filled with broken and fractured rocks that create the course of Fountain Creek in Ute Pass.
There are at least three resistant ridges made up of sandstone exposed along Ute Pass and in the Woodland Park area. These can be thought of as “fault slices” of a sandstone rock unit “jammed” in Pikes Peak Granite during past movements of the Ute Pass fault. The sandstone rocks are called “injectites” by a number of geologists to describe this remarkable formation. Generally, the color of the injectites is reddish or maroon, but some of the weathered injectites have a buff discoloration on weathered surfaces that is related to the iron oxide cement present in the sandstone.

Today the injectites remain a source of much scientific debate. This was thought to be a sandstone unit called the Sawatch Sandstone that was deposited during the Paleozoic Era in the Cambrian Period—when there was an explosion of multicellular life. Geologists give names to units of rock that were formed generally in the same way at the same time so they can talk about them and map them. Upon closer examination, it is clear this is probably not Sawatch Sandstone. During a recent field trip attended by  seven geologists studying these features in Woodland Park, the scientists began to consider this sandstone was perhaps pre-Cambrian, formed at a time before there was multicellular life on Earth. During the intense and concentrated discussion during this field trip, the scientists considered it a distinct possibility this sandstone was laid down before larger life forms were present; Steve Spence, a geology student at Pikes Peak Community College, climbed a steep slope of this enigmatic sandstone while the geologists were fervently debating.  He came back down with an object he had never seen before and brought it to one of the authors (Veatch) and said, “What is this unusual looking thing?”

Steve Spence, a Pikes Peak Community College Student
with the trace fossil he found. Photo © by S.W. Veatch
Veatch knew exactly what it was—it was a trace fossil of a larger, multicellular creature that once crawled its way through the wet and moist sand millions of years ago. This large trace fossil put the primordial sandstone back in the Paleozoic when there were large, multicellular organisms.


The tube-like structure or the trace fossil was formed by the creature crawling through this ancient
sand and can be clearly seen from this side view. Steven Spence specimen. Photo © S. W. Veatch.

Trace fossils, also known as ichnofossils, are a very important kind of fossil, they record behavior exhibited by prehistoric creatures. They are formed by animals performing actions, rather than animals dying and being preserved in sediment. For instance, a trace fossil might be formed by a worm burrowing its way through the sand, leaving a trail that gets preserved for all of eternity; or a dinosaur traveling to its nesting site and leaving a trail of footprints in deep mud. The term trace fossil may also include other things like remnants organisms left behind, for example, egg shells or coprolites (scat or droppings). Trace fossils leave us with indirect evidence of how past animals lived their lives and how they may have behaved.

Footprint fossils can give us insight not only into the behavior of prehistoric animals, but also into their physical attributes. By looking at footprints we can determine the size, speed, and weight of the animal creating the print. Trace fossils are a valuable source of information on prehistoric animals' behavior and biology.

This is a good example of how science works, and how something can change like the name and age of a sandstone unit. Geologists for decades thought it was the Sawatch Sandstone, and now geologists do not know what the name of the sandstone is or the age of it. Now science has a trace fossil from Woodland Park to add to the understanding of this puzzling sandstone. Scientists will soon probe the mysteries of this ancient sandstone embedded in Pikes Peak Granite and hopefully assign a name and age to it.

About the authors:

Steven Veatch is from a descendant from Cripple Creek miners who mined in the Cripple Creek and Victor Mining District from 1892 to the late 1930s. He teaches the Pikes Peak Pebble Pups to become responsible rock hounds, writers, poets, and scientists. 











Zachary Sepulveda attends Palmer Ridge High School in Monument, Colorado. He is from Southern California, and has always been interested in geology, paleontology and biology. He is looking forward to making a meaningful contribution to the field of science.  His other interests include creative writing and drawing. Some of his poetry and drawings have been published in magazines such as Deposits and in local newspapers. Zachary is a member of the Colorado Springs Mineralogical Society (CSMS) and participates actively in the Pebble Pup/Junior program. He is also a member of the Colorado Scientific Society. 

Monday, March 25, 2013

Dr. John Allen Veatch: A Wayfaring Pioneer in Science and Politics

One hot summer day I was leading a field trip to a site not far from the Colorado School of Mines in Golden, Colorado. As the Colorado sun climbed to its meridian in a blue sky, we explored the local areas where paleontology presented itself in a profusion of mystery and wonder. The most interesting sites to me were narrow and deep slot ravines, cut from clay mining decades ago that now exposed fossil dinosaur tracks, fossil foliage, and a prehistoric rainstorm—where individual rain drops were preserved in mud that had turned, over time, into a layer of sedimentary rock. By the time I arrived with my field party to the mined out slot ravines, the sun was shining directly into them, making the temperature in the ravines seem like the heat of an assayer’s oven.

By the afternoon, we needed a place to cool off from a long day in the summer heat, so I took my group to the Colorado School of Mines Geology Museum. Once we went inside, we were greeted with welcomed cool air flowing from air conditioning vents. In this excellent museum, I showed my field party—a group of people of mixed ages and backgrounds—the section where Colorado gold ore and gold nuggets glittered in the light. Everyone’s eyes were wide, and I could see the sparkling gold reflected in their eyes. A number of jaws silently dropped. All of these gold specimens were from historic Colorado mining sites. Soon, I lost the group as they spread out to look at the fabulous Colorado crystals, rocks, and fossils on display.

I knew on the lower level in the museum the location of an uncommon mineral with an unusual name: veatchite, a strontium borate. I saw this mineral in the museum’s case on a previous trip. After a good hour had passed I went back upstairs and herded my entire group to the lower level of the museum, where I showed everyone that specimen of veatchite in the mineral cabinet.  I wished I could tell them I discovered it, but I had not. This specimen was named after one of my ancestors.  Even though I can’t claim to be its namesake, veatchite and especially the man it was named for had an impact on my life. Is it possible that the passions of your ancestors, especially if they are on both sides of your family, can become your passions?

Image of Veatchite at the Colorado School of Mines Musuem.
© by Steven Wade Veatch
John Allen Veatch was a surgeon, surveyor, and scientist. He was born March 5, 1808, the first of eight children in a Kentucky frontier family. John Veatch’s mother died when he was fourteen. This was a very difficult time for his family. Money was scarce. The Veatch family decided to move to Spencer County, Indiana to start a new life. Another part of the Kentucky Veatch family—attracted by good farmland—moved from Kentucky to northeast Missouri. I am a direct descendent of the Missouri group.
Dr. J. A. Veatch, courtesy photo.

 At the age of nineteen, John Veatch knew that he had to make his own way in the world and look for fresh opportunities. He returned to Kentucky where he started his studies of medicine under a practicing physician, Dr. John Work in Louisville and soon became part of his practice. I noticed in those days it did not take as long to become a medical doctor as it does today.

John Veatch had a restless side to him, and after he had learned as much as he wanted to about the medical profession, he decided to leave Kentucky in 1829. He moved to Louisiana on the Pearl River near Covington and landed a job teaching school. He married Charlotte Edwards in 1831 and had two children:  Andrew Allen Veatch was born in 1832 in Covington and a year later Samuel Houston Veatch was also born in Covington. Samuel Houston Veatch was named after the great Texas General Sam Houston. Charlotte Veatch was so impressed with his "manners and distinguished presence” that she decided that her newborn child would be named Samuel Houston.

In 1834, Dr. Veatch moved to Texas with his family. While in Texas he bought land in Hardin, Trinity, and Jefferson counties. He later obtained additional land in the Zaval Land Grant from the Mexican government. This land would become, fifty years later, sites (Sour Lake and Spindletop) of significant oil discoveries and was some of the most valuable land in Texas. Although he no longer owned all of his holdings in the original Zaval Land Grant at his death, his grandson inherited what was left, 284 acres of oil land in the central part of the Sour Lake District.

The Texas Handbook describes Dr. Veatch as a giant man, standing 6' 4" tall and weighing over 200 pounds. His complexion was fair; he had blue eyes and auburn hair. Is it too much of a stretch to think some of those traits still exist in the Veatch bloodline? After all, I’m 6’ 2” and mild tempered. And, more to the point, I’m also a geologist. I like to think Dr. Veatch would have been proud of me and interested in my geological studies.

Dr. Veatch, during this time, wore more clothing than we do. Because there was no sunscreen, he wore shirts with high necks and long sleeves and long trousers during his field work. He also wore a wide-brimmed hat to have added protection from the sun. Since zippers and snaps had not been invented yet, he relied on buttons, hooks, and eyes for closure. He was characterized as a strong Democrat and was skilled in making friends. The Democrats at this time in history were the party of tradition—the successors of the Jeffersonian agrarians who looked back to the past and were suspicious of banks and corporations. Democrats had a strong commitment to states' rights, a limited federal government, and a continued agrarian ideal. The Democrats (during this time period) were composed of northern craftsman who felt vulnerable to the expansion of industry, farmers who were unhappy with tariffs, immigrants who wanted to maintain their own traditions, southerners who believed in the right to own slaves, and westerners who were in favor of land acquisition by any means, including war.

Dr. Veatch was a capable man and had many intellectual interests. Books became his college. He began to study botany and mineralogy while in Texas. Dr. Veatch was an emissary of science and medicine with wide sympathies, probity, and a strong sense of purpose. He was involved in the political movement seeking the independence of Texas. He was elected as a delegate from Bevil’s settlement (a pre-republic community of settlers between the Neches and Sabine rivers) to the Consultation of 1835, a crowded and raucous assembly that met to consider independent rule for Texas and even armed rebellion to achieve it.  Samuel Houston attended this consultation. Did my ancestor pound his fists on the table like some of the others at the meeting, demanding to be heard? Or did he merely stand on the sidelines, offering considered commentary later in the quiet of a side room conversation? Maybe he gestured and waited to be recognized, making the right point at just the right moment, helping Texas seal it history, if only for a few remembered years?

I’ve given my fair share of speeches in my own career as a geologist but, somehow what I learned about Dr. Veatch feels more impressive. He must have been considered an activist in his times. He even joined the militia during the battles for the independence of Texas. Surely he influenced others with his opinions.  For my part, I prefer exploring the landscape and playing a guitar in old mining camps. To each his own.

The following year (1836), the Texas Declaration of Independence was signed by Samuel Houston and the Battle of the Alamo occurred, where defenders, with infinite courage, held out for 13 days against General Antonio López de Santa Anna's army. The rallying cries “Remember the Alamo!" filled the ranks of the Texan Army led by General Sam Houston. On April 21, his militia attacked the Mexican army at the Battle of San Jacinto, where General Santa Anna was defeated and captured. The independence of Texas was now certain.

The Texas landscape is seemingly endless, like eternity. In the 1840s Dr. Veatch practiced medicine in the new settlement of Town Bluff, Texas. Summer in the area was beautiful: the sun’s light nurtured a landscape dotted with wild flowers that filled the mind with the music of nature. At sundown, the Texas bluebonnets and crimson clover blaze in the golden sunlight of evening while coyotes carefully stalk their prey.

The peaceful beauty did not last long—tragedy struck with the untimely death of Dr. Veatch’s wife Charlotte in 1844. Then the tensions between the United States and Mexico intensified and ultimately reached a breaking point: Between 1846 and 1848, the United States and Mexico went to war. In the war with Mexico, Dr. Veatch served as first lieutenant in Mirabeau B. Lamar’s Independent Volunteer Company during 1846-47. He was the surgeon for this military unit. He also raised a company of men in 1847 that included his two sons, Andrew Allen Veatch and Samuel Houston Veatch. Samuel Houston Veatch was only 14 when he served in his father’s company in the War with Mexico. Later Dr. Veatch served as a Captain in the Texas Mounted Volunteers, who defended the Texas frontier from 1847-1848. The Treaty of Guadalupe Hidalgo, signed on February 2, 1848, ended the war between the United States and Mexico. By the end of the war, Mexico lost nearly half of its territory—the American Southwest from Texas to California.

By 1850, Veatch had moved to San Antonio and continued amassing widespread landholdings in Texas. Dr. Veatch married Ann M. Bradley while living in San Antonio. She had five children from her former marriage—all born in Alabama. Restless for adventure, Dr. Veatch gathered his reins and rode for California where many men were still searching for a golden bonanza. Following a crumbling marriage, Dr. Veatch and Ann divorced while he was in California. His sons Andrew and Samuel came with him to California and kept busy while they panned gold in the gravel bars of streams and rivers.  California continued to experience a large number of people coming into the state looking for gold deposits. It was during Dr. Veatch’s explorations in California that he discovered large deposits of borax (borate related minerals or chemical compounds) in Lake County in 1856.  I can see the site in my mind: the mineral pools, water running over stones, and natural gardens of cactus. Nothing moves other than heat waves, a slight breeze, and a lizard running over a rock slab. As a result of his work there, he published “The Report of Dr. John A. Veatch to the Borax Company of California” in 1857. Subsequently borax became “white gold.” Borax, boric acid, and other compounds of boron were used for medicine, the preservation of food, in glass blowing, and in other industrial applications.

Veatchite, a borate mineral, was discovered in 1938 at the Sterling Borax Mine in Tick Canyon, Los Angeles County, California. Veatchite was named to honor John Veatch. The Sterling Borax Mine is the type locality for veatchite.  To have a new species of mineral or fossil named after a person is a high honor in the world of science. Sometimes, a new mineral, plant, or animal species is named after the scientist who first worked with it, or it can be named after a colleague, a poet, or anyone to honor that person. Generally, the discoverer has the privilege of naming the new species. Since veatchite was not discovered until decades after Dr. Veatch’s investigations, the new mineral was named to honor his scientific work and contributions. Dr. Veatch passed away before the great fortunes were made in the borax industry by 20-mule teams pulling wagons full of borax to processing plants. Dr. Veatch, however, at the time of his death, was far from penniless; he still owned some of the most valuable land in Texas that contained “black gold.”

Dr. Veatch put much in motion when he conducted his studies on the mineral waters in California. While still in California, Dr. Veatch also explored and surveyed Carros Island (off Lower California) in 1858, and then he was the curator of conchology (study of molluscs) at the California Academy of Sciences from 1858 to 1861. He also authored several scientific papers during this period.

In 1862, Dr. Veatch moved yet again.  I think he sought out the wild places where the thunder roared, dust devils whirled, and where he could study the Earth where it revealed itself in the rock record. This time he headed for the gold and silver fields of the Comstock Lode in Nevada—the first major discovery of silver ore in the United States. The Comstock Lode discovery was announced in 1859, starting the “Rush to Washoe” and the establishment of Virginia City almost overnight. Dr. Veatch arrived, after the dust of discovery settled, in 1862—to explore a new mining district. It is hard for any geologist to resist the call of a new discovery of ore and have the chance to study the geological conditions that formed it.

Dr. Veatch practiced medicine and worked in geology in the Comstock Mining District for two years. His son Andrew was superintendent of the reduction works of the Central Mill in the district. Andrew Veatch studied mining and became a prominent mining engineer. I’m not certain how Andrew died, only that he didn’t outlive his father and was sadly buried in 1872, at the young age of 40, in California.  Mentzelia veatchiana or Veatch's blazingstar, when discovered and described by scientists, was named to honor Andrew Veatch.  Samuel Houston Veatch served in the Confederate army and became a Christian minister.

By 1865, Dr. Veatch married a third wife, Samanthe Brisbee. After Dr. Veatch left Virginia City, he worked as a geologist in San Francisco. He maintained an office at 712 Montgomery Street. If his desk was anything like mine, and I like to think it might have been, it surely was cluttered with mineral samples, dusty scales, rock fragments next to a petrographic microscope, and stacks of colorful geologic maps.

Dr. Veatch made an unsuccessful attempt to become state geologist of Oregon in 1868 while still working in San Francisco. He remained in San Francisco until 1869, when his wife Samanthe died.

After his disappointment of not becoming Oregon’s state geologist and the loss of his wife, Dr. Veatch moved to Oregon to join the faculty of Oregon’s first medical school—Willamette University Medical School (in 1913 it became the University of Oregon School of Medicine). He was the professor of chemistry and toxicology. Unfortunately, Dr. Veatch did not hold his new position very long; he died of pneumonia in Portland on April 24, 1870. A new plant species was officially named in 1873 by the California Academy of Science in honor of Dr. Veatch for his pioneering botanical work: Garrya veatchii or Canyon siltassel.  Lotus dendroideus variety veatchii; and Acmispon dendroideus variety veatchii or San Miguel Island deerweed were also named to honor Dr. Veatch.

At the Colorado School of Mines Geology Museum, the group that I led on the field trip that summer day would not know this story of Dr. Veatch by looking through the glass case at veatchite. I did gather the story, and piecing together Dr. Veatch’s life and sharing his name  has helped me to find meaning in my life and helped me to understand why we I enjoy geology so much. In the quest to understand my own life’s path, I believe that the groundwork of my ancestors paved the way for me to do the work I was born to do and that I am now doing today.  

In contrast to Dr. Veatch and countless other wanderers in our nation’s early history—I remain tied to Colorado—just as some of my other ancestors did in the Caribou, Nederland, and Cripple Creek mining camps of Colorado. I made a commitment to Colorado’s mountains, mines, minerals, and fossils to stay in one place so that I could really know the geology of the ground I walk over.

Tuesday, February 26, 2013

Earth Science and Archaeology Haiku Poetry for Fun


 Through many seasons
An ancient volcanic field
Evokes thoughtful pasts 



 
Ancient tree of stone
Herald of another world
Revealing the past



                 
 
 
 
 
Stone Nefertiti
The Queen of Akhenaten
Shifted by a fault






 

 

The sky rejoices
A time for tomorrow’s dreams
Whispering new thoughts








 


A bear carved in rock
Watching the canyon spirits
As a shaman chants




 
 Ancient petroglyph
Art pecked in dark rock varnish
A sacred message




Winter forest realm
Snow spreads its gleaming blanket
A stream turns to ice






The Ice Age icon
A mighty mammoth rules all
Until man arrives













Guest Blogger: Ice Age Poetry by Zach Sepulveda

Twilight of the Mammoths


Perched upon a grassy hill ancient hunters prepare to make a kill…

Blaring trumpets shatter the air
Terrified voices echo despair
Hurtling towards their own demise
A chance at life, their fate denies

The blood of giants spills forth upon the grass
Brought forth by razor-edged volcanic glass
Marching closer to defeat with each fresh laceration
Panicking behemoths flee from inevitable damnation

Perfectly adapted to a dying world
Their fate was sealed when their blanket of ice unfurled
Their fragile world was brought to bear before the fury of the sun
And before they even knew it, their time on earth was done.


Sketch of a Columbian mammoth
© Zachary J. Sepulveda





                                             
 























About the author: Zachary Sepulveda recently moved to the Pikes Peak region from San Diego, CA. He became interested in paleontology by visiting the La Brea Tar Pits in Los Angeles as often as he could. He is a junior member of the Colorado Springs Mineralogical Society and is part of the Pikes Peak Pebble Pups and Earth Science Scholars Program. Zach is 15 years old and is in 10th grade at Palmer Ridge High School in Monument, Colorado.

Note: Zachary will be representing the Colorado Springs Mineralogical Society and the Colorado Scientific Society at the Western Interior Paleontological Society's Founders Symposium: Ice Worlds and Their Fossils. He will present a poster as part of a section on "Bringing the Past to Life (Artist Scientist Panel)." His poster is on poetry and art.



   

Thursday, December 27, 2012

THE RIO GRANDE RIFT

By Steven Wade Veatch

Introduction
A major break in the Earth’s crust – the Rio Grande rift – starts in central Colorado’s Rocky Mountains and runs southward through Colorado and New Mexico into the Mexican State of Chihuahua. The rift is formed where a section of the Earth’s crust arched, weakened, and spread apart due to heat from basaltic magma welling up from the mantle 29 million years ago.

The stretched and brittle crust in the rift thinned and fractured. As tensional forces pulled apart the crust, sections subsided along north-south faults. Some sections dropped more than 8,000 meters. The rifting process resulted in a long rift valley dominated by four connected closed basins in which lava, volcanic ash, and sediments accumulated.

Twenty million years ago, as the North American plate continued to scrape along the east edge of the Pacific plate, crustal stresses resulted in a period of regional uplift, raising much of the southwestern United states to its present elevation. Colorado and adjacent states rose 1,500 meters higher than before the uplift (Chapin and Cather, 1994). During this time of uplift rivers, including the Rio Grande, began flowing into closed basins along the rift. As sand, gravel, and volcanic deposits filled the basins and valleys, the streams ultimately came together forming the Rio Grande River.

Beginning of Rifting
The Rio Grande rift is geologically young, starting 29 million years ago in the Leadville area. Two major episodes of extension have formed the Rio Grande rift. The fist occurred in late Oligocene to early Miocene time beginning 29 million years ago and lasting 10 to 12 million years. Strain rates were less during this early phase of rifting, except where volcanism and high heat flow caused local concentration of extensional strain.

Rifting began to separate the Colorado Plateau from the Great Plains. West of the rift the crust of the Colorado Plateau is approximately 45 kilometers thick; east of the rift the crust beneath the Great Plains is 50 kilometers thick; beneath the rift zone the crust is only 35 kilometers thick (Chapin and Cather, 1994).

Faulting began with the onset of rifting, causing earthquakes along certain areas of the rift zone. Several of New Mexico’s early pueblos were partially destroyed by earthquakes caused by the Rio Grande rift. Faulting and associated earthquakes continue today as the Rio Grande rift continues to widen.

The second episode of extension, the mid-Miocene to Quaternary phase, began about 17 million years ago and continues today. The most rapid phase of regional extension was during this period, from middle to late Miocene time. Evidence of continuing rifting includes young fault scarps, seismiscity, high heat flow, and ongoing uplift as established by geodetic measurements.

Rift Volcanism
The onset of rifting coincided with a period of intense volcanism associated with the early rift basins - as is common in other rift valleys of the world. As extensional forces continued and the crust beneath the widening rift zone was thinned, magma surged to the surface. Most of the volcanism was concentrated on the western side of the Rio Grande rift, where immense eruptions spewed ash over the region. In some areas magma flowed onto the surface and created vast lava fields. Some lavas flowed quietly from vents, forming broad flows that accumulated in layers to form expansive, gently sloping shield volcanoes. In other areas thick lava flows eventually built up to form major mountains. Huge calderas were created when the volcanoes collapsed into vacated magma chambers beneath the volcanoes. Much of the lava is basaltic, evidence that the faults along the rift reach down to the mantle, the source of most basaltic magma (Lipman and Mehnert, 1975).

Smaller volcanic eruptions, some of them within the last few thousand years, have added cinder cones, flows of dark basalt, squeeze-ups, and lava tunnels to the area. These volcanic episodes may have been witnessed by some of North America’s early human inhabitants – Clovis and Folsom Man. It is thought that early man may have witnessed the eruption that formed the Capulin cinder cone at what is now the Capulin Mountain National Monument in northern New Mexico. Capulin Mountain is near the center of the Raton-Clayton volcanic field, which is related to the Rio Grande rift (Stormer, 1987).

The intense volcanic activity along the Rio Grande rift fractured the nearby rocks and permitted the movement of superheated, mineral-rich solutions that formed hydrothermal deposits. These deposits brought in a later group of human inhabitants – the prospectors and miners. Most of New Mexico’s mining districts with their deposits of gold, silver, lead, copper, zinc, molybdenum, fluorite, and barite are concentrated along this mineralized trend near the edges of the Rio Grande rift.

Basins
The Rio Grande rift first developed as a chain of closed basins or half grabens (trench-like features formed by down-dropped blocks of crustal rocks), which gradually filled with lava, ash flows, and sediments that washed in from nearby mountain ranges. Large amounts of sand, gravel, lava, and volcanic ash fill the rift basins to a depth as great as 7.3 kilometers. Sedimentation began in most rift basins in late Oligocene to early Miocene time; however, the basin fill deposits of middle to late Miocene age are dominant in volume. The sedimentary and volcanic deposits of the Rio Grande rift are collectively known as the Santa Fe Group. The Santa Fe Group includes fine to coarse-grained sandstone interbedded with siltsone, conglomerate, and volcanic material. The sediments are generally soft and easily eroded.

Today, starting near Leadville, Colorado and southward to Soccorro, New Mexico, a distance of 550 kilometers, the north-trending rift consists of a series of four en echelon (staggered) basins that join. These basins range from 80 to 240 kilometers in length and from 5 to 95 kilometers in width. The average basin width is 50 kilometers (Chapin and Cather, 1994).

Satellite Image of northern extension of the Rio Grande Rift starting
 near Leadville, Colorado.Image courtesey of NASA.
From north to south these basins are the Upper Arkansas, San Luis, Española, and Albuquerque Basins. The Upper Arkansas Basin is the least understood of the basins as seismic profiles and deep drill hole studies are not available. Rift sedimentary deposits in the Upper Arkansas Basin are named the Dry Union Formation. The best exposures are in the Salida, Colorado area at the south end of the basin. The Dry Union Formation, 1,500 meters thick, contains vertebrate fossils of very late Miocene age (Halley, 1978).

The San Luis Basin is 75 kilometers wide and 160 kilometers long, with the deepest part of the rift just northwest of the Great Sand Dunes National Monument in south central Colorado. The basin is filled with 6.4 kilometers of sediments, mostly Oligocene in age or younger, from the Sangre de Cristo Mountains. The Alamosa basin is the northern part of the San Luis Basin, and is bordered by the San Juan Mountains to the west and the San Luis Hills to the east. The San Luis Hills are erosional remnants of a once extensive volcanic field.


Satellite image of San Luis Valley. Image courtesy of NASA.

South of the Colorado-New Mexico state line is the Taos Plateau, the southern subdivision of the San Luis Basin. This region of broad plains is underlain by basalt. The mountains and hills on the plateau are volcanic features. The Taos Plateau is trenched by gorges of the Rio Grande. Where the Rio Grande Bridge crosses U.S. 64, the Rio Grande is entrenched 185 meters below the bridge and the gorge is 370 meters wide. The gorge cuts into the Serrvilleta Formation (Pliocene), a sequence of coarse-grained and vuggy basalt flows that erupted as highly fluid pahoehoe lava that traveled many kilometers and formed individual units only a few meters thick.

Satellite image of the Taos Plateau. Note extinct volcanic cinder cones
at lower end of the image.  Image courtesy of NASA.
The Española Basin extends 40 kilometers north to south and 64 kilometers east to west. The western half of the basin is a volcanic field; Tertiary sediments fill the remaining portions. The basin ends near the Cerros del Rio volcanic field to the south. The Española Basin, tilted by faulting, contains the Barrancas or badlands, which are carved on volcanic ash deposited before the Rio Grande became a through-flowing river. This volcanic ash weathers to clay that erodes easily to form the badlands. Deposits of the Barrancas contain fossils of extinct mammal, ancestral horses, deer, camel, and bears that thrived here in the early days of the Rio Grande rift. Hot, mineralized water rises along a fault in the Española Basin and surfaces at the hot springs of Ojo Caliente – a site visited by early Indians.

The Albuquerque Basin is one of the largest and deepest basins of the Rio Grande rift. The width varies from about 20 kilometers in the north to 60 kilometers of sediments in the central region. The deepest part of the basin is filled by 7.3 kilometers of sediments.

South of the Albuquerque Basin the rift branches out and widens into a pattern of tilted ranges and parallel basin that resembles the Basin and Range province. Some researchers consider the rift south of the Albuquerque Basin to be part of the Basin and Range province. Others feel the Rio Grande rift should be distinguished from the adjacent Basin and Range province on the basis of its high heat flow, more frequent Pliocene and Quaternary faulting, deep basins, and late Quaternary volcanism (Chapin and Cather, 1994).

Summary
The Rio Grande Valley is not a usual valley – it was not cut by a river and does not branch upstream, as do most river valleys. The Rio Grande, instead, followed a pre-established and partly filled rift valley. The Rio Grande rift is geologically young and resulted from a process of regional extension and mantle upwelling in Neogene times. The Rio Grande rift continues to widen today, and ongoing geologic activity is evident through high heat flow, hot springs, continued siesmicity, geodetic observations, and some of North America's most recent lava flows.

Acknowledgments
Donald A. Coates provided critical review, which improved this paper.


References Cited:

Chapin, Charles E., and Cather, Steven M., 1994, Tectonic setting of the axial basins of the northern and central Rio Grande rift, Geological Society of America Special Paper 291

Halley, J.W., 1978, Guidebook to Rio Grande rift in New Mexico and Colorado, New Mexico Bureau of Mines and Mineral Resources, Circular 163

Lipman, P.W. and Mehnert, H.H., 1975, Late Cenozoic basaltic volcanism and development of the Rio Grande depression in the southern Rocky Mountains: Geological Society of America, Mem. 14

Stormer, John C. Jr., Capulin Mountain volcano and the Raton-Clayton volcanic field, northeastern New Mexico: Geological Society of America Field Guide – Rocky Mountain Section

Wednesday, December 26, 2012

Cub Creek Rock Art: Dinosaur National Monument

Introduction

Dinosaur National Monument, 210,000 acres in size, spans the border between northwest Colorado and northeast Utah. Within the monument is a thick deposit of Jurassic Age dinosaur bones preserved in the lithified sands of an ancient river. Earl Douglass, a paleontologist working for the Carnegie Museum of Pittsburgh, discovered these fossil bones in a tilted rock layer in 1909. Today, paleontologists have chipped away at this rock layer to reveal an incredible array of dinosaur bones. This remarkable tilted rock forms one entire wall of the Quarry Visitor Center, allowing the public to see the bones preserved in their natural state.
 
Long after the dinosaurs that roamed what is now the monument vanished, prehistoric people of the area created designs on rock. Throughout this area “rock art” can be seen on many canyon walls as petroglyphs (drawings pecked or carved on a rock surface). Pictographs (drawings painted with natural pigments on a rock surface) are rare in the park. Within a few miles of the Quarry Visitor Center are several remarkable rock art sites along Cub Creek.
 
The Fremont Culture
The Fremont people created the rock art in the Dinosaur National Monument over 1,000 years ago. These people, named after the Fremont River in south-central Utah, were in the area as early as 200 AD and settled in small villages around 400 AD (Cassells, 1990). Fremont cultural artifacts are found throughout much of the eastern Great Basin Desert, the upper Colorado River and Green River drainage (Hagood and West, 1992).
 
Unlike their southern neighbors, the Anasazi, the Fremont people did not build large cliff dwellings. Instead, the Fremont —living in small bands—made temporary dwellings above and below the ground. Along Cub Creek, in what is now Dinosaur National Monument, the Fremont people lived in small villages of pit houses—shallow circular pits, dug into the ground and covered with mud, branches, and animal hides stretched over a simple framework of poles. They also lived in rock overhangs, shallow caves, and other natural rock shelters.
 
The Fremont hunted bighorn sheep, mule deer, bison, and smaller animals to supplement the corn, beans, and squash they grew. They also gathered grass seeds, piñon nuts, bulbs, and cactus fruits. Tree-ring and radiocarbon techniques have been used to date some Cub Creek sites at around 650 AD (Cole, 1995). Other sites may be older.
 
The Fremont Culture ended sometime around 1300 AD, perhaps after severe droughts forced them to move, or possible assimilation by the Shoshone who moved into the area from the west and south (Hagood and West, 1992). In fact, the Fremont may never have left and simply evolved into a new group as their lifestyle changed over the centuries.
 
Mummified remains of the Fremont, along with artifacts, were found in willow-lined graves in the park (Untermann and Untermann, 1969). Treasure hunters, at the close of the 19th century, robbed the graves.

Petroglyphs
Because the Fremont Culture developed a lifestyle beyond mere subsistence, they had time to create artwork that survived long after they were gone. Their canvasses were smooth surfaces of near-vertical cliff faces and high canyon walls. The Fremont people in the Cub Creek area commonly used the buff-colored Weber Sandstone, formed by both wind and marine deposition during the Pennsylvanian Period.
 
By chipping or scratching through rock surfaces darkened by desert varnish (a natural deposit of mineral oxides and organic material) with sharp tools, these ancient artists exposed the lighter sandstone beneath, creating drawings of animals, human figures, deities, spirits, and abstract geometric designs.
 
Although many designs are recognizable, their meanings are not. It is unknown if the rock art was religious, ceremonial, a record of everyday life, or an artistic expression of prehistoric artists. Researchers have compared Fremont rock art with the symbols of more recent native cultures, however interpretations still remain elusive.
 
The large panel in figure 1 displays themes common to other Fremont sites also in the area: animals, plants, human figures with triangular bodies wearing necklaces, and
geometric designs such as lines and zigzags (Schaafsma, 1995).  Human-like figures, having horns or antennae coming out their head, are visible in figure 2 and 3.  A large dog appears in the left corner.  Different artists worked large panels such as this one over a number of years.  Figure 4 is a depiction of Kokopelli, the flute player. Cub Creek rock art is distinguished by several large lizard figures, like the one in figure 5.


Figure 1.  Rock art of the Fremont people is found on canyon walls of the park.  This panel, near Cub Creek, includes several anthropomorphs, or human-like figures.  Bighorn sheep, once hunted by the Fremont, are portrayed. A number of geometric signs can be seen.  Corn plants are in the bottom right.  Photo date 2/2001 by S.W. Veatch.

Figure 2. A Fremont artist carved this ancient mural into sandstone over 1,000 years ago. This artwork may be a reflection of the Fremont's religion.  A large dog appers on the left corne of this image. Photo date Feb, 2001, by S.W. Veatch.

Figure 3. Close up of the previous panel showing a spirit being with arms raised and hands open. Photo date Feb, 2001, by S.W. Veatch.

Figure 4. Kokopelli, the flute player of Anasazi mythology, reveals Fremont interaction with native cultures of the Four Corners area. Photo date Feb 2001, by S.W. Veatch.
 
Figure 5. A number of lizard images appear only at this site along Cub Creek. Photo date Feb, 2001, by S.W. Veatch.

Table 1. Classic Vernal Style  (Fremont rock art differs in style, theme, and content throughout the region.  The classic Vernal style dominates the rock art in the Dinosaur National Monument)
 
Anthropormorphs (human-like figures) Large trapezoidal bodies with broad shoulders and stick legs are ornately decorated with horned headdresses, earrings, and necklaces.
  • Some figures hold shields or mystical objects.
  • Most designs are outlines, however some are completely pecked to form solid figures.
 
Zoomorphs (animal-like figures): Bighorn sheep, birds, snakes, lizards, and other animals are easily recognizable.
 
Abstract designs: Concentric circles, spirals, rows of dots, and a variety of lines are common.
 
 
Summary

The rocks tell many stories in this remote and rugged land. Preserved in the sands of an ancient river is a time capsule from the world of dinosaurs —a fossil bone deposit that gives the park its name.
 
The rocks in the park also provide an additional view into the past, giving us a hint of the feelings and notions of the Fremont people. The extraordinary shapes and designs of Fremont rock art, taken out of the cultural context of these prehistoric people, are impossible to interpret with our present knowledge. Even though many symbols are recognizable, the meanings have vanished along with the Fremont people. The story the drawings once told—over 1,000 years ago— is lost with the relentless passage of time and is now a secret held in the rocks.

Acknowledgments
Much of the information presented in this paper was gained from a number of field trips undertaken by the author. A number of new images of rock art were obtained with a recent field trip with the South Suburban Park and Recreation Department of Littleton, Colorado. I thank Dr. William Orr of the University of Oregon and Elizabeth Simmons, Metropolitan State College, Denver, for their advice and critically reviewing this paper.
 
 
References Cited:
 
Cassells, E S., 1990. The Archaeology of Colorado. Johnson Books, Boulder, 325 p.
 
Cole, S. J., 1995. Legacy on Stone: Rock Art of the Colorado Plateau and Four Corners
Books, Boulder. 279 p.

Hagood, Z. and West, L., 1992. Dinosaur: The Story Behind the Scenery. KC Publications, Las Vegas, NV 48 p.
 
Schaafsma, P., 1995. Indian Rock Art of the Southwest. University of New Mexico
Press, Albuqurque, NM 329 p.
 
Untermann, G. E. and Untermann, B.R. , 1969. A Popular Guide to the Geology of Dinosaur National Monument. Dinosaur National Monument Association, Dinosaur National Monument, Utah - Colorado. 126 p.