PUEBLO ROCKHOUNDS                                                     May 2008

May2008 Presidents’ Message

Where has the year gone?  2008 is almost half over!  This month will be our last official meeting until September.  We hope to see you at this final formal get together until after the summer! 

Last month we had guest speakers Bill and Beth Sagstetter share their book “Mining Camps Speak” and their knowledge on the topic.  It was very interesting.  We hope you have had a chance to go to the web site and view the goings on if you missed it (or look for the back of your head if you were there!).  J  Once again our thanks to the Sagstetters and to Einar for making their program a reality for our club.

At our meeting this month, Dr. Bob Carnein will present a program on the “Geology and Origin of the Franklin/Ogdensburg Zinc Mines”.  This will round out our trifecta of mining programs!  (Or so we thought until we actually looked up the meaning of the word trifecta!  Oh, well, it sounded good!)  No matter what word we use, the programs that we have had planned for these past three months have been tremendous!  We hope you don’t forgo coming to the meeting on the 15^th!  (Julie will be a little late as three of her students are being honored for their poetry writing at the Rawlings library at 7:00 the same night.  Tom will hold down the fort until she returns!)

Hope to see you all this Thursday!

Tom and Julie Frink

  Co-Presidents

____________________________________________

This Month’s Program:

Club Members should RESERVE THE THIRD THURSDAY of each month except June through August for an informative and fun evening with the Pueblo Rockhounds.

This month’s program will be by Dr. Bob Carnein. He will present a program about the Franklin/Ogdensburg Zinc Mines.  This world famous mining area has produced many fabulous fluorescent minerals.  Don’t miss this meeting on Thursday May 15^th.

Our next meeting will be on September 18, 2008.  Enjoy your summer and the many field trip possibilities that are scheduled.

________________________________________________________________________

TREATS – Yum – Yum!!

According to the records, the following persons have volunteered for the April meeting: Don & Bev Keith & Richard & Kathy Koen (Drinks)

No meetings until September, Rockhounds Picnic? ________________________________________________________________________

GEM, MINERAL, AND FOSSIL SPECIMENS!!!

Bring your Fluorescent minerals from the Franklin, New Jersey Area and share them with the club on Thursday.  Also, bring any other interesting samples (Baculite Mesa Field Trip?) or other works, they are always welcome!

________________________________________________________________________

BIRTHDAYS 

________________________________________________________________________

Wedding Anniversaries

________________________________________________________________________

________________________________________________________________________

SHOWS & EVENTS

________________________________________________________________________

WHAT IS DICHROIC GLASS? by Steve Weinberger

Most of us have seen the fabulous jewelry objects made with dichroic glass, and some of us have worked with it.  Like many of the synthetic materials we’ve used in lapidary and jewelry, dichroic (Dye-Crolck) glass was developed for another V use other than jewelry.  The word dichroic comes from two Greek roots – “di” for two and “chroma” for color.  Thus, dichroic literally means “two colored”.

First developed by NASA in the 1950’s for use in satellite mirrors and optical filters, the glass is made by evaporated metallic oxide onto glass in a vacuum chamber. That golden sheen you see on the face mask of our astronauts as they do their space walks is really a dichroic coating meant to protect against the glare of natural and obviously unfiltered sunlight.

The various ultra-thin coatings are metallic oxides.  Gold, silver, titanium, chromium, aluminum, zirconium, magnesium, and silicon are the metals used.  As the oxides are exposed to high temperatures and a high voltage electron beam, they are vaporized and deposited onto the surface of the glass.  Each metal oxide produces different colors on the glass.  Often several different oxides are deposited on the glass to produce varying effects.  These thin layers have a total thickness of three to five mil/ionths of an inch!

The dichroic coating itself has no color.  The colors are created by light striking the coatings on the glass.  Each piece has three colors associated with it – a reflected color, a transmitted color and a third reflective color that can be viewed at a 45 degree angle. 

This is what causes the glass to change color when you turn the piece.

The resulting plates of glass can then be fused with other glass in a kiln.  Certain wavelengths of light will either pass through or be reflected, causing an array of color to be visible.  Colors vary, even with using glass from the same larger piece because of variations in the firing process and thus, each piece of fused dichroic glass becomes unique.

Although dichro is an expensive material due to the high cost of manufacturing (a 4”x 4” clear piece can cost about $14 while some patterned or textured sheets of the same size can run as much as $65each), the resulting jewelry can be very striking.  Dichro is available from many sources.

References: Becky Edmundson, instructor at Wildacres Wikipedia<en.wikipedia.org/wiki/Dichroic_gjass>Artisan Dichroic<www.artisandic hroic.com >  Trezora Glass www.trezora.com  >

From The Glacial Drifter, April 2008

________________________________________________________________________

Exploring Colorado Springs Geology:

Popes Bluff and Ute Valley Park by Mike Nelson, CSMS

The Colorado Springs area is home to some of the world’s most fascinating geological wonders ranging from Pikes Peak (igneous rocks, mostly granitic, emplaced about 1.1 billion years ago) to majestic ridge- and spire-forming sandstones of late Paleozic age (~325-290 million years ago) cropping out in Garden of the Gods Park.  Unlike many well known localities, the areas of geological interest in and near Colorado Springs are readily accessible to most people.  The rocks of majestic Pikes Peak may be observed along the Pikes Peak Toll Highway, US Hwy 24 to Woodland Park, as well as along numerous secondary roads such as the Old Stagecoach and Gold Camp roads leading to Cripple Creek. Garden of the Gods is a Colorado Springs City Park readily accessed by several roads and trails.

With such world-famous sites available to all, we often overlook interesting localities in our backyard where both the casual observer and the dedicated hiker can get up close and personal with the rocks (it’s tough to get personal with the Peak).  Virtually every Colorado Springs driver on I-25 has noticed such features as Pulpit Rock and Austin Bluffs, associated with the north-south trending highland of the Palmer Divide.  Those traveling Centennial Blvd. and/or Vindicator Drive are aware of the massive bluffs and up-turned rocks of Popes Bluff.  But, how many people have actually stopped to examine some of these fascinating exposures.

Popes Bluff Area (PBA), including the adjacent highlands and hills of the Ute Valley Park and the bluffs associated with Popes Valley Creek (along Popes Valley Dr.), is generally bounded by Centennial Blvd. on the west, Garden of the Gods Road on the south, Rockrimmon Blvd. and Vindicator Drive on the north, and I-25 on the east.  The bluffs and valley walls present numerous well exposed outcrops of the Upper Cretaceous Laramie Formation including abandoned coal mines, rock quarries, upturned hogbacks, and a large open space perfect for hiking, bird watching, and plant identification.  Jon Thorson completed a geologic map of the Pikeview Quandrangle (Thorson and others. 2001), and readers should consult that publication for greater details.

Rocks of the Laramie Formation, so well exposed in the PBA, represent the final regression or the vast Western Interior Seaway (WIS) that flooded what is now Colorado during much of the Cretaceous Period (~144 to ~65 million years ago).  The oldest of the local Cretaceous rocks, and ones representing the transgression of the WIS are the complex of near shore marine, beach, deltaic, and estuarine sandstones (mostly) of the “Dakota Hogback”, a prominent topographic feature along much of the eastern flank of the Colorado Front Range.  The Granerous Shale, overlying the Dakota, is a dark colored shale representing deepening waters (transgressing seas) and deposits of offshore mud.  As the seaway continued to deepen, the limestones and chalks of the Benton and Niobrara formations were deposited.  These limey muds were followed by deposition of thousands of feet of marine muds laid down many miles from shoreline.  This mud became known as the Pierre Shale and is present under nearly all of eastern Colorado (Matthews, 2003).  Most of these Cretaceous rocks described above are well exposed in or near the Garden of the Gods Park and Red Rock Canyon Park.  The Pierre Shale can readily be observed in road cuts along Uintah Street leading west from I-25.

Perhaps 70 million years ago the early Rocky Mountains began to appear, and the WIS started its retreat from Colorado.  The beach sands or the regressive seas are known as the Fox Hills Sandstone and are not well exposed near the Bluffs; however, there is an exposure near Centennial Blvd. about a mile north of its intersection with Vindicator Drive.  Overlying the Fox Hills is the Laramie Formation, described below, while the end of the Cretaceous, and the beginning of the Tertiary (K-T), is marked by deposition of coarse sediments shed off the rising Rocky Mountain Front, the Dawson Formation.  These rocks may be observed east of I-25 at Palmer Drive.

The Laramie Formation (description excerpted from Thorson and others, 2001) is a complex of rocks representing rivers, beaches, channel fillings, coal swamps, flooded plains, lagoons, and estuaries-the sort of environments present along a regressing sea.  At the entrance of Popes Valley (off Rusina Road), the road cut exposes a nice section of brownish-gray sandy shale and an organic-rich, dark-brown coaly shale; thinner beds of fine grained sandstones also are present .  This sequence was probably deposited between river channels.  Above this section, and well-exposed on the north side of the valley, is a thick, light gray to light orange, cross-bedded sandstone forming the valley rim (and holding up houses) .  This sandstone and its counterparts represent deposition in a river system and can be seen along Popes Bluff (from Centennial Blvd.) and along the highlands and hiking trails within Ute Valley Park.

One of the more fascinating sections of the Laramie Formation can be observed where Vindicator Drive cuts through a hogback near Centennial Blvd. (by vehicle drivers) or at the western edge of Ute Valley Park (by hikers).  At this locality, forces associated with the rising Rocky Mountains have turned the Laramie Formation up to near vertical , and a prominent hogback, held up by resistant channel sandstones, forms a spectacular topographic feature. Along most of the hogback, the beds are dipping to the east about 60 degrees.  During the late 1900’s and early 20^th century, the mining of coal was somewhat of a major industry in and near Colorado Springs. A number of coal mines operated in the PBA although I have been unable to locate much solid data on production.  Thorson and others (2001) produced a map showing perhaps a dozen known mines in the PBA.  Several old, but caved in, adits are visible along Popes Valley Drive and in the adjacent stream valley to the north.  A very visible mine dump is easily seen about 1000 yards south of the Vindicator Drive-Centennial Blvd intersection .  The last mine to shut down in the PBA was the Pikeview Mine (total production of 8,738,174 tons) in 1957 and located off Delmonico Drive immediately north of Rockrimmon Blvd (Thorson and others, 2001).  Also of interest is the fact that an oil well was drilled in the highlands near the mouth of Popes Valley.  The Rusina Ranch No. 1, spudded in 1959, was

abandoned at a depth of 485 feet.  I was unable to locate information about a possible pay zone but perhaps operators were aiming for a sand zone in the Pierre Shale.  At any rate, the well was abandoned early.

Although fossils, including plants, dinosaurs, fish, turtles, amphibians, and mammals have been found at a number of Colorado localities, I am unaware of  “ good “ body fossils in the PBA.  The carbonaceous shales of the Laramie Formation contain plant fragments, and many sandstones contain macerated bones and plants; however, I have been unable to locate collectable specimens.  Johnson (2002) noted that hard-to-identify dinosaur tracks are present in the area.  What the observer will notice, however, are numerous pseudo-fossils (Such as nodules, concretions, and differential weathering), animal burrows, and sedimentary structures.

Ute Valley Park may be accessed from a parking lot off Vindicator Drive or from a trailhead off upper Popes Valley Drive.  The best way to observe the geology is to take a stroll in the Park.  One never knows what interesting features will show up .

Sources Cited

Johnson, K.R., Ancient Denvers, 2002.  http://www.dms.org/main/minisites/ancientDenvers/index.html

Matthews, V., Lynn, K.K., and Fox, B., editors.  Messages in Stone: Colorado’s Colorful Geology, Denver: Colorado Geological Survey, 2003.

Thorson, J.P., Carroll, C.J., and Morgan, M.L., Geologic Map of the Pikeview Quadrangle, El Paso County, Colorado. Denver: Colorado Geological Survey, Open-File Map and Report 01-3, 2001.

Via Pick & Pack, May 2008

________________________________________________________________________

Volume 33, Number 5                          Pueblo Rockhounds                                 May 2008