9th CIRCUIT COURT OF APPEALS

Last week a federal appeals court handed down an interesting decision: that the United States Forest Service could no longer charge auto parking fees for hikers (perhaps even rock hounds)  heading to certain trails in the Catalina Mountains near Tucson, AZ.

The 9^th Circuit Court of Appeals ruling could bring an end, or at least change the outlook, on fees gathered by the USFS to pay for improvements.  I am uncertain if the ruling applies only to the Catalina Mountains or to fees the USFS collects at numerous other locations (probably the latter).  As I understand it, the USFS has collected, since 1996, parking fees for hikers in some of the canyon areas of the Catalina’s. Since the hikers were not using improved facilities (campgrounds etc.), fees could not be charged.  

The court case is Adam et. al. v USFS.  Perhaps it will be appealed by USFS?  I would assume that a USFS ruling would also apply to lands managed by BLM, and perhaps other federal agencies. 

 

This case may have wide implications for recreation and other fees assessed by federal land managers.  But again, it may not!  I look forward to hearing about future results.

 

mike

 

 

COPPER RIVET MINE: COLORADO

VUG IN SANDSTONE COLLECTED AT COPPER RIVET MINE.  NOTE GEMMY CLEAR CALCITE PARTIALLY ENCRUSTED WITH GREEN MALACHITE AND BLUE AZURITE.  NOTE TINY GREEN ACICULAR CRYSTALS NEAR LOWER LEFT PART OF SPECIMEN. 

At the Tucson Electric Park/Kino Complex show I purchased an interesting specimen collected from the Copper Rivet Mine (uranium and copper) in Mesa County, Colorado, about 10 miles south of Gateway (Juanita Arch Quadrangle, 38.535ºN, 108.975ºW).  The seller indicated the specimens were collected in the early 1960's and that he had purchased a flat for resale; I immediately snapped up one!

Thus far I have not had access to an appropriate geological library to locate geological information.  However, the mine is very near the Utah-Colorado state line in an area of copper production; MinDat (www.mindat.org) noted that the Copper Rivet is located several miles north of the Cashin Mine.  The North Jeffco Gem and Mineral Club collected at the mine in a 2000 field trip that is described at peaktopeak.com/njeffco/2000/copperrivet/copper00_rep.php.  They described the hike to the dump and mine adit as 'strenuous".

The specimen, ~2.5 x 2.5 inches, has gemmy clear calcite crystals with coatings of boytrodal malachite and microcrystals of azurite appearing as "blobs".  And, there are quite tiny, green acicular crystals of what I am guessing is malachite although their green color is a different shade than the boytrodal form.  MinDat listed the following minerals known from the Copper Rivet: Azurite, Baryte, Bornite, Calcite, Chalcocite, Chalcopyrite, Luzonite, Malachite.

PHOTOMICROGRAPH OF SPECIMEN SHOWING BOYTRODAL MALACHITE (~2 MM), BLUE AZURITE, CLEAR CALCITE.

PHOTOMICROGRAPH OF SPECIMEN EMPHASIZING GREEN ACICULAR CRYSTALS.

KINO SPORTS COMPLEX SHOW 2012

VENDORS SELL WARES FROM RV'S OR TABLES.

The Tucson, Arizona, "rock show" is much more than the four-day main event, the Tucson Gem and Mineral Show, held at the Tucson Convention Center  The event this year will focus on "Arizona Minerals: so I expect to see, among other items, some really great specimens of azurite and wulfenite and malachite.  However, there are something like 40 total venues scattered throughout the city.  One of my favorite shows is the former Tucson Electric Park (TEP) Mineral and Gem Show now know as the Kino Sports Complex Rock Show.  This show, south of downtown along I-10, is set up on a series of soccer fields with free parking, free shuttles, and offers the opportunity for "dry camping" at $10 night.

The great thing about the Kino Show is, in my opinion,  the total lack of pretense among the vendors.  Sellers at one area come and park their RV's and sell items off tables and tarps, or perhaps from the bed of their pickup. There are the usual suspects such as Mt. Ida quartz, Moroccan trilobites, and agates from across the world.  However, a little searching and visiting with usually friendly vendors will often produce specimens of incredible beauty and perhaps a little scarcity.  One specimen of interest that I picked up was ~2.5 x 2.5 inch rock with encrustations of calcite, azurite and malachite collected from the Copper Rivet Mine in Mesa County, Colorado.  The vendor told me that he had purchased a flat of Copper Rivet specimens from a person liquidating their collection and that the minerals were picked up in the 1960's.  More on this specimen later.

At an adjacent field field vendors have set up GIANT tents and sell a variety of beads (10's of thousands), lapidary equipment, petrified wood, taxidermy mounts, hats, hundreds/thousands of amethyst cathedrals, and a variety of other funky items.  Some of the specimens were truly unique such as a hunk of schist about the size of a "Smart Car".  Or perhaps dyed amethyst cathedrals, or a two ton rock with a stain of blue copper material.

At any rate, the Kino Show is a great place to wander around for several hours, if for nothing else to observe more amethyst cathedrals than you have ever seen in one place. 
mike

COYOTE BONES FOR SALE?  WHY?

THIS SAW MAY BE WHAT CSMS NEEDS IN THE LAP SHOP!

ROCKS FOR SALE BUT A FLAT BED TRUCK IS NEEDED FOR HAULING.

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THE OBLIGATORY CEPHALOPODS

BEADS ANYONE?

EVERYONE NEEDS AN AMETHYST CATHEDRAL.

PETRIFIED WOOD FROM INDONESIA.

BAKING NEW MEXICO SHALE

THE CRETACEOUS PIERRE SHALE INTRUDED BY A DIKE NEAR MP 435-436 ALONG I-25 IN NORTHERN NEW MEXICO.

The Raton Basin is a structural basin--beds dipping toward the center-- straddling the New Mexico-Colorado state line immediately east of the Rocky Mountain front.  The basin is asymmetrical with the basin axis closest to the bounding Sangre de Cristo Range on the west (steeper dipping beds).  The eastern boundary includes the Apishapa Arch and Las Animas Arch (Colorado) and Sierra Grande Arch or Uplands in New Mexico.  Tertiary sedimentary rocks are well exposed in the center of the Basin while the Cretaceous Pierre Shale often crops out along the exterior boundary.

The Basin is probably best known for 1) the dikes associated with the  Spanish Peaks granitic intrusives near Walsenburg, Colorado; 2) the coal mines and coal bed methane wells associated with the Cretaceous Vermejo Formation and the late Cretaceous-early Tertiary Raton Formation near Trinidad, Colorado; 3) the Miocene volcanic rocks capping the mesas at Raton Pass; and 4) exposures of the K-T boundary in the Raton, New Mexico, and Trinidad areas.

Most visitors to the Basin are impressed with the numerous radiating dikes near Walsenburg and La Veta, and they are correct.  These dikes are pictured in hundreds of textbooks and popular reading materials and are recognized by geologists the world over. 

However, the place to get “up close” to an igneous intrusive is to examine the smaller dikes cropping out, generally perpendicular to the basin axis, across the state line in New Mexico. Along I-25 near MP 436 and 435 (south of the city of Raton) the interstate cuts through two dikes and exposes their central core as well as the adjacent baked Pierre Shale.  The metamorphic aureole of the Pierre extends about 12-15 feet on either side of the dike.  The shale has been altered to a hornfel.  The age of the intrusion is either Eocene or Oligocene.

mike

 

GEOLOGIC MAP OF THE RATON BASIN, NEW MEXICO AND COLORADO.  MAP COURTESY OF USGS GEOLOGICAL SURVEY BULLETIN 2184-B. 

THE DIKE IS HARDER THAN THE SHALE AND THEREFORE IS MORE RESISTANT TO EROSION.  NOTE THE BAKED SHALE ADJACENT TO THE INTRUSION.

 

A NEW TOY

QUARTZ CRYSTALS FROM LAGARITA, COLORADO.  LENGTH OF LARGEST CRYSTAL (TERMINATED ON RIGHT) IS ~1.2 MM.

Well the holiday season, at least for me, has come and sort of disappeared; and, it certainly was a pleasant experience.  A request to Santa involved "rocks and minerals"--no surprise here.  My subscription to Rock and Gem was renewed and a Celestron Handheld Digital Microscope appeared under the tree!  The latter has finally been unboxed and plugged in and experiments have started.  I am still learning and trying to understand the mechanics (for example, can the photos include a mm bar?); however, preliminary results look promising.  More information will be forthcoming.

mike

TINY WULFENITE (~.25 MM) CRYSTALS EMBEDDED IN CALCITE FROM BOX ELDER COUNTY, UTAH.

AZURITE CRYSTALS FROM MORENCI, ARIZONA.  LARGEST CRYSTAL IS ~.6 MM.

CALCITE SAND CRYSTALS: WYOMING

SAND CALCITE CRYSTALS COLLECTED ~1966 RATTLESNAKE BUTTE, SOUTH DAKOTA.

In a Blog posting dated January 8, 2014, I note information about calcite sand crystals collected several decades ago from an isolated butte in Jackson County, South Dakota.  The crystals are well known to the collecting world and small quantities appear each year on the market.  The specimens are from Rattlesnake Butte (aka Snake Butte or Devil’s Hill), a locality on the Pine Ridge Indian Reservation that is now off limits to most collectors.

Essentially, the crystals are composed of sand, perhaps ~60%, and calcite, approximately ~40%.  They occur as double terminated, hexagonal scalenohedradon crystals sometimes modified by rhombohedrons.  Crystals range in length from less than one inch to perhaps 15-20 inches (these are rare).  The crystals are found in a bed of coarse sandstone, about three to four feet in thickness, at the top of the butte, probably in the Miocene Arikaree Group.  Wanless (1922) believed the crystals were formed post-deposition by the action of ground water in eolian (wind blown) sands, perhaps in a spring environment with pressure from overlying rock.  Newer studies using petrographic and scanning electron microscopes (Cirone and Law, 2005) indicated that the compaction of the sand grains was minimal and that presumed fluid pressure was higher than normal groundwater flow.  In other words, they seemed to rule out the spring water theory of Wanless but failed to provide an adequate explanation for the crystal formation!

In my Blog article I noted that calcite sand concretions are known from only a few other localities around the world, including: the Imperial Valley-Salton Sea area of California; in Monterey County, California, at a locality in Tertiary rocks at Cholame Hills; from Fontainebleau, France; and somewhere in Saudi Arabia.

It then was a complete surprise to see a dealer at the Flatirons Rock and Mineral show in Longmont who was offering a few nice sand calcite specimens, from an “old collection”.  The only collecting locality noted was from near Wheatland, Wyoming.

The mention of Wheatland jogged something in the far recesses of my mind since the area was mapped, back in the 1960’s, by an  acquaintance of mine:  Geology of the Fort Laramie Area, Platte and Goshen Counties, Wyoming (Laura McGrew).  So, I dug out the publication and there it was, in black and white: In some areas, crystalline calcite has formed authigenically around sand grains, resulting in calcite sand crystals. Some of these crystals are as much as three-fourths of an inch in diameter and 2 inches in length… The upper unit of the Arikaree formation, which is exposed in the northwest corner of the map area, is about 200 feet thick and consists of fine- to medium-grained soft massive orange-gray sandstone. Small limy spherical concretions covered with irregular, partly formed calcite sand crystals also are common.

So, it now appears that the calcite sand crystals from Wyoming occur in rocks similar to the “type locality” at Rattlesnake Butte in South Dakota.  The “find” at the show was just a bit of serendipity.

REFERENCES CITED

Cirone, A. and E. Law, 2005, Microstructure of Calcite Sand Crystals and Implication on its Crystallization Process (abst.):  Geological Society of America Abstracts with programs, v. 37, no. 1, p.59.

McGrew, L., 1963, Geology of the Fort Laramie Area, Platte and Goshen Counties, Wyoming: US Geological Survey Bulletin 1141-F.
 

Wanless, H. R., 1922, Notes on Sand Calcite from South Dakota; American Mineralogist, v. 7, pp. 83-86.

SAND CALCITE CRYSTALS FROM GOSHEN HOLE, WYOMING.  LARGE CRYSTAL IS ~5.5 CM. 

EXOTIC WATERFALL IN COLORADO

Rifle Falls State Park is located a few miles northeast of the Garfield (CO) County city of Rifle.  The park is a small area, as state parks go, with ~48 acres, but has some spectacular scenery anchored by the falls themselves. The area surrounding the falls is a lush oasis of exotic looking vegetation, cascading waterfalls, and crystal clear streams.  The Leadville Limestone (Mississippian in age) is the bedrock at the falls with East Rifle Creek providing the water.  The Leadville is quite porous (in other parts of the state the Leadville is the host rock for metallic deposits) and numerous small caves may be observed in the Park.  Ground and surface water flowing over and through the Leadville has dissolved parts of the limestone and the water has become saturated with calcium carbonate.  As East Rifle Creek cascades, ~70 feet, over the Leadville Limestone cliff, a gas, carbon dioxide, is released and the chemistry of the water is changed and calcium carbonate is rapidly deposited in the form of travertine, a dense, usually banded, sedimentary rock. It appears that the Creek has changed course many times over the past centuries as the travertine wall extends many hundreds of feet on either side of the current falls.