New Mexico Mineral Symposium 2000
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Abstracts NEVADA 80 Laramie Cheyenne WYOMING Wendover 76 Salt Lake City UTAH COLORADO New Mexico Mineral Symposium 25 The Twenty-First Annual New Mexico 6 Denver 6 Mineral Symposium was held November 11 Ely 70 and 12, 2000, at New Mexico Institute of 50 6 Grand Junction Mining and Technology, Socorro. Following 70 550 Colorado Springs are abstracts from all talks given at the sym- 24 Pueblo posium. 191 15 2 93 666 PSEUDOMORPH CITY—THE MINERALOG- 160 ICAL TREASURES OF THE GRAPHIC– Alamosa WALDO AND KELLY MINES, MAGDA- Durango 285 OK LENA DISTRICT, NEW MEXICO, Robert 5 64 87 ARIZONA NEW MEXICO 666 Eveleth and Virgil W. Lueth, New Mexico 84 Springer Bureau of Mines and Mineral Resources, New 54 Mexico Institute of Mining and Technology, 191 Socorro, NM 87801 Santa Fe Gallup (Location 1 on index map) TEXAS 40 Flagstaff 40 Any discussion of the Magdalena mining district Kingman 7 in Socorro County, New Mexico, ultimately 666 Albuquerque 6 focuses on the beautiful blue-green gem variety 180 Clovis CA 60 of the mineral smithsonite and for good reason. 17 54 Specimens from the Kelly mine have become 60 Socorro famous the world over for their superb color and 1 Phoenix 380 luster. The Kelly mine, as a result, has tended to 10 Globe 666 Roswell enjoy all of the mineralogical accolades over the 180 70 25 past 50 yrs or so, and our very own mineralogi- Silver 70 Alamogordo City cal museum here in Socorro is responsible, at 8 Hobbs 4 least in part. Las 3 Cruces A reason for the fame of the Kelly is the C. T. Tucson 10 Carlsbad Brown collection. Acquired by the New Mexico Deming 19 180 School of Mines in 1938, the collection contains 20 El Paso an abundance of superb smithsonites, most of TEXAS which have been on open display to the public 285 Gulf SONORA CHIHUAHUA 10 since that time. of 10 However, with the mineral museum’s acquisi- California Van Horn tion of the Mahlon T. Everhart collection in 1990, it became apparent that there is another mine in blatonite. A second new uranium mineral from The basal siltstone is the host for most of the the district that has produced an equally impres- the mine has recently been submitted to the mine's minerals. They are found as microscopic sive array of mineralogical treasures. That mine International Mineralogical Association for crystals locally concentrated in two different is the Graphic–Waldo, located over the hill to the approval. The Jomac mine is the world's second assemblages, a copper sulfate assemblage and a north of the Kelly. C. T. Brown’s mining partner reported location for the minerals swamboite blatonite assemblage. Minerals found in the cop- in the district was Asa B. Fitch, and he, like and mbobomkulite. The mine saw most of its ore per sulfate assemblage include anhydrite, car- Brown, assembled an impressive collection of production in the 1950s and had an active claim bonate-cyanotrichite, antlerite, malachite, azu- minerals. Whereas Brown tended to focus his until 1985. Obviously, the mine was a wonderful rite, serpierite, alunite, sparse smithsonite, bolt- attentions on the Kelly, Fitch collected primarily source for interesting minerals. Unfortunately, woodite, and very rare brochantite. The blatonite at the Graphic. Thus, the two collections comple- the mine lies within the boundaries of the Glen assemblage can have sparse amounts of the min- ment one another. Mahlon acquired the Fitch col- Canyon National Recreation Area, and it was erals found in the copper sulfate assemblage, but lection during the 1930s and subsequently reclaimed in 1992. Mineral collecting since then has a greater amount of carbonate mineraliza- donated it to the museum in 1990. has not been allowed. tion. This latter assemblage has blatonite; ura- Specimens in the Fitch/Everhart collection are The Jomac mine's three adits lie in the nopilite; increased amounts of malachite and remarkable in that they clearly demonstrate that Shinarump Conglomerate Member of the smithsonite; sparse amounts of swamboite, zinc carbonate has tended to replace many of the Triassic Chinle Formation. Petrified wood, coal, sklodowskite, rutherfordine, schoepite, meta- other ore minerals in the Graphic orebody— and sooty black organic debris are scattered schoepite, meta-autunite, and mbobomkulite; sometimes with spectacular results. Examples of throughout the conglomerate. The organic the recently submitted uranium mineral; an such replacements are seen as smithsonite remains, apparently setting up a reducing envi- unidentified orange uranium mineral; and some pseudomorphs of barite, calcite, cerussite, ronment, make the sediments more amenable for fine-grained, yellow uranium minerals. Impur- cuprite, galena, and native copper. With this pre- the precipitation of primary minerals. Uraninite ities in the minerals cause various changes in sentation, the authors hope to place the and the sulfide minerals pyrite, chalcopyrite, their habits, making identifications challenging. Graphic–Waldo back where it belongs—on an and sphalerite were deposited. Tiny specks of Cobalt and nickel are common in trace amounts equal mineralogical standing with the Kelly. cuprite are very common in a basal siltstone, but in most of the secondary copper minerals. cuprite may or may not be a primary mineral. The Jomac mine's portals were sealed with MINERALOGY OF THE JOMAC MINE, SAN Oxidation of these minerals led to the formation mortar and backfilled, and the access road has JUAN COUNTY, UTAH, Patrick E. Haynes, of an unusual assortment of mostly copper and been blocked with boulders. Despite the recla- P.O. Box 1531, Cortez, CO 81321 uranium minerals. The minerals hematite, mation efforts, previously recovered specimens (Location 2 on index map) jarosite, hydronium jarosite, and limonite are are producing interesting results. Two of the The Jomac mine is located on Brown’s Rim, in common. Also common in the conglomerate are remaining unidentified uranium minerals have the White Canyon mining district of San Juan coconinoite and metazeunerite. A mixture of unique X-ray diffraction (XRD) patterns. County, Utah. It has recently become the type asbolan–birnessite occurs as dendritic smears on locality for a uranium-carbonate mineral named fracture surfaces. TAKING CARE OF THE LITTLE THINGS: February 2001 NEW MEXICO GEOLOGY 21 THE MICROMOUNT COLLECTIONS AT (Location 4 on index map) studying the crystal fill and textures in THE ARIZONA–SONORA DESERT MUSE- One of the geologically interesting features of spherulites and geodes, we hope to piece togeth- UM, Anna M. Domitrovic, Collections Manager, Rockhound State Park, in southern New Mexico, er the different processes through time that Mineralogist, Arizona–Sonora Desert Muse- is the presence of many spherulites within the formed them. The banding found within some um, 2021 N. Kinney Road, Tucson, AZ 85743 rhyolite lava. The spherulites range in size from spherulites and geodes consists of multiple lay- (Location 3 on index map) less than 1 mm to greater than 30 cm, and many ers of different colored agate, chalcedony, and The Arizona–Sonora Desert Museum’s Perma- are solid, concentrically zoned, dark-gray to local quartz and may have been formed by fluids nent Mineral Collection has 14,250 catalogued pinkish colored material with a distinct, nodu- supersaturated in silica (Fournier, 1985). The dif- specimens. Over the course of its 25-yr history, lar, reddish core. Others consist of the same ferent colors of the bands are a result of trace minerals have been purchased, exchanged, and material but are partly hollow. A third popula- amounts of impurities, such as iron (red), man- donated. Acquisitions have come one specimen tion consists of two distinct parts: a dark-gray to ganese (black, pink), cobalt (blue, violet-red), at a time or, especially in the case of the micro- pinkish outer part that appears similar to the copper (green, blue), chromium (orange-red), mounts, thousands in one acquisition. material that forms the solid spherulites and a nickel (green), etc. The micromount collection is extremely impor- white, blue, or gray inner part, or core, which is Faceted quartz crystals indicate that the fluids tant to the Desert Museum. Because many rare or recognizable as agate, chalcedony, and quartz were somewhat supersaturated with silica, and unusual minerals generally occur only as micro- crystals. These two parts appear to be a shell and that precipitation occurred under relatively scopic specks, micromounts provide the means a filling. This type of filled spherulitic form is slow-changing conditions (Fournier, 1985). Tilted of acquiring as many species as possible that commonly called a “thunderegg.” In order to thundereggs, locally found at Rockhound State occur within the boundaries of the Desert gain some insight into the process by which Park, are filled with horizontal layers of agate Museum’s interpretive realm—the Sonoran these spherulites form, samples were examined and chalcedony that are overlain by concentric- Desert region of Arizona and Baja and Sonora, using back-scattered electron imaging and quali- banded agate and chalcedony; the contact Mexico. The micromount collections are valuable tative X-ray analysis and imaging using a between the layered and banded agate resembles research tools. They allow researchers to see rep- Cameca SX-100 electron microprobe. Microprobe an angular unconformity. These thundereggs resentative minerals of a given locality in one sit- examination of the "shell" part of Rockhound record either small local landslides or tilting of ting. They provide mineralogists with a visual spherulites shows that they are composed of local fault blocks within the Little Florida means of identifying other species by physical intergrown crystals of quartz (SiO2), alkali feld- Mountains while the crystals were precipitating comparison when other means of identification spar (K,Na)[AlSi3O8], plagioclase feldspar from the fluid (Shaub, 1979; Colburn, 1999). such as X-ray and scanning electron microscopy Na[AlSi3O8]-Ca[Al2Si2O8], and magnetite (Fe3O4).