Number 22 -1999

New Mexico Bureauof

Mines and MineralResourcesa division of

Nei~, Mexico Tech

Earth BriefsA publication for educators and the pul~lic-

contemporary geological topics, issues and eventsCarrizozo Lava Still aYoungster at 5,000 YearsOld: Flow was too young fortraditional dating methods, sogeologist tried a new way

By John Fleck, Journal Staff Writer(Reprinted withpermission from theAlbuquerque Journal, issue for August29, 1999)

She’s older than they think... I heard she’s hadthree vesicle lifts and has gone in for sandblastingfive times!

This IssueEarth Briefs-Better age estimates onsome New Mexico volcanic rocks

Have You Ever Wondered...What dogeologists learn from drilling wells?(page 2)

Postcard’from the Ice (page 6)

New Mexico’s Most Wan ted Minera Is(pageT)

Magnification of microscopic miner-als and glass (page 8)

Like an agingmovie star who’sbeen lying abouther age for years,the Valley of Fireslava flow outsideCarrizozo is older

than we thought. In geologic terms,it’s still a youngster.at 5,000 years ofage. But that’s considerably olderthan the 1,000 years scientists oncethought it was, said Nelia Dunbar, ageologist at the New Mexico Bureauof Mines and Mine’ral Resources.

Dunbar’s age calculations add to agrowing body of knowledge in the1990s about New Mexico’s youngestvolcanic features, the jagged .badlands known as "malpais.’"The Carrizozo lava flow stretchessome 50 miles from its volcanicsource at Little Black Peak, north ofCarrizozo in central New Mexico.It varies in depth from 30 to 50 feetand appears to have oozed out acrossthe landscape in two separateeruptions within a few hundrqd yearsof one another, according to Dunbar.The black lava flows still bear thesinuous look of a type of lava named"pahoehoe" by the Hawaiians.,

So short has the rock’s time onEarth been that plants have only

Lite Geology, Number 22 1 New Mexico Bureau of Mines and Mineral Resources

t

begun to take a ’foothold. The erosion

that will eventually weather the rocksdown,into dirt has barely begun. ’Butbecause they’re so young,Dunbar explained, determining theirages is difficult. Radioactive decay ofrare elements in volcanic rocks isfrequently used to date them, but theCarrizozo flow. isn’t old enough for

. the decay products to have built upenough to make it datable by thattechnique, she said. So Dunbarturned to a technique developed byNew Mexico Institute of Mining andTechnology geologist Fred Phillips.Phillips found that atype of chlorineis produced by rocks when they’rebombarded by Cosmic rays thatpenetrate the atmosphere and banginto rocks sitting on Earth’s surface.Measuring the chlorine in a rockallows the scientists to determinehow long a rock’s been sitting On the~urface,~exposed to cosmic rays.

Estimates in the 1950s and ’60s,based on visual observation of therocks, put the flow’s age at 1,000 to1,500 years, but Dunbar came up withan estimate of 5,200 years for theflow, give or take 700. That makesthe Carrizozo flow slightly older thanthe McCarty’s flow, located alongInterstate 40’east of Grants, whichDunbar and Phi!lips date a~ 3,900years old [compared to radiocarbondatea of 3,160 to 3,200 years old]*.

While thai might seem like a longtime in human terms, they’re mereyoungsters compared witfi some Ofthe more noticeable volcanoes inNew Mexico. The Jemez Caldera’west of Los Alamos, for example,blew up in spectacular eruptions 1.6million and 1.2 million years ago, andthe volcanoes on Albuquerque’s westmesa are estimated to be more’than100,000 years old [156,000 years old]*.

*Age estimates in brackets provided forcomparison.by Life Geolo,c,y editors

Have YouEver Wondered......What geologists learnfrom drilling wells?

Dr. Brian BrlsterPetroleum Geologist, NMBMMR "

"Boreh01es" are holes drilled intothe ground for all, sorts of reasons.They are often necessary for con-structing building foundations,.bridge’supports, and billbqard legs.They yield samples of ores that hostdesirable minerals in mining areas.Environmental testing of soils andground waters requires holes to bedrilled. "Wells" are deep b0reholesdrilled for the purpose of producingwater, oil, or gas. When a hole isbeing drilled, a geologist is probablynot far away. Although the hole initself inspires strange fascination, it is

the material that was removed fromthe hole while drilling, the boreholewall, and the fluids that might fill upthe hole tha’t geologists are mostinterested in studying.

While an outcrop of rock mightextend some distance horizontally ’and be ~appable over an area of theEarth’s surface, it reveals limitedinformation about what is below thesurface. Information from a borehole,on the other hand, y!elds signif!cantvertical information about what is.below the surface at one given point,but contributes only one data point toa map. When the information isavailable, geologists attempt to.combine surface data from outcropsand subsurface data from boreholesto gain a 3-dimensional geologicalperspective..

New Mexico Bureau of Mines and Mineral Resources 2 Lite Geology, Number 22

Wells are drilled by a number ofdifferent methods: hand-dug (shovel),auger (screw), percussion (raising dropping a weighted,bit)~ rotary(rotating a drill bit), and some daysoon perhaps, by laser. Rotary-drilledwells can be steered to drill an in-clined, or even horizontal boreholelWhatever the method used, geologicmaterials (soil, rocks, etc.) are brokenand removed¯ Of course the removedmaterial does not look like it didbefore being drilled. Such material isreferred to as "cuttings," which.typically range from fine powder tochips ~ few centimeters across¯Removing crushed and broken rockfrom the borehole is usually accom-

¯ plished by bailing it out with some"container or by "circulation¯" Circula-tion is achieved by pumping water,air, or viscous mud down the inside ofthe drill pipe, through holes in the bitat the bottom, and up the outside.ofthe pipe back to the surface (Figure 1).The circulating liquid or air cools thebit, suspends the cuttings, and ca/:riesthem to the surface where they are .separa.tedand washed, then examinedwith a microscope,(Figure.2).

Geologists record their observa-tions on a "log" of the well, whichincludes information such as theestimated depth from which the

¯ /cttttings were derwed, rock type,color, texture, fossils, porosity, odor,and other characteristics¯ The,geologist’s log also typically includesdata on the exact location of the well,record of daily drilling activity andprogress, results of formation pressuretests, shows of oil, gas or minerals,and description and measurement ofany fluids tha~ mig.ht flow into theborehole from porous rocks. Cuttingsare often retained for further labora-tory study and reference in the future.

Some wells are drilled with aspecia! coring bit, shaped like a

. pump

Cuttings settle out of mud In stpel pitand are collected for examination,storage, and proper~llspoeal.

, Drill plpe end blt areCuttings are broken~scraped ~ ’from borehole well. Drllllng

. mud flows through holes I~bit end rifts cuttings to thesurface.

, derrick

aurfece

Figure 1--Diagram of rotary drilling operation demonstrating circulation ofdrilling mud. Illustration by L. Gabaldon.

°Lite Geology; Number 22 3 New Mexico Bureau of Mines and Mineral Resources

. ]1"~ Ct’L’IIW ~

~ r,.’d )

,,,,,,,, ,,,

Figure 2--Typical drill cuttings of a ~II~ ". :’ ; 1vok’anic rock as seen through a /" ~ "Ill I~ ,.: 1 ~I J/l ~’j- . ]

doughnut, that drills arour~cl, and I ./

~--:i., i Z’ ’ %c~:~preserves, a hmg cylinder of rockcalled a "core" (Figure 3). Imagine /how mt,ch more information an ~.-unbroken core of rock would provide /’ N,,, it h,~k~ \ ff ~(compared to sand-size cuttings! For ~likc c’,.a,ncl ~ ~’~’N’~’~",exampk,, a core might reveal strt,c- N-~..-~ ~vM " ,~ ~’, .’tural information such as faults andfractures, sedimentary structures likecrossbedding, formation contilcts, oritems too large to survive intact ascuttings such as mineral crystals,fossils, or large pores.

Often once a well is drilled,"geophysical tools" ate lowered inthe hole with a wire cable. With thesetools, infi~rmation about subsurfaceformations such as temperature,natural gamma radiation, electricalconductivity, rock density, and otherproperties can be measured. Thesemeast, rements help the geologist.todetermine additional informationabout the rock types in which thewell was drilled. Additionally, thedepths of contacts between differentrock units can be determined accu-rately, haformation gathered by thegeophysical logging tools is recordeddigitally and plotted as paper "welllogs" that can be compared with thegeologist’s log (Figure 4).

Well information is expensive to

obtain. The cost of drilling a well canrange from tens of thousands tomillions of dollars. Such data isinvaluable, however, for understand-ing subsurface geology, especiallywhen data from different wells in anarea are compared. More than ahundred thousand wells have beendrilled in New Mexico by tens ofthousands of different companies andindividuals. Drilling is a rvgulatedactivity requiring permits, land-reclamation, and record keeping.Some of this well information is madeavailable to the public.

Where would a geologist look tofind well information for an area ofinterest? The New Mexico Bureau ofMines and Mineral Resources rriain-tains an archive of subst.rface infor-mation from wells drilled throughoutNew Mexico. The Bureau’s Subsur-face 13brary archives historicalrecords from more than q5,000 wells,

Figure 3-- l)oughnut-shaped coringbit. Photo courtesy of Baker ~lughesInteq, ! touston, "lbxas.

New Mexico Bt,reau of Mines and Mineral Resources 4 Idle Ge{dogy, Number 22

9O

Sample from 7690-7700’ Is light gray

J sandstone: grains are quartz (90%) and7700 feldspar (10%) with trace of chert and

10

20

3O

40 )

50

60

70

t’°)90

7800

are medium to coarse grained,modeistely sorted, and subround tosubanguler. The rock Is moderatelycemented with silica; estimate 10%porosity. There was a strong gas showIn the drilling mud at this depth.

Sample from 7740-7750’,1s dark grayfissile shale with pieces of cosilyorganic material and trace of pyrite.

Sample from 7780-7790’ Is brownlimestone: mlcrocrystalllne limemudstone to wackestone with traceof quartz slit, glauconlte, end fossilfragments.

0 150 depth(feet)

NATURAL GAMMA RADIATION(AME.tCA. PeT.O’EU. a.SnTUTS STA.OA.O U.OTS)

Figure 4--Geologist’s description accompanied by well log measured in theborehole following drilling. The log demonstrates that different rock typeshave different levels of natural gamma radiation (gamma radiation levelsincrease to the right on log; expressed in API Standard Units).

well logs from over 48,000 wells andwell cuttings from more than 15,000wells stored in a three story ware-house. The Core Library housesmany tons of core from more than2,000 wells stored, in six warehousesand includes cores from water,mineral, coal and petroleum bore-

holes. This publicly-availableinformation is free to access andwidely used by geologists in theirsubsu÷face studies.

Resources:

For information on drilling activitiesor subsurface data collections, contactthe New Mexico Library of Subsur-

face Data1 at NMBMMR in Socorro:

Drilling activity in New Mexico:Ron Broadhead (505) 835-5202email: ron@gis.nmt.edu

Well logs and cuttings:Annabelle Lopez (505) 835-5402

emaih alopez@gis.nm!.eduCore Library:

Elizabeth Fleming (505) 835-5139emaih efleming@,e, is.nmt.edu

"G

,b BO. .

References and RecommendedReading:

Clal"k, L.,,1988, The field guide to water wells.and boreholes: Halstead Press, New York,’155 pp.

Fleming, E. R., Hoffman, G. K., and Read, A. S.,1999, Drill cow, cuttings, & well informa-

.. tion available at the New Me;rico Bureau ofMines and Mineral Resources: NMBMMR,~)corn), 67 pp.

Swanson, R. G., 1981, ,qample examinationmanual: American Associatkm of Petro-leum Geologists, Tulsa, ll8 pp.

I.ite Geology, Number 22.

5 New Mexico Bureau of Mines and Mineral Resources

!

Postcard from the Ice: Working on the global climate puzzle........................................................... J .... 1 ................... 7r .............................

This email message wa~ sent by Dr.Nelia Dunbar on November 21, 1999from McMurdo Base in Antarctica,where it is now summer! Dr. Dunbar,together with Dr. Bill Mclntosh andRich Esser from the GeochronologyLaboratory at New Mexico Bureau ofMines and Mineral Resources/NewMexico Tech, are working on aNational Science Foundation fundedproject to sample a 600-m-thick,horizontally exposed section of icethat dates back nearly 500,000years. Geochemical analyses ofthe ice will provide a very longand detailed record of climatevariations.

I tow’s everything in Socorro?We’ve been down in McMurdo forahnost a week, after a smooth tripsouth. 7"he.field team this year.is madeup of 3 peoph’ from NM Tech, attd 3front University of New I tampshire.We’ve all setth’d in well to the gruelingproc,’ss of sortMg and packing our12,000’poumts of camp Rear, science

, equipment, fuel, sitowmobih’s, chainsaws,fi,od, etc...So, I think t/tat we hay,; a prettygood, competent crew, which will beimportant because of the difficult placewe’re working this year¯

Our scheduh’d put-in fl~ht is on Nov.24. We’ll be gofngfrom McMurito to a"pla¢e calh’d the Ford Range, in Marie

tt ~ ttByrd Land, in an LC-130 ttercuhsaircraft. The I h’rcs haw’n ’t beendistinguishing themselw’s this year,mainly because of regtilations that wereput in place last year after the "Here inthe crevasse" incident. But, they.’w’already landed at Ford Range this year,and shouldn’t haw’ arty troubh’ goingback.

We’ll spend one n(~,,ht at Ford Range,and will then be shuttled by Twin OtterIsee photol to a camp at the base ofMount Moulton to acclimatize fi,r ourfinal h~h altitude camp. This m~,,ht

seem kind of complicated, but it’s what wehave to live with because the Heros an’doing a limited number of "open fieldlandings" this year (going inki a placewhere tit, other landing has taken/,lace).We’ll spend about 3-4 days at theacclimatization camp, attd will then move.up to the final high camp (2,800 meters or9,186fl) when’ the n’al work will begin.

Our final camp is pn’tty isolated, attdalthough it’s not really that h~k,h, we’n’

trying to be well pn’pan’d because if we dohaw’. an altitude probh’nt, it would beimpossibh’ to get sonwone down to lowerelevation until, the Twin Otter couht conwattd get us. Obviously, if we lind a medicalpmbh’m, we’d have first priority’on theuse of the Otter, trot if the weather’s bad,the Otter wouldn’t be able to get to us.

So, we’re taking two Gamov bags, aswell as an altitu&’ drug called Diamox.The Gamov bag is a pretty good invention.It is a fi~, tightly seah’d bag that a wrsoncan fit in. There’,< a pressure regulator in

¯ the bag, and afiwt pump that can be usedto pump the bag up to pressures h~herthan the local pressun’. So, if you putsomeone in the bag at an altitude of 10,000fl, you can effecth~ely bring thent down toabout 6,000 fl. This can ch’ar up a lot ofaltitude problems, but you pretty muchhaw’ to h’ave the person in the bag untilyou can actually get them down to hm,er

elevation. One of our crew was with ateam climbing Denali last sumnter, andthey wen’ pinned down by a storm at17,000ft. Someone in another party hadsuch bad pulmonary edema thai he wascoughing up blood, but aftei" a day and a,half in the bag, he zoas abh’ to walk downunder his own steam. So, it sounds as ifttrey work.

When we’re at ou¢ final cantp, we’llbe colh’cting a "horizontal ice con’." The

ice at this place is pushed upagainst a rock outcrop, attd thewhoh’ section is turned up on itsside, n’sulting in ice with a wide ’range of ages being exposed at thesurface. We’ll be,collecting icefrom a tn’nch ahmg tit,’ surface.We know the ages of tit; ice I~’ca~sethen’ an’ dated volcanic ashesinh’rlayen’d With the ice. We’ll alsobe n’samf~ling the ash layers,redating the ones that we’ve alreadydated (fi,r mort’ pn;cise ages) attdrecollecting ones t/tat provedundateable bffon’, possibly due tosurface contantination.

.The ice cutting is going to take placewith a m~e, ttty ice trencher d,’s~ned byBill. If we can get some c(our d~,,ital

¯ photos downloaded, I iii attach one to afuture message. We’w’ had it out onsome frozen lakes around McMurdo, attdit ha~ worh;d well, attd !tas also attracteda Iotofattention! The ice tn, ncher holds

¯ tzoo chain saws, with the blades at abouta 60 degn’e attgh’ to the ice surface. Thesaws can be lowered into the ice, and thenttw trencher can be pushed ahmg,n’sulting in the cutting of a beautifulwedge c~ ice 60 cm deep at the point. Wethen pry the wedge out of the ~to~e, andtrim it to get the 10 cm by 10 cm block ofice that becomes our final sample.Whenever a new person sees the icetn’ncher, horn~r movies are mentio!wd,and I can see why!

Well, that’s about all fronl here.--Nelia

New Mexico Bureau of Mines and Mineral Resources 6 Lite Geoh,gy, Number 22

New Mexico’s Most

I)r. V. W. l.ueth, NMBMMR MineraloRis! & (’urah)r

Specimen from theContinental mine, (;rant County, NM

I)ESI~ItlI’TION:

~tNTEI) FOR:

IIIDEOI!T:

LAST SEEN ATLAI{GE:

AI,IASES:

CALCITEThis mineral is notorious for its vast number of rhombohedral crystal forms (more than 300!).Crystals can vary from obtuse, acute, tl~in tabular or long prismatic rhombs and scaJenohedrons(photo). Many modifications of the crystal form are possible, and crystal twinning is common.().ther forms include fibrous, lamellar, granular, earthy, tuberose, nodular, and pseudomorphs(false forms). I,uckily, other physical properties help to identify this mineral. Mobs Hardness:3. Cleavage: 3 at inclined angles (rhombohedral). Optical properties: transparent to translucent,double refraction observed in transparent pieces. Chemical properties: reacts with weak acidto form CO2. Color: white is most common, but any color is possible due to impurities. Chemicalformula: CaCO3, calcium carbonate, The n.ame originates from the I,atin word, calx, lime.

The most important use for calcite is in the manufacture of cements and lime for mortar. Alsoused as a flu~ for refining metal ores and as a soil amendment. Buildings are commonlyconstructed out of marble and lim’estone. Clear "iceland spar" was used to polarize lightbefore the invention of Polaroid plates. .

Calcite is a common rock-forming mineral, especially in sedimentary rocks where it is commoi’ilyknown as limestone. When composed of microscopic organisms it is called chalk. It forms mostcave deposits called speleothems. When metamorphosed it becomes marble.

Calcite is found almost everywhere in the state. Exceptk}nal examples of crystallized specimensinclude: Carlsbad Caverns and’ the mines at Magdalena, San Pedro, and Organ. Optical calcite(Iceland spar) was mined near the Harding mine.

Sp~lr, dog-tooth spar, nail-head spar, Iceland spar, and numerous rock names (e.g. limestone,travertine, tufa, onyx, caliche, etc.)

I.ih. (;eolo~y, Numbt;r 22 7 New Mexico Bureau of Mines and Mineral Resources

Magnification of microscopic minerals and glassNelia Dunbar( h’ochemist, NMBMMR

Gretchen Hoffman

Coal (,eohNisl, NMBMMR

Secondary electron imaging is a techniqtle that allows high magnification of verysmall samples. Rather than using light to magnify a sample, as is done with aconventional nlicroscope, tilt’ electron mk’roprobe LISeS a finely focused beam (if electronsthat sweeps back and forth across il sample stlrface, producing st,condary electrons thatare then nleastlred by a detector. The signals fronl tilL’ nleastlred electrons arereconstJttlted as an image on a television screen.

Ilecatise secondary electron hllages art’ usually nlagnified very highly, it is difficult toexpress tilL’ size (if tilt’ inlal2,e in conventional nleastlrenlent units, like t’entinleters orinches. As shown here, tilt, scale of secondary electron images is typically nleastlred innlicrons. There are 1,000 nlicrons ill I millimeter, or 10,l)00 nlicrons ill a centinlelt’r. Thegrooves and ridges on a fingerprint are abotll half a nlillimeter, or 50l) microns, apart.

Figure I--FMd of view = 4(10 microns; photo by C. I larpel.

Figtlre l shows a secondaryelectron image of volcalliC ash fronlMount I~rt,bus, Antarctica. MountI!rebt,s is a wflcano that eruptsseveral times a day, oftt,n producingash such as thai shown here. Theseash shards, each about tilt’ size of afine grain of sand, show feattlrestypical of glass from a volcaniceruption. The glass appearsstretched; tills stretching occurredduring tilL’ volcanic eruption, whilelilt, glass was still molten. Manybubbles are visible also. These wt’reformed by volcanic gas. The fibrousand spiky appearance of theseparticles is typical of volcanic ash.

The image ill Figure 2 also showsvolcanic ash particles from Mount

lirebus, Antarctica. The main ashshard exhibits a distinctive wrinklingahmg tilL’ top side. This wrinklingappears very similar to tilt’ ropystlrface of basaltic pahotthoe lavllflows, and ill fact, these type of flowsart’ fotlnd till Mount I!rebus.I Iowever, tilL’ wrinkles, or ropes, ontilt’ pahoehoe lava flows are about I0centinleters across, rather than It)microns or less, as on tilL’ particle.This illustrates that sinlilar geologicalprocesses can take place on manydifferent physical scales.

Figtlrt’ 2---FMd of view = 4(111 microns; photo by C. I larpel.

New Mexico Btll’t,atl ill Mines and Mineral Rt,sotlrct,s 8 I,ih’ (;eohNy, Ntlnlbt,r 22

The images’shown on this page are also Glass, but rather than beinG ash from a naturalvolcanic eruption, these are "fly ash" produced by burning coal. Fly ash represents partof the inorganic material in coal. Fly ash js formed from minerals, such as clay, quartzand feldspar, that melt during the coal combustion process, and then solidify in themoving air stream leaving the combustion chamber. This moving airstmam around themolten material helps to give most (greater than 60%) fly ash particles the strikingspherical shape seen in these images. Fly ash ranges in size from >0-44 microns.

Figt,res 3 and 4 are secondaryelectron images of fly ash samples fromArizona Public Service Coronado(k’nerafing Station, near Springervilh.,,Arizona. The coal burned to producethis fly ash is from I’ittsburg andMidway’s McKinley mine, north of(. ;allup, New Mexico. The hollowspheres packed with smaller spheresa re called ph,rospheres, and the 11ollowand empty spheres are calledcenospheres. It is believed theplerospheres were empty before bt,ingcracked, and then are filled withsmaller spheres during the fly ~lsh

¯ collection process. Analyses showmost of the spheres are ~ 65% Si(),,~2()% AI.,(),, and 2-5% Fe(), similar toglass.

I:ly ash is t,sed in cement andconcrete products for its pozzolanichalt,re. A pozzolan is a siliceous orsiliceous and altmlinous material that initself is not cementitious, but that willchemically react with calciumhydroxide in Ct’mt’nt to formcolllpOtlllds possessing cementitious

properties. New Mexico fly ash inpartict,lar is a beneficial admixtt,re toct’nlt’nt bt’cause of its tmique chemicalproperties. Fly ash also is used for largepours of concrett,, as it acts like ballbearings in the cement and facilitatesflow. It also lowers the curingtempt,rature, reducing the potential forcracking. 1,1 Iqq7, 1.56 million short tonsof fly ash from New Mexico coals wereust’d in ct’nlt’nlitiotls materials.

Figure 3--Field of view = 60 microns; photo by (;. I-Ioffman.

Figure 4--Field of view = 60 microns ; photo by (;. Itoffman.

I.ih’ (;colok, y, Nt,mbt,r 22 9 New Mexico Ilurt,at: of Mines and Mineral Resources

Magnification of microscopic minerals and glass, cont.,"-ihown below arc, secondary electron’image~ of natural minerals, rather than glass.

Minerals and glass have fundamentally different chemical properties, and these areapparent in the M’lapt, s of the two materials. Mint,rals have a fixed chemical formula, andthe atoms in minerals are organized in a framework structure. (. ;lass, on the other han~!,consists of randomly distributed atoms. Mineral grains, therefore, tend to haw’ moreregular, or I.~¢,xy shapes, and straight edges, whereas glass particles tend to be randomlyshaped, spiky or spherical.

Figure 5 is an image of a field ofvery small quartz crystals. Note thatthv same crystal shape is repeatedover and over and may look similarto quartz crystals that you have seenin larger rock samples, The repetitiveshape and I’ll~.llly straight edges arecharacteristic of crystalline mineralsrather than glass.

Figure 5--1:ield of view = 110 microns; photo by M. Chapin.

I:igurt, 6-- Field of view = 140 microns; photo by M. Chapin.

The image in Figure 6 Mlows twotypes of mineral shapes. The first, inthe upper part ()f the field of view,Mlows solid quart/crystals sinlilar tothose shown in the above image. Inthe center of the field of view is antlntlStlil] phl.’l’lOn]L’nOl’l, wilt’re ()Ill’

mineral (quartz) has formed a coatinga round a d ia mond-sha ped mineral(calcite). The calcite then dissolved,leaving a holh~w quartz coating in theM1ape of the former calcih’ crystals.

,;.y

New Mexico Ih,reau ot Mines and Mineral Resources 10 I,ih’ (,r(d(~,yy, Nl.iFFiber

Sources for-Earth Science InformationMineral Information Institute

The Mineral Information Institute/MII) works in cooperation with broad range of scientists andeducators to develop.mineraleducation materials for use in,theclassroom. Suppoi’ted bycorporations, foundations, scientificassociations, and individuals fromacross the nation, MII distributest~ese materials free to classroomteachers to supplement existingcurricula. Each year, more than 27,000K-12 classroom teachers in all 50states rec.eive teaching materials fromMII.

Subscriptions:Lite Geology began as a small Earth-science publication designed andscaled for Ne~v Mexico. Oursubscription list now includes a largenumber of out-of-state readers. Inorder to keep up with the demandfor this publication from outside ofNew Mexico, we now charge $4.00per year for’out-of-state readers.which covers the cost of mailing. Ifyou are a paid subscriber, you willfind a,number after your name on the

¯ mailing label. Thi~ numberrepresents the last Lite Geology issuein your subscription. When the issuenumber is’ the same as that on yourmailing label, it’s ti’me to renew yoursubscr!ption. If you have questions,please call (505) 835--5490.

Lite Geology, Number 22

For more information, contact:Nelson Fugate, PresicientMineral Information Institute501 Violet StreetGolden, CO 80401(303) 277-9190:fax (303) 277-9198mii@mii.orghttp://www.mii.org

Some websites for teachers

The American Association of

, Petroleum Geologists recognizes anoutstanding teacher in Earth Scienceeach year. Read about the currentaward winner at the address <http://www.aapg.org/explorer/archives/04_99 / teacher_98.html>.

The Geological Society of Americahas an informative website at <htti~://geosociety.org> that provides lots ofmaterial of interest to geologists andnon-geologiststoo. ’This one is wellworth exploring.

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11 New Mexico Bureau of Mines and Mineral Resources

Visit the Mineral MuseumThe Mineral Museum is located in

the Gold Building on the campus ofNew Mexico Tech in Socorro. TheBureau’s mineralogical collectioncontains more than !3,000 specimensof minerals and rocks, along withmining artifacts and fossils.

Contact information:Dr. Virgil LuethMineralogist and CuratorBob EvelethSenior Mining Engineerand Associate Curator

Address:Mineral MuseumNew Mexico Bureauof Mines and MineralResourcesNew Mexico Tech801. Leroy PlaceSocorro, NM 87801(505) 835-5140; 835-5420

Museum Hours: ’8:00 to 12:00 and 1:00 to 5:00weekdays10:00 to 3:00 most weekendsClosed Institute Holidays

t .

To Albuquerque

Macey MINERAL MUSEUM I \\ Center Gold Bldg, ’’ I \\

Mineral Resources ~,~ .

I r~’ ~l

d ===nn.

To Las Cruces

Lite Geology is published by New Mexico Bureauof Mines and Mineral Resources (Dr. PeterScholle, Director and State Geologist), a division ofNew Mexico Tech (Dr. Daniel H. Lopez,President).

Board of RegentsEx Officio

Gary Johnson, Governor of New MexicoMichael S. Davis, Superintendent of PublicInstructhm

AppointedRobert E. Taylor, President 1997-2003,Silw, r CityRandall E. Horn, Secretary[l’reasurer 1997-2003,AlbuquerqueAnn Murphy Daily 1997-2004, Santa Fe,

’ Sidney M. Gutierrez 1997-2001, AlbuquerqueKathryn E. Wavrik, Student Member 1999-2000,Socorro

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New Mexico Bureau of Mines and Mineral Resources 12 Life Geology, Number 22