QM-10
PLATE 1
Key to M;...,..liutloft : STAT£ Of OREGON Conruto Dl GToM!old R.ocko1 DEI'All'Oj[!'ff OF GEOLOGY AND lollNERAI,. IMOUSTIIlllS E.IMI,.. Minooo ond PToopocb> Mincn.li.o.od Zona> Proop«ti... AnNI ... GEOLOGIC RECONNAISSANCE o/ rht CENTRAL PORTION o/ rM WALLOW A MOUNTAINS OREGON 1938
LEGEND
Q•l
AllUVIUM AND GLACIAL METAMORPHIC LIM(S10N£ "NO Sf.DIMENT'S MARBU Mo"l' fiu ra•....l ...d•• 14'h"•· ~·"~• bluri, und ml•><<•fo.,ilof.,.••• BASALT /lu>uh ~oJ>O< onl<>l>«io-• .. mil~r lo CoiM"'bio< R!-mo ,.,,J J,,.l.,·o/otfdb.,irr, h~r "'irh n~mlo• rond "'"''~'"""" --JEll--
SCALE G...,k.Jy bv o. Smoth; by 8,,., l..'nuN Stot .. Fomr S.tnC< w.,..,. ·""''"«< Ro\ C. TrWallowa Mountains was carried out by the State De dense, tough, dark-green rock, A porphyritic phase con being worked when the price partment of Geology and Mineral Industries in order of copper rises, and favorable transportation is devel to tains lath-shaped feldspars that attain a length of five These basalt flows cap the ridges determine the areas or zones most suitable for prospect along the north oped in the area. centimeters and occur in rosette-like groups in a dark, ern edge of the Wallowa Range. They underlie the Vlallowa ing; to definitely oe~tain eliminate localities as being fine-grained matrix. The phenocrysts are thought to be Grande Ronde valley unfavorable prospecting at an elevation of about 4500 ,·oat Lead and Zinc ground; to prepare a reconnais secondary and the greenstones to be of extrusive rather and have sance geologic map illustrating a very flat dip. They next appear high o - the the conclusions; and to than intrusive origin. §( Another common phase of the crest of the ridges to t he south carry northward the data published at elevations of about Lead and zinc minerals were not noted in the course by this Department as rock is a breccia of greenstone fragments imbedded in a 6000 feet and r i se to 8500 feet before Bulletin no. 3, "The Geology of a they disappear. of this survey although unconfirmed reports of lead and Part of the Wallowa matrix of green, fine-grained tuff or lava. Farther south and toward the vrest and Lountains, Oregon", by Clyde Ross. east, the lava is zinc from the B. C. Basin, east of Hurricane Creek, we!"e several thousand feet thick and overlies all other form received, Some further prospecting might The greenstone of the southern area appears mega be done in the ations at the lower elevations. On the south side of B. C. Basin to determine the value of these deposits; Extent o.f the Survey scopioally to be a dark-green, granular, gabbroi d rook, the range, only Bennetts Peak is capped with basalt otherwise it is su~ g ested that a search for lead and c~posod mainly of pyroxene. It may represent a contact (elev. 6000 ft.) but a few miles west and south, Five geologists and four student assistants basalt zinc minerals be directed to more favorable localities. spent metamorphic phase of the sediments correlative with the becomes the predominant rook type. five weeks in July and August, 1938, plus an additional Hummingbird Peak metamorphics. South of Bennetts Peak a ·.•eek by two .geologists and two student assistants. t!olybdenum Geo large area of grey to greenish-altered rocks, apparently The basalt is assumed to correlate with Columbia logic contacts and belts of mineralization were studi ed of volcanic origin, was included with the metamorphic River Basalt and i s therefore of middle Miocene age. Molybdenite, the molybdenum sulfide, and molybdi t in some detail. Rooks and formations were classified by sediments. e , field methods. The map and data must be regarded as the molybdenum oxide, oocur at many looalities . Tlomarbles. The survey parties were directed by Earl K. Nixon, sometimes minor amounts of pyrite and copper minerals. Metamorphic Sediments Size vari es from r ock flour to boulders 10 f eet in dia Direct or of the State Department of Geology and Mineral Molybdenite is less frequently finely disseminated wi ,. meter. in the taotite zone and may be associated with minute Industries, who kept in close touch with the progress of The metamorphic sediments throughout the region map t he work by correspondence and field amounts of scheelite. Molybdenite and copper minerals inspection. Warren ped, conformably overlie the greenstones. Several hori The great lateral and terminal mora i ne that impounds D. Smith was geologist seem to have some assooiation, as flakes of molybdenit e in charge of field parties, zons of marble and limestone are interbedded with these Wallovra Lake is undoubtedly one of the best preserved of assisted by Ray C. Treasher were noted at most of the oopper prospects. and John Eliot Allen of the sediments. They tend to be highly calcareous near the its kind in the United States. The lateral moraine is State Department of Geology and Mineral Industries, and marble contacts, and contain Triassic fauna. The argil 800 f eet high at the upper end and its smoothly sloping The general ooourrenoe o~ molybden Lloyd Ruff and Wayne Lowell, geologists. Fred Hoffstaed, i te in the tact litic portions of the group range from dark, fossilifer si des strongly suggest an artificial embankment. The ita should encourage further prospecting \Yilbur Greenup, James Weber, and Herbert Harper for thi s miner were ous shale to dense, hard argillites or hornfels that are moraines at the mouths of Lostine River and Hurricane al. The contact zones and areas of student assistants, with Forrest Landeen as cook. mineralization shovm Almost "basaltic" in appearance, and "clink" like a Creek are di stinct physiographic features. They are on the small map may be considered as a guide to such phonolite. Fine- g rai~ed disseminated pyrite appears in well developed on the east side of Eagle Creek, and a localities, Acknowledgements While the law price of copper does not per many of these. Bending is apparent even in the more al small terminal moraine with two lobes impounds Two Col or mit the economic development of many of these prospects tered types but slaty cleavage is seldom developed. Luke, just south of Hummingbird Mountain. The tops of for copper, the higher The topographic base was supplied from the Forest priced molybdenite may stimula te the lateral moraine ridges on Eagle Creek are 1000 feet the mining of a deposit from which copper could Atlas of the United States Forest Service; sheets 8, 9, be recov Where these sediments have been intruded by the above the valley floor. Granodiorite erratics found on ered as a by-product and further 12, and 13 of the Wallowa National Forest, and sheets 4, the value of t loe prop granitoid rocks they are more or less altered and silic the sides of the Lostine canyon 2500 feet above the erty. and 5 of the Minam Division of the Whitman Iglacier. Tungsten these topographic maps made it possible to cover the textural variety of hornblende-gneisses, schists, and area effectively. Special mention is made of the coop hornfels have been developed and no definite contact oan Recent alluvial wash within the valleys consists Tungsten, occuring as eration of Mr. C. Buck, scheelite, the calcium tung J. Regional Forester; Mr. J. F. be drawn between the sedimentary and i gneous rocks. of sands and gravels derived from glacial debris. The state, has about the same association Erwin, Supervisor of Wallovta National Forest; as does molybden Mr. Lester wide and sometimes marshy flats along many of the ite. The mineral is very difficult to identi fy Honcrief, Supervisor of Vlh.i tman Nat ional Forest; in t he Mr . V. On the Hurwal Divide, near B. c. Basin, a seri es of streams are composed of sandy and bouldery material field as it appears muoh like quartz. Only by panning, H. Flack, in oharge of Maps and Surveys; as well as many argillites, hornfels, impure limestone and fossiliferous, f i lled in behind glacial rock or morainal dams since of the staff, or by the use of the ultra-violet lamp, can it be calcareous shale more than 1000 feet thiok overlies and the retreat of the ice, readily determined, Many areas may prove to have grades downward into t he grey marbles and limestones. A scheeli te deposits, and will be found only ile cetailed ~. Clint liai&ht, editor of the Joseph Herald, mr. long ~le Creek the shales are fossiliferous and in prospeoting with a pan or lamp. G. :r. Green, Mr. Jos. La Gore, Mr. Jack Baxter, and w-. clude larg~ lenses of marble. South of Be~~etts Peak, STRUCTURAL AND HISTORICU GEOLOGY Charles Seeber gave invaluable assistance. The mer several thousand feet of rocks of volcani c origin appar Limestone and Marble chants of Lostine, Enterprise, and Joseph contributed ently overlie these shales, and are mapped with them. G r e ~tly to the administration of the field parties. Great lava flows ·and tuff beds fanned some time Limestone an!! marble for use in cement manufactu;•e , Triassic fossils indicate Triassic age of these prior to mi ddle Triassic t ime, probably in a manner sim lime, building stone, and interior trim have been d~ c . · se dirnents. ilar to the Miocene basalts. The land area t hen began cussed in detail by Parks, y, Moore y, and Hodge 3/ • to sink, and it was covered by salt water in which .were the latter giving computed costs of quarring, shipping, Published reports on the geology of the central Marbles and Limest ones deposited limey and clayey sediments. These later be and marketing. Analyses indicate that the quality is uortion of the Wallowa Mountains have been concerned came the metamorphic sediments with limestone interbeds, satisfactory for cement and lime purposes. ~ith the limestone occurrences, (particularly the Black The marbles and limest ones are interbedded with the end fluctuati ng condit ions of depth of water and source ~~rble & Lime Company's quarry in sec. 19, T, 2 S., sedimentary series as relatively narrovr bands that wi den of material accounted for the cr~nges in sediment, The The black marble of the Black Marble Lime Comp R, 44 E.), with generalized & statements as to the geology in many places to several hundreds of feet. Isocli nal shallow sea bott om svramed v;ith invertebrate life such any's quarry, seo. 19, T. 2 S., R. 44 E., takes and some pertinent a beau data on the physiography, glaciation folding within the largest marble masses greatly exag as corals, and several types of shellfish. tiful polish, and the white calcite veinlets and repla and scenery, and a few reports on detailed areas or gerates their true thickness . ced fossils relieve the monotony of the black color prospects. A selected bibliography is given at the Leek of Jurassic sediments indicates that the land Development of this natural resource shoulc receive fur close of this report. These rocks have frequently been called "limestone" emer&ed from the sea and the Triassic formations were ther study. but they have all undergone metamorphism and should pro folded. As folding progressed and the earth's crust was perly be called marbles. Color varies .f rom fine-grained weakened, an underlying pool of mol ten rock ( a magma ) Granite for Building and Monumental Stone black (Black Marble &: Lime Co. quar~y ), to pink (Po i nt sought its way upward, making more progress through the GEOGRAPHY Joseph), to yellow (Hurwal Divide ) . T he more common less ~1mpetent rooks by shoving them aside and folding Many granodiorite outcrops have resisted the act ion coarse, granular and friable marble has indi vidual crys thern •till more. Thus the limestones were squeezed un of weathering agents for untold centuri es, The rock i s Location tals three .millimeters in diame te ~as in the areas of til they became semi-plastic and the enormous thicken formed principally of quartz, feldspar, black mica, and the Lostine, Hurricane, Wallowa, and :imnaha rivers. ing around the head of Lake and Hurricane Creeks was occasionally hornblende, of medium grain size. It pre The central portion of the Wallowa Mountains cov Argillaceous phases, grading into t he sediments, are not developed. The magma also advanced by stoping, as large sents a pleasing contrast, takes an excellent polish, and ered by the me.p is located in southern Wallowa County, oomnon. blocks of the sediments are found completely isolated tends to break into large blocks. At present much of t he extreme eastern extension of Union County, and a within the granitoid rock. This stoping or assimilation the better quality granodiorite is located unfavorably very small portion of Nort hern Baker County. It i n Well developed banding may be due to original bed was better developed in the southern portion of the for development. This situation vrill probably be remed cludes nortions ofT, 2, 3, 4, 5, & 6 S,, R, 43, 44, & ding but probably resulted from intense metamorphism. range where ~uch of the granite i tself eventually came ied in the near future when roads are constructed for 45 E., i n the extreme northeastern part of the State to be made of more or less dissolved sedimento, At no recreationnl purposes. Sills and ve i ns of i c;neous rock have of t en been brokon of Oregon. Its boundaries approximats those of the so and "stretched"; one occurrence gave conclusi~ evidence place, however, did the magma reach the surface, as of having Garnets for Abrasives called Ee. c le Cap Primitive Area in the Wallovra and Whit been "stretched" five timo s its original nearly as can be deternined front t he present record, length. The once plast a ro Q~ d man Na t ional Forests. It includes the drainage of Los ic marble flowed t he se ob Thi s r:agm.a. vm s probabll' a part of t he gr eat late structions as i ndicated by contorted, folded, and Jurassic or early Cretaceous granit e batholiths that The tactite developed a t the c rano d iorite-lime~ to n e tine River, Hurricane Creek , West and East Forks of contacts contains garnets that range from one-eighth t o Wallowa River squeezed banding. for:ned in the western Cordillera. on the north; and main Eagle Creek on one inch i n diarteter, and has a calcareous mat rix t l ·.a ~ the so•1th . is quit e Where t he marble has been intruded ily granitoid As the granodior i t e cooled and contracted, it frac soft. Garnets also ~orm solid ma sses up t o GO feet wide. rocks, a tactite zone is often developed that will range tured and permit ted numorous dikes of granodiorite Mining development along t he tactite zones might pernit the extraction o~ from one inch to tens of feet in width. The more com porphyry and aplite and l ru:tprophyre t o p enetrate its this garnet as an abras mon metamorphic minerals are grossulari te garnet, wolla upper portions and t he cover of older rocks as well. ive by-product material. stonite, and epidote, as well as quartz, molybdenite, some scheeli te, and secondary calcite, The contacts of This new mountain r ange was then exposed to the basalt dikes with marble are sharp and unmineralized. agents of weathering and erosion and the overlying, SUGGESTIONS TO PROSPECTORS highly folded rocks v;ere s t ripped away, exposi ng the Strati g raph~cally, the marbles can probably be cor grani te core. A rolling terrane developed, covered with r elated with the ": ·snow. T final de his snow was compact ed into ice and the ice grad cision is r..ade. Scheelite is difficult to identify b'y mounts ·of hornblende. Some phases range to muscovite ually moved down the alrea dy existing canyons. Soon the 1, i- quartz granite and even alaskite to dark colored diorite. "eye-ball assay" methods; it should be pulverized a':d I center of the range was covered by a great ice sheet. penned and The portions containing the greatest quartz appear to as the scheelite is heavier than quartz ~ t I I __L~ ____ ji- be Rocks and debris were carri ed along by the glaciers as will trail --'--- --t-----'-jij_.__ small intrusions separate from the main mass, as in B. the quartz mine'rals in the pan. A more sat E V • they gouged out their channels, giving the valleys a isfactory , •. T·-... -·h c. basin and above Lapover on Losti ne River. Aplite and and incidently more expensive, methQd i s t o characterist ic U-shaped profile, smoothing rook surfaces, use an ultra-violet pegmatite dikes were noted in several localities. Near lamp outfit. Light from t his i nstr u hollm•ing out the mult i t ude of basins now filled with ment causes the limestone contacts, tonalite phases appear. 1/ The scheelite to glow or fluoresce but i t m ust lakes, and sculpturing the pinnacles and spires of the be operated in total darkness. argillite end greenstone contacts with the granitoid highest The VlalloVla Valley is served by a branch of peaks. At the snouts of the glaciers which the rook are usually without contact metamorphic minerals pushed Union Pacific, LaGrande-Joseph branch, and by hard onto the level Wallmva valley, great piles of de Certain nonmetallics such as marble, Eranitc, and sur but considerable silicification frequently occurs. bris faced state highwa y 82. A Forest Servi ce road extends were stacked t o form the lateral and terminal mor carnet r.ta.y be developed as economic conditions j ustify . aines. up Los t ine River 18 miles south of the town of Lostine. Eventually the ice disappeared from all but one The "rospector shou.ld collect data and specimens of It is assumed that this grani toid rook is a part of side of Eagle Cap, and wa t er f i lled Good trails follow the east and west forks of Los t ine the i ce scoured bas th es~ mat eri als aGainst t he titr.e when t hey will beco•cc the Mesozoic batholith, probably upper Jurassic or lower ins to fo~ lakes. Los River to the Lakes Basin and t he summit of the range. t i ne Lake, whi ch formed behi nd its economically important. Cretaceous age. Erosion must have proceeded for some terminal moraine as Wallowa Lake Tl !I S formed, !lurricane Creek is reached from either Enterprise or ha·s been time before later basalt was poured out, as an old pre destroyed by the stream cutt ing out the morainal dam. Joseph; a Forest Service road penetrates the Wallov~ basalt surface has been identified. It is characterized Wallowa Lake remains, an unique feature of the glacial Na t ional Forest about two miles and an excellent trail by a deep granitic soil, with occasional gravel beds act ivity, and is naw protected by a man-made dam. SELECTED BIBLIOGRAPHY follows the creek to its headwa tars and into the Lakes composed of large boulders of quartzite, granite, ande Ba sin. Trails go up both forks of Wallowa River from site and other rocks. This terrane was gently rolling, Recent gaol ogy includes the unti ring vrork of the Wallowa Lake; the trail up West Fork goes to the Basin 1. ness, Fra~'l( L., and Larsen, Esper S., . "Contact l:~ta and represented a late mature stage of topography. streams to reduce canyons an and to the headwaters of Imnaha River, and the trail up d t he canyon walls to a morphic Tungsten Deposits of the Un1ted States : U. general flat plain. Much of the glacial debris rAS East Fork passes Aneroid Lake and continues southeast Dikes s. Geol. Survey , Bull. 725-D, PP• 308-309, 1921. across t he Imnaha River to Cornucopia. been reworked by these st reams. 2. Rodge, Edwin T., "l.!arket for Columbia River F.ydro eleotrio Dark-colored dikes, the so-called "iron dikes", are Pavrer Using NortlnEastern Oregon": U. S. Geol. S~rvey, Bull 87 5, passing through the granodi orite into and through the The most favorable develooment of economic minerals Aside from the trails mentioned, there are few sec Oe.salt flows. pu. 119-132, 1937 . ondary trails or ways. Some lines of travel have been usually occurs at or near granodiorit e-limestone con 4. Parks, lienry, "Preliminary Report on Suildinc Stone blazed by fishermen but for the most part it is a case tacts i n a tacti te zone, particularly where li.Jnestone In Ore g on~: Cree . Bur. l.!ines & Geol., v. 1, no. 2, Many dikes that appear to be basaltic are more pro ov~rlies ~ ranodiorite. The economic minerals are there of "follow your nose". perly classed as l~~prophyric phases (complimentery dikes) PP• 30-35, 1914. fore of t he contact-metamor phic type, of which molybden 5, Ross, Clyde, "Geology of of the granodiorite intrusion. One of these occurs just a Part of t he Wall?'"!': .~:!o u n ite is of principal importance. tsins, Oregon": Orei; • State Dept. Geol. ,., ..1n er :>. l above Aneroid Lake. These dark-colored dikes are mapped Indnstries, Bull. no. 3, 74 ?P•• 1938. as undifferentiated. J,:Sj The area has an average relief of 3000 feet and or fracture zones are also r.ineralized to a cer G. Snit h , ;·jarren Du Pre, "Ph;rsical and Lcono!:lic Geocra?hY tain extent, as the La paver-Franci s Lake-Twin Peaks zone . of' Orecon, Chap XI I I, Tfte Yfallowa h~o untains and elevations rang ing from 4500 feet to 10,000 feet. Hill The dikes are most frequently seen in areas of County": ~Or.'J:! O!n'!eal t h Review of Uni ver s .L t y of side slooes of 300 are common, and the north-south granitoid rocks, where they are occasionally three miles O r ~:; . , Mineralization is also associ ated with sone of the ~ .s., v. 10 , ~ o. 4, pp. 159-194, 192 r i dges ~e fairly continuous. The late-youth t opography long . Thickness varies from a few inches to 40 or 50 8. lampr t> phyric dikes. There are t hr ee general syster.s of 7. Swa rt ley , Arthur I-:., "Ore l)epos i ts of N ort is extensively mod i fied by Pleistocene and Recent glacia feet, with 20 feet being the more common. The trend is ~ oastern dikes: an aplitic sy s t em with no associated mineraliza Or er::;or.. ": Or es . Bur. ?-!ines t: tion. from 10° to 30° northwest in the Lostine River drainage Gc ol., v. 1, no. 31 tion and little contact -mctanorph ism; a lamp rophyr i c ?~ · 57-96 , 116-113, 1914. and in the Lakes Basin; nearly north-south in the liurri system that l'lay have followed t he apli tes l':ith soMe mir.. cane and Wallowa drainage; and in three directions in ere. l ization; a !:luch l ater basal t in system with r..o niner the ~ain Eagle drainage. The dips are almost vertical. GEO LOGY AND ST:aATIGRAPHY alizat ion and pr actically no cont act -metamorphism. No mi neralization along the contacts of the basalt The following determinations and correlations are ic di kes with intruded rooks was noted. In fact, the based on field methods and are tentative, subject to contact is exceptionally sharp, as if the injected liq Gold and silver, i n conr.e rcial quant ities, have correction when laboratory work is completed on the uid was at low temperature and exerted little pressure rocks and fossils collected. A more detailed never been re covered wit l: in t he area na p?ed so far as is descrip during its intrusion. Many of the lamprophyrio ( ?) knovm. S:na ll amou nt s ar e r eport t ion of the area will be published by this Department ed fron some of the pros dikes appear to have sharp contacts wi th little evidence pects visited '\"the r e most of the d evelopnent wor k has been as Bulletin ~o. 12, of which this map i s a part. of c ontact metamorphism, but further st udy is needed. for copper. Such or es nay car ry goln val ue s that will te