BULLETIN 88 GEOLOGY AND MINERAL RESOURCES OF THE UPPER CHETCO DRAINAGE AREA, OREGON INCLUDING THE KALMIOPSIS WILDERNESS AND BIG CRAGGI ES BOTANICAL AREAS STATE OF OREGON DEPARTMENT OF' GEOLOGV AND MINERAL INDUSTRIES R E. CORCORAN. STATE GEOLOGIST 1975 STATE OF OREGON DEPARTMENT OF GEOLOGY AND MINERAL INDUSTRIES 1li69 State Office Bui I ding, Portland, Oregon 97201 BULLETIN 88 GEOLO GY AND MIN ERAL RESOURC ES OF TH E UPPER CH E TCO DRAINAGE AREA, ORE GON INCLUDING THE KALMIOPSIS WILDERNESS AND BIG CRAGGIES BOTANICAL AREAS Len Ramp, Economic Geologist Oregon Department of Geology and Mineral Industries GOVERNING BOARD STATE GEOLOGIST R. W. deWeese, Chairman, Portland R • E. Corcoran Leeanne MacColl Portland H . Lyle Van Gordon Grants Pass 1975 FOREWORD Mining and agriculture are the primary sources of all new wealth , and minera ls are th e lifeblood of any industrialized civilization . Annua lly the economy of the Uni ted States now requires more than four bi Ilion tons of new minera l supplies. Two decades ago that tonnage was only half as large, whereas by the year 2000 it could nearly triple present requirements. Development of domestic minera l resources is not keeping pace with domes­ tic demand . Ever-increasing mineral imports are producing a continuing unfavorable U.S . balance of trade, and expropriations of mines by foreign governments have modifi ed th e flow of these materials to th is country or made th em more costly. The area designated as the Ka lmiopsis Wil derness has had a his­ tory of sporadic mining activity dating back more than 100 years . Gold mining, both lode and placer, and chromite mining have been carried on in relatively recent times . Know n deposits of iron, copper, and nickel are now attracting the interest of prospectors and mining companies . The approximately 80,000 acres of land included in the Kalmiopsis Wilderness will be closed to mineral entry on December 31, 1983. The purpose of this report, therefore, is to provide basic geologic information on th is large mineralized region so that th ere will be an available record of th e mineral potential for future use. If the United States is to maintain a reasonable self-sufficiency in its minera l requirements, the mining indus­ try wi II need to accelerate its domestic mineral exp loration programs dur­ ing the coming years . It is hoped that this bu l letin will help to expedite the efforts by the private sector to find and develop some of the known mineral deposits in this part of southwestern Oregon before they are locked up. R. E. Corcoran State Geologist September 1975 iii CONTENTS FOREWORD - -- ----------------------------------- iii INTRODUCTION ------------------------- - --------­ 1 Location of area - - - - - - --- - - - - - - - ---- - - - - - - --- - - - 1 Purpose and scope of study - - - - - - - - ----- - - - - - - - - - --- - 1 Field methods --------- ------------------------- 3 Previ ous work ---------------------------------­ 3 Access to area - ----- ---- ---------- ----- -- ----- -- 3 Ac know I edgm ents - ------- --- - ---- -- ----- --- --- --- 4 TOPOGRAPHY, CLIMATE, AND VEGETATION - ------------ -- 5 GEOLOGY - - - ---- ---- - - --- --- ------------ - ---- - - 8 Genera l discussion ----------------------- -------- 8 Pre-Tertiary rocks -------------------------------­ 8 Amphibole gneiss and s chist - - --------------- -----­ 8 Rogue Formation ----------------------------­ 9 Ultramafic rocks --------------------------- -­ 9 Pyroxenite and coarse-grained hornblendic rocks --------­ 11 Gabbro, gabbro diorite, and metagabbro -------------­ 11 Diabasic and related dikes ----------------------­ 13 Diorite dikes and related rocks and pegmatites ------ ---­ 13 Dothan Formation - -------------------------- -- 1 5 Tertiary and Quaternary rocks ------------ -- ---------­ 1 5 Dacitic dikes ------------------------------- ­ 15 Old s tream gravels ---------------------------­ 1 7 Glacial moraine - ---------------------------- 1 7 Bench gravels -------- ------ ---- -------- ---- -- 1 7 Landslide debris --------- ------- -------------- 17 Structure -------------- - -------- ------------- 19 -- Thrust fau Its ------ -- -- ---- -- -- -- -..., ------- - 19 Folds ---- - - - --- ---- - ----- - --- ----- - ------ 21 HISTORY OF MINI NG ACTIVITY --------------------- --­ 22 Production of gold ----------- --------------- -----­ 22 Production of chromite ------------------------- --- 23 Production of other minera ls 23 METALLIC MINERAL RESOURCES 24 Chromite ---------------------------------- ---­ 24 Coba lt ------------------------ -------------­ 24 Copp� ------ - ----- ---------- ---- ------------ 27 Gold ----------------- - ______________________ 29 Iron 35 Manganese -------- -- -- -----------------------­ 35 M�c�y ------------------------ -------------­ 37 Nickel -------------------------------------­ 37 Platinum ------------- - - --------- - ------ --- ---- 40 iv ---------- -- I N --------- --- -- NDUSTRIAL MI ERALS - - - - 40 -- ----- ------- BIBLIOGRAPHY - - - --------------- --- 41 APPENDI XA. Geochemica lresu lts of stream -sediment sam ples --- - - 43 APPENDIX B. Thi n sections of rocks - --------------- ----- - - 47 IL LUSTRATIONS Figures 1 . Map of southwest Oregon showi ng extent of study area and access routes - - ------ ------ 2 2. Em ily Cabin, hom e of Perry and Ruth Davis, is a historic site near the Li ttle Chetco River --- 4 3. Viewwest across southern part of Kalmiopsis Wilderness Area ----- - -- - ------ ------ 6 4. Pearsoll Peak lookout station. The peak i s highest point in study area. ----------- ---- 6 5. Vulcan Lake, larger and higher of two glacial cirque lakes at head of Box Canyon Creek --- - 7 6. Viewacr oss Vulcan Lake from east shore - ----------- - - ----- ----- - --- - ------ 7 7. Overturned tuffaceous sedimentary rocks and interbedded vo lcanics of Rogue Formation 10 8. Gritty sands tone layer in Rogue Formation exposed on Babyfoot Creek -- --- ------ -----1 0 - 9. A step in the formation of coarse-grained hornblendic metapyroxenite - - - - - ---------- 12 10. Coarse-grained hornblendic meta pyroxenite exposed on ridge; crystals up to 2 feet long - --- 12 11. Coarse-grained hornblende gabbro in Little Chetco River illustrates pecu liar comb texture --- 14 1 2 . Augen gneiss (gneissic metagabbro) of B ig Craggies illustrates ptygmatic folding and textures - 1 4 1 3. Clinopyroxene crysta I inc Iusion in Big Craggies gneissic metagabbro - -- -- -- -- ---- --- - 16 14. D iori te dikes penetrating gabbro are exposed on ri dge - --- ---- ------------ - -- --- 16 15. Crest of plunging asymmetric fo ld in Dothan Formation exposed on Chetco River --- ---- -- 1 8 16. Bench gravel on upper Chetco River near Madstone Cabin site -------- ------------- 18 17. Valen Lake was form ed by a rock s lide off a steep face of Dry Butte, wh ich dammed creek --- 20 18. Ultramafic landslide breccia exposed above southwest part of Sourdough Flat ------------ 20 19. Old placer workings ("China Diggins") in bench gravel of Little Chetco River - ------- - - 21 20. Ruins of mill at Hustis mine - - ------------- -- -------- - - ------ --------- - 22 21 . Open pi t at Gardner chrome mine - ---- -------------- -- - - ---- -- ------ ---- 26 22. Magnetite clots in altered pyroxenite - --- -- -- ------- --- ---------- --- ----- 26 23. Auger sampling nickel -bearing lateritic soil on ridge northwest of Hawks Rest ----------- 38 24 . Sketch map of Sourdough nickel prospect , Curry County - ---- ------ -------- - ----- 39 Tables 1. Chrom ite occurrences in the upper Chetco River area --- - - - --- --- - - - - ------- - - -- 25 2. Copper prospects and occurrences , upper Chetco River area -------- - - ----- ----- - - 28 Maps in pocket Geo logic map of the upper Chetco drainage area, Curry and Josephine Counties Minera l -localities and sample-sites map, upper Chetco drainage area, Curry and Josephine Counties v GEOLO GY AND MI NERAL RESOURCES OF TH E UPPER CHETC O DRAINAGE AREA , OREGON INCLUDING THE KALMIOPSIS WILDERNESS AND BIG CRAGGIES BOTAN ICAL AREAS INTRODUCT ION Location of Area The Upper Chetco River drainage area lies in the Klamath Mountains geomorphic province of southwestern Oregon . The map area is situated mainly in Curry County , but its eastern and northern margins extend into adjacent Josephine County (Figure 1). Within the map area, and occupying most of it, is the Kalmiopsis Wilderness Area; to the northwest is a portion of the Big Craggies Botanical Area. The Kalmiopsis Wilderness Area (formerly designated a Wild Area) was established by Congress as part of the National Wilderness System in 1964. It includes approximate ly 76, 900 acres and is subject to the regulations defined in Public Law 88-577 of Sept. 3, 1964. Prospecting is allowed and mining claims may be located on valid mineral discoveries in the area up to, but not after, December 31, 1983 . On January 1, 1984 mineral resources , subject to valid existing rights, are withdrawn from all forms of appropriation under the mining laws within wilderness areas designated by this Act. The Kalmiopsis Wilderness Area is roughly oval in shape . The eastern and southern boundaries are established approximately a long the drainage divide between the Chetco and Illinois Rivers and the Chetco and North Fork Smith Rivers. The southwestern and western boundaries are at Red Mountain, Vulcan Peak, Moores Ridge, Quail Prairie Mountain, and at the mouth of Boulder Creek on the Chetco River. The boundary then fo llows along the Chetco River and up Tincu p Creek to Pearsoll Peak on the north.