STATE OF OREGON

1 STATE OF OREGON . DEPARTMENT OF GEOLOGY AND MINERAL INDUSTRIES. 1069 S tate Office Building Portland, OREGON 97201. BU L LETI N 71. GEOLOGY OF SELECTED LAVA TUBES IN THE BEND AREA, OREGON . By Ronald Greeley Space Sciences Division National Aeronautics and Space Administration Moffett Field, California 1971. GOVERNING BOARD. Fayette I. Bristol, Rogue River, Chairman R. W. deWeese, Portland Harold Banta, Baker STATE GEOLOGIST. R. E. Corcoran FOREWORD. OREGON probably has the greatest diversity of volcanic rock types and landforms of any region in the conterminous United states .

2 The area centering around Bend has come to be known as OREGON 's "moon country" because the very young volcanic rocks in this vicinity show features similar to what have been photographed on the lunar surface. The National Aeronautics and Space Administration has, therefore, spent considerable time studying various aspects of the terrain in central OREGON because its scientists have interpreted certain lunar forms, such as the sinuous rilles, as volcanic structures. Mr. Ronald Greeley, the author of this report, believes that some of the smaller lunar rilles probably resuIted from I ova-tube coli apse.

3 Up to the present time, there has been relatively little study of lava tubes in the western United states to determine their origin, nor have these unusual structures been described in sufficient detail to be classified into different types. Mr. Greeley has selected several lava tubes in the Bend area for such a study because of their excellent development and relative ease of access. The Department presents this publication with the hope that it will stimulate the interest of others in exploring the many unusual and fascinating geologic features that occur in our "moon country.

4 ". R. E. Corcoran OREGON STATE Geologist ii C O N TENTS. Page -1- Abstract . Introduction Field methods 3. Geology and physiography 3. Lava tube formation . 5. Lava tube descriptions 12. Arnold Lava Tube System 12. Upper section . 12. Charcoal Cave 12. Arnold Ice Cave 15. Middle section 15. Collapsed Lava Pond No. 15. Deg Cave 18. Bat Cave 18. Lower section . 18. Wind Cave 18. CoIIapsed Lava Pond No. 2 22. Pictograph Cave 22. Coli apsed Lava Pond No. 3 24. Charcoal Cave No. 2 . 24. Collapsed Lava Pond No. 4 24. Stookey Ranch Cave 27.

5 Collapsed Lava Pond No. 5 27. Horse Lava Tube System 27. Lewis Farm Caves 27. Garbage Caves 31. Gar bage Cave No. 2 31. Stevens Road Cave 31. Horse Cave 31. Wilson Cave 31. Barlow Cave 31. iii Page Miscellaneous lava tubes . 33. Lava Top Butte Caves 33. Log Crib Cave 33. South Ice Cave 34. Skeleton Cave 34. Boyd Cave 36. Lava River Cave . 40. Conclusions 45. Acknowledgments 45. References cited 46. Appendix (location of surveyed lava tubes near Bend) 47. iv I L L U S T R A T IO N S. F ig ures Pag e l. Mar i us H i l l s reg i o n of th e Moon.

6 Structure i nterprete d to be a par t l y c o l l apse d l ava t u be 2. 2. Loc a t i o n map a n d ph ys i ogr a ph y of c e n t r a l OREGON showi ng area of i nv es t i g a t i on near Ben d 4. 3. D i ag r a m of a m i nor l av a t u be system i n north ern C a l i forn i a 6. 4a. Bear Trap Lav a Tube , Idah o , showi ng l ayered l ava 7. 4b. Jug C av e , Wash i ng ton, sh owi ng l ay e r e d l av a 7. 5. W i nd Cave sh o wi ng f l ow l i nes a n d c ut ban k a t meander ben d 8. 6. R i m of c o l l a pse p i t , Bar l ow Cave , sh owi n g p l ast i c defor m a t i o n of l ava c r u st 10.

7 7. Boyd Cave Lav a Tu be sh ow i ng sand a t sur fa c e dra i n i ng i n to t u be 11. 8. Boyd Cave Lav a Tu be sh owi ng san d dra i ni n g through roof frac tur e 11. 9. Map of Ar no l d Lav a Tu be S ystem . 13. 1 0 . Obl i que a e r i a l v i ew of upper Ar no l d Lava Tu be System 14. 11 . Ar no l d I c e Cave near e n t r a n c e 16. 1 2 . Ar no l d Lava Tube System; cross s ec t i on s transverse to l av a tu be axi s ;7. 1 3. Di ag rams of c o l l apse l ava ponds of Ar no l d Lava Tu be System . 17. 14. Bat C av e sh owi ng p l as t i c a l l y deformed l i ni ng cu r l i ng from wa l l 19.

8 15. W i nd C ave sh ow i ng p l a st i c deformat ion o f w a l l l i n i ng 21. 16. E n tr a nc e to P i c tograph Cave . 23. 17. En tra n c e to P i c tog r a ph Cave showi n g poss i bl e g as poc ket 23. 18. P i c tograph Cave downtube from e ntra nc e 25. 19. Ob l i qu e a er i a l v i ew of Co l l apsed Lava Ponds No . 3 a n d No . 4 26. 20 . Map of Horse Lav a Tu be Syste m . 28. 21. Di ag r a ms of Le wi s Farm Cave, Horse Lava T u be System 29. v Page 22. Diagrams of Garbage C aves Nos . I and 2, Horse Lava Tube System 30.

9 23. D i agrams of Horse C av e , Horse Lava Tube S ystem 32. 24. South Ic e C a v e v i ewed toward e n tr a n c e 35. 25. D i ag r a m o f South I c e C av e 37. 26. S ke l eton Cave In ter i or . 37. 27. P l a n i metr i c di ag ram of Lav a R i v e r C av e 38. 28. Long i tudi n a l profi l e of Lava R i v er C av e 39. 29. Lava R i v er Cave near e n t r a n c e . 41. 30 . Lava R i v er C ave i nteri or sh owi ng r oof c ol l apse a n d mul ti p l e fl ow l i n e s on wa l l s 42. 31. Lava River Cave i nt er i or part l y fi l l e d wi th san d 42.

10 32. Lava R i v er Cave i n terior at th e S a n d Gar dens 43. 33. Lava R i v er Cave i n ter i or c ross sec ti on 44. P l ates (fo l d-outs a t end of bul l e t i n ). 1. Ar n ol d Lav a T ube S yste m 2. S e l ec te d l av a t u bes n ear Be n d, Oreg on 3. Ph otog e ol og i c map of th e l av a tubes of parts of Ben d a n d Newberry 30 ' quadr an g l e s, Orego n VI. GEOLOGY OF SELECTED LAVA TUBES IN THE BEND AREA, OREGON . by Ro n a l d Gre e l ey AB S T R AC T. L ava tube s i n the vi c i n i ty o f Be n d, OREGON , we re m apped and st ud ied i n deta i l to determ i ne the i r geomorp hol ogy a n d mode o f format io n.