Lava cascade in Thunderbolt Distributary of Labyrinth Cave system
report report
Ovis Cave Apparently, E.L. Hopkins was the first white visitor to Ovis Cave (map 4, pl. 2) in the 1890's. He reported finding 36 Bighorn sheep skulls in the cave (fig. 27). J.D. Howard explored this area in 1918 and named the cave Ovis, the Latin word for sheep, although by this time Bighorn (Ovis canadensis) had disappeared in this part of the West. Ovis Cave resembles a huge railroad tunnel 200 ft long, 20--40 ft high, and 30-50 ft wide (fig. 28). When it was formed, its floor was 60ft or more below the surface. Angular blocks that tumbled from the ceiling buried its floor beneath rubble. Original ceiling features such as lavacicles can be found only on the fallen blocks. Patches of accretionary wall lining, however, have remained intact over half of the original walls. Seven narrow lava balconies indicate that lava flowed at each of these levels long enough to solidify and leave easily traceable ledges. Many of these nearly horizontal ledges resemble continuations of flow layers. This tube developed within a lava pile composed of different flow layers. Contacts between these layers, as seen in the walls of the tube, were plastered over by lava that later drained away. Figure 27. Skulls of Bighorn sheep were found in Ovis Cave (see fig. 14 and map 4, pl. 2), giving the cave its name. Figure 28. Entrance of Ovis Cave (see fig. 14 and map 4, pl. 2) as seen from inside this large feeder tube. Person at left for scale. 30 Selected Caves and lava-Tube Systems, lava Beds National Monument, California
Deep collapse trenches terminate Ovis Cave at either end. They mark positions along a system of large lava tubes at least 6 mi long, which extends from Mammoth Crater (fig. 4) to beyond Post Office Cave. This system of tubes may extend to Craig Cave and beyond. Paradise Alleys The intertwining tubes of the Paradise Alleys can, for convenience, be divided into three levels (map 4, pl. 2), although most of the upper level is only a partially developed drained balcony within the middle level. Lower Level High on the east wall of Ovis Cave, just below the roof and near the collapse that terminates the cave's extension to the south, a small lava tube branches off. This small eastern distributary hangs 25 ft above the rubble-covered floor of Ovis Cave and is the head of the lowest and probably oldest level in the Paradise Alleys distributary system. Within 20 ft of its beginning, however, the floor of this tube is left hanging as a balcony on the walls of a second and slightly larger tube. This tube trends northeast from its head on the north wall of an east-trending shallow basin, which branches from the main collapse trench to a point 40 ft east of the head of Ovis Cave (map 4, pl. 2). After they join, both the balcony and the floor of the tube below it tum to the northeast in a series of lava cascades. They pass completely beneath the much wider middle level of Paradise Alleys. The middle level originated and flowed north from the east end of the shallow collapse basin. Most of the accessible length of the lower-level tube shows lavacicles and dripstone walls whereas its original pahoehoe floor is littered with collapse blocks. Downstream 70 ft below this passage's entrance, a 6-ft-diameter rafted block half-closes the tube. The upper surface of this rafted block is decorated by many broken and distorted lavacicles and by lava, which coated it during its transit along the tube. Downstream 180 ft farther from the entrance is a hole in the left (west) wall of the lower level tube, 10 ft above its floor, which provides ladder access to the middle level of Paradise Alleys. From here visitors can leave via the Paradise Alleys entrance, another 80 ft downstream. Downstream 45 ft from the foot of the ladder, the lower-level tube is blocked to further entry by a roof collapse. Middle Level Of these three tubes, the 40-ft-wide middle-level passage is the largest and transmitted the most lava. Only 240ft of its length is accessible because its continuation downstream below the Paradise Alleys entrance is completely buried by collapse debris. Unquestionably it extended beneath the partly collapsed skylight just to the east, and from there it extended beneath the upper level to a subterranean junction with the lava lake that once filled the Catacombs Basin. Upper Level The upper level of the Paradise Alleys tubes begins as a balcony hanging on the east wall of the middle level tube 80 ft upstream from the Paradise Alleys entrance. Here, its rounded upstream end can be entered by climbing a 5-ft ladder. Whereas the middle-level tube bends almost 90° at the entrance to Paradise Alleys, this adjacent upper-level tube continues straight as a smaller tube. From the entrance alcove one can walk downstream for 75 ft to where the tube emerges into a former skylight whose walls have been greatly enlarged by late-stage collapse. As the upper level leaves this skylight downstream, however, the tube changes drastically in character. It becomes larger, 25-40 ft wide, and much of it-especially to the northeast-appears to be filled almost to the roof with lava. Moreover, much of its pooled lava floor has collapsed (fig. 29) into a lower tube. This is best shown by a traverse upstream beginning from its northeast end, where lava fill reaches the roof and blocks access to the northeast; here a jumbled mass of floor blocks lies just below small balcony remnants still attached to the walls. On the left (northwest) wall a huge 30-ft slab of the balcony is detached from the wall and now lies on its side atop fractured blocks of the subsided floor. Another 80 ft upstream where the ceiling is lower, a remnant of balcony crosses the tube and Figure 29. Original pahoehoe floor of upper level Paradise Alleys tube (see fig. 14 and map 4, pl. 2) collapsed when molten lava withdrew underneath chilled surface. Ovis Cave and Paradise Alleys 31
- Page 2 and 3: Lava cascade in Thunderbolt Distrib
- Page 4 and 5: Frontispiece. Two visitors explore
- Page 6 and 7: DEPARTMENT OF THE INTERIOR MANUEL L
- Page 8 and 9: Caves easily accessible from Cave L
- Page 10 and 11: PLATES [In pocket] 1. Caves of the
- Page 12 and 13: Many of the feature names used in t
- Page 14 and 15: Tulelake LOWER KLAMATH LAKE Prisone
- Page 16 and 17: EXPLANATION ................... Lav
- Page 18 and 19: flow, then the lava may pool behind
- Page 20 and 21: "pull outs" where the dripping plas
- Page 22 and 23: Mushpot, Catacombs, Ovis, and Merri
- Page 24 and 25: Waters agreed to do the cave mappin
- Page 26 and 27: into the distributary in the genera
- Page 28 and 29: crawled 180 ft from the Mushpot tub
- Page 30 and 31: es of plaster clog its continuation
- Page 32 and 33: level of the tube. The southern ent
- Page 34 and 35: surface collapse and only one comer
- Page 36 and 37: dead-end passages on different vert
- Page 38 and 39: and a roof covered with lavacicles
- Page 40 and 41: puzzles abound in the Catacombs; do
- Page 44 and 45: thus forms a bridge over the broken
- Page 46 and 47: pit is located along the southwest
- Page 48 and 49: lava tubes, and the upper parts of
- Page 50 and 51: occupies the lava pool just upstrea
- Page 52 and 53: underway. Collapse to the surface h
- Page 54 and 55: one located just below ceiling heig
- Page 56 and 57: high, but it immediately widens to
- Page 58 and 59: low depths along fissures. Many sma
- Page 60 and 61: collapse (map 9, pl. 3). Two others
- Page 62 and 63: For a short distance below the coll
- Page 64 and 65: circle the two large downstream pil
- Page 66 and 67: where it opens into the north end o
- Page 68 and 69: water well, the cave changes marked
- Page 70 and 71: the older Schonchin Butte lava flow
- Page 72 and 73: here to the entrance, the tube is f
- Page 74 and 75: One cannot walk beneath it, as unde
- Page 76 and 77: Room-is actually a natural bridge,
- Page 78 and 79: pooled in the mouth ofthe tributary
- Page 80 and 81: perfection and cleanliness of its l
- Page 82 and 83: etween the benches. The levees are
- Page 84 and 85: tubes created a cave floor that is
- Page 86 and 87: cessive accretionary linings of lav
- Page 88 and 89: two levels were joined by a breakdo
- Page 90 and 91: ft and passes through several level
Ovis <strong>Cave</strong><br />
Apparently, E.L. Hopk<strong>in</strong>s was the<br />
first white visitor to Ovis <strong>Cave</strong> (map 4,<br />
pl. 2) <strong>in</strong> the 1890's. He reported f<strong>in</strong>d<strong>in</strong>g<br />
36 Bighorn sheep skulls <strong>in</strong> the cave (fig.<br />
27). J.D. Howard explored this area <strong>in</strong><br />
1918 and named the cave Ovis, the Lat<strong>in</strong><br />
word for sheep, although by this time<br />
Bighorn (Ovis canadensis) had disappeared<br />
<strong>in</strong> this part <strong>of</strong> the West.<br />
Ovis <strong>Cave</strong> resembles a huge railroad<br />
tunnel 200 ft long, 20--40 ft high, and<br />
30-50 ft wide (fig. 28). When it was<br />
formed, its floor was 60ft or more below<br />
the surface. Angular blocks that tumbled<br />
from the ceil<strong>in</strong>g buried its floor beneath<br />
rubble. Orig<strong>in</strong>al ceil<strong>in</strong>g features such as<br />
lavacicles can be found only on the fallen<br />
blocks. Patches <strong>of</strong> accretionary wall l<strong>in</strong><strong>in</strong>g,<br />
however, have rema<strong>in</strong>ed <strong>in</strong>tact over<br />
half <strong>of</strong> the orig<strong>in</strong>al walls. Seven narrow<br />
lava balconies <strong>in</strong>dicate that lava flowed<br />
at each <strong>of</strong> these levels long enough to<br />
solidify and leave easily traceable ledges.<br />
Many <strong>of</strong> these nearly horizontal<br />
ledges resemble cont<strong>in</strong>uations <strong>of</strong> flow<br />
layers. This tube developed with<strong>in</strong> a lava<br />
pile composed <strong>of</strong> different flow layers.<br />
Contacts between these layers, as seen <strong>in</strong><br />
the walls <strong>of</strong> the tube, were plastered over<br />
by lava that later dra<strong>in</strong>ed away.<br />
Figure 27. Skulls <strong>of</strong> Bighorn sheep were<br />
found <strong>in</strong> Ovis <strong>Cave</strong> (see fig. 14 and map<br />
4, pl. 2), giv<strong>in</strong>g the cave its name.<br />
Figure 28. Entrance <strong>of</strong> Ovis <strong>Cave</strong> (see fig. 14 and map 4, pl. 2) as seen from <strong>in</strong>side this large feeder tube. Person at left for<br />
scale.<br />
30 Selected <strong>Cave</strong>s and lava-Tube Systems, lava Beds National Monument, California
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