Lava cascade in Thunderbolt Distributary of Labyrinth Cave system

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EXPLANATION ................... Lava tube • Cave Paved road \J ~ \I ~ ,= Tule Lake National Wildlife Refuge %,~ ~ \Q.. I TuleLake Captain Jacks Stronghold Fern Cave • Approximate boundary of Lava Beds National Monument Juniper_ Butte Q • Crai~ Cave and I Craig TTple Basalt of Valentine Cave 0 CONTOUR INTERVAL 200 FEET 4 Selected Caves and Lava-Tube Systems, Lava Beds National Monument, California
over a lava fall or down a series of lava cascades. Two additional varieties of pahoehoe are commonly recorded by observers of actively erupting flows in Hawaii but are more difficult to recognize in the congealed flows at Lava Beds National Monument. Pahoehoe toes from 1 to several feet in length may sprout forward all along the front of some advancing lava flows. In places the chief manner of forward movement is by the extending and overriding of successive pahoehoe toes. Shelly pahoehoe congeals where large hollow lava blisters 3 ft or more in diameter have formed beneath a thin crust of erupting volatile-rich lava. These large lava blisters flow out, flatten, and override one another. Fleener Chimneys, in the monument, erupted shelly pahoehoe as the last part of the eruption that produced the Devils Homestead flow. Much of this flow is aa (fig. 7), particularly farther from the vents at Fleener Chimneys. The bubbles and blisters that form in molten lava are produced by release of water and other gases from the molten rock. When pressure is lowered by rise of molten liquid, called magma, to the surface, or by the turbulence of tumbling over a cascade, the lava may froth just as the dissolved carbon dioxide in beer will froth and form bubbles as you open the can and tumble the beer into a glass. Not all collapses of lava-tube roofs took place after volcanism ceased. Many lava tubes contain easily decipherable records of breakdown that occurred when molten lava was flowing through a tube. Careful examination of the congealed surface of the last flow of lava down a tube is likely to reveal both small and large blocks of rock that tumbled from the roof of the cave and were then rafted downstream on the molten flood until it, in turn, congealed into rock. Large rafted blocks are shown on the maps of this report . If a large segment of a tube roof collapses while the tube is still filled or half-filled with flowing lava, a number of events can occur that leave their record in the rocks to be examined long after volcanism ceased. If the tube is only half full of flowing lava, and the thickness of collapse debris is nearly equal to the Figure 5. Ropy pahoehoe. A pasty redhot rind of partly congealed magma at the surface of a lava flow was folded and twisted into rope-like ridges as it was dragged forward by the molten rock beneath. Chilled by air, the lava surface congealed into lustrous black glass. Near Giant Crater, south flank of Medicine Lake volcano (see fig. 1 ). Pahoehoe • Spiny • pahoehoe A a Figure 6. Increasing vesiculation and turbulence may cause a lava flow to change from pahoehoe to aa downstream. .... Figure 4. Location map of Lava Beds National Monument showing major lava-tube systems, cave locations, and other selected features. Basalt of Mammoth Crater shown in blue. Other lava flows shown in red. Figure 7. Example of aa lava, broken surface of Devils Homestead lava flow (see fig. 4). Introduction 5
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 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 42 and 43: Ovis Cave Apparently, E.L. Hopkins
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
Page 92 and 93:
stream, the ceiling heights drop, t
Page 94 and 95:
Cave. Collapse rubble half fills Cr
Page 96 and 97:
heights are between 12 and 20 ft in
Page 98 and 99:
Blue Glacier Room, where continuati
Page 100 and 101:
upstream from the one noted by the
Page 102 and 103:
Red Ice Room (fig. 63), which lies
Page 104 and 105:
tation that this tube system was fe
Page 106 and 107:
sured ground now occupies nearly tw
Page 108 and 109:
The larger and more interesting cav
Page 110 and 111:
part talus was reversed. Moreover,
Page 112 and 113:
long and 300ft in maximum width. Th
Page 114:
and lunar implications: Communicati
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Lava cascade in Thunderbolt Distributary of Labyrinth Cave system

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