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Spattercone Trail Spattercone Self-Guided Trail 1 LONG RIVER OF LAVA Welcome to You are standing on the edge of the Hat Creek Lava Spattercone Flow. About 20,000 - 30,000 years ago, large vol- Trail. This 1.5 umes of fluid lava poured from a series of fissures mile loop trail (cracks in the earth) and flowed northward for 16 will take you miles, covering the floor of the Hat Creek Valley. to the origin of The spatter cones, further up the trail, mark the the recent Hat approximate locations of these fissures. Creek Lava Flow, an area ROCKS WITH HOLES with many 2 spattercones The rocks here and and associated all along the trail are volcanic fea- basalt, a fine grained tures. dark volcanic rock Some portions of the trail are steep. Due to hot, rich in iron and dry conditions, it is best to take this hike in the magnesium early morning or late afternoon. Carry water ! Notice the small holes in the rocks. This particular kind of rock is called vesicular basalt (from the Latin CAUTION vesicular or “little bladder”), because of the small Stay on maintained trails! Some of the rock holes. outcroppings and cave ins are unstable and During solidification, trapped gas bubbles expand dangerous ! within the lava and escape into the atmosphere, leaving behind the small holes or cavities (vesicles). 3 POLLUTION INDICATORS Look closely at these rocks; can you see any small, crusty green, grey and orange specs or blotches ? These are lichens - a type of fungus that grows in combination with algae, forming the small organ- isms that you see here. The bright yellowish-green growth that you see on nearby trees is a larger lichen called Staghorn Li- chen. Lichens are sensitive to air pollution and are usu- ally not found where air pollution levels are high. Some lichen species are even used to monitor changes in air quality. Based on what you observe about the lichen here, do you think the air here is fairly clean ? United States Pacific Department of Southwest Lassen National Forest Agriculture Region Hat Creek Ranger District Greenleaf Manzanita can be WHO LIVES HERE ? identified by its roundish, 4 leathery, bright-green leaves and its smooth, reddish bark. Have you noticed any Manzanita seeds were used by wildlife along the trail ? local Atsugewi Indians to make Birds commonly seen flour. Ripe, red berries were along the trail include Greenleaf Manzanita Arctosopylus patula eaten as a fruit, while unripe, Ravens, Steller’s Jays, green berries were used to Red-tailed Hawks, and make tea and cider. Rufous-sided Towhees. HOLLOW WORLDS You’ll be crossing the Pacific Crest Trail as you go 7 straight ahead. After crossing, go left at the trail fork. As the lava flowed down- hill it devel- PUZZLE ROCK oped many 5 fingers that Lava from the Hat soon crusted Creek Flow was very over, restrict- hot (about 2000 degrees ing the inner F) when it poured out flow to a of the fissures. Fast hot “tunnel sys- flows such as this one tem”. are called Pahoehoe (Hawaiian word), As the inner liquid lava continued its course down- pronounced pah-hoy- hill, it sometimes flowed out of these hardened hoy flows. shells, draining them, and leaving behind many hollow tubes or caves. This basaltic pahoehoe lava looks blocky, due to jointing. Jointing is a system of vertical cracks that Tube openings, such as this one, are caused when form the lava as it cools and contracts, often leav- the tube’s roof of hardened lava collapses. ing the lava separated into blocks and columns. CAUTION - DO NOT ENTER Loose lava rocks can be hazardous 6 HARDY INDIVIDUALS 8 LAVA TUBE LOCATORS As you can see, some Antelope Bitterbrush Purshiia tridenlata These clusters of small trees are “Curleaf Mountain- plants do quite well on mahogany”, a member of the rose family. the flow’s dry, thin soils. Lava joints provide This tree tends to spaces for plants to grow on or near lava “Curleaf Mountain - Mahogany” anchor their roots as do tubes, as does green (Cercocarpus ledifdius) pockets of deeper soil. moss, often indicating the presence of unseen The brush here is dominated by Bitterbrush and hollow tubes below Greenleaf Manzanita. the surface. Bitterbrush has small, soft, pale green leaves and grayish brown bark. When in bloom, its flowers are Could the ground you’re standing on be hollow pale yellow. It is a favorite food for deer. underneath ? 9 GIANT STEPS 13 RED BASALT Notice the three collapses heading Although the red basalt on this spatter cone downhill in a step-like manner. in front of you looks different from the Prior to collapsing, this was one black basalt, their chemical make-up is lava tube. nearly the same. It is the exception that gives red basalt it’s red color. What do you 10 CINDER CONES think that element is ? (Hint: think of rust) During eruption, some lava rocks were exposed to The large “symmetrical” volcano in front of you is more extreme temperatures than others. This addi- Sugarloaf Peak, a young lava cone, probably less tional heat caused much of the iron in the hotter than 10,000 years old. Sugarloaf Peak is topped basaltic lava to oxidize further ( the same process with a cinder cone. To the left, at its base, is an- that happens when iron rusts ); giving it the distinc- other cinder cone. tive red or rusty color. 14 AN OLD FAULT SCARP Look past the rim of this large spatter cone to- Cinder Cones are small volcanic cones built entirely wards the long ridge in the east. This ridge is the of fragmental materials (ash, cinder, etc.) which was Hat Creek Rim, a fault scarp. explosively shot from their vents. There’s another tree-covered cinder cone in front of you to the right, can you find it ? 11 MORE HOLES ! COULD THIS BE PART OF THE SAME COL- Nearly 1 million years ago, active faulting gradu- LAPSED LAVA TUVE YOU SAW AT POST #9 ? ally dropped a block of the Earth’s crust ( now Hat Creek Valley ) nearly 1,000 feet below the top of the Hat Creek Rim, leaving behind this large fault 12 SPATTER CONES scarp. As lava poured from 15 COLLAPSE PIT these fissure vents, built-up gaseous pres- This vent was exposed when part of this small sure near the vents spatter cone’s flank collapsed ( notice the collapse caused some of the lava rubble on the bottom ). to be hurled up in The lava that once poured from this vent built the fountains. overlying spatter cone and the lava tube systems in As large air-born clots of lava fell back to the lava the immediate area. As the eruption activity dimin- surface, they “flattened” and plastered themselves ished, the lava drained, leaving behind this steep together, forming spatter cones around the lava pit. Notice how the small spatter cone almost sealed fountains. itself up. CAUTION - Stay a safe distance back. When lava fountains “died”, they left craters like These are hazardous formations. this one. DO NOT ATTEMPT TO ENTER THINGS TO LOOK FOR ON RETURN TRIP VOLCANOES EVERYWHERE ! 1. Spatter cone ( with a crater 33 ft. in 16 diameter ) 2. Collapsed Lava Tubes Every mountain before you is a volcano, and each in 3. Pahoehoe Lava ( refer to stop # 5 ) its time helped mold the landscape with eruptions 4. Red basalt of ash and lava. 5. Hardy individuals - Bitter brush, and Greenleaf Manzanita To the south is the largest volcano, Lassen Peak (10,457’). Lassen Peak is the southern most active MORE INFORMATION on local geology is volcano in the Cascade Mountain Range, a range available at Subway Cave, an easy 1/3 mile that includes Mt. St. Helens, and which extends into walk that leads you through a large lava tube, Canada. or at the Old Station Visitor Center, and Lassen Volcanic National Park. The rocky mass to Lassen’s right is the Chaos Crags, Subway Cave is located 1/2 mile north of Old and the large pointed volcano to your left is West Station on Highway 89, across from Cave Prospect Peak. Can you see the fire lookout on top ? Campground. 89 Subway Cave Cave Campground a Hat Campground a q 44 Old StationVisitor Information Center 44/89 Spatter Cone Trail & Sanitary Station Old Station Visitor Information Center is lo- Lassen Peak broke out of its long sleep in 1914 cated just south of the Highway 44/89 junction when it started a series of explosive eruptions that in Old Station. Lassen Volcanic National Park lasted intermittently, until 1917. During that time, entrance is 13 miles south of Old Station on significant amounts of erupted ash landed in this Highway 89. area, Much of the soil you see here contains Lassen Peak ash. If you would like learn more about geology, volcanoes, or the Cascade Mountain Range, you might consider reading: 17 THIS IS THE PLACE ! - Fire Mountains of the West by Stephen L. This area is where the Hat Creek Lava Flow origi- Harris nated. The spatter cones and lava mounds on this - Roadside Geology of Northern California by ridge mark the approximate locations of the under- David D. Alt & Donald W. Hyndman lying fissures that fed the lava flow. - Through Vulcan’s Eye by Philip S. Kane As the lava poured out of these fissures, most of it flowed east, down this ridge, and then continued If you have any suggestions or questions about other areas north for 16 miles, following the slope of the land of the Hat Creek Recreation Area, please contact us: through Hat Creek Valley and leaving behind a Lassen National Forest, Hat Creek Ranger thick covering of basalt.
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