Hubbry Logo
Cinder Cone and the Fantastic Lava BedsCinder Cone and the Fantastic Lava BedsMain
Open search
Cinder Cone and the Fantastic Lava Beds
Community hub
Cinder Cone and the Fantastic Lava Beds
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Cinder Cone and the Fantastic Lava Beds
Cinder Cone and the Fantastic Lava Beds
Cinder Cone and the Fantastic Lava Beds
View on Wikipedia
from Wikipedia

Cinder Cone is a cinder cone volcano in Lassen Volcanic National Park within the United States. It is located about 10 mi (16 km) northeast of Lassen Peak and provides an excellent view of Brokeoff Mountain, Lassen Peak, and Chaos Crags.

Key Information

The cone was built to a height of 750 ft (230 m) above the surrounding area and spread ash over 30 sq mi (78 km2). Then, like many cinder cones, it was snuffed out when several basalt lava flows erupted from its base. These flows, called the Fantastic Lava Beds, spread northeast and southwest, and dammed creeks, first creating Snag Lake on the south and then Butte Lake to the north. Butte Lake is fed by water from Snag Lake seeping through the lava beds. Nobles Emigrant Trail goes around Snag Lake and follows the edge of the lava beds.

Its age has been controversial since the 1870s, when many people thought it was only a few decades old. Later, the cone and associated lava flows were thought to have formed about 1700 or during a 300-year- long series of eruptions ending in 1851. Recent studies by U.S. Geological Survey (USGS) scientists, working in cooperation with the National Park Service to better understand volcanic hazards in the Lassen area, have firmly established that Cinder Cone was formed during two eruptions that occurred in the 1650s.

Geography

[edit]

Cinder Cone lies in Lassen and Shasta counties, in Northern California, within the United States. Located 1.5 mi (2.4 km) southwest of Butte Lake and 2.2 mi (3.5 km) southeast of Prospect Peak[1] (which dwarfs Cinder Cone),[2] it is also sometimes referred to as Black Butte or Cinder Butte.[1] The volcano lies in the northeastern corner of Lassen Volcanic National Park.[3]

The summit crater of Cinder Cone

Nearby Snag Lake formed when lava known as the Painted Dunes flows dammed the Grassy Creek stream, which is fed by water from the central plateau of the national park area. Water from this lake feeds Butte Lake, located 2 mi (3.2 km) to the north. Butte Lake is the sole remaining fragment of a much larger body of water filled with lava during Cinder Cone's eruptive period. Diatomite sediment, formed from the aggregation of diatoms on the lake's floor, run along the edges of the Fantastic Lava Beds and mark the margins of this former lake.[4]

Description and geology

[edit]
Cinder Cone is in Lassen Volcanic National Park.

Cinder Cone is a 700 ft (210 m)-high volcanic cone of loose scoria.[5] The youngest mafic volcano in the Lassen volcanic center,[6] it is surrounded by unvegetated block lava and has concentric craters at its summit,[5] which have diameters of 1,050 ft (320 m) and 590 ft (180 m).[3] Cinder Cone comprises five basaltic andesite and andesite lava flows, and it also has two cinder cone volcanoes, with two scoria cones, the first of which was mostly destroyed by lava flows from its base.[6] Cinder cone volcanoes are typically monogenetic, meaning that they only undergo one eruptive period before ceasing activity forever. These eruptions often consist of the ejection of tephra, though they may also generate lava flows, which often originate from vents near the base rather than the summit of the volcanic edifice.[7]

The summit of Cinder Cone has a crater with a double rim (photo), probably created by two different phases of one eruptive period.[8] The cone also has a widespread ash deposit identifiable for 8 to 10 mi (13 to 16 km) from the cone. Blocks of red, cemented scoria within the Painted Dunes lava flows (photo) are pieces of this earlier cone, which were carried away by the flowing lava.[4]

When Cinder Cone formed, the magma feeding the eruption changed composition, shifting from basaltic andesite to andesite before returning to basaltic andesite with increased titanium content. While basaltic andesites are volcanic rocks containing 53 to 57% silica, andesites are those containing 57 to 63% silica. The lava flows and scorias at the volcano closely resemble each other despite distinct chemical compositions, forming dark, fine-grained rocks, with a few visible crystals of the minerals olivine, plagioclase, and quartz.[4]

The early group of volcanic deposits at Cinder Cone, which have relatively little titanium, include older scoria cone, the Old Bench flow, the two Painted Dunes flows, and the lower part of the widespread ash layer. The second group, erupted later and comparatively rich in titanium, consists of the large, younger scoria cone, the upper part of the ash layer, and the two Fantastic Lava Beds flows. Radiocarbon dating places these occurrences between 1630 and 1670 CE.[4] At the Old Bench and Painted Dunes lava flows, the volcanic ash is brightly oxidized because it interacted with the lava flows when they were still hot. It shares its compositional group with the Fantastic Lava Beds flows, which represent the last flows erupted at Cinder Cone. Ultimately, the eruptive sequence at Cinder Cone took place over the course of several months.[4]

An unusual characteristic of the Fantastic Lava Beds is the presence of anomalous quartz crystal xenocrysts (foreign bodies in igneous rock). Geologists think that they were picked up from wall rocks by the lava as it moved toward the surface.[9]

Human history

[edit]

Beginnings of a controversy

[edit]
The fresh look of the Fantastic Lava Beds (seen from Cinder Cone) led earlier observers to conclude they were at most a few decades old

After traveling through Northern California in the spring of 1851, two gold prospectors reported seeing an erupting volcano that "threw up fire to a terrible height"[4] and that they had walked for 10 mi (16 km) over rocks that burned through their boots.[10] This narrative complemented several accounts of activity at the volcano across 1850 and 1851, which all claimed to observe the eruptions from at least 40 mi (64 km) away.[5]

During the early 1870s, medical doctor and amateur scientist H. W. Harkness from San Francisco, California, visited the Cinder Cone area.[11] Intrigued by the "apparent youthfulness" of the area's volcanic landmarks, he observed several features to argue that Cinder Cone was only about 25 years old.[4] He presented his conclusions at a meeting of the California Academy of Sciences, and was contacted by Academy member Henry Chapman, who informed him of the gold prospector story. A number of other people reached out to Harkness about seeing volcanic activity in Lassen in about 1851, such as O. M. Wozencraft, which led Harkness to think that Cinder Cone had erupted recently.[4]

Though there were multiple reports of eruptive activity near Lassen in Northern California newspapers during the 1850s, the details remain inconsistent. The first such report, which was published in the August 21, 1850, edition of the Daily Pacific News (a San Francisco newspaper), cited an unnamed observer who claimed to have seen "burning lava still running down the sides" at Cinder Cone.[5] In 1859, the San Francisco Times published an article with testimony from Wozencraft and a companion in which they claimed to have seen flames in the sky from a volcanic eruption from a location west of the Lassen area. Receiving widespread attention, the article was widely reprinted, despite the fact that the account lacked specific dates or locations for their claims. Poking fun at Wozencraft's claims, the Shasta Republican wrote several times throughout April 1859 that "the Dr.'s imagination is far more active than any volcano in our County or State."[4] Harkness' 1875 report cites the date of Wozencraft's sighting to be the winter of 1850–1851.[4]

Early geologic studies

[edit]
The first geologist to study Cinder Cone was Joseph S. Diller (pictured).

The first geologist to study Cinder Cone was Joseph Diller.[12][13] One of the first USGS scientists to study volcanoes, Diller took careful notes on Cinder Cone and interviewed many Native Americans and European trappers and settlers inhabiting the Lassen region during 1850, none of whom remembered volcanic activity there. Aware of an "emigrant road" (the Nobles Emigrant Trail), which had been utilized by settlers coming to California in the early 1850s, that passes close to the base of Cinder Cone, he interviewed a number of people who "crossed the trail" in 1853.[4] They noted that a large, solitary willow bush (Salix scouleriana) near the summit of Cinder Cone had not been destroyed by any eruptive activity. The bush is still alive and has not been altered much since.[4]

Because the willow at the summit of Cinder Cone was already mature in 1853, Diller concluded it was extremely unlikely that an eruption could have occurred there in the winter of 1850.[4] He also noted that trees rooted in volcanic ash erupted from the cone were about 200 years old and that the oldest trees on related lava flows were about 150 years old. Diller believed he recognized two eruptive sequences, which each produced lava flows. However, he thought that only the older eruption was explosive, creating Cinder Cone and the ash deposits. In regard to the explosive eruption, he concluded that "Whatever may be the historical testimony as to the time of the eruption, the geologic evidence clearly demonstrates that it must have occurred long before the beginning of the present century" (before 1800).[4] Diller therefore speculated that the explosive eruption had occurred between about 1675 and 1700 and that the younger, quiet eruption was "certainly" sometime before 1840.[4]

On May 6, 1907, both Cinder Cone and Lassen Peak were designated national monuments, administered by the National Forest Service.[14] Cinder Cone's name was officially recognized by the United States Board on Geographic Names in 1927.[1] In the mid-1930s, USGS volcanologist R. H. Finch attempted to improve on Diller's work. On the basis of other studies done at Cinder Cone, Finch thought (1) that there had been at least five separate lava-flow events, as suggested by crude, experimental magnetic measurements;[15] (2) that the youngest lava flow was extruded in 1851, accepting Harkness' (1875) historical "evidence" and ignoring Diller's interviews and conclusions; and (3) that there had been at least two distinct explosive eruptions of the cone.[16] Using these assumptions and tree-ring measurements, Finch proposed a complex and detailed eruptive chronology for Cinder Cone that spanned nearly 300 years.[17] From measurements of the rings of one particular tree, which showed two periods of slow growth, he thought that the two explosive eruptions occurred in 1567 and 1666. He also concluded that the five lava flows were extruded in 1567, 1666, 1720, 1785, and 1851.[4]

New geologic studies

[edit]

After Finch published his work in 1937, few additional studies were done on volcanic hazards in the Lassen area. However, that changed after the 1980 eruption of Mount St. Helens in Washington. As a result, the USGS began reevaluating the risks posed by other potentially active volcanoes in the Cascade Range, including those in Lassen Volcanic National Park. Since that time, USGS scientists have been working in cooperation with the National Park Service to better understand volcanic hazards in the Lassen area. As part of this work, the history of Cinder Cone has been reexamined. Most of the features of Cinder Cone have changed little since Harkness first described them in the 1870s, but all of the assumptions on which Finch based his conclusions have now been shown to be incorrect.[4]

Through new field and laboratory work and by reinterpreting data from previous studies, USGS scientists have shown that the entire eruptive sequence at Cinder Cone represents a single continuous event. Because the orientation of the Earth's magnetic field in northern California during the 1850s is well known and is different from the remnant magnetizations at Cinder Cone, the lava flows there could not have been erupted in 1850 or 1852. Also, there are no discernible differences in the magnetic orientation recorded by any of the Cinder Cone lava flows, and so the flows had to be extruded during an interval of less than 50 years.[4]

Although paleomagnetic evidence can be used to rule out the 1850s as the age of Cinder Cone, it does not provide an actual age for its eruption. By measuring levels of carbon-14 in samples of wood from trees killed by the eruption of Cinder Cone, USGS scientists obtained a radiocarbon date for the eruption of between 1630 and 1670. Such a date is also consistent with the remnant magnetization preserved in the lava flows. The series of eruptions that produced the volcanic deposits at Cinder Cone were complex and are by no means completely understood. However, the new studies done by USGS scientists refute the purported accounts of an eruption in the early 1850s and confirm Diller's (1891, 1893) interpretation that Cinder Cone erupted in the latter half of the 17th century. They also suggest that the 1666 tree-ring date proposed by Finch (1937) for his "second" explosive eruption at Cinder Cone might actually date the entire eruptive sequence.[4][18]

See also

[edit]

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Cinder Cone and the Fantastic Lava Beds

View on Grokipedia
from Grokipedia
is a 700-foot-high (213 m) cone volcano located in the northeast corner of , , formed during a single eruptive episode between 1630 and 1670 CE that produced the extensive Fantastic Lava Beds, a series of blocky basaltic-andesite flows covering approximately 8 square miles (21 km²). The eruption, dated precisely to around 1666 CE through dendrochronological evidence from trees buried by its ash and lava, represents the most recent volcanic activity in the Lassen Volcanic Center and exemplifies in the . The cone itself consists of loose, dark and cinder deposits, rising steeply to a double-rimmed summit crater that offers panoramic views of surrounding features like and Snag Lake. The Fantastic Lava Beds, erupted late in the sequence from vents at the cone's base, form rugged block flows with angular, house-sized blocks up to 65–100 feet (20–30 m) high, characterized by a glassy interior and brecciated margins due to the viscous nature of the basaltic-to-basaltic-andesite . These flows, part of two main pulses that likely lasted only a few months, traveled up to 8 miles (13 km) from the vent, burying forests and creating a barren, otherworldly that contrasts with the colorful Painted Dunes formed from oxidized cinders nearby. Proclaimed a U.S. in 1907 by President alongside , the site was incorporated into in 1916, highlighting its value for studying monogenetic volcanism and providing recreational opportunities via a strenuous 4-mile (6.4 km) round-trip trail that ascends the cone's loose slopes. The area's well-preserved features, including ash layers extending 8–10 miles (13–16 km) and evidence of contamination by crustal assimilation, offer insights into the dynamics of small-volume eruptions in subduction zone settings.

Geography

Location and Setting

Cinder Cone is situated in the northeastern portion of in , , at coordinates 40°32′51″N 121°19′12″W. This location places it within Lassen County, with the broader park spanning Lassen and Shasta counties among others. The summit reaches an elevation of 6,907 feet (2,105 meters) above . The site lies approximately 1.5 miles (2.4 kilometers) southwest of Butte Lake and 2.2 miles (3.5 kilometers) southeast of Prospect Peak, while standing about 10 miles (16 kilometers) northeast of . Accessibility to Cinder Cone requires travel via a 6-mile unpaved road off California State Highway 44, leading to the Butte Lake trailhead in the park's remote northeast corner; this route is suitable for most vehicles but demands caution due to its rough surface. As part of , established in 1916 to preserve its volcanic landscapes, exemplifies the southern terminus of the volcanic system, a chain of active volcanoes extending from to . The park's setting amid coniferous forests, alpine meadows, and glacial features provides a diverse backdrop for exploring this and its surroundings.

Topography and Associated Features

Cinder Cone rises 700 feet (213 meters) above the surrounding terrain in the northeastern section of , forming a prominent, symmetrical volcanic edifice composed primarily of loose . Its steep slopes, averaging 30 to 35 degrees, represent the natural for unconsolidated cinder material, making the cone a classic example of a monogenetic volcano's . At the summit, a double-rimmed , approximately 200 feet (61 meters) deep, features concentric rims that reflect multiple phases of eruptive activity. The surrounding landscape includes ash deposits extending up to 8–10 miles (13–16 km) from the cone, blanketing a broad area with that creates a barren, undulating expanse. Nearby features enhance the topographic diversity: Butte Lake lies to the southwest, its shores bordered by recent lava flows, while Snag Lake formed to the north when those flows dammed local drainage. The Painted Dunes, vivid red, orange, and yellow hills of oxidized ash deposits, stretch eastward, their colors resulting from hot ash settling on underlying lava. Prospect Peak, a rising to 8,338 feet (2,541 meters), dominates the western skyline, providing a stark contrast to the cone's sharper profile. Access to Cinder Cone begins at the Butte Lake trailhead, following a 4-mile (6.4-kilometer) round-trip path through forests and over lava fields, with a total elevation gain of 846 feet (258 meters). The hike is challenging due to the loose, sand-like cinders that shift underfoot, particularly on the final 0.5-mile (0.8-kilometer) ascent to the rim, which climbs 200 feet (61 meters) at a steep . From the summit, panoramic views encompass the adjacent Fantastic Lava Beds, a vast field of blocky flows.

Geology

Cinder Cone Formation

Cinder Cone is a classic example of a volcano, a monogenetic constructed primarily from loose , which consists of basaltic to andesitic cinders, bombs, lapilli, and ejected during explosive eruptions. As the youngest volcano in the Lassen volcanic center, it exemplifies the rapid buildup of such features through the accumulation of pyroclastic material around a central vent. The cone rises approximately 215 meters (700 feet) above the surrounding terrain, with its steep sides—sloping at angles up to 30–35 degrees—formed by the ballistic fallout and rolling of fragments that pile up in layers, creating a symmetrical, unbuttressed profile typical of cones. The formation process involved strombolian-style explosive eruptions, where gas-rich basaltic fragmented into pyroclasts upon reaching the surface, propelling them into the air to heights of several hundred meters before they settled back around the vent. This accumulation dominated the cone-building phase during its brief 17th-century activity, with coarser near the summit transitioning to finer layers downslope, resulting in a total volume of estimated at about 0.07 cubic kilometers for the cone itself. A distinctive aspect of the is the presence of unusual xenocrysts, ranging from 1 mm to 10 cm in size, which were incorporated into the mafic through crustal assimilation as the interacted with granitic in the mid- to upper crust. These xenocrysts, often showing rhombohedral cleavage, highlight the magma's rapid contamination and provide evidence of hybrid magmatism in an otherwise system. At the summit, the cone features multiple concentric craters, including a prominent double rim formed by fluctuating eruption dynamics, with the main measuring approximately 800 feet (240 meters) in width and up to 75 meters deep. The inner crater walls expose layered deposits of oxidized , while agglutinated bombs—welded fragments up to 3 meters across—line the base, illustrating the intermittent shifts between explosive and more effusive phases that shaped the final structure. This well-preserved morphology underscores Cinder Cone's status as one of the most intact examples of a young in the .

Eruption Sequence and Products

The eruption of represents a single volcanic event that occurred between 1630 and 1670 CE, with radiocarbon and tree-ring dating indicating a likely culmination around 1666 CE. This monogenetic eruption was characterized by moderate explosivity, primarily Strombolian in style, and produced a range of pyroclastic materials without significant plinian phases. The sequence began with initial explosive activity ejecting basaltic andesite cinders and ash, forming the bulk of the cone through repeated fallout and ballistic emplacement. As the eruption progressed, the composition shifted toward more evolved due to fractional and crustal assimilation, leading to slightly more viscous in later stages. Minor pyroclastic flows occurred intermittently when vents were partially blocked, contributing to localized deposits near the cone. The entire sequence unfolded over a few months, transitioning from dominant production to brief effusive phases, though the explosive products dominated the early buildup. Key products included a widespread ash blanket extending over approximately 30 square miles (78 km²) northeast of the vent, primarily from wind-dispersed fine , and thick scoria deposits that accumulated to form the 700-foot (213 m) high . An estimated 0.03 cubic miles (0.12 km³) of material was ejected in total, with comprising about 20% of the volume, reflecting moderate intensity comparable to VEI 3 eruptions. These deposits buried pre-eruption forests under layers up to several feet thick, preserving paleosols and creating stark, unvegetated landscapes, while also forming new landforms such as the itself and associated sand dunes from wind-reworked .

Fantastic Lava Beds

The Fantastic Lava Beds consist of two extensive blocky 'a'ā lava flows, designated Flow 1 and Flow 2, that erupted from fissures at the base of during its late eruptive phase. These flows, composed primarily of sparsely augite-olivine with SiO₂ contents ranging from 55.1% to 57.3%, exhibit rough, block-covered surfaces formed by the fragmentation of the viscous outer crust as the underlying lava continued to move. Flow 1 reaches thicknesses up to 20 meters (approximately 65 feet) in places, while Flow 2 varies from thin to thicker accumulations, contributing to the overall rugged and chaotic topography. The lava field covers an area of approximately 8 square miles (21 km²), extending northward from the cone toward Butte Lake, where a small on the lake's east shore indicates that the flows underlie much of the basin; the eruptions also blocked local drainage to form nearby Snag Lake. This jumbled expanse of broken blocks and levees creates a "fantastic" appearance of disordered, barren , nearly free of cover, development, or vegetation, with only sparse, immature trees dotting the surface. The flows originated from effusive eruptions around 1666 CE, as determined by tree-ring dating of wood preserved beneath the deposits, marking the terminal phase of Cinder Cone's activity between 1630 and 1670 CE. Geologically, the Fantastic Lava Beds represent the more portion of the eruption's compositional spectrum, with their contrasting the more silicic andesitic materials that built the cone itself, highlighting evolution through processes like fractional crystallization and recharge during the monogenetic event. The flows overlie and interact with earlier deposits from the same eruptive sequence, baking and oxidizing the underlying layers to produce the vibrant , , and black hues of the adjacent Painted Dunes. This association underscores the transition from explosive to effusive activity in the system, providing a key example of how basaltic eruptions can reshape local landscapes in the .

Human History and Scientific Study

Early Observations and Controversy

The first human encounters with Cinder Cone and the surrounding Fantastic Lava Beds occurred amid the , when remote landscapes drew prospectors seeking fortune. In spring , two such prospectors, after traversing the area en route to mining sites, reported observing an that "threw up fire to a terrible height," accompanied by thick smoke and intense heat from freshly ejected material. They claimed to have walked ten miles over scorching rocks that ruined their boots, an account they shared upon reaching Georgetown in El Dorado County, sparking early speculation about recent volcanism in the northeast corner of what would become . These prospector testimonies gained prominence in the 1870s through the efforts of H.W. Harkness, a San Francisco-based physician and amateur , who conducted on-site examinations and interviews. In his 1874 publication, Harkness described the Cinder Cone's pristine, unvegetated form and the fresh appearance of the lava beds, interpreting them as evidence of eruptions just 20–25 years prior. He corroborated the 1851 accounts with statements from other contemporaries, including Dr. O.M. Wozencraft, who in 1850–1851 observed a steady "great fire" glowing eastward from near Red Bluff for multiple nights, and Dr. J.B. Trask, who noted luminous displays visible from Rich Bar about 40 miles away. Harkness's work, disseminated through scientific proceedings, portrayed the site as a site of ongoing volcanic threat. The reports ignited national curiosity about "new" volcanic activity in the , a region already associated with dramatic eruptions like those at , and were amplified by local folklore of fiery mountains and seismic unrest among settlers and Native communities. Without precise dating methods, such narratives easily aligned with the landscape's youthful look, drawing media and scientific attention to potential American analogs of European volcanoes like Vesuvius. Yet, skepticism emerged almost immediately, as no broader historical records documented widespread ash deposits, seismic tremors, or damage to settlements that an 1850s event of the described scale would likely produce; newspapers and settler journals from the era, including those in nearby Shasta and Plumas counties, lacked corroborating mentions of fallout or disruptions. Early geologist Joseph S. Diller underscored these inconsistencies in 1891, noting the testimonies' isolation amid otherwise silent archives.

Initial Geologic Investigations

The initial geologic investigations of Cinder Cone and the Fantastic Lava Beds were conducted by U.S. Geological Survey (USGS) geologist Joseph Diller during the 1890s, marking the first systematic scientific examination of the site. Diller's surveys, published in 1891 and 1893, involved detailed field mapping of the cone's morphology, sample collection of volcanic materials, and observations of vegetation growth to estimate eruption ages. He noted mature Scouler willows on the crater rim that would have required decades to establish by the 1850s, as well as approximately 200-year-old ponderosa pines rooted in and growing through the layers, indicating the primary explosive eruptions predated 1800 CE. These findings refuted earlier anecdotal claims from the 1850s of recent activity, correlating instead with limited historical records from Native American accounts and early settlers. Building on Diller's work, R.H. conducted further studies in , focusing on dendrochronological and geophysical analyses to refine the eruption timeline. 's 1937 publication employed tree-ring dating from pine samples collected across ash deposits and lava flows, combined with experimental magnetic measurements of the basalts conducted by A.E. Jones in 1928, to differentiate flow sequences. These methods, alongside field mapping and cross-references to regional historical records, led to propose a series of multiple eruptions spanning from 1567 CE to 1851 CE, including explosive events in 1567 and 1666 CE followed by effusive flows. His analysis identified five distinct lava flows within the Fantastic Lava Beds, attributing them to this extended period of activity. Collectively, Diller's and Finch's investigations established as one of the youngest volcanic features in the Lassen region, contrasting with older Pleistocene formations elsewhere in , while highlighting the site's activity through integrated botanical and stratigraphic evidence. However, their reliance on indirect dating techniques perpetuated uncertainties in the precise eruption chronology, setting the stage for later refinements.

Modern Analyses and Resolutions

In the 1980s and 1990s, U.S. Geological Survey (USGS) researchers conducted on organic materials buried by the Cinder Cone eruptions, including charred wood from trees toppled by lava flows and bark fragments preserved under ash deposits. These analyses targeted samples from the Fantastic Lava Beds and surrounding areas, such as a quaking aspen buried by the initial lava flow and drowned trees in Snag Lake formed by later flows blocking Grassy Creek. Multiple samples yielded uncalibrated ages clustering around 264 ± 28 years (BP), with specific results including 255 ± 46 BP for aspen wood and 265 ± 63 BP for charred Jeffrey pine bark. Calibrated to calendar years using standard dendrochronological curves, these dates confirm a single eruptive episode between 1630 and 1670 CE, resolving long-standing debates over multiple or recent activity. This radiocarbon evidence directly refuted claims of 1850s eruptions, attributing observations of "fresh" features—like a mature bush noted in 1853 and young tree growth on flows—to misinterpretations of the 17th-century deposits rather than new . Complementary paleomagnetic studies on the lava flows measured the recorded direction and intensity of , revealing uniform signatures across all units that align with 17th-century geomagnetic data and indicate the entire sequence formed within a brief span of less than 50 years. Integration with ash stratigraphy further supported this timeline, as the widespread layer (extending 8–10 miles) shows consistent oxidation patterns on older flows like the Old Bench and Painted Dunes, consistent with a short-lived event rather than prolonged activity. These combined methods pinpointed the main eruption to approximately 1666 CE, corroborating earlier tree-ring evidence while establishing no historic activity after 1700 CE. The findings, summarized in a 2000 USGS Fact Sheet, conclusively resolved the age "mystery" that had persisted since the and enhanced volcanic hazard assessments for by clarifying the monogenetic nature of the system and its low recurrence risk in the .

References

  1. https://pubs.usgs.gov/fs/2000/fs023-00/fs023-00.pdf
  2. https://www.nps.gov/articles/000/block-flows.htm
  3. https://www.nps.gov/lavo/learn/news/nr07_cinder_lassen_nm_100years.htm
  4. https://www.usgs.gov/publications/understanding-melt-evolution-and-eruption-dynamics-1666-ce-eruption-cinder-cone-lassen
  5. https://www.nps.gov/places/cinder_cone.htm
  6. https://www.nps.gov/articles/000/volcanic-resources-summary-lassen-volcanic-national-park.htm
  7. https://edits.nationalmap.gov/apps/gaz-domestic/public/gaz-record/258368
  8. https://www.nps.gov/lavo/learn/kidsyouth/upload/Lassen-Volcanic-National-Park-Introduction.pdf
  9. https://pubs.usgs.gov/sim/2899/
  10. https://npshistory.com/publications/lavo/index.htm
  11. https://www.nps.gov/articles/nps-geodiversity-atlas-lassen-volcanic-national-park-california.htm
  12. https://npshistory.com/publications/lavo/brochures/cinder-cone-nature-trail-1999.pdf
  13. https://www.nps.gov/lavo/learn/kidsyouth/upload/Lassen-Geology.pdf
  14. https://www.summitpost.org/prospect-peak/860076
  15. https://www.nps.gov/lavo/planyourvisit/hiking_cinder_cone2.htm
  16. https://pubs.usgs.gov/sim/2899/data/sim2899_pamphlet.pdf
  17. https://www.usgs.gov/volcanoes/lassen-volcanic-center/science/geology-and-history
  18. https://www.usgs.gov/volcanoes/lassen-volcanic-center/science/cinder-cone
  19. https://www.researchgate.net/publication/258466811_Stratigraphy_and_compositional_evolution_of_Cinder_Cone_a_composite_monogenetic_cone_in_Lassen_Volcanic_National_Park_California
  20. https://pubs.geoscienceworld.org/gsa/books/edited-volume/2728/chapter/150797300/Diffusion-timescales-at-the-Chaos-Crags-Lassen
  21. https://geo.libretexts.org/Sandboxes/ajones124_at_sierracollege.edu/Geology_of_California_%28DRAFT%29/07%253A_Cascade_Range_and_Modoc_Plateau/7.06%253A_Lassen_Volcanic_National_Park
  22. https://npshistory.com/publications/lavo/pc-v5-1874.pdf
  23. https://pubs.usgs.gov/bul/0079/report.pdf
  24. https://pubs.usgs.gov/fs/2000/fs023-00/
  25. https://pubs.usgs.gov/of/2002/of02-290/
Add your contribution
Related Hubs
User Avatar
No comments yet.