Radiocarbon Ages and Environments of Deposition of the Wono and Trego Hot Springs Tephra Layers in the Pyramid Lake Subbasin, Nevada

Benson, Larry; Smoot, Joseph P.; Kashgarian, Michaele; Sarna-Wojcicki, Andrei M.; Burdett, James W.

doi:10.1006/qres.1997.1897

Cited by 44 publications

(66 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A radiocarbon date on organic carbon beneath the Trego Hot Springs bed at Pyramid Lake in western Nevada is 23,200 ± 300 yr B.P., or a reservoircorrected calibrated age of ca. 27 ka (Benson et al, 1997;MIS 3.1).…”

Section: Evolved Pleistocene Rhyodacites Encounter Icementioning

confidence: 99%

Eruptive history and geochronology of Mount Mazama and the Crater Lake region, Oregon

Bacon¹,

Lanphere²

2006

Geological Society of America Bulletin

166

133

View full text Add to dashboard Cite

Geologic mapping, K-Ar, and 40 Ar/ 39 Ar age determinations, supplemented by paleomagnetic measurements and geochemical data, are used to quantify the Quaternary volcanic history of the Crater Lake region in order to defi ne processes and conditions that led to voluminous explosive eruptions. The Cascade arc volcano known as Mount Mazama collapsed during its climactic eruption of ~50 km 3 of mainly rhyodacitic magma ~7700 yr ago to form Crater Lake caldera. The Mazama edifi ce was constructed on a Pleistocene silicic lava fi eld, amidst monogenetic and shield volcanoes ranging from basalt to andesite similar to parental magmas for Mount Mazama. Between 420 ka and 35 ka, Mazama produced medium-K andesite and dacite in 2:1 proportion. The edifi ce was built in many episodes; some of the more voluminous occurred approximately coeval with volcanic pulses in the surrounding region, and some were possibly related to deglaciation following marine oxygen isotope stages (MIS) 12, 10, 8, 6, 5.2, and 2. Magmas as evolved as dacite erupted many times, commonly associated with or following voluminous andesite effusion. Establishment of the climactic magma chamber was under way when the fi rst preclimactic rhyodacites vented ca. 27 ka. The silicic melt volume then grew incrementally at an average rate of 2.5 km 3 k.y. -1 for nearly 20 k.y. The climactic eruption exhausted the rhyodacitic magma and brought up crystal-rich andesitic magma, mafi c cumulate mush, and wall-rock granodiorite. Postcaldera volcanism produced 4 km 3 of andesite during the fi rst 200-500 yr after collapse, followed at ca. 4800 yr B.P. by 0.07 km 3 of rhyodacite. The average eruption rate for all Mazama products was ~0.4 km 3 k.y. -1 , but major edifi ce construction episodes had rates of ~0.8 km 3 k.y. -1 . The longterm eruption rate for regional monogenetic and shield volcanoes was ~0.07 km 3 k.y. -1 , but only ~0.02 km 3 k.y. -1 when the two major shields are excluded. Plutonic xenoliths and evidence for crystallization differentiation imply that the amount of magma intruded beneath Mount Mazama is several times that which has been erupted. The eruptive and intrusive history refl ects competition between (1) crystallization driven by degassing and hydrothermal cooling and (2) thermal input from a regional magma fl ux focused at Mazama. Before ca. 30 ka, relatively small volumes of nonerupted derivative magma crystallized to form a composite pluton because the upper crust had not been heated suffi ciently to sustain voluminous convecting crystal-poor melt. Subsequently, and perhaps not coincidentally, during MIS 2, a large volume of eruptible silicic magma accumulated in the climactic chamber, probably because of heating associated with mantle input to the roots of the system as suggested by eruption of unusually primitive magnesian basaltic andesite and tholeiite west of Mazama. Sediment gravity-flow deposits (Hol.) Talus (Hol. and Pleist.) Landslide deposits (Hol.) Glacial deposits, undivided (Pleist.) Andesite of the E basin (Hol.) Lava Andesite of ...

show abstract

Section: Evolved Pleistocene Rhyodacites Encounter Icementioning

confidence: 99%

Eruptive history and geochronology of Mount Mazama and the Crater Lake region, Oregon

Bacon¹,

Lanphere²

2006

Geological Society of America Bulletin

166

133

View full text Add to dashboard Cite

show abstract

“…Sediments above the Wono tephra in PLC92B and at the Pyramid Island site show evidence of shallow-water conditions and subaerial exposure (Figs. 7 and 8 in Benson et al, 1997). This suggests that the rate of sedimentation between the deposition of the THS and Wono tephra was not constant and should not be used to assign ages to higher or lower intervals at these sites.…”

Section: The Age Of Ash X15 In the Pyramid Lake Basinmentioning

confidence: 99%

“…Thus it was deposited in 61 m of water at the Wizards Cove site and in 43 m of water at the Pyramid Island and Pelican Point sites. Sediments between the Timber Lake and Wono tephra generally indicate fairly deep water conditions (Benson et al, 1997). We, therefore, elected to use age controls located below the Wono tephra to calculate ages of the Timber Lake and Ash x15 events.…”

Section: The Age Of Ash X15 In the Pyramid Lake Basinmentioning

confidence: 99%

Age of the Mono Lake excursion and associated tephra

Benson

Liddicoat

Smoot

et al. 2003

Quaternary Science Reviews

Self Cite

View full text Add to dashboard Cite

The Mono Lake excursion (MLE) is an important time marker that has been found in lake and marine sediments across much of the Northern Hemisphere. Dating of this event at its type locality, the Mono Basin of California, has yielded controversial results with the most recent effort concluding that the MLE may actually be the Laschamp excursion (Earth Planet. Sci. Lett. 197 (2002) 151). We show that a volcanic tephra (Ash x15) that occurs near the midpoint of the MLE has a date (not corrected for reservoir effect) of 28,6207300 14 C yr BP (B32,400 GISP2 yr BP) in the Pyramid Lake Basin of Nevada. Given the location of Ash x15 and the duration of the MLE in the Mono Basin, the event occurred between 31,500 and 33,300 GISP2 yr BP, an age range consistent with the position and age of the uppermost of two paleointensity minima in the NAPIS-75 stack that has been associated with the MLE (

show abstract

“…Hence, an estimate of the radiocarbon age was generally obtained from the aquatic organic matter (bulk lake sediments) or authigenic inorganic carbonate (e.g., Zhang et al, 1998;Eisma et al, 2000). Although the 14 C method has been used successfully to date bulk lake sediments (e.g., Benson et al, 1997;Lowe et …”

mentioning

confidence: 99%

Variations in radiocarbon ages of various organic fractions in core sediments from Erhai Lake, SW China.

Zheng

2003

Geochem. J.

View full text Add to dashboard Cite

Radiocarbon Ages and Environments of Deposition of the Wono and Trego Hot Springs Tephra Layers in the Pyramid Lake Subbasin, Nevada

Cited by 44 publications

References 16 publications

Eruptive history and geochronology of Mount Mazama and the Crater Lake region, Oregon

Eruptive history and geochronology of Mount Mazama and the Crater Lake region, Oregon

Age of the Mono Lake excursion and associated tephra

Variations in radiocarbon ages of various organic fractions in core sediments from Erhai Lake, SW China.

Contact Info

Product

Resources

About