Lunar Crater volcanic field
Lunar Crater volcanic field | |
---|---|
Highest point | |
Elevation | 2,255 m (7,398 ft)[1] |
Coordinates | 38°N 116°W / 38°N 116°W[2] |
Geography | |
Geology | |
Last eruption | 38,100 ± 10,000 years ago |
Lunar Crater volcanic field is a
The volcanic field has formed on top of older, Oligocene to Miocene age volcanic rocks and calderas, but its own activity commenced only about 6 million years ago. The reasons for the volcanic activity there are not well known. The volcanic field has produced various types of basaltic magma and also trachyte; the most recent eruption was about 38,000 years ago and renewed activity is possible.
Etymology and human use
The volcanic field is named after the Lunar Crater vent,[3] the most distinctive vent in the volcanic field.[1] The area is dry and rugged and thus uninhabited.[4] Owing to its diverse geology and accessibility, Lunar Crater volcanic field was used to test prototype Mars rovers[5] and as a training ground for astronauts[6] for the Moon landings.[4] Parts of the volcanic field lie within the Palisade Mesa wilderness study area,[7] and Lunar Crater is classified as a National Natural Landmark, known as Lunar Crater National Natural Landmark.[8]
Geography and geomorphology
The Lunar Crater volcanic field is located in
The volcanic field covers a 50 miles (80 km) long and 12.4–6.2 miles (20–10 km) wide area
Erosion has led to
The 5.4 square miles (14 km2)
Individual vents
Lunar Crater itself is almost circular and embedded in basaltic lavas, underlying tuffs and two older volcanic cones including Lunar Cone. A tephra ring (ring of volcanic material) defines a 3,600 feet (1,100 m) wide and 430 feet (130 m) deep crater[14] which is the endpoint of a small canyon that appears to predate the formation of Lunar Crater. An alluvial fan and a playa fill the bottom of the crater,[2] which is the lowest point in this volcanic field,[4] while its margins are surrounded by tephra beds including ash, lapilli, scoria and tuff blocks; it appears that most of these are older rocks that were torn out of the ground and ejected during the formation of Lunar Crater.[39] Cinder cones are found at Lunar Crater;[29] two vents east and southeast from Lunar Crater are known as North Kidney Butte and South Kidney Butte.[40]
The extremely well preserved[17] Marcath cone (also known as Black Rock[41][1]) only a few kilometers north of U.S. Route 6[42] is an approximately 490 feet (150 m) high and 1,600 by 3,000 feet (500 m × 900 m) wide volcanic cone, which formed over a fissure vent. Lava flows emanate from its western side, which reach lengths of several kilometers and after bypassing an older cone emerge onto the valley floor.[43] The flows have flow fronts about 16 feet (5 m) high;[44] lobes, inflation structures and material rafted off the cone appear on the lava flows,[45] which are classified as aa lava.[46] During the eruption of Marcath, tephra was emplaced northeastward for over 3.1 miles (5 km) and is formed by lapilli and scoria;[44] another tephra deposit extends south from Marcath cone.[47] The Marcath cone forms the Marcath unit,[43] the total volume of rocks is about 0.024 cubic miles (0.1 km3).[48]
The eroded[49] Kimana ("butterfly" in Shoshone) volcano is formed by aa lava flows and pyroclastic deposits that cover an area of 10 square miles (26 km2) and have a volume of 0.096 cubic miles (0.4 km3).[50] Broken Cone volcano along with several neighbouring bodies likely formed atop a fault (an offset in the ground formed by tectonic movements[51]) and consists of a pyroclastic pile, while the neighbouring bodies are remnants of lava flows.[52] There are also dykes, and the volcano may have featured a now-disappeared scoria cone.[53]
Easy Chair is an about 790 feet (240 m) high and c. 1.6 miles (2.5 km) long ridge in the Lunar Lake basin. The ridge is formed by pyroclastics emplaced on a fissure vent and partly buried/destroyed by two scoria cones and a maar; the cones in turn are the source of a lava flow field. The total volume of this structure is about 0.024 cubic miles (0.1 km3), without counting a poorly measured tephra deposit.[10]
Bea's Crater just southeast from Marcath volcano[38] is the third maar in the volcanic field[54] and appears to have had a complex history.[55] It formed within a dense cluster of older vents as two overlapping roughly 1,440 feet (440 m) and 3,440 feet (1,050 m) wide craters with a maximum depth of 482 feet (147 m); at the bottom lies a playa[38] and to its north lies Northeast Cone, which formed together with Bea's Crater.[56] Deposits including lapilli tuffs and possibly older volcanics surround Bea's Crater.[57] The so-called "Middle Maar" is the fourth maar in the volcanic field.[55]
Dark Peak in the Reveille Range is a Pliocene volcano whose underground structure, a dyke (a steep, tabular magma intrusion into rock[58]), is exposed as an almost 0.62 miles (1 km) long body that also contains the main conduit of the volcano.[59] There are also other traces of dykes[60] that formed when magma propagated away from the vent,[61] and a subdued lava field west from the vents.[62] Erosion has removed most of the volcano, exposing part of the underlying terrain.[63]
Geology
Regional
The Basin and Range province has had a complicated geological history
The Lunar Crater volcanic field is part of a larger
Local
Older volcanic activity occurred in the field during the
These older volcanics also form the basement (underground rock surface[79]) in the area, while parts of the region are covered by alluvium (sediment that was transported by water[80]);[81] sometimes the older volcanics are buried beneath this alluvium and playa deposits.[10] In turn, Paleozoic rocks crop out at the northeastern margin of the Lunar Crater volcanic field[26] and underlie the older volcanics.[64][54] Finally, Proterozoic crystalline rocks occur within the crust.[17] The geology of the region is dominated by fault-separated blocks with only little folding.[78]
Some vents form alignments, and the positions of (not all) individual volcanoes appear to be controlled by normal faults,[3] although isolated volcanoes or clusters also occur[19] and the ascent of magma at many vents was influenced by the general tectonic regime rather than by specific faults.[82] The faults have also influenced the older volcanism[69] and that in turn the Lunar Crater volcanic field.[83] Volcanic activity has buried many of the faults in the area[69] and there is little evidence of ongoing faulting and deformation.[84]
Composition
The Lunar Crater vents have erupted alkali basalts; trachyte occurs at two lava domes[3] and basalts, basanite, tephrite and trachybasalt have been reported as well.[85] In general, the volcanic rocks define an ocean island basalt suite that originated in the asthenosphere.[26] The rocks contain phenocrysts.[d] inclusions and nodules.[e] Alteration has formed chlorite, epidote and sericite.[88] In the northern part of the volcanic field, lavas have a porphyritic (with a texture characterized by visible crystals[89]) appearance.[17]
The magma appears to originate from a heterogeneous mantle and ponds and crystallizes underneath and inside the crust[90] but without stalling in long-lived magma chambers,[91] before rapidly rising to the surface.[92] Each volcano was supplied by one batch of magma.[26]
Climate and vegetation
The climate is
Eruption history
The volcanic field was active in the Miocene[19]/Pliocene and Pleistocene,[3] with the oldest eruptions dated to about 6 million years ago.[19] Volcanism occurred in four stages,[94] with activity peaking every 1-2 million years.[95] The southern volcanics on Reveille Range[19] and in Kawich Valley[72] are the older ones, while more recent eruptions occurred farther north on Pancake Range although at any given point of time the field was active over a large area. As a consequence of the long duration of volcanism, the various volcanic centers have been eroded at varying degrees[19] while volcanism moved to the north[96] at a rate of about 0.39 inches per year (1 cm/year).[97] A mean magma flux rate of 4.1×10−6 cubic miles per year (0.000017 km3/a) has been reported for Lunar Crater volcanic field,[98] with a tendency to decrease over time[95] and changes in the composition.[17]
Many eruptions in Lunar Crater volcanic field have been dated; aside from radiometric dating[99] differences in the grade of weathering and erosion have also been used to determine the relative age of volcanic units[78] as older vents are often degraded and buried by soils:[100]
- Kimana is probably about 5.7 ± 0.2 million years old.[50]
- Qc cone was emplaced 1.61 ± 0.14 million years ago.[3]
- The Mizpah unit was emplaced between 740,000 and 620,000 years ago.[66]
- Easy Chair is dated to be 140,000 ± 5,000 years old.[10]
- The Giggle Springs unit was dated to less than 81,000 ± 5,000 years ago.[66]
Lunar Crater's own age is not known,[3] a tephra potentially correlated to it may have been emplaced 600,000 ± 30,000 to 224,000 ± 43,000 years ago. Scarce traces of erosion imply a late Pleistocene age, however,[14] with a more recent age estimate of 190,000 - 72,000 years ago.[20] Bea's Crater is also not directly dated but may be 300,000 - 100,000 years old.[38]
The emplacement of individual vents often began with explosive eruptions that formed mounds, before effusive eruptions (eruptions characterized by the production of lava flows[101]) generated lava flows.[102] The volcanic eruptions had characteristics of Hawaiian or Strombolian eruptions, with maars and tuff rings forming where ascending magma interacted with groundwater[19] and volcanic cones where ejecta from the vent piled up and formed a cone.[103] In some places, several eruptions occurred over timespans of over one million years and gave rise to closely spaced vents.[3] Lava flows were produced at rates of about 35–3,531 cubic feet per second (1–100 m3/s)[22] and at Kimana and Broken Cone probably occurred through lateral vents.[104] The Marcath eruption may have lasted up to 20 days;[105] it probably occurred during southwesterly wind and formed a 3.7–5.0 miles (6–8 km) high eruption column.[106]
Most recent eruption and hazards
The most recent eruption occurred 38,000 ± 10,000 years ago
Notes
- ^ The exact number of vents is not known[19] as many of them are eroded or otherwise degraded[20] and some volcanoes may be buried under sediments in the basins.[18] Older tephra deposits crop out in a quarry.[21]
- ^ Dry lake[36]
- clinopyroxenite, dunite,[87] gabbro,[10] harzburgite, lherzolite,[87] peridotite,[88] spinel and wehrlite[87]
- ^ Formerly it was dated to be 350,000 ± 50,000 years old.[107]
References
- ^ a b c d "Lunar Crater". Global Volcanism Program. Smithsonian Institution.
- ^ a b c d Valentine, Shufelt & Hintz 2011, p. 757.
- ^ a b c d e f g h i j k l m n o Valentine, Shufelt & Hintz 2011, p. 755.
- ^ a b c d e Orndorff, Wieder & Filkorn 2001, p. 178.
- ISSN 2156-2202.
- ISSN 0032-0633.
- ^ Diggles et al. 1986, p. B2.
- ^ a b Diggles et al. 1986, p. B1.
- ^ "Cenozoic rocks of Nevada: Four maps and brief description of distribution, lithology, age, and centers of volcanism". NBMG Publications. p. 3. Retrieved 2019-07-29.
- ^ a b c d e f g h Valentine & Cortés 2013, p. 2.
- ^ Yogodzinski et al. 1996, p. 17426.
- ^ a b c Turrin, Abrahams & Dohrenwend 1987, p. 407.
- ^ a b Tadini et al. 2014, p. 2.
- ^ a b c d e f Valentine, Shufelt & Hintz 2011, p. 756.
- ^ Scott & Trask 1971, p. 11.
- ^ Orndorff, Wieder & Filkorn 2001, p. 181.
- ^ a b c d e f g h Rasoazanamparany et al. 2015, p. 77.
- ^ a b Turrin et al. 2017, p. 395.
- ^ a b c d e f g h i j Hintz & Valentine 2012, p. 21.
- ^ a b Turrin et al. 2017, p. 394.
- ^ Turrin et al. 2017, p. 424.
- ^ a b Valentine, Shufelt & Hintz 2011, p. 762.
- ^ Gates & Ritchie 2006, p. 1.
- ^ Turrin et al. 2017, p. 433.
- ^ Hintz & Valentine 2012, p. 23.
- ^ a b c d Tadini et al. 2014, p. 3.
- ^ Gates & Ritchie 2006, p. 157.
- ^ Turrin et al. 2017, p. 414.
- ^ a b c Orndorff, Wieder & Filkorn 2001, p. 177.
- OSTI 888906.
- ^ Gates & Ritchie 2006, p. 163.
- ^ Turrin et al. 2017, p. 426.
- ^ Wood 1980, p. 146.
- ^ Turrin et al. 2017, p. 428.
- ^ .
- ^ a b Diggles et al. 1986, p. B3.
- ^ Turrin et al. 2017, p. 397.
- ^ a b c d Amin & Valentine 2017, p. 42.
- ^ Valentine, Shufelt & Hintz 2011, p. 758.
- ^ Snyder, R.P.; Ekren, E.B.; Dixon, G.L. (1972). Geologic map of the Lunar Crater Quadrangle, Nye County, Nevada (Map).
- ^ a b c Johnson et al. 2014, p. 27.
- ^ Ruth et al. 2015, p. 399.
- ^ a b Ruth et al. 2015, p. 398.
- ^ a b c d Johnson et al. 2014, p. 28.
- ^ Turrin et al. 2017, p. 421.
- ^ Younger, Valentine & Gregg 2019, p. 2.
- ^ Johnson et al. 2014, p. 29.
- ^ a b Turrin et al. 2017, p. 419.
- ^ Turrin et al. 2017, p. 416.
- ^ a b Hintz & Valentine 2012, p. 22.
- ^ a b Gates & Ritchie 2006, p. 83.
- ^ Hintz & Valentine 2012, p. 26.
- ^ Hintz & Valentine 2012, p. 28.
- ^ a b c Amin & Valentine 2017, p. 41.
- ^ a b Turrin et al. 2017, p. 417.
- ^ Amin & Valentine 2017, p. 48.
- ^ Amin & Valentine 2017, p. 43.
- ^ Gates & Ritchie 2006, p. 70.
- ^ Harp & Valentine 2015, p. 38.
- ^ Harp & Valentine 2015, p. 39.
- ^ Harp & Valentine 2015, p. 41.
- ^ Harp & Valentine 2015, p. 50.
- ^ Harp & Valentine 2015, p. 53.
- ^ a b c d Turrin et al. 2017, p. 392.
- ^ S2CID 45198588.
- ^ a b c d e f Ruth et al. 2015, p. 397.
- ^ Cousens, Wetmore & Henry 2013, p. 32.
- ^ Cousens, Wetmore & Henry 2013, p. 17.
- ^ a b c d e Tadini et al. 2014, p. 4.
- ^ USGS, Extensional tectonic environment.
- ^ Tadini et al. 2014, p. 7.
- ^ a b c Turrin et al. 2017, p. 393.
- ^ Yogodzinski et al. 1996, p. 17425.
- .
- OSTI 838331.
- ^ Gates & Ritchie 2006, p. 38.
- ^ Diggles et al. 1986, p. B6.
- ^ a b c Scott & Trask 1971, p. 12.
- ISBN 978-0-19-965306-5.
- ISBN 978-1-4020-4494-6.
- ^ Hintz & Valentine 2012, p. 20.
- ^ Tadini et al. 2014, p. 13.
- ^ Turrin et al. 2017, p. 400.
- ^ Turrin, Abrahams & Dohrenwend 1987, p. 406.
- ^ Ruth et al. 2015, p. 400.
- ^ Ruth et al. 2015, pp. 397–398.
- ^ a b c Rasoazanamparany et al. 2015, p. 78.
- ^ a b Valentine & Cortés 2013, p. 5.
- ^ Gates & Ritchie 2006, p. 277.
- ^ Ruth et al. 2015, p. 410.
- ^ Ruth et al. 2015, p. 412.
- ^ Ruth et al. 2015, p. 411.
- S2CID 20181547.
- ^ Turrin et al. 2017, pp. 394–395.
- ^ S2CID 54169848.
- ^ Harp & Valentine 2015, p. 37.
- ^ Foland, K. A.; Kargel, J. S.; Lum, C. L.; Bergman, S.C. (1987). "Time-spatial-compositional relationships among alkali basalts in the vicinity of the Lunar Crater, south central Nevada". Geological Society of America Abstracts with Programs. 19: 666.
- .
- ^ Turrin et al. 2017, p. 398.
- ^ Scott & Trask 1971, p. 13.
- ^ USGS, Effusive eruption.
- ^ Scott & Trask 1971, p. 17.
- ^ "Black Rock Lava Flow Nye County, Nevada". Nevada Bureau of Mines and Geology. University of Nevada, Reno. Retrieved 1 August 2019.
- ^ Hintz & Valentine 2012, p. 31.
- ^ Younger, Valentine & Gregg 2019, p. 13.
- Bibcode:2012AGUFM.V53C2852J.
- ISSN 0091-7613.
- ^ Wood 1980, p. 147.
- Bibcode:2013AGUFM.V21B2717H.
Sources
- Amin, Jamal; Valentine, Greg A. (1 June 2017). "Compound maar crater and co-eruptive scoria cone in the Lunar Crater Volcanic Field (Nevada, USA)". Journal of Volcanology and Geothermal Research. 339: 41–51. ISSN 0377-0273.
- Cousens, Brian; Wetmore, Stacey; Henry, Christopher D. (1 December 2013). "The Pliocene–Quaternary Buffalo Valley volcanic field, Nevada: Post-extension, intraplate magmatism in the north-central Great Basin, USA". Journal of Volcanology and Geothermal Research. 268: 17–35. ISSN 0377-0273.
- Diggles, M.F.; Nash, J.T.; Ponce, D.A.; Plouff, Donald; Kness, R.F. (1986). "Mineral resources of the Palisade Mesa and the Wall Wilderness Study Areas, Nye County, Nevada". US Geological Survey Bulletin. doi:10.3133/b1731B.
- Gates, Alexander E.; Ritchie, David (2006). Encyclopedia of Earthquakes and Volcanoes (3 ed.). Infobase Publishing. ISBN 978-0-8160-7270-5.
- Harp, A. G.; Valentine, G. A. (1 March 2015). "Shallow plumbing and eruptive processes of a scoria cone built on steep terrain". Journal of Volcanology and Geothermal Research. 294: 37–55. ISSN 0377-0273.
- Hintz, Amanda R.; Valentine, Greg A. (15 September 2012). "Complex plumbing of monogenetic scoria cones: New insights from the Lunar Crater Volcanic Field (Nevada, USA)". Journal of Volcanology and Geothermal Research. 239–240: 19–32. ISSN 0377-0273.
- Johnson, P. J.; Valentine, G. A.; Cortés, J. A.; Tadini, A. (15 June 2014). "Basaltic tephra from monogenetic Marcath Volcano, central Nevada". Journal of Volcanology and Geothermal Research. 281: 27–33. ISSN 0377-0273.
- Orndorff, Richard L; Wieder, Robert W; Filkorn, Harry F (2001). Geology underfoot in central Nevada. Missoula, Mont.: Mountain Press Pub. Co. OCLC 45023137.
- Rasoazanamparany, C.; Widom, E.; Valentine, G. A.; Smith, E. I.; Cortés, J. A.; Kuentz, D.; Johnsen, R. (18 March 2015). "Origin of chemical and isotopic heterogeneity in a mafic, monogenetic volcanic field: A case study of the Lunar Crater Volcanic Field, Nevada". Chemical Geology. 397: 76–93. ISSN 0009-2541.
- Ruth, Dawn; Sas, Mai; Widom, Elisabeth; Rasoazanamparany, Christine; Johnsen, Racheal; Valentine, Greg A.; Smith, Eugene I.; Cortés, Joaquín A. (1 February 2015). "Intrinsic conditions of magma genesis at the Lunar Crater Volcanic Field (Nevada), and implications for internal plumbing and magma ascent" (PDF). American Mineralogist. 100 (2–3): 396–413. S2CID 130456005.
- Scott, D.H.; Trask, N.J. (1971). "Geology of the Lunar Crater volcanic field, Nye County, Nevada". Geological Survey Professional Paper. Professional Paper. doi:10.3133/pp599I.
- Tadini, A.; Bonali, F. L.; Corazzato, C.; Cortés, J. A.; Tibaldi, A.; Valentine, G. A. (19 October 2014). "Spatial distribution and structural analysis of vents in the Lunar Crater Volcanic Field (Nevada, USA)". Bulletin of Volcanology. 76 (11): 877. S2CID 129032071.
- Turrin, Brent D.; Abrahams, Athol D.; Dohrenwend, John C. (1 September 1987). "Drainage development on basaltic lava flows, Cima volcanic field, southeast California, and Lunar Crater volcanic field, south-central Nevada". GSA Bulletin. 99 (3): 405–413. ISSN 0016-7606.
- Turrin, Brent; Harp, Andrew G.; Briner, Jason P.; Johnsen, Racheal; Rasoazanamparany, Christine; Smith, Eugene I.; Widom, Elisabeth; Cortés, Joaquín A.; Valentine, Greg A. (1 April 2017). "Lunar Crater volcanic field (Reveille and Pancake Ranges, Basin and Range Province, Nevada, USA)". Geosphere. 13 (2): 391–438. .
- USGS. "USGS: Volcano Hazards Program Glossary". Retrieved 8 February 2020.
- Wood, Charles A. (1 October 1980). "Morphometric analysis of cinder cone degradation". Journal of Volcanology and Geothermal Research. 8 (2): 137–160. ISSN 0377-0273.
- Valentine, Greg A.; Cortés, Joaquín A. (30 August 2013). "Time and space variations in magmatic and phreatomagmatic eruptive processes at Easy Chair (Lunar Crater Volcanic Field, Nevada, USA)". Bulletin of Volcanology. 75 (9): 752. S2CID 129717973.
- Valentine, Greg A.; Shufelt, Nicole L.; Hintz, Amanda R. L. (1 August 2011). "Models of maar volcanoes, Lunar Crater (Nevada, USA)". Bulletin of Volcanology. 73 (6): 753–765. S2CID 128745280.
- Yogodzinski, G. M.; Naumann, T. R.; Smith, E. I.; Bradshaw, T. K.; Walker, J. D. (1996). "Evolution of a mafic volcanic field in the central Great Basin, south central Nevada". Journal of Geophysical Research: Solid Earth. 101 (B8): 17425–17445. ISSN 2156-2202.
- Younger, Zachary P.; Valentine, Greg A.; Gregg, Tracy K. P. (13 August 2019). "'A'ā lava emplacement and the significance of rafted pyroclastic material: Marcath volcano (Nevada, USA)". Bulletin of Volcanology. 81 (9): 50. S2CID 199542110.
External links
- Morton, Mary Caperton (2017). Aerial Geology: A High-Altitude Tour of North America's Spectacular Volcanoes, Canyons, Glaciers, Lakes, Craters, and Peaks. Timber Press. ISBN 9781604698350.