Page 49 - Caldera Volcanism Analysis, Modelling and Response

24 Fidel Costa

Table 6 Units, volumes, age data, residence times and process rates of the Long Valley system.
39
3
LongValley Vol (km ) 40 Ar/ Ar, Zircon U--Th dis- Zircon U--Pb
14
Caldera K--Ar or C U--Th equilibrium age (SIMS
age (eruption) disequi- isochron age andTIMS)
librium model
age (SIMS)
Postcaldera

Inyo dome (South 0.13 [M85] ca. 0.6 ka [M85] 30–278 ka [R97],
dead man) 208718 ka
[R97]
Mammoth knolls o1 [H04] 110722 ka–97712 ka 139.175.3 ka–
domes [M86], 11073ka 143.870.9 ka [H02]
[H02]
Deer Mountain o1 [H04] 11573 ka [M86], 120–375 ka [R97], 179.872.0 ka–
dome 10178 ka [H02] 224716 ka 257.773.3 ka
[R97] 235.671.2 ka [H02]
West Moat Coulee 4 [H04] 151 and 14774 ka [H02] 152.672.0 ka–
(or Low Silica 202.670.9 ka
flow) 175.6712.9 ka
[H02]
Caldera
Bishop Tuff (BT) W600 [H79] 762712 ka [I&O94], 81177 ka (early
75973 ka [P92], BT [S&R05]),
76071 ka [vdB&S95] 823711 ka (early
BT [R&C00]),
84178 ka (late BT
[S&R05])
Precaldera
Glass mountain 100720 [H04] 2.1-0.79 Ma [M&M85]
(GM) center
Young Units
GM-Dome YA o3 [M&M91e] 790720 ka [M&M85] 981718 ka [S&R05]

GM-Dome YG o3 [M&M91e] 900730 ka [M&M85] 933717 ka [S&R05]

Old units
GM-Dome OD o2 [M&M91e] 1.3570.10 Ma [M&M85], 1.85370.013 Ma
1.68670.011 Ma [D94] (interiors [S&R05]),
1.70670.035 Ma
(surfaces [S&R05])
GM-Dome OL o1 [M&M91e] 1.670.1 Ma [M&M85],
1.86770.005 Ma [D94]
GM-Dome OC o1 [M&M91e] 1.9270.05 Ma [M&M85],
1.99970.012 Ma [D94]
39
a
Notes: If both 40 Ar/ Ar and K-Ar ages are available only the former are given. Vol, Volumes in dense rock equivalent. This is
b
taken as the difference between the eruption ages and those of other radioactive clocks (e.g., Rb–Sr, U–Th–Pb). These data
refer not only to one dome but use multiple geographically related units. calc., calculation, San, sanidine, Bt, biotite, Qtz,
quartz. Data sources: [A00], Anderson et al. (2000); [B&W02], Bindeman and Valley (2002); [C&D93], Christensen and
DePaolo (1993); [C&H96], Christensen and Halliday (1996); [D94], Davies et al. (1994); [D&H98], Davies and Halliday
(1998); [H79], Hildreth (1979); [H89], Halliday et al. (1989); [H04], Hildreth (2004); [H&D92], Hervig and Dunbar (1992),
[H&D97], Heumann and Davies (1997); [H02], Heumann et al. (2002); [I&O94], Izett and Obradovich (1994); [M&M85],
Metz and Mahood (1985); [M&M91e], Metz and Mahood (1991), the [e] means that no estimate was found in the literature,
and the volumes were calculated from Figure 1of Metz and Mahood (1991) using a thickness of 0.5 km. [M85], Miller (1985);
[M86], Mankinen et al. (1986); [M&B06], Morgan and Blake (2006); [P92], Pringle et al. (1992); [R97], Reid et al. (1997).
Data of [R97] are including all zircons. [R&C00], Reid and Coath (2000); [S&R05], Simon and Reid (2005). Data of [S&R05]
are mean values. [vdB&S95], Van den Bogaard and Schirnick (1995); [W01], Winick et al. (2001), [W07], Wark et al. (2007).